Fish mistaking plastic debris in ocean for food, study
finds. Behavioural evidence suggests marine organisms are not just ingesting
microplastics by accident but actively seeking them out as food!
Fish may be actively seeking out plastic debris in the
oceans as the tiny pieces appear to smell similar to their natural prey, new
research suggests. The fish confuse plastic for an edible substance because
microplastics in the oceans pick up a covering of biological material, such as
algae, that mimics the smell of food, according to the study published in
the journal Proceedings of the Royal Society B.
Scientists presented schools of wild-caught anchovies
with plastic debris taken from the oceans, and with clean pieces of plastic
that had never been in the ocean. The anchovies responded to the odours of the
ocean debris in the same way as they do to the odours of the food they seek.
The scientists said this was the first behavioural
evidence that the chemical signature of plastic debris was attractive to a
marine organism, and reinforces other work suggesting the odour could be
The finding demonstrates an additional danger of
plastic in the oceans, as it suggests that fish are not just ingesting the tiny
pieces by accident, but actively seeking them out.
Matthew Savoca, of the National Oceanic and
Atmospheric Administration and lead author of the study, claims: “When plastic
floats at sea its surface gets colonised by algae within days or weeks, a
process known as biofouling. Previous research has shown that this algae produces
and emits DMS, an algal based compound that certain marine animals use to find
food. The research shows plastic may be more deceptive to fish than previously
thought. If plastic both looks and smells like food, it is more difficult for
animals like fish to distinguish it as not food.”
Plastic debris in the oceans, ranging from the
microscopic to large visible pieces, is recognised as a growing problem as it
does not readily degrade and hundreds of thousands of tonnes are dumped in the
sea annually. Larger pieces have been found in the intestines of whales
and seabirds, where they are thought to be potentially fatal, while the
smallest pieces have been detected in the guts of even juvenile fish and
molluscs. Numerous species of fish eaten by humans have been found
to contain plastic, and the effect of eating these on human health is
Efforts to reduce marine plastic have so far had little effect: microbeads widely used in cosmetics and other products have been banned in the US, the UK and other countries, but they only solve part of the problem, which is mainly caused by dumping of plastic rubbish. There could be more plastic than fish in the sea by 2050, campaigners have warned.
Scientists have struggled to understand exactly how
the massive increase in plastics may be affecting the behaviour of fish and
marine ecosystems, and how to contain the problem.
A previous paper published in the journal Science that
alleged juvenile fish were attracted to microplastics “like teenagers after
junk food” was withdrawn earlier this year after
controversy. The scientists involved in that paper, who have no relation to the
authors of today’s study, were suspected of having exaggerated their data or
failed to carry out the purported experiments properly. The new paper did not
draw on that publication.
Guardian, August 2017)
The Croatian group of participants to the “Save the Wave” project meeting, held from 13th to 19th September on Madeira island in Portugal, witnessed a sea turtle struggling in vain to dive into the ocean because of the plastic swallowed in its stomach. The sad event happened during a dolphin watch tour organized as part of the project activities of the 3 national groups from Croatia, Portugal and Greece under the frame of the Erasmus+ Youth Exchanges program.
The spectacle became even more dramatic when the Croatian young people realized that bureaucracy and lack of directions in emergency cases like that, are a serious obstacle obviously not only in Madeira, but in many other countries as well.
The objectives of that second and last meeting of the
3 national groups were to discover how much effort each participating country
makes to fight plastic pollution, and which policies they develop and implement
for the preservation of marine.
The three groups have also explored and researched, under the coordination of the Croatian organization “Udruga Prizma” and the support of the partner organizations “Teatro Metaphora” in Portugal and “Dione” local development centre in Greece, about their national poets, painters, sculptors, artists, who are deeply connected with nature and sea.
The conclusion of that project meeting was that we, like the Fall and the Drop, are all part of the same chain…