Sea turtles

Legal harvest tops 42,000 a year

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Green sea turtle (Chelonia mydas)

A new study from the University of Exeter has comprehensively reviewed the number of sea turtles currently taken within the law and assessed how the effects of this fishery compare to those of other global threats to these magnificent animals.

All marine turtles are currently listed on the IUCN Red List of Threatened Species.

Frances Humber a PhD student at the University of Exeter, who led the research, said: “This is the first study to comprehensively review the legal take of turtles in recent years, and allows us to assess the relative fisheries threats to this group of species. Despite increased national and international protection of marine turtles, direct legal take remains a major source of mortality. However, it is likely that a fraction of current marine turtle mortality take is legal, with greater threats from illegal fisheries and bycatch.”

Large scale commercial taking of turtles has gone on all over the world for centuries, with global capture peaking at over 17,000 tons in the late 1960s. During the peak of Mexico’s sea turtle exploitation in 1968 it is estimated that the national take was over 380,000 turtles.

Increased conservation awareness at an international scale has led to greater protection of sea turtles, with 178 countries now signed up to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) restricting the international trade of turtle products.

The direct take of turtles has continued legally in many regions and countries, often for traditional coastal communities to support themselves or small-scale fisheries supplying local markets with meat, and sometimes shell. The fisheries are an important source of finance, protein and cultural identity, but information can be scarce on their status   – despite often being listed as one of the major threats to turtle populations.

The researchers collated data for all sea turtles from over 500 publications and 150 in-country experts.

They estimate that currently more than 42,000 sea turtles are caught each year legally, of which over 80% are green turtles (see picture above). Legal fisheries are concentrated in the wider Caribbean region and in the Indo-Pacific region, with Papua New Guinea, Nicaragua and Australia together accounting for almost three quarters of the total.

Findings of the studhy suggest that since the 1980s more than 2 million turtles have been caught, although current catch rates are less than 60% of those in the 1980s.

But the accidental trapping of turtles in commercial fishing nets is thought to be a far higher cause of death, likely running into hundreds of thousands of marine turtles each year.

Illegal fishing also continues to be a major cause of mortality, with the researchers estimating a minimum of 65,000 turtles taken from Mexico alone since the year 2000. The scale of global illegal capture is likely to be severely underreported due to the difficulties collecting information on such an activity.

Dr Annette Broderick, also of the University of Exeter, added: “We were surprised to find that there are 42 countries with no legislation in place that prohibits the harvest of marine turtles, although for many of these countries these harvests provide important sources of protein or income. It is however important to ensure that these fisheries are operating at a sustainable level.”

The article presenting this data, ‘So Excellent a Fishe: A global overview of legal marine turtle fisheries’ is published in the journal Diversity and Distributions.

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