Spatial dynamics of range expanding Gilt-Head Bream in UK inshore waters

Lead Research Organisation: University of Exeter
Department Name: Biosciences

Abstract

With species range shifts and expansions due to climate change it is essential to identify potential new target species for UK fisheries and aquaculture and to ensure the sustainable exploitation of these new and shifting resources through appropriate regulation. CEFAS - the Centre for Environment, Fisheries and Aquaculture Science - is currently conducting a project("C-Bass") to study and model spatial population dynamics of European sea bass to support the conservation of this commercially and recreationally important fish species. A stated aim of that project is to apply the methodology that is being developed for bass to a number of other important species, including gilthead bream (Sparus aurata). The latter is, commercially and recreationally, one of the most sought after warm-temperate marine fish species in Europe. It has been the subject of aquaculture in the Mediterranean Sea for many centuries and is currently the most prolifically farmed fish there. Predominantly a warm water fish, the northern limit of its range is in the English Channel and Celtic Sea. The rise of sea surface water temperatures, as a consequence of climate change, is thought to be responsible for an apparent range expansion of gilthead bream in recent decades, with the species now being commonly caught in a number of Cornish estuaries. With further climate warning this species is likely to expand its range further along the British coast.
This studentship project is a collaboration between CEFAS and the University of Exeter's Centre for Ecology and Conservation in Cornwall. The overall aims are to gain a better understanding of the local population ecology and movements of gilthead bream. Using a variety of techniques (tagging, analysis of growth rings in earbones, diet analysis etc) we will determine: to what extend fish in Cornwall are migrants or locally born and bred; what the size- and age-structure is of the population (especially important because gilthead bream start life as male and undergo sex change to become female in their 3rd or 4th year); how much the fish move between estuaries; where the fish spend the winter months (Southern Europe or deep water off Cornwall?); and how this species is integrated in the local food web - which
prey does it eat at different ages? This information will be fed into models to predict this species' further range expansion, based on climate predictions, and will then be used to develop a spatial population model (based on the C-Bass model) that can be used to inform management of this valuable species. This collaboration between CEFAS and the University of Exeter will provide the student with excellent training in fundamental population biology that is directly relevant to fisheries management. The UoE Penryn campus in Cornwall is geographically ideally situated and the academic supervisors have the expertise required to succesfully lead the field based research. This collaboration provides CEFAS therefore with an excellent opportunity to expand their stakeholder-driven research to a new and important species. In return, the University of Exeter benefits from the high level of expertise in all aspects of fisheries research at CEFAS which allows for the development of a new study system with real impact
potential on the Penryn Campus doorstep.

Publications

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Description Gilthead bream (Sparus aurata) is a popular target for recreational and commercial fisheries. In response to sea temperature warming, the species has established persistent populations in southern areas of the UK over recent decades. Understanding of its populations will benefit sea-anglers and fishermen, the related coastal tourism sector and conservationists managing the long term sustainability of inshore fisheries. Our current research, in collaboration with CEFAS and Cornwall IFCA, focusses on the ecology and population structure of this species in UK waters. Knowledge of this population structure will provide us with information on the extent to which our local population acts as an isolated self-sustaining unit, a sink or indeed a source for other Atlantic populations. This is important information for informing any potential future management of the population, which is likely to start with local voluntary action (short-term impact). We have good links with local recreational angling clubs, who plan to start using our data to propose voluntary catch size limits for members in the near future to help ensure fish reach reproductive maturity before being retained.
First Year Of Impact 2016
Sector Leisure Activities, including Sports, Recreation and Tourism
Impact Types Societal