Thalassas An International Journal of Marine Sciences

Number 29 (1) January 2013

TThalassashalassas greek voice meaning...”of the sea” Cover photograph: A 10 liter, 24 bottles Rosette-CTD system is being raised to deck of Spanish R/V Sarmiento de Gamboa, 5 miles off Cape Farewell (Southern Greenland 59º46’N, 43º55’W), on 17 July 2012, during the last station of “Catarina” Cruise (http://catarina.iim.csic.es/en), a transatlantic section departed at Vigo (Spain) on June 22, 2012. Picture courtesy of Rafael García, Captain of R/V Sarmiento de Gamboa.

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I.S.S.N.: 0212-5919 Edition: Servizo de Publicacións Dep. Leg.: C379-83 Universidade de Vigo. Nº 29 (1) - 2013 Campus das Lagoas, Marcosende 36310 Vigo. España. Printed in Vigo. Spain Volume 29(1) THALASSAS AN INTERNATIONAL JOURNAL OF MARINE SCIENCES

EDITORIAL BOARD

Editor-in-Chief

MANUEL J. REIGOSA ROGER Departament of Plant Biology and Soil Science University of Vigo, Spain

Scientific Committee

ALFREDO ARCHE MIRALLES JESÚS IZCO SEVILLANO Instituto de Geología Económica. Faculty of Pharmacy C.S.I.C., Madrid, Spain University of Santiago, Spain

ANTONIO CENDRERO UCEDA JESÚS SOUZA TRONCOSO D.C.I.T.T.Y.M. Facultad de Ciencias. Faculty of Marine Sciences University of Cantabria, Santander, Spain University of Vigo, Spain

CARLOS SOUTO JOHN L. LARGIER Faculty of Marine Sciences Bodega Marine Laboratory University of Vigo, Spain Department of Environmental Science and Policy, University of California, Davis CÁSTOR GUISANDE Faculty of Marine Sciences LUÍS GONZÁLEZ University of Vigo, Spain Departament of Plant Biology and Soil Science University of Vigo, Spain DANIEL REY Faculty of Marine Sciences LUISA ANDRADE University of Vigo, Spain Departament of PlantBiology and SoilScience University of Vigo, Spain FEDERICO ISLA Centro de Geología de Costas MIGUEL Á. NOMBELA University of Mar del Plata, Argentina Faculty of Marine Sciences University of Vigo, Spain FEDERICO VILAS MARTÍN Faculty of Marine Sciences M. RUFUS KITTO University of Vigo, Spain Marine Biology Department, Faculty of Marine Sciences King Abdulaziz University, Jeddah, Saudi Arabia FRANCISCO RAMIL Faculty of Marine Sciences NORBERT P. PSUTY University of Vigo, Spain Center for Coastal and Environmental Studies University of New Jersey, USA GUILLERMO FRANCÉS Faculty of Marine Sciences TAKESHI YASUMOTO University of Vigo, Spain Department of Chemistry, Agricultural Faculty, University of Tohoku, Japan GABRIEL ROSÓN Faculty of Marine Sciences TOMOHIRO KAWAGUCHI University of Vigo, Spain Department of Environmental HealthS ciences The Norman J. ArnoldS chool of Public Health University of South Carolina, USA INSTRUCTIONS FOR THE AUTHORS

Papers should be submitted using the web-based application. If you want to add some materials (software, extended maps, additional material) please contact [email protected] for instructions. The application is accessed from the Journal web page (http://webs.uvigo.es/thalassas). There you should select “Send an article” and follow the instructions. Alternatively, you can directly access the application in the following address: http://recyt.fecyt.es/index.php/Thal

Thalassas publishes papers related to all fields of marine sciences. Bothregular papers, short notes and review papers are accepted. You can also contact previously with the Editor-in-Chief (Manuel Reigosa, [email protected]) this is especially encouraged before submitting review papers or letters.

Articles Thalassas is an international journal that accepts original papers, review papers and short notes about every aspect of marine sciences,especially when a multidisciplinary approach is followed. Language accepted is English. The journal will provide also a summary in Spanish. Authors are allowed to post their accepted papers in their own Web pages. Thalassas will, in any case, provide free to all the scientificcommunity, a version of the published papers to download from the Thalassas Web page. Revision of papers will be done using electronic facilities (that is, referees would receive by e-mail the papers under revision and should answerno later than two weeks after receiving the article by e-mail or fax). Authors can apply for a picture or graphics to be used as a full colour cover image for the paper version. Please state it when you submit your paper.

Full-length papers: Those are original previously unpublished works about any aspect of marine sciences. The title should be indicative of contents, and no longer than 60characters. The first page should include the names of authors and complete affiliations, including e-mail addresses and Web page addressesif any. They will include an abstract (100 - 300 words), followed by less than 15 keywords (both included in the abstract andadditional). Materials and Methods sections will be followed by Results and Discussion. Those sections can be put together if this fits the contentof the Manuscript. Manuscripts should be written in simple sentences, conforming to accepted Scientific Standard English. Texts should be clearconsidering the great scope of the audience (this is not a very specialised journal, covering a broad range of disciplines, although always relatedto marine or coastal ecosystems).

After those sections, Acknowledgements and References should follow. The style of citation will be as follows:

Journal articles: Author AA, Author BB (year). Title of article, Complete name of Journal, number: pages

Book articles: Author AA, Author BB (year). Title of article. In: A Editor, B Editor, eds, Title of Book, Ed, number, Vol number, Publisher, City, pages. Theses Author AA (year) Title of thesis.University, City. The citations should be arranged in the text from earliest to most recent year, alphabetised by name within the same year. In the references list,order by author (s) name, after by year. Finally, figures, tables and captions for figures and tables should be included.

Review papers: Those papers will be published mainly by invitation. But suggestions are also welcome. If you feel that you can contribute with a review, pleasecontact Editor-in-Chief by e-mail.

Technical papers: These papers are especially welcome for the electronic version, but if the editors appreciate their interest, they can also be published in the paperversion. The structure of the article should follow the same recommendations as full-length papers.

Letters: Correspondence prepared for publication in the paper version should not exceed two printed pages. For the electronic version (that will be thepreferred for letters because the speed of publication and the possibility of several responses) no page limit is applied, although the shorter thebest.

Meeting reports and Conference Proceedings: For meeting reports of Conferences about Marine Sciences, the coordinator of the Congress who wishes an abstract to appear in Thalassas (eitherin electronic or paper versions) should contact Editor-in-Chief ([email protected]). Congress Proceedings could also be published as specialnumbers of the journal. Cover Photograph:

A 10 liter, 24 bottles Rosette-CTD system is being raised to deck of Spanish R/V Sarmiento de Gamboa, 5 miles off Cape Farewell (Southern Greenland 59º46’N, 43º55’W), on 17 July 2012, during the last station of “Catarina” Cruise (http://catarina.iim.csic.es/en), a transatlantic section departed at Vigo (Spain) on June 22, 2012. Picture courtesy of Rafael García, Captain of R/V Sarmiento de Gamboa.

INDEX

9-16 Aghzar, M. Miñambres, P. Alvarez & P. Presa A cost-benefit assessment of two multi-species algae diets for juveniles of Mytilus galloprovincialis.

17-23 S. Balamurugan, B. Deivasigamani, S. Kumaran, M. Sakthivel, G. Edward & M. Ashiq Ur Rahman Length-weight relationship, age and growth of wild catfish arius arius (Hamilton, 1822) in Parangipettai East Coast of Tamil Nadu.

25-33 Patricia Esquete, Roger N. Bamber, Juan Moreira & Jesús S. Troncoso Pycnogonids (Arthropoda: Pycnogonida) in seagrass meadows: the case of o grove inlet (NW Iberian Peninsula).

35-58 I. Gadea, M. Rodilla, J. Sospedra, S. Falco & T. Morata Seasonal dynamics of the phytoplankton community in the Gandia coastal area, Southern Gulf of Valencia.

59-75 Deneb Ortigosa, Nuno Simões & Gonçalo Calado Seaslugs (Mollusca: Opisthobranchia) from Campeche bank, Yucatan Peninsula, Mexico.

Thalassas, 29(1) · January 2013 7

Thalassas, 29(1) · January 2013: 9-16 An International Journal of Marine Sciences

A COST-BENEFIT ASSESSMENT OF TWO MULTI-SPECIES ALGAE DIETS FOR JUVENILES OF Mytilus galloprovincialis

A. AGHZAR(1), M. MIÑAMBRES(2), P. ALVAREZ(2) & P. PRESA(2)* (1) Université Abdelmalek Essaâdi, Faculté des Sciences, Laboratoire de Biologie Appliquée et Pathologie, BP. 2121, Mhannech 2, 93002 Tétouan, Morocco (2) University of Vigo, Department of Biochemistry, Genetics and Immunology, ECIMAT-Faculty of Marine Sciences, Illa de Toralla, 36331 Vigo, Spain *Corresponding author: Pablo Presa University of Vigo. Dep. Biochemistry, Genetics and Immunology, 36310 Vigo, Spain Tel. & Fax: +34-986-812567. E-mail: [email protected]

ABSTRACT

The optimisation of productivity in mussel hatchery requires the assessment of multi-species algae diets to enhance growth and survival during retention time. The present study monitored shell length in Mytilus galloprovincialis juveniles using diets of four micro- algae, Tetraselmis suecica, Isochrysis galbana, Phaeodactylum tricornutum and Chaetoceros gracilis. The experiment lasted 116 days to assess shell length response, used a full-sib mussel progeny to minimise familiar effects on growth variance, and enforced a mini-raft suspension system to assure equal food deliverance to all juveniles under treatment. Shell-length increment in the 26% C. gracilis-based diet was not different from the 26% P. tricornutum-based diet except in two samplings. None differences between diets were observed neither in the growth trend nor in survival (99%). Present data indicate that multi-species algae diets incorporating C. gracilis have a slight non-significant positive effect on growth of M. galloprovincialis juveniles and that such growth gain is not compensated by its higher production cost (4 times) as compared to diets composed by cheaper and easy-culturing species such as P. tricornutum. The global cost required to fill a whole raft (ca 200 ropes) using two-month old hatchery-produced mussel juveniles (One month retention time after fixation i.e. juveniles 2,000 μm in length) fed P. tricornutum was less (1,892 €/raft) than that fed C. gracilis (7,551 €/raft) or its equivalent from rocky scrapping (2,000 €/raft).

Key words: Chaetoceros gracilis, cost-benefi t assessment, multi-species algae diets, Mytilus galloprovincialis, Phaeodactylum tricornutum.

RESUMEN (Evaluación de costes y rendimiento de dos dietas microalgales multiespecíficas para juveniles de Mytilus galloprovincialis)

La optimización de la producción de semilla de mejillón en criadero requiere la evaluación de dietas multiespecificas para mejorar el crecimiento y la supervivencia durante la fase de retención. En este trabajo se efectúa el seguimiento de la longitud valvar de juveniles de Mytilus galloprovincialis alimentados con dietas compuestas de cuatro cepas microalgales, i.e. Tetraselmis suecica, Isochrysis galbana, Phaeodactylum tricornutum y Chaetoceros gracilis. El experimento duró 116 días para valorar la respuesta de crecimiento, se empleó una progenie de hermanos completos para minimizar la varianza de crecimiento debida a efectos familiares, y se utilizó un sistema experimental de minibateas en suspensión que aseguró la distribución homogénea de alimento entre los juveniles tratados. El incremento en longitud valvar del grupo sometido a la dieta que contenía 26% de C. gracilis sólo difirió del de la dieta con 26% de P. tricornutum en dos muestreos. No se observaron diferencias entre dietas, ni en la curva de crecimiento ni en la supervivencia juvenil (99%). Estos resultados indican que las dietas multialgales que incorporan C. gracilis provocan un efecto positivo en el crecimiento de juveniles de mejillón pero no es significativo al com- pararlo con dietas similares. Además este efecto positivo de C. gracilis sobre el crecimiento no está compensado por un mayor rendimiento del stock cultivado, pues su coste de producción es 4 veces mayor que el de dietas multialgales más baratas y fáciles de cultivar, tal como las basadas en la especie P. tricornutum. El coste estimado para inocular una batea de cultivo con 200 cuerdas, con juveniles de 2 meses de vida (2.000 μm de longitud), producidos y alimentados en criadero con P. tricornutum (1 mes de retención tras la fijación) es de 1.892 €/batea, i.e. cuatro veces menos que los alimentados con C. gracilis (7.551 €/batea), y menor que su equivalente procedente de la compra de semilla en el mercado (2.000 €/batea).

Palabras clave: Chaetoceros gracilis, costes de producción, dietas microalgales multiespecífi cas, Mytilus galloprovincialis, Phaeodactylum tricornutum.

Thalassas, 29(1) · January 2013 9 A. AGHZAR, M. MIÑAMBRES, P. ALVAREZ & P. PRESA

INTRODUCTION 1975). A higher growth has been observed in bivalves and copepods fed Chaetoceros sp. than fed Phaeodactylum, Live microalgae are believed to provide the most the latter microalgae having a reduced nutritional value important nutrients for bivalves in the wild because of 12% of lipids against 19% of the former (Helm et their shortage trends to prolong the planktonic larval al., 2004; Liu et al., 2009; Puello-Cruz et al., 2009). phase, increasing cohort mortality due to predation However, Chaetoceros sp. is more difficult and expensive (Rumrill, 1990), and to negatively affect spat recruitment to maintain in large volumes than Phaeodactylum. C. in artificial rope collectors. This phenomenon has been gracilis is one of the easier Chaetoceros species for culture observed in several bivalves. For example, Mytilus and is widely used in larger volumes around the world californianus larvae have shown limited growth and (Lambade & Mohamed, 2002). delayed development under unsuitable food supply (Paulay et al., 1985; Pechenik et al., 1990). Mytilus edulis The present study aimed at assessing shell-length veligers have shown limited growth due to food supply growth in M. galloprovincialis juveniles in nursery using scarcity in the embayment during summer (Fotel et al., multispecific diets of the above cited microalgae species, 1999). With the advancement on bivalve reproduction in order to address if the expected higher juvenile growth techniques and juveniles pre-fattening in nurseries, the fed C. gracilis (Medium difficulty cultivation and high culture of live microalgae has become a key requisite energetic efficiency, rich in the PUFA 20:5ω3) compensates for massive production of juveniles (Page & Hubbard, its higher production costs against the cheaper species 1987). Microalgae are used to feed larvae, post-larvae P. tricornutum (Low cultivation difficulty and medium- and juveniles as well as in broodstock conditioning, low energetic efficiency but rich in 22:6ω3). To properly and their production represents 30% - 40% of hatchery estimate the cost-benefit ratio between diets, several operation costs (Coutteau & Sorgeloos, 1992; Helm et growing parameters were fixed, such as the use of a full-sib al., 2004). Therefore, optimisation of microalgae diets progeny of M. galloprovincialis to minimise familiar effects is a commonly sought parameter in bivalve hatchery of mixed progenies on growth variance, the implementation production for larvae and juveniles (Liu et al., 2009). of an in vitro mini-raft suspension system that minimises Bivalve larvae and juveniles are often fed multispecies differences in food availability by all juveniles under algal diets because they exhibit better balancing of the treatment, or an experimental time of 116 days to properly essential nutritional compounds with particular reference assess shell length response under different diets. to polyunsaturated fatty acids, and assure higher growth and survival than single species diets (Enright et al., 1986; MATERIALS AND METHODS Laing & Millican, 1986; De Pauw & Persoone, 1988; Nevejan et al., 2007). On October 15, 2007 a full-sib progeny of M. galloprovincialis was generated in ECIMAT Marine Previous studies have shown growth enhancement of Station (University of Vigo) from wild genitors collected juveniles of some bivalves fed fresh microalgae (Ponis et at Ría de Vigo (NW Spain). A random sample of 11,000 al., 2003; Cragg 2006; Liu et al., 2009) belonging to several 3.5-month-old juveniles from this progeny was reared genera such as Tetraselmis, Isochrysis, Phaeodactylum, under two experimental microalgae diets and a 50-μm Chaetoceros, Pavlova, Dunaliella, Thalassiosira and filtered seawater control, lasting from January 26to May Skeletonema (Helm et al., 2004). The food value of T. 29 in 2008. Five PVC tanks (two for each experimental suecica is considered low possibly because of the presence diet and one for the control) with a dimension of 40 cm of a rigid cell wall which might make it difficult to digest length x 30 cm width x 32 cm depth (Fig. 1a), equipped (Rico-Mora, 1987). However, T. suecica is an appreciated with small growing ropes, were used for the trial. The species because of its high ratio of protein content/cell progeny had been allowed to settle on 13 ropes of 20 volume as compared to that of many other species used cm length at an initial density of approximately 850 in aquaculture. I. galbana has shown some technical individuals per rope (Fig. 1b). The 13 inoculated ropes (six problems in large-scale cultures (Coeroli et al., 1984), per diet (three per tank), and one for control) were placed has no advantage over P. tricornutum, and is a poorer into experimental tanks using horizontal PVC sticks food than C. gracilis. However, I. galbana is an excellent (mini-rafts, Fig. 1b). There were no significant differences food for many filter-feeders (Sukenik & Wahnon, 1991), in initial shell length or weight between the juveniles especially at larval stages (Liu et al., 2009). P. tricornutum randomly distributed among ropes (Table 1). is not generally considered a good food source although it is easy to produce and has been successfully used for Cultured microalgae consisted of Isochrysis galbana growing oyster larvae (Epifanio et al., 1981) and for (Class Prymnesiophyceae; cell of strain # CCMP1323), feeding juveniles of clams and mussels (Foster-Smith, Tetraselmis suecica (Class Prasinophyceae; cell of

10 Thalassas, 29(1) · January 2013 A COST-BENEFIT ASSESSMENT OF TWO MULTI-SPECIES ALGAE DIETS FOR JUVENILES OF Mytilus galloprovincialis

a b

Figure 1: PVC tanks used for mini-raft simulation in the diet trial (Panel a); 20 cm-length culture ropes, each containing 850 juveniles from a full-sib progeny (Panel b) strain # CCMP904), Phaeodactylum tricornutum P. tricornutum (23 μg per 106 cells) (Helm et al., 2004) (Class Bacillariophyceae; Ecimat collection cell of and applied the expression (See Miñambres et al., 2011 strain # CCMP633) and Chaetoceros gracilis (Class for details): Coscinodiscophyceae; cell of strain # CCMP1317). These strains were grown in six litres flasks in a batch system at VD = (C* Vc)/D)*fc where, 20±1ºC and a continuous lighting intensity of 6,000 luxes from three cool daylight fluorescent tubes. Flasks were VD = deliverable volume of C. gracilis bubbled and enriched with Walne’s medium, and pH was Vc=Vt*0.25= deliverable volume of P. tricornutum maintained between 7.4 and 8.3 by unmetered, continuous (25%)

CO2 injection. Collection of cells for feeding was made C= No. cell/ml P. tricornutum as estimated in daily at the exponential growth stage, and cell number per counting microalgae culture was estimated daily using a Neubauer D= No. cell/ml C. gracilis as estimated in daily counting counting chamber and a microscope. fc=23/30=0.77= conversion factor from P. tricornutum to C. gracilis The two experimental multispecies diets conformed as follows: Diet-A was composed by I. galbana and T. Final microalgae formulae was diluted to 60 L with 50 suecica (37% or 60 mg of the equivalent wet weight for μm filtered seawater for better dosing and both diets were each species) and P. tricornutum (26% or 43 mg of the continuously pumped at 0.5-0.6 mL s-1. The tank for the equivalent wet weight); Diet-B was mostly composed control (Diet-C) received a constant supply of 50 μm filtered as Diet-A andbut contained C. gracilis (26% or 43 mg seawater (the same used to prepare Diet-A and Diet-B). All of the equivalent wet weight) instead of P. tricornutum; tanks received a water inflow rate of 40 mL s-1 (complete instead of C. gracilis (26% or 43 mg of the equivalent wet volume replacement every 24 min). Diet-C received an weight); Diet-C orwas the control dietgroup and received average phytoplankton amount from sea water of 2.0 mg a constant supply of 50 μm filtered seawater. The average DW day-1 in the course of the experiment. Experiments number of cells per millilitre at the exponential culturing were conducted at 18±2ºC and tanks were aerated during phase was 12,000,000 for I. galbana, 2,300,000 for T. the experiment to provide oxygen and to prevent microalgae suecica, 15,000,000 for P. tricornutum, and 3,000,000 cell sedimentation. Tanks were cleaned and disinfected for C. gracilisTo achieve a food equivalent of 20% of the three times a week to remove faeces and adherent particles average body wet weight of mussels, the amount of live and juveniles were rinsed with a gently spray of seawater. microalgae delivered to each experimental tank contained The absence of pseudofaeces and the presence of well 163 mg of wet weight day-1 defined faeces at the bottom of the tank indicated an efficient consumption of the whole diet delivered. Growth For daily diet adjustment we usedFig the 1cell organic was calculated in terms of shell length increase (μm day-1). weight established for C. gracilis (30 μg per 106 cells) and Individual shell length was measured every 15 days on a

Thalassas, 29(1) · January 2013 11 A. AGHZAR, M. MIÑAMBRES, P. ALVAREZ & P. PRESA

B A

C

Figure 2: In vitro evolution of shell-length of a 3.5 months-old full-sib progeny during a 116 days retention period. Sampling of juveniles from each multispecies diet was taken at intervals of 1-week (first 53 days) and 2-3 weeks (last 66 days). Diet-A (diamonds), differentially fed 26% Phaeodactylum tricornutum; Diet-B (squares), differentially fed 26% Chaetoceros gracilis; Diet-C (triangles), control diet fed 50-μm filtered seawater. subsample of 50 individuals randomly taken from each 11,500 juveniles per rope and 2,310,000 juveniles per mini-raft feeding. Shell-length measurements were taken 200-rope raft. The cost of juveniles produced in nursery with an image analysis system (Nis elements BR 3.0) for 116 and 30 days of retention was considered for each connected to a magnifying glass (Nikon SMZ 1500). Three multispecies diet. In addition, ten kg of juveniles of 5-15 months after the beginning of the experiment, shell size mm length are required to fill a growth rope. Therefore, a of mussels in the experimental diets was large enough to 200- rope raft requires 2,000 kg such juveniles. The cost replace the optical measurement system by a digital calliper of mussel juveniles from rock-scrapping (1 €/kg) required with 0.01 mm accuracy (Mitutoyo IP67). to fill a raft (2,000€/raft) was also compared to the cost of similar-sized juveniles produced in nursery for 116. Normality length and weight per diet and sample was explored with Kolmogorov-Smirnov test. Shell-length RESULTS measurements taken on serial replicates within diet were compared with a Mann-Whitney test. Comparison of Evolution of shell length within diet average shell length between diets at each sampling as well as between temporal samplings within diet, were Shell length adjusted to a normal distribution in all performed with the Kruskall-Wallis test, the ANOVA serial samplings per diet. No significant weight or length analysis and the ad hoc Scheffée test, all of them differences were observed between replicates within diet implemented in SPSS 17.0. Mortality day-1 was calculated by the end of the trial, i.e. Diet-A (Mann-Whitney test, Z after the number of dead animals (shells) found at the = -2.276, P = 0.023) and Diet-B (Mann-Whitney test, Z = bottom of each experimental tank by the time of shell -1.517, P = 0.129) (Table 1). Average shell length differed length control ca. once a week. significantly within both diets between 2008 samplings on March 10 and 23 (Scheffée test; Diet-A, P = < 0.001, The production costs per rope were calculated from the Diet-B, P < 0.03), as well as between samplings of April experimental data and scaled up for industrial implication. 20 and May 29 (Scheffée test, Diet-A, P < 0.001, Diet-B, P In mussel aquaculture,initial 4.5 mm juveniles taken from = < 0.001) (Fig. 2). Significant pairwise length differences collector ropes or from rocky scrapping are fixed to within Diet-C were observed between samplings March growth ropes suspended from rafts normally placed in 17 and 23 as well as between samplings May 14 and 29 protected areas such as estuaries. After 3 to 5 months (Scheffée test, Control Diet, P < 0.001). growing in the sea juveniles are unfolded into 2-3 ropes of about 50 kg mussels each. After an additional year of Evolution of shell length between diets sea growth we obtain 2-3 harvesting ropes of about 150 kg mussels each (30-35 individuals per kg). Discounting 10% Diet-A and Diet-B grew an average of 47 μm day-1 mortality in the first growing period we finally require and 57 μm day-1 and reached a final length of 8,781±3,545

12 Thalassas, 29(1) · January 2013 A COST-BENEFIT ASSESSMENT OF TWO MULTI-SPECIES ALGAE DIETS FOR JUVENILES OF Mytilus galloprovincialis

Table 1: Shell-length of full-sib M. galloprovincialis juveniles fed two composite microalgae diets (163 mg day-1; Isochrysis galbana, Tetraselmis suecica, Phaeodactylum tricornutum/Chaetoceros gracilis). The experiment lasted 116 days, from January 26th 2008 to May 29th 2008. Different superscripts in the same column indicate significant differences among treatments for α = 0.001.

Treatment Organic weight Diet No. ropes Initial Shell length X ±SD Final Shell length X ±SD Shell-length rate (mg day-1 (%)) (μm) (μm) (μm day-1)

3224.90a 8501.16a A (1) 3 I. galbana 63 (39) ± 940.40 ± 3612.43 3152.19a 8780.69a 47.30± T. suecica 57 (35) ± 937.66 ± 3544.87 15.87 P. tricornutum 43 (26) 3057.46a 9135.76a A (2) 3 ± 939.99 ± 3306.98

3210.30a 10643.97a B (1) 3 ± 891.92 ± 4088.20 I. galbana 63 (39) 3407.67a ± 10234.86a 57.37± T. suecica 57 (35) 986.71 ± 3945.53 20.59 C. gracilis 43 (26) 3371.00a 9724.54a B (2) 3 ± 1045.7 ± 3717.88

50 μm filtered 3257.15a 4867.44b 13.53± 2.0 (100) C 1 - - seawater ± 962.60 ± 1535.37 4.09

μm and 10,235±3,946 μm , respectively. Diet-C grew hatchery-grew juveniles from the present experiment an average of 14 μm day-1 and reached a final length were 37.84 €/rope and 7,568.3 €/raft for P. tricornutum, increment of 4,867±1,536 (Table 1). Growth of mussels respectively, and 151.02 €/rope and 30,203.6 €/raft for C. in the control diet lagged from the start and differed gracilis, respectively. significantly from the two multispecies diets in all samplings (ANOVA, F = 38.884, P = 0; Fig. 2). By the DISCUSSION end of the experiment mussel groups under Diet-A and Diet-B were significantly larger than those under Diet-C Performance of multispecies diets (Mann-Whitney test; Diet-A, Z = -6.444, P = 0; Diet-B, Z = -3.910, P = 0) (Table 1). Significant length differences The coincidence observed across diets regarding between the two multialgal diets were observed only the two samplingss of higher growth (i.e., between in two samplings, March 3 (ANOVA test, F = 49.44, P March 17 and 23 and between May 14 and 29 is < 0.001) andMay 29 (F = 38.88, P < 0.001) this later in likely influenced by a natural enrichment of the nutrient the end of the experiment (Fig. 2). Mortality day-1 of the fraction in the seawater (phytoplankton blooming) intake whole batch of juveniles was significantly less (P < 0.001) to the nursery. Although Diet-A and Diet-B showed a in multispecies enriched sea water (average for the two rough similar shell length pattern across samplings, diets ± SD: 0.075 ± 0.004) than in filtered sea water (0.154 the final larger size of juveniles under Diet-B is in ± 0.015). Survival did not differ between supplemented agreement with previous results obtained on juveniles diets and averaged 99.11 % across the 12 experimental of M. galloprovincialis (Cordero & Voltolina, 1994) mini-ropes. and on post-larvae of Clinocardium nuttallii (Liu et al., 2009) using single species diets, and also with Production costs results on M. galloprovincialis (Whyte et al., 2002) and other cultured species (Puello-Cruz et al., 2009). Such Letting alone common production costs for both studies indicate that Tetraselmis and Isochrysis have the diets, such as the inoculum price (30 € each), the highest protein content, Tetraselmis has the lowest lipids production of algal species common to both diets (T. content, Isochrysis and Chaetoceros have the lowest and suecica, I. galbana) or labour, the volume of C. gracilis the highest ash content, respectively. Such congruence required to obtain an equivalent organic weight to that among studies, diets and species indicates that despite of P. tricornutum implied a 3.99x increment of variable its high ash content, Chaetoceros sp. is one of the most costs (Table 2). The production cost invested to fill a performant living supplementary microalgae nowadays growth rope and a whole raft (200 ropes) with 116 old used in mollusc aquaculture.

Thalassas, 29(1) · January 2013 13 A. AGHZAR, M. MIÑAMBRES, P. ALVAREZ & P. PRESA

Table 2: Estimated differential production costs of juveniles fed two experimental diets; common costs to both species are excluded, e.g. inoculum price, instrumentation or labour costs. The higher volume of C. gracilis required to attain an equivalent organic weight to P. tricornutum, finally rises variable production costs of the former by ≈4 times.

P. tricornutum C. gracilis

Experimental ropea 1 growth ropeb 1 raftc Experimental rope a 1 growth ropeb 1 raftc

No. juveniles 3,400 11,550 2,310,000 3,400 11,550 2,310,000

Volume of algae (L) 102 346.5 69,300 403 1,369 273,803

Volume of Walne medium (mL) 102 600 120,000 403 2371 474,200

Cost of the Walne medium (€) 1.22 7.2 1,440 4.84 28.45 5,690

Electrical consumptiond (€) 9.02 30.6 6,128 36.08 122.57 24,513

Production cost (€) (116 days retention) 10.24 37.84 7,568 40.91 151.02 30,203

Production cost (€) 30 days retention 2.56 9.46 1,892 10.23 37.76 7,551

a Experimental diets were applied during 116 days of retention. b One growth rope requires 10-12 kg of 5-15 mm juveniles. c One typical raft contains about 200 growth ropes. d Electrical consumption required to produce 43 mg day-1 of P. tricornutum or C. gracilis during 116 days, other costs being equal across species. Three fluorescent 36W tubes were used for each of the three cultivation balloons.

