Simple changes could save Swordfish

Simple changes to fishing gear and fishing practices could help
swordfish populations in the Mediterranean recover from intensive
fishing. Adult swordfish grow to lengths of more than 4 metres and can
weigh up to half a tonne. But in the past two decades, the average
weight of those caught in the Mediterranean has dropped from 48
kilograms to just 10. Half do not meet the minimum length requirement of
125 centimetres. But many restaurateurs prefer smaller fish because they
are a better size for the plate. "In the past, when fishermen caught
juveniles, they just threw them back. But now the tourist market has a
strong demand for them," says biologist Ricardo Aguilar of Oceana, an
environmental pressure group based in Madrid, Spain. The result is that
many fish are being caught before they have a chance to breed. The
extent of the problem is unclear because some Mediterranean countries,
such as Israel, Libya and Egypt, do not provide any data on catches.

Larger hooks

Last week Oceana proposed a raft of measures for reducing catches of
juvenile swordfish and unwanted by-catches such as turtles. Besides
traditional measures such as smaller quotas, closed seasons and
protected zones, the organisation also wants authorities to allow the
use of larger hooks and encourage the use of G-shaped hooks rather than
J-shaped ones. There is some evidence that G-shaped hooks are less
likely to snare sea turtles, which are killed in their thousands by
swordfish long lines every year. Studies should also be carried out to
find out if setting long lines deeper in the water, below the
thermocline, reduces catches of juveniles, Aguila says. "These are the
kinds of measures which could really help the swordfish population in
the Mediterranean recover," says Ellen Pikitch of the Pew Institute at
the University of Miami, who worked on the North Atlantic swordfish
recovery programme, which is showing signs of success. Mediterranean
swordfish are even better positioned for a comeback, she adds, because
they grow and mature faster than their cooler-water cousins. By the age
of 5, a female can produce up to 29 million eggs. Given the right
management, they should be able to bounce back in the next couple of
years, even without a drastic reduction in quotas.