Selective breeding in
aquaculture and research
European Network for the Dissemination of Aquaculture
RTD Information (Q5CA-2000-30105) and previously FAIR-3837, Aquaflow ref. :
TL2003-182
Over recent years, the prospect for substantial
genetic improvement has been well documented in some farmed fish species,
specially in Atlantic salmon. A faster growing fish will make more efficient
use of the available feed resources and will also require less culture area
per unit of output, as compared to a slower growing fish. Genetic
improvement is also important in order to get full benefits of management
improvements. In addition, the extremely high fecundity in fish species
facilitates concentration of available resources in a limited number of
breeding centres. Genetic gain in nucleus can be disseminated extensively
throughout the entire industry, with minimum delay, through one or two
levels of multipliers.
Stofnfiskur in Iceland is a fish breeding company
with an established breeding programme for Atlantic salmon, Artic charr,
Rainbow trout and Red Abalone. Stofnfiskur’s most recent activity is to
design a breeding programme for Atlantic cod (Gadus morhua) through
the company ICECOD. Fish farming of cod is now seen as a future industry in Iceland. At
present there is no organized breeding programme for cod in Iceland. Earlier
rearing experiments indicate that breeding goals for cod are in many ways
the same as for Atlantic salmon and Arctic charr. Poor growth, low survival
rate of juveniles, early onset of maturity and quality factors are the most
significant biological factors; which have to be dealt with in the future by
the cod farming industry.
The first step when starting a breeding programme is
to collect the genetic material that forms the base population and to
estimate genetic parameters. Base population is a group of animals with
unknown parents in genetic evaluations. For example, the Atlantic salmon now
used in aquaculture was originally sampled from 40 rivers in Norway. The
base population for cod will be formed by using wild brood fish caught from
different locations off the Icelandic coast. A carefully designed base
population allows the maintenance of a broad genetic variability that allows
long-term selection response and stepwise inclusion of new traits in the
breeding goal.
In this project, a computer simulation model will be
used to estimate the optimal number of individuals/families needed (numbers
of dam and sire per year), to maximize the gain of genetic improvement at
the lowest possible cost. The model will also consider restricting
factors e.g. inbreeding rate. Estimation of genetic parameters requires a
full pedigree and rearing of a large number of fish from known families and
systematically measuring routine under strict statistical methods. Usually
physical tagging has been used to be able to identify individuals in a
rearing unit, where each family has to be held separately until the fishes
have reached the size of tagging. This requires large rearing facilities
with many rearing units. On the contrary, the increased availability of DNA
markers has revolutionised the possibilities of individual identification.
For parental assignment, microsatellites is the most commonly used genetic
marker. The biggest advantage to this new method is the improved use of
space and labour since the families of cod do not have to be kept in
separate units after the hatching of ova.
In this cod-breeding programme, DNA microsatellites
will be used as the only markers for individual identification. The
cod-breeding programme is set to start in 2003 and is a long-term research
project, which will run for several years.
For more information, contact:
T.
Kristjansson
Stofnfiskur hf.
Stadarberg
2-4
221 Hafnarfjordur
Iceland
Tel: (354) 564 6300
Fax : (354) 564 6301
e-mail: theodor@stofnfiskur.is