Cetacean bycatch in Indian Ocean tuna gillnet fisheries

Pelagic gillnet (driftnet) fisheries account for some 34% of Indian Ocean tuna catches. We combined published results from 10 bycatch sampling programmes (1981−2016) in Australia, Sri Lanka, India and Pakistan to estimate bycatch rates for cetaceans across all Indian Ocean tuna gillnet fisheries. Estimated cetacean bycatch peaked at almost 100 000 ind. yr−1 during 2004−2006, but has declined by over 15% since then, despite an increase in tuna gillnet fishing effort. These fisheries caught an estimated cumulative total of 4.1 million small cetaceans between 1950 and 2018. These bycatch estimates take little or no account of cetaceans caught by gillnet but not landed, of delayed mortality or sub-lethal impacts on cetaceans (especially whales) that escape from gillnets, of mortality associated with ghost nets, of harpoon catches made from gillnetters, or of mortality from other tuna fisheries. Total cetacean mortality from Indian Ocean tuna fisheries may therefore be substantially higher than estimated here. Declining cetacean bycatch rates suggest that such levels of mortality are not sustainable. Indeed, mean small cetacean abundance may currently be 13% of pre-fishery levels. None of these estimates are precise, but they do demonstrate the likely order of magnitude of the issue. Countries with the largest current gillnet catches of tuna, and thus the ones likely to have the largest cetacean bycatch are (in order): Iran, Indonesia, India, Sri Lanka, Pakistan, Oman, Yemen, UAE and Tanzania. These 9 countries together may account for roughly 96% of all cetacean bycatch from tuna gillnet fisheries across the Indian Ocean

Cetacean bycatch in Indian Ocean tuna gillnet fisheries

Pelagic gillnet (driftnet) fisheries account for some 34% of Indian Ocean tuna catches. We combined published results from 10 bycatch sampling programmes (1981−2016) in Australia, Sri Lanka, India and Pakistan to estimate bycatch rates for cetaceans across all Indian Ocean tuna gillnet fisheries. Estimated cetacean bycatch peaked at almost 100 000 ind. yr−1 during 2004−2006, but has declined by over 15% since then, despite an increase in tuna gillnet fishing effort. These fisheries caught an estimated cumulative total of 4.1 million small cetaceans between 1950 and 2018. These bycatch estimates take little or no account of cetaceans caught by gillnet but not landed, of delayed mortality or sub-lethal impacts on cetaceans (especially whales) that escape from gillnets, of mortality associated with ghost nets, of harpoon catches made from gillnetters, or of mortality from other tuna fisheries. Total cetacean mortality from Indian Ocean tuna fisheries may therefore be substantially higher than estimated here. Declining cetacean bycatch rates suggest that such levels of mortality are not sustainable. Indeed, mean small cetacean abundance may currently be 13% of pre-fishery levels. None of these estimates are precise, but they do demonstrate the likely order of magnitude of the issue. Countries with the largest current gillnet catches of tuna, and thus the ones likely to have the largest cetacean bycatch are (in order): Iran, Indonesia, India, Sri Lanka, Pakistan, Oman, Yemen, UAE and Tanzania. These 9 countries together may account for roughly 96% of all cetacean bycatch from tuna gillnet fisheries across the Indian Ocean

Tourist satisfaction and expenditures in a reef-adjoining dolphin watching industry in Lovina, Bali Indonesia

This chapter focuses on tourist experience and economic benefits of the reef-adjoining dolphin watching industry in Lovina, Bali Indonesia in 2013. Tourist satisfaction was generally low, the tourists disliked the inconsiderate driving behaviours of the boatmen and satisfied tourists were more likely to rejoin the trip or recommend the trip to others. The industry's total direct expenditures were ~USD 8.7 million p.a., with ~ USD 72,800 p.a. financial spill-over to the local snorkelling industry. Without the dolphins, Lovina might lose ~27% of the total direct expenditures (~ 11% to adjacent reef sites). Dolphin conservation combined with local reef tourism should be made priority to sustain local income in the future

Using multiple indicators to evaluate the sustainability of dolphin-based wildlife tourism in rural India

Assessing wildlife tourism sustainability in developing countries is crucial, but few studies analyse the sustainability of dolphin-based wildlife tourism in this context. We measure multiple indicators within the human dimensions of wildlife tourism, including tourist visitation numbers, satisfaction, preferences, perceptions, background and specialisation, to ascertain the extent to which the dolphin-watching industry at Chilika Lagoon, in rural India might be considered sustainable. Our methods included participant observation, tourist surveys, and the use of secondary data on visitation over 10 years. We found that the growth rate of tourist visitation over 10 years was beginning to decline. Tourists were mostly inexperienced, and dissatisfied with their dolphin-watching experience. Tourist preferences and perceptions showed useful insights and shortcomings in the way in which the industry was being conducted and managed, and reflected the expectations of non-specialist visitors. Our study highlights drawbacks in the way that wildlife tourism is managed in a rural, developing world context, which draws the sustainability of the dolphin-watching industry in Chilika into question. Future development of an early warning system that addresses combined governance or managerial, social, economic and ecological indicators, and an integrated management plan for conservation and wildlife tourism could contribute to the sustainable management of such industries

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Not AvailablePelagic gillnet (driftnet) fisheries account for some 34% of Indian Ocean tuna catches. We combined published results from 10 bycatch sampling programmes (1981−2016) in Australia, Sri Lanka, India and Pakistan to estimate bycatch rates for cetaceans across all Indian Ocean tuna gillnet fisheries. Estimated cetacean bycatch peaked at almost 100 000 ind. yr−1 during 2004−2006, but has declined by over 15% since then, despite an increase in tuna gillnet fishing effort. These fisheries caught an estimated cumulative total of 4.1 million small cetaceans between 1950 and 2018. These bycatch estimates take little or no account of cetaceans caught by gillnet but not landed, of delayed mortality or sub-lethal impacts on cetaceans (especially whales) that escape from gillnets, of mortality associated with ghost nets, of harpoon catches made from gillnetters, or of mortality from other tuna fisheries. Total cetacean mortality from Indian Ocean tuna fisheries may therefore be substantially higher than estimated here. Declining cetacean bycatch rates suggest that such levels of mortality are not sustainable. Indeed, mean small cetacean abundance may currently be 13% of pre-fishery levels. None of these estimates are precise, but they do demonstrate the likely order of magnitude of the issue. Countries with the largest current gillnet catches of tuna, and thus the ones likely to have the largest cetacean bycatch are (in order): Iran, Indonesia, India, Sri Lanka, Pakistan, Oman, Yemen, UAE and Tanzania. These 9 countries together may account for roughly 96% of all cetacean bycatch from tuna gillnet fisheries across the Indian Ocean.Not Availabl

A treasure from the past: Former sperm whale distribution in Indonesian waters unveiled using distribution models and historical whaling data

This study is the first in Indonesia to assess historical sperm whale (Physeter macrocephalus ) seasonal distributions by combining historical whaling data with environmental factors associated with sperm whale habitat preferences. As current records of whale occurrence covering the whole of Indonesian waters are incomplete, we used historical whaling data summarized by Charles Haskins Townsend in 1935 to model its potential distribution for each season