Growth of mussel juveniles fed mixed fresh in juveniles-production efficiency. Regarding this, microalgae diets was significantly enhanced regarding the microalgae assayed were collected at 5 days-old monospecific diets (Davis & Cambell 1998; Fotel et al., exponential stage cultures. At this time culture of C. 1999; Puello-Cruz et al., 2009). For comparison of the gracilis averaged 3,000 cells/μl while P. tricornutum shell-length obtained herein with mixed Diet-A (47 μm produced 15,000 cells/μl. Considering that 106 cells of day-1 size increment and final size 8,781±3,545 μm) and C. gracilis weight 30 μg and the same amount of P. Diet-B (57 μm day-1 increment and final size 10,235±3,946 tricornutum cells weights 23 μg (Helm et al., 2004), μm ), the reported length increase of M. edulis juveniles production costs of the same amount of cells (43 mg day- under distinct experimental diets was 4.3 ± 0.4 μm day-1 in 1) per species were ~4 times higher for C. gracilis than filtered sea water, 9.1 ± 0.2 μm day-1 in natural sea water, for P. tricornutum in the same culturing conditions (i.e., 13.1 ± 2.8 μm day-1 in enriched sea water (5x104 cells mL-1 inoculum prize, Walne’s medium, etc.) (Table 1). Such Isochrysis galbana), and 5.6 ± 0.3 μm day-1 to 7.6 ± 1.3 μm higher production costs for C. gracilis (40.91 €) were due day-1 in the wild (Fotel et al., 1999). Although the amount to the higher electrical consumption required to produce of energy in filtered seawater is assumed to reach the equal amounts of cells as for P. tricornutum (10.24 €). minimum required for maintaining the basal metabolic This cost would be reduced by 4 if retention time is rate of mussels (Wong & Levinton, 2004), the two mixed reduced to one month (2.56 € and 10.23 €, respectively) diets assayed resulted in a weight increase that equalled and if large scale production of microalgae and culture fourfold the weight of the control Diet-C (14 μm day-1 and medium are enforced. In this sense, a final approximate final 49% length increase). The high survival (around cost of 1 month retention time would be 1,892 €/raft for P. 99%) of juveniles fed multispecies enriched seawater was tricornutum and 7,551 €/raft for C. gracilis. Taking into close to that observed in M. edulis larvae under different consideration that the number of wild juveniles required food ratios (Fotel et al., 1999). Therefore, in addition to to fill a raft cost about 2,000 € in the market (Table 2), the positive growth enhancement of mussel larvae, fresh it would result profitable the production of juveniles multispecific formulated diets seem to assure a good in hatchery using cheap-optimized multialgal diets. survival of juveniles during retention times prior to raft Several species of Chaetoceros are nowadays included in culture in suspension devices. multialgal diets for molluscs due to their positive synergic role on growth (Puello-Cruz et al., 2009). Nevertheless, Production costs present data indicate that using C. gracilis in multispecies diets does not compensate its high production costs when An optimal balance between production costs and compared to other cheaper and easy-culturing species growth increase during retention times is a key parameter such as P. tricornutum. Provided that acceptable growth

14 Thalassas, 29(1) · January 2013 A COST-BENEFIT ASSESSMENT OF TWO MULTI-SPECIES ALGAE DIETS FOR JUVENILES OF Mytilus galloprovincialis

and survival seem to be guaranteed during hatchery Foster-Smith RL (1975). Some mechanisms for the control retention times, advances in juveniles culturing using of pumping activity in bivalves, Marine Behavior and performant live microalgae would come from reducing it Physiology, 4: 41-60. cost-benefit production ratio. Fotel FL, Jensen NJ, Wittrup L, Hansen BW (1999). In situ laboratory growth by a population of blue mussel larvae ACKNOWLEDGEMENTS (Mytilus edulis L) from a Danish embayment, Knebel Vig, Journal of Experimental Marine Biology and Ecology, 233: This research was funded by Xunta de Galicia through 213-230. grant program Ayudas para la Consolidación de Unidades Helm MM, Bourne N, Lovatelli A (2004). Hatchery culture Competitivas de Investigación INCITE07PXI310152ES. of bivalves: A Practical Manual, FAO Fisheries Technical A. Aghzar has been supported by AECID (Ministerio Paper 471, Rome. Español de Asuntos Exteriores y Cooperación) through Laing I, Millican PF (1986). Relative growth and efficiency of a research scholarship II-A from MAEC-AECID Ostrea edulis L. spat fed various algal diets, Aquaculture, #0000215094 (2007-2008). 54: 245-262. Lambade SB, Mohamed KS (2002). Laboratory - scale high REFERENCES density culture of the marine diatom Chaetoceros sp, Indian Journal of Fisheries, 49(1): 13-21. Brown MR, Jeffrey SW, Garland CD (1989). Nutritional aspects Liu W, Pearce CM, Alabi AO, Gurney-Smith H (2009). Effects of microalgae used in mariculture; a literature review, of microalgal diets on the growth and survival of larvae and CSIRO Marine Laboratories Report, 205: 1-43. post-larvae of the basket cockle, Clinocardium nuttallii, Coeroli M, De Gaillande D, Landret JP (1984). Recent Aquaculture, 293: 248-254. innovations in cultivation of molluscs in French Polynesia, Miñambres M, Pérez M, Alvarez P, Presa P (2011). Cálculo Aquaculture, 39: 45-67. de parámetros elementales para el cultivo de microalgas Cordero B, Voltolina D (1994). Growth of Mytilus en criadero y su aplicación en el diseño de raciones galloprovincialis fed with four microalgae and two feeding alimentarias. In: Métodos y Técnicas de Investigación regimes, Journal of the World Aquaculture Society, 25(3): Marina, JM Estévez, C Olabarria, S Pérez, E Rolán, G 471-476. Rosón (eds.), Chapter XIV: pp. 159-172. Coutteau P, Sorgeloos P (1992). The use of algal substitutes and Nevejan N, Davis J, Little K, Kiliona A (2007). Use of a the requirement for live algae in the hatchery and nursery formulated diet for mussel spat Mytilus galloprovincialis rearing of bivalve molluscs: an international survey, Journal (Lamarck 1819) in a commercial hatchery, Journal of of Shellfish Research, 11(2): 467-476. Shellfish Research, 26(2): 357-363. Cragg SM (2006). Development, physiology, behaviour and Page H, Hubbard DM (1987). Temporal and spatial patterns of ecology of scallop larvae. In: SE Shumway, GJ Parsons, growth in mussels Mytilus edulis on an offshore platform: (eds.), Scallops: Biology, Ecology and Aquaculture, Elsevier relationships to water temperature and food availability, B.V. Amsterdam, pp. 45-105. Journal of Experimental Marine Biology and Ecology, 111: Davis JP, Cambell CR (1998). The use of a Schizochytrium-based 159-179. HUFA enriched dry feed for culturing juvenile mussels Paulay G, Boring L, Strathmann RR (1985). Food limited (Mytilus galloprovincialis) and the comparative routine growth and development of larvae: experiments with natural costs of producing live algae in a commercial bivalve sea water, Journal of Experimental Marine Biology and hatchery. In: H Grizel, P Kestemont (eds.), Aquaculture Ecology, 93: 1-10. and water: fish culture, shellfish culture and water usage, Pechenik JA, Eyster LS, Widdows J, Bayne BL (1990). The Oostende Belgium European Aquaculture Society Spec. influence of food concentration and temperature on growth Publ. 26: 65-66. and morphological differentiation of blue mussel Mytilus De Pauw N, Persoone G (1988). Micro-algae for aquaculture. edulis L. larvae, Journal of Experimental Marine Biology In: MA Borowitzka, LJ Borowitzka (eds.), Micro-algal and Ecology, 136: 47-64. biotechnology, New York, Cambridge U. Press, p 197-221. Ponis E, Robert R, Parisi G (2003). Nutritional value of fresh Enright CT, Newkirk GF, Craigie JS, Castell JD (1986). and concentrated algal diets for larval and juvenile Pacific Evaluation of phytoplankton as diets for juvenile Ostrea oysters (Crassostrea gigas), Aquaculture, 221: 491-505. edulis L, Journal of Experimental Marine Biology and Puello-Cruz AC, Mezo-Villalobos S, González-Rodríguez Ecology, 96: 1-13. B, Voltolina D (2009). Culture of the calanoid copepod Epifanio CE, Valenti CC, Turk CL (1981). A comparison of Pseudodiaptomus euryhalinus (Johnson 1939) with different Phaeodactylum tricornutum and Thalassiosira pseudonana microalgal diets, Aquaculture, 290: 317-319. as foods for the oyster, Crassostrea virginica, Aquaculture, Rico-Mora R (1987). Efecto interactivo de la temperatura y de 23: 347-353. la concentración de microalgas en la fisiología alimenticia y

Thalassas, 29(1) · January 2013 15 A. AGHZAR, M. MIÑAMBRES, P. ALVAREZ & P. PRESA

la energía potencial para el crecimiento de Modiolus capax Whyte JNC, Sherry K, Ginther N, Peribere G (2002). Effects of (Conrard) (Bivalvia:Mytilidae). Thesis Dissertation, Centro a Schizochytrium-based diet in the growth and nutritional de Investigación Científica y de Educación Superior de condition of the mussel, Mytilus galloprovincialis. In: Ensenada, Departamento de Ecología Marina, Ensenada, Aquaculture Canada 2002 Abstracts. http://www. México. aquacultureassociation.ca/ac02/abstracts/mussel. Rumrill SS (1990). Natural mortality of marine invertebrate htm#Whyte. larvae, Ophelia, 32: 163-198. Wong WH, Levinton JS (2004). Culture of the blue mussel Sukenik A, Wahnon R (1991). Biochemical quality of marine Mytilus edulis (Linnaeus, 1758) fed both phytoplankton unicellular algae with special emphasis on lipid composition and zooplankton: a microcosm experiment, Aquaculture I: Isochrysis galbana, Aquaculture, 97: 61-72. Research, 35: 965-969.

(Received: December 9, 2011; Accepted: April 30, 2012)

16 Thalassas, 29(1) · January 2013 Thalassas, 29(1) · January 2013: 17-23 An International Journal of Marine Sciences

LENGTH-WEIGHT RELATIONSHIP, AGE AND GROWTH OF WILD CATFISH Arius arius (HAMILTON, 1822) IN PARANGIPETTAI EAST COAST OF TAMIL NADU

S. BALAMURUGAN, B. DEIVASIGAMANI*, S. KUMARAN, M. SAKTHIVEL, G. EDWARD & M. ASHIQ UR RAHMAN

CAS in Marine Biology, Faculty of Marine Sciences, Annamalai University, Parangipettai-608502

* Email:[email protected]* (corresponding author), Fax: +914144 243641, Ph: 914144237606

ABSTRACT

The catfishes constitute a momentous in terms of fisheries production in asian countries. The over fishing of marine fishes and lose stocks demands extend the studies towards understanding the identity and distribution of the stocks in space and time. The mathematical relationship between length and weight of fishes is a practical index suitable for understanding their sur- vival, growth, maturity, reproduction and general well being. The length weight relationship, age and growth of Arius arius in parangipettai coast of Tamil Nadu were assessed. The study show the length and weight relationship of length groups shows the significant at p < 0.001 except the length groups 6-9 and 21-24 cm. The values of the exponent b in the length-weight relationships W= aLb ranged from 3.1031 to 5.0423 and R2 = 0.9335 to 0.9818. The powell -Wetherall plots analysis shows that the L value was 215.00 mm and K value of 4.684. r = -0.870. The optimized values for K and L were estimated by the ELEFAN I shows 1.30 year-1 and 430.50 mm. The estimated growth performance index (Ø) for. Arius arius were 10.5 and 11 and t0 value of 1.29335. The total blood cell count shows increasing pattern in increasing in length groups. The lowest Blood Cells counts were examined in the 6-9 cm size and maximum counts were occurred in 30-33 cm size fishes.

Key words: Arius arius, length weight, Age and growth, WBC count, parangipettai, Fisat II 1.2.2

RESUMEN (Relaciones longitud-peso, edad y crecimiento del bagre Arius arius (Hamilton, 1822) en la costa Este de Parangipettai en Tamil Nadu)

El bagre es una especie fundamental en cuanto a pesquerías en los países asiáticos. La sobrepesca de peces marinos y la pérdida de poblaciones exige ampliar los estudios dirigidos a la comprensión de la dinámica de los bancos pesqueros en el tiempo y el espacio. La relación matemática entre la longitud y el peso de los peces es un índice práctico adecuado para la comprensión de la supervivencia, el crecimiento, la madurez, la reproducción y el bienestar general de las poblaciones de peces. Se evaluaron el peso, la talla, la edad y crecimiento de ejemplares de Arius arius capturados en Parangipettai (costa de Tamil Nadu). El estudio demuestra una relación estadísticamente significativa (p< 0,001) entre la longitud y el peso excepto en el grupo de tallas de 6-9 cm y 21-24 cm de longitud. Los valores del exponente b en las relaciones talla-peso W= aLb variaron desde 3,1031 hasta 5,0423 con R2 = 0,9335 - 0,9818. El análisis de Powell-Wetherall encontró valores de L= 215,00 mm y K= 4,684, con r = -0,870. Los valores optimizados para K y L se calcularon mediante ELEFAN I alcanzando valores de 1,30 el primer año y 430,50 mm. Los valores estimados del índice de crecimiento global (Ø) para Arius arius fueron 10,5 y 11 con valor de t0= 1,29335. El recuento de glóbulos rojo total muestra un patrón creciente con el aumento de la talla. Los valores más bajos de conteos de células sanguíneas aparecieron en los peces de la categoría de tallas de 6 a 9 cm, mientras que los más altos fueron en peces de 30 a 33 cm.

Palabras clave: Ariusarius, longitud y peso, edad y crecimiento, conteo de células sanguíneas, FISAT II 1.2.2

Thalassas, 29(1) · January 2013 17 S. BALAMURUGAN, B. DEIVASIGAMANI*, S. KUMARAN, M. SAKTHIVEL, G. EDWARD & M. ASHIQ UR RAHMAN

2.0

1.5

1.0

Kn Value

0.5

0.0

6-9 9-12 12-1515-1818-2121-2424-2727-3030-3333-3737-40 Length group (cm)

Figure 1: Study area

INTRODUCTION and general well being. Among marine catfishes, the engraved catfish (Arius arius, Ariidae) major species The catfishes constitute a significant group in terms from the east coasts of India. (Rao K, Venkata Subba of fisheries production as evident from the total world 1982) Length-weight relationships are useful in fishery fish catch of 96.93 million during 1991, where their management for both applied and basic use (Pitcher TJ, contribution was just 0.63%, of which 0.44% was from Hart PJ 1982; Moutopoulos DK, Stergiou KI 2002) 8] to the freshwater and 0.19% from the marine sector. (BBS (i) estimate weight from length observations; (ii) calculate 1989) However, according to the Statistical Bulletin production and biomass of fish population; and/or (iii) published by the Government of India (1993) (Sparre P, provide information on stock or organism condition at the Venema S C 1992) catfishes constitute 15% of the total corporal level and management for comparative growth fish production in India. Catfishes contribute about 14% studies. of the total fish production in Bangladesh as well (Tandon KK 1964). The over fishing of marine fishes and lose METHODOLOGY stocks demands extend the studies towards understanding the identity and distribution of the stocks in space Study area and sample collection and time. A stock is a division of a species showing distinct morphometric characters, inhabiting a particular The samples were collected in Parangipettai (Lat. geographical area in which, its vital stock parameters of 11º 29’N and Long. 79º 46’E) throughout the period of growth and mortality are homogeneous (Kothare PV, Bal August 2010 to July 2011. A total of 650 adult fishes of DV 1976). The exploitation arise when a stock of single both sexes, were collected and brought in the lab, length species in different geographical site. (Kothare PV, Bal and weight were measured. The species were identified DV 1976; Rao K, Venkata Subba 1982; Paramita BN, based on the FAO sheet, (FAO /SIDP 2000.) according to Sadashiv gopal raje 2009). Morphometic studies need to the morphometric and Meristic characters. be supplemented by studies at the genetic level so as to (Paramita BN, Sadashiv gopal raje 2009) confirm whether Morphometric Studies the populations belong to different races or demes. Fresh specimens were used for the measurement, The mathematical relationship between length and using divider and a measuring board the fish were weight of fishes is a practical index suitable for under- measured. Three major morphometric characters were standing their survival, growth, maturity, reproduction studied following. (Appa Rao T 1966; Dwivedi SN,

18 Thalassas, 29(1) · January 2013 LENGTH-WEIGHT RELATIONSHIP, AGE AND GROWTH OF WILD CATFISH Arius arius (HAMILTON, 1822) IN PARANGIPETTAI EAST COAST OF TAMIL NADU

3.0 0

2.5

5 2.0

0 1.5

1.0 5 Condition factor

0.5 0 0.0 6-9 9-12 12-1515-1818-2121-2424-2727-3030-3333-3737-40 6-9 9-12 12-1515-1818-2121-2424-2727-3030-3333-3737-40 Length group (cm) Length group

Figure 2: Figure 3: Kn Value for Arius airus both sex in different length groups. Condition factor K for Arius airus both sex in different length groups.

Menezes MR 1974). The significance of the difference lobe and then weighed to the nearest gram. The allometric between the characters, regressions of each morphometric relationship between length (L) and weight (W) was character on fork length was considered at 5% and 1% calculated by the formula: W = a L b where, W = weight probability level: of an individual fish in gram; L = Length of an individual fish in millimeter ; a and b are constants. The data of 1. Total length (TL): Distance from the tip of the snout to total length and weight were analyzed by the least square the tip of longest caudal ray of the upper lobe when the method (Le Cren ED 1951) using the equation given as: upper lobe is laid back parallel to the scale. Log W = Log a + b Log L where a and b are constants 2. Standard length (SL): Distance from the tip of the estimated by linear regression of the log transformed snout to the end of the vertebral column (structural variates. Length weight relationship was determined base of caudal rays). separately, for both sexes of Arius arius from their 3. Fork length (FL): Distance from the tip of the snout to respective locations and pooled. the end of the middle ray of the caudal fork. To compare length and weight for a particular sample Length-Weight Relationship or individual, condition factors are used (Safran P 1992). One is the Fulton’s condition factor (K), equal to W/L3 For length-weight relationship, the total length was (Fulton TW 1911) while other one is relative condition measured to the nearest millimeter from the tip of the factor (Kn), Kn = W/aLb. In our study we used more snout to the tip of the longest caudal fin ray of the lower homogenous formula of condition factor K=1000W/L3, to know the growth condition of fish (Bauchot R, Bauchot ML 1978). For length frequency data were the fishes were grouped 3cm class intervals. Powell-wetherall method (Beverton RJH, Holt SJ 1966) was used to calculate the ratio of total mortality and growth coefficient (Z/K) as initial estimate of asymptotic length (L). Length frequency data were then analysed by Electronic L Ength Frequency Analysis (ELEFAN I) (Pauly D 1980; Pauly D 1983) using the appropriate routines in FiSAT II package [19]. In this method the growth parameters, asymptotic length (L) and growth coefficient (K) were estimated following the von Bertalanffy growth equation (VBGE)9:

Lt = L (1-exp –-K (t t0)) (1)

where Lt is the length at age t, L the asymptotic length, K the growth coefficient and ‘t0’ age at which fish would

Figure 4: have had zero length if they had always grown according to Powell-Wetherall plots of Arius airus both sex.

Thalassas, 29(1) · January 2013 19 S. BALAMURUGAN, B. DEIVASIGAMANI*, S. KUMARAN, M. SAKTHIVEL, G. EDWARD & M. ASHIQ UR RAHMAN

Figure 5: Growth curves of Arius airus both sex. the above equation. Parameters of L and K were computed RESULT from the ELEFAN I. The growth performance index (Ø) for Arius arius were computed using the following The Morphometric characters of Arius arius were equation10: given in Table 1. The length varies between 6.67-36.8 cm in fork length, 6.27-36 cm in total length and 7.45- 39 cm Ø = log10K + 2 log10 L (2) in standard length, the regression analysis of FL verses TL and SL shows significant different at p< 0.001 the The t0 value from the length-frequency data cannot be ‘a’ value of 0.108 and ‘b’ value of 0 .8832 for FT and estimated by ELEFAN, t0 are estimated by substituting TL and for FL and SL the value are ‘a’’0.0282 and b is the L and K in the following equation11: 0.9136. The length groups, the minimum, maximum and mean length (± S.E.), the minimum and maximum log( t0) -0.176+0.260 logL 1.0 logK (3) weight meansured, the parameters a and b, t-Test, and the coefficient of determination, R2 are presented in Table 2. Total White Cells Count (Wcs) Information on the growth (isometric or allometric) of each group is provided, in Table 2 and growth conditions The blood was drawn up to the mark in WBC pipette K and Kn were presented in figure 1. The estimated and diluted up to the mark11 with diluting fluid for 3 coefficients of the length-weight relationship and other minutes. The cells were then allowed to settle. The cells details of statistical analysis and the results of the in the four corner blocks were counted by using the low ANCOVA analysis are given in Table 2. t-Test also reviles power objective and a medium ocular. The cell counts the isometric growth. The relative condition factor (Kn) were carried out using a Neubauer heamocytomater were calculated (figure 1). And the K values were plotted (Hawksley and Son, England) and were expressed as cells in figure 2 our study shows that the length ranges from ml-1 (Day F 1878). Mean and standard deviation (X±SD) minimum of 7.45±0.85 cm to 38.09±0.65 cm, weight of was calculated for each set of the sample data. 11.41±1.4g to 920.5±33.75g. te length group 6-9 and 21-23

6 /ml -3

5

4

3

2

1 Total White Blood cellscount X 10 0 6 --9 9--12 12--1515--1818--2121--2424--2727--3030--3333--3737--40 Lenght of Fish

Figure 6: Figure 7: Growth performance index (Ø) for Arius arius both sex. Total blood cell count for forArius arius both sex all groups.

20 Thalassas, 29(1) · January 2013 LENGTH-WEIGHT RELATIONSHIP, AGE AND GROWTH OF WILD CATFISH Arius arius (HAMILTON, 1822) IN PARANGIPETTAI EAST COAST OF TAMIL NADU

cm, the morphometric measurements in the present study y=0.336x0.966 shows similarity with those of earlier workers. (Dwivedi 4,5 SN, Menezes MR 1974; FAO /SIDP. 2000) The group 4 3,5 shows difference in length -weight relationship as well as

) 3 Į body depth was observed, probably due to the variations in

t/l 2,5 Ͳ 2 the degree of fullness of stomach, as comparable with the LN(1 Ͳ 1,5 1 inference (Jaiswar AK, Devaraj M 1989) in Megalaspis 0,5 cordyla. The correlation analysis shows ‘b’ value of b<3 0 1 2345678910 11 other than 6-9, 21-23,27-30 and 30-33 groups. Depending Age upon the deviation of ‘b’ values fishes can be classified into three group according (Anibeze CIP 1995) (i) b=3 where the body form of fish remains constant at different Figure 8: Age and length chat t0 of Arius arius both sex. lengths (isometric) (Allen KR 1938). (ii) b<3 when fish becomes more slender as the length increases and (iii) were not significantly different in ANOVA analysis. b>3 (allometric) when fish grows stouter with increase of Other groups shows significantly different at P< 0.05with length. (Growner HJ, Rogelio OJ 1976). b value ranges from 3.262 to 5.5475 This may due to change in factors which effect the The Powell-Wetherall plots was plotted using Fistat growth of the fish; those may be including season, habitat, II (Beverton R J H et al., 1956) gave an initial estimate gonadal maturity, sex, stomach fullness, and health of Lmax value of 215.00 mm and Z/K value of 5.231 [r and reservation techniques. (Pica A, Corte FD 1987; = -0.870; regression equation, Y = 215.0 + (-0.870)*X]. Pitchappan RM 1980) Hence the change in weight is due (Figure 3) These initial estimates were fed into ELEFAN to changes in form but not in specific gravity. Cube law is I package producing optimum growth. The best optimum not confirmed for all fishes because growth causes for the value VBGF growth constant (K) was estimated 1.30 change of their shape. (Pitcher. Pitcher TJ, Hart PJ 1982) year-1 by ELEFAN I shown in Figure 4. The estimated also described that a value less than 3.0 indicated that fish growth performance index (Ø) for. Arius arius were becomes lighter (negative allometric) and greater than 10.5 and 11 (Figure 5). The response surface (Rn) was 3.0 as heavier (positive allometric) for a particular length calculated as 0.253 which is the best combination of as it increase in size. (Rao K, Venkata Subba 1982). The growth parameters are L ∞ =598.09 and K=1.30 Yr-1 for regression analysis on the log transformed data showed a 2 Arius arius, estimated t0 value was 1.2933 figure 6 stronger relationship of both the sexes. R and t-Test also reviles the isometric growth. This means they tend to Comment sex: Lt = 215.00(1-exp–1.30 (t + 1.29335)) become thinner as they grow larger.

Total White Blood Cell Count Kn values were above 1.0 in all group showing that the fish were in better condition in this geographical The minimum Total White blood Cells count was region. It may due to food availability and gonadal observed in 6-9cm group fishes and maximum counts development. They were similar reported by number of were occurred in 30-33 cm in March 2011. Figure 7. authors in different fish species (Romano N et al., 2002) in Trematomus bernacchii, (Sailendri K, Muthukkaruppan DISCUSSION VR 1975b) Tilapia mossambica, (Shafi M, Quddus MMA 1974b) .in Cirrhinus mrigala, (Pica A, Corte FD 1987) The length - weight relationship of Arius arius shows snake eel Pisodonophis boro, (Shafi M, Quddus MMA isometric growth other than 6-9, 21-24, 27-30 and 31-33 1974b) Hilsa ilisha. (Smith M, Potter M, Merchant B

Table 1: Morphometric Character of Arius arius.

Morphometric characters

Measurements (cm) Min (cm) Max (cm)

Total length (TL) 6.5 39

Fork length (FL) 5.9 36.8

Standard length (SL) 5.4 33.90



Thalassas, 29(1) · January 2013 21 S. BALAMURUGAN, B. DEIVASIGAMANI*, S. KUMARAN, M. SAKTHIVEL, G. EDWARD & M. ASHIQ UR RAHMAN

Table 2: The K values obtained for unsexed in the present study Explanatory statistics and estimated parameters of length-weight relationship of Arius airus of parangipettai coast south India. are also quite high from the recorded values 3 4.68 The t0 recorded previously for this species was 1.298 whereas the t0 values were compared to the G. setifer Length Mean Mean group Length ± weight± A b R2 t0 value of males and females shows -0.0817 reported by Growth (cm) SD (cm) SD (g) T-Test Sivashanthini K, Ajmal Khan S 2004. 0.4787 b<3 7.45±0.85 11.41±1.4 1.4267 6-9 ns 0.0163 CONCLUSION 10.55±1.01 0.0627 3.262 s b<3 9-12 28.9±2.05 0.9818 3.5733 b>3 this study updates the length weight relationship, age 13.7±0.79 53.14±2.09 0.4291 12-15 s 0.987 and growth of Marine Catfsh Arius arius in parangipettai 5.5475 b>3 waters during the one year survey. The fish were healthy 15.44±0.82 15-18 98.85±14.8 5.0423 s 0.9459 in all length groups.and it shows the the average of 10-11

120.11±29. b<3 year of age for a fish in this region. 19.3±0.92 3.057s 18-21 6 1.4569 0.1797

1.1653 b<3 22.57±1.09 171.9±6.97 0.5086 21-24 s 0.9456 LIST OF ABBREVIATIONS

198.5±8.76 3.9729 s b>3 24-27 25.5±1.04 4.401 0.1335 TL- Total length 218.8±15.4 b<3 0.2258 1.7123 FL- Fork Length 27-30 28.7±0.99 6 s 0.9713 SL-Standard Length 346.5±19.0 2.5864 b<3 31.76±0.82 1.4881 30-33 7 s 0.9765 K- condition factor Kn- Relative Condition factor 3.2031 b<3 2 34.44±1.01 525.0±35.0 s R - Coefficient of Determination 33-37 0.8956 0.9019 8 W = the weight of the fish in grams, 920.5±33.7 3.2095 b<3 37-40 38.09±0.65 3.1031 0.0636 L = the total length of the fish in centimeters 5 s a = exponent describing of the rate of change ssignificant at P <0.001 of weight with length 1970) in Lepomis macrochirus, (Sivashanthini K, Ajmal b = weight at unit length Khan S 2004) in Gerres setifer the present study showed Arius arius shows the 215.00 mm total length at the end of ACKNOWLEDGEMENT the first year. These values are much lower as compared to the earlier the length (Sivashanthini K, Ajmal Khan S We thank our Dean of Faculty of Marine Science,

2004). In addition, the L∞ (34.4 cm) is slightly larger than Annamalai University for Providing Opportunity to this the maximum observed length, which also suggests that work. This Work was financial Supported by MoES – the growth estimates for spotted catfish by the length OASTC, New Delhi, India. frequency analysis are reliable. In the course of progress in fishery research, different methods have been evolved REFERENCES for determining the age of the fish in an open system. Ford- Walford used to (i) integrated method, (ii) month BBS (1989). Statistical pocketbook of Bangladesh. Bangladesh mode curve and (iii) probability plot method. In this Bureau of Statistics. Statistics Division, Ministry of present study shows L values above the L∞ max. The Planning, Governrnent of Bangladesh, Dhaka; 348. computed L is 215.00 in the present study are higher Sparre P, Venema SC Introduction to tropical fish stock than the recorded value (215.00) for Arius arius unsexed. assessment.. In: Manual. FAO Fisheries Technical Paper,

Table 3: Length and age analysis of Arius arius in Fisat II 1.2.2.

