Almost
a dozen species of small cetaceans are on the road towards extinction. An
international group of scientists, including Morigenos, reviewed the current
status of small cetaceans globally. The main reason for the worrisome status of
most of them are the fishing nets that catch and kill hundreds of thousands of
marine mammals each year.
Whales and dolphins lived alongside
human fishers in coastal seas and rivers for thousands of years. But after
World War II, the nets made of cotton and hemp were replaced by cheaper and
more durable synthetic nets. These gill-nets do not require large boats or
expensive equipment, which makes them very attractive to small-scale coastal
fishermen worldwide. But this durability also makes these nets a deadly trap
for many species of whales, dolphins, other marine mammals and sea turtles,
which often do not notice them and cannot escape from them once caught.
For the past 30 years, researchers
and conservationists have been trying to develop nets that the animals could
successfully avoid or break out of, but so far a good solution has not been
found. They also called upon governments of several countries to adopt stricter
measures on the use of such nets, but these measures are difficult to implement
in practice, especially in third world countries. Unfortunately, things are not
simple, since millions of people worldwide depend on small-scale coastal
fishing, especially in poorer countries.
Of course, fishing is not the only
or main threat to all species of whales and dolphins globally. Issues are very
species-, country-, and area-specific. But generally speaking, gill-nets are
the main threat to marine mammals globally, particularly in Africa, Asia and
South America, although Europe is not exempt.
The new review study reports that 11
species of small cetaceans are dangerously close to extinction. The study,
which also involved Tilen Genov from Morigenos, was published in the
international scientific journal Endangered Species Research. The scientists
reviewed information on population sizes, trends and bycatch levels globally.
The river dolphin baiji in China is almost certainly extinct. The vaquita, a
species of porpoise found only in the upper Gulf of California in Mexico,
currently numbers fewer than 19 animals and is literally on the brink of
extinction. The long-term prospects for the Atlantic humpback dolphins, found
along West Africa, are rather grim. The outlook is also rather poor for the
Māui dolphin, found only off New Zealand, as well as for the Taiwanese humpback
dolphin, the Yangtze finless porpoise, three species of Asian river dolphins,
and the Baltic Sea harbour porpoise. In all these cases, gillnets are the
biggest threat.
“Many of these species will vanish
unless gillnets are eliminated”, said Robin Baird, a cetacean expert at
Cascadia Research Collective, USA, who was not involved in the study. But that
will take “political courage,” he stressed, because governments will have to
make unpopular decisions, such as enacting no-fishing conservation zones and
enforcing strict bans. Unfortunately, he said, at this point that is the only
way “to keep these species and populations from going extinct.”
Tilen Genov from Morigenos said:
“Slovenia, fortunately, isn’t part of this statistic. Bycatch of dolphins in
fishing nets does occur here, but appears relatively rare. When it does happen,
the fishermen typically contact us themselves. We have a very good collaboration
with them. We also currently have no indication of any dolphin population
decline.” He added: “Of course, as researchers we do not only care about
dolphins, as we are well aware that the right solutions need to be good for
people and endangered species alike. But this will take a lot of effort,
collaboration and innovation.”
The
study is freely available at the following link: https://www.int-res.com/abstracts/esr/v40/p285-296/
