November 4, 2010

Loggerhead Turtles Face Debris Threat In Adriatic Sea

According to researchers studying the impacts of debris on marine life, one in three loggerhead turtles in the Adriatic Sea has plastic in its intestine.

The shallow waters in the Adriatic Sea are an important place for the turtles to feed as they develop into adults.

However, the seafloor there is one of the most polluted in Europe.

Researchers studied the bodies of dead sea turtles that had been stranded or accidentally caught by fishing vessels.

The team found that animals ranging from invertebrates to large mammals consume plastic waste and are concerned that it could damage their health.

Only a few grams of debris can be fatal for a turtle if it obstructs the gut, BBC News reports.

Researchers from the University of Zagreb said that over a third of the 54 turtles they examined had ingested marine debris of some kind such as plastic bags, wrapping foils, ropes, polystyrene foam and fishing line.

One turtle consumed 15 pieces of plastic, which almost completely filled its stomach.  The team said it was enough plastic to "probably cause the death of this individual."

Plastic can weaken the turtles by taking up space in the gut, which would otherwise digest food.

The shallow waters of the northern Adriatic are one of the most important feeding grounds for loggerhead turtles in the Mediterranean. 

The southern Adriatic is also important for the turtles' development into ocean-going animals.

"It is important to know more about the Adriatic Sea in order to help loggerhead turtles across the whole Mediterranean." Romana Gracan, one of the researchers involved in the study, told BBC.

"The water temperature here suits them and because it is shallow they have the opportunity to feed on benthic [sea-floor] animals."

The sea floor is among the most littered sea floors along European coasts, after the northwestern Mediterranean and the Celtic Sea.

The waste comes from the dense population of four million people who live along the coast, along with the 18 million summer tourists.

The sea is small and largely cut off from the rest of the Mediterranean, only joined to the Ionian Sea by the 43 mile-wide Strait of Otranto.

Loggerhead turtles are omnivorous feeders that feed at a variety of different depths.

The researchers say their study is the first to address the problems caused by solid debris in the Adriatic Sea.

Chemical pollution in the Adriatic has been studied for over 30 years and is already central to marine conservation in the Mediterranean.

The team hopes they have shown that the turtles are particularly vulnerable to plastic debris and that more will be done in order to reduce it.

"Loggerheads are opportunistic feeders which will eat almost anything that is in front of them and plastic stays around for a very long time in the sea," Gracan told BBC.

"In the future we must think more carefully what we put in the sea."

The study was published in the journal Marine Pollution Bulletin.


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