Increasing occurrence of anisakid nematodes in the liver of cod ( Gadus morhua ) from the Baltic Sea: Does infection affect the condition and mortality of fish?

2016 ◽  
Vol 179 ◽  
pp. 98-103 ◽  
Author(s):  
Jan Horbowy ◽  
Magdalena Podolska ◽  
Katarzyna Nadolna-Ałtyn
Keyword(s):  
Baltic Sea ◽  
Gadus Morhua ◽  
The Baltic Sea ◽  
The Baltic ◽  
Anisakid Nematodes

scholarly journals Contracaecum osculatumand other anisakid nematodes in grey seals and cod in the Baltic Sea: molecular and ecological links

2017 ◽  
Vol 92 (1) ◽  
pp. 81-89 ◽  
Author(s):  
S. Zuo ◽  
P.W. Kania ◽  
F. Mehrdana ◽  
M.H. Marana ◽  
K. Buchmann
Keyword(s):  
Baltic Sea ◽  
Gadus Morhua ◽  
Final Host ◽  
The Baltic Sea ◽  
Fish Stocks ◽  
Pseudoterranova Decipiens ◽  
Contracaecum Osculatum ◽  
The Baltic ◽  
The Impact ◽  
Anisakid Nematodes

AbstractPopulations of grey seals (Halichoerus grypus), sprats (Sprattus sprattus) and cod (Gadus morhua) in the Baltic Sea are relatively stationary. The present work, applying classical and molecular helminthological techniques, documents that seals and cod also share a common parasite, the anisakid nematodeContracaecum osculatum, which uses seals as the final host and fish as transport hosts. Sequencing mitochondrial genes (COX1andCOX2) in adult worms from seals and third-stage larvae from livers of Baltic fish (sprats and cod), showed that all gene variants occur in both seals and fish. Other anisakid nematodesPseudoterranova decipiensandAnisakis simplexare also found in both seals and cod in the Baltic Sea, but at much lower rates. The Baltic grey seal population was left at a critically low level (comprising a few hundred individuals) during the latter part of the 20th century, but since the year 2000 a marked increase in the population has been observed, reaching more than 40,000 individuals at present. Ecological consequences of the increased seal abundance may result from increased predation on fish stocks, but recent evidence also points to the influence of elevated parasitism on fish performance.Contracaecum osculatumlarvae preferentially infect the liver of Baltic cod, considered a vital organ of the host. Whereas low prevalences and intensities in cod were reported during the 1980s and 1990s, the present study documents 100% prevalence and a mean intensity of above 80 worms per fish. Recent studies have also indicated the zoonotic potential ofC. osculatumlarvae in fish, following the consumption of raw or under-cooked fish. Therefore the present work discusses the impact of parasitism on the cod stock and the increasing risk for consumer health, and lists possible solutions for control.

scholarly journals Deoxygenation impacts on Baltic Sea cod: Dramatic declines in ecosystem services of an iconic keystone predator

AMBIO ◽  
2021 ◽  
Author(s):  
Alessandro Orio ◽  
Yvette Heimbrand ◽  
Karin Limburg
Keyword(s):  
Ecosystem Services ◽  
Baltic Sea ◽  
Gadus Morhua ◽  
Generalized Additive Model ◽  
Additive Model ◽  
Maximum Length ◽  
The Baltic Sea ◽  
Hypoxic Zone ◽  
The Baltic ◽  
Baltic Cod

AbstractThe intensified expansion of the Baltic Sea’s hypoxic zone has been proposed as one reason for the current poor status of cod (Gadus morhua) in the Baltic Sea, with repercussions throughout the food web and on ecosystem services. We examined the links between increased hypoxic areas and the decline in maximum length of Baltic cod, a demographic proxy for services generation. We analysed the effect of different predictors on maximum length of Baltic cod during 1978–2014 using a generalized additive model. The extent of minimally suitable areas for cod (oxygen concentration ≥ 1 ml l−1) is the most important predictor of decreased cod maximum length. We also show, with simulations, the potential for Baltic cod to increase its maximum length if hypoxic areal extent is reduced to levels comparable to the beginning of the 1990s. We discuss our findings in relation to ecosystem services affected by the decrease of cod maximum length.

scholarly journals An ecosystem model of food web and fisheries interactions in the Baltic Sea

2003 ◽  
Vol 60 (5) ◽  
pp. 939-950 ◽  
Author(s):  
Chris J Harvey ◽  
Sean P Cox ◽  
Timothy E Essington ◽  
Sture Hansson ◽  
James F Kitchell
Keyword(s):  
Baltic Sea ◽  
Food Web ◽  
Species Interactions ◽  
Gadus Morhua ◽  
Population Analysis ◽  
Clupea Harengus ◽  
Trophic Relationships ◽  
The Baltic Sea ◽  
Management Actions ◽  
The Baltic

Abstract Because fisheries operate within a complex array of species interactions, scientists increasingly recommend multispecies approaches to fisheries management. We created a food web model for the Baltic Sea proper, using the Ecopath with Ecosim software, to evaluate interactions between fisheries and the food web from 1974 to 2000. The model was based largely on values generated by multispecies virtual population analysis (MSVPA). Ecosim outputs closely reproduced MSVPA biomass estimates and catch data for sprat (Sprattus sprattus), herring (Clupea harengus), and cod (Gadus morhua), but only after making adjustments to cod recruitment, to vulnerability to predation of specific species, and to foraging times. Among the necessary adjustments were divergent trophic relationships between cod and clupeids: cod exhibited top-down control on sprat biomass, but had little influence on herring. Fishing, the chief source of mortality for cod and herring, and cod reproduction, as driven by oceanographic conditions as well as unexplained variability, were also key structuring forces. The model generated many hypotheses about relationships between key biota in the Baltic Sea food web and may ultimately provide a basis for estimating community responses to management actions.

