DOCSLIB.ORG

(Myoxocephalus Scorpius) in Reduced Salinity

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
(Myoxocephalus Scorpius) in Reduced Salinity Journal of Comparative Physiology B (2021) 191:301–311 https://doi.org/10.1007/s00360-020-01336-8 ORIGINAL PAPER Energetic savings and cardiovascular dynamics of a marine euryhaline fsh (Myoxocephalus scorpius) in reduced salinity Erika Sundell1 · Daniel Morgenroth1 · Andreas Ekström1 · Jeroen Brijs2 · Michael Axelsson1 · Albin Gräns3 · Erik Sandblom1 Received: 12 October 2020 / Revised: 18 November 2020 / Accepted: 12 December 2020 / Published online: 4 February 2021 © The Author(s) 2021 Abstract Few studies have addressed how reduced water salinity afects cardiovascular and metabolic function in marine euryhaline fshes, despite its relevance for predicting impacts of natural salinity variations and ongoing climate change on marine fsh populations. Here, shorthorn sculpin (Myoxocephalus scorpius) were subjected to diferent durations of reduced water salinity from 33 to 15 ppt. Routine metabolic rate decreased after short-term acclimation (4–9 days) to 15 ppt, which corresponded with similar reductions in cardiac output. Likewise, standard metabolic rate decreased after acute transition (3 h) from 33 to 15 ppt, suggesting a reduced energetic cost of osmoregulation at 15 ppt. Interestingly, gut blood fow remained unchanged across salinities, which contrasts with previous fndings in freshwater euryhaline teleosts (e.g., rainbow trout) exposed to diferent salinities. Although plasma osmolality, [Na+], [Cl−] and [Ca2+] decreased in 15 ppt, there were no signs of cellular osmotic stress as plasma [K+], [hemoglobin] and hematocrit remained unchanged. Taken together, our data suggest that shorthorn sculpin are relatively weak plasma osmoregulators that apply a strategy whereby epithelial ion transport mecha- nisms are partially maintained across salinities, while plasma composition is allowed to fuctuate within certain ranges. This may have energetic benefts in environments where salinity naturally fuctuates, and could provide shorthorn sculpin with competitive advantages if salinity fuctuations intensify with climate change in the future. Keywords Cardiovascular · Metabolic rate · Marine · Euryhaline · Salinity variability Introduction predicted to become more extreme in the future due to cli- mate change resulting in, e.g., longer periods of exacerbated Many coastal marine environments are characterized by drought and evaporation, increased freshwater run-of due to large fuctuations in water salinity, which challenges the altered precipitation patterns, and a more intensifed mixing osmotic homeostasis of animals inhabiting these environ- of water layers due to changing wind conditions (Durack ments. Moreover, alterations in environmental salinity are et al. 2012; IPCC 2019; Zika et al. 2018). This will be par- ticularly pronounced in shallow bays and estuaries, as these areas already experience pronounced variations in salinity Communicated by B. Pelster. (Bindof et al. in press; Held and Soden 2006; IPCC 2013). Supplementary Information The online version contains Since environmental salinity impacts a wide range of supplementary material available at https ://doi.org/10.1007/s0036 biological processes and physiological functions, abrupt 0-020-01336 -8. changes in salinity require aquatic animals such as marine * Erika Sundell fshes to either migrate to more favorable conditions, or to [email protected] acclimate their physiology to maintain homeostasis (Kultz 2015). Consequently, salinity changes can lead to local alter- 1 Department of Biological and Environmental Sciences, ations in species distribution, as well as changes in the struc- University of Gothenburg, Gothenburg, Sweden ture of ecosystems (Smyth and Elliot 2016). Nonetheless, to 2 Institute of Marine Biology, University of Hawai’i at Mānoa, assess how coastal marine fshes adjust to transient decreases Honolulu, USA in salinity, and to make predictions about future ecological 3 Department of Animal Environment and Health, Swedish implications of increased salinity variations, there is a need University of Agricultural Sciences, Gothenburg, Sweden Vol.:(0123456789)1 3 302 Journal of Comparative Physiology B (2021) 191:301–311 to understand the energetic consequences and underlying water (i.e., freshwater). Even so, empirical data are confict- physiological responses governing salinity tolerance of fsh. ing concerning