Parasite load of Atlantic cod Gadus morhua in the Baltic Sea assessed by the liver category method, and associations with infection density and critical condition

During the 2010s, Atlantic cod Gadus morhua L. in the eastern Baltic Sea experienced increasing infection loads of the parasitic nematode Contracaecum osculatum (Rudolphi) in their livers. Starting in 2021, a mandatory part of the routine sampling protocol on Baltic monitoring surveys is to assign a...

Full description

Saved in:
Bibliographic Details
Published in:Fisheries management and ecology 2022-02, Vol.29 (1), p.88-99
Main Authors: Ryberg, Marie Plambech, Huwer, Bastian, Nielsen, Anders, Dierking, Jan, Buchmann, Kurt, Sokolova, Maria, Krumme, Uwe, Behrens, Jane W.
Format: Article
Language:English
Subjects:
disease monitoring
eastern Baltic cod
Fish
Fish diseases
Fish stocks
Fulton condition factor
Gadus morhua
Infections
Liver
liver worm
Loads (forces)
Marine fishes
Monitoring
natural mortality
Nematodes
Parasites
Probability theory
stock assessment
Surveys
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:During the 2010s, Atlantic cod Gadus morhua L. in the eastern Baltic Sea experienced increasing infection loads of the parasitic nematode Contracaecum osculatum (Rudolphi) in their livers. Starting in 2021, a mandatory part of the routine sampling protocol on Baltic monitoring surveys is to assign a liver category to individual cod livers, based on the number of nematodes visible on the liver surface, to follow spatiotemporal changes in nematode infection loads. The validity of the liver category method has never been evaluated. Based on data from 642 cod livers, the method was verified and found to be a good predictor of the total number of nematodes. Moreover, the probability of cod being in a critical condition increased with the parasite load. In addition to their direct applicability to Baltic cod, the present findings may inspire others working with disease in fish stocks to include parasite monitoring.
ISSN:0969-997X
1365-2400
DOI:10.1111/fme.12516