Purse seine fisheries work by deploying a net around the outside as well as underneath the tuna school. Along with manta and devil rays, skip-jack tuna love to feed on swarming krill in the summer months which often results in fishing activity overlapping with key mobulid ray feeding areas. These fisheries target whole schools of fish feeding at the surface and are the most common way to catch skip-jack tuna in New Zealand. Tuna purse seine fisheries are also of concern for manta and devil rays. Drift nets and gill nets are particularly treacherous as rays can’t swim backwards and easily get caught in these expansive, open-faced nets. Oceanic manta rays and large devil rays such as spinetails are especially vulnerable to offshore and high seas fisheries. For example, spearfishing is recognised as the most selective method of catching fish whereas bottom trawling is the most destructive and non-selective.īycatch is a global issue that negatively impacts manta and devil rays as well as sea birds, marine mammals, reptiles, invertebrates and innumerable other fish species. The more selective a fishing method, the less impact it has on other marine species and the surrounding environment. Over the last decade there has been a lot of education and awareness around “cleaner” more selective fishing methods that we as consumers can support. Depending on the fishery and fishing method used, the amount of bycatch and the number of species impacted is highly variable. Collaboration, research and education are key to ensuring a sustainable future for the world’s oceans and ocean dependant communities.įisheries bycatch is when non-target species are unintentionally caught in the process of fishing for another species. Manta and devil rays are worth more alive then dead with manta ray tourism alone estimated to be worth $140 million US dollars annually. However, there is still much work to be done to increase protective legislation and help governments and communities to secure viable alternatives such as ecotourism and marine protected areas. Tireless conservation and education efforts have seen massive gains in restricting the international trade of gill plates. These boom and bust industries are highly damaging not only to the environment but also to the people that depend on them. Unfortunately, this highly exploitative health-based marketing has seen a steady rise in consumer demand further fuelled by the product’s high market value. Scientists have yet to find any evidence to support these health claims which at best are considered a pseudo-remedy. Gill plates are marketed to have a range of health benefits including anti-inflammatory, blood circulation and purification properties when consumed. This relatively recent, highly profitable industry is being driven by medicinal markets with the biggest markets being in Hong Kong and China. Gill plates are the fine, sieve-like structures that enable the rays to filter their zooplankton prey out of the water whilst feeding. The primary driver behind this unsustainable fishing pressure is all to do with manta and devil ray gill plates.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |