SARF027: Research and development of stock management strategies to optimise growth potential in ongrowing of marine fish

Start Date: 1/2/07
End Date: 31/01/10
Main Contractor(s): University of Stirling
Other Sponsor(s): BMFA & Intravision Aqua AS

Objectives

1) Determine the feasibility of semen sexing by flow cytometry in both Atlantic halibut, Atlantic cod and other commercially important UK species and develop, if successful, protocols for all female production.

2) Provide the guidance and practical help in establishing a "neomale" halibut population at a commercial hatchery which could be used in future years to produce all female halibut populations and optimisation of the technique.

3) Determine light sensitivity threshold and welfare impact of artificial lighting in cod: study the impact of different lighting intensities on light perception and welfare/immune impacts in tanks representative of a cage system using new lighting technologies (CCL and/or LEDs).

4) Develop and validate molecular tools to determine the initiation of puberty in marine fish species.

5) Determine the size regulation of recruitment into puberty in cod: study the ontogeny of puberty through molecular expression study of kisspeptin related gene

Summary

The British marine aquaculture industry has identified that a delay or cessation of maturation during on-growing is crucial for profitable farming as maturation in marine fish species usually results in a loss of somatic growth rate, reduction in condition, change in flesh composition and up to at least a 25% loss in wet weight in cod for example .To date, there are no protocols that can be reproducibly employed by the industry to overcome this problem in cod or halibut fish farming. Critically, although seasonally-changing day-length (photoperiod) has been demonstrated to be the natural time-keeping mechanism used by finfish from temperate latitudes to entrain a number of important physiological processes, including sexual maturation(3), the complex mechanisms behind the photoperiodic control of puberty are still unclear. For example the precise timing of recruitment and the somatic regulation of puberty (i.e. size at which fish can enter into reproduction) are unclear in many species. As such the management of sexual maturation on farm remains unpredictable and limits profitability. This project is thus designed to provide significant steps forward in the refinement of potential reproduction management strategies that could be employed by the UK marine farming industry as well as developing new tools to further our understanding of puberty.