DOCSLIB.ORG

Cephalopoda: Loliginidae)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Cephalopoda: Loliginidae) BULLETIN OF MARINE SCIENCE, 49(1-2): 309-311, 1991 PRELIMINARY STUDY ON THE FEEDING BY LOLIGO GAHI (CEPHALOPODA: LOLIGINIDAE) Angel Guerra, Bernardino G. Castro and Marion Nixon ABSTRACT The stomach contents of 13 specimens of Loligo gahi. captured off the Falkland Islands, were examined, The squids had all fed upon one species of crustacean belonging to the genus Euphausia. The weight of the stomach contents was between 4.5 and 8.0% of the total wet body weight. Several stomachs contained eyes from as many 96 to 244 individuals of this crustacean. The results shows that this species has a type and food intake similar to other loliginids and ommastrephids from temperate and boreal waters. Loligo gahi is fished in considerable quantity from these waters and its feeding habits indicate that it has an important influence on the krill, playing an important role in the trophic web of the ecosystem in these waters. The recent decline of fisheries in some areas has resulted in many Spanish trawlers fishing off the eastern coasts of the Falkland Islands. This has developed into a directed fishery for Loligo gahi. In 1986 some 90,000 tons were caught (Patterson, 1987). This squid is captured in depth of 160-300 m in waters of6- 10°C. The catches are frozen on board ship at -40°C, stored in 10 kg blocks in holds kept at - 20°C, and brought back to Vigo (NW Spain). The investigation of the diet of cephalopod will enable us to understand better the importance of these extremely efficient carnivores in the food web of the sea. As far as we know, this preliminary study is the first investigation of the feeding of this species in these waters. OBSERVATIONS AND CONCLUSIONS One hundred and twenty eight squids, captured in March 1987 off the Falkland Islands, were examined in Vigo. They were defrosting in tap water at room tem- perature; all were in good condition and all belonged to the same species, Loligo gahi d'Orbigny, 1835. The identification was made from the diagnosis given by Brakoniecki (1984). The animals ranged from 125 to 187 mm dorsal mantle length (DML). Males were all fully matures and females maturing (Lipinsky, 1979), placing them all within the size range of sexually mature (maturing) animals of this species (Hatfield et al., 1990). They showed very similar stomach fullness and stages of digestion of the prey. The digestive tract was removed from 13 specimens (7 males and 6 females) randomly taken from the total sample and the entire contents examined. The stomach in most cases was distended, but the oesophagus and intestine were empty. The contents of the stomach of each squid was weighed (Table 1). The food material present in the stomach of every specimen was found to belong to a single unidentified euphausiid species. Euphausiids, together with shrimps and prawns, form a considerable part of the diet of other loliginid squids (Nixon, 1987). At least some of the euphausiids eaten by Loligo gahi were mature and bearing eggs, and presumably of 45-50 mm total length, as the reconstructions made using entire cephalotorax and abdomens found have shown. The euphausiid remains in the stomachs of the squids were in fragments and showed some maceration. The fragments were all in the same stage of digestion. Adult euphausiids eaten 309 310 BULLETIN OF MARINE SCIENCE, VOL. 49, NO. 1-2. 1991 Table I. Thirteen spedmens of Loligo gahi are arranged in descending order of dorsal mantle length (DML), together with the total wet weight (W), the antero-posterior length of the buccal mass (LBM), the sex and the stage of maturation for each. The wet weight of the stomach contents (WSC) of each is given and shown as a percentage of its total body weight (W) LBM DML W(g) Sex Maturation WSC(g) % (WSC/WTB) (mm) 187 112.7 a mature 7.52 6.67 15.9 170 118.1 a mature 7.78 6.58 15.5 168 95.4 a mature 6.01 6.30 15.7 164 93.1 a mature 4.19 4.50 15.3 159 80.7 a mature 7.16 8.87 15.2 lSI 71.7 !i! maturing 4.83 6.16 15.0 144 79.9 !i! maturing 5.67 7.10 14.9 143 70.3 !i! maturing 3.76 5.35 14.9 142 71.6 !i! maturing 4.37 6.20 14.9 139 69.4 a maturing 6.10 8.79 14.8 131 58.7 !i! maturing 3.07 5.23 14.8 126 52.0 a mature 3.43 6.10 14.6 125 55.0 <;> maturing 4.83 8.78 14.5 would have been three times the antero-posterior length of the buccal mass (14.5- 15.9 mm, Table 1) of L. gaM. Thus it is certain that euphausiids are bitten into fragments short enough to enter the