Acronym NA
Category
Fisheries
Title Improved advice for the mixed herring stocks in the Skagerrak and Kattegat 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 Lotte Worsoe Clausen Coordinator email law@aqua.dtu.dk
Coordinator institution
DTU-AQUA - Technical University of Denmark; National Institute of Aquatic Resources (Denmark)
Institutions involved
NA
Start year 2005 End year 2007 Funding (€) € 87,195 Website NA Summary The ICES working group on Herring Assessment for the Area South of 62ºN (HAWG) has not been able to provide an advice applicable for the stock components in area IIIa due to limited resources to explore on the matter intersessionally. In previous years, the TAC for the fleets fishing herring in Division IIIa have been decided by managers according to recommendations for the North Sea Autumn Spawners (NSAS), raised according to the historical fraction of NSAS in the catches by these fleets. The recommendation for the NSAS was guided by the need to rebuild that stock. By now, the NSAS stock has recovered and the main concern is for the Western Baltic Spring Spawners (WBSS) stock. The HAWG used a simple procedure in 2004 to find the highest total catch by fleet in Division IIIa that would be compatible with a precautionary exploitation of WBSS. This procedure used two kinds of information about the fishery, the fraction of WBSS that is caught in IIIa, and the fraction of the catches by the IIIa fleets that consist of WBSS based on recent historic data. This very crude procedure can be refined with more detailed information on how the stocks on one hand and the fisheries on the other hand are distributed geographically and seasonally. Furthermore, the differences in both distribution and fishing pattern both in terms of season and stock components suggest a scope for a fishery management that is more fishery and stock oriented, allowing for more directed stock-wise exploitation. To ensure the preservation of the diversity of the herring population in IIIa and their natural migration patterns all stock components must be incorporated in advice on the fishery. The primary goal of the project is to improve the assessment and advice of the mixed stock in IIIa by elaborating fleet- and stock-based disaggregation on the existing projection method. The advice would so take into account both stocks and all fleet components in IIIa. Temporal and spatial distribution of the different stock components and fleet exploitation patterns will form the basis for the elaboration.
The project will be developed along three lines: Task 1. Mapping of stock components The migration patterns of the different stock components will be evaluated using existing data in the institute databases and other published material. Based on historical material the spatial and temporal distribution of the NSAS and WBSS in IIIa will be mapped. The current assumption of equal distribution of all stock components in the area with no differentiation regarding geographical and seasonal information will be revised. This task is a prerequisite for Task 2. Task 2. Exploitation by fleets The exploitation pattern and fleet behaviour will be modelled to describe the CPUE and catchability on all stock components. This will allow investigating and simulating how changes in fleet effort would affect the various herring stocks. This in turn will be employed in the model developed in Task 3. Task 3. Improvement of assessment and advice procedures. The assumptions in the current approach for advice will be replaced by more consolidated fractions of the stock components based on the results from Task 1. The calculations will then be combined with multi-fleet short term prediction programs for each stock (Task 2), to outline combinations of total quotas by fleet that are compatible with proposed harvest rules and/or precautionary criteria.
Keywords
Fish stocks;
Stock assessment;
Fisheries management;
Fish;
Herring;
Marine Region
14
Skagerrak, Kattegat (27.IIIa)
1
Marine Region Map