Environmental genotoxicity and cytotoxicity levels in herring (Clupea harengus), flounder (Platichthys flesus) and cod (Gadus morhua) inhabiting the Gdansk Basin of the Baltic Sea

2018 ◽  
Vol 133 ◽  
pp. 65-76 ◽  
Author(s):  
Roberta Valskienė ◽  
Janina Baršienė ◽  
Laura Butrimavičienė ◽  
Wlodzimierz Grygiel ◽  
Virmantas Stunžėnas ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Gadus Morhua ◽  
Clupea Harengus ◽  
The Baltic Sea ◽  
Platichthys Flesus ◽  
The Baltic ◽  
Environmental Genotoxicity

scholarly journals Relationships between fish stock changes in the Baltic Sea and the M74 syndrome, a reproductive disorder of Atlantic salmon (Salmo salar)

2011 ◽  
Vol 68 (10) ◽  
pp. 2134-2144 ◽  
Author(s):  
Jaakko Mikkonen ◽  
Marja Keinänen ◽  
Michele Casini ◽  
Jukka Pönni ◽  
Pekka J. Vuorinen
Keyword(s):  
Atlantic Salmon ◽  
Baltic Sea ◽  
Salmo Salar ◽  
Gadus Morhua ◽  
Clupea Harengus ◽  
Fish Stock ◽  
The Baltic Sea ◽  
Atlantic Salmon Salmo Salar ◽  
Reproductive Disorder ◽  
The Baltic

Abstract Mikkonen, J., Keinänen, M., Casini, M., Pönni, J., and Vuorinen, P. J. 2011. Relationships between fish stock changes in the Baltic Sea and the M74 syndrome, a reproductive disorder of Atlantic salmon (Salmo salar). – ICES Journal of Marine Science, 68: 2134–2144. The M74 syndrome of Baltic salmon (Salmo salar), which appears as increased yolk-sac fry mortality (YSFM), impairs the reproduction of salmon stocks. Changes in the prey stocks of Baltic salmon in its two feeding areas, the southern Baltic Proper (BPr), where sprat (Sprattus sprattus) was the main prey species during the high incidence of M74, and the Bothnian Sea, where herring (Clupea harengus) is the dominant species, were analysed in relation to salmon growth and size and in relation to the incidence of M74. The high condition factor (CF > 1.05) of prespawning salmon predicted high YSFM. From the various stock factors of sprat and herring in the southern BPr, the biomass of sprat had the strongest positive relationships with the CF of prespawning salmon, and the total prey biomass with YSFM. It is concluded that the ample but unbalanced food resources for salmon in the BPr, primarily sprat, induce M74. By reducing the fishing pressure on cod (Gadus morhua) and by more effectively managing the sprat fishery in years when the cod stock is weak, the incidence of the M74 syndrome could be reduced and even prevented.

scholarly journals ON THE MINIMUM COMMERCIAL COD SIZE GADUS MORHUA CALLARIAS IN THE BALTIC SEA

2019 ◽  
Vol 20 (1) ◽  
pp. 73-82
Author(s):  
V.M. Amosova ◽  
◽  
A.S. Zezera ◽  
A.I. Karpushevskaya ◽  
I.V. Karpushevskiy ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Gadus Morhua ◽  
The Baltic Sea ◽  
The Baltic

scholarly journals Nematode Parasites in Baltic Sea Mammals, Grey Seal (Halichoerus grypus (Fabricius, 1791)) and Harbour Porpoise (Phocoena phocoena (L.)), from the German Coast

2020 ◽  
Author(s):  
Michael Gabel ◽  
Stefan Theisen ◽  
Harry Wilhelm Palm ◽  
Michael Dähne ◽  
Patrick Unger
Keyword(s):  
Baltic Sea ◽  
Parasite Species ◽  
Parasite Fauna ◽  
Eastern Coast ◽  
Halichoerus Grypus ◽  
Phocoena Phocoena ◽  
The Baltic Sea ◽  
Nematode Parasites ◽  
The Baltic ◽  
Anisakid Nematodes

Abstract Purpose Endoparasitic nematodes of six harbour porpoises Phocoena phocoena and four grey seals Halichoerus grypus, stranded at the eastern coast of the Baltic Sea in Germany in winter 2019, were analysed in order to identify nematode parasites and to compare with recent studies from the same area. Methods Endoparasitic nematodes were identified by using both morphological and molecular characters. The successfully obtained sequences of the rDNA marker regions ITS-1, 5.8S, ITS-2 from 29 anisakid and the rDNA marker region ITS-2 of 11 pseudalid nematodes were amplified. Results Analyses revealed the presence of three parasite species, the anisakid nematode Contracaecum osculatum from grey seals and the pseudalid nematodes Pseudalius inflexus and Stenurus minor from the harbour porpoises. Other anisakid nematodes regularly occurring in the Baltic Sea, e.g. Anisakis simplex or Pseudoterranova decipiens, were not found. Conclusions The prevalence of 100% and a severe parasite load in grey seals demonstrated a very high C. osculatum infection of Baltic Sea fish as their regular prey. Prevalence of 33% for parasites in harbour porpoises and minor infection rates, combined with a distinct lack of anisakid nematodes, are typical for the current situation of the porpoise parasite fauna in the Baltic Sea. Invasive parasite species as possible indicators for climate change could not be detected.

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