buccal cavity, and ofa diameter small enough to enter the oesophagus as in other loliginids (Bidder, 1950) and in Sepia (Guerra et al., 1988). The wet weight of the stomach contents ranged from 3.07-7.78 g, and formed from 4.5-8.87% of the total body weight (Table 1). Several stomachs contained many euphausiid single eyes, the number ranging from 192 to a maximum of 488, representing 96 to 244 individuals. This shows certainly that Loligo gahi is capable of capturing euphausiids in considerable numbers. An estimation of the time expended in the capture can be made on the basis of data of other teuthoids. Kier (1982) followed the capture of panaeid shrimps by L. pealei in the laboratory with a high speed camera. The tentacular strike was rapid, 15-35 msec, and the total time from the first sight of prey was 1.6-6.5 sec in all. In the sea a school of Illex illecebrosus was filmed whilst capturing and feeding on a surface swarm of Meganychtiphanes norvegica. These small euphausiids were caught with the swiftly ejected tentacles of the squid, an attack taking less than 2 sec (Nicol and O'Dor, 1985). Therefore, feeding on a swarm of euphausiids, L. gahi could capture 244 specimens taking between 6 and 26 min. It is not possible to assess the daily food consumption of Loligo gaM, but the stomach contents formed 4.50-8.97% of the total wet weight. This may be com- pared with the average daily intake of L. opalescens of 4-29%, with an average of 14.9%, under laboratory conditions in a temperature of 13°C or more (Yang et al., 1986). Also with the daily ratio of L. pealei (3.2-3.8% wet weight/day) estimated by Vinogradov and Noskov (1979), and with the daily ratio (9-10%) obtained by Macy (1980 in 1982) in the same species under laboratory conditions. This brief study shows that the feeding habits of Loligo gahi in the cold waters of the Falkland Islands are similar to those of other coastalloliginids living in temperate waters and ommastrephids (Illex illecebrosus) from boreal ones. Further detailed investigations of the species and size prey taken through the seasons and of the life cycle of L. gahi, together with the daily food intake and the rate of conversion of the squid are needed to determine the influence of this species on the trophic web of th~: ecosystem in which it lives. GUERRAETAL.:FEEDINGBY LOLlGO GAHI 311 ACKNOWLEDGMENTS We would like to thank M. T. Fernandez for her technical assistance. LITERATURE CITED Bidder, A. M. 1950. The digestive mechanism of the European squids Loligo vulgaris, Loligoforbesi, Alloteuthis media and Alloteuthis subulata Q. J. Micros. Sci. 91: 1-43. Brakoniecki, T. F. 1984. A full description of £Oligo sanpaulensis Brakoniecki, 1984 and redescription of Loligo gahi d'Orbigny 1835, two species of squid (Cephalopoda: Myopsida) from Southwest Atlantic. Bull. Mar. Sci. 34: 435-448. Guerra, A., M. Nixon and B. G. Castro. 1988. Initial stages of food ingestion by Sepia officinalis (Mollusca Cephalopoda). J. Zool. Lond. 214: 189-197. Hatfield, E. M. C., P. G. Rodhouse and J. Porebski. 1990. Demography and distribution of the Patagonian squid (£Oligo gahi d'Orbigny) during the austral winter. J. Const. Int. Explor. Mer 46: 306-312. Kier, W. M. 1982. The functional morphology of the musculature of squid (Loliginidae) arms and tentacles. J. Morph. 172: 179-192. Lipinski, M. 1979. Universal maturity scale for the commercially important squids. (Cephalopoda: Teuthoidea). ICNAF Res. Doc. 79/2/38, Ser. 5364:1-40. Macy, W. K. 1980. The ecology ofthe common squid Loligo pealei LeSueur, 1821 in Rhode Island waters. Ph.D. thesis, University of Rhode Island, Kingston. 236 pp. --. 1982. Feeding patterns of the long-finned squid, Loligo pealei in the New England waters. BioI. Bull. 162: 28-38. Nicol, S. and R. K. O'Dor. 1985. Predatory behaviour of squid (Illex illecebrosus) feeding on surface swarms ofeuphausiids. Can. J. Zool. 63: 15-17. Nixon, M. 1987. The diets of Cephalopods. In P. R. Boyle, ed. Cephalopod life cycles, Yol. II. Academic Press: 201-219. Patterson, K. 1987. Fishery events in the Falklands. New Scient. 114: 44-48. Yinogradov, Y. I. and A. S. Noskov. 1979. Feeding of short-finned squid, Illex illecebrosus, and long-finned squid, Loligo pea lei, off Nova Scotia and New England, 1974-75. ICNAF Sel. Pap. 5:31-36. Yang, W. T., R. F. Hixon, P. E. Turk, M. E. Krejci, W. H. Hulet and R. T. Hanlon. 1986. Growth, behavior, and sexual maturation ofthe market squid, Loligo opalescens, cultured through the life cycle. Fish. Bull.