the correlation between the energetic costs of In this study, we used the shorthorn sculpin (Myoxocephalus osmoregulation and environmental salinity (Ern et al. 2014). scorpius) as a model to evaluate the efect of reduced salinity From a metabolic point of view, this knowledge gap com- on cardiorespiratory function in a marine euryhaline teleost. plicates predictions about the success of fshes in a future The shorthorn sculpin is a relatively stationary demersal with more intense salinity fuctuations (Kultz 2015; Morgan species that inhabits a variety of coastal habitats, including and Iwama 1998). estuaries (Bone and Moore 2008; Coad and Reist 2004), The cardiovascular system drives tissue convection of and is known to tolerate salinities down to at least ~ 11.5 ppt water, ions, respiratory gases, nutrients, waste products and (Foster 1969; Oikari 1978a, b). The population of shorthorn hormones (Sandblom and Gräns 2017). Changes in cardio- sculpin examined here were collected from an area on the vascular physiology are, therefore, crucial for coping with Swedish west coast where the salinity regularly fuctuates changing salinities. In rainbow trout, both acute exposure between full-strength seawater of ~ 33 ppt and down to ~ 20 and chronic acclimation to increased salinity coincides with ppt within a few hours (Fig. 1). a suite of marked cardiovascular adjustments. Importantly, a Previous studies on other euryhaline fshes such as rain- twofold increase in gut blood fow occurs in seawater (Brijs bow trout (Oncorhynchus mykiss) have shown that a trans- et al. 2015, 2016a), which likely serves to increase the con- fer from freshwater to seawater involves an upregulation of vective transport of absorbed ions and water away from the active intestinal ion transport mechanisms and increased intestine to their respective sites for utilization or excretion drinking rates to sustain the elevated demand for intesti- (Brijs et al. 2015, 2016a; Farrell et al. 2009). The elevated nal water absorption, which is necessary to compensate for gut blood fow is likely explained by a reduced gut vascular osmotic water loss to the hypersaline environment (Brijs resistance (Sundell et al. 2018), and a sustained increase in et al. 2015; Fuentes et al. 1997; Grosell 2013). This pro- cardiac output and stroke volume (Brijs et al. 2015, 2016a; cess involves increased intestinal epithelial Na+/K+-ATPase Sundell et al. 2018). These responses are associated with a activity that creates a trans-epithelial Na + gradient driving plastic restructuring of the heart, where the proportion of osmotic uptake of water into the blood (Grosell 2010; Whit- compact myocardium of the ventricle increases (Brijs et al. tamore 2012). Increased trans-epithelial transport of ions 2016b). Thus, while the cardiovascular responses of eury- has been suggested to be refected in an elevated standard haline fshes to increased salinity has been extensively char- metabolic rate (SMR), which is typically defned as the acterized (Brijs et al. 2015, 2016a, b; Maxime et al. 1991; minimal aerobic energy required by an animal to maintain Morgenroth et al. 2019; Olson and Hoagland 2008; Sundell basal homeostatic processes (Chabot et al. 2016; Ern et al. et al. 2018), virtually nothing is known about the cardiovas- 2014). Thus, the magnitude of the overall energy expendi- cular mechanisms governing tolerance to reduced salinity ture associated with osmoregulation should depend on the in marine teleosts. Indeed, knowledge about the combined osmotic gradient between the fsh and its environment, and cardiovascular and metabolic responses would shed light thus theoretically, osmoregulation in water iso-osmotic to onto how marine fshes cope with transient reductions in the blood plasma (i.e., ~ 10ppt) should be less energetically salinity, as well as potential physiological benefts and trade- costly than both hyper- (i.e., seawater) and hypo-osmotic ofs when environmental salinity fuctuates. Animal collection 35 25 a b 20 Te mperature ) 30 ppt 15 ( 25 10 ( ° Salinity 20 C) 5 150 0 Oct-17 Jan-18 Apr-18Jul-18Oct-18Jan-19 Fig. 1 Geographical location and environmental characteristics of ity (solid pink line) and temperature (hatched gray line) of the water the Gullmarsforden area where shorthorn sculpin (Myoxocephalus body within Gullmarsforden measured at 6 m depth between October scorpius) were collected. a The specifc area from which shorthorn 2017 and January 2019 near to where shorthorn sculpin