Halibut Farming Development
Aquaflow Technical Leaflet 2002-83
European Network for the Dissemination of Aquaculture
RTD Information (Q5CA-2000-30105) and previously FAIR-3837, URL: http://www.aquaflow.org/
The rapid development of salmon farming and its
significant contribution to the UK’s fish consumption illustrate what can
be achieved through aquaculture, but only similarly high value species can
be considered if development costs are to be re-couped. Atlantic halibut was
identified as the best prospect for the first phase of the industry’s
development. The
overall objective of this project was to overcome technical and biological
problems, which were recognised as being serious hurdles to the development
of this embryonic sector of the aquaculture industry. It was proposed to bring together a varied consortium
of research and industry groups to allow a multi disciplinary approach to
the following critical areas:
i.
Cost
Effective Broodstock Environmental Control
ii.
Oogenesis and
Dynamics of Egg Production in Farmed Halibut
iii.
Hormonal
Manipulation of Spawning
iv.
Larval
Nutrition, Metamorphosis and Pigmentation
v.
Health:
Immune Response and Parasite Susceptibility
The main achievements of this project include
successful re-circulation techniques adopted for broodstock management at
low temperatures. This included
identification of optimal holding parameters and the evaluation of relative
costs of chilled re-circulation systems for broodstock fish.
The re-circulation system had no detrimental effect on fecundity or
viability of spawning. An improved understanding of egg production
physiology in farmed Atlantic halibut was highlighted by the development of
a dry diet for halibut broodstock. Methods
of gamete quality assessment including the use of ultrasound to
non-invasively establish gender in halibut and also to follow reproductive
development were devised plus a description of seasonal dynamics of oocyte
maturation. Improvements in
larval nutrition, pigmentation and metamorphosis came about with the
development of a recommended diet for halibut larvae in the absence of
cultured copepods, the determination of optimal stages for dietary
transition and the improvement of optimal dietary lipid profiles.
Elements of halibut parasitology and immunology were
investigated including an assessment of potential
parasitic pathogens in culture conditions.
This study provided morphological descriptions and details of the
life cycles under culture conditions of the two most potentially significant
ectoparasites in halibut culture a monogenean Entobdella hippoglossi and
a close relative of the salmon louse Lepeophtheirus hippoglossi.
A formalin treatment strategy for E. hippoglossi was designed
and a novel drug treatment for L. hippoglossi was tested.
Model antigens were produced along with the development of
immunological assays for halibut and the determination of early onset of
immunocompetence. A model of maternal investment in eggs was also established.
The reproduction of Atlantic halibut was also investigated and
the use of GnRHa in the improvement of milt production was established.
This
work was funded by the BBSRC Technology Foresight Challenge and was carried
out in conjunction with Seafish Aquaculture, Ardtoe Dept.
Reproductive Physiology, Parasitology Group, Unit of Aquatic Biochemistry,
Institute of Aquaculture, University of Stirling, Aquaculture & Aquatic
Animal Health Group, FRS Aberdeen, Otterferry Seafish Ltd, Argyll, Finfish
Ltd/Mannin Seafarms, Isle of Man, Orkney Marine Hatcheries, Orkney, British
Marine Finfish Association.
For more information:
GILLESPIE Malcolm
Aquaculture Seafish Industry Authority - Seafish Aquaculture Marine Farming
Unit
Ardtoe, Acharacle, Argyll
PH36 4LD
United Kingdom
E-mail: aquaculture@seafish.co.uk