Load more

Recommended publications
  • Longfin Squid 2018 Data Update
    Report to the Mid-Atlantic Fishery Management Council Regarding Fishery and Survey Data Updates, through 2017, for the Longfin Inshore Squid (Doryteuthis (Amerigo) pealeii) Stock by Lisa C. Hendrickson Population Dynamics Branch National Marine Fisheries Service Northeast Fisheries Science Center Woods Hole, MA 02543 April 9, 2018 1.0 Background This report contains updates of the landings and survey relative abundance and biomass indices of longfin inshore squid (Doryteuthis (Amerigo) pealeii) through 2017. The report also contains updates of the additional information requested by members of the Mid-Atlantic Fishery Management Council’s (MAFMC) Scientific and Statistical Committee (SSC) to aid them in recommending an Acceptable Biological Catch (ABC) for the D. pealeii stock in 2019. The additional information includes maps of the recent spatial distributions of the landings for the directed bottom trawl fishery and stratified mean body weights from the Northeast Fisheries Science Center’s (NEFSC) fall bottom trawl surveys. D. pealeii has a lifespan of less than one year (Macy and Brodziak 2001). The species inhabits the continental shelf and upper slope and ranges between southern Newfoundland and the Gulf of Venezuela, including the Gulf of Mexico and the Caribbean Sea (Jereb et al. 2010). The species is most abundant between Georges Bank and Cape Hatteras, North Carolina where a small-mesh bottom trawl fishery occurs throughout the year; offshore during late fall through early spring and inshore during the remainder of the year. The U.S. East Coast longfin squid population that inhabits the region between the Gulf of Maine and Cape Hatteras, NC (Northwest Atlantic Fisheries Organization (NAFO) Subareas 5 and 6, Figure 1) is managed as a single stock based on evidence from genetic studies (Arkhipkin et al.
    [Show full text]
  • In the Loliginid Squid Alloteuthis Subulata and Loligo Vulgaris
    The Journal of Experimental Biology 204, 2103–2118 (2001) 2103 Printed in Great Britain © The Company of Biologists Limited 2001 JEB3380 REFLECTIVE PROPERTIES OF IRIDOPHORES AND FLUORESCENT ‘EYESPOTS’ IN THE LOLIGINID SQUID ALLOTEUTHIS SUBULATA AND LOLIGO VULGARIS L. M. MÄTHGER1,2,* AND E. J. DENTON1 1The Marine Biological Association of the UK, Citadel Hill, Plymouth PL1 2PB, UK and 2Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK *e-mail: [email protected] Accepted 27 March 2001 Summary Observations were made of the reflective properties of parts of the spectrum and all reflections in other the iridophore stripes of the squid Alloteuthis subulata and wavebands, such as those in the red and near ultraviolet, Loligo vulgaris, and the likely functions of these stripes are will be weak. The functions of the iridophores reflecting red considered in terms of concealment and signalling. at normal incidence must be sought in their reflections of In both species, the mantle muscle is almost transparent. blue-green at oblique angles of incidence. These squid rely Stripes of iridophores run along the length of each side of for their camouflage mainly on their transparency, and the the mantle, some of which, when viewed at normal ventral iridophores and the red, green and blue reflective incidence in white light, reflect red, others green or blue. stripes must be used mainly for signalling. The reflectivities When viewed obliquely, the wavebands best reflected move of some of these stripes are relatively low, allowing a large towards the blue/ultraviolet end of the spectrum and fraction of the incident light to be transmitted into the their reflections are almost 100 % polarised.