Method Sex L’(mm) Z/K K(yr-1) Rn/Score

Powell - Both 598.09 5.231 - - Wetherall ELEFAN I Both 430.50 - 1.30 0.253 (i)Automatic scan (ii) K- Scan Both 430.50 - 0.410 0.285

22 Thalassas, 29(1) · January 2013 LENGTH-WEIGHT RELATIONSHIP, AGE AND GROWTH OF WILD CATFISH Arius arius (HAMILTON, 1822) IN PARANGIPETTAI EAST COAST OF TAMIL NADU

306,. 1, 2 Rome, 27. Gayanilo FC, Pauly D (1996). The FAO-ICLARM Stock Tandon KK (1964). Biology and fishery of ‘Choo Parai’– Assessment Tools (FiSAT) User’s Guide. FAO Computerized Selaroides leptolepis (Cuvier and Valenciennes) Part III: Information Series: Rome. Population Studies. Indian Journal of Fisheries 9; 1: 10-36. Day F (1878). The fishes of India. ln: Vol. 1.2, Reprinted 1958, Kothare PV, Bal DV (1976). Morphometric study of Sphyraena William Dawson and Sons Ltd, London; 210-215. obtusata (Cuv. and Val.) off Ratnagiri and Janjira. Journal of Jaiswar AK, Devaraj M (1989). Morphometric study of Biological Science, 19; 66-70. Megalaspis cordyla (Linnaeus, 1758) along the northwest Rao K, Venkata Subba (1982). Studies on the populations of coast of India. Journal of Indian Fisheries Association, 19; Saurida tumbil (Bloch) from Indian waters. Indian Journal 1-6. of Fisheries, 29; 8 -19. Anibeze CIP (1995). Aspects of the ecobiology of Heterobranchus Paramita BN, Sadashiv gopal raje (2009). Morphometry and longifilis (Val. 1840) in Idodo river basin (Nigeria) and their length weight relationship of the Catfishes Arius caelatus application to aquaculture. Ph.D. thesis. University of (Valenciennes, 1840) and Arius thalassinus (Ruppell, 1837) Nigeria, Nsukka, off Mumbai, Veraval and Vishakhapatanam coasts. Asian Allen KR (1938). Some observations on the biology of the trout Fisheries Science; 22: 215-228. (Salmo trutta) in Windermere. Journal of Animal Ecology, . Pitcher TJ, Hart PJ (1982). Fisheries Ecology. Chapman and 7; 333-347. Hall: London. Growner HJ, Rogelio OJ (1976). Length-weight relationship Moutopoulos DK, Stergiou KI (2002). Length-weight and of pond raised milk fish in the Philippines. Aquaculture, length-length relationships of fish species from Aegean Sea 7; 339-346. (Greece). Journal of Applied Ichthyology, 18; 200-203,. Pica A, Corte FD (1987). Haemopoiesis, lymphomyeloid tissues, FAO /SIDP. (2000.). Species Identification Sheet-Arius caelatus. spleen and thymus of Torpedoes in normal conditions and Arius thalassinus. Fisheries global information system after treatment with cobamamide and folic acid. Archivio (FIGIS). Food and Agricultural Organization of the United Italiano di Anatomia e di Embriologia, 92; .249–261. Nations, Rome, Pitchappan RM (1980). Review on the phylogeny of splenic Appa Rao T (1966). On some aspects of biology of Lactarius structure and function. Developmental Comparative lactarius (Schn). Indian Journal Fisheries, 13; 334-349. Immunology 4: .395–416. Dwivedi SN, Menezes MR (1974) A note on morphometry and Romano N, Ceccariglia S, Mastrolia L, Mazzini M (2002). ecology of Brachiunius orientalis (Bloch and Schenider) in Cytology of lymphomyeloid head kidney of Antarctic fishes the estuary of Goa. Geobios, 1; 80-83. Trematomus bernacchii (Nototheniidae) and Chionodraco Le Cren ED (1951). The length-weight relationships and seasonal hamatus (Channicthyidae). Tissue and Cell. 34; 2. cycle in gonad weight and condition in the perch (Perca Sailendri K, Muthukkaruppan VR (1975b) Morphology of fluviatilis). Journal of Animal Ecology, 20; 201-219. lymphoid organs in a cichild teleost, Tilapia mossambica Safran P (1992). Theoretical analysis of the weight–length (Peters). Journal of Morphology; 147; 109-122. relationships in the juveniles. Marine Biology, 112; 545-551. Shafi M, Quddus MMA (1974b). The length-weight relationship Fulton TW (1911). The Sovereignty of the Sea. Blackwood: in the carp, Cirrhinus mrigala (Hamilton-Buchanan). Dacca Edinburgh. University Studies, 22; 39-45. Bauchot R, Bauchot ML (1978). Coefficient de condition at Shafi M, Quddus MMA (1974b). The length-weight and length- indice ponderal chez les Teleosteens. Cybium, 3;: 3-16 girth relationship and condition in Hilsa ilisha (Clupeidae). Beverton RJH, Holt SJ (1966). On the dynamics of exploited fish Bangladesh Journal of Zoology, 2; 179-185. populations. Fisheries Investigates: London. Smith M, Potter M, Merchant B (1970). Plasmacytopoiesis in the Pauly D (1980). On the interrelationships between natural pronephros of the teleost, Lepomis macrochirus. Journal of mortality, growth parameters and mean environmental Immunology; 99; .876-882. temperature in 175 fish stocks. ICES Journal of Marine Sivashanthini K, Ajmal Khan S (2004). Population dynamics Science 39: 175-192. of silver biddy Gerres setifer (Pisces: Perciformes) in Pauly D (1983). Some simple methods for the assessment of the Parangipettai waters, southeast coast of India. Indian tropical fish stocks. FAO Fisheries Technology, 23; 1-52. Journal of Marine Sciences, 33; 346-354.

(Received: May 16, 2012; Accepted: August 27, 2012)

Thalassas, 29(1) · January 2013 23

Thalassas, 29(1) · January 2013: 25-33 An International Journal of Marine Sciences

PYCNOGONIDS (ARTHROPODA: PYCNOGONIDA) IN SEAGRASS MEADOWS: THE CASE OF O GROVE INLET (NW IBERIAN PENINSULA)

PATRICIA ESQUETE (1*), ROGER N. BAMBER (2), JUAN MOREIRA (3) & JESÚS S. TRONCOSO (1)

(1) Departamento de Ecología y Biología Animal, Facultad de Ciencias del Mar, Universidad de Vigo, E-36310 Vigo, Pontevedra, Spain. (2) ARTOO Marine Biology Consultants, Ocean Quay Marina, Belvidere Road, Southampton SO14 5QY, UK. (3) Departamento de Biología (Zoología), Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain. *Corresponding author: [email protected]

ABSTRACT

Quantitative studies dealing with the ecology of the Pycnogonida (Arthropoda) are scarce. In this work, the pycnogonid fauna present in the seagrass meadows (Zostera spp.) of an estuarine environment in NW Spain are studied, including spatial distribution and intra-annual seasonal variations of density and diversity. Quantitative sampling showed that the pycnogonid taxocoenosis associated with seagrass meadows was rich and diverse. The best represented species in terms of distribution and abundance were Callipallene tiberi, Achelia echinata and Anoplodactylus pygmaeus. Abundances showed a strongly seasonal pattern, with the highest values in September and lowest in March. Temporal variations in the population dynamics of A. echinata suggest a strong coupling with the life story of the seagrass Zostera marina, which in turn determines the availability of food resources for the pycnogonid assemblage.

Key words: Pycnogonida, diversity, distribution, seagrass, Atlantic Ocean.

RESUMEN (Picnogónidos en praderas de fanerógamas marinas: El caso de la ensenada de O Grove (NO de la Península Ibérica)

Hasta la fecha, son escasos los estudios cuantitativos que han tratado la ecología de la clase Pycnogonida (Arthropoda). En este trabajo, la fauna de picnogónidos presente en las praderas de fanerógamas (Zostera spp.) en un ambiente estuárico del noroeste de España, incluyendo su distribución espacial y las variaciones estacionales de densidad y diversidad. Los datos cuantitativos obtenidos muestran que la taxocenosis de picnogónidos asociada a las fanerógamas es rica y diversa. Las espe- cies mejor representadas en términos de distribución espacial y abundancia fueron Callipallene tiberi, Achelia echinata y Anoplodactylus pygmaeus. Los valores de abundancia mostraron un patrón fuertemente estacional, con los mayores registros en el mes de Septiembre y los más bajos en Marzo. Las variaciones de abundancia en la población de A. echinata sugieren un patente acoplamiento con el ciclo vital de Zostera marina, que a su vez determina la disponibilidad de recursos alimentarios para los picnogónidos.

Palabras clave: Pycnogonida, diversidad, distribución, fanerógamas marinas, Océano Atlántico.

Thalassas, 29(1) · January 2013 25 PATRICIA ESQUETE, ROGER N. BAMBER, JUAN MOREIRA & JESÚS S. TRONCOSO

Figure 1: Location of O Grove inlet and the sampling sites.

26 Thalassas, 29(1) · January 2013 PYCNOGONIDS (ARTHROPODA: PYCNOGONIDA) IN SEAGRASS MEADOWS: THE CASE OF O GROVE INLET (NW IBERIAN PENINSULA)

INTRODUCTION particular, the dynamics and structure of a population of Achelia echinata is investigated from the data obtained The class Pycnogonida is an exclusively marine group and related to the presence and the life history of the of arthropods also known as “sea spiders”, with no clear seagrasses. affinities to any other group and considered either as a sister group to the Euchelicerata or as the sister group MATERIAL AND METHODS to all extant rest of the Euarthropoda (Bamber, 2007; 2010; Arango and Wheeler, 2007). Pycnogonids are The O Grove inlet is an estuarine environment predominantly benthic, slow-moving organisms, and feed situated in the northwest coast of the Iberian Peninsula mainly on sessile prey such as algae, hydroids, actiniarians between 42º41′ –42º28′N and 09º01′ –08º44′W (Figure and bryozoans (Wyer and King, 1974; Bamber and 1). Most of its intertidal and shallow subtidal sediments Davis, 1982); generally, their abundances depend on the are covered by meadows of Zostera marina and Z. noltii. availability of food resources (Roberts, 1981; Arnaud and The area is subjected to seasonal freshwater inputs Bamber, 1987). Other factors such as salinity gradients from several streams and a high level of precipitation in (Wolff, 1976) and hydrodynamics (Munilla León and San autumn/winter. Vicente, 2000) have also been reported to influence their local abundance and distribution. In December 1996, benthic samples were taken with the aim of characterizing the spatial distribution of the Quantitative studies dealing with the ecology of macrofaunal assemblages present in the meadows. Five pycnogonids are scarce (but see Wolff, 1976; Munilla, replicate samples were taken from each of ten sites by 1981; 1991; Arnaud and Bamber, 1987 and references means of a van Veen grab covering a total area of 0.28 therein; Sánchez and Munilla, 1989; Pérez-Ruzafa and m2 for each site (Table 1; Figure 1); additional details on Munilla, 1992; Munilla and Nieto, 1999; Genzano, 2002; location and abiotic features of the sampling sites may Soler i Membrives et al., 2009). In fact, most of the data be found in Esquete et al. (2010). A sample of the bottom available for tropical and temperate areas come from water was taken by means of a Niskin bottle and salinity, wider studies on benthic community ecology where temperature and pH were measured in situ. pycnogonids are rarely found in high numbers; these data usually do not allow a reliable characterization of In addition, temporal samples were taken bimonthly patterns in their environmental needs, ecological role or between May 1998 and March 1999 at a subtidal Z. population dynamics. marina meadow (corresponding to site 3; see Table 1) to study the seasonal dynamics of the fauna. This site Seagrass meadows constitute complex habitats and was selected for the good state of conservation of the are considered as “ecosystem engineers” because they Zostera meadow; furthermore, it was assumed that it favour the settlement and maintenance of high benthic would be less affected by salinity fluctuations than species diversity in temperate and tropical waters meadows situated in more sheltered areas. For this (Montadouin and Sauriau, 2000; Hasegawa et al., 2008) study, samples were taken by SCUBA divers, collecting including that of pycnogonids (Arnaud and Bamber, five replicate quadrats of 25 x 25 cm (0.065 m2) in 1987; Chimenz et al., 1993). In the Iberian Peninsula, each occasion. The shoot and the rhizome fractions some data on pycnogonids occurring in seagrass beds in of the seagrass (the latter including the sediment) the Mediterranean Sea are provided by De Haro (1967), were kept separately in plastic bags and their fauna Munilla (1981) and Arnaud (1988). Pycnogonids may sorted separately. Abiotic parameters were measured play an important role in seagrass meadows because following the same methodology as in the previous of their feeding on sessile epibiont organisms which phase. settle there (Arnaud and Bamber, 1987); therefore, understanding their distribution patterns, habitat For both studies, samples were sieved through a preferences and temporal dynamics will be necessary 0.5 mm mesh and fixed in 10% buffered formalin. to assess the structure and functioning of assemblages Specimens were later sorted, identified, and preserved inhabiting those habitats. in 70% ethanol. Specimens were measured using a stereomicroscope fitted with a micrometer eyepiece. In this work, the composition and diversity of the pycnogonid assemblage present in the seagrass meadows Pycnogonid classification follows that used by Bamber (Zostera marina L. and Z. noltii Hornem.) of an estuarine (2007; 2010). The body length of specimens was measured environment (O Grove inlet, NW Spain) is studied from the anterior margin of the cephalon to the posterior quantitatively on a spatial and temporal scale. In margin of the last lateral processes.

Thalassas, 29(1) · January 2013 27 PATRICIA ESQUETE, ROGER N. BAMBER, JUAN MOREIRA & JESÚS S. TRONCOSO

RESULTS Remarks.- Achelia echinata is a common, abundant and widespread species in the north Atlantic. In the Zostera Spatial study meadows of O Grove, this species was very abundant, particularly in the subtidal meadow corresponding to A total of 232 individuals belonging to 9 species was site 3 (Tables 1, 2). The temporal study at this site found in 9 out of 10 sampling sites in December 1996 provided enough individuals to allow the examination (Table 1). The most abundant species was Callipallene of the population dynamics of this species. There was tiberi (Dohrn, 1881) (85 individuals, 36.6% of total an increase in the number of individuals from spring abundance) followed by Achelia echinata Hodge, 1864 through summer, reaching a maximum in September and (72 indiv., 31.0% of total abundance) and Anoplodactylus declining through autumn and winter until the following pygmaeus (Hodge, 1864) (57 indiv., 24.6% of total spring. The highest proportion and numbers of juveniles abundance). These three species accounted for the 91% were found in July, decreasing to a minimum in March of the total pycnogonid abundance. The most widespread (Figure 2). Gravid females were found throughout the species in the inlet was A. pygmaeus (present in 8 out of year, although in small numbers (1-5 per sample); five 10 sites), followed by C. tiberi (7 sites). ovigerous males were found in March.

Temporal study Family NYMPHONIDAE Wilson, 1878 Genus Nymphon Fabricius, 1794 During the studied period, 297 individuals belonging to 7 Nymphon gracile Leach, 1814 species were found (Table 2). Achelia echinata was by far the numerically dominant species, accounting for 72.1% of total Material examined.- Temporal study (site 3): 2 unsexed abundance (214 individuals), followed by Anoplodactylus specimens, May 1998; 1 unsexed spec., July 1998; 2 pygmaeus (13.1% of total abundance, 39 indiv.). unsexed spec., September 1998; 3 unsexed spec., January 1999; 1 ♂ (ovigerous), 3 unsexed spec., March 1999. The maximal values of number of species and of individuals were obtained in September (88 individuals, Body size.- 1.8-4.5 mm. ♂ with eggs 4.6 mm. 7 species); the lowest abundance was recorded in May (26 indiv.). Achelia echinata was present on all sampling Distribution.- Atlantic and Mediterranean European occasions (6) followed by A. pygmaeus, C. tiberi and N. waters. Iberian Peninsula: Cantabrian coast (Munilla, gracile (5 each). 1987), Ría de Vigo (Anadón, 1975).

SYSTEMATICS Remarks.- In March 1999, one male was found carrying four egg masses. Class PYCNOGONIDA Latreille, 1810 Family AMMOTHEIDAE Dohrn, 1881 Family CALLIPALLENIDAE Hilton, 1942 Genus Achelia Hodge, 1864 Genus Callipallene Flynn, 1929 Achelia echinata Hodge, 1864 Callipallene brevirostris (Johnston, 1837)

Material examined.- Spatial study (December 1996): 6 Material examined.- Spatial study (December 1996): 1 ♂, ♀♀, site 1; 12 ♀♀, 23 ♂♂, 2 juveniles, site 3; 4 ♀♀, 3 ♂♂, 3 1.0 mm, site 5. juveniles, site 4; 3 ♂♂, site 6; 7 ♂♂, site 7; 1 ♀, 1 ♂, site 8; 4 ♀♀, 1 ♂, 1 juvenile, site 9. Temporal study (site 3): 7 ♀♀, Distribution.- North Atlantic, Mediterranean and Black 2 ♂♂, 8 juveniles, May 1998; 5 ♀♀, 4 ♂♂, 13 juveniles, Sea. Iberian Peninsula: Alborán Sea and Gibraltar July 1998; 18 ♀♀, 13 ♂♂, 32 juveniles, September 1998; (Munilla, 1993). 11 ♀♀, 9 ♂♂, 21 juveniles, November 1998; 16 ♀♀, 8 ♂♂, 10 juveniles, January 1999; 15 ♀♀, 9 ♂♂ (5 ovigerous), 1 Callipallene emaciata (Dohrn, 1881) juvenile, March 1999. Material examined.- Spatial study (December 1996): 3 Body size.- ♀♀: 0.5-2 mm; ♂♂: 0.6-1.1 mm; juveniles: ♀♀, site 5; 3 ♀♀, site 9; 1 ♀, 2 juveniles, site 10. Temporal 0.3-0.9 mm. study (site 3): 1 ♂, 1 ♀, 1 juvenile, September 1998; 1 juvenile, November 1998; 5 ♀♀, January 1999. Distribution.- Widely distributed in the Atlantic and Mediterranean Sea, including around the Iberian coasts Body size.- ♀♀ 0.8-1.1 mm; ♂♂ 1.2 mm; juveniles 0.6 (De Haro, 1965; Munilla, 1987). mm.

28 Thalassas, 29(1) · January 2013 PYCNOGONIDS (ARTHROPODA: PYCNOGONIDA) IN SEAGRASS MEADOWS: THE CASE OF O GROVE INLET (NW IBERIAN PENINSULA)

Figure 2: Abundance (individuals/0.312 m2) of juveniles, adult females and adult males of Achelia echinata in site 3 from May 1998 to March 1999.

Distribution.- North-east Atlantic and Mediterranean Distribution.- British Isles, Mediterranean Sea, Canary Sea. Iberian Peninsula: Cantabrian coast (Munilla, 1987), Islands. Iberian Peninsula: SE Iberian Peninsula and Ria de Vigo (Anadón, 1975), Gibraltar (Munilla, 1988), Gibraltar Strait (Munilla, 1991), Mediterranean coast Mediterranean coast (Munilla, 1991). (Munilla León and San Vicente, 2000).

Callipallene spectrum (Dohrn, 1881) Family PHOXICHILIDIIDAE Sars, 1891 Genus Anoplodactylus Wilson, 1878 Material examined.- Spatial study (December 1996): 1 ♀, Anoplodactylus petiolatus (Hodge, 1864) 1 ♂, site 5; 1 ♀, 1 ♂, site 8. Temporal study (site 3): 1 ♀, 2 ♂♂, September 1998; 1 ♂, 3 ♀♀, November 1998. Material examined.- Spatial study (December 1996): 2 ♀♀, 1 mm, site 1. Body size.- ♀♀ 0.9-1.2 mm; ♂♂ 1.0-1.2 mm. Distribution.- Widely distributed from western to Distribution.- South of Great Britain, Atlantic coast of Spain, eastern Atlantic, Mediterranean and Black seas. Iberian Mediterranean Sea (De Haro, 1965; Munilla, 1993). Peninsula: Cantabrian coast (Munilla, 1987), Galician Rías (Moreira and Troncoso, 2007), SE Iberian Peninsula, Callipallene tiberi (Dohrn, 1881) Gibraltar Strait (Munilla, 1993), Mediterranean coast (De Haro, 1967). Material examined.- Spatial study (December 1996): 9 ♀♀, 1 ♂, site 3; 2 ♀, site 4; 35 ♀♀, 4 ♂♂, 1 juvenile, site Anoplodactylus pygmaeus (Hodge, 1864) 5; 1 ♀, site 6; 13 ♀♀, 1 ♂, site 8; 6 ♀♀, 1 ♂, 3 juveniles, site 9; 7 ♀♀, 1 ♂, site 10. Temporal study (site 3): 1 ♀, 1 ♂, Material examined.- Spatial study (December 1996): 3 2 juveniles, May 1998; 1 ♀, July 1998; 2 ♀♀, September ♀♀, 1 ♂, 1 juvenile, site 1; 3 ♀♀, 4 ♂♂, site 3; 6 ♀♀, site 1998; 1 ♀, November 1998; 2 ♀♀, 1 ♂, March 1999. 4; 1 ♀, 4 ♂♂, site 5; 13 ♀♀, 9 ♂♂, site 6; 1 ♀, 1 ♂, site 7; 2 ♀♀, site 8; 5 ♀♀, 1 ♂, 1 juvenile, site 9; 1 ♀, site 10. Body size.- ♀♀ 0.8-1.3 mm; ♂♂ 1-1.2 mm; juveniles 0.6- Temporal study (site 3): 4 ♀♀, 1 ♂, 1 juvenile, May 1998; 0.7 mm. 8 ♀♀, 3 ♂♂, 2 juveniles, September 1998; 4 ♀♀, 2 ♂♂

Thalassas, 29(1) · January 2013 29 PATRICIA ESQUETE, ROGER N. BAMBER, JUAN MOREIRA & JESÚS S. TRONCOSO

Table 1: Pycnogonid species found at ten sites (1 to 10) in the O Grove inlet in December 1996 showing densities per site (individuals/0.28 m2), total abundance, numerical dominance (D, %), seagrass species (Z. marina: M; Z. noltii: N) and values of selected environmental variables of seawater.

1 3 4 5 6 7 8 9 10 Total D Achelia echinata 6 37 11 - 3 7 2 6 - 72 31.0 Nymphon gracile - - 1 ------1 0.4 Callipallene brevirostris - - - 1 - - - - - 1 0.4 Callipallene emaciata - - - 3 - - - 3 3 9 3.9 Callipallene spectrum - - - 2 - - 2 - - 4 1.7 Callipallene tiberi - 10 2 40 1 - 14 10 8 85 36.6 Anoplodactylus petiolatus 2 ------2 0.9 Anoplodactylus pygmaeus 5 7 6 5 22 2 2 7 - 57 24.6 Endeis spinosa 1 ------1 0.4

Number of species 4 3 4 5 3 2 4 4 2 9 Total abundance 14 54 20 51 26 9 20 26 12 232

Seagrass M M M M/N N N M/N M/N M/N Depth (m) 0.6 5.9 0.3 0.3 0.3 0.3 0.3 0.3 0.3 pH 7.7 7.8 7.8 7.7 7.9 7.7 7.7 7.7 7.7 Temperature (ºC) 14.6 9.9 16.7 13.0 15.3 13.2 13.2 13.0 13.3 Salinity (‰) 29.0 32.0 32.5 30.0 30.5 20.0 33.0 33.0 32.0

(1 ovigerous), 1 juvenile, November 1998; 5 ♀♀, 5 ♂♂, 1 DISCUSSION juvenile, January 1999; 2 ♀♀, March 1999. The pycnogonid taxocoenosis found in the Zostera Body size.- ♀♀ 0.6-0.8 mm; ♂♂ 0.7 mm. meadows of the O Grove inlet comprises species typical of European shallow environments (Arnaud and Bamber, Distribution.- Atlantic, Mediterranean and Red seas. 1987). The studied Zostera meadows have a richer Iberian Peninsula: Cantabrian coast (Munilla, 1987), pycnogonid fauna than those present in other shallow Mediterranean coast (Pérez-Ruzafa and Munilla, 1992). habitats and sedimentary substrata in the Galician rías. For example, Moreira and Troncoso (2007) and Remarks.- One ovigerous male was found in September Cacabel os et al. (2009), using an identical methodology, 1998. only found two and four pycnogonid species in nearby inlets, respectively, and in much lower numbers. Family ENDEIDAE Norman, 1908 Likewise, extensive studies carried out in other European Genus Endeis Philippi, 1843 areas with salinity fluctuations have reported similar Endeis spinosa (Montagu, 1808) assemblages to those found in O Grove, but characterized by lower densities for most of the species (Wolff, 1976; Material examined.- Spatial study (December 1996): 1 Pérez- Ruzafa and Munilla, 1992, excepting Tanystylum ♀, site 3. Temporal study (site 3): 1 ♀, July 1998; 2 ♀♀, conirostre (Dohrn, 1881)). In general, hard substrata with September 1998; 1 ♀, November 1998; 1 ♂, January 1999. seaweed biocoenoses host more diverse assemblages (e. g. Munilla, 1991; Chimenz et al., 1993) than unvegetated Body size.- ♀♀ 1.8-2.2 mm; ♂♂: 2.3 mm. sedimentary bottoms which tend to be poor in pycnogonid faunas (Chimenz and Cotarelli, 1986; Pérez Ruzafa and Distribution.- Widespread Amphiatlantic species. Iberian Munilla, 1992; Chimenz et al., 1993). However, most Peninsula: Cantabrian Coast (Munilla, 1987), Ría de Vigo studies point out that pycnogonids are well represented (Anadón, 1975), Gibraltar (Munilla, 1993), Mediterranean in soft bottoms when covered by Posidonia oceanica coast (De Haro, 1965). (e. g. De Haro, 1967; Arnaud, 1988; Chimenz et al., 1993; Munilla León and San Vicente, 2000). Moreover, Remarks.- One specimen collected in July 1998 presented those have also been proposed as a “source” habitat for one leg of the third pair abnormally small, about ¼ of the pycnogonids to colonise adjacent habitats (Munilla and normal length. San Vicente, 2000).

30 Thalassas, 29(1) · January 2013 PYCNOGONIDS (ARTHROPODA: PYCNOGONIDA) IN SEAGRASS MEADOWS: THE CASE OF O GROVE INLET (NW IBERIAN PENINSULA)

Table 2: Pycnogonid species found in site 3 from May 1998 to March 1999, showing density per month (individuals/0.312 m2) for each species, total density and values of selected environmental variables of seawater.

1998 1999

May July September November January March Total Achelia echinata 14 36 63 42 34 25 214 Nymphon gracile 2 1 2 - 3 4 12 Callipallene emaciata - - 3 1 5 - 9 Callipallene spectrum - - 3 4 - - 7 Callipallene tiberi 4 1 2 1 - 3 11 Anoplodactylus pygmaeus 6 - 13 7 11 2 39 Endeis spinosa - 1 2 1 1 - 5

Number of species 4 4 7 6 5 4 7 Total abundance 26 39 88 56 54 34 297

Temperature (ºC) 21.5 25.2 20.1 17.2 21.2 12.4 pH 8.0 7.8 7.7 7.7 7.5 7.6 Salinity (‰) 32.0 34.7 40.4 40.8 32.7 41.0

The abundance of pycnogonids in O Grove showed in winter (Hasegawa et al., 2007). This coincidence of the great seasonal fluctuations, with the highest numbers maximal values of pycnogonid density and those of the of species and individuals in September and the lowest above-ground biomass of the seagrass can be explained by values in spring. Particularly, in the case of A. echinata, the subsequent increase of surface available for epiphytic the highest numbers and proportion of juveniles occurred algae, hydroids and bryozoans that occurs when leaves in July, followed by a substantial increase of the total are enlarged; these epiphytes, which bloom in August, abundance of the population in September. This indicates provide a significant increase in food resources (Böstrom a high rate of survival of juveniles during the summer. et al., 2006; Hasegawa et al., opus cit.) from which the Likewise, the population decreased in the following populations of pycnogonids may benefit, therefore reaching sampling periods coupled with a high number of juveniles; their greatest abundances after late summer. Similarly, this suggests, on the one hand, low rates of survival of the highest proportions and numbers of juvenile stages adults in autumn and, in the other hand, an ongoing coincide with this bloom of epiphytes, suggesting that recruitment of juveniles through autumn. In winter- the reproductive period occurs in the months previous to spring, the population reaches the minimum in total the maximum of food availability. Seasonal variations in numbers and percentage of juveniles, suggesting that abundances of secondary producers in seagrass meadows, the conditions are not favourable for reproduction and linked to the life history of the plant and abundance of survival. These results are similar to those found by Jarvis epiphytic food-species has been verified for a number and King (1978), who pointed out that juvenile stages of benthic taxa (e. g. Edgar, 1990; Böstrom et al., 2006). of A. echinata appear in April and reach a maximum Indeed, previous studies in the O Grove meadows have also in August. In contrast, Munilla León (1980) found a shown similar fluctuations for gastropods, bivalves and maximum of juveniles in April, and minimum values in several polychaete families (Quintas, 2005), isopods and August-September, and suggested that such differences amphipods (Esquete et al., 2011). between different populations of the same species are due to variations in environmental conditions. In conclusion, the present study suggests that the presence of the seagrass favours the availability of food The temporal dynamics of A. echinata in particular resources for pycnogonids, thereby allowing a higher (Figure 2) and that of the whole pycnogonid taxocoenosis diversity than in other non-vegetated habitats. Similarly, in general (Table 2) seems to be coupled with the life cycle the seasonal evolution of the Zostera meadow would of Z. marina; thus, the seagrass shows elongation of leaves entirely determine the seasonal variations in diversity and and rhizomes in spring-summer and dispersion of seeds abundance of the pycnogonids.

