By Naruepon Sukamasavin *
The Mekong giant catfish (Pangasianodon gigas) is one of the world's largest freshwater fishes. Its status as a critically-endangered species led to the establishment of the Mekong Giant Catfish Working Group in 2005 (see Catch and Culture, Vol 12, No 1). Since then, a mathematical model has been used to reconstruct the dynamics of the population and predict its future development under different scenarios out to 2050 (see Catch and Culture, Vol 13, No 1). Given the depleted state of the population, the working group has developed a conservation strategy with annual harvesting restricted to no more than 10 adults under current conditions and no more than 20 in the longer term.
Fishing limits
At the working group's latest meeting in Udon Thani in April,
it was recommended that only eight mature or nearly mature individuals
could be caught in 2009 since Cambodia had reported incidental
catches of two fish between October and December last year.
Since the fishing limit recommended by the working group relies
solely on the quantitative assessment model which has still
not been intensively reviewed by scientists, it was also recommended
that the model be published and disseminated for intensive peer
review. The working group recommended that all targeted and
known incidental fishing for the species, including a recently-reported
site in a li trap fishery in southern Lao PDR, should be carefully
monitored for research and population assessment as well as
the enforcement of regulations where these are in place. At
the same time, regional cooperation in reporting, exchanging
information and setting biological limits to fishing should
be maintained and strengthened.
Conservation, captive breeding and aquaculture
Habitat and ecosystem conservation are still very important
to ensuring the long-term survival of the Mekong giant catfish
in the wild. Specifi c habitat use and migrations for the species
should be identifi ed and conserved. The possibility of more
spawning grouds Flagship species in the north of Cambodia or
other places needs to be investigated and confi rmed. For conservation
in captivity, the breeding programme in Thailand is very important.
It should be conducted using the breeding plan developed by
Kasetsart University in Bangkok in order to maintain the genetic
diversity of the species. Since cryo-preservation of sperm is
essential for the captive breeding programme, cryo-preservation
units should be established to provide genetic material when
needed. While aquaculture is very important for food security,
the high value of the species needs to be maintained. Developing
Mekong giant catfish hybrids for aquaculture should be avoided.
Membership of the working group includes the Cambodian, Lao
and Thai fisheries agencies as well as the MRC Fisheries Programme
and the Network of Aquaculture Centres in Asia-Pacifi c (NACA).
Other members include Kasetsart University, WWF, IUCN and Imperial
College, London.
* Dr Naruepon is the director of the Information Technology Centre of the Thai Department of Fisheries and is also chairman of the Mekong Giant Catfish Working Group