    [Show full text]
  • Defensive Behaviors of Deep-Sea Squids: Ink Release, Body Patterning, and Arm Autotomy
    Defensive Behaviors of Deep-sea Squids: Ink Release, Body Patterning, and Arm Autotomy by Stephanie Lynn Bush A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Integrative Biology in the Graduate Division of the University of California, Berkeley Committee in Charge: Professor Roy L. Caldwell, Chair Professor David R. Lindberg Professor George K. Roderick Dr. Bruce H. Robison Fall, 2009 Defensive Behaviors of Deep-sea Squids: Ink Release, Body Patterning, and Arm Autotomy © 2009 by Stephanie Lynn Bush ABSTRACT Defensive Behaviors of Deep-sea Squids: Ink Release, Body Patterning, and Arm Autotomy by Stephanie Lynn Bush Doctor of Philosophy in Integrative Biology University of California, Berkeley Professor Roy L. Caldwell, Chair The deep sea is the largest habitat on Earth and holds the majority of its’ animal biomass. Due to the limitations of observing, capturing and studying these diverse and numerous organisms, little is known about them. The majority of deep-sea species are known only from net-caught specimens, therefore behavioral ecology and functional morphology were assumed. The advent of human operated vehicles (HOVs) and remotely operated vehicles (ROVs) have allowed scientists to make one-of-a-kind observations and test hypotheses about deep-sea organismal biology. Cephalopods are large, soft-bodied molluscs whose defenses center on crypsis. Individuals can rapidly change coloration (for background matching, mimicry, and disruptive coloration), skin texture, body postures, locomotion, and release ink to avoid recognition as prey or escape when camouflage fails. Squids, octopuses, and cuttlefishes rely on these visual defenses in shallow-water environments, but deep-sea cephalopods were thought to perform only a limited number of these behaviors because of their extremely low light surroundings.
    [Show full text]
  • Geographic and Temporal Patterns in Size and Maturity of the Longfin Inshore Squid (Loligo Pealeii) Off the Northeastern United States
    Geographic and temporal patterns in size and maturity of the longfin inshore squid (Loligo pealeii) off the northeastern United States Item Type article Authors Hatfield, Emma M.C.; Cadrin, Steven X. Download date 04/10/2021 18:55:59 Link to Item http://hdl.handle.net/1834/31057 200 Abstract–Analysis of 32 years of stan­ Geographic and temporal patterns dardized survey catches (1967–98) indi­ cated differential distribution patterns in size and maturity of the longfin inshore squid for the longfin inshore squid (Loligo pealeii) over the northwest Atlantic (Loligo pealeii) off the northeastern United States U.S. continental shelf, by geographic region, depth, season, and time of day. Emma M.C. Hatfield Catches were greatest in the Mid- Atlantic Bight, where there were sig­ Steven X. Cadrin nificantly greater catches in deep water Northeast Fisheries Science Center during winter and spring, and in National Marine Fisheries Service, NOAA shallow water during autumn. Body 166 Water Street size generally increased with depth Woods Hole, Massachusetts 02543 in all seasons. Large catches of juve­ Present address (for E.M.C. Hatfield): FRS Marine Laboratory niles in shallow waters off southern Victoria Road New England during autumn resulted Aberdeen AB11 9DB from inshore spawning observed during Scotland, United Kingdom late spring and summer; large propor­ E-mail address (for E. M. C. Hatfield): e.hatfi[email protected] tions of juveniles in the Mid-Atlantic Bight during spring suggest that sub­ stantial winter spawning also occurs. Few mature squid were caught in sur­ vey samples in any season; the major­ ity of these mature squid were cap­ tured south of Cape Hatteras during The longfin inshore squid, Loligo pea- mers, 1967; 1969; Serchuk and Rathjen, spring.