Thalassas, 29(1) · January 2013 31 PATRICIA ESQUETE, ROGER N. BAMBER, JUAN MOREIRA & JESÚS S. TRONCOSO

ACKNOWLEDGEMENTS De Haro A (1967). Relaciones entre Picnogónidos e Hidroideos en el medio posidonícola. Boletín de la Real Sociedad The authors are grateful to the members of the Española de Historia Natural (Biología), 65: 301-303. Adaptaciones de Animales Marinos group (Universidade Edgar G (1990). Population regulation, population dynamics de Vigo) for their help with sampling collection and and competition amongst mobile epifauna associated with especially to P. Quintas for the sorting of samples. This seagrass. Journal of Experimental Marine Biology and work was supported by the Xunta de Galicia (grant Ecology, 144 (2-3): 205-234. number XUGA 30101A98). Constructive comments from Esquete P, Moreira J, Troncoso JS (2010). First record of two anonymous referees are acknowledged. Perioculodes aequimanus (Crustacea: Amphipoda) in the north-east Atlantic, with remarks on taxonomic characters. REFERENCES Marine Biodiversity Records, e112: 1-7. Esquete P, Moreira J, Troncoso JS (2011). Peracarid assemblages Anadón R (1975). Contribución al conocimiento de la fauna of Zostera meadows in an estuarine ecosystem (O Grove inlet, bentónica de la ría de Vigo (NW de España). I. Picnogónidos NW Iberian Peninsula): spatial distribution and seasonal y Crustáceos de Panjón. Investigación Pesquera, 39 (1): variation. Helgoland Marine Research, 65: 445-455. 199-218. Genzano GN (2002). Associations between pycnogonids and Arango CP, Wheeler WC (2007). Phylogeny of the sea spiders hydroids from Buenos Aires littoral zone, with observations (Arthropoda: Pycnogonida) based on direct optimization of on the semi-parasitic life cycle of Tanystylum orbiculare six loci and morphology. Cladistics, 23: 253-293. (Ammotheiidae). Scientia Marina, 66 (1): 83-92. Arnaud F (1988). Les Pycnogonides (Chelicerata) de Hasegawa N, Hori M, Mukai H (2007). Seasonal shift in seagrass Méditerranée Distribution écologique, bathymetrique et bed primary producers in a cold temperate estuary: dynamics biogeographie. Mésogée-Bulletin du Muséum D’Histoire of eelgrass Zostera marina and associated epiphytic algae. Naturelle de Marseille, 47 : 37-58. Aquatic Botany, 8: 337-345. Arnaud F, Bamber RN (1987). The biology of the Pycnogonida. Hasegawa N, Nori M, Mukai H (2008). Seasonal changes in Advances in Marine Biology, 24: 1-96. eelgrass functions: current velocity reduction, prevention Bamber RN (2007). A holistic re-interpretation of the phylogeny of sediment resuspension and control of sediment-water of the Pycnogonida Latreille, 1810 (Arthropoda). Zootaxa, column nutrient flux in relation to eelgrass dynamics. 1668: 295-312. Hydrobiologia, 596: 387-399. Bamber RN (2010). Sea-Spiders (Pycnogonida) of the north-east Jarvis JH, King PE (1978). Reproductive biology of British Atlantic. In: Synopses of the British Fauna (New Series). Pycnogonids (oogenesis and reproductive cycle). Zoological JH Crothers, PJ Hayward, eds, Second edition, Vol. 5, Field Journal of the Linnean Society of London, 63 (1-2): 105-131. Studies Council, Linnean Society of London, London, 249 Montaudouin X de, Sauriau P-G (2000). Contribution to a pp. synopsis of marine species richness in Pertuis Charentais Bamber RN, Davis MH (1982). Feeding of Achelia echinata Sea with new insights in soft-bottom macrofauna of the Hodge (Pycnogonida) on marine algae. Journal of Marennes-Oléron Bay. Cahiers de Biologie Marine, 41: Experimental Marine Biology and Ecology, 60: 181-187. 181-222. Böstrom C, Jackson EL, Simenstad CA (2006). Seagrass Moreira J, Troncoso JS (2007). Inventario de la macrofauna landscapes and their effects on associated fauna: a review. bentónica de sedimentos submareales de la Ensenada Estuarine, Coastal and Shelf Science, 61: 111-123. de Baiona (Galicia, NO Península Ibérica). Nova Acta Cacabelos E, Gestoso L, Troncoso JS (2009). Inventario de la Científica Compostelana (Bioloxía), 16: 101-128. macrofauna bentónica de sustratos blandos de la Ensenada Munilla T (1981). Contribució al coneixement de la distribució de San Simón (NO España). Boletín de la Real Sociedad ecológica deis Picnogonids catalans de la Costa Brava. Butlletí Española de Historia Natural Sección Biología, 103 (1-4): de la Institució Catalana d’Història Natural, 47 (4): 77-86. 103-11 Munilla T (1987). Picnogónidos costeros del norte de España. Chimenz C, Cottarelli V (1986). Soft bottom Pycnogonida from Miscelanea Zoologica, 11: 369-373. the gulf of Salerno (Italy). Oebalia, 23: 137-143. Munilla T (1988). Premiers pycnogonids côtiers du détroit de Chimenz C, Tosti M, Cottarelli V (1993). Taxonomical and Gibraltar (Coté Iberique). Butlletí de la Institució Catalana ecological observations on Pycnogonida from Apulian d’Historia Natural, 55: 59-65. coasts (southern Italy). Italian Journal of Zoology, 60 (3): Munilla T (1991). Picnogónidos litorales recogidos sobre el 339-347. alga Mesophyllum lichenoides en Nerja (Málaga, Mar de De Haro A (1965). Picnogónidos de la fauna española. Comunidad Alborán). Orsis, 6: 95-99. de Picnogónidos en el alga parda Halopteris scoparia (L). Munilla T (1993). Pycnogonids from southern Spain: Fauna I Boletín de la Real Sociedad Española de Historia Natural project. Journal of the Marine Biological Association of the (Biología), 63: 213-218. United Kingdom, 73: 543-553.

32 Thalassas, 29(1) · January 2013 PYCNOGONIDS (ARTHROPODA: PYCNOGONIDA) IN SEAGRASS MEADOWS: THE CASE OF O GROVE INLET (NW IBERIAN PENINSULA)

Munilla León T (1980). Desarrollo anual y reproducción de Roberts D (1981). Pycnogonids from Strangford Lough, Northern Achelia echinata Hodge, 1864 (Pycnogonida). Cahiers de Ireland. Irish Naturalists’ Journal, 20 (5): 189-192. Biologie Marine, 21: 115-121. Sánchez E, Munilla T(1989). Estudio ecológico de los primeros Munilla T, Nieto D (1999). Littoral pycnogonids from the Picnogónidos litorales de las Islas Canarias. Cahiers de Chafarinas islands (Alboran sea, Western Mediterranean). Biologie Marine, 30 (1): 49-67 Vie et Milieu, 49 (2-3): 155-161. Soler i Membrives A, Turpaeva E, Munilla T (2009). Pycnogonids Munilla León T, San Vicente C (2000). Suprabenthic pycnogonids of the eastern Weddell Sea (Antarctica) with remarks on from Creixell Beach (Tarragona, West Mediterranean). their bathymetric distribution. Polar Biology, 32 (9): 1389- Cahiers de Biologie Marine, 41 (3): 321-328. 1397. Pérez-Ruzafa A, Munilla T (1992). Pycnogonid ecology in the Wolff WJ (1976). Distribution of Pantopoda in the estuarine area Mar Menor (Murcia, SW Mediterranean). Scientia Marina, in the Southwestern part of the Netherlands. Netherlands 56 (1): 21-28. Journal of Sea Research, 10 (4): 472-478. Quintas P (2005). Distribución especial y temporal de los Wyer D, King PE (1974). Feeding in British littoral Pycnogonids. moluscos y anélidos poliquetos en las praderas de Zostera Estuarine and Coastal Marine Studies, 2: 177-184. marina L. y Zostera noltii Hornem. de la ensenada de O Grove (Galicia, España). Tesis Doctoral, Universidade de Vigo, Vigo.

(Received: September 14, 2012; Accepted: October 30, 2012)

Thalassas, 29(1) · January 2013 33

Thalassas, 29(1) · January 2013: 35-58 An International Journal of Marine Sciences

SEASONAL DYNAMICS OF THE PHYTOPLANKTON COMMUNITY IN THE GANDIA COASTAL AREA, SOUTHERN GULF OF VALENCIA

I. GADEA(1), M. RODILLA(1), J. SOSPEDRA(1), S. FALCO(1), T. MORATA(1)

(1) Institut d’Investigació per a la Gestió Integrada de Zones Costaneres (IGIC), Universitat Politècnica de València, C/Paranimf 1, 46730 Grau de Gandia, Spain

ABSTRACT Seasonal variability in the phytoplankton community of the coastal area of Gandia in the south of the Gulf of Valencia (Western Mediterranean Sea) was exam- ined in relation to physical and chemical surface water variables (i.e. salinity, nutrients, dissolved oxygen and temperature). This small area presents most of the point and non-point nutrients inputs that affect coastal areas as wastewater discharges through submarine outfall, river discharges and groundwater discharges from a detritic aquifer. Furthermore, surface channels that drain the Safor wetland, which is used mainly for agricultural crops, outflow into the confined har- bour. The main objective of the study was to observe the variations in phytoplankton groups as a response to environmental variables during different seasons and understand which species could be used as indicators of anthropogenic pressure. For this purpose, the taxonomic composition of the micro-phytoplankton communities at 32 fixed stations was determined in four sampling campaigns from summer 2010 to spring 2011. The results indicate that nutrient inputs mainly from the Serpis river and channels that drain the Safor Wetland determine the composition and abundance of the phytoplankton community, and that several key environmental factors such as water temperature, radiation, nutrients, and the molar ratios of nutrients influence seasonal phytoplankton assemblages. However, the discharge of effluent from a sewage treatment plant through the submarine outfall did not appear to have a significant impact on the phytoplankton community. The phytoplankton community comprised two main groups: diatoms and dinoflagellates and a total of 108 taxa were identified. The diatom population primarily flourished in autumn and winter whereas in spring, dinoflagellate bloom occurred with high radiation, very low DIP and high DIN:DIP and low DSi:DIN molar ratios. In this paper we discuss the possible rationale for these nutrient changes. Furthermore, potentially blooming species were detected in the Gandia harbour and in the mouth of the Serpis river at Venecia Beach.

Key words: Phytoplankton, nutrients, eutrophication, seasonality, Western Mediterranean.

RESUMEN (Variabilidad estacional de la comunidad de fitoplancton de las aguas superficiales de la zona costera de Gandía en el sur del Golfo de Valencia) La variabilidad estacional de la comunidad de fitoplancton de las aguas superficiales de la zona costera de Gandía en el sur del Golfo de Valencia (Mediterráneo occidental) fue examinada, teniendo en cuenta su relación con diferentes variables físicas y químicas (p.e. salinidad, nutrientes, oxígeno disuelto, temperatura, etc.). En esta pequeña área se dan la mayoría de las entradas de nutrientes, tanto puntuales como difusas, que afectan las áreas costeras: descargas de aguas resi- duales mediante emisarios submarinos, aportes fluviales y descargas de aguas subterráneas procedentes de acuíferos costeros. Además, los canales superficiales que drenan el humedal de La Safor, cuyo uso fundamental es la agricultura, vierten en las aguas confinadas del puerto. El objetivo principal de este estudio fue observar las variaciones de los grupos de fitoplancton como respuesta a las variaciones ambientales en diferentes estaciones del año, y determinar que especies pueden ser utilizadas como indicadores de presión antrópica. Para ello, se determinó la composición taxonómica de la comunidad de micro-fitoplancton en 32 puntos de muestreo fijos en cuatro campañas de muestreo, desde verano de 2010 hasta primavera de 2011. Los resultados muestran que la entrada de nutrientes, principalmente a través del Río Serpis y los canales que drenan el humedal, determinan la composición y abundancia de la comunidad de fitoplancton. Además diversos factores ambientales clave como temperatura del agua, radiación, nutrientes, así como las relaciones entre nutrientes influyen en las diferentes asocia- ciones de fitoplancton observadas en cada estación. Por otro lado, la descarga del efluente procedente de la depuradora de aguas residuales no tuvo un impacto significativo sobre la comunidad de fitoplancton. La comunidad de fitoplancton estuvo formada principalmente por dos grupos: diatomeas y dinoflagelados. Se identificaron un total de 108 taxones. Las diatomeas proliferaron principalmente en otoño e invierno. Los dinoflagelados proliferaron en primavera, bajo condiciones de elevada radiación, baja concentración de DIP, razones DIN:DIP elevadas y razones DSi:DIN bajas. En este documento se discute la justificación de los cambios en la concentración de nutrientes. Además, se detectaron especies potencialmente nocivas en el Puerto de Gandía y en la desembocadura del río Serpis, en la playa de Venecia.

Palabras clave: Fitoplancton, nutrientes, eutrofi zación, estacionalidad, Mediterráneo Occidental

Thalassas, 29(1) · January 2013 35 I. GADEA, M. RODILLA, J. SOSPEDRA, S. FALCO & T. MORATA



 S2 S2'-S B2-S C3-S E2-S F2-S 0 S2'-B

B2-B

C3-B 10 DEPTH (m) E2-B F2-B 20 0 500 1000 1500 2000 2500 3000 3500 DISTANCE (m)

Figure 1: Sampling site in the south of the Gulf of Valencia (Western Mediterranean Sea). Sample sites distribution through the transect.

INTRODUCTION dynamics are the result of a complex interplay of physi- cal, chemical and biological processes (Choudhury and Phytoplankton biomass remains relatively low Pal, 2010). In coastal and shelf waters particularly, throughout most of the Mediterranean coastal areas plankton abundance and species composition are char- (Yilmaz et al., 1992; Duarte et al., 2000; Drira et al., acterized by a very high degree of spatial and temporal 2010). The quality of coastal waters in many regions of variability (Ribera d’Alcalá et al., 2004), and these the world has deteriorated in recent years as human popu- reflect the environmental conditions of the ecosystem, lation and activities have increased along coastal regions among which nutrient availability plays a significant role (Newton et al., 2003). On the Mediterranean Sea, this (Beman et al., 2005; Puigserver et al., 2010). The role of human pressure is responsible for major changes in coast- nutrients, especially nitrogen and phosphorus as limiting al ecosystems (Duarte et al., 1999, 2000), particularly in factors of phytoplankton, is an important aspect of any areas with excessive nutrient loading and/or restricted attempt to mitigate and manage eutrophication (Conley, water exchange. Elevated inputs of nutrients can produce 2000; Conley et al., 2009; Paerl, 2009). A comprehensive eutrophication (Newton et al., 2003) with its associated understanding of how nutrients affect phytoplankton problems, such as harmful algal blooms and deterioration growth, diversity, and production, is therefore needed of water quality (Domingues et al., 2011). Phytoplankton to properly assess the impact of nutrient enrichment and

36 Thalassas, 29(1) · January 2013 SEASONAL DYNAMICS OF THE PHYTOPLANKTON COMMUNITY IN THE GANDIA COASTAL AREA, SOUTHERN GULF OF VALENCIA

Figure 2: Vertical profiles of temperature and salinity. the efficiency of subsequent nutrient reduction strategies Vaca intermittent watercourse which outflows, directly (Gobler et al., 2006; Domingues et al., 2011). to the sea, on the Ahuir beach (Sebastiá et al., 2012). The hydrology of this wetland is manipulated to satisfy The North Western Mediterranean has a very dense the different cultivation needs and these discharges are human population (100 habitants/m of coastline in some characterized by high nitrogen loads due to intensive regions); therefore, near-shore waters are very susceptible agriculture practices (mainly citriculture). The nitrogen to anthropogenic alterations (Olivos et al., 2002). Siokou- in these fertilisers seeps into ground water, rivers, and Frangou et al., (2010) consider that the Catalan front is an streams, gradually making its way into coastal waters area of higher nutrient availability and intense biological (Newton et al., 2003). An important source of nitrogen and activity. In this area,cyanobacteria and picoeukaryotes phosphorus is the sewage plant that treats the municipal often coexist or alternate with diatoms, dinoflagellates and wastewater of Gandia which discharges treated wastewater other flagellates belonging to different algal groups. In the into the sea through a submarine out fall at an approximate Catalan Sea, the strong seasonality creates optimum con- distance of 1700 m from the coastline. ditions for changes in the alternance of dominant groups in the phytoplankton community (Siokou-Frangou et al., An other freshwater input is the Serpis river which 2010).Spatial and seasonal variability of primary produc- has a marked Mediterranean regime characterized by a tion values can be high (Granata et al., 2004, Siokou- dry period in summer and humid period with torrential Frangou et al., 2010). rains, mainly at the beginning of autumn (Garófano et al., 2009).This river is associated with important point The Gulf of Valencia, south of the Catalan Sea, has and diffuse pollution sources due to certain land uses and suffered from progressive eutrophication process that fires, respectively (CHJ, 2005; Garófano et al., 2011). has been accelerated in recent decades due to the strong The sewage plant of Gandia has two overflow channels industrial and demographic development of coastal cities that discharge directly to the river near the mouth, which (Soler and del Río, 1995). The coast of Gandia, located happens mainly during torrential rain episodes because in the south of Gulf of Valencia, has different freshwater wastewater and pluvial waters are not separate and in inputs: pumped water from the Safor Wetland is discharged summer as consequence of the increase in the population. through surface channels to Gandia Harbour and to the While the Vaca watercourse outflows in a more open

Thalassas, 29(1) · January 2013 37 I. GADEA, M. RODILLA, J. SOSPEDRA, S. FALCO & T. MORATA

Figure 3: Spatial and temporal variation of DIN (μmol l-1), DSi (μmol l-1), DIP (μmol l-1) and TP (μmol l-1). area, the Serpis River outflows on Venecia Beach, on the Studying the receiving waters is especially important southern side of Gandia Harbour and it is a semi-enclosed given the oligotrophic character of Mediterranean waters, bay (enclosed by the harbour and the river mouth). where discharges of freshwater and associated nutrients Furthermore, this coastal area receives a diffuse input of play a key role in marine productivity (Ludwig et al., freshwater and nutrients from the Plana Gandia-Denia 2009). Threat it faces from increased nutrient loading detritic aquifer through groundwater discharges that are from anthropogenic activities may be a cause for concern. rich in silicates (Sebastiá et al., 2012). This may imply a shift from oligotrophic to eutrophic

38 Thalassas, 29(1) · January 2013 SEASONAL DYNAMICS OF THE PHYTOPLANKTON COMMUNITY IN THE GANDIA COASTAL AREA, SOUTHERN GULF OF VALENCIA

status whose influence on the phytoplankton community is a analysis and for the phytoplankton counts were taken at interesting to evaluate. In the south of the Gulf of Valencia the surface layer (0.3 m depth) using a Van Dorn bottle. In (Western Mediterranean) and its coastal zone few studies order to study the vertical structure of the water column, have been carried out in relation to this topic: Rodrigo temperature and salinity were measured in five extra sam- et al., (2003) studied the phytoplankton community of ples above the bottom. These samples were taken in an the Safor Wetland and Sebastiá et al., (2012) studied the orthogonal transect (fig.1). abundance of phytoplankton groups using diagnostic pho- topigment analysis,the study was carried out specifically in Temperature and dissolved oxygen were measured in Gandia Harbour and only in spring and summer. However, situ with a YSI proODO sensor and light penetration was the phytoplankton community structure and dynamics in measured with Secchi disc. Water samples were kept in a relation to the physicochemistry of the Gandia coastal area cool box (4ºC) and transported to the laboratory. is still subject to investigations. Phytoplankton quantitative samples were placed The main objectives of this study was to analyze the in 0.125 l jars and fixed in situ with 20% formalde- variations in the phytoplankton community as a response hyde solution neutralized with hexametilenentramina to physical and chemical water variables during different (Throndsen, 1978). Sub-samples (50 ml) were allowed seasons in a coastal area with different inputs of nutrients to settle for 24h in HydroBios chambers and then count- and to understand which species could be used as indica- ed and identified at x400 magnifications with a Leica tors of anthropogenic pressure. To achieve this objective, DMIL inverted microscope (Utermohl, 1958). Counts it was necessary to study phytoplankton composition, sea- were made following the methodology of Andersen sonal variations of environmental variables and examine and Throndsen (2003). This did not include the small the possible relationship between the phytoplankton suc- size fraction of phytoplankton (picoplankton and some cessional patterns and the changes in nutrient and environ- portion of the nanoplankton). Qualitative phytoplankton mental regimen. The spatial patterns of the phytoplankton samples were collected by plankton nets (mesh size 50 community were studied using a cluster analysis and a μm). The phytoplankton community was classified to canonical correspondence analysis (CCA) was performed the lowest taxonomic level possible in accordance with to understand if there was any environmental factor that Tomas (1997). triggers the development of HABs. The following parameters were analysed in all the MATERIAL AND METHODS samples: salinity, chlorophyll-a (Chl-a) suspended solids (SS), nitrate, nitrite and ammonium, dissolved inorganic Study site, sampling and laboratory procedures phosphorus (DIP), total phosphate (TP) and dissolved silicate (DSi). Dissolved inorganic nitrogen (DIN) was Coastal area of Gandia is located in the Western calculated as the sum of nitrate, nitrite and ammonium. Mediterranean Sea, in the south of the Gulf of Valencia Nutrients were analysed using the method of Aminot (Spain). In this study, samples were taken from 33 sam- and Chaussepied (1983). Chl-a and SS were analyzed pling sites (fig.1) placed in parallel lines at different following the methodology described in APHA (2005). distances from the shoreline: surf zone (SZ), 200 m (A); Salinity was determined by means of a conductivity meter 600 m (B), 1000 m (C), 1300 m (D), 2000 m (E) and 4000 Multi 340i/SET WTW. m (F).The sampling sites formed a grid whose north and south limits were the mouths of the Vaca watercourse in the Precipitation, environmental temperature, wind speed Ahuir Beach (station WV) and the Serpis river in Venecia and direction, as well as radiation, were measured at the Beach (station RS), respectively. This grid included the weather station situated in the Royal Sailing Club of submarine outfall of the Gandia sewage treatment plant Gandia located in Gandia Harbour. (station OU) and Gandia Harbour (stations H1, H2), where the ephemeral San Nicolás watercourse and surface chan- Data processing and statistical analysis. nels that drain the Safor Wetland outflow. The depth of the study area varied from 1.3 m to 20 m. The phytoplankton community was analysed in terms of species richness and abundance, diversity (Shannon- Four samplings were carried out from summer 2010 Weaver diversity index) and evenness (Pielou) (Zar, 1984) to spring 2011. Specifically, 26 August, 21 October, 23 using the PC-ORD v.4 statistical package. The cluster February and 16 May, these samplings were designated as: analysis allowed the grouping of study sites according to Summer, Autumn, Winter and Spring monitoring, respec- their similarity in phytoplankton composition. Bray-Curtis tively. Samples for the physical, chemical and chlorophyll distance along with group average was used as a linkage

Thalassas, 29(1) · January 2013 39 I. GADEA, M. RODILLA, J. SOSPEDRA, S. FALCO & T. MORATA

Figure 4: Seasonal changes in the mean concentrations of nutrients, chl-a and main phytoplankton groups from two stations in the entrance of the harbour (□ H1, H2), Ahuir beach (∆ WV), submarine outfall (●OU ), river Serpis and Venecia Beach (◊ RS, S4, A4) and from rest of stations (■).

40 Thalassas, 29(1) · January 2013 SEASONAL DYNAMICS OF THE PHYTOPLANKTON COMMUNITY IN THE GANDIA COASTAL AREA, SOUTHERN GULF OF VALENCIA

method. A ranked triangular matrix of similarities was (p<0.05) than the other areas. In summer a thermal calculated for the stations using Bray-Curtis similarity stratification of the water column was observed (fig. matrices following log (x+1) transformations. 2), in surface samples the temperature was about 28 ºC while at the bottom,the temperature was 25 ºC. Salinity A non parametric one-way analysis of variance exhibited seasonal fluctuations and reached maximum (Kruskal-Wallis) was used to test differences in phys- values (37.37 ± 0.69 g kg-1; 37.29 ± 0.33 g kg-1) in the ic-chemical variables and phytoplankton composition dry seasons (summer and winter, respectively) whereas between sampling areas and seasons. This analysis was the lowest values (36.66 ± 1.63g kg-1; 36.75 ± 1.36 g kg-1) performed using STATGRAPHICS 5.1. were measured in the rainy seasons (autumn and spring). Minimum values were observed at the mouth of the Serpis Phytoplankton and nutrient maps were made using the river, the lowest values being registered in the rainy Surfer v. 8 program. The method of interpolation used was seasons. In the submarine outfall plume, the lowest values triangulation with linear interpolation. were observed in summer and autumn (36.6 g kg-1, 35.9 g kg-1, respectively). Freshwater discharges from the aquifer Spearman Rank correlation (Rs) analyses were per- were observed mainly in autumn (36.1 g kg-1 in the swash formed on environmental parameters (nutrients, molar area) (fig.2).Oxygen concentration reached maximum ratios, radiation, dissolved oxygen, water transparency, values in winter (9.65 ± 0.22 mg l-1) and minimum and salinity) and phytoplankton groups in order to examine values is summer (7.00 ± 0.14 mg l-1). In all monitoring significant relationship. This analysis was performed using campaigns there were significant differences (p<0.05) SPSS v.16. between the surf zone and the rest of the sample points. In summer, winter and spring, the surf zone registered lower The relationship between potentially harmful and concentrations but in autumn, oxygen in this zone was bloom forming species and environmental parameters higher. The average light penetration (7.58 ± 5.22 m) in was determined with the multivariate ordination methods summer was significantly higher (p<0.05) than in the other Canonical Correspondence Analysis (CCA) using the seasons. In all seasons light penetration increased from the PC.ORD v4 statistical package. Bloom forming species shoreline to stations located 4000 m away. Minimum pH were included as dependent variables and physicochemi- was (7.91 ± 0.06) in summer, while the highest value of pH cal variables were included as independent variables. The (8.20 ± 0.03) was measured in spring. statistical significance of the relationships was evaluated using Monte Carlo permutation tests. 2. Nutrients concentrations and nutrient molar ratios

Spearman Rank correlation (Rs) analyses were per- Seasonal and spatial variation of nutrient concentra- formed on environmental parameters (nutrients, molar tions is shown in figures 3 and 4. Nitrate was the most ratios, radiation, dissolved oxygen, water transparency, dominant nitrogen form in all seasons. The highest values and salinity) and phytoplankton groups in order to examine of ammonium were observed at the submarine outfall area significant relationship. This analysis was performed using and at the mouth of the river Serpis in summer. In this sea- SPSS v.16. son maximum values of nitrites were registered at the sub- marine outfall and the mouth of the river too. The highest Parameters shown in the tables have been calculated values of DIN were observed in summer (6.05 ± 6.59 μmol using Microsoft Office Excel. l-1) and spring (5.79 ± 6.24 μmol l-1), and were, in fact, significantly higher (p<0.05) than the values registered RESULTS in autumn and winter. In the study area, three zones pre- sented peaks of DIN: Gandia Harbour showed 36.52 μmol Physicochemical variables l-1 in summer, the submarine outfall plume reached 19.07 μmol l-1 in summer too, and the mouth of the river Serpis 1. Temperature, dissolved oxygen, salinity and light presented 17.02 μmol l-1 , 17.26 μmol l-1 and 21.54 μmol penetration. l-1 in summer, autumn and spring, respectively. In the same areas, the highest values of DSi were measured during the Data collected during the four seasons are shown in study period. Maximum values were observe dat the mouth table 1. The overall means of environmental parameters of the Serpis river in autumn and spring (28.11 μmol l-1 and show that water temperatures followed the expected 12.08 μmol l-1, respectively) and in the submarine outfall annual dynamics with winter minima (13.16 ± 0.40 ºC) plume in autumn (7.34 μmol l-1). In general, low DIP con- and summer maxima (27.30 ± 0.87 ºC). The surf zone, in centrations were observed throughout whole study, in fact, all seasons, registered significantly higher temperatures concentrations in the spring samples were undetectable.

Thalassas, 29(1) · January 2013 41 I. GADEA, M. RODILLA, J. SOSPEDRA, S. FALCO & T. MORATA

Autumn Summer 0.3% 1% 0.2% 4.5% 2% 0.05%

99% 93%

Winter 0.1% 1.5% Spring 5.5% 2.8% 2.2% 0% 0.1% 0.45%

3.5%

46% 48%

89%

Diatoms Dinoflagellates Raphydophytes Chlorophytes Euglenophytes Others

Figure 5: Contribution of different phytoplankton groups to abundance in each season.

The highest DIP concentrations were measured in summer were observed mainly at the surf zone and around the first (0.16 ± 0.28 μmol l-1). The submarine outfall area reached 100 meters from the coastline; the maximum concentra- maximum values, 1.06 μmol l-1, in summer and 1.84 tion measured was 11.71 μg l-1 in the Serpis estuary. In this μmol l-1,in autumn. Winter showed significantly higher season, the lowest values were register at the plume of the (p<0.05) TP values, however maximum concentrations outfall. In the other seasons, the highest values of Chl-a were registered at the submarine outfall plume in summer were observed on the mouth of the Serpis river too, but the and autumn (1.78 μmol l-1 and 1.91 μmol l-1, respectively). concentrations were always lower than those found in the winter monitoring. The criteria for stoichiometric nutrient limitation were the same as those used by Dotch and Whitledge (1992), Phytoplankton community structure Justic et al., (1995) and Olivos et al., (2002) to identify a nutrient-limited environment for elements based on nutrient A total of 108 different taxa were identified in this study uptake kinetics: P is limiting if DSi: PO4>22 and DIN: in different seasons (table 3a;3b), Dinophyceae (45%),

PO4>22; N is limiting if DSi: DIN>1 and DIN: PO4<10; and Diatoms (39%), Dictyochophytes (3%), Chloro-phytes

Si is limiting if DSi: PO4<10 and DSi: DIN<1. In general, (3%), Euglenophytes (2%), Haptophytes (2%), Raphy- phosphorus acted to a great extent as the potential limiting dophytes (2%), Cryptophytes (2%) and Chrysophytes nutrient (table 2) and silica acted as the limiting nutrient on (2%). In terms of species richness, dinoflagellates and the submarine outfall plume in summer and autumn and in diatoms were the most important groups. Dinoflagellates more than 30% of the cases in winter. Nitrogen as a limiting were the largest group with respect to the total number nutrient acted only in two samples located 4000m from the of taxa identified (49 species were identified) which coast, in summer. In autumn,33.3 % of cases did not present belonged to 24 different genera. The most representa- limiting nutrient (table 2). tive dinoflagellate genera were Protoperidinium and Ceratium with 11 and 10 species respectively. The diatom 3. Total chlorophyll a species identified belonged to 36 genera. The most repre- sentative diatom genus was Chaetoceros with 7 species. Chl-a concentration showed significantly higher val- Only 32 taxa had a frequency higher than 10% of the ues (p<0.05) in winter (2.55 ± 2.54 μg l-1) and lower in samples. Most of these taxa were diatoms, followed by summer (0.03 ± 0.08μg l-1) In winter, the highest values dinoflagellates and raphydophytes.