were caught sculpin were caught within the Gullmarsforden (hatched ellipse) (the period for animal collection is indicated by the horizontal bar in on the Swedish west coast (square within inset map). b Mean salin- panel b). Logged data were unavailable during the two blank periods 1 3 Journal of Comparative Physiology B (2021) 191:301–311 303 In the present study, we measured routine metabolic rate Table 1 Morphological characteristics of Shorthorn sculpin (Myoxo- (RMR) and cardiovascular responses (i.e., cardiac output, cephalus scorpius) heart rate, stroke volume and gut blood fow) in shorthorn Experiment 1 Experiment 2 sculpin surgically instrumented with blood fow probes in full- 33 ppt 15 ppt 33 ppt 15 ppt strength
Load more

Recommended publications
  • Appendix 13.2 Marine Ecology and Biodiversity Baseline Conditions
    THE LONDON RESORT PRELIMINARY ENVIRONMENTAL INFORMATION REPORT Appendix 13.2 Marine Ecology and Biodiversity Baseline Conditions WATER QUALITY 13.2.1. The principal water quality data sources that have been used to inform this study are: • Environment Agency (EA) WFD classification status and reporting (e.g. EA 2015); and • EA long-term water quality monitoring data for the tidal Thames. Environment Agency WFD Classification Status 13.2.2. The tidal River Thames is divided into three transitional water bodies as part of the Thames River Basin Management Plan (EA 2015) (Thames Upper [ID GB530603911403], Thames Middle [ID GB53060391140] and Thames Lower [ID GB530603911401]. Each of these waterbodies are classified as heavily modified waterbodies (HMWBs). The most recent EA assessment carried out in 2016, confirms that all three of these water bodies are classified as being at Moderate ecological potential (EA 2018). 13.2.3. The Thames Estuary at the London Resort Project Site is located within the Thames Middle Transitional water body, which is a heavily modified water body on account of the following designated uses (Cycle 2 2015-2021): • Coastal protection; • Flood protection; and • Navigation. 13.2.4. The downstream extent of the Thames Middle transitional water body is located approximately 12 km downstream of the Kent Project Site and 8 km downstream of the Essex Project Site near Lower Hope Point. Downstream of this location is the Thames Lower water body which extends to the outer Thames Estuary. 13.2.5. A summary of the current Thames Middle water body WFD status is presented in Table A13.2.1, together with those supporting elements that do not currently meet at least Good status and their associated objectives.
    [Show full text]
  • Trophic Niche Partitioning of Littoral Fish Species from the Rocky Intertidal Of
    Helgol Mar Res (2015) 69:385–399 DOI 10.1007/s10152-015-0444-5 ORIGINAL ARTICLE Trophic niche partitioning of littoral fish species from the rocky intertidal of Helgoland, Germany 1,2 3 4 1 N. N. Hielscher • A. M. Malzahn • R. Diekmann • N. Aberle Received: 30 January 2015 / Revised: 1 October 2015 / Accepted: 15 October 2015 / Published online: 27 October 2015 Ó Springer-Verlag Berlin Heidelberg and AWI 2015 Abstract During a 3-year field study, interspecific and the littoral zones of Helgoland and on complex benthic interannual differences in the trophic ecology of littoral fish food webs in general. species were investigated in the rocky intertidal of Hel- goland island (North Sea). We investigated trophic niche Keywords Fatty acids Á Stable isotopes Á Ctenolabrus partitioning of common coexisting littoral fish species rupestris Á Pomatoschistus minutus Á Pomatoschistus based on a multi-tracer approach using stable isotope and pictus Á Myoxocephalus scorpius Á Taurulus bubalis Á fatty acids in order to show differences and similarities in Trophic ecology Á Feeding ecology resource use and feeding modes. The results of the dual- tracer approach showed clear trophic niche partitioning of the five target fish species, the goldsinny wrasse Cteno- Introduction labrus rupestris, the sand goby Pomatoschistus minutus, the painted goby Pomatoschistus pictus, the short-spined Understanding the trophic interactions in complex and sea scorpion Myoxocephalus scorpius and the long-spined diverse marine ecosystems is a significant challenge. In sea scorpion Taurulus bubalis. Both stable isotopes and order to obtain a profound knowledge on complex fatty acids showed distinct differences in the trophic ecosystems, it is important to address trophodynamic ecology of the studied fish species.
