The guys from Scubazoo recently visited Sri Lanka to film and photograph blue whales. During the trip they took time out to visit fish markets at Mirissa and Negombo, primarily to document the growing trade in manta gill rakers, the next shark fin industry!
Their large size, slow speed and tendency to be near the surface make manta rays easy targets for fishermen but the perceived poor quality of their meat has traditionally meant that until recently they were only threatened by subsistence fishing in remote areas or as bycatch from purse seiners or other netted fisheries. In the last few years however, demand for their dried brachial filaments (gill rakers) as ingredients in chinese traditional medicine has increased fishing pressure worldwide, turning a subsistence fishery into a commercial export industry.
According to the IUCN, targeted fisheries are now present in Philippines, Mexico, Mozambique, Madagascar, India, Sri Lanka, Brazil, Tanzania and Indonesia.
Some quick internet research seems to show that the end product is a powder sold as a means of detoxifying the blood stream with packets claiming to ‘clear away heat and remove toxic material in children after diseases and chickenpox’. Currently there is no scientific data which supports this assertion but of course that does not stop people believing it. While they didn’t have the chance to visit China to observe this, they did see dried gill rakers for sale in a Chinese medicine shop in Kota Kinabalu. On asking they were told that these were to be boiled up in a soup and eaten to treat rashes.
In some good news, recently the Maldives has moved to protect the many manta rays in its waters. A recent study by Chas Anderson, Shiham Adam, Anne-Marie Kitchen-Wheeler and Guy Stevens (2010) estimates that the manta rays in the Maldives bring in over $8.1 million in tourism income to the country every year, giving the population there a rough value of $4,000 per animal per year. An income which is sustainable if the population is left alone. The one time price of catching and killing a ray is tiny in comparison and this gives the Maldives government a strong economic reason to protect what is, essentially, a valuable resource. Of course not every country with manta fisheries has the opportunity or environment to support dive tourism so in these cases alternative livelihoods have to be found for fishermen who’s income is impacted by their loss of trade.
It’s early days in our understanding of the threat that manta rays face right now, with very few facts or figures available. It’s fairly obvious though, from the anecdotal evidence that we’ve seen, that manta rays and their smaller relatives face as uncertain a future as any of the fish in our oceans.
For more on Manta Ray Conservation visit mantarayofhope