Acronym NA
Category
Fisheries
Title Timing and determination of fecundity and skipped spawning: implications for stock-recruitment theory of determinate spawners Programme National Programme
Instrument (FP6)
Contact Type (FP7)
Strand (Interreg)
NA
Theme (FP7)
Activity Area (FP6)
Regional Area (Interreg)
Action (COST)
NA
Specific Programme (FP7)
NA
Funding source National Coordinator Olav Sigurd Kjesbu Coordinator email olav.kjesbu@imr.no
Coordinator institution
IMR - Institute of Marine Research (Norway)
Institutions involved
NA
Start year 2006 End year 2009 Funding (€) € 597,384 Website NA Summary To forecast stock size is an integral part of responsible and sustainable management of marine resources, and requires intimate knowledge of stock-recruitment relationships. Models that accurately depict these relationships have therefore long been sought . These models have evolved in complexity from models using correlations between spawning stock biomass and recruitment, to models incorporating the individual state of the spawning females. Incorporating basic biological knowledge is fundamental for construction of realistic population dynamics models. However, in determinant spawners, emerging evidence suggest that there may also be a critical time window during early vitellogenesis, which is highly influential for potential fecundity. This time window is likely also linked to the decision to skip spawning, a common occurrence among many mature fish. The energy reserves of the mature population during this time window may therefore have considerable important implications for stock recruitment theory, y et this has never been tested. We will use Northeast Arctic cod (NEA) and Norwegian Spring Spawning (NSS) herring as the study species in a combined laboratory, field and modelling approach, to test the hypothesis that there are sensitive periods where energy levels of individual females are either directly linked to the decision to skip spawning or the potential fecundity of spawning females. All data obtained will be implemented into existing life history and stock recruitment models for these species to improve the models explanatory power. If the same general decision rules for skipped spawning and potential fecundity applies for NEA and NSS, this indicates that similar relationships may be relevant to a large number of commercially important species.
We will test the hypothesis that there are sensitive periods where energy levels of individual females are either directly linked to the decision to skip spawning or the potential fecundity of spawning females. Specifically we will examine if: (1) Potential fecundity and proportion of skipped spawners can be linked to condition during a specific time period in a laboratory setting for Northeast Arctic cod; (2) Field data on wild populations can be used to forecast the potential fecundity of the spawning stock and the proportion of skipped spawners for Northeast Arctic cod and herring; (3) Otolith growth patterns at seasonal and daily level can be used to identify the occurrence of skipped spawners in recent years and potentially also linked to the state of the individual fish for Northeast Arctic cod; (4) Data obtained in the laboratory, field and otolith/scale studies can be implemented into existing life history and stock recruitment models to improve their explanatory power.
Keywords
Cod;
Fish stocks;
Herring;
Fish biology;
Fish;
Recruitment;
Marine Region
42
Barents Sea (27.I)
41
Norwegian Sea (27.IIa)
2
Marine Region Map
