Dolphins and the tuna industry / Committee on Reducing Porpoise Mortality from Tuna Fishing, Board on Biology, Board on Environmental Studies and Toxicology, Commission on Life Sciences, National Research Council.

Format:

Book

Author/Creator:

National Research Council (U.S.). Committee on Reducing Porpoise Mortality from Tuna Fishing.

Language:

English

Subjects (All):

Tuna fisheries--Environmental aspects.

Tuna fisheries.

Dolphins--Mortality.

Dolphins.

Tuna industry--Environmental aspects.

Tuna industry.

Physical Description:

1 online resource (xii, 176 pages) : illustrations

Edition:

1st ed.

Place of Publication:

Washington, D.C. : National Academy Press, 1992.

Language Note:

English

Summary:

Providing a comprehensive overview of the dolphin-tuna controversy, this book explores the processes of tuna fishing and dolphin mortality, the status of the tuna industry, and the progress made in reducing dolphin mortality through modifications in fishing practice. It is useful for animal protection groups, policymakers, regulators, and others.

Contents:

Dolphins and the Tuna Industry

Copyright

Preface

Contents

Executive Summary

INTRODUCTION

THE PROBLEM

THE CURRENT FISHERY

DOLPHIN MORTALITY ASSOCIATED WITH THE TUNA FISHERY

U.S. TUNA AND MARINE MAMMAL POLICY AND ECONOMICS

FISHING GEAR

BEHAVIOR OF TUNA AND DOLPHINS IN THE ETP

FACTORS AFFECTING DOLPHIN MORTALITY

ESTIMATES OF DOLPHIN ABUNDANCE

TECHNIQUES FOR REDUCING DOLPHIN MORTALITY

RECOMMENDATIONS

Recommendations Concerning the ETP Tuna-Dolphin Fishery

Recommendations for Research on Harvesting Tuna Not in Association with Dolphins

1 Introduction

BACKGROUND ON REDUCING DOLPHIN MORTALITY FROM TUNA FISHING

The Current Tuna Fishery and Its Development

Dolphin Mortality Associated with the Tuna Fishery

Reducing Dolphin Mortality

THE COMMITTEE'S STUDY

2 Some Policy and Economic Considerations

U.S. TUNA AND MARINE MAMMAL POLICY

U.S. Tuna Policy

IATTC and Tuna Conventions Act

Fishery Conservation and Management Act

U.S. Marine Mammal Policy

Marine Mammal Protection Act

International Policy Context

ECONOMIC CONSIDERATIONS

Recent Tuna-Harvesting Operations

Historical Perspective

Tuna-Processing Operations

Industrywide Trends

The Effects of Recent Changes

3 Background on Fishing Gear

PURSE SEINES

The Backdown Process

OTHER FISHING METHODS

Longline Fishing

Log Fishing

School Fishing

4 Biology and Ecology of Yellowfin Tuna

DISTRIBUTION AND STOCK STRUCTURE

PHYSIOLOGY, GROWTH, AND LONGEVITY

ABUNDANCE AND SIZE STRUCTURE

YIELD, POPULATION DYNAMICS, AND MANAGEMENT

5 The Behavior of Dolphins and Tuna in the ETP

GENERAL DOLPHIN BIOLOGY AND ECOLOGY

THE TUNA-DOLPHIN RELATIONSHIP

FEEDING BEHAVIOR

BEHAVIOR OF DOLPHINS AND TUNA IN THE TUNA-SEINING OPERATION

Sighting Dolphin Herds

The Chase.