    [Show full text]
  • Biodiversity of Arctic Marine Fishes: Taxonomy and Zoogeography
    Mar Biodiv DOI 10.1007/s12526-010-0070-z ARCTIC OCEAN DIVERSITY SYNTHESIS Biodiversity of arctic marine fishes: taxonomy and zoogeography Catherine W. Mecklenburg & Peter Rask Møller & Dirk Steinke Received: 3 June 2010 /Revised: 23 September 2010 /Accepted: 1 November 2010 # Senckenberg, Gesellschaft für Naturforschung and Springer 2010 Abstract Taxonomic and distributional information on each Six families in Cottoidei with 72 species and five in fish species found in arctic marine waters is reviewed, and a Zoarcoidei with 55 species account for more than half list of families and species with commentary on distributional (52.5%) the species. This study produced CO1 sequences for records is presented. The list incorporates results from 106 of the 242 species. Sequence variability in the barcode examination of museum collections of arctic marine fishes region permits discrimination of all species. The average dating back to the 1830s. It also incorporates results from sequence variation within species was 0.3% (range 0–3.5%), DNA barcoding, used to complement morphological charac- while the average genetic distance between congeners was ters in evaluating problematic taxa and to assist in identifica- 4.7% (range 3.7–13.3%). The CO1 sequences support tion of specimens collected in recent expeditions. Barcoding taxonomic separation of some species, such as Osmerus results are depicted in a neighbor-joining tree of 880 CO1 dentex and O. mordax and Liparis bathyarcticus and L. (cytochrome c oxidase 1 gene) sequences distributed among gibbus; and synonymy of others, like Myoxocephalus 165 species from the arctic region and adjacent waters, and verrucosus in M. scorpius and Gymnelus knipowitschi in discussed in the family reviews.
    [Show full text]
  • APPENDIX 1 Classified List of Fishes Mentioned in the Text, with Scientific and Common Names
    APPENDIX 1 Classified list of fishes mentioned in the text, with scientific and common names. ___________________________________________________________ Scientific names and classification are from Nelson (1994). Families are listed in the same order as in Nelson (1994), with species names following in alphabetical order. The common names of British fishes mostly follow Wheeler (1978). Common names of foreign fishes are taken from Froese & Pauly (2002). Species in square brackets are referred to in the text but are not found in British waters. Fishes restricted to fresh water are shown in bold type. Fishes ranging from fresh water through brackish water to the sea are underlined; this category includes diadromous fishes that regularly migrate between marine and freshwater environments, spawning either in the sea (catadromous fishes) or in fresh water (anadromous fishes). Not indicated are marine or freshwater fishes that occasionally venture into brackish water. Superclass Agnatha (jawless fishes) Class Myxini (hagfishes)1 Order Myxiniformes Family Myxinidae Myxine glutinosa, hagfish Class Cephalaspidomorphi (lampreys)1 Order Petromyzontiformes Family Petromyzontidae [Ichthyomyzon bdellium, Ohio lamprey] Lampetra fluviatilis, lampern, river lamprey Lampetra planeri, brook lamprey [Lampetra tridentata, Pacific lamprey] Lethenteron camtschaticum, Arctic lamprey] [Lethenteron zanandreai, Po brook lamprey] Petromyzon marinus, lamprey Superclass Gnathostomata (fishes with jaws) Grade Chondrichthiomorphi Class Chondrichthyes (cartilaginous
    [Show full text]
  • Kane-Higham-2012.Pdf
    G Model ZOOL-25301; No. of Pages 10 ARTICLE IN PRESS Zoology xxx (2012) xxx–xxx Contents lists available at SciVerse ScienceDirect Zoology journa l homepage: www.elsevier.com/locate/zool Life in the flow lane: differences in pectoral fin morphology suggest transitions in station-holding demand across species of marine sculpin ∗ Emily A. Kane , Timothy E. Higham University of California, Riverside, Department of Biology, 900 University Ave., Riverside, CA 92521, USA a r t i c l e i n f o a b s t r a c t Article history: Aquatic organisms exposed to high flow regimes typically exhibit adaptations to decrease overall drag Received 28 September 2011 and increase friction with the substrate. However, these adaptations have not yet been examined on a Received in revised form 27 February 2012 structural level. Sculpins (Scorpaeniformes: Cottoidea) have regionalized pectoral fins that are modified Accepted 7 March 2012 for increasing friction with the substrate, and morphological specialization varies across species. We examined body and pectoral fin morphology of 9 species to determine patterns of body and pectoral Keywords: fin specialization. Intact specimens and pectoral fins were measured, and multivariate techniques deter- Benthic fishes mined the differences among species. Cluster analysis identified 4 groups that likely represent differences Scorpaeniformes in station-holding demand, and this was supported by a discriminant function analysis. Primarily, the Flow regime high-demand group had increased peduncle depth (specialization for acceleration) and larger pectoral Functional regionalization Station-holding fins with less webbed ventral rays (specialization for mechanical gripping) compared to other groups; secondarily, the high-demand group had a greater aspect ratio and a reduced number of pectoral fin rays (specialization for lift generation) than other groups.