    [Show full text]
  • Divergence of Cryptic Species of Doryteuthis Plei Blainville
    Aberystwyth University Divergence of cryptic species of Doryteuthis plei Blainville, 1823 (Loliginidae, Cephalopoda) in the Western Atlantic Ocean is associated with the formation of the Caribbean Sea Sales, João Bráullio de L.; Rodrigues-Filho, Luis F. Da S.; Ferreira, Yrlene do S.; Carneiro, Jeferson; Asp, Nils E.; Shaw, Paul; Haimovici, Manuel; Markaida, Unai; Ready, Jonathan; Schneider, Horacio; Sampaio, Iracilda Published in: Molecular Phylogenetics and Evolution DOI: 10.1016/j.ympev.2016.09.014 Publication date: 2017 Citation for published version (APA): Sales, J. B. D. L., Rodrigues-Filho, L. F. D. S., Ferreira, Y. D. S., Carneiro, J., Asp, N. E., Shaw, P., Haimovici, M., Markaida, U., Ready, J., Schneider, H., & Sampaio, I. (2017). Divergence of cryptic species of Doryteuthis plei Blainville, 1823 (Loliginidae, Cephalopoda) in the Western Atlantic Ocean is associated with the formation of the Caribbean Sea. Molecular Phylogenetics and Evolution, 106(N/A), 44-54. https://doi.org/10.1016/j.ympev.2016.09.014 General rights Copyright and moral rights for the publications made accessible in the Aberystwyth Research Portal (the Institutional Repository) are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the Aberystwyth Research Portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the Aberystwyth Research Portal Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
    [Show full text]
  • Interannual Variation in Life-Cycle Characteristics of the Veined Squid (Loligo Forbesi). ICES CM 2004/CC:31
    Not to be cited without prior reference to the authors ICES CM 2004/CC:31 Interannual variation in life-cycle characteristics of the veined squid (Loligo forbesi) G.J. Pierce, A.F. Zuur, J.M. Smith, M.B. Santos, N. Bailey & P.R. Boyle The loliginid squid Loligo forbesi has a flexible life-cycle, involving variable size and age at maturity, presence of summer and winter breeding populations, and extended periods of breeding and recruitment. This paper reviews life history data collected since 1983 from the commercial fishery in Scottish (UK) waters and examines (a) the relationship between size and timing of maturation, (b) evidence for shifts in the relative abundance of the summer and winter breeding populations, and (c) the role of environmental signals in determining the timing of breeding. Evidence from fishery data suggests that, since the 1970s, the summer breeding population has declined while the winter breeding population now dominates and breeds later than was previously the case. Length-weight relationships and size at maturity showed significant inter-annual and seasonal variation during the period 1983-2001 and provide no evidence that there is currently a summer breeding population. Males are shown to decline in relative weight as they mature while females increase in relative weight. There is evidence that timing of breeding and size at maturity are related to environmental variation (winter NAO index). Key words: life history, time series, environmental factors G.J. Pierce, J.M. Smith, M.B. Santos, P.R. Boyle: University of Aberdeen, Tillydrone Avenue, Aberdeen AB24 2TZ, UK [tel: +44 1224 272866, fax: +44 1224 272396, e-mail: [email protected]].
    [Show full text]
  • Multiple Genetic Stocks of Longfin Squid Loligo Pealeii in the NW Atlantic: Stocks Segregate Inshore in Summer, but Aggregate Offshore in Winter
    MARINE ECOLOGY PROGRESS SERIES Vol. 310: 263–270, 2006 Published April 3 Mar Ecol Prog Ser Multiple genetic stocks of longfin squid Loligo pealeii in the NW Atlantic: stocks segregate inshore in summer, but aggregate offshore in winter K. C. Buresch, G. Gerlach, R. T. Hanlon* Marine Resources Center, Marine Biological Laboratory, Woods Hole, Massachusetts 02543, USA ABSTRACT: The longfin squid Loligo pealeii is distributed widely in the NW Atlantic and is the tar- get of a major fishery. A previous electrophoretic study of L. pealeii was unable to prove genetic dif- ferentiation, and the fishery has been managed as a single unit stock. We tested for population struc- ture using 5 microsatellite loci. In early summer (June), when the squids had migrated inshore to spawn, we distinguished 4 genetically distinct stocks between Delaware and Cape Cod (ca. 490 km); a 5th genetic stock occurred in Nova Scotia and a 6th in the northern Gulf of Mexico. One of the sum- mer inshore stocks did not show genetic differentiation from 2 of the winter offshore populations. We suggest that squids from summer locations overwinter in offshore canyons and that winter offshore fishing may affect multiple stocks of the inshore fishery. In spring, squids may segregate by genetic stock as they undertake their inshore migration, indicating an underlying mechanism of subpopula- tion recognition. KEY WORDS: Fisheries · Spawning migration · Microsatellites · Population structure · Population recognition · Null alleles Resale or republication not permitted without written consent of the publisher INTRODUCTION Most loliginid fisheries, including that for the longfin squid Loligo pealeii (Lesueur 1821), are managed as a The high dispersal capability of many marine organ- single unit stock (NEFSC 1996).
