Small-scale fisheries a big threat to rays

Manta and devil rays, collectively known as mobulids, are large cartilaginous fish known for their broad, wing-like pectoral fins, which help them glide through the water. They often feed on zooplankton and small crustaceans and fish in shallow coastal waters, making them vulnerable to entanglement in fishing nets. Roughly 259,000 mobulids are killed each year in fisheries, globally. Five countries — India, Indonesia, Sri Lanka, Myanmar and Peru — account for 87% of these deaths, which are mostly attributed to small-scale fisheries. India is the highest contributor, accounting for 28.2% deaths. Limited catch data and inadequate understanding of the impacts of small-scale fisheries make it difficult to assess the status of these species. Increasing fishing pressure puts several ray species at risk of population collapse. To address this gap, a group of researchers tracked mobulid bycatch from fishing boats in Thoothukudi, Tamil Nadu, between 2013 and 2023. Their study, published in Conservation Science and Practice, found evidence of declining populations of four species — the spinetail devil ray (Mobula mobular), the sicklefin devil ray (Mobula tarapacana), the oceanic manta ray (Mobula birostris), and the bentfin devil ray (Mobula thurstoni). The study notes that these population declines occurred alongside increasing fishing pressure, suggesting overfishing as the likely cause. “Counting the number of mobula rays caught is always confusing,” said Divya Karnad, a senior lecturer at the University of Exeter and an author of the study. Because the research team wanted to track real changes in the population, they divided the catch…This article was originally published on Mongabay