Dolphins and the Tuna Industry
Dolphins and the Tuna Industry

Author: National Research Council

Publisher: National Academies Press

Published: 1992-02-01

Total Pages: 191

ISBN-13: 0309047358

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This book presents key conclusions about the controversial killing of thousands of dolphins each year during tuna fishing in the eastern tropical Pacific. Dolphins drown in nets that are set to catch yellowfin tuna, which tend to swim beneath dolphin herds. After 20 years of intense debate among environmentalists, the tuna industry, and policymakers, this fatal by-product of tuna fishing remains a high-profile public issue. Dolphins and the Tuna Industry provides a neutral examination of the scientific and technical questions at the core of the problem. Recommendations for solutions are offered in two areas: developing new techniques that promise to reduce dolphin mortality with the existing purse-seine method of tuna fishing, and developing entirely new methods of finding tuna that are not swimming with dolphins. Dolphins and the Tuna Industry provides a comprehensive, highly readable overview of the dolphin-tuna controversy, useful to experts and newcomers to the issue. It explores the processes of tuna fishing and dolphin mortality, the status of the tuna industry, and the significant progress made in reducing dolphin mortality through modifications in fishing practice. The volume includes: An overview of U.S. laws and policies relating to tuna and dolphins. An illustrated look at how tuna fishing crews use their equipment, focusing on the purse seine, which is the method most economical to the industry but most deadly to the dolphins. An overview of what is known about tuna and dolphin populations and the remarkable bond between them. A step-by-step description of the fishing process and efforts to let dolphins escape from the nets. An analysis of possible approaches to reducing dolphin kill, including more stringent regulatory approaches and incentives for the tuna industry. This book will be indispensible to environmental and animal protection groups, tuna fishing crews and processors, companies that market tuna products, policymakers, regulators, and concerned individuals.

Caught in the Net
Caught in the Net

Author: Alessandro Bonanno

Publisher:

Published: 1996

Total Pages: 314

ISBN-13:

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A documentary history that studies the series of laws passed by the US Congress to establish the federal immigration and naturalization policies which have been put into effect since the founding of the nation--legislation which has been designed increasingly to restrict and curtail immigration, and which has been particularly harsh on Asian immigrants since its inception. Complete chapters are devoted to each major piece of legislation from the Reconstruction era to the Immigration Act of 1965. Documents attached to the end of each essay treat particular topics related to it. Annotation copyright by Book News, Inc., Portland, OR

The Effects of Seasonal Variations, El Niño-Southern Oscillation, and Climate Change on the Tuna-dolphin Association
The Effects of Seasonal Variations, El Niño-Southern Oscillation, and Climate Change on the Tuna-dolphin Association

Author: Caitlynn Amber Birch

Publisher:

Published: 2019

Total Pages: 102

ISBN-13:

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Tuna and dolphins swim together in the waters of the eastern tropical Pacific, and this association has long benefitted tuna fishermen and intrigued scientists. Although the tuna-dolphin association is often referred to as a "mystery," much is known about the association. Yellowfin tuna are primarily caught with spotted dolphins and, to a lesser extent, spinner dolphins; historically the spotted dolphin has borne the brunt of the bycatch mortality. The tuna-dolphin association is thought to be a product of the distinct oceanography of the ETP: a shallow mixed layer, a thick oxygen minimum zone, and warm surface waters. As the mixed layer deepens, the association begins to break down: first with spinner dolphins, then with spotted dolphins. Important ecological and management questions remain. What are the effects of season, El Niño Southern Oscillation (ENSO) cycles, and long-term climate change on the association? What will be the future effects on the association with the continued influence of climate change? And how will these changes affect the fishery and dolphin mortality? We used the IATTC observer data from 1992-2017 for pure herds of spotted dolphins and spinner dolphins (n=201,988 sightings), oceanographic data from global data assimilative models (0.25ox 0.25o resolution), GIS and explanatory and predictive models (R-based Boosted Regression Trees) to understand the tuna-dolphin distribution and dynamics in the ETP. The mixed layer depth and chlorophyll were the most significant factors, and sea surface temperature, temperature at depth, and sea surface height were also important factors. The spatial distribution of the association expanded and contracted with season and ENSO events, overlaid on a long-term expansion caused by climate change. The conditions that promote the tuna-dolphin association are intensifying and the management implications are already apparent: sets on pure spinner dolphin herds have increased, and spinner dolphins have replaced spotted dolphins as the leading component of incidental dolphin mortality.