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Monday 5 April 2004, 11.30 am (Tas time)
CSIRO Auditorium, Hobart
Henry Kaspar
Aquaculture Group
Cawthron Institute, New Zealand
Overview, aquaculture research, larval rearing and selective
breeding of the pacific oyster
The Cawthron is a small independent organisation providing
R&D and laboratory services for a wide range of clients. Most of
our work relates to the aquatic environment and the needs of primary
industries and local authorities. Coastal ecology, shellfish aquaculture,
marine biosecurity, and river ecology are our main themes.
The Aquaculture Group focuses on shellfish: Greenshell mussel, Pacific
oyster, Abalone. Current topics are: larval rearing, spat retention,
algae production, genetics, selective breeding, cryopreservation, shellfish
health. Most of the research is funded by the NZ Government, but we
also have significant projects with industry partners.
Larval rearing: Cawthron’s Ultra Density Larval System (CUDLS)
is based on a flow-through rather than batch-wise water exchange. Flow-through
allows optimal food delivery and waste removal. Larvae have been reared
for their first week at densities of over 1000 per ml without detrimental
effects on growth and survival. The increase in larval density has resulted
in water savings of up to 45% and a reduction in tank volume by 99%
over the equivalent static system. The system has yielded over 35 million
eyed larvae (>350µm) after 18 days at 22ºC from two 170
litre tanks with each tank exchanging water at 3.5 litres per minute.
Selective breeding: A Pacific oyster breeding program was begun by
Cawthron in 1999. A trial comparing nine families with mixed wild spat
confirmed the potential for significant gains demonstrated by others.
The second cohort (60 families) gave 19% better bag weight for F1 families
compared with wild families. The third cohort (23 wild and 37 advanced-generation
families) was dispatched to the farms last month. The benefits of the
programme are already enjoyed by growers buying commercial spat from
us.
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