42 Thalassas, 29(1) · January 2013 SEASONAL DYNAMICS OF THE PHYTOPLANKTON COMMUNITY IN THE GANDIA COASTAL AREA, SOUTHERN GULF OF VALENCIA

Figure 6: Box-whiskers diagram of phytoplankton groups.

The most dominant group was diatoms in terms of Venecia Beach and mainly, at the entrance of the harbour, abundance,and the most dominant species were the dia- the diatoms Guinardia delicatula and Pseudo-nitzschia toms Bacillaria paxillifera and Pseudonitzschia spp (>500 spp registered the highest values. The dinoflagellates of x 103 cells l-1 in total phytoplankton). The most dominant the genera Scrippsiella appeared all over the area, except in frequency were Proboscia alata, Pseudonitzschia spp at the submarine outfall, and they registered the highest (72 % and 56 % occurrence respectively), Cylindrotheca values at the entrance of the harbour. The euglenophyte closterium and Chaetoceros affinis appeared in more than Eutreptiella gimnastica only appeared at the entrance of 50% of the samples. In contrast, Asterionellopsis glacialis the harbour and Venecia Beach. Odontella mobiliensis was had a low frequency (29% occurrence) but contributed in only observed in the mouth of the rivers, mainly in the an important way to the density of total phytoplankton Serpis river and the genera Chatonella appeared mostly at (>200 x 103 cells l-1 in total phytoplankton). Dinoflagellates the submarine outfall and in the mouth of the Serpis river. were not dominant in terms of abundance; the most On the other hand, Octactis octonaria, Gossleriella tropica abundance genus was Heterocapsa having 21 x 103 cells and Noctilluca scintillans were only observed at the station l-1 in total phytoplankton, although it was not the most control (F1) located at 4000 m from the shoreline. dominant in terms of frequency (25% of occurrence). The most frequently occurring dinoflagellates were the genera 1. Seasonal dynamics of phytoplankton community Gymnodinium and S crippsiella (53% and 44% respective- ly). Raphydophytes showing a 53% occurrence, but did not In general,the highest values of cell abundance were contribute greatly to the abundance of total phytoplankton. registered in autumn (fig.6) with median abundance of Finally, euglenophytes appeared frequently during the around 9 x 103 cells l-1. Generally the lowest values of cell study (>50 % occurrence) but had a total cell abundance abundance were registered in summer and spring with a lower than 10 x 103 cells l-1. median of 880 cells l-1 and 2.240 cells l-1, respectively. On the other hand, the highest cell abundance value was The study of the phytoplankton community in the registered in summer, specifically in the southern half areas with higher human pressure (table 4) showed that at of the Serpis estuary, with 492.620 cells l-1. In general,

Thalassas, 29(1) · January 2013 43 I. GADEA, M. RODILLA, J. SOSPEDRA, S. FALCO & T. MORATA

Figure 7: Dendrogram for the hierarchical clustering of the 33 stations using group-average linking of Bray-Curtis similarities calculated on log-transformed abundance data. the temporal distribution of cell abundance coincided was diatoms (93%) followed by raphydophytes (4.5%) with temporal distribution of diatoms, which indicates and dinoflaglellates (2%) (fig. 5). The most frequently that this group was responsible for the variability of occurring species were Thalassionema nitzschioides, cell concentration. In fact, there was a strong significant Asterionellopsis glacialis and Pseudo-nitzschia spp., correlation (R2=0.90 p<0.01) between diatom abundance and these contributed greatly to the density of total and total abundance of cells. There was a high variability phytoplankton. The most frequent and abundant genera in cell abundance when the temporal distribution of of dinoflaglellates were Scrippsiella and Gymnodinium. main groups of phytoplankton was examined. Generally, The percentage of diatoms decreased in winter (89%) diatoms registered the highest values in autumn (fig. 6). while the percentage of raphydophytes, dinoflagellates Dinoflagellates and chlorophytes abundance in spring and euglenophytes increased. The most abundant and was significantly (p<0.05) higher than the other seasons. frequent species was Chaetoceros affinis,while the most Euglenophytes cell density was significantly (p<0.05) abundant dinoflagellate genus was Scrippsiella and the lower in summer and raphydophytes were more abundant most frequent was Gymnodinium. The relative abun- in autumn and winter than in spring and summer. dances of different groups were significantly different in spring compared to other seasons, the group with the In summer (fig.5), the plankton flora was represented highest relative abundance was the dinoflagellates with mainly by diatoms which represented 99% of cell abun- 48%; diatoms accounted for 46%, and chlorophytes and dance. The most dominant taxa in terms of abundance euglenophytes 2.8% and 2.2%, respectively. The most were Bacillaria paxillifera, Pseudo-nitzschia spp. and abundant species was the diatom Bacillaria paxillifera Guinardia delicatulaand in terms of frequency, Bacillaria but the most frequently occurring species were the dino- paxillifera, Proboscia alata and Rhizosolenia sp. The flagellates of the genus Gymnodinium followed by the genera Gymnodinium was the most abundant dinoflagel- genera Heterocapsa and Scrippsiella. Spring monitoring late in this season. In autumn, the most dominant group had significantly (p<0.05) higher values of diversity (2.03

44 Thalassas, 29(1) · January 2013 SEASONAL DYNAMICS OF THE PHYTOPLANKTON COMMUNITY IN THE GANDIA COASTAL AREA, SOUTHERN GULF OF VALENCIA

± 0.44 bits individuals-1) and evenness (0.43 ± 0.09) than I) registered lower cells abundance (1114 ± 400 cells l-1) the other seasons. In the case of species number, the high- than the rest of the area (group II) (3319 ± 1942 cells l-1), est values were registered in autumn and spring (14.12 ± as a result of the lower concentrations of dinoflagellates 4.00 individuals; 14.68 ± 4.31 individuals, respectively). observed in group I. The highest abundances of chloro- phytes and dinoflagellates were observed at the entrance 2. Spatial patterns of phytoplankton community. of the harbour (fig.9).

The hierarchical cluster showed that different spatial 3. Potentially harmful and bloom forming species. patterns existed according to the season (fig.7 and fig. 8)). In summer, there were significant differences (p<0.05) Thirty-one identified taxa could potentially lead to in the phytoplankton community among stations located harmful effects (e.g. toxic, fish-killing, or bloom form- nearer the coast up to 1000 m from the shoreline (Group ing). These taxa and their characteristics are shown I,except A5) compared to stations more than 1000 m from in table 5. Among them, 12 species are included in the shoreline (Group II). Group I presented significantly the Intergovernmental Oceanographic Commision (IOC) higher values of abundance, richness, diversity and even- Taxonomic Reference List of Harmful Micro Algae 2009; ness. In terms of density two zones registered a significant- specifically, 8 dinoflagellates, 2 diatoms, 1 euglenophyte ly higher (p<0.05) cell abundance within Group I:Gandia and 1 haptophyte. Higher cell abundance and recurrence Harbour (H1) 419 x 103 cellsl-1 and the Serpis mouth (RS y of dinoflagellates (Alexandrium sp., Gymnodinium spp. A4) 19770 ± 1930 cellsl-1. Within Group II, the area south Heterocapsa spp. Scrippsiella spp., Noctilluca scintillans, of the breakwater (C5, D5) and in the south of the river- Prorocentrum micans and Prorocentrum triestinum) were mouth (A5) represented a further subdivision due to their observed in spring. Among them, the genera Heterocapsa higher values of cell abundance, mainly in A5 (492 x 103 and Scrippsiella were the most abundant, reaching concen- cells l-1) and the presence of the genus Pseudo nitzschia. trations as high as 2 x 106 cells l-1 in the harbour, but the most frequent species were the dinoflagellates of the genus In autumn (fig.8), the surf area (group I) showed Gymnodinium. greaterdiversity and evenness furthermore dinoflagellates density was significantly higher (p<0.05). The surf area Generally harmful diatoms registered their highest had a lower density (5172 ± 1068 cells l-1) than the other abundance and occurrence in autumn and winter Pseudo- stations (12293 ± 6895 cells l-1). Chlorophytes appeared nitzschia spp. presented the highest percentage of occur- mainly in the mouth of the Serpis river (160 cellsl-1). The rence (91.7%) in autumn but reached the highest concentra- mouth of the Vaca watercourse had greater densities of dia- tion in summer (>400 x 103 cells l-1). The largest densities toms (47720 cells l-1) and dinoflagellates (840 cells l-1) than of this diatom were always observed in the surroundings of the rest of the study area. Dinoflagellates appeared mainly the harbour. A clear temporal pattern of the haptophyte of in and around the harbour area and at Ahuir Beach (fig.9). genus Phaeocystis. was not found from this data.

Winter monitoring showed two different groups The results of the Canonical Correspondence Analysis (fig.8).The mouth of the Vaca and the Serpis river and (CCA) are displayed in figure 10. The CCA analysis was Venecia Beach (group I) showed significantly higher performed with the most abundant potentially harmful values of diversity and evenness; on the other hand, and bloom-forming species detected. The environmental these areas registered lower cell abundances (2500 variables (temperature, radiation, precipitation, light pen- ± 551 cell.l-1) than the rest of the study area (group etration, nitrites, nitrates and dissolved oxygen) explained II) (5390 ± 3270 cells l-1) Diatom and raphydophyt- 31 % of the variance. Potentially harmful and bloom edensity was significantly higher (p<0.05) in Group II forming species can be divided into two main groups: than in Group I and euglenophytes and chlorophytes the first group comprising potentially harmful diatoms groups were more abundant in Group I than in group and the second comprising potentially harmful dinoflag- II. Dinoflagellates appeared mainly at the entrance of ellates. Abundance of potentially harmful diatoms was the harbour and in the southern part of the mouth of the higher in waters with a high nitrate concentration and Serpis river (group II.I) (fig.9). was inversely correlated with radiation and temperature. Among the potentially harmful diatoms, Pseudo-nitzschia In spring (fig. 8), it was difficult to establish a pattern spp showed a positive correlation with a high nitrite con- of spatial distribution; the hierarchical cluster showed two centration. Potentially harmful dinoflagellate abundance groups with significant differences (p<0.05) in terms of was higher at high radiation and was positively correlated density but not in terms of richness, diversity and even- with dissolved oxygen and precipitations events before ness. The Ahuir Beach and the submarine outfall (group the monitoring. Eutreptiella gimnastica was positive cor-

Thalassas, 29(1) · January 2013 45 I. GADEA, M. RODILLA, J. SOSPEDRA, S. FALCO & T. MORATA

Figure 8: Distribution of the main phytoplankton groups identified by the cluster analysis.

46 Thalassas, 29(1) · January 2013 SEASONAL DYNAMICS OF THE PHYTOPLANKTON COMMUNITY IN THE GANDIA COASTAL AREA, SOUTHERN GULF OF VALENCIA

related with precipitation event before monitoring and rainy seasons due to the increase in the flow caused by dissolved oxygen. Guinardia delicatula was the most precipitation. Minimum values were also recorded at the opportunistic species and Prorocentrum minimum and submarine outfall plume in summer and autumn. This was Prorocentrum lima had no clear pattern. a consequence of the increased flow in summer due to the population increase because it is a popular tourist destina- Relations between abiotic parameters and phytoplankton tion, and in autumn because rain water arrives at the sew- community. age treatment plant via the sewer system and then to the sea through the submarine outfall. Spearman Rank correlation analyses were performed on environmental parameters (water temperature, nutri- On the Gandia coast, during the study period, nutri- ents, radiation, water transparency, dissolved oxygen and ent concentrations (0.80- 36.52 μM for DIN, 0.03 - 28.11 salinity) and phytoplankton groups in order to examine μM for DSi, <0.01-0.32 μM for DIP) were below those significant relationships (table 6). The assessment of of typical nutrient-enriched areas such as, San Francisco the correlation was based on the scale defined by Torres Bay (Cloern, 1996) and Ria Formosa (Newton et al., 2003; (2004). Diatoms group showed significantly weak positive Brito et al., 2010) and Arenys de Mar harbour (Vila et correlations with Si and DIP and with DSi:DIN molar ratio, al., 2005); and slightly higher than those observed in the and they had moderately negative correlations with solar Catalan Sea by Olivos et al., 2002. Among the three nutri- radiation and water temperature. Dinoflagellates presented ents, DIP concentrations were particularly low, in the same a moderately positive correlation with solar radiation and order of magnitude as those measured in non-polluted weak correlation with DIN:DIP and DSi:DIP molar ratios. coastal areas (Aminot and Chaussepied, 1983; Glé et al., On the other hand, they showed a weak negative correla- 2008; Sebastiá et al., 2012) and slightly lower than those tion with DIP and DSi:DIN molar ratio. Chlorophytes were recorded by Olivos et al., (2002). weakly inversely correlated with salinity, DIP and light penetration and presented a weak positive correlation with The highest values of DIN and DSi were observed solar radiation, DIN, DSi and DIN:DIP and DSi:DIP molar at the mouth of the Serpis and in Gandia harbour (fig.4), ratios. Euglenophytes showed weakly positive correlations mostly in the rainy seasons when, as pointed out by with DSi and DSi:DIN and DSi:DIP molar ratios and they Sebastiá et al. (2012) precipitation events lead to ter- were weak inversely correlated with salinity and light pen- restrial runoff and increased river flow and also when the etration. Raphydophytes showed negative correlation with water from Plana Gandia-Denia aquifer, rich in nitrates solar radiation and weak with water temperature. and DSi, is pumped through the irrigation channels to the harbour to decrease the phreatic level and prevent Phytoplankton cell abundance had a weak positive crop root asphyxia. Thus, the major sources of DIN and correlation with Si and DSi:DIN molar ratio, and this DSi in this coastal area, are probably from the Serpis was weakly inversely correlated with water temperature, river and the channels that drain the Safor Wetland. radiation and salinity. Finally, Chl-a showed a moderately In addition to the previous inputs, a diffuse input of positive correlation with dissolved oxygen and weak cor- freshwater and nutrients is possible, in the swash area, relation with TP and DSi:DIP molar ratio and a weak nega- from the Plana Gandia-Denia detritic aquifer through tive correlation with light penetration. groundwater discharges rich in silica and nitrates (Sebatiá et al., 2012), mainly in autumn (fig.2).According to DISCUSSION Ballesteros-Navarro (2003), the Ahuir Beach, which is located at the end of Gandia’s urban area, receives a The results showed that the coastal area of Gandia is discharge from the Plana Gandia-Denia detritic aquifer, characterized by a high temporal and spatial variability of quantified at 66 Hm3 year-1 (2.1 m3s-1). Due to continued physicochemical parameters. These changes were particu- agricultural practices, nitrate levels in the detritic aquifer larly striking during the rainy seasons (autumn and spring), have exceeded the limit of 50 mg l-1 established by the which can be explained mainly by the contribution of the Nitrates Directive (Directive 91/676/EEC). On the other Serpis river, surface channels that drain the Safor Wetland hand, wetland species of Graminae are characterised by and the submarine outfall discharges. high silica content (typically 10-15% dry shoot weight). This biogenic silica, after decomposition of organic mate- Salinity exhibited seasonal fluctuations (fig. 2) and rial, remains in the soil and it is lixiviated to the aquifer reached maximum values in the dry seasons (summer (Conley 2002). Although, the natural vegetation surface and winter) whereas the lowest values were measured in has decreased recent decades, it still remains an important the rainy seasons (autumn and spring). Minimum values soil use. Thus, biogenic silica is an important element in appeared at the mouth of the Serpis River, mainly in the the terrestrial biogeochemical cycle, and must be taken

Thalassas, 29(1) · January 2013 47 I. GADEA, M. RODILLA, J. SOSPEDRA, S. FALCO & T. MORATA

Figure 9: Seasonal changes in the main phytoplankton groups from two stations in the entrance of the harbour (□ H1, H2), Ahuir beach (∆ WV), submarine outfall (●OU ), river Serpis and Venecia Beach (◊ RS, S4, A4) and from rest of stations (■). into account in addition to the chemical weathering of Domingues et al., 2011). The Mediterranean Sea has land silicates. Unlike DIN and DSi, in our study the sup- usually been considered a P-limited basin although a ply of DIP by these sources was not particularly appar- review of the published works on this matter shows that ent. The submarine outfall is another important source there are important discrepancies (Domingues et al., of nutrients in this area, probably the main source of 2011). Some authors have reported that N-limitation is DIP, because the sewage plant of Gandia discharges into more probable than P-limitation in areas of the Western the sea through this. The higher values of DIN and DIP Mediterranean (Owens et al., 1989; Denis. Karafistan et observed in summer (fig.4) could be a consequence of the al., 1998; Olivos et al., 2002). However, in coastal areas increase in population, which generates a higher flow of of the Catalan Sea (Olivos et al., 2002) Si acted as the sewage in the submarine outfall. Furthermore, the sewage main limiting nutrient. In our study area, as regards nutri- plant, which is located next to the river, was unable to ent limitations for phytoplankton, phosphorus appeared treat all wastewater received and discharged the excess to be the only potential limiting nutrient in all seasons directly into the Serpis river. Moreover, the rainwater except during the dry winter which favoured potential that was collected by the collector system in the days Si-limitation before autumn monitoring was also brought to the treat- ment plant because wastewater and pluvial water are not Chl-a concentration observed in the study area (0.02- separated and it was discharged into the sea through the 11.71 μg l-1) was similar to that observed by Olivos (2002) submarine outfall. This fact could explain the high levels in the Catalan sea. In the Mediterranean Sea, phytoplank- of silicate in the outfall plume in autumn because anthro- ton biomass, as Chl-a, generally displays low values (less pogenic nutrient enrichment usually increases N and P, than 0.2 μg l−1) over large areas, with a modest late winter but not Si (Domingues et al., 2011). increase (up to 3 μg l−1) (Siokou-Frangou, 2010). In our study, the highest values were observed in winter monitor- Generally, nitrogen is considered limiting in marine ing and minimum values were registered in summer and systems (Ryther and Dunstan, 1971) and phosphorus autumn. A strong Chl-a signal in late winter-spring and in freshwaters (Schindler, 1977), but these two deeply summer-autumn minima have been detected in many areas rooted dogmas have been questioned (Sterner, 2008; of the Mediterranean sea (e.g., Cruzado and Velásquez,

48 Thalassas, 29(1) · January 2013 SEASONAL DYNAMICS OF THE PHYTOPLANKTON COMMUNITY IN THE GANDIA COASTAL AREA, SOUTHERN GULF OF VALENCIA

CCA

2.0 Axis 2 Axis

GDEL

PMIN PLIM

1.0

Temperature Light penetration Radiation PSEU GYM NitritNO2 es SCRI COSC Axis 1 0.0 PTRI EUTR -2.0 PMIC -1.0 0.0 NCL CHDA 1.0 rain HETE Dis. Oxygen SKCO NOSC NitratesNO3 THNI AGLA THAL CHPE

-1.0

Figure 10: Correlations plot of the canonical correspondence analysis (CCA), on the relationship between environmental variables and species which may be nocive (HAB).

1990; Lévy et al., 1998 a,b; Ribera d’Alcalà et al., 2004, and the different chlorophyll content of phytoplankton spe- Siokou-Frangou, 2010).In the Mediterranean, a winter cies. In the Gandia coastal area, the important contribution phytoplankton bloom appears to be quite widespread, due of picoplankton and nanoplankton to phytoplankton bio- to recurrent periods of calm weather in the season, gener- mass during summer and spring was reported by Sebastià ally associated with the expansion of the Siberian high (2012) using diagnostic photopigment analysis. According pressure system towards the West (Duarte et al., 1999; to Sebastià (2012) the contribution of small forms (<20 μm) Ribera d’Alcalà et al., 2004). Indeed, the last winter bloom to total Chl-a could reach 38.9 % in the entrance to Gandia has been defined as the unifying feature for phytoplankton harbour. Similar conditions were observed in the Iskenderun in the Mediterranean Sea (Travers, 1974; Duarte et al., Bay (Northeastern Mediterranean) where the highest values 1999; Ribera d’Alcalà et al., 2004; Siokou-Frangou, 2010). of Chl-a and TP were registered in early March (2.78 μg l−1) but not an increase in the cell abundance (Polat, 2001). In the winter monitoring campaign, the highest values of TP and Chl-a (average value 2.55 μg l−1) were registered The study found a total of 108 phytoplankton spe- and DIP was very scarce (fig. 3 and fig. 4). In the study cies of nine different algal classes (mostly dinoflagellates area, according to Sebastià et al., (2012) higher phosphorus and diatoms). Diatoms were the most dominant group in levels were observed in surface irrigation channels during terms of abundance: toxic Pseudo-nitzschia species were last winter and spring and have been attributed to diffuse among the most abundant and frequent diatom, and this sources, because they coincided with the period of phospho- genus showed the annual diatom trends. This fact was rus fertilizer application. In our study, DIP concentrations observed in the Balearic Archipelago by Puigserver et al., are very low (fig. 4), furthermore it is the main potentially (2010). Other representative species in terms of abundance limiting nutrient, so any phosphorus discharge through the were Bacillaria paxillifera and Asterionellopsis Glaciallis irrigation channels is rapidly consumed and incorporated and, in terms of frequency Cylindrotheca closterium and as biomass (Falco et al., 2010). Thus,the highest values of Chaetoceros affinis. Diatom abundance did not show the Chl-a and TP may indicate a winter-early spring bloom. typical seasonal cycle of maximum abundances in spring Smith (2006) observed a strong correlation between biomass and minimum abundances in summer. Diatoms registered and TP. In our study, despite higher Chl-a and TP values, an the highest values of abundance in autumn (fig. 6) and increase in cell abundance was not observed. This might be the highest relative abundance in summer (fig.5). The key due to the small size fraction of phytoplankton (<20 μm) factor supporting the summer population seems to be the

Thalassas, 29(1) · January 2013 49 I. GADEA, M. RODILLA, J. SOSPEDRA, S. FALCO & T. MORATA

Table 1: Measured physicochemical and community structure parameters and chlorophyll-a means, standard deviations, minimum and maximum values of stations grouped by seasons.

SUMMER AUTUMN WINTER SPRING X į min max X į min max X į min max X į min max Water temperature (ºC) 27.30 0.87 26.20 30.30 20.85 0.48 19.60 22.20 13.16 0.40 12.70 14.10 20.82 0.90 19.60 23.00 Radiation (W m-2) 663 137 378 849 225 95 118 320 642 178 127 686 867 140 577 958 Salinity (g kg-1) 37.37 0.69 34.60 37.80 36.66 1.63 27.80 37.50 37.29 0.33 36.00 37.60 36.75 1.36 30.20 37.80 Dissolved oxygen (mgl-1) 7.00 0.14 6.55 7.14 7.44 0.36 6.82 8.38 9.65 0.22 9.10 9.87 8.76 0.40 7.94 9.30 pH 7.91 0.06 7.72 8.01 8.15 0.04 8.08 8.22 8.14 0.02 8.08 8.17 8.20 0.03 8.12 8.26 Secchi depth (m) 7.58 5.22 0.50 17.00 2.98 1.50 0.50 5.50 5.28 3.04 0.20 10.00 3.19 1.77 0.20 8.00 Suspended solids (mg l-1) 10.42 2.76 7.00 20.43 10.41 1.80 5.50 15.75 16.41 14.61 5.50 63.30 11.34 3.80 6.29 27.67

DIN (μM) 6.95 6.59 2.86 36.52 2.80 3.27 0.80 17.26 2.98 2.51 1.11 14.56 5.79 6.24 1.43 27.42 DIP (μM) 0.16 0.28 0.02 1.06 0.12 0.32 0.01 1.84 0.03 0.03 <0.01 0.15 <0.01 <0.01 <0.01 <0.01 TP (μM) 0.35 0.34 0.09 1.78 0.29 0.29 0.14 1.91 0.39 0.11 0.16 0.68 0.24 0.11 0.06 0.53 DSi (μM) 5.2 2.5 2.3 14.4 3.2 4.8 0.5 28.1 1.0 1.4 0.0 6.2 2.8 2.6 0.4 12.1 DIN:DIP 123.8 119.6 4.0 675.6 42.6 32.1 5.2 129.1 285.7 673.6 13.8 3533.2 236.8 251.8 57.4 1096.8 DSi:DIN 1.0 0.3 0.2 1.4 1.1 0.4 0.3 2.4 0.3 0.2 0.0 0.8 0.5 0.2 0.2 1.5 DSi:DIP 106.8 61.0 4.55 232.0 50.2 45.9 3.8 180.1 75.0 140.8 0.4 695.4 110.6 104.0 17.1 483.2

Diversity (H', bits ind-1) 1.35 0.56 0.02 2.40 1.46 0.37 0.67 2.27 1.58 0.37 1.05 2.40 2.03 0.44 1.03 2.70 Evenness ( J) 0.30 0.12 0.00 0.51 0.32 0.08 0.14 0.49 0.34 0.08 0.23 0.52 0.43 0.09 0.22 0.57 Richness (S) 8.03 4.10 3 17 14.12 4.00 8 25 11.48 2.75 7 18 14.68 4.31 5 21 Total chlorophyll-a (μgl-1) 0.06 0.08 0.02 0.45 0.14 0.06 0.06 0.32 2.55 2.54 0.12 11.71 0.18 0.13 0.02 0.76

continuous availability of silica (even in the dry period) the period of phosphorus fertilizer application in the crops together with the optimal light and temperature conditions. an increase in the dinoflagellate abundance was observed in The lowest density and relative abundance of this group the harbour since it received the discharges from the chan- was reached in spring in spite of the high concentrations nels that drain the wetland. In spring dinoflagellates reached of DSi. In this season dinoflagellates showed the highest their highest abundances and relative abundance (fig.8) in densities. the whole area, but mainly in the harbour. Phytoplankton abundance, including dinoflagellates was triggered by the In ecosystems with phosphorus limiting conditions increase in the incident light, and that increase led to a reduc- and high nitrate and silicate levels, inputs of phosphorus tion of the DIP to levels below the detection limit because could trigger the undesired effects of phytoplankton species of nutrient assimilation. According to Fisher et al. (1999) responsible for the generation of harmful blooms (Sebastiá light can limit or co-limit algal growth in marine environ- et al., 2012). In our study, the highest concentrations of ments that present high nitrogen inputs. This spring increase dinoflagellates were always observed in the areas where the was characterized by a dominance of genera Heterocapsa, lowest DIP concentrations were registered despite the fact Scrippsiella and Gymnodinium. Some species that belong to that at the same time those areas were producing the high- these genera are capable of phagotrophy which is advanta- est nutrient load (fig. 3 and fig.4). This fact shows that any geous in inorganic nutrient-depleted waters (Stoecker et al., phosphorus discharge in this area is rapidly consumed and 2006).The heterotrophic dinoflagellates are important in the incorporated by phytoplankton, including dinoflagellates.In trophic dynamics of the plankton community due to their summer, dinoflagellates appeared mainly in the mouth of various feeding strategies (Jeong, 1994; 1999; Barría and the Serpis river (fig. 8 and fig. 9) when the treatment plant Piccolo, 2008). Dinoflagellates spring bloom was observed capacity is exceeded due to the population increase and the in the coastal waters of the Balearic Archipelago (Puigserver wastewater collector discharges into the Serpis directly. In et al., 2010), Izmik Bay (Aktan et al., 2005) and in the autumn, they appeared in the Ahuir Beach (fig.8 and fig.9) Catalan Sea, where maximum concentrations were detected when groundwater discharges were higher (fig. 2). During during spring and summer (Vila and Masó, 2005).

Table 2:

Percentage when DIN, PO4 or SiO2 act as potential limiting nutrient.

% limiting nutrient % without %DIN %PO4 %SiO2 Summer 6.25 87.50 3.13 3.13 Autumn 0 63.64 3.03 33.33 Winter 0 63.64 33.33 3.03 Spring 0 100 0 0

50 Thalassas, 29(1) · January 2013 SEASONAL DYNAMICS OF THE PHYTOPLANKTON COMMUNITY IN THE GANDIA COASTAL AREA, SOUTHERN GULF OF VALENCIA

Table 3a: Taxa found in the study area. % Np: percentage of total samples where the taxa was recorded; Av>0: averaged density (cells l-1). Abundance total: sum of cell abundance in all samples taken. Number indicates the maximum abundance in each season (cells l-1), n indicates that this species was found in a net sample.