    [Show full text]
  • Baseline Respiration and Spontaneous Activity of Sluggish Marine Tropical Fish of the Family Scorpaenidae
    MARINE ECOLOGY PROGRESS SERIES Vol. 219: 229–239, 2001 Published September 10 Mar Ecol Prog Ser Baseline respiration and spontaneous activity of sluggish marine tropical fish of the family Scorpaenidae Christopher Zimmermann1, 2,*, Andreas Kunzmann1, 3 1Institut für Polarökologie der Universität Kiel, Wischhofstr. 1–3, Geb. 12, 24148 Kiel, Germany 2Institut für Seefischerei, Bundesforschungsanstalt für Fischerei, Palmaille 9, 22767 Hamburg, Germany 3Zentrum für Marine Tropenökologie, Universität Bremen, Fahrenheitstr. 6, 28359 Bremen, Germany ABSTRACT: Baseline respiration and spontaneous activity were determined simultaneously for 6 specimens of tropical scorpionfishes, belonging to 2 different genera: Scorpaenopsis oxycephalus and S. diabolus (false stonefish) and Parascorpaena sp. and P. aurita. The experiments were conducted in an intermittent-flow respirometer at 24°C, at ambient light regime (12 h dark: 12 h light) and salinity (S = 32). Permanent measurements of fish activity by an infrared video system (number of move- ments) and oxygen consumption were coupled allowing the calculation of a standard oxygen con- sumption (SOC) rate. The experimental set-up allowed quantification of spontaneous activity. Rela- –1 –1 tive SOC values varied between 32.3 mg O2 h kg wet mass (wm) for a large S. oxycephalus (82 g –1 –1 WM) and 68.9 mg O2 h kg WM for the smallest investigated specimen, a P. aurita (16 g WM). The latter also showed the highest spontaneous activity rate (mean 98 movements h–1; max.: 870 h–1), while the values for the most sluggish individual did not exceed 24.6 h–1 (mean) and 480 h–1 (max.), –1 respectively. Absolute SOC for a standard mass of 50 g was calculated to be 2.0 mg O2 h , using a –1 0.527 wet mass versus oxygen consumption relationship of SOC (mg O2 h ) = 0.26 × WM(g) .
    [Show full text]
  • Resource Partitioning Among Myoxocephalus Sculpins, and Their Predator–Prey Relationships with Chionoecetes Crabs in the Eastern Bering Sea
    Vol. 464: 221–235, 2012 MARINE ECOLOGY PROGRESS SERIES Published September 19 doi: 10.3354/meps09878 Mar Ecol Prog Ser Resource partitioning among Myoxocephalus sculpins, and their predator–prey relationships with Chionoecetes crabs in the eastern Bering Sea Todd T. TenBrink*, Troy W. Buckley Resource Ecology and Fisheries Management Division, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, 7600 Sand Point Way NE, Seattle, Washington 98115, USA ABSTRACT: Interspecific and intraspecific variation in the distributions and diets of congeneric sculpins, Myoxocephalus jaok, M. polyacanthocephalus, and M. scorpius, were described from data collected during summer trawl surveys of the eastern Bering Sea (EBS) continental shelf between 2000 and 2010 by the Alaska Fisheries Science Center (AFSC). Generalized additive models (GAMs) of abundance (count) and presence-absence data were applied separately for each species to examine the influence of selected factors (depth, bottom temperature, substrate type and location) on distribution and abundance. The final models indicated strong predictive relationships, suggesting habitat partitioning between species. Ontogenetic distributions were observed as larger individuals of each species tended to be associated with deeper depths and lower latitudes. Analysis of stomach contents indicated that these species consume a wide variety of prey and that the diet composition also shifted ontogenetically. Multivariate analyses of the mean percent weight (%W) of 23 diet categories indicated that the diets differed among and within species. The diet of M. jaok consisted primarily of mysids, shrimps, and flatfish, with larger sculpins feeding on a greater amount of flatfish prey and less benthic infauna. Both M. polyacan- thocephalus and M. scorpius fed considerably on commercially important Chionoecetes crabs, particularly C.
