February 15-18, 2009 Washington State Convention Center Seattle ...

DEVELOPMENT OF INTENSIVE CULTURE METHODS FOR BURBOT Lota lota
Kenneth D Cain, Nathan Jensen, Susan Ireland, John Siple and Matt Neufeld
Department of Fish and Wildlife Resources
and the Aquaculture Research Institute
University of Idaho
P.O. Box 441136
Moscow, ID 83844-1136 USA
kcain@uidaho.edu
Burbot Lota lota are freshwater cod native to Idaho, USA and near demographic extinction from Idaho’s Kootenai River and
British Columbia’s Kootenay River/Lake. Idaho burbot were denied federal listing in 2000 and remain a species of concern.
The Kootenai Tribe of Idaho, the University of Idaho and the British Columbia Ministry of Environment collaborated ca. 2003
and brought wild adult burbot into captivity to develop suitable rearing systems and fundamental hatchery methods as an option
should hatchery burbot be needed to replenish the Kootenai(y) stocks. Over the last five years, observational studies into
adult gender segregation and hormone analog (sGnRha) use have occurred in an attempt to synchronize and control volitional
spawning. An optimal egg incubator design was determined and larval weaning from live diets to commercial larval diets was
evaluated from 2004-2006. Since 2003, facility renovations have occurred annually. The current burbot culture systems in use
consists of full or partial recirculation water systems designed to conserve water and maintain critical water temperatures for
spawning (2-5˚C), egg incubation (3-5˚C), larval feeding and juvenile grow-out (8-20˚C). Additionally, six 8000L fiberglass
tanks are kept outdoors for semi-intensive pond style rearing. Results of spawning observations revealed that volitional (in
tank) spawning is common and fine mesh screens (0.5mm) are needed to keep eggs (typically 1 mm in diameter) within adult
spawning tanks. The optimal egg incubator design is 1L conical bottom upwelling incubators suspended overtop a screened
(0.5mm) 1m circular tank where larvae hatch and collect, develop and begin feeding on live prey. Live prey feeding begins with
brackish (10ppt NaCl) rotifers Brachionus plicatilis mass produced in closed recirculation systems and is followed by Artemia
hatched in 19L water containers (5ppt NaCl). When rotifer feeding ends commercial larval weaning diet (200-600 micron)
feeding begins. Weaning larval burbot to commercial diets, while keeping the rearing environment clean, is the foremost bottle
neck to successful production of healthy juveniles. Therefore, semi-intensive extensive rearing methods are being developed.
All burbot culture system designs and method developments discussed will be applied to create a burbot hatchery manual and
used to design a future conservation breeding program facility aimed at revitalizing burbot populations in Idaho’s Kootenai
River and British Columbia’s Kootenay River/Lake. Such techniques have implications for recovery of burbot populations
elsewhere in the world and have the potential for future commercial aquaculture development of this species.
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