Protective measures against
infectious diseases in the rearing of cold water marine species
European Network for the Dissemination of Aquaculture
RTD Information (Q5CA-2000-30105) and previously FAIR-3837, Aquaflow ref. :
TL2003-165
Cultivation of marine fish
species such as cod, turbot and wolfish is developing in Iceland and halibut
cultivation is becoming an industry. However more information on potential
pathogens of these species and the relevant protective
measures to be applied is lacking.
The losses of larvae and young fry are still far too high and there are some
indications that bacterial infections are involved. There is also a lack of
good vaccines and knowledge regarding when in the cultivation process and at
which time of the year vaccination is most appropriate.
The aim of this project is to study the
susceptibility of cod, halibut and turbot to the main bacterial pathogens of
salmonids in Iceland; Aeromonas
salmonicida, subsp. achromogenes;
Moritella viscosa; Vibrio
salmonicida and Vibrio
anguillarum; To develop experimental challenge models; To isolate and
characterize bacteria from the fish and its environment; To study survival
of fish larvae and young fry bathed in preparations of characterized
bacteria belonging to the natural flora at the hatchery; To vaccinate cod,
halibut and turbot with a polyvalent vaccine including the named bacteria as
antigens and to study the effect of vaccination on fish growth and
protection in challenge experiments.
Experimental challenge tests have revealed that all
the named fish species are susceptible to infections by the bacterium A.
salmonicida, subsp. achromogenes, which
has been the main pathogen in farming of salmonid fish in Iceland. M. viscosa infections cause considerable problems in salmon farming
and the results show that cod is also highly sensitive to infections and
turbot is sensitive at temperatures below 10°C. Halibut was found to be
more resistant, although the bacterium was able to multiply and induce
pathology in halibut. Challenge models have been established and seven
bacterial species isolated from cod have been characterized and used for
bathing of cod larvae in order to study their probiotic effects. Vaccination
experiments of halibut and turbot have been performed and the results are in
one published paper and two manuscripts are in preparation. Further studies
will involve the examination of probiotic effects of a bacterial strain on
survival of cod larvae and improvement of protection induced in cod fry
against V. anguillarum, A. salmonicida, subsp. achromogenes, and M. viscosa challenges. Two scientific papers have
been published with results from the study and two manuscripts are in
preparation. The research programme will be completed in 2006.
*Funding:
The Ministry of Fisheries, RANNÍS and ALPHARMA Inc. (Vaccine producer)
For more information, contact:
Bjarnheiður K. Guðmundsdóttirr
Institute for Experimental Pathology
University of Iceland
Keldur v. Vesturlandsveg
IS-112 Reykjavík - Iceland
E-mail: bjarngud@hi.is