    [Show full text]
  • A Cyprinid Fish
    DFO - Library / MPO - Bibliotheque 01005886 c.i FISHERIES RESEARCH BOARD OF CANADA Biological Station, Nanaimo, B.C. Circular No. 65 RUSSIAN-ENGLISH GLOSSARY OF NAMES OF AQUATIC ORGANISMS AND OTHER BIOLOGICAL AND RELATED TERMS Compiled by W. E. Ricker Fisheries Research Board of Canada Nanaimo, B.C. August, 1962 FISHERIES RESEARCH BOARD OF CANADA Biological Station, Nanaimo, B0C. Circular No. 65 9^ RUSSIAN-ENGLISH GLOSSARY OF NAMES OF AQUATIC ORGANISMS AND OTHER BIOLOGICAL AND RELATED TERMS ^5, Compiled by W. E. Ricker Fisheries Research Board of Canada Nanaimo, B.C. August, 1962 FOREWORD This short Russian-English glossary is meant to be of assistance in translating scientific articles in the fields of aquatic biology and the study of fishes and fisheries. j^ Definitions have been obtained from a variety of sources. For the names of fishes, the text volume of "Commercial Fishes of the USSR" provided English equivalents of many Russian names. Others were found in Berg's "Freshwater Fishes", and in works by Nikolsky (1954), Galkin (1958), Borisov and Ovsiannikov (1958), Martinsen (1959), and others. The kinds of fishes most emphasized are the larger species, especially those which are of importance as food fishes in the USSR, hence likely to be encountered in routine translating. However, names of a number of important commercial species in other parts of the world have been taken from Martinsen's list. For species for which no recognized English name was discovered, I have usually given either a transliteration or a translation of the Russian name; these are put in quotation marks to distinguish them from recognized English names.
    [Show full text]
  • Disease of Aquatic Organisms 101:51
    Vol. 101: 51–60, 2012 DISEASES OF AQUATIC ORGANISMS Published October 10 doi: 10.3354/dao02508 Dis Aquat Org Experimental infection of yellow stingrays Urobatis jamaicensis with the marine leech Branchellion torpedinis David P. Marancik1,*, Alistair D. Dove2, Alvin C. Camus1 1Department of Pathology, The University of Georgia College of Veterinary Medicine, Athens, Georgia 30602, USA 2Department of Veterinary Services and Conservation Medicine, Georgia Aquarium Inc., Atlanta, Georgia 30313, USA ABSTRACT: Infestations of elasmobranchs by the marine leech Branchellion torpedinis can be problematic in aquaria and negatively affect host health. To better characterize the extent and pathogenesis of disease, 12 yellow stingrays Urobatis jamaicensis were infected with 1 or 3 leeches for 14 d. Leeches were associated with anorexia, extensive cutaneous ulceration, de - creased host packed cell volume (PCV) and serum total solids (TS), and mortality in 3 rays. Aver- age decrease in host PCV positively correlated with ulcer size and parasite:host ratio. Average decrease in host serum TS positively correlated with parasite:host ratio. Blood chemistry and total white blood cell counts revealed no significant trends. Additional necropsy findings included gill and splenic pallor, pericardial edema, perirenal edema, and decreased hepatocellular lipid deposits. Microscopic evaluation of leeches demonstrated host erythrocytes and proteinaceous fluid within parasite intestines, confirming active blood feeding. Results indicate B. torpedinis has the potential to cause significant disease in elasmobranchs, including death in as few as 5 d, and identifies ulcer size and parasite:host ratio as risk factors for disease. Elucidation of this host-par- asite interaction helps characterize host response to parasites and facilitate care of parasitized elasmobranchs in aquarium and wild settings.
