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

COMPREHENSIVE QUALITY ASSESSMENT OF ATLANTIC COD (Gadus morhua L.)
FARMED UNDER DIFFERENT LIGHT REGIMES
Ørjan Hagen* and Christel Solberg
Faculty of Biosciences and Aquaculture
Bodø University College
NO-8049 Bodø, Norway
In Norwegian aquaculture, Atlantic cod is considered to be the next rising star due to it world wide popularity and so far promising
industrial results. To date, one of the largest challenges in the grow-out phase is high production cost due to precocious
maturation and slow growth. Superimposed on this, quality problems during the summer, particularly soft texture and gaping,
makes harvesting a “risky” business. This is unfortunate since the concept of fish farming is based on whole year harvest, and
particularly in periods when the price and demand is good (e.g. the summer).
Light manipulation as a mean to delay maturation and stimulate growth has not yet been very successful in large scale cod farming.
At the most, maturation has only been delayed with up to 6 months. One potential way of reducing the quality problems
during the summer is to apply existent light technology on both accelerated and delayed maturation. This would ensure that
netpens exposed to different light regimes matures at different times of the year, making harvesting of sub populations possible
during the whole year and therefore limit the fillet quality problems in the summer. To test this theory, a large scale experiment
was conducted outside Bodø (Norway) at a commercial farm site. In the present experiment (01.08.07–20.06.08) a total of five
netpens were included (n=60.000 each). Four netpens received a light regime causing delayed (DG) or accelerated maturation
(AG) respectively (two each), and one netpen contained the control group (CG, ambient conditions). Growth and maturation
status was monitored by sampling 30 individuals from each netpen from 05.12.07–20.06.08 (n=4). By the end of the experiment,
both AG and DG had outgrown CG with > 0.8 kg (P