Taxa % Np Av>0 Abundance total SUMMER AUTUMN WINTER SPRING

DINOFLAGELLATES Akashiwo sanguinea Hirasaka 5.6 45 360 40 40 80 Alexandrium sp. 8.4 90 1080 40 40 40 200 Centrodinium maximum Pavillard 1.4 40 80 80 Ceratium candelabrum (Ehrenberg) Stein n Ceratium extensum (Gourret) Cleve n Ceratium euarcuatum E.G.Jørgensen 2.1 40 120 40 Ceratium furca Ehrenberg 18.2 60 1560 40 40 40 160 Ceratium fusus Ehrenberg 9.8 44 620 40 40 40 80 Ceratium longirostrum Gourret 2.8 40 160 40 40 Ceratium karstenii Pavillard (=C. arcuatum (Gourret 1883) Cleve 1900) 0.7 40 40 40 Ceratium macroceros Ehrenber n Ceratium trichoceros Ehrenber n Ceratium tripos Müller 3.5 40 200 40 40 Dinophysis caudata Saville-Kent 0.7 40 40 40 Dinophysis sacculus Stein 0.7 40 40 40 Diplopsalis sp. 4.9 57 400 120 240 Gonyaulax sp. 3.5 56 280 80 Gymnodinium spp. 53.8 174 13380 160 200 240 1200 Gyrodinium sp. 16.8 93 2220 420 80 40 240 Heterocapsa spp. 25.2 584 21040 20 80 40 2120 Heterodinium dispar Kofoid & Adamson n Karenia sp. 2.1 53 160 80 40 Noctilluca scintillans (Macartney) Kofoid & Swezy 10.5 82 1240 40 200 Oxytoxum sp. 1.4 30 60 40 Pentapharsodinium tyrrhenicum (Balech) Montresor, Zingone et Marino 13.3 101 1920 40 280 Peridinium quinquecorne Abé n Podolampas spinifera Okamura 1.4 40 80 40 Polykrikos kofoidii Chatton 0.7 40 40 40 Prorocentrum lima (Ehrenberg,) Stein 6.3 58 520 120 40 80 40 Prorocentrum micans Ehrenberg 21.7 87 2680 40 80 40 240 Prorocentrum minimum (Pavillard) Schiller 7.7 49 540 80 80 40 40 Prorocentrum triestinum Schiller 9.1 81 1060 20 40 280 Prorocentrum sp. 2.1 53 160 120 Protoperidinium claudicans (Paulsen ) Balech 1.4 40 80 40 40 Protoperidinium crassipes (Kofoid) Balech 7 44 440 40 80 Protoperidinium diabolus(Cleve) Balech 22.4 180 5760 80 560 Protoperidinium divergens (Ehrenberg) Balech 2.8 40 160 40 40 Protoperidinium leonis (Pavillard) Balech n Protoperidinium murrayi (Kofoid) Hernández-Becerril 0.7 40 40 40 Protoperidinium punctulatum (Paulsen ) Balec 1.4 40 80 40 Protoperidinium pyriforme (Paulsen) Balech 9.1 82 680 40 40 160 Protoperidinium sphaericum (Murray & Whitting) Balech 4.9 51 360 40 80 Protoperidinium steinii (Jørgensen ) Balec 0.7 20 20 20 Protoperidinium sp. 4.9 43 300 20 40 40 80 Pyrocystis elegans Pavillard 0.7 40 40 40 Pyrophacus sp. 0.7 40 40 40 Scrippsiella spp. 44.1 218 13760 160 200 1120 1960 Spiraulax jollifei (Murray & Whitting) Kofoid 1.4 40 80 80 Dynophyceae spp. 16.1 78 1800 680 120 80 80

Ongun, 2007, Sebastiá et al., 2012). On the other hand, Euglenophytes appeared mostly in the rainy seasons different chlorophytes are characteristic of brackish and and chlorophytes appeared in spring (fig. 6).In general, polluted waters, and their distribution has been associ- higher densities of both groups were observed at the ated to freshwater plume (Soler et al., 1995). Moreover, mouth of the Serpisat Venecia Beach and in the entrance according to Ramirez et al., (2005) high DIN:DIP molar of the Gandia harbour. Venecia beach is a semi-enclosed ratios enhance the development of chlorophytes. These bay where the Serpis river and the wastewater treatment conditions exist at Venecia Beach. plant collector outflow. Furthermore, the breakwater of the harbour reduce the impact of northeast currents, Phytoplankton community structure analyses based which are predominant in the area in autumn, winter and on the similarity of phytoplankton abundance among sta- spring (CEDEX, 1997), this causes a reduction in hydro- tion groups showed a clear difference between stations dynamics and an increase in the water residence time. located near the shoreline and the more distant stations. Euglenophytes have been observed in other euthrophic Furthermore, species richness is the simplest way to systems where they have been related to high nutrient lev- describe community diversity, and diversity indices have els and decreasing turbulence (Olly et al, 1996; Celik and been used to determine spatial and temporal variations

Thalassas, 29(1) · January 2013 51 I. GADEA, M. RODILLA, J. SOSPEDRA, S. FALCO & T. MORATA

Table 3b: Taxa found in the study area. % Np: percentage of total samples where the taxa appeared; Av>0: averaged concentration (cells l-1). Abundance total: sum of cell abundancein all samples taken. Number indicates the maximum abundance in each season (cells l-1), n indicates that this species was found in a net sample.

Taxa % Np Av>0 Abundance total SUMMER AUTUMN WINTER SPRING DIATOMS Achnanthes sp. 21 59 1780 80 120 120 120 Amphora spp. 4.9 40 280 40 40 Astartiella sp. 4.8 40 280 200 40 Asterionellopsis glacialis(Castracane) Round 29.4 5584 234560 40 21640 10200 4600 Asteromphalus spp. n Bacillaria paxillifera (Müller) Hendey 82.5 4722 557220 491580 800 2840 23360 Bacteriastrum sp. 1.4 120 240 200 Bleakeleya sp. 4.9 43 300 20 80 40 Cerataulina pelagica (Cleve) Hendey n Chaetoceros affinis Lauder 49.7 1125 79920 640 3840 7000 320 Chaetoceros atlanticus (Schütt) Hustedt n Chaetoceros concavicorne Mangin 0.7 40 40 40 Chaetoceros danicus Cleve 7 56 560 120 80 Chaetoceros simplex Ostenfeld 0.7 20 20 20 Chaetoceros socialis Lauder n Chaetoceros peruvianus Brightwell 7 56 560 80 40 Coscinodiscus centralis Ehrenberg 28 60 2400 40 120 200 120 Cylindroteca closterium (Ehrenberg) Reimann & Lewin 51 114 8340 40 520 560 280 Diploneis sp. 10.5 71 1060 40 280 200 40 Eucampia sp. 2.1 133 400 120 240 Fragilariopsis spp. 0.7 80 80 80 Gossleriella tropica Schütt 1.4 40 80 40 40 Guinardia delicatula (Cleve) Hasle 28.7 664 27260 8920 440 680 200 Helicotheca tamesis (Shrubsole) Ricard n Hemidiscus sp. 0.7 40 40 40 Lauderia annulata Cleve 3.5 28 140 40 40 Leptocylindrus mediterraneus (H. Peragallo) Hasle 22.4 198 6340 280 760 800 240 Licmophora spp. 7.7 554 6100 40 5720 80 Melosira spp. 7.0 556 5560 1600 1120 80 Navícula spp. 28.0 53 2120 140 40 80 80 Nitzchia longissima (Brébisson in Kützing) 5.6 260 2080 1680 40 120 Odontella mobiliensis (Bailey) Grunow 12.6 139 2500 760 200 760 120 Planktoniella sp. 0.7 20 20 20 Pleurosigma sp. 17.5 60 1500 160 120 40 200 Proboscia alata (Brightwell) Sundström 72 167 17240 540 680 800 400 Pseudo nitzschia spp. 55.9 6754 540330 408510 19360 3800 200 Rhizosolenia spp. 18.9 132 3560 480 40 80 Skeletonema costatum (Greville) Cleve 23.8 865 29440 800 2120 2920 2120 Striatella unipunctata (Lyngbye) Agardh 0.7 3760 3760 3760 Thalassionema nitschioides (Grunow) Merschkowsky 43.4 895 55460 80 4640 480 360 Thalassiosira spp.Grunow 8.4 403 4840 1960 560 40 Thalassiotrix spp. 0.7 40 40 40 EUGLENOPHYTES Eutreptiella gimnastica Throndsen 17.5 86 2140 40 160 480 80 Eutreptia spp. 49.7 115 8160 200 440 240 280 CHLOROPHYTES Scenedesmus spp. 1.4 200 400 160 240 Sphaerocistis spp. 1.4 100 200 120 80 Chlorophycea spp. 18.2 138 3600 40 80 200 920 RAPHYDOPHYTES Chatonella subsalsa B.Biecheler 0.7 40 40 40 Chatonella sp. 52.4 405 30400 200 4240 1840 120 HAPTOPHYTES Phaeocystis spp. Lagerheim 1.4 40 40 40 40 Phaeocystis cordata Zingone & Chrétiennot-Dinet n Phaeocystis globosa Scherffel n CHRYSOPHYTES Bicosoeca spp. 2.8 60 240 80 40 40 Dinobryon sp. 4.9 57 400 40 120 Dinobryon balticum (Schütt) Lemmermann 0.7 40 40 40 DICTIOPHYTES Ciliophrys infusionum Cienkowski 0.7 40 40 40 Dictyocha staurodon Ehrenberg 0.7 40 40 40 Octactis octonaria (Ehrenberg) Hovasse 4.9 120 840 320 CRYPTOPHYTES Telonema subtile Greissmann n

induced by natural and anthropogenic disturbances (He and the case of species number, the highest values were regis- Legendre, 2002; Gonídez-Dominguez et al., 2009; Aktan, tered in autumn and spring. Coastal waters influenced by et al 2011). Spring monitoring presented significantly continental runoff (natural or anthropogenic) show higher higher (p<0.05) values of diversity and evenness and, in concentrations of Chl-a than their surrounding waters as

52 Thalassas, 29(1) · January 2013 SEASONAL DYNAMICS OF THE PHYTOPLANKTON COMMUNITY IN THE GANDIA COASTAL AREA, SOUTHERN GULF OF VALENCIA

a result of this fertilization (Magazzu and Decembrini, most abundant genera, the highest concentrations of these 1995; Agawin et al., 1998; Duarte et al., 2000; Olivos species (2 x 106 cells l-1) were observed inside the harbour et al., 2002). This fact has been observed in the coastal and were similar to those observed in the harbours of area of Gandia near the discharge of the Serpis river and Catalonia (Vila and Masó, 2005). Among harmful diatoms, channels that drain the Safor Wetland. However, in our the genus Pseudo-nitzschia showed a positive correlation study a discrepancy was observed between high nutrient with high nitrate and nitrite concentration and a nega- concentration and low biological response in the subma- tive correlation with precipitations and dissolved oxygen rine outfall plume, as had been previously observed in (fig. 10). This genus reached its highest concentration in studies of the effects of sewage discharge through outfalls summer (408 x 103 cells l-1) at the harbour entrance. The in Hawaiian coastal waters (Ed Parnell, 2003) and in the southeast currents created by wind action are prevalent Northern Adriatic Sea (Mozetič et al., 2008). According dominant on the Gandia coast in summer (CEDEX, 1997). to Demir and Kirkagac (2005) and Mozetič et al., (2008) This causes marine water to enter into the harbour and in the case of short water retention time phytoplankton produces a turbulent environment in the harbour entrance growth is not sustained in spite of high levels of nutrients. due to the orientation of its entrance channel. Furthermore, The majority of the phosphorus observed in the outfall DIN (mainly nitrates) and DSi values were significantly plume was inorganic, especially at high concentrations of higher (fig. 3) than other areas and they were the maximum TP. According to Mozetič et al., (2008) due to P-depleted values reached in the harbour during the study period. organic substrate, bacteria might have prevailed over phy- These high levels could be the consequence of wastewater toplankton for phosphate. discharges near the mouth of the Serpis river and the water pumped for summer irrigation that outflows through the During the study period, thirty-one toxic and harm- channels into the harbour. Diatoms tend to dominate in ful species were recorded (table 5). Among them, twelve high-nutrient and turbulence environments (Song et al., species are included in the IOC list 2009 (Moestrup et 2009), these conditions may favour diatom bloom, specifi- al., 2009), mainly dinoflagellates. Higher cell abundance cally, the growth of Pseudo-nitzschia species (Puigserver and recurrence of dinoflagellates were observed in spring et al., 2010). This genera has been observed in Valencia whereas harmful diatoms registered highest abundance and harbour by Assadi et al., (2007) in summer and in dif- occurrence in autumn and winter. The CCA analysis (fig. ferent harbours of northwestern Mediterranean Sea (Vila 10) showed that diatoms were favoured by high nitrate and Masó, 2005). The genera Chatonella only appeared at concentration and low temperatures. On the other hand, Venecia Beach and in the plume of the submarine outfall. harmful dinoflagellates abundance was higher at high This genera has been observed in the Mediterranean Sea in radiation and they were favoured by precipitation events eutrophic coastal areas and brackish coastal areas rich in before monitoring. The highest abundances of harmful organic material (Tomas, 1997; Hallegraeff et al., 2003). diatoms and dinoflagellates were observed in Gandia The euglenophyte Eutreptiella gymnastica only appeared harbour and Venecia Beach (table 4). According to Vila et at Venecia Beach and in Gandia harbour, it has been al. (2001) the interaction between high nutrient levels and described by Olly et al. (1996) as a bloom species adapted confinement plays the key role in the occurrence of dino- to decaying turbulence and high nutrient environments. flagellates in this region. Semi-enclosed gulfs and bays, such as the Venecia Beach, near important harbours and CONCLUSIONS big cities are at higher risk of suffering HABs (EEA 1999, Vila et al., 2001). The mainly harmful dinoflagellates The coastal phytoplankton of Gandia (Gulf of Valencia) observed in the study area were of the genera Alexandrium in the surface layers differs in composition and abundance and Dinophysis, but they did not reach high densities. The in response to the interaction of regional conditions and the genus Gymnodinium proliferates in this area and was the variability imposed by seasonal changes in radiation and most frequent dinoflagellate. According to Soler et al., precipitation, as well as local conditions such as coastal (1995), blooms of this red tide species seem to be related dynamics and nutrient inputs mainly by the river Serpis to continental discharges (low salinities and micro- and and channels that drain the Safor Wetland. On the other macronutrient inputs) and this species blooms in confined hand, the discharge of the effluent from sewage treatment and non confined near-shore waters (Vila et al., 2001). This plant through the submarine outfall does not appear to group reached 1200 cells l-1 in spring, which is much lower significantly impact the phytoplankton community. During than the values recorded in the harbours of the Catalan the study period, from summer 2010 to spring 2011, the Sea (Vila and Masó, 2005),in Valencia (Soler, et al., 1995) phytoplankton succession showed a clear transition from a and in the Alboran Sea (Mercado et al., 2005). The bloom diatom to a non-diatom based assemblage. A relationship forming Heterocapsa spp and Scrippsiella spp were the between phytoplankton succession, nutrient concentration

Thalassas, 29(1) · January 2013 53 I. GADEA, M. RODILLA, J. SOSPEDRA, S. FALCO & T. MORATA

1 3.0 40 40 5 15.2 56 80 1 3.0 40 40 ) -1-1 ). -1 2 6.5 60 80 1 3.0 40 40 O), diatoms (DIAT) and raphidophytes (RAPH), flagellates (FL) haptophytes (HAPT). O), diatoms (DIAT) of occurrences in the season; % Np: percentage of total; Av>0: averaged concentration Av>0: of total; in the season; % Np: percentage of occurrences AUTUMN WINTER SPRING Paralytic shellfish poisoning (PSP), Diarrhetic shellfish posisoning (DSP), Amnesic shellfish shellfish posisoning (DSP), Paralytic shellfish poisoning (PSP), Diarrhetic Table 5: Table Table 4: Table SUMMER ), calculated from frequency which cells were detected; Max.: Maximum cell concentration (cells l which cells were frequency ), calculated from -1 Indicator species of anthropogenic pressure in the study area. Av>0: averaged density (cells l Av>0: in the study area. pressure Indicator species of anthropogenic (cells l 00000 0040 00 0040 0040 0 40 0 200 40 203 760 0 0 200180880 496 210 326 260 0 340 1413 0 106 0 0 160 46861270 1187 180 310 520 240 600 480 0 71491 4305 9760 1720 520 HARBOUR ENTRANCE BEACH MOUTH RIVER/VENECIA OF SERPIS MOUTH BEACHVACA/AHUIR OF WATERCOURSE SUBMARINE OUTFALL (F1) STATION CONTROL CCL DIAT i bf 1 0.2 40 40 25 75.8 120 520 25 80.6 125 560 13 39.4 55 280 KAR DINO i NSP GON DINO i NTX AMP DIAT i ASP 2 6.1 40 40 5 15.2 40 40 PTRI DINO i bf 1 0.2 20 20 1 3.0 40 40 11 33.3 91 280 SCRI DINO i bf 6 1.0 67 160 11 33.3 87 200 15 48.4 171 1120 31 93.9 337 1960 GYM DINO i/c bf* 13 40.6 68 160 10 30.3 68 200 20 60.6 78 240 33 100.0 333 1200 THNI DIAT c bf 1 0.2 80 80 33 100.0 1510 4640 19 57.6 243 480 8 24.2 160 360 PLIM DINO i DSP 2 0.3 100 120 2 6.1 40 40 3 9.7 40 80 2 6.1 40 40 CPEL DIATPSEU DIAT c i bf ASP* 13 40.6 37351 408510 33 100.0 2223 19360 29 90.6 731 3800 2 6.1 120 200 PMIC DINO i bf 1 0.2 40 40 5 15.2 48 80 2 6.5 40 40 24 72.7 104 240 CFUS DINO i Fish-killing 2 0.3 30 40 1 3.0 40 40 3 9.7 40 40 7 21.2 46 80 PMIN DINO i NTX, bf 3 0.5 60 80 2 6.1 60 80 1 3.2 40 40 4 12.1 40 40 CHPE DIAT i bf 9 27.3 58 80 1 3.1 40 40 HETE DINO i bf* 1 0.2 20 20 2 6.1 60 80 2 6.5 40 40 31 93.9 693 2120 COSC DIAT iEUTR FL bf 4 i 0.7 bf 30 2 40 0.3 14 30 42.4 40 69 5 120 15.2 11 96 35.5 160 65 8 200 25.8 10 135 30.3 480 64 10 120 30.3 52 80 DSAC DINO i DSP ALEX DINO i PSP, bf 1 0.2 40 40 2 6.1 40 40 1 3.2 40 40 8 24.2 115 200 GDEL DIATSKCO DIATTHAL DIAT cCHSU RAPHPHAC c HAPT bf c i bf i 19 bf Fish-killing Fish-killing 3 59.4 1 1 0.5 1214 0.2 0.2 393 8920 40 40 800 9 40 40 21 27.3 63.6 156 7 851 440 21.2 2120 11 526 9 34.4 1960 28.1 185 4 1005 680 1 12.5 2920 4 3.2 307 1 12.1 40 560 3.0 100 40 1 2120 200 3.0 2120 40 40 NOSC DINO i bf 5 15.2 40 40 10 0.3 120 200 AGLA DIAT c bf* 1 0.2 40 40 29 87.9 6421 21640 7 20.0 1128 10200 1 3.0 4600 4600 CHCO DIAT c Fish-killing 1 3.0 40 40 DCAU DINO i DSP CHDA DIAT c bf 5 15.2 70 120 5 15.6 50 80 AKSAN DINO i bf 1 0.2 40 40 1 3.2 40 40 5 15.2 48 80 Pseudo-nitzschia spp. Pseudo-nitzschia Guinardia delicatula Guinardia Nitzschia longissima Noctiluca scintillans Octactis octonaria mobiliensis Odontella sp. Scrippsiella Taxa sp. Chatonella gimnastica Eutreptiella tropica Gosleriella costatum Skeletonema Av>0 Av>0 Av>0 Av>0 Av>0 lis(Castracane) Round lis(Castracane) Cell type refers to individual cells (i), chain forming o colonial cells (c); Harmful refers to the potencially harmful effect: to individual cells (i), chain forming o colonial (c); Harmful refers Cell type refers poisoning (ASP), Neurotoxic (NTX), fish-killing and bloom forming (bf), an asterisk * indicates high concentrations. Np: number poisoning (ASP), Neurotoxic Main characteristics of harmful taxa. Code: abbreviation used in CCA.Taxonomic group (Tax group) refers to dinoflagellates (DIN refers group) (Tax group used in CCA.Taxonomic Main characteristics of harmful taxa. Code: abbreviation Gonyaulax sp. Dinophysis caudataDinophysis Saville-Kent glacia Asterionellopsis Mangin concavicorne Chaetoceros Cleve danicus Chaetoceros Brightwell peruvianus Chaetoceros Ehrenberg centralis Coscinodiscus Hendey Cerataulina pelagica (Cleve) J.C.Lewin CylindrothecaReimann closterium & Hasle Guinardia delicatula (Cleve) Pseudonitzschia spp. Cleve Skeletonema costatum(Greville) Mereschkowsky Thalassionema (Grunow) nitzxchioides spp.Grunow Thalassiosira Throndsen gimnastica Eutreptiella Chatonella subsalsa B. Biecheler spp. Lagerheim Phaeocystis Ceratium fusus Ehrenberg Amphora spp. Taxa sanguineaAkashiwo Hirasaka Alexandrium sp. spp. Scrippsiella Code Group Tax Type Cell Harmful Np %Np Av. (>0) Max. Np %Np Av. (>0) Max. Np %Np Av. (>0) Max. Np %Np Av. (>0) Max. Noctilluca scintillans (Macartney) Kofoid & Swezy Noctilluca scintillans (Macartney) Kofoid & Schiller triestinum Prorocentrum Prorocentrum lima (Ehrenberg,) lima (Ehrenberg,) Stein Prorocentrum Ehrenberg micans Prorocentrum Schiller minimum (Pavillard) Prorocentrum Heterocapsa spp. Heterocapsa et Moestrup spp.Karenia Hansen Gymnodinium spp. Dinophysis sacculus Stein

54 Thalassas, 29(1) · January 2013 SEASONAL DYNAMICS OF THE PHYTOPLANKTON COMMUNITY IN THE GANDIA COASTAL AREA, SOUTHERN GULF OF VALENCIA

Table 6: Rank Spearman’s correlation matrix between phytoplankton groups and environmental variables.

and nutrient ratios seemed to exist. In the dry winter, high (2003). Manual on harmful marine microalgae. Monographs values of TP and Chl-a could indicate a last winter bloom. on Oceanographic Methodology, 11. UNESCO Publishing, In spring, a dinoflagellate bloom was observed when there Paris, France, 793. was high radiation, very low DIP, high DIN:DIP and low Anderson DM(2009). Approaches to monitoring, control and man- DSi:DIN molar ratios, during the period of phosphorus agement of harmful algal blooms (HAB’s), Ocean and Coastal fertilizer application in the crops of the Safor Wetland.The Management, 52:342-347. inputs of phosphorus from agriculture seem to have a sig- APHA (2005). Standard methods for the examination of water nificant response in the phytoplankton community.Gandia wastewater, 21th edition,American Public Health Association, Harbour and Venecia Beach are areas with high risk of American Water Works Association, Water Environment suffering HABs, as a consequence of the continous nutrient Federation, Washington. inputs from agriculture and wastewater discharges and the Assadi C, Tasso V, García A.M (2007). Progress and trends in reduced water exchange (high water residence time). phytoplankton and biotoxins: In Javier Gilabert, Universidad Politécnica de Cartagena: Actas de la IX Reunión Ibérica ACKNOWLEDGEMENTS sobre Fitoplancton Tóxico y Biotoxinas, Cartagena, 2008, 87-92. Financial support for this research was provided by Ballesteros-Navarro BJ (2003). Estado y evolución de los procesos Ministry of Education, Culture and Sport, Government de intrusión marina en la unidad hidrogeológica 08.38. Plana of Spain, through the Training Program for University de Gandia-Denia (Valencia-Alicante, España), In: Lopez Teachers (FPU). We would like to express our deepest Geta JA, de la Orden JA, Gómez JD, Ramos G, Mejías M, thanks to Margarita Fernández and Vanessa Castan of IRTA Rodríguez L, Ed., Tecnología de la intrusión de agua de mar (Research Institute of Technology, food and Agriculture). en acuíferos costeros: países mediterráneos. IGME, Madrid, p. 585-595. REFERENCES Barría MS,Piccolo MC (2008). Presencia y variación estacional del dinoflagelado heterótrofo gyrodinium fusus (meunier) Agawin NS, Duarte CM, Agustí S(1998). Growth and abundance akselman en el estuario de Bahia Blanca, Argentina ,Atlantica, of Synechococcus sp. in a Mediterranean Bay: Seasonality Rio Grande, 30(136 2) 129-137. and relationships with temperature, Marine Ecology Progress Beman J, Arrigo K, Matson P(2005). Agricultural runoff fuels Series, 170: 45-53 large phytoplankton blooms in vulnerable areas of the ocean, Aktan Y, Tüfekçi V, Tüfekçi H, Aykulu G (2005). Distribution Nature, 434: 211-214. patterns, biomass estimates and diversity of phytoplankton Brito A, Newton A, Tett P, Fernandes T (2010) Sediment- in Izmit Bay (Turkey), Estuarine, Coastal and Shelf Science, water interactions in a coastal shallow lagoon, Ria Formosa 64(2-3): 372-384. (Portugal): Implications within the Water Framewor Directive, Aktan Y (2011). Large-scale patterns in summer surface water phyto- Journal of Environmental Monitoring, 12: 318-328. plankton (except picophytoplankton) in the Eastern Mediterranean. Caroppo C(2000). The contribution of picophytoplankton to com- Estuarine, Coastal and Shelf Science, 91:551-558. munity structure in a Mediterranean brackish environment, Aminot A, Chaussepied M (1983). Manuel des analyses chimiques Journal of Plankton Research, 22: 381-397. en milieu marin, Centre National pour l’Explotation des Caroppo C, Turicchia S, Margheri MC(2006). Phytoplankton Oceans, Brest, 396. assemblages in coastal waters of the northern Ionian Sea Andersen P, Throndsen J (2003). Estimating cell numbers, in: (eastern Mediterranean), with special reference to cyano- Hallegraeff, G.M.; Anderson, D.M.; Cembella, A.D. (Ed.) bacteria, Journal of the Marine Biological Association of the

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(Received: June 6, 2012; Accepted: November, 7, 2012)

58 Thalassas, 29(1) · January 2013 Thalassas, 29(1) · January 2013: 59-75 An International Journal of Marine Sciences

SEASLUGS (Mollusca: Opisthobranchia) FROM CAMPECHE BANK, YUCATAN PENINSULA, MEXICO

DENEB ORTIGOSA(1,*), NUNO SIMÕES(1) & GONÇALO CALADO(2)

(1) UMDI-Sisal, Facultad de Ciencias, Universidad Nacional Autónoma de México. Apartado postal 70-153, C.P. 04510, Mexico, D.F. (2) Universidade Lusófona de Humanidades e Tecnologias, Av. do Campo Grande, 376 1749-024, Lisboa, Portugal. * [email protected], [email protected], [email protected]

ABSTRACT

Little is known about the seaslugs in the Mexican coast of the Gulf of Mexico and almost all the species reported are either large or have a well-developed calcareous shell. Through specific sampling methods focused in opisthobranchs fauna, in two lagoons and three coral reefs of the Campeche Bank, Yucatan Peninsula, we have recorded 51 species belonging to the clades Cephalaspidea, Aplysiomorpha, Sacoglossa, Eutenidiacea, and Cladobranchia. Of these, 30 species had not been previously reported for the Campeche Bank and 20 out of those are new records for the Atlantic coast of Mexico. The nudibranch Tambja cf. tenuilineata could be the first record for the east coast of the Atlantic Ocean. With this study, the actual number of opistho- branch fauna in the Campeche Bank are 84 species.

Key words: Opisthobranchs, Mexico, Biodiversity, Biogeography, Mollusks, Campeche bank, Yucatan.

RESUMEN (Opistobranquios del banco de Campeche, Península de Yucatán, México)

Se sabe poco sobre los opistobranquios de la costa mexicana del Golfo de México y la mayoría de las especies reportadas son especies con conchas grandes o bien desarrolladas. A través de muestreos dirigidos específicamente a la fauna de opisto- branquios realizados en dos lagunas y en tres arrecifes del Banco de Campeche, península de Yucatán, se reportan 51 especies pertenecientes a los Clados Cephalaspidea, Aplysiomorpha, Sacoglossa, Eutenidiacea y Cladobranchia. De estos, 30 especies son nuevos registros para el Banco de Campeche y 20 de ellos son nuevos registros para la costa Atlántica de México. El nudibranquio Tambja cf. tenuilineata podría ser el primer registro de esta especie para la costa Este del océano Atlántico. Con las aportaciones del presente trabajo, se acumula un total de 84 especies de opistobranquios en el Banco de Campeche.

Palabras clave: Opistobranquios, México, Biodiversidad, Biogeografía, Moluscos, Banco de Campeche, Yucatán.

Thalassas, 29(1) · January 2013 59 DENEB ORTIGOSA, NUNO SIMÕES & GONÇALO CALADO

Figure 1: Sampling sites are indicated with black dots.