    [Show full text]
  • Lab 5: Phylum Mollusca
    Biology 18 Spring, 2008 Lab 5: Phylum Mollusca Objectives: Understand the taxonomic relationships and major features of mollusks Learn the external and internal anatomy of the clam and squid Understand the major advantages and limitations of the exoskeletons of mollusks in relation to the hydrostatic skeletons of worms and the endoskeletons of vertebrates, which you will examine later in the semester Textbook Reading: pp. 700-702, 1016, 1020 & 1021 (Figure 47.22), 943-944, 978-979, 1046 Introduction The phylum Mollusca consists of over 100,000 marine, freshwater, and terrestrial species. Most are familiar to you as food sources: oysters, clams, scallops, and yes, snails, squid and octopods. Some also serve as intermediate hosts for parasitic trematodes, and others (e.g., snails) can be major agricultural pests. Mollusks have many features in common with annelids and arthropods, such as bilateral symmetry, triploblasty, ventral nerve cords, and a coelom. Unlike annelids, mollusks (with one major exception) do not possess a closed circulatory system, but rather have an open circulatory system consisting of a heart and a few vessels that pump blood into coelomic cavities and sinuses (collectively termed the hemocoel). Other distinguishing features of mollusks are: z A large, muscular foot variously modified for locomotion, digging, attachment, and prey capture. z A mantle, a highly modified epidermis that covers and protects the soft body. In most species, the mantle also secretes a shell of calcium carbonate. z A visceral mass housing the internal organs. z A mantle cavity, the space between the mantle and viscera. Gills, when present, are suspended within this cavity.
    [Show full text]
  • Geographic Drivers of Diversification in Loliginid Squids with an Emphasis on the Western Atlantic Species
    bioRxiv preprint doi: https://doi.org/10.1101/2020.07.20.211896; this version posted July 21, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 1 Original Article Geographic drivers of diversification in loliginid squids with an emphasis on the western Atlantic species Gabrielle Genty1*, Carlos J Pardo-De la Hoz1,2*, Paola Montoya1,3, Elena A. Ritschard1,4* 1Departamento de Ciencias Biológicas, Universidad de los Andes, Bogotá D.C, Colombia. 2Department of Biology, Duke University, Durham, North Carolina, 27708, United States of America 3Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Bogotá, D.C., Colombia 4Department of Neuroscience and Developmental Biology, University of Vienna, Austria * These authors contributed equally to this work. Correspondence author: Gabrielle Genty, [email protected] Acknowledgements We would like to thank Daniel Cadena and Andrew J. Crawford for their suggestions and guidance during the early stages of this investigation. bioRxiv preprint doi: https://doi.org/10.1101/2020.07.20.211896; this version posted July 21, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 2 ABSTRACT Aim: Identifying the mechanisms driving divergence in marine organisms is challenging as opportunities for allopatric isolation are less conspicuous than in terrestrial ecosystems.
    [Show full text]
  • Cephalopod Species Living In
    BASTERIA, 69: 91-119, 2005 Seasonal distributionof cephalopod species living in the central and southern North Sea A. de Heij Celebesstraat 5, NL 6707 ED Wageningen,The Netherlands;[email protected] & R.P. Baayen Gijsbrecht van Amstellaan 18, NL 3703 BD Zeist, The Netherlands; [email protected] During the International Bottom Trawl Surveys and International Beam Trawl Surveys from 1996 in to 2003, ten cephalopodspecies were encountered the central and southern North Sea in six families: Loliginidae(Alloteuthis subulata, Loligo forbesi, Loligo vulgaris), Sepiolidae ( Sepiola atlantica, Rossia macrosoma, Sepietta oweniana), Sepiidae (Sepia officinalis), Ommastrephidae (Todaropsis eblanae), Onychoteuthidae (Onychoteuthis banksii), and Octopodidae (Eledone cir- from in in rhosa). Apart A. subulata, noneof the species lived the investigated area large num- is bers. In general, the central and southern North Sea not a favourable habitat for cephalopods due to the shallowness ofthe water. The occurrence of individual species is further restricted by water temperatureor salinity requirements, as shown by their seasonal migrationpatterns. These of the and influx of from outside. parameters depend on sea depth, time year, water waters in Inside the central and southern North Sea, deep are relatively cool summer but rela- in tively warm winter, while the shallow coastal waters of Belgium and The Netherlands are warm in summer and cold in winter. This explains the seasonal migration ofAlloteuthis subula- It north- ta, a species indigenous to the North Sea that prefers relatively warm waters. migrates westwards before winter and southeastwards in late spring. A similar migration pattern exists for the two other species in the Loliginidae, Loligo forbesi and L.
