effect of marine environmental factors, i.e. depth, SST, SBT, SSS and SBS, on whiting abundance.
The North Sea whiting population has fluctuated dramatically over the past 80 years, particularly over the past 40 years. CPUE from trawl surveys does not reflect the decline of whiting abundance in the North Sea, indeed survey catch rate has increased since the early 1970s. However, the dominant contribution to the survey CPUE was from small fish with length < 20cm, which are less than the minimum landing length. SSB is negatively correlated with abundance of small fish (length <20cm) and positively correlated with abundance of large-size fish (>20cm) in survey catches, suggesting that size-based indicators could have been used to determine stock trends. There has been no significant spatial shift of fish abundance. In both winter and summer, whiting abundance is highest in water of around 120m depth. Abundance also decreases at high SST values.
An ecosystem approach to aquaculture management.
1, Culhane F1, Fernandes T1, Potts T2, Valcic B2, & Tett P1
1Edinburgh Napier University, Edinburgh, EH14 1DJ, Scotland, UK
2Scottish Association for Marine Science, Dunstaffnage Marine Laboratory, Oban PA37 1QA,
Science and Policy Integration for Coastal System Assessment (SPICOSA) is a European framework six project involving 22 countries and 54 partners across Europe. Scientists including ecologists, economists and sociologists are working together to create methodologies and models to aid coastal managers. One of the study sites chosen for this project was Loch Fyne in the upper reaches of the Firth of Clyde. Local Stakeholders voiced concern that a proposed increase in leisure boating could place pressure on marine aquaculture in the loch by increasing the load of anti foulant compounds in the water, detrimentally affecting the health of the phytoplankton. A model has been constructed which will allow the effect of anti-foulants on the phytoplankton population to be investigated. The methodology used to conceptualise and construct this model as well as preliminary results will be presented.