A field effort to capture critically endangered vaquitas Phocoena sinus for protection from entanglement in illegal gillnets

Abstract

In 2017 an emergency field effort was undertaken in an attempt to prevent the extinction of the world's most endangered marine mammal, the vaquita Phocoena sinus. The rescue effort involved 90 experts from 9 countries and cost US$ 5 million. Following a long decline due to entanglement in legal gillnet fisheries, the vaquita population had fallen from more than 200 to fewer than 30 individuals from 2008 to 2016, due to entanglement in an illegal gillnet fishery that supplies swim bladders of the endangered totoaba Totoaba macdonaldi to Chinese black markets. An emergency ban of gillnets and increased enforcement failed to slow the decline, triggering an emergency effort to catch vaquitas and place them under protection in captivity. Two animals were targeted and captured using light gill nets; a juvenile was released 4 h later because it appeared stressed, and an adult female died of capture myopathy. The program was suspended because of the risk of additional mortalities to the population. The lack of success in capturing vaquitas for temporary protection emphasizes the need to improve our understanding of the effects of chase, capture, handling and enclosure on cetaceans, and to consider intervention before populations reach critically low levels, when there is sufficient time to use phased, precautionary approaches. Furthermore, conservation approaches focused on single species must be integrated into broader efforts to conserve ecosystems and involve the human communities that depend on them.

Likely annual calving in the vaquita, Phocoena sinus: A new hope?

“…On 18 October 2017 a group of three vaquitas was sighted off San Felipe, Baja California Norte, Mexico, as part of an effort to capture vaquitas and bring them into human care, (Rojas-Bracho et al 2019). Two of the vaquitas were photographed together at 1037 (local time) ( Fig.…”

Vaquita Face Extinction from Bycatch. Comment on Manjarrez-Bringas, N. et al., Lessons for Sustainable Development: Marine Mammal Conservation Policies and Its Social and Economic Effects. Sustainability 2018, 10, 2185

“…We are convinced by the research of the past 20 years, e.g., [2][3][4][5][6][7] that vaquita face extinction because they drown in gillnets. Manjarrez-Bringas et al [1] fail to discuss the extensive evidence for the effects and extent of bycatch, their own data on the effects of fishing restrictions on GSC fishers are not adequate, their logic is faulty, and they present no direct evidence to support a causal link between Colorado River flow and the size of the vaquita population.…”

“…Prices for totoaba swim bladders are a powerful economic incentive for illegal gillnet fishing in the UGC. Illegal gillnet fishing in the UGC is a major cause of vaquita mortality [4,29,30]. Tragically, both totoaba and vaquita are endangered species.…”

“…We object to any suggestion that our research supports Manjarrez-Bringas et al's [1] conclusion linking the decline in the Colorado River's flow to the dramatic decline in the population of vaquita. Given what is known about the biology of vaquita [2][3][4][5][6][7] and the documented environmental changes resulting from the lack of river flow [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], we conclude that vaquita face extinction because of bycatch, not the lack of river flow.…”

Health Assessments of Common Bottlenose Dolphins (Tursiops truncatus): Past, Present, and Potential Conservation Applications

“…Increased international collaboration is essential for mitigating conservation crises and aiming to reduce the number of marine mammals becoming extinct such as the recent loss of the Yangtze River dolphin, the baiji (Lipotes vexillifer), or the high-risk Mediterranean monk seal (Monachus monachus) and vaquita porpoise (Phocoena sinus) (4,174). Knowledge of capture techniques gained from dolphin health assessments in the U.S. has been applied to alternative species conservation approaches, such as with the vaquita, in an effort to temporarily remove animals from a dangerous habitat and relocate them to a protected environment (175). Marine mammal stranding networks exist world-wide with varying capacity dependent on funding, degree of public interest, number of strandings per year, facilities available, and the extent of inter-agency cooperation (176).…”