    [Show full text]
  • First Record of an Egg Mass of Loligo Forbesi (Cephalopoda: Loliginidae) in the Ligurian Sea, with Notes About Egg Laying Patterns in Southern Populations
    Boll. Malacol., 45: 27-33 (suppl. 2009) First record of an egg mass of Loligo forbesi (Cephalopoda: Loliginidae) in the Ligurian Sea, with notes about egg laying patterns in southern populations Lidia Orsi Relini (), Alessandro Mannini, Luca Lanteri & Eugenio Beccornia DIP.TE.RIS, Laboratori Abstract di Biologia Marina During the trawl survey MEDITS 2005, an egg mass of Loligo forbesi was collected in the western Ligurian ed Ecologia Animale, Sea, on a muddy bottom at about 600 m of depth. This record, the first in the study area, is discussed taking Università di Genova into account general information about spawning in L. forbesi Mediterranean and Macaronesian popula- Corso Europa 26, 16132 Genova, Italy, tions. The occurrence of different reproductive patterns in Loligo species are underlined and in L. forbesi the [email protected] existence of egg strands heavier and lighter than the sea water is considered indicative of a spawning strat- egy evolving with time and age of the female. Riassunto Si riporta il primo ritrovamento di uova di L. forbesi su fondi fangosi batiali del Mar Ligure occidentale, a circa 600 m di profondità. Per commentare questo reperto ed inquadrarlo nella biologia della specie, si rias- sumono le informazioni sulla riproduzione reperibili nella letteratura relativa al Mediterraneo e all’Atlantico adiacente. Queste riguardano: 1) la presenza di zone di deposizione in prossimità del limite piattaforma/ scarpata, che fu accertata circa un secolo fa dai ricercatori della Stazione Zoologica di Napoli; 2) l’associazio- ne delle capsule ovigere a celenterati coloniali che risulta dalle stesse ricerche; 3) lo sviluppo embrionale, con simili dimensioni alla schiusa in materiale del Mediterraneo e delle Azzorre; 4) osservazioni sul comporta- mento condotte alle Azzorre sia su individui marcati, sia su individui in cattività: di questi ultimi è stato os- servato l’accoppiamento e la deposizione delle uova; 5) un recente ritrovamento di uova deposte a circa 730 m di profondità nell’Egeo.
    [Show full text]
  • Reproductive Cycle of Loligo Sanpa Ulensis (Cephalopoda: Loliginidae) in the Cabo Frio Region, Brazil
    MARINE ECOLOGY PROGRESS SERIES Published November 4 Mar. Ecol. Prog. Ser. Reproductive cycle of Loligo sanpa ulensis (Cephalopoda: Loliginidae) in the Cabo Frio region, Brazil P. A. S. Costa, F. C. Fernandes Instituto de Estudos do Mar Alte Paulo Moreira (IEAPM), Rua Kioto. 253 Arraial do Cabo. 28930-000 Rio de Janeiro, Brazil ABSTRACT. Gonadal index and maturity stages of the Brazilian squid Loljgo sanpaulensjs were analysed on a monthly basis. Squid were caught in coastal waters off the Cabo Frio region, Brazil, between 1987 and 1988 at depths rang~ngfrom 30 to 60 m using an otter trawl with 10 m footrope and 45 mm cod-end mesh size. Field data analysis showed that development of the nidamental gland and testis was closely related (r > 0.9) to body size and maturity stage in the population. Mature indiv~duals are recruited into the population twice a year. Size at first maturity was estimated to be 50 to 55 mm mantle length (ML) for males and 55 to 60 mm ML for females. Indirect evidence suggests that the final phases of the maturity process in females occur abruptly at some point after that size, and that recruit- ment of juveniles follows spawning and subsequent mortality or emigration of adults from the sampling area. Spawning is likely to take place in late summer and late winter INTRODUCTION Mexico Loligo pealei spawns throughout the year (Hixon 1980). Sepioteuthis sepioidea in the western Basic information on maturation and size at maturity tropical Atlantic and S. lessoniana in the western is fragmentary for many cephalopods, especially for Pacific also spawn year-round (Choe 1966, LaRoe those living in non-seasonal environments.
    [Show full text]