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Invertebrate discard viability and fitness in prawn trawl fisheries

Objective

I have developed methodologies using physiological and behavioural measurements to assess the long term viability and fitness of Nephrops discards following capture by trawling (project FAIR CT95-0753). This approach, commended by the assessor of the project, uses important behaviours such as escape reactions, burrowing, defence responses, and the measurement of key physiological variables as indicators of the degree of stress to which fished animals are subjected. These predictors of "fitness" will be applied in a previously unstudied context, namely the Portuguese prawn fishery, within the proposed collaboration. The host researchers, CCMar, will acquire this technology and experience of the approach, including on-board physiological sampling of blood and tissues. The results will increase our understanding of the condition and fate of discarded animals and allow comparisons between Northern and Southern fisheries of the consequences of trawling for crustaceans of commercial importance on non-target epibenthic and infaunal invertebrate populations and, therefore, seabed diversity.

The research builds upon the expertise of both the Fellow and the CCMar group (Dr M.Castro-in-Charge), bringing together two aspects of fishery research to help to reduce the problems of ecosystem conservation and stock depletion created by discarding. This is a problem common to all trawl fisheries in the EU. The new methodology goes beyond considering survival per se, and examines a more complex condition of "fitness" in discards. Thus the findings will assist prediction of the longer - term viability of discards and their chances of success in re-colonising the seabed, avoiding predators and regenerating populations. It will provide new information to aid evaluation of the continued effects of trawling on the biodiversity and abundance of seabed communities, including breeding stocks of species which may be food for target species. Potentially it will allow the identification of procedures which reduce the impact of discarding, yet allow sustainable exploitation of the valuable Nephrops and prawn fisheries with reduced damage to the benthic biota.

Funding Scheme

RGI - Research grants (individual fellowships)

Coordinator

UNIVERSIDADE DO ALGARVE
Address
Campus De Gambelas
8000 Faro
Portugal