INTRODUCTION as Arcas, Triangulos and Arenas Cays, and the large Alacran reef National Marine Park (Spalding, 2004). This There are between 5,000 to 6,000 described bank lies reasonably close to the Caribbean Sea and within opisthobranch species (Wägele and Klussmann-Kolb, the influence of the Yucatan Stream (Chávez and Hidalgo, 2005). From the over 6,000 described opisthobranch 1998; Sheinbaum et al., 2002; Abascal et al., 2003), so species, The Atlantic coast of Mexico has, so far, 111 it should share many species with the Caribbean fauna. species of benthic opisthobranch reported (based on By 2001, only 17 species of opisthobranchs (almost all of Rosenberg et al., 2007 and complete with references them with a conspicuous shell) were reported at different in table 1). However, the opisthobranch records from parts of the Campeche Bank (Rice and Kornicker, 1962, Mexico are scarce and confined to malacological or 1965; García-Cubas et al., 1999; Hicks et al., 2001). Thirty generalist faunistic studies where the opisthobranchs do two species were recently added to the Campeche Bank not represent more than 2% of the taxonomical records inventory (Sanvicente-Añorve et al. 2012), summing up (Zamora-Silva and Naranjo-García, 2008). This is due to to 51 species known. In this work we report the results of an insignificant sampling effort focused exclusively on the first campaigns devoted to the opisthobranch fauna of the opisthobranch fauna of the Atlantic coast of Mexico. three coral reefs of the Campeche Bank and two lagoons To date, there are two studies exclusively dealing with the of Yucatan coast. opisthobranchs fauna, one in five reefs of Veracruz, in the central western part of the Atlantic coast of Mexico MATERIAL AND METHODS (Zamora-Silva and Ortigosa, 2012), and a recent report at the Alacran reef, in the Campeche Bank (Sanvicente- All specimens were collected in five localities Añorve et al., 2012). between October 2006 and May 2008 (table 2, fig. 1). Surveys in the reefs were made using SCUBA equipment The Campeche Bank is a large area situated southwest down to a depth of 20 m and shallow-water surveys of the Gulf of Mexico and northwest of the Yucatan were made with a snorkel or by foot. In both habitats, Peninsula formed by dozens of small reefs rising from the sampling effort was focused on different kinds of depths of 40-60 meters and some submerged banks such substrata such as sand, mud, rocky walls and on diverse

60 Thalassas, 29(1) · January 2013 SEASLUGS (Mollusca: Opisthobranchia) FROM CAMPECHE BANK, YUCATAN PENINSULA, MEXICO

slopes that are normally colonized by benthic organism in Sisal, and four in Serpiente). A total of 51 species of where opisthobrachs are likely to be found such as opisthobranchs belonging to the Clades Cephalaspidea sponges, hydrozoans, bryozoans, tunicates, algae, and (10 species), Aplysiomorpha (6 species), Sacoglossa (13 turtle seagrass meadows (p.e. Thalassia testudinum). The species), Eutenidiacea (13 species), and Cladobranchia (9 undersides of regular-size boulders were also inspected, species) were observed. The most abundant families were taking care to return all rocks to their original position Chromodorididae and Plakobranchidae with eight species (Nybakken, 1974). Collecting methods involved direct each one, and Aplysiidae with six species. Of these, 30 manual capture as well as indirect methods, such as the species are new records for the Campeche Bank, and 20 collection of substrate samples and by brushing part of are new records for the Atlantic coast of Mexico. Thirty the surface into a 1 mm mesh bag. Material collected by six species were sampled in only one site, 23 in the reefs indirect methods was divided into several white trays and 13 in the lagoons (table 2). Eighteen species were containing salt water and left untouched until the decrease collected in the lagoons and 35 species were found in in the oxygen concentration forced the specimens to crawl the reefs. Three species were also found in lagoons with up to the surface looking for areas richer in oxygen. All similar environmental conditions (Bulla occidentalis, specimens were measured and described in vivo under Aplysia brasiliana and Spurilla neapolitana). Only two a stereomicroscope. At least one specimen per species species were present at the three reefs (Elysia patina and was photographed. Afterwards, specimens were put in Hypselodoris picta), and only five species (Chelidonura the refrigerator or anesthetized with magnesium chloride berolina, C. hirundinina, C. cubana, Costasiella or clove oil, and then preserved in 96% absolute ethanol. ocellifera and Chromodoris clenchi) were distributed Some specimens were deposited at the Colección Nacional in the reefs of Sisal and Madagascar. Madagascar and de Moluscos (CNMO) of the Instituto de Biología, Serpiente reefs share three species (Hypselorodis acriba, UNAM. The phylogenetic classification follows Bouchet Mexichromis kempfi and Tambja cf. tenuilineata). Only and Rocroi (2005) down to family level, with the exception Aplysia dactylomela and Dendrodoris krebsii were found of the family Chromodorididae, where we used Johnson at least in one reef and one lagoon. Since diagnosis was and Gosliner (2012); Gosliner et al. (2008) for genera, based on external characters and the geographical range and species are listed in chronological order by year of reported in the literature, we preferred to keep Tambja the description. Data for each species include: Scientific cf. tenuilineata as uncertain species. Finally, external name; Examined material (Sisal (Sis); Madagascar (Mad); characteristics of eight species (Haminoea sp, Ercolania Serpiente (Ser); Yucalpeten (Ycl); La Bocana (Boc)); sp, Chromodoris sp, Doto sp, Okenia sp, Flabellina sp, Date of sampling; Lenght in milimeters (maxim lenght Aeolidiella sp 1, and Aeolidiella sp 2) were insufficient as ML, and L for length of only one specimen); Type of to identify the specimens down to the species level and substrate; Diagnosis (for identification to species level might be undescribed species (for seven of them we only is indicated the publication and the pages that were have one specimen of each). To our best knowledge, this used to identify the specimen; for unidentified species is the first time that images of specimens with these there is a brief description of the main features of the characteristics are shown. A color photograph for these sampled material); Distribution (distribution information unidentifiable species is included (fig. 2). The species was taken from published records: localities of the west recorded through this study are presented in the following coast of the Atlantic ocean are listed in geographical order list: from north to south, west to east, and by country, first the continental countries and then the islands; for Mexico, we Clade Cephalaspidea specified the states of the Atlantic coast of the country Family Bullidae Gray, 1827 where each species record was found, also north to south Bulla occidentalis Adams, 1850 order, following the author of the work. Abbreviations Examined material: Boc: 25 specimens (10-06), ML used for each state were: Tamaulipas, TAMS; Veracruz, 35 mm, on mud and over sea grass; 5 specimens VER; Tabasco, TAB; Campeche, CAMP; Yucatan, (17-05-07), ML 30 mm, over mud and over sea grass YUC; Quintana Roo, QROO. For species with wide (CNMO3015); 1,489 specimens (07-04-08), ML 15 mm, geographical range, the distribution is not specified down over mud; 225 specimens (09-04-08), ML 15 mm, over country level. mud; Ycl: 35 specimens (06-05-08), ML 40 mm, over mud; 200 specimens (07-05-08), ML 40 mm, over sea RESULTS grass (CNMO3040). Diagnosis: Malaquias and Reid, 2007 From the total of 58 samples, 18 were collected in Distribution: USA (North Carolina, Florida, Louisiana lagoons (nine in the Bocana, eight in Yucalpeten, and and Texas); Mexico: VER (Wiley et al., 1982; García- one in Celestun) and 40 in reefs (25 in Madagascar, 11 Cubas and Reguero, 1995; Pérez-Rodríguez, 1997;

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Figure 2: Unidentified species. A. Haminoea sp; B. Okenia sp; C. Ercolania sp; D. Chromodoris sp; E. Flabellina sp; F. Aeolidiella sp 1; G. Aeolidiella sp 2; H. Doto sp.

Zamora-Silva and Ortigosa, 2012), TAB (García-Cubas González-Gándara, 2006; Zamora-Silva and Ortigosa, and Reguero, 1990), YUC (Sanvicente-Añorve et al., 2012), YUC (Vokes and Vokes, 1983; Sanvicente- 2012), QROO (Á. Valdés, personal communication); Añorve et al., 2012), QROO (Ekdale, 1974); Belize; Belize; Honduras; Costa Rica; Panama; Colombia; Honduras; Costa Rica; Colombia; Venezuela; Brazil; Venezuela; Brazil; Uruguay; Bermuda; Curaçao; Bermuda; Cuba; Jamaica; Puerto Rico; Virgin Islands; Cuba; Jamaica; Puerto Rico; Virgin Islands; Bahamas; Martinique; St. Lucia; St. Vincent and the Grenadines; Guadeloupe; Martinique; Dominique; San Martin; Curaçao; Bonaire; Granada; Trinidad and Tobago St. Vincent and the Grenadines; Granada; Barbuda; (Valdés et al., 2006). Antigua; St. Lucia; Guadeloupe; Barbados (Valdés et al., 2006; Malaquias and Reid, 2007). Haminoea antillarum (d’Orbigny, 1841) Remarks: The work of Malaquias and Reid (2007) Examined material: Boc: 183 specimens (30-01-07), proved that the species named as Bulla striata ML 20 mm, over mud; 17 specimens (01-02-07), ML Bruguière, 1792 in the Atlantic coast of Mexico should 6-20 mm, over tree leaves we observed kidney shaped be named as B. occidentalis. Due to this, most of the capsule eggs; 71 specimens (16-02-07), ML 20 mm, species were misidentified as B. striata. over mud; 45 specimens (17-05-07), ML 12 mm, over mud; 304 specimens (07-04-08), ML 15 mm, over mud Family Haminoeidae Pilsbry, 1895 (CNMO3044); 212 specimens (09-04-08), ML 16 mm, Haminoea elegans (Gray, 1825) over mud. Examined material: Boc: 2 specimens 16-02-07, ML Diagnosis: Valdés et al., 2006: 24 14 mm (CNMO3006); 19 specimens (17-05-07), ML Distribution: USA (Florida and Texas); Mexico: VER 17 mm (CNMO2997); 8 specimens (07-04-08), ML 20 (Moore, 1958; García-Cubas, 1971; Vicencio-de la mm; 1 specimen (09-04-08), L 22 mm. All over mud. Cruz and González-Gándara, 2006; Zamora-Silva Diagnosis: Valdés et al., 2006: 24 and Ortigosa, 2012), YUC (Vokes and Vokes, 1983; Distribution: USA (Florida and Texas); Mexico: Sanvicente-Añorve et al., 2012), QROO (Ekdale, 1974); VER (Chávez et al., 1970; Vicencio-de la Cruz and Honduras; Panama; Colombia; Venezuela; Brazil;

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Bermuda; Cuba; Cayman Islands; Jamaica; Puerto Honduras; Colombia; Cayman Islands; Cuba; Jamaica; Rico; Virgin Islands; Guadalupe (Andrews, 1971; Martinique; Puerto Rico; Bermuda (Valdés et al., Valdés et al., 2006). 2006).

Haminoea succinea (Conrad, 1846) Chelidonura cubana Ortea & Martínez, 1997 Examined material: Ycl: 20 specimens (06-05-08), ML Examined material: Sis: 1 specimen 10-06, L 10 mm; 16 mm, over mud (CNMO3041). Mad: 3 specimens (07-05-07), ML 25 mm, over green Diagnosis: Valdés et al., 2006: 26 algae (CNMO2980); 3 specimens (27-08-07), ML 22 Distribution: USA (Florida, Louisiana and Texas); mm, over green algae (CNMO2979). Mexico: VER (García-Cubas, 1971; García-Cubas and Diagnosis: Valdés et al., 2006: 38 Reguero, 1995; Vicencio-de la Cruz and González- Distribution: Cuba; Cayman Islands (Valdés et al., Gándara, 2006; Zamora-Silva and Ortigosa, 2012), 2006). CAMP (Rice and Kornicker, 1962), YUC (Vokes and Vokes, 1983), QROO (Cruz-Abrego et al., 1994); Family Cylincnidae H. Adams & A. Adams, 1854 Colombia; Venezuela; Bermuda; Puerto Rico; St. Acteocina canaliculata (Say, 1826) Martin; St. Bartolomé (Andrews, 1971; Valdés et al., Examined material: Boc: 13 specimens (07-04-08), ML 2006). 6-7 mm, crawling over silt during nocturnal sampling (CNMO3043). Haminoea sp (fig. 2) Diagnosis: Valdés et al., 2006: 16 Examined material: Mad: 3 specimens (20-06-07), L Distribution: USA (Nova Scotia, New Brunswick, 6-8 mm. Maine, Massachusetts, Rhode Island, Connecticut, Diagnosis: Elongate body, with short parapodia New Jersey, Maryland, Virginia, North Carolina, partially covering the shell. Brownish background, South Carolina, Georgia, Florida, Louisiana and Texas) with numerous patch of lighter brown all over the body. (Valdés et al., 2006); Mexico: VER (Flores-Andolais Cylindrical, thin and translucent shell. et al., 1988; Reguero and García-Cubas, 1989; García- Distribution: Thus far, known only from Madagascar Cubas et al., 1990; García-Cubas et al., 1992; Reguero reef, Campeche Bank. and García-Cubas, 1993; García-Cubas and Reguero, Remarks: This is the only species of this genus that 1995), TAB (García-Cubas and Reguero, 1990), YUC was found in a reef. All the others were found in the (Rice and Kornicker, 1962), QROO (Cruz-Ábrego et Bocana lagoon. This species didn´t match the same al., 1994). coloration patterns, neither in the shell nor in the body, Remarks: This species had been reported to live in of the known species of this genus for this geographical areas of sand and seagrass (Redfern, 2001). area Haminoea glabra (Gray, 1825), H. elegans, H. antillarum, and H. succinea (Valdés et al., 2006; Family Gastropteridae Swaison, 1840 Rosenberg et al. 2007). Gastropteron chacmol Gosliner, 1989 Examined material: Mad: 1 specimen (07-05-07), Family Aglajidae Pilsbry, 1895 L 8 mm swimming (Recol. Q. Hernández-Díaz) Chelidonura hirundinina (Quoy & Gaimard, 1833) (CNMO3012); 2 specimens (28-08-07), ML 3 mm, over Examined material: Sis: 1 specimen (10-06), L 20 mm green algae (CNMO3026). (CNMO3032); Mad: 1 specimen (28-08-07), L 18 mm Diagnosis: Gosliner, 1989: 363 (CNMO3034). Distribution: USA (Florida, Texas); Mexico: QROO Diagnosis: Valdés et al., 2006: 38 (Gosliner, 1989; Valdés et al., 2006); Belize; Honduras; Distribution: Indo-Pacific. Western Atlantic: USA Colombia; Venezuela; Brazil; Bahamas; Cayman (Florida); Mexico: YUC (Sanvicente-Añorve et al., Islands (Valdés et al., 2006). 2012); Belize; Colombia; Bahamas; Cayman Islands; Remarks: One of the sampled specimens was found Jamaica; Puerto Rico; Guadeloupe; St. Vincent and the swimming through the water column, as was reported Grenadines; Curaçao; Grenada (Valdés et al., 2006). in the original description (Gosliner, 1989).

Chelidonura berolina Er. Marcus & Ev. Marcus, 1970 Clade Anaspidea Examined material: Sis: 1 specimen (10-06), L 10 Family Aplysiidae Lamarck, 1809 mm. Aplysia brasiliana Rang, 1828 Diagnosis: Valdés et al., 2006: 36. Examined material: Ycl: 3 specimens (31-01-07), ML 6 Distribution: Amphiatlantic. Western Atlantic: Mexico: mm (juveniles) (CNMO2999); 1 specimen (09-05-07), QROO (Á. Valdés, personal communication); Belize; L 120 mm, over green algae; 1 specimen (18-05-07), L

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Figure 3: . Radula of some unidentified species. Chromodoris sp: A) marginal tooth (scale= 30 μm), B) lateral tooth (scale = 50 μm), C) central tooth (scale = 30 μm); D) Okenia sp radula (scale = 30 μm); E) Doto sp radula (scale = 30 μm).

110 mm, under rocks, 14 specimens found dead near St. Lucia; St. Vincent and the Grenadines; Barbados; the water channel; 2 specimens (07-05-08), ML 120 Aruba; Curaçao; Bonaire; Granada; Trinidad and mm one under rock and the other, swimming; Boc: Tobago (Andrews, 1971; Strenth and Blankenship, 7 specimens (07-04-08), ML 140mm, over mud; 3 1977; Valdés et al., 2006). specimens (17-04-08), ML 120 mm, over sand. Aplysia morio (Verrill, 1901) Diagnosis: Valdés et al., 2006: 96 Examined material: Boc: 3 specimens (17-04-08), ML Distribution: Amphiatlantic. Western Atlantic: USA 150 mm, over sand. (New Jersey, Florida and Texas); Mexico: VER (Wiley Diagnosis: Valdés et al., 2006: 98 et al., 1982; Vicencio-de la Cruz and González- Distribution: USA (Rhode Island, Georgia, Florida and Gándara, 2006; Zamora-Silva and Naranjo-García, Texas); Bermuda; Bahamas (Valdés et al., 2006). 2008; Zamora-Silva and Ortigosa, 2012), CAMP (Zamora-Silva and Naranjo-García, 2008), YUC Bursatella leachii pleii Rang, 1828 (Sanvicente-Añorve et al., 2012) Costa Rica; Colombia; Examined material: Boc: 7 specimens (30-01-07), ML 24 Venezuela; Brazil; Bermuda; Aruba (Strenth and mm; 4 specimens (12-04-07), ML 60 mm; 7 specimens Blankenship, 1977; Valdés et al., 2006). (07-04-08), ML 40 mm (CNMO3039). All over mud. Remarks: We observed some recently dead specimens Diagnosis: Valdés et al., 2006: 98 near the water channel of Yucalpeten lagoon, these Distribution: Circumtropical. Western Atlantic: USA seahares tend to get captured in the shrimp fishing nets, (North Carolina, Florida and Texas); Mexico: VER and they are thrown away to avoid further clogging of (Vicencio-de la Cruz and González-Gándara, 2006; the nets. Zamora-Silva and Ortigosa, 2012); CAMP (Zamora- Silva and Naranjo-García, 2008); Belize; Costa Rica; Aplysia dactylomela Rang, 1828 Panama; Colombia; Venezuela; Brazil; Bermuda; Examined material: Boc: 2 specimens (30-01-07), ML Jamaica; Virgin Islands; Aruba; Curaçao; Trinidad 100 mm, over sand; Sis: 1 specimen (22-04-08) L 50 (Andrews, 1971; Strenth and Blankenship, 1977; Valdés mm, over green algae. et al., 2006). Diagnosis: Valdés et al., 2006: 96 Remarks: All the specimens were found on mud during Distribution: Circumtropical. Western Atlantic: USA the low tide, near this area we saw green algae that they (Florida and Texas); Mexico: VER (Moore, 1958; are supposed to feed on (Valdés et al., 2006). Wiley et al., 1982; Quintana y Molina, 1991; García- Cubas et al., 1994; Vicencio-de la Cruz and González- Stylocheilus striatus (Quoy & Gaimard, 1832) Gándara, 2006; Zamora-Silva and Naranjo-García, Examined material: Boc: 2 specimens (17-04-08), L 35 2008; Zamora-Silva and Ortigosa, 2012), CAMP and 40 mm, over mud (Recol. R. Mena) (CNMO3045). (Zamora-Silva and Naranjo-García, 2008); YUC Diagnosis: Valdés et al., 2006: 100 (Sanvicente-Añorve et al., 2012); Belize; Honduras; Distribution: Cosmopolitan. Western Atlantic: USA Costa Rica; Panama; Colombia; Venezuela; Brazil; (Florida and Dry Tortugas); Mexico: VER (Zamora- Bermuda; Cayman Islands; Jamaica; Puerto Rico; Silva and Ortigosa, 2012); YUC (Sanvicente-Añorve Virgin Islands; San Martin; Guadeloupe; Martinique; et al., 2012) Belize; Colombia; Venezuela; Brazil;

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Bermuda; Bahamas; Cayman Islands; Jamaica; Puerto Diagnosis: Carmona et al., 2011 (With molecular Rico; Virgin Islands; Martinique; Barbados; St. Vincent analysis (16s and H3). and the Grenadines; Aruba; Curaçao; Bonaire; Grenada Distribution: USA (Florida); Bahamas; Cuba; Cayman (Valdés et al., 2006). Islands (Ortea et al., 1994; Valdés et al., 2006). Remarks: Elysia cornigera (Nuttall, 1987) from the Phyllaplysia engeli Er. Marcus, 1955 Pacific Ocean and Elysia timida (Risso, 1818) are valid Examined material: Ycl: 1 specimen (09-05-08), L 10 species and sister to each other (Carmona et al., 2011). mm over Thalassia testudinum (CNMO3042). Diagnosis: Valdés et al., 2006: 104 Elysia papillosa Verrill, 1901 Distribution: USA (Florida); Mexico: YUC (Sanvicente- Examined material: Mad: 1 specimen (04-05-07), L 8 Añorve et al., 2012), QROO (Valdés et al., 2006); mm, over green algae. Costa Rica; Colombia; Brazil; Bahamas; Puerto Rico; Diagnosis: Valdés et al., 2006: 64 Jamaica; St. Martin; Barbados; Curaçao (Valdés et al., Distribution: USA (Florida); Mexico: QROO (Á. 2006). Valdés, personal communication); Belize; Honduras; Remarks: The only specimen was found 50 km west of Costa Rica; Panama; Venezuela; Bermuda; Bahamas; the Bocana during an extra expedition that was made Cayman Islands; Guadeloupe; St. Lucia; Martinique; on a Thalassia meadow as it is reported (Valdés et al., Granada; Curaçao; Trinidad and Tobago; (Rios, 1994; 2006). This is one of the two species reported to the Valdés et al., 2006). Caribbean Sea. Elysia subornata Verrill, 1901 Clade Sacoglossa Examined material: Ycl: 1 specimen (31-01-07), L 3 Family Oxynoidae Stoliczka, 1868 mm (CNMO2998), on Caulerpa sp, with egg ribbons Lobiger souberbii P. Fischer, 1857 over the algae. Examined material: Sis: 1 specimen (08-02-07), L 4 Diagnosis: Valdés et al., 2006: 66 mm (CNMO3035). Distribution: USA (Florida); Mexico: VER (Vicencio- Diagnosis: Valdés et al., 2006: 52 de la Cruz and González-Gándara, 2006; Zamora-Silva Distribution: USA (Florida); Mexico: YUC (Vokes and and Ortigosa, 2012), YUC (Sanvicente-Añorve et al., Vokes, 1983), QROO (Ekdale, 1974); Honduras; Costa 2012), QROO (Valdés et al., 2006); Belize; Bermuda; Rica; Venezuela; Cayman Islands; Jamaica; Puerto Bahamas; Cayman Islands; Jamaica; Puerto Rico; Rico; Guadeloupe; Barbados; St. Vincent and the Virgin Islands; Martinique; Aruba; Granada; Trinidad Grenadines; Curaçao (Valdés et al., 2006). and Tobago (Valdés et al., 2006). Remarks: This species is usually found on algae of the Remarks: Valdés et al. (2006) report that this slug feeds genus Caulerpa (Redfern 2001; Valdés et al., 2006) but on the green algae Penicillus dumetosus and Udotea we could not specify the habitat because this species flabellum and Clark (1994) say that this species is were found by an indirect method in a complex of associated with Caulerpa racemosa; we have found it different green algae. on Caulerpa sp.

Family Juliidae E. A. Smith, 1885 Elysia canguzua Er. Marcus, 1955 Berthelinia caribbea Edmunds, 1963 Examined material: Sis: 1 specimen (10-06), L 9 mm Examined material: Mad: 1 specimen (04-05-07), L 3 (CNMO3017). mm (CNMO3028); 2 specimens (07-05-07), ML 3 mm Diagnosis: Valdés et al., 2006: 64 (CNMO3013); 1 specimen (02-05-08), L 3 mm. Distribution: Costa Rica; Brazil (Valdés et al., 2006). Diagnosis: Valdés et al., 2006: 48 Remarks: There are reports of E. canguzua feeding on Distribution: USA (Florida); Mexico: QROO (Á. Valdés, green algae of the genus Codium (Valdés et al., 2006), personal communication); Belize; Costa Rica; Panama; but we did not identify the substrate were we found it. Bahamas; Jamaica; Puerto Rico; Brazil (Valdés et al., 2006). Remarks: This species is frequently associated with the Elysia tuca Ev. Marcus & Er. Marcus, 1967 green algae Caulerpa verticillata (Clark et al., 1990). Examined material: Sis: 1 specimen (10-06), L 9 mm We found it with a variety of green algae. (CNMO3019). Diagnosis: Valdés et al., 2006: 66 Family Placobranchidae Gray, 1840 Distribution: USA (Florida); Mexico: YUC (Sanvicente- Elysia cf. cornigera Añorve et al., 2012), QROO (Valdés et al., 2006); Examined material: Ycl: 2 specimens (31-01-07), ML 4 Honduras; Costa Rica; Panama; Colombia; Brazil; mm (CNMO2995). Bermuda; Cayman Islands; Jamaica; Puerto Rico;

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Table 1: Previous studies in the Atlantic Coast of Mexico not cited in Rosenberg et al. 2007.

Study area Author Year Veracruz Flores-Andolais et al. 1988 Quintana y Molina 1991 Reguero and García-Cubas 1993 Vicencio-de la Cruz and González-Gándara 2006 Zamora and Ortigosa 2012 Tabasco García-Cubas and Reguero 1990 Quintana Roo Cruz-Ábrego et al. 1994 Gulf of Mexico Pérez-Rodríguez 1997 Zamora-Silva and Naranjo-García 2008 Campeche Bank Sanvicente-Añorve et al. 2012 Atlantic Malaquias and Reid 2007

Virgin Islands; San Martin; St. Lucia; St. Vincent and Family Limapontiidae Gray, 1847 the Grenadines; Barbados; Curaçao; Grenada (Valdés Ercolania sp (fig. 2) et al., 2006). Examined material: Mad: 14 specimens (28-08-07), Remarks: It is reported that this species is usually found ML 2 mm, over ribbons of eggs attached to a coral on the green algae Halimeda. We could not identify the (CNMO2968). substrate. Diagnosis: light green body with dark green cerata all over the body except for the head. Small white dots Elysia patina Ev. Marcus, 1980 through all the ceratas. Smooth rhinophores. Ceratas Examined material: Sis: 1 specimen (27-04-07), L not so dense, leaving the dorsum clear. 10 mm; Mad: 1 specimen (07-05-07), L 8 mm, over Distribution: Thus far, known only from Madagascar Halimeda sp; 1 specimen (23-02-07), L 9 mm. reef, Campeche Bank. Diagnosis: Valdés et al., 2006: 72 Remarks: Here are four species of Ercolania in the Gulf Distribution: USA (Florida); Mexico: YUC (Sanvicente- of Mexico and the Caribbean Sea. The sampled material Añorve et al., 2012), QROO (Valdés et al., 2006); did not have a purple spot over the head as E. viridis A. Costa Rica; Bahamas; Martinique; St. Vincent and the Costa, 1866; nor the black points of E. fuscata (Gould, Grenadines (Valdés et al., 2006). 1870); the ceratas are not so numerous as in E. courulea Remarks: One specimen of this species was found in Trinchese, 1872, and was described for the Atlantic east Halimeda sp, in contrast with reports of finding it on so the distribution and identification must be reviewed; Udotea sp. (Valdés et al., 2006). finally, Rosenberg et al. (2007) reported E. fuscovittata (Lance, 1962) as an introduced species in Florida from Elysia zuleicae Ortea & Espinosa, 2002 East Pacific. Such lack of characters can be due to the Examined material: Sis: 2 specimens (23-02-07), ML small size of the sampled specimens (1-2 mm). Species 18 mm, over green algae. of these genera had been reported to be on Caulerpa Diagnosis: Valdés et al., 2006: 70 racemosa (Clark et al., 1990). However, the collected Distribution: Costa Rica; Cuba; Jamaica (Valdés et al., specimens were found over ribbons of eggs, as some 2006). species of limapontiids (Gosliner et al., 2008).

