Whales - from BBC website

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Whale stranding cases 'increase'

 

Whale, dolphin and porpoise strandings have doubled in the UK over

the last 10 years to 782, according to a new study.

The Whale and Dolphin Stranding Scheme at the Natural History Museum

blames an increase in fishing activity, which it says leads to

more " by-catch " .

This can occur when dolphins or whales chase fish into giant nets,

where they then get entangled in the gear.

The government, which part-funded the research, hopes to reduce by-

catch by restricting certain types of trawling.

The Department for Environment, Food and Rural Affairs (Defra) is

also testing new designs of " dolphin friendly " nets, which either

have an escape hatch or acoustic devices to keep the mammals away.

" I have always maintained that we must take firm action to reduce

injury and death to dolphins from this fishery, " said minister Ben

Bradshaw.

Pair trawling

Strandings of cetaceans (the group that includes whales, dolphins and

porpoises) have increased from 360 in 1994 to 782 in 2004, the report

finds.

Since only a fraction of dead whales and dolphins will eventually

arrive on beaches to be counted, the actual number of cetacean deaths

is almost certainly much higher.

" We believe that the numbers of animals we see stranded probably

represents 10% of what is being killed out there, " Richard Sabin, of

the Natural History Museum, London, told the BBC News website.

Marine strandings can occur for all sorts of reasons - many of them

nothing to do with human activity.

" Some live strandings are natural events, " said Mark Simmonds, of the

Whale and Dolphin Conservation Society.

" The animals may make navigational errors; then again, they are

highly dependent on one another, so if one becomes sick or injured

the others may stay with it, even at risk to themselves. "

However, natural whale strandings are likely to stay constant - so

something else is probably going on around UK waters.

Richard Sabin believes the soaring numbers of cetacean deaths can be

attributed to an increase in a certain method of sea bass fishing,

known as pair-trawling, where great nets are suspended between two

vessels.

Pair-trawling generally occurs between the months of November and

April and, sure enough, the greatest numbers of dolphin strandings

occur at the same time.

" If you look at the numbers of common dolphins stranded over the

winter months, they increase as a direct correlation, " said Dr

Sabin. " By-catch is completely indiscriminate. It takes the young and

the old - everyone gets involved. "

Written in death

Sometimes, signs of their miserable death can be found on their

bodies during post-mortem.

" They are trapped underwater in the nets, and they react by closing

their blow holes, " said Dr Simmonds. " They fight to get free, and

this can last for many minutes; and you can read the signs of this

struggle on their bodies - cuts on their snouts, broken teeth,

damaged fins. "

Last September, Defra announced new measures to help reduce death and

injury to dolphins by pair-trawling techniques used in the South West

of England.

These measures include banning pair-trawling out to 20km (12 miles),

and introducing a licensing system for UK vessels within the 20-320km

(12-200 miles) zone.

However, Richard Sabin believes that other factors, such as military

sonar, may be driving some of the animals ashore.

" We have seen animals that show signs of decompression sickness,

which can be linked to sonar, " he told the BBC News website.

Mark Simmonds agreed that sonar could play a part. He said: " It is

possible for live animals to be chased, as it were, onto land by man-

made noise in the sea. "

But it is far more difficult to directly blame strandings on sonar

because military exercises tend to be conducted in secret.

Richard Sabin is certain, however, that whatever the cause, too many

cetaceans are dying.

" Everyone who is involved in marine conservation agrees that no

population can sustain the level of die-off that we've seen, with the

common dolphin particularly, in the last five years. "

He wants the public to help future monitoring of dolphin deaths. " The

work that is being done by people around the UK is incredibly

important, " he said. " What we need is another 10 years of exactly the

same sort of effort. "

If you find a dead stranded whale or dolphin contact:

• England: 020 794 25 155 (The Natural History Museum)

• Scotland: 01463 243 030 (Scottish Agricultural College)

• Wales: 01348 875 000 (Marine Environmental Monitoring)

If you find a live stranded whale or dolphin, contact your local

RSPCA.