CHAPTER7

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TUNA TALES TUNA I A Fishery Management Case Study: Yellowfin Tuna and Dolphins in the Eastern Tropical Pacific TUNA II The World’s Tuna Fisheries

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Yellowfin tuna

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Commercial catches of yellowfin tuna

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Background information on the tuna/dolphin problem Problem is confined to the eastern tropical Pacific, where yellowfin tuna tend to congregate under schools of certain species of dolphins For many years fishing was done by chumming (pole and line) with no impact on dolphins Purse seining phased in during last few years of 1950s Combination of purse seine fishing of tuna located under schools of dolphins proved deadly to dolphins and damaging to tuna stocks Tuna can be found by several methods. “Porpoise Sets” actually account for less than half the purse seine sets during the 1970s. Log sets a common alternative Key strategies for releasing dolphins from net include backing down procedure (1960) and Medina panels (1971)

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A log used by tuna fishermen to attract schools of tuna

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A floating board that has attracted some small fish

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A piece of rope that has also attracted some fish

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Another floating board that has attracted some fish

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TUNA - DOLPHIN ASSOCIATION TUNA These animals have a sense of smell that works in the water They are not known to be echo-locators DOLPHINS Their olfactory sense is not designed to work in the water They have excellent sonar abilities Might their combined sensory capabilities be mutually beneficial?

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Searching for tuna using high power binoculars

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Helicopter used to search for schools of tuna

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Tuna boat in process of setting purse seine

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Final stages of setting the purse seine

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Tuna boat with purse seine encircling school of dolphins

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Tuna caught in purse seine

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Beginning job of removing tuna from purse seine with brail net

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Dipping tuna from net using brail net

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Lifting brail net out of the water

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Initial stages of backing down operation

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Dolphins escaping from purse seine during backing down operation

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Dolphins escaped from tuna net

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Schematic Depiction of a “Porpoise Set”

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Marine Mammal Protection Act – 1972 “Certain species and population stocks of marine mammals are, or may be, in danger of extinction or depletion as a result of man’s activities . . . . They should not be permitted to diminish below their optimum sustainable population . . . . Measures should be immediately taken to replenish any species or population stock which has already diminished below [its optimum sustainable] population.” “In any event it shall be the immediate goal that the incidental kill or incidental serious injury of marine mammals permitted in the course of commercial fishing operations be reduced to insignificant levels approaching a zero mortality and serious injury rate.” NMFS permits voided by Judge Richey on grounds that NMFS had inadequate information on which to base kill quotas First and second status of porpoise workshops – 1976 and 1979 Optimum sustainable population defined to be any stock size between 65% and 80% of the virgin stock

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NMFS Implementation of MMPA with respect to dolphin stocks Determination of numbers of dolphins in various stocks (1976-1979) Use of virtual population analysis to estimate size of virgin stocks (assumed to be size of stocks in 1959) Two stocks appear to be well below the OSP – eastern spinner and northern offshore spotted Sets on eastern spinners prohibited. 90% of subsequent sets are on spotted dolphins Judge Richey approves NMFS permits. Quotas steadily decline with time

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rate of change =

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rate of change = Theoretically, maximum rate of change is when N = 50% of K r5 (1-5/10) = r5 (1-0.5) = r5 (0.5) = r(2.5) r9 (1-9/10) = r9 (1-0.9) = r9 (0.1) = r(0.9) r1 (1-1/10) = r1 (1-0.1) = r1 (0.9) = r(0.9) When N = 50% of K: When N = 90% of K: When N = 10% of K:

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Maximum Net Productivity Curves Mathematical Ideal Reality for Large Mammals . . .

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Subsequent developments Early 1980s – U.S. wants to put observers on all tuna boats. Observers on fewer than 50% of U.S. boats and only a handful of foreign boat-trips. Early 1980s – U.S. wants to ban sundown sets Tuna boats start to drop out of U.S. fleet – 155 in 1976, 34 in 1987, 29 in 1990. Late 1980s – dolphin kills start to increase

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1988 Amendments to the MMPA Must be 100% observer coverage of U.S.-registered boats With some exceptions, U.S. boats cannot use sundown sets Nations intending to export tuna to the United States must do the following: have a regulatory program comparable to that of the U.S. (no sundown sets) dolphin mortality must be no more than 1.25 the U.S. rate no more than 15% of kill can be eastern spinners participate in IATTC observer program submit annual report concerning performance

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To avoid laundering of tuna Any nation exporting yellowfin tuna to the U.S. must identify the harvesting nation Such exporters must ban the entry of yellowfin tuna from any nation that the U.S. embargoes Sanctions will be imposed if harvesting and exporting nations fail to comply with these requirements within six months.

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Dolphin-safe tuna 1990 – Dolphin Protection Consumer Information Act establishes standards for “dolphin-safe” April 12, 1990 – Star-Kist, Bumble Bee, and Chicken of the Sea announce that they will not buy tuna caught using porpoise sets 1991 – U.S. embargoes challenged by Mexico – General Agreement on Tariffs and Trade (GATT) Reported dolphin mortalities continue to drop. Kill has been less than 2,000 animals per year since 1998

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1997 – International Dolphin Conservation Program Act – amends certain provisions of the MMPA. Secretary of Commerce to make final finding concerning the dolphin-safe label and the impact of the fishery on dolphin stocks by 12/31/02. 12/31/02 – NMFS rules that use of porpoise sets is having “no significant adverse impact on dolphin populations in the Eastern Tropical Pacific Ocean.” This finding effectively changes the definition of dolphin-safe to include tuna caught with porpoise sets as long as no dolphins were killed or seriously injured.

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Lessons Learned? Pluses U.S. consumers, via their government, pushed effectively for the implementation of an appropriate management plan There were benefits to the fishery to accept the management plan 1. Main markets didn’t want to buy dead dolphin 2. Spared dolphins live to help find tuna again Minuses Expenses to the industry have forced much of the fishing fleet to jurisdictions where the management plan can be evaded Some of the resulting regulations against “tuna laundering” deserve lots of air time on late night talk shows

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Modern tuna boat at dedication ceremonies in San Diego

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Lowering speed boat into the water to help with herding dolphins

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Speed boat about to be released from tuna boat

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Power boat steering wheel after a bumpy ride

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Releasing pelican hook to allow purse seine to pay out behind tuna boat

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Very early stages of setting seine net. Smaller boat serves as a sea anchor

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Dye used to discourage escape of dolphins while net is being deployed

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Purse seine with cork line and brail net

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Purse seine net folded on deck with pursing rings

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Power block used to haul in the purse seine

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Small boat providing sea anchor support for tuna boat during initial stages of hauling in purse seine

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Disengaging tangled rings during pursing operation