Thuridilla mazda Ortea & Espinosa, 2000 Costasiella ocellifera (Simroth, 1895) Examined material: Mad: 1 specimen (06-06-07), L 13 Material: Sis: 10 specimens (10-06), ML 8 mm mm, over Caulerpa sp (CNMO3027). (CNMO3020); 6 specimens (27-04-07), ML 6 mm Diagnosis: Valdés et al., 2006: 58 (CNMO2993); 5 specimens (06-03-08), ML 4 mm; Distribution: Costa Rica; Bahamas; Cuba (Valdés et Mad: 3 specimens (11-06-07), ML 7 mm (CNMO3002); al., 2006). Portugal (Azores) (Malaquias et al., 2012) 4 specimens (11-04-08), ML 5 mm. All over the green

66 Thalassas, 29(1) · January 2013 SEASLUGS (Mollusca: Opisthobranchia) FROM CAMPECHE BANK, YUCATAN PENINSULA, MEXICO

algae Avrainvillea longicaulis. Diagnosis: (Valdés et al., 2006: 152) Diagnosis: Valdés et al., 2006: 78 Distribution: Costa Rica; Martinique; St. Vincent and Distribution: USA (Florida); Mexico: YUC (Sanvicente- the Grenadines (Valdés et al., 2006). Añorve et al., 2012), QROO (Á. Valdés, personal Radular formula: 47x26-27.0.26-27 communication); Belize; Honduras; Costa Rica; Brazil; Remarks: All the sampled material was collected on Bermuda; Bahamas; Cayman Islands; Puerto Rico; sponges, in contrast with Valdes et al (2006) that report Jamaica; St. Martin; Martinique; St. Lucia; St. Vincent finding it in rocky bottoms. and the Grenadines; Granadas (Valdés et al., 2006). Remarks: Valdés et al. (2006) report that this species Chromodoris sp (fig.2, 3) lives and feeds on the surface of Avrainvillea longicaulis. Examined material: Sis: 1 specimen (02-03-07), L 12 mm. This alga was found randomly distributed in the studied Diagnosis: Yellow-white elongated and flat body with area in low densities and all the specimens of this small brown spots randomly through all the dorsum. species were found there. Not all of the branches of the Big tubercles over the entire mantle. Large perfoliate algae have this species of opisthobranch. tubercles. The gill is in the posterior part of the body. Distribution: Thus far, known only from Sisal reef, Placida dendritica (Alder & Hancock, 1843) Campeche Bank. Examined material: Sis: 8 specimens (08-02-07), ML 3 Remarks: Radular formula 33x42-43.0.42-43. This mm (CNMO3018). species didn´t match the orange, purple and red Diagnosis: Valdés et al., 2006: 82 coloration patterns of C. clenchi, C. binza Ev. Marcus & Distribution: Cosmopolitan. Western Atlantic: USA Er. Marcus, 1963, C. ponga Er. Marcus & Ev. Marcus, (North Carolina); Costa Rica; Jamaica; Curaçao 1970; the reticulated dorsum of C. neona (Er. Marcus, (Valdés et al., 2006). 1955); the orange and white species as C. grahami Thompson, 1980, C. regalis (Ortea, Caballer & Moro, Clade Cryptobranchia 2001), and the irregular spots of Chromodoris sp. image Family Dorididae Rafinesque, 1815 of Valdés et al. (2006) Doris bovena Er. Marcus, 1955 Examined material: Ycl: 2 specimens (10-06), ML 14 Hypselodoris picta (Schultz, 1836) mm, over sponges (CNMO2965). Examined material: Sis: 8 specimens (10-06), ML 100- Diagnosis: Valdés et al., 2006: 170 140 mm, over algae; 1 specimen (08-02-07), L 120 mm, Distribution: USA (Florida); Mexico: YUC (Sanvicente- over sand; 1 specimen (27-04-07), L 110 mm, over soft Añorve et al., 2012); Honduras; Venezuela; Brazil; coral; 1 specimen (28-05-07), L 100 mm, over sponges Aruba; Curaçao (Valdés et al., 2006). (CNMO2989); Mad: 1 specimen (08-06-07), L 45 mm, Radular formula. 30x30.0.30 over green algae; 2 specimens (11-06-07), ML 47 mm, over green algae (CNMO3001); 1 specimen (20-06-07), Family Chromodorididae Bergh, 1891 L 40 mm, over sand (CNMO3005); 1 specimen (27-08- Chromodoris clenchi (Rusell, 1935) 07), L 30 mm, over sand (CNMO3008); 5 specimens Examined material: Sis: 1 specimen (10-06), L 6 mm, (06-03-08), ML 100 mm, over green algae. over sponges; Mad: 3 specimens (28-08-07), ML 15 Diagnosis: Valdés et al., 2006: 154 mm (CNMO2992), on green algae; 2 specimens (30- Distribution: Amphiatlantic. Western Atlantic: USA 08-07), ML 20 mm, over green algae (CNMO3003); (Florida); Brazil (Valdés et al., 2006). 5 specimens (05-09-07), ML 22 mm, over green algae Remarks: Due to its dark color and large size, it was (CNMO3009). found in many sites. Diagnosis: Valdés et al., 2006: 148 Distribution: USA (Florida); Costa Rica; Panama; Hypselodoris acriba Ev. Marcus & Er. Marcus, 1967 Colombia; Bermuda; Cayman Islands; Jamaica; St. Examined material: Mad: 4 specimens (07-05-07), ML Lucia; St. Vincent and the Grenadines; Curaçao (Valdés 18-40 mm over green algae (CNMO3014); 1 specimen et al., 2006). (06-06-07), L 34 mm, over coral (CNMO2990); 1 specimen, (08-06-07), L 22 mm, over green algae; 2 Chromodoris regalis (Ortea, Caballer & Moro, 2001) specimens (11-06-07), ML 25 mm, over green algae; Examined material: Mad: 3 specimens (08-06-07), 1 specimen (30-08-07), L 21 mm, over green algae ML 10 mm, (Recol. Q. Hernández-Díaz); 3 specimens (CNMO3004); 1 specimen (05-09-07), L 21 mm, over (20-06-07), ML 12 mm; 18 specimens (28-08-07), green algae; 1 specimen (11-04-08), L 40 mm, over ML 22 mm; 8 specimens (05-09-07), ML 23 mm orange sponge; 1 specimen (24-04-2008), L 40 mm, (CNMO3025). All over purple-reddish sponges. over green algae; Ser: 1 specimen (28-05-07), L 25 mm,

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Table 2: Reef sites

Localities Distance to coast (km) Area (km2) Deep (m) Serpiente 53 0.046 7-18 Madagascar 40 0.216 4-13 Sisal 23 0.673 3-10

over green algae; 1 specimen (30-05-07), L 40 mm, Family Dendrodorididae O´Donoghue, 1924 over red algae. Dendrodoris krebsii (Mörch, 1863) Diagnosis: Valdés et al., 2006: 160 Examined material: Ycl: 2 specimens (10-06), ML 45 Distribution: Mexico: QROO (Ortea et al., 1996); Costa mm, over orange sponges; 1 specimen (31-01-07), L 50 Rica; Puerto Rico; San Martin; Guadeloupe; Santa mm; 3 specimens (28-02-07), ML 60 mm; 2 specimens Lucia (Valdés et al., 2006). (09-05-07), ML 40-50 mm; 2 specimens (18-05-07), ML 60 mm (CNMO3010); 14 specimens (07-05-08), Hypselodoris ruthae Ev. Marcus & Hughes, 1974 ML 55-60 mm; Sis: 1 specimen (21-04-08), L 40 mm, Examined material: Mad: 1 specimen (28-08-07), L 13 under rocks. mm, over green algae; 1 specimen (05-09-07), L 25 mm Diagnosis: Valdés et al., 2006: 198. over green algae. Distribution: USA (Georgia and Florida); Mexico: YUC Diagnosis: Valdés et al., 2006: 156 (Sanvicente-Añorve et al., 2012), QROO (Á. Valdés, Distribution: Mexico: QROO (Ortea et al., 1996; Valdés personal communication); Belize; Honduras; Costa Rica; et al., 2006); Costa Rica; Venezuela; Bahamas; Cuba; Panama; Colombia; Venezuela; Brazil; Bahamas; Cuba; Jamaica; Puerto Rico; Virgin Islands; San Martin; Dominic Republic; Cayman Islands; Jamaica; Virgin Antigua; Guadeloupe; Martinique; St. Lucia; Barbados; Islands; San Martin; Antigua; Guadeloupe; Martinique; Aruba; Curaçao; Grenada (Valdés et al., 2006). St. Lucia; St. Vincent and the Grenadines; Barbados; Granada; Aruba; Curaçao (Valdés et al., 2006). Felimare kempfi (Ev. Marcus, 1971) Remarks: This is one of the most common nudibranch Examined material: Ser: 1 specimen (28-05-07), L 14 in the Caribbean (Valdés et al., 2006). We found them mm, over sand; Mad: 3 specimens (27-08-07), ML 8 both in coral reefs and in lagoons. mm, over green algae (CNMO3007). Diagnosis: Valdés et al., 2006: 166 Family Goniodorididae H. Adams & A. Adams, 1854 Distribution: USA (Florida); Mexico: QROO (Valdés Okenia sp (fig. 2, 3) et al., 2006); Panama; Costa Rica; Brazil; Puerto Rico Examined material: Sis: 2 specimens (23-02-07), L 8 (Rios, 1994; Valdés et al., 2006). mm (CNMO3038). Remarks: This species was found over green alga; Diagnosis: Translucent white body. White, brown, and nevertheless it has been reported on calcareous algae. red small papiles over the body. Lamellate rhinophores, posterior part of the same color as the body. Short oral Felimare sisalensis Ortigosa & Valdés, 2012 tentacles. Examined material: Mad: 3 specimens (05-09-07), L Distribution: Thus far, known only from Sisal reef, 12 mm (CNMO2981), L 11 mm (LACM3223), L12 mm Campeche Bank. (CNMO3037), all over green algae Remarks: This species didn´t match the same coloration Diagnosis: Ortigosa and Valdés, 2012: 101. patterns, shape and length of the papillae of the known Distribution: Thus far, known only from Madagascar species of this genus for this geographical area; Okenia reef, Campeche Bank. zoobotryon (Smallwood, 1910) have dark purple and pale brown spots all over the body; Okenia evelinae Family Discodorididae Bergh, 1891 Er. Marcus, 1957 its white and their rhinophores are Jorunna spazzola (Er. Marcus, 1955) partially purple; Okenia impexa Er. Marcus, 1957 is Examined material: Boc: 1 specimen (30-01-07), L 15 yellow and has large papillae; Okenia miramarea Ortea mm, under rocks. & Espinosa, 2000 (in Valdés et al., 2006); Okenia sp. Diagnosis: Valdés et al., 2006: 184 1 (in Valdés et al., 2006) is yellow and have wide and Distribution: USA (Florida); Honduras; Brazil; Cuba; short papillae; Okenia sp. 2 and Okenia sp. 3 have a Barbados; Virgin Islands; Curaçao (Valdés et al., white green translucent body,and the papillaes are long 2006). and shorter, respectively.

68 Thalassas, 29(1) · January 2013 SEASLUGS (Mollusca: Opisthobranchia) FROM CAMPECHE BANK, YUCATAN PENINSULA, MEXICO

Family Polyceridae Alder & Hankock, 1845 divae Ev. Marcus & Er. Marcus, 1950, D. sabuli Ortea, Tambja cf. tenuilineata Miller & Haagh, 2005 (fig. 2, 3) 2001, and D. cabecar Ortea, 2001; the large apical Examined material: Mad: 1 specimen (07-05-07), L 13 tubercles and white spots on the dorsum of D. chica Ev. mm; 1 specimen (27-08-07), L 4 mm, over green algae; Marcus & Er. Marcus, 1960; and the white color, dense Ser: 1 specimen, (30-05-07), L 2 mm. and large tubercles of D. varaderoensis Ortea, 2001. Diagnosis: Miller and Haagh, 2005 It´s important to notice that there are disagreements between the identity and description of some Caribbean Placida dendritica (Alder & Hancock, 1843) species (Valdés et al., 2006). Examined material: Sis: 8 specimens (08-02-07), ML 3 Family Scyllaeidae Alder & Hancock, 1855 mm (CNMO3018). Scyllaea pelagica Linnaeus, 1758 Diagnosis: Valdés et al., 2006: 82 Examined material: Sis: 1 specimen (23-02-07), L 8 Distribution: Australia (New South Wales, Southern mm (CNMO3021). Queensland and Lord Howe Island); New Zealand Distribution: Circumtropical. Western Atlantic: USA (Miller and Haagh, 2005); Portugal (Azores) (Wirtz, (Massachusetts, North Carolina, Georgia, Florida, 1998, as Tambja sp.). Texas); Mexico: YUC (Sanvicente-Añorve et al., 2012); Remarks: The known distribution of this species is Costa Rica; Bermuda; Bahamas; Bonaire (Valdés et very disjunctive; it was described in Australia, and al., 2006). it has been also recorded in the Azores Islands in Remarks: This species inhabits on floating Sargassum the middle of the North-Atlantic Ocean. Here it is sp, here we found it by a brushing method over different reported for first time for the western Atlantic. The species of algae. coloration pattern of the specimens is the same as the original description. Nevertheless, molecular or Family Flabellinidae Bergh, 1881 taxonomical dissection will be necessary in order of Flabellina dushia (Ev. Marcus & Er. Marcus, 1963) confirm its identity. Examined material: Mad: 1 specimen (11-04-08), L 10 mm, over green algae. Clade Cladobranchia Diagnosis: Valdés et al., 2006: 238 Falimy Dotidae Gay, 1853 Distribution: USA (Florida); Bahamas; Jamaica; Doto sp Martinique; Curaçao (Valdés et al., 2006). Examined material: Mad: 1 specimen (06-06-07), L 11 mm (CNMO3033). Flabellina engeli Ev. Marcus & Er. Marcus, 1968 Diagnosis: Small elongated brownish green body. Examined material: Mad: 1 specimen (24-04-08), L 14 Rhinophoral sheaths with pulpital shape, also brownish mm, over red-purple sponge. green. Smooth rhinophores. Tuberculate cerata arranged Diagnosis: Valdés et al., 2006: 240 dorso-laterally on each side of the body, the anterior Distribution: USA (Florida); Costa Rica; Colombia; ceratas are smaller and with a simpler arrangement Cuba; Puerto Rico; Martinique; St. Lucia; Barbados; than the posterior ones. The base of the cerata is Curaçao; Grenada (Valdés et al., 2006). lighter brown through all the body. Irregular tubercles distributed through all the body (fig. 2). Radula with a Flabellina sp (fig. 9) single row. The reproductive system has one receptacle Examined material: Ycl: 2 specimens (28-02-07), ML with an unknown function. 12 mm. Radular formula: 79x1.0.1 (fig 3). Diagnosis: White elongated body with a slightly more Distribution: Thus far, known only from Madagascar translucent foot than the rest of the body. With an reef, Campeche Bank. opaque white dorsal line across the body, it is wider in Remarks: This species didn´t match with the coloration the pericardial area. Oral tentacles the same color as the patterns, or the shape and size of the ceratas of the 14 body and with translucent tips. The anterior corner of known species of this genus for this geographical area: the foot is small, triangular, and of the same color as the the orange color of the ceratas of D. uva Er. Marcus foot. Smooth white rhinophores. Numerous and densely 1955, D. wildeli Er. Marcus & Ev. Marcus, 1970, and arranged cerata, without forming clusters, the digestive D. duao, Ortea, 1955; the flat ceratas of D. pita Er. gland is orange with scattered opaque white spots. Marcus, 1955 and Doto sp 1 (in Valdes et al., 2006; Distribution: Thus far, known only from Yucalpeten the dark body and rounded ceratas of D. escatlari lagoon, Campeche Bank. Ortea, Moro & Espinosa, 1997, Doto sp 2 (in Valdés Remarks: The collected material could be attributed et al., 2006), and Doto sp 3 (in Valdés et al., 2006); the Flabellina verta (Er. Marcus, 1976) or Flabellina particular coloration of Doto pygmaea Bergh, 1871, D. bandeli (Ev. Marcus, 1976); nevertheless, the diagnosis

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Table 3: Opisthobranch species sampled in the Yucalpeten and the Bocana lagoons, and in Sisal, Madagascar, and Serpiente coral reefs (NR=New record).

f c coast o i ant

Family Species l t Sisal A Mexico Mexico Serpiente Serpiente La Bocana La Bocana Yucalpeten Yucalpeten Madagascar Madagascar rom f NR for Yucatan State State NR for Yucatan NR

Clado Cephalaspidea Bullidae Bulla occidentalis Adams, 1850 Ɣ Ɣ Haminoeidae Haminoea elegans (Gray, 1825) Ɣ Haminoea antillarum (d´Orbigny 1841) Ɣ Haminoea succinea (Conrad, 1846) Ɣ Haminoea sp Ɣ Ɣ Ɣ Aglajidae Chelidonura hirundinina (Quoy and Gaimard, 1833) Ɣ Ɣ Chelidonura berolina Er. Marcus and Ev. Marcus, 1970 Ɣ Ɣ Ɣ Chelidonura cubana Ortea and Martínez, 1997 Ɣ Ɣ Ɣ Ɣ Cylichnidae Acteocina canaliculata (Say, 1826) Ɣ Gastropteridae Gastropteron chacmol Gosliner, 1989 Ɣ Ɣ Clado Aplysiomorpha Aplysiidae Aplysia brasiliana Rang, 1828 Ɣ Ɣ Aplysia dactylomela Rang, 1828 Ɣ Ɣ Aplysia morio (Verrill, 1901) Ɣ Ɣ Ɣ Bursatella leachii pleii Rang, 1828 Ɣ Ɣ Stylocheilus striatus (Quoy and Gaimard, 1832) Ɣ Phyllaplysia engeli Er. Marcus, 1955 Ɣ Clado Sacoglossa Oxynoidae Lobiger souverbii P. Fischer, 1857 Ɣ Juliidae Berthelinia caribbea Edmunds, 1963 Ɣ Ɣ Placobranchidae Elysia cf. cornigera (Nuttall, 1989) Ɣ Ɣ Ɣ Elysia papillosa Verrill, 1901 Ɣ Ɣ Elysia subornata Verrill, 1901 Ɣ Elysia canguzua Er. Marcus, 1955 Ɣ Ɣ Ɣ Elysia tuca Ev. Marcus y Er. Marcus, 1967 Ɣ Elysia patina Ev. Marcus, 1980 Ɣ Ɣ Ɣ Elysia zuleicae Ortea y Espinosa, 2002 Ɣ Ɣ Ɣ Thuridilla mazda Ortea y Espinosa, 2000 Ɣ Ɣ Ɣ Limapontiidae Ercolania sp Ɣ Ɣ Ɣ Costasiella ocellifera (Simroth, 1895) Ɣ Ɣ Placida dendritica (Alder y Hancock, 1843) Ɣ Ɣ Ɣ Clade Eutenidiacea Dorididae Doris bovena Er. Marcus, 1955 Ɣ Chromodorididae Chromodoris clenchi (Rusell, 1935) Ɣ Ɣ Ɣ Ɣ Chromodoris regalis (Ortea, Caballer & Moro, 2001) Ɣ Ɣ Ɣ Chromodoris sp Ɣ Ɣ Ɣ Hypselodoris picta (Schultz, 1836) Ɣ Ɣ Ɣ Ɣ Ɣ Hypselodoris acriba Ev. Marcus y Er. Marcus, 1967 Ɣ Ɣ Ɣ Hypselodoris ruthae (Ev. Marcus y Hughes, 1974) Ɣ Ɣ Felimare kempfi (Ev. Marcus, 1971) Ɣ Ɣ Ɣ Felimare sisalensis Ortigosa & Valdés, 2012 Ɣ Ɣ Ɣ Discodorididae Jorunna spazzola (Er. Marcus, 1955) Ɣ Ɣ Ɣ Dendrodorididae Dendrodoris krebsii (Mörch, 1863) Ɣ Ɣ Goniodorididae Okenia sp Ɣ Ɣ Ɣ Polyceridae Tambja cf. tenuilineata Miller y Haagh, 2005 Ɣ Ɣ Ɣ Ɣ Clado Cladobranchia Dotidae Doto sp Ɣ Ɣ Ɣ Scyllaeidae Scyllaea pelagica Linnaeus. 1758 Ɣ Flabellinidae Flabellina dushia (Ev. Marcus y Er. Marcus, 1963) Ɣ Ɣ Ɣ Flabellina engeli Ev. Marcus y Er. Marcus, 1968) Ɣ Ɣ Ɣ

Flabellina sp Ɣ Ɣ Ɣ Aeolidiidae Aeolidiella stephanieae Valdés, 2005 Ɣ Aeolidiella sp 1 Ɣ Ɣ Ɣ Aeolidiella sp 2 Ɣ Ɣ Ɣ Spurilla neapolitana (delle Chiaje, 1841) Ɣ Ɣ 

70 Thalassas, 29(1) · January 2013 SEASLUGS (Mollusca: Opisthobranchia) FROM CAMPECHE BANK, YUCATAN PENINSULA, MEXICO

Table 4: Richness species of opisthobranchs in different areas.

Area Cephalaspidea Sacoglossa Aplysiomorpha Notaspidea Nudibranchia Reference Caribbean 29% 15.6% 5.2% 4.6% 45.7% Bertsch, 2009 Brazil 25.9% 10% 6.3% 5.4% 50.7% Bertsch, 2009 Colombia 32.47% 6.49% 24.29% ? 40.26% Ardila et al., 2007 Campeche 16.92% 24.62% 12.31% 0% 46.15% (Eutenidiacea+ Sanvicente-Añorve et Bank Cladobranchia) al., 2012, this study of those species didn´t show concluding differences Spurilla neapolitana (delle Chiaje, 1841) between each one and both match with our specimen. Examined material: Boc: 1 specimen (30-01-07), L 12 mm, under ro ck; Ycl: 1 specimen (31-01-07), L 10 Family Aeolidiidae Gray, 1827 mm, under rock; 3 specimens. (28-02-07), ML 22 mm, Aeolidiella stephanieae Valdés, 2005 over brown algae; 3 specimens (18-05-07), ML 18 mm, Examined material: Ycl: 1 specimen (28-02-07), L 9 under rock. mm (CNMO2996); 1 specimen (18-05-07), L 10 mm, Diagnosis: Valdés et al., 2006: 270 both beneath rocks. Distribution: Circumtropical. Western Atlantic: USA Diagnosis: Valdés et al., 2006: 274 (Florida and Texas); Mexico: VER (Zamora-Silva and Distribution: USA (Florida) (Valdés et al., 2006); Ortigosa, 2012), YUC (Sanvicente-Añorve et al., 2012); Mexico: YUC (Sanvicente-Añorve et al., 2012). Belize; Honduras; Costa Rica; Colombia; Venezuela; Remarks: This species feeds on sea anemones (Valdés Brazil Bahamas; Bermuda; Virgin Islands; Jamaica; et al., 2006). Puerto Rico; Barbados; St. Vincent and the Grenadines; Curaçao (Valdés et al., 2006). Aeolidiella sp 1 (fig. 2) Remarks: This species feeds on anemones of the genus Examined material: Mad: 1 specimen (06-06-07), L 15 Aiptasia (Valdés et al., 2006). mm, over Padina sp. Diagnosis: Opaque white elongated body with foot DISCUSSION slightly wider than the rest of the body and translucent white. Oral tentacles orange and well developed. The The information of the distribution of these species anterior corner of the foot is small, triangular, and of partially fills the information gap of this group of the same color as the rest of the foot. Smooth orange gastropods in the Campeche Bank, Yucatan Peninsula, rhinophores with no other sculpture. Numerous and a very interesting transition area between the Gulf of densely arranged cerata, without forming groups, the Mexico and the Caribbean Sea. The number of species digestive gland of brownish color with white tips. registered during this survey is the result of the sampling Distribution: Thus far, known only from Madagascar effort focused exclusively in this group of mollusks. reef, Campeche Bank. The number of species recorded here is higher than those found by Zamora Silva and Ortigosa (2012), and Aeolidiella sp 2 (fig. 2) Sanvicente-Añorve et al. (2012), since the habitats Examined material: Mad: 1 specimen (05-09-07), L 14 studied here include two different areas (lagoons and mm, over green algae. reefs), and also due to the use of SCUBA equipment. Diagnosis: Opaque white elongated body with a The indirect methods were the best to find small, cryptic translucent white foot. White Oral tentacles, well and shell-less species, as it can be confirmed in Table developed with a translucent white base. Smooth 3. The methods used in the present study prevented opaque white rhinophores with no other sculpture, damage to the fragile body structures of the shell-less with a white translucent base. Numerous and densely species, enabling the observation of complete and intact arranged cerata, without forming groups, red digestive morphological characteristics. To date, almost all the gland with white tips. opisthobranch species reported for the Atlantic coast of Distribution: Thus far, known only from Madagascar Mexico were those having a well-developed calcareous reef, Campeche Bank. shell such as J. punctostriatus, B. occidentalis, and A. Remarks: The two species of Aeolidiella didn´t match canaliculata those with large size such as A. dactylomela the same coloration patterns of any of the known and A. brasiliana (Zamora-Silva and Ortigosa, 2012). species of this genus for this geographical area A. and only the study of Sanvicente-Añorve et al. (2012) indica Bergh, 1988, A. benteva (Er. Marcus, 1958), and reported cryptic and small species. The shelled seaslugs A. stephanieae. are well preserved in sand and mud samples, and

Thalassas, 29(1) · January 2013 71 DENEB ORTIGOSA, NUNO SIMÕES & GONÇALO CALADO

the larger ones could be easily observed, leaving the richness of this particular taxa. As expected, due to the cryptic species undiscovered. Nevertheless, there are spatial distribution of the sampling stations we found still places that were not sampled, such as live coral, opisthobranch species that had already been reported in sand beaches or mangroves swamps, and therefore, the the Caribbean and in the Gulf of Mexico, as it happens number of species could increase in the future. Out of with other species of invertebrates that share species the 51 species of seaslugs reported in this study, six between regions (González et al., 1991; Gutiérrez et al., species have no shell and 17 species were 16 mm or 1993; Jordán-Dahlgren, 2002). less of total length in the adult stage. This could be the first record of T. cf. tenuilineata for the east coast of the From the 18 total species found in the lagoons, only Atlantic Ocean; it has been reported only in the Azores three species were shared between both lagoons (B. Islands (Wirtz, 1998) and in Australia (Miller and occidentalis, A. brasiliana, and S. neapolitana), each Haagh, 2005). Sisal village has an small harbor, almost one of different clades (Cephalaspidea, Aplysiomorpha, confined to fishermen of the village, due to this, T. cf. and Cladobranchia). Similarly, from the 35 species total tenuilineata could be introduced by ships that arrived found in the three reefs, only two (E. patina and H. to the Progreso Harbor (eastern of the study sites). The picta) are shared between them from two different clades present checklist includes 23 species of seaslugs that are (Sacoglossa and Eutenidiacea). This could be due to the new records for the Mexican Atlantic coast (including great diversity of the feeding resources inside the group Gulf of Mexico and Caribbean Sea). Compared with (Nybakken, 1974; McDonald and Nybakken, 1991, 1997, Sanvicente-Añorve et al. (2012), only 17 species were 1999) and despite some similar habitats between each shared between studies suggesting possible differences reef and between lagoons; there are differences in the between the reefs. Nonetheless, efforts must be made feeding resources. The nudibranch D. krebsii is reported to improve the knowledge of the seaslug fauna of the as common in the Caribbean (Valdes et al., 2006) but we Campeche bank. only found it in seven out of the 57 sampled sites; and Elysia crispata Mörch, 1863, distributed in Veracruz In this study the clade Sacoglossa has the reefs (Zamora-Silva and Ortigosa, 2012), at Alacranes highest specific richness, followed by Eutenidiacea, reef (Sanvicente-Añorve et al. 2012), and at Mexican Cephalaspidea, Aeolidina, Anaspidea, and Cladobranchia. Caribbean (Á. Valdés, personal communication) was not The Eutenidiacea+ Cladobranchia group (Nudibranchia) recorder in this study. were the most diverse with almost the half of the records, as happens with other studies at the Campeche Bank According to Johnson and Gosliner (2012), all the (Sanvicente-Añorve et al., 2012), Caribbean Sea (Bertsch, Atlantic species of the Chromodoris genera have to 2009), Colombia (Ardila et al., 2007), and Brazil (Bertsch, be named as Felimida Marcus, 1971, and the species 2009) (Table 5). The diversity of the other clades differed from the eastern Pacific, Atlantic, and Mediterranean between the areas. In this study, Notaspidea species were known as Hypselodoris, and the eastern Pacific and not found, as in Sanvicente-Añorve et al. (2012), although Atlantic Mexichromis are part of Felimare clade, but the group is reported in the warm Atlantic waters of due to the lack of molecular analysis in this study, Colombia and Brazil (Valdés et al., 2006; Ardila et al. we conserved the traditional names. The species of 2007; Bertsch 2009). traditionally Mexichromis in this study are named as Felimare according to Johnson and Gosliner (2012) and From the entire species recorded, seven have a Ortigosa and Valdés (2012). widespread distribution (A. dactylomela, B. leachii pleii, S. striatus, L. souverbii, P. dendritica, S. pelagica, and As the objective of the present study was to update S. neapolitana), and two are recorded for the Atlantic the opisthobranch fauna inventory of the Campeche Bank, and Pacific coasts of Mexico (C. hirundinina, and L. Yucatan Peninsula, the lack of a quantitative sampling souverbii). effort (using transects or quadrants), did not compromised the results, and indeed, the use of direct sampling using Out of the 111 species of opisthobranch reported for different collection techniques increased the rare and the Atlantic Mexican coast, 37 were reported for the Gulf cryptic species numbers. of Mexico, 36 for the Mexican Caribbean, and 20 of the records do not specified the locality (Valdés et al., 2006). The adequate knowledge of the biodiversity With the contribution of the present study, the actual of a specific area is critical for the establishment or number of opisthobranch fauna in the Campeche Bank management of conservation areas. Very large areas increases to 84 species, representing a 64% increment of the Mexican Atlantic coast remain unexplored for of the biodiversity knowledge on the region’s species opisthobranchs fauna and these represent not only great

72 Thalassas, 29(1) · January 2013 SEASLUGS (Mollusca: Opisthobranchia) FROM CAMPECHE BANK, YUCATAN PENINSULA, MEXICO

challenges to increase our knowledge of this particular comunidades bentónicas del arrecife de Lobos, Veracruz, taxa in the region, but it also poses difficult logistic Revista de la Sociedad Mexicana de Historia Natural, 31: obstacles. Areas such as the Veracruz reefs at the western- 211-280. central part of the Gulf of Mexico, the many cays of Clark K, Jensen K, Stirts H (1990). Survey for functional the Campeche Bank, the Mesoamerican Reef in the kleptoplasty among West Atlantic Ascoglossa (=Sacoglossa) Caribbean sea, and a diverse system of coastal lagoons (Mollusca: Opisthobranchia), The Veliger, 30(4): 339-345. creates great opportunities for future opisthobranch fauna Clark, K (1994) Ascoglossan (=Sacoglossa) mollusks in the surveys and to increase the group species richness in the Florida Keys: rare marine invertebrates at special risk, region. Bulletin of Marine Science, 54(3): 900-916. Cruz-Ábrego FM, Toledano-Granados A, Flores-Andolais F ACKNOWLEDGEMENTS (1994). Ecología comunitaria de los gasterópodos marinos (Mollusca: Gastropoda) en Isla Contoy, Revista de Biología We want to thank CONACyT for the M. Sc. scholarship Tropical, 42: 549-556. through the Posgrado de Ciencias del Mar y Limnología, Ekdale AA (1974). Marine molluscs from the shallow-water Universidad Nacional Autónoma de México (PCMyL, environments (0-60 meters) off the northeast Yucatan coast, UNAM) (202617); Ecology research group of UMDI- Mexico, Bulletin of Marine Science, 24(3): 638-668. Sisal, UNAM (M. Badillo, A. Gallardo, M. Mascaró, Flores-Andolais F, García-Cubas A, Toledano-Granados A J. Aranda, Q. Hernández, S. Zarco, M. Oseguera, F. (1988). Sistemática y algunos aspectos ecológicos de los Mex); Dr. Ángel Valdés, California State Polytechnic moluscos de la Laguna de la Mancha, Veracruz, México, University, Pomona; Natural History Museum of Los Anales del Instituto de Ciencias del Mar y Limnología, Angeles County (SEM); M. Reguero, B. Urbano, and 175(2):235-258 S. Biro, UNAM; the Biology group of Universidade García-Cubas A (1971). Ecología and distribución de los Lusófona de Humanidades e Tecnologias (F. Carlos, M. micromoluscos de la Laguna de Tamiahua, Veracruz, Albuquerque, C. Cúcio, P. Coelho). This work was funded México, Universidad Nacional Autónoma de México, by the UNAM (PAPIME PE207210) and CONACyT- Boletín del Instituto de Geología, 91: 1-53. SEMARNAT (108285 Project). García-Cubas A, Escobar F, González L, Reguero M (1990). Moluscos de la Laguna de Mecoacan, Tabasco, México: REFERENCES Sistemática y ecología, Anales del Instituto de Ciencias del Mar y Limnología, 17(2): 309-343. Abascal AJ, Sheinbaum J, Candela J, Ochoa J, Badan A García-Cubas A, Escobar F, Reguero M (1999). Gastrópodos (2003). 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(Received: January 17, 2012; Accepted: October 30, 2012)

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Thalassas An International Journal of Marine Sciences

Number 28 (2) July 2012