Effects of the seal-associated cods liver worm (Contracaecum osculatum) on the health status of Eastern Baltic cod

Description

Eastern Baltic cod (Gadus morhua) is in distress,
revealed by historical poor nutritional status and few
large fish. Known drivers of this are poor oxygen
conditions and reduced food, but an additional
driver may be the seal-associated cods liver worm
(Contracaecum osculatum). We here describe effects
of varying infections intensities of liver worm on cod
health status, bioenergetics and mortality
The Eastern Baltic cod (Gadus morhua) is in distress.
Today these fish are in a historical poor nutritional
status (i.e. condition), growth has decreased, and
large individuals are few. Known drivers of the
stock into this distress are deteriorating oxygen
conditions and reduced prey abundance. However,
yet another potential driver of the health status
of cod has emerged; the seal-associated cods liver
worm (Contracaecum osculatum) to which grey seal
is final host and cod one of several transport hosts.
During recent years, infection load with this parasite
in cod livers has increased markedly. The liver is a
central organ for many vital processes related to e.g.
growth and immune response, and it is an energy-rich
‘lunch box’ for the fish, and high parasite load may
negatively affect the fish.
We here present data describing effects of varying
infections intensities of liver worm on the health
status, bioenergetics and mortality of cod. Results
are evaluated in relation to their applicability in
bioenergetic modelling, contributing with new
biological information to assessment models of
Eastern Baltic cod.

Period	23 Aug 2019
Held at	Baltic Sea Science Congress 2019
Event type	Conference
Location	Stockholm, Sweden