    [Show full text]
  • Diets of Shags Phalacrocorax Aristotelis and Cormorants P
    MARINE ECOLOGY PROGRESS SERIES Vol. 66: 205-218. 1990 Published September 6 Mar. Ecol. Prog. Ser. Diets of shags Phalacrocorax aristotelis and cormorants P. carbo in Norway and possible implications for gadoid stock recruitment ' Norwegian Institute for Nature Research, c/o Tromse Museum, University of Tromsa, N-9000 Tromse. Norway Norwegian Institute for Nature Research, Tungasletta 2. N-7004 Trondheim, Norway Depts of Psychology and Biology, and Ocean Sciences Centre, Memorial University of Newfoundland. St. John's. Newfoundland. Canada A1B 3x9 ABSTRACT: The diets of shags and cormorants were studied in Norway through analyses of regurgi- tated pellets. Although this method has many limitations, indications were that both species rely heavily on small gadoids (Gadidae) and sand eels (Ammodytidae) for food throughout their range, but also eat other fish species when available. There was considerable dietary overlap between species, despite a tendency for cormorants to eat larger fish and more benthic items than shags. Predation by shags and cormorants could be a factor limiting the recruitment of cod and saithe into what are now severely reduced, but commercially important stocks in the Norwegian and Barents Seas. INTRODUCTION scientific study. Although commercial species have repeatedly been found in the diets of shag and cormor- There is an increasing awareness of the roles of ants in e.g. Britain, Canada and Australia, their con- seabirds in marine ecosystems (e.g. Croxall et al. 1985, sumption is now usually judged to be inconsequential Schneider et al. 1986, Croxall 1987) and recent to fisheries (Lumsden & Haddow 1946, Rae 1969, West estimates in areas of major seabird concentrations are et al.
    [Show full text]
  • The Structure of Parasite Component Communities in Brackish Water fishes of the Northeastern Baltic Sea
    471 The structure of parasite component communities in brackish water fishes of the northeastern Baltic Sea E.T.VALTONEN"*, K.PULKKINEN", R.POULIN# and M.JULKUNEN" " Department of Biological and Environmental Science, University of JyvaW skylaW , 40100 JyvaW skylaW , Finland # Department of Zoology, University of Otago, PO. Box 56, Dunedin, New Zealand (Received 12 June 2000; revised 19 September 2000; accepted 12 October 2000) We used nestedness analysis to seek non-random patterns in the structure of component communities of metazoan parasites collected from 31 sympatric fish species from the northeastern Bothnian Bay, the most oligohaline area of the Baltic Sea. Only 8 marine parasite species were found among the 63 species recorded, although some marine fish species reproduce in the bay and others occasionally visit the area. Marine parasite species can utilize both freshwater and marine fish species as intermediate or final hosts, and marine fish can harbour freshwater parasite species. This exchange of parasite species between marine and freshwater fish has probably resulted from ecological factors acting over short time scales rather than from evolutionary processes acting over longer time; the key factor probably being the immediate presence of suitable intermediate and definitive hosts. Marine fish were expected to harbour species-poor parasite communities consisting mainly of generalists acquired from the sympatric freshwater fish species, which would result in a nested pattern among the different component communities. However, an anti-nested pattern was found in the component communities of metazoan parasites of fishes from the Bothnian Bay. A likely explanation for the observed pattern is that there are specialist parasite species, the majority of which are cestodes, in some of the freshwater fish species which otherwise have depauperate parasite communities.
    [Show full text]
  • HELCOM Red List of Threatened and Declining Species of Lampreys and Fishes of the Baltic Sea
    Baltic Sea Environment Proceedings No. 109 HELCOM Red list of threatened and declining species of lampreys and fishes of the Baltic Sea Helsinki Commission Baltic Marine Environment Protection Commission Baltic Sea Environment Proceedings No. 109 HELCOM Red list of threatened and declining species of lampreys and fishes of the Baltic Sea Helsinki Commission Baltic Marine Environment Protection Commission Editor: Dr. Ronald Fricke, Curator of fishes, Ichtyology Contact address: Staatliches Museum für Naturkunde Stuttgart Rosenstein 1, 70191 Stuttgart, Germany E-mail: [email protected] Photographs © BfN, Krause & Hübner. Cover photo: Gobius niger For bibliographic purposes this document should be cited to as: HELCOM 2007: HELCOM Red list of threatened and declining species of lampreys and fish of the Baltic Sea. Baltic Sea Environmental Proceedings, No. 109, 40 pp. Information included in this publication or extracts there of is free for citing on the condition that the complete reference of the publication is given as stated above. Copyright 2007 by the Baltic Marine Environment Protection Commission - Helsinki Commission ISSN 0357-2944 Table of Contents 1 Introduction .......................................................................................................................6 2 Species and area covered.............................................................................................7 2.1 Species covered..............................................................................................................7
    [Show full text]