The Set

Net Closed and Pursed

6 Dolphin Mortality and Abundance

ESTIMATING INCIDENTAL DOLPHIN MORTALITY

Methodological Considerations

Sampling Design

Ratio Estimates

The Observer Effect

MORTALITY ESTIMATES FOR 1959-1990

1959-1972

1973-1978

1979-1990

FACTORS AFFECTING TOTAL MORTALITY ESTIMATES

Fishing Effort on Dolphins

Factors Directly Affecting Dolphin Mortality

Catch of Tuna in Set

Vessel Captain

Species or Stock Caught

Area of Capture and Habituation

Flag of Vessel

Time of Capture (Day rs. Night Sets)

Duration of Set

Presence of Strong Currents

Occurrence of Malfunctions

Alignment of the Fine-Mesh Panel

Use of Dolphin-Saving Procedures

Relationship Between Number of Vessels and Total Mortality

SIGNIFICANCE OF THE ESTIMATES OF MORTALLY AND ABUNDANCE

OVERVIEW: THE PAST, PRESENT, AND FUTURE

Historical Summary

Maintenance and Recovery of Dolphin Populations

7 Techniques for Reducing Dolphin Mortality

SMALL MODIFICATIONS OF CURRENT METHODS

Medina Double Corkline

Jet Boat

Current Profiler

Pear-Shaped Snap Rings

Small-Mesh Medina Panel

Third Fine-Mesh Strip

Safety Crook

MAJOR MODIFICATIONS OF CURRENT METHODS

Modifications to Reduce Frequency of Canopies

Modifications to Reduce Frequency of Roll-Ups

Modifications by Insertion of Barriers Between Tuna and Dolphins

Species Selectivity

Modifications to Improve Escape of Dolphins from the Backdown Channel

No Backdown

Other Purse-Seine Variations

POTENTIAL BEHAVIOR-BASED RELEASE OF DOLPHINS

Pre-Backdown Release of Dolphins

Backdown Release of Dolphins

Dolphin Behavior on Release

BREAKING THE TUNA-DOLPHIN BOND

ALTERNATIVE METHODS OF LOCATING YELLOWFIN TUNA

Acoustical Methods

Other Methods.

ALTERNATIVES TO DOLPHIN-ASSOCIATED FISHING

Fish-Aggregating Devices

History and Perspective

Status

Potential

Conclusions

Non-Purse-Seine Techniques

Bait Boats

Midwater Trawls

Pair Trawls

Incidental Catch of Dolphins in Trawls

A Hypothetical Trawling Technique for Tuna in the ETP

Gillnets

REGULATORY ALTERNATIVES

Immediate Prohibition of All Dolphin Mortality from Fishing

Dolphin Mortality Certificates

Incentives for Tuna Fishing with Alternative Gear

Price Incentives for Fishing on Non-Dolphin-Associated Tuna

Captain Performance Standards

Training and Evaluation of Fishing Captains

Initial Training

Measuring the Captains' Performance

Remedial Actions

8 Recommendations

RECOMMENDATIONS CONCERNING THE ETP TUNA-DOLPHIN FISHERY

Vessel-Captain Education, Certification, Incentives, and Monitoring

Modifications of Purse-Seine Gear and Methods

Tuna and Dolphin Behavior in and Around the Seine

The Effects of Chasing Dolphin Herds

Sunset Set Tests

Bubble Tests

The Potential for Maneuvering Tuna and Dolphins Inside the Seine and Dolphin Release-Gate Tests

Research on Behavior of Tuna and Dolphins

Oceanographic Correlates

Simultaneous Tracking of Dolphins and Associated Yellowfin

Tracking Flotsam-Associated Yellowfin Tuna

Studies Using Fish-Aggregating Devices

Satellite Monitoring of Radio-Tagged Dolphins

RECOMMENDATIONS FOR HARVESTING TUNA NOT IN ASSOCIATION WITH DOLPHINS

Night Behavior of Tuna and Dolphins

New Methods of Purse Seining Large Yellowfin Without Encircling Dolphins

SUMMARY

References

Appendix 1

Appendix 2

Appendix 3

NOTICE TO FISHERMEN TAGGED DRIFTING OBJECTS

Index.

Notes:

Bibliographic Level Mode of Issuance: Monograph

Includes bibliographical references (p. 120-128) and index.

ISBN:

1-280-20310-2

9786610203109

0-309-55610-4

0-585-08535-8

OCLC:

43475708