Elucidating the early life history of Faroe Plateau cod and Faroe haddock

Cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) are main demersal fish species on the Faroe Shelf which have always been key fish species for the Faroese community and economy.
The stocks show large fluctuations in year class strengths which has severe economical and sociological consequences. Although there are many bottlenecks affecting the final year class strengths of fish, the early life phase of the individuals (i.e. larval and pelagic juvenile stages) is generally considered to be essential for successful further development.
During the pelagic phase, the fishes undergo a period of rapid development with considerable changes in size, structure, physiology and behavior. Survival of eggs and larvae are mainly dependent on drift and distribution, feeding and growth conditions, and extent of predation.
Monitoring of pelagic 0-group fish on the Faroe Plateau in late June from 1974 until present has revealed large variations in cod and haddock abundance and sizes. Interestingly, the abundance and individual sizes to a large extent seem to co-vary between years, indicating simultaneous environmental influences on mortality and individual sizes.
The aim of this project is to investigate the life history of cod and haddock larvae and pelagic juveniles and to relate this to oceanographical parameters and feeding conditions. The research material is based on field samplings and in situ measurements on the Faroe Shelf on two annual cruises, in late April and late June respectively. The April cruise is placed at a critical time in spring
(late pre-bloom and early bloom phase), studying the match-mismatch between spring bloom development, subsequent zooplankton reproduction, and occurrence of first-feeding fish larvae.
The June cruise is placed close towards the end of the pelagic phase of the juveniles. Historical data and stored samples of cod and haddock larvae and juveniles will be analyzed, together with environmental variables. This information may reveal how growth and survival of cod and haddock
during their pelagic phase is affected by the dynamic environmental conditions on the Faroe Shelf.
Since abundance of 0-group cod and haddock is a relatively good predictor for subsequent recruitment to the fish stocks, such information will be valuable in advice and management of sustainable exploitation of these important fish species in the future.