Lobster
Rising catches may hide a population crash.
Catches of lobster,
a traditional Christmas treat in much of Europe, are soaring.
But scientists fear that bumper catches will be followed by a
population crash. And efforts to regulate the fishery are being
hindered by a 240-year-old treaty. The North American fisheries
are an important source of imported lobster for European tables.
Fishermen left under- employed by the collapse of other commercial
fisheries in North America have been turning their hands to lobster.
The number of people working in the industry has doubled since 1980.
From an average of 7600 tonnes a year between 1977 and 1986, the
average catch in the northeastern US has now grown to 32 000 tonnes.
Similar increases have taken place in Canada. Fortunately the population
of lobsters has kept pace with the increasing catches. "At first we
thought it was because there were fewer young cod to eat the lobster
larvae," says Steve Murawski of the National Marine Fisheries Service
in Woods Hole, Massachusetts. "But the increase in lobsters started
before the major decline in cod." Now, he says, the chief suspect is
global warming. Lobsters grow faster in warmer water. Unfortunately,
the minimum legal length for lobster destined for the pot is about eight
centimetres. Many lobsters grow this big a year before they become sexually
mature. So they won't reproduce before they are caught. The fishing boom
means few lobster have a chance to grow beyond minimum length. "Three
quarters or more of the catch in some places is not yet mature," says
Murawski. "In some places we are leaving only 2 per cent of the potential
egg laying females." If conditions for the survival of lobster larvae
should become slightly less favourable, the population could crash.
And the slow-maturing lobster would take a long time to recover. "We
had a similar crash in red king crab in the Bering Sea in the 1980s,
and it still hasn't recovered," says Murawski. One answer would be
to increase the minimum legal size, but fishermen object, believing
there would be a smaller market for larger, more expensive lobster.
Signs of overfishing are already emerging on the southwestern coast
of Nova Scotia, where catches in the past couple of years have been
down 30 per cent. The Canadian government has cut the season for
catching lobsters to two months a year to try and preserve stocks.
But in October, in an unrelated fishing dispute, the Canadian supreme
court ruled that under a treaty signed in 1760, the local Mi'kmaq and
Maliseet tribes have unhindered access to the lobster. Native fishermen
immediately began setting their traps, two months before the season opened
for other fishermen. They retaliated by burning buildings and smashing
lobster traps--landing one native boy in hospital. Native leaders have
now declared a voluntary moratorium on lobster fishing in the hope that
new ways of controlling catches will be devised before the next season
opens.
Debora MacKenzie From New Scientist,
