Sharks: Increasing losses despite protective measures

The fight against so-called finning – the extraction of fins for the delicatessen market – is apparently not enough to effectively limit the pressure on shark stocks. © Alessandro De Maddalena/iStock

The hope of relieving the pressure on shark populations threatened worldwide has not yet been fulfilled: despite national and international protection efforts, fishing has led to a further increase in losses, according to a study. Accordingly, the number of sharks killed annually has increased from 76 million to over 80 million since 2012. Above all, the study shows that the extensive regulations to combat the extraction of shark fins have not provided effective relief. However, more targeted protective measures could be successful, the researchers report.

The oceans are increasingly losing their ecologically important top predators: Over the past ten years, marine biologists have repeatedly warned about the threat posed by fishing to shark populations. The majority of the animals killed are not actually the primary targets: the sharks end up in the net and on the hook alongside tuna and the like. However, it is often welcome bycatch, as shark fins are sought after as a delicacy, especially in Asia. Instead of releasing them again, the sharks' fins are often cut off and the rest of their bodies are thrown overboard.

The denunciation of this so-called finning and the reports about the threat to sharks have had a positive effect over the past ten years: governments around the world have passed a variety of regulations aimed at reducing shark fishing and finning. However, so far there has been no global assessment of the extent to which these measures have actually limited losses. An international team of scientists has now addressed this question. The researchers have compiled extensive information from 150 fishing countries. They examined developments in shark fishing from 2012 to 2019 - a time when many new regulations were implemented. They also conducted interviews with fisheries experts to better assess current trends in shark finning and fishing practices.

What did the measures achieve?

As the researchers report, their data evaluations led to a sobering result. “We show that widespread legislation has been partially successful in restricting shark finning, but has failed to reduce mortality overall,” summarizes first author Boris Worm from Dalhousie University in Nova Scotia. Specifically, the evaluations showed that the losses caused by fishing increased from 76 million to at least 80 million sharks per year during the study period. The researchers report that more than 30 percent of the sharks killed were shark species that are already considered to be at risk of extinction.

In detail it became clear that the new legislation to prevent shark finning only had a positive impact on deep-sea fishing. The data analyzes suggest that shark losses fell by around seven percent, particularly in the Atlantic and Western Pacific. But overall, the increase in bycatch is much more significant in more intensive fishing in coastal areas. The bottom line is that the new regulations have had little positive impact - perhaps even the opposite: some have encouraged more widespread use of sharks, creating new incentives for fishing and creating new markets for shark products, the researchers say.

Problematic developments and glimmers of hope

Co-author Leonardo Feitosa from the University of California at Santa Barbara (UC Santa Barbara) said: “We found that demand for shark fins fell while demand for shark meat increased, with Brazil and Italy being the main consumers. Because shark meat is a relatively inexpensive substitute for other types of fish, there is also significant mislabeling that leads to some consumers eating shark meat without their knowledge,” says Feitosa.

In addition to the sobering results and the problematic developments, the study also gives reason for hope: the researchers were able to show that certain measures have actually led to a reduction in losses in shark populations. However, this obviously requires stricter bans, protection zones and controls, as the successful examples show. “More specific measures to combat shark losses – such as banning fishing in certain areas or requiring fishermen to release endangered species they accidentally catch – can help protect more sharks,” says Echelle Burns from the University of California in Santa Barbara.

Despite the lack of overall success, efforts to protect sharks so far also offer hope, says co-author Laurenne Schiller of Carleton University in Ottawa: “Governments and some fishing companies around the world have pushed to eliminate finning, often in response to public concerns Pressure. The challenge now is to build on this momentum and take more effective measures to reduce shark killings overall,” said Schiller.

Source: University of California – Santa Barbara, specialist article: Science, doi: 10.1126/science.adf8984

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