An NCMC Issue Paper

ECOSYSTEM PRINCIPLES, OVERFISHING AND BYCATCH IN MARINE FISHERIES by Ken Hinman National Coalition for Marine Conservation

Fish don’t form ecological societies or hold and multi-mile drift lines, because we can; taking conferences like this one.1 We do. What too much and throwing almost as much back, distinguishes us most from all the other animals is unwanted. Meanwhile, in order to support that they know instinctively how to relate to their ourselves at home on land, we degrade coastal environment, whereas we, alone, have the areas, home to the fish we need more than they existential problem of having to figure it out for need us. ourselves. In doing so, we make a lot of mistakes. That’s why so much of fisheries management as Don’t get me wrong. I don’t ascribe to the we know it is repairing the damage, or even just brand of environmentalism that dissociates humans trying to understand it. from nature, as if nature is good and we’re bad. Nature is neither good nor bad, and we are both. A We think we’ve got a fair idea of what goes on true environmentalist recognizes and accepts that beneath the waves. It’s a fish-eat-fish world. But humans are an integral part of nature – no more, no the chain of life in the ocean is, to borrow Joseph less than any other species, and like every product Wood Krutch’s phrase, “the simplicity that isn’t of evolution, selfishly and instinctively partial to simple.” (Krutch 1956) our own.

Big fish eat little fish and, in their turn, are The idea of expanding our current practice of preyed upon by even bigger fish. Some prey fisheries management to include ecosystem species turn the tables by eating the young of their principles is an idea whose time has come. If predators. Fish compete with each other, as well nothing else, it serves to remind us that we are as with mammals and seabirds, in a life or death predators in a natural system where no animal struggle for a finite amount of food in a limited exists apart from its environment and what we do amount of space. The numbers of marine animals, to one species, to some degree, we do to them all. from the deep ocean to the tideflats, are bounded by the quality and quantity of their physical In over 20 years working in the field of marine habitat. fish conservation, I’ve spent a large part of that time working with fishermen and fishery managers Atop it all – literally - in modern, well-armed to repair the damage we’ve done to other apex fishing vessels, floats the supreme predator, fishing predators – namely the large pelagics - the tunas, up and down the food chain, according to our billfishes and sharks. wants as much as our needs. Sharks scare people because, looking into their impenetrable black The problems I’m going to discuss, in the eyes, we see a predator without conscience. But ecosystem context, are: what makes us the most dangerous predator of all • Overexploitation; is that we are limited only by the limits we set for • ourselves. We prey with huge wrap-around nets Our lack of attention to predator-prey interactions; and,

• Bykill, caused by the use of indiscriminate 1 This paper was presented during a panel on fishing gear. Fisheries Ecology at a conference sponsored by the American Society of Limnology and In each case, I’m going to suggest ways to Oceanography and the Ecological Society of change the way we manage the pelagic fisheries in America, St. Louis, Missouri, June 11, 1998.

1 An NCMC Issue Paper order to preserve the integrity, diversity and resultant increase in prey species could productivity of marine ecosystems. dramatically alter the makeup of their ecological tier, with some species thriving at the expense of Prevent Ecosystem Overfishing others, or trigger an environmental backlash of The ocean’s giant fishes are among the most parasites, disease and depletion of forage species. threatened animals in the sea. Virtually all species These changes could in turn interfere with our of large pelagic fish in the Atlantic Ocean are efforts to rebuild predator populations. overfished or approaching that condition. In September of last year, the National Marine Pauley et al recently noted a global trend Fisheries Service released a Report to Congress on toward fishing down marine food webs, to lower the Status of U.S. Fisheries. Of the 86 species and lower trophic levels as populations at higher designated as “overfished,” 26 are Atlantic large tropic levels are overexploited. He postulates that pelagics: bluefin tuna, swordfish, blue marlin, this trend, if it is allowed to continue, could lead to white marlin, and 22 species of large coastal widespread fisheries collapses. (Pauley 1998) sharks. Bigeye tuna, following a November 1997 stock assessment, will be added to the list later this The objective of fishery management should be year. to regulate exploitation so as to maintain a balance within fish communities as close to natural as The billfishes, sharks and tunas are keystone possible. That balance needs to be both among predators in the sea. They help maintain a healthy species and within them; that is, preserving an age balance in marine ecosystems by contributing to structure and sex ratio that will be stable and stability, structure and predictability. By removing resilient to environmental as well as man-caused so many of these predators, we are weakening an fluctuations. This is the antithesis of managing entire tier at the top of the food chain, with commercial fisheries for their maximum unpredictable but certainly unhappy ecological sustainable yield, which sets maximum harvesting consequences, far beyond the social, economic and levels for each species, without regard to that moral costs of depleted fisheries. species’ place in the food chain, or the condition of other, related species. Never before have such a broad range of large ocean pelagics been exploited so heavily, or have My first set of recommendations is that fishery their numbers been so low. What effect could managers: widespread depletion of these big predators have ♦ on the ocean ecosystem, on other species of fish? Put priority on rebuilding overfished We’ve entered uncharted waters. populations of large pelagics to levels higher than required to produce the maximum Overexploitation of large predators could sustainable yield; conceivably have a greater, more enduring impact ♦ Restore a stable age structure and sex ratio on the stability of an ecosystem than removing within the population; species farther down the chain, according to the ♦ Adopt and implement the precautionary late Canadian fisheries biologist Peter Larkin. approach in all things, including the Predators are generally longer-lived than their introduction of new fisheries and expansion of prey, and are thus slower to respond to changes in existing fisheries; and, their environment, or to fill niches left by the ♦ Set catch levels for target species disappearance of other predators. (Larkin 1979) conservatively with a built-in buffer against scientific uncertainty. In addition, says Larkin, because fisheries for Integrate Management of Associated Species predators usually harvest a range of predators - and that’s certainly true in the opportunistic and non- In our jobs as stewards of the ocean’s fishery selective longline fisheries for tunas and swordfish resources, we attempt to conserve each species - increased exploitation means the total amount of alone, just as we fish for them. We perform stock predation in the ecosystem is reduced. The assessments on a species-by-species basis and set

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catch limits within the same little boxes. This fishery management plans for squid, mackerel and narrow approach doesn’t account for inter-actions herring, along with plans for many of the large among predators and prey; the effect of fishing one pelagic species that feed on them, none of these on the other; or fishing operations that kill a wide plans set allowable catches or desirable population range of species indiscriminately. levels with an understanding or consideration of how they impact the others. The main reason For years, many of us in fish conservation ecosystem relationships are not being adequately lamented that all the attention went to the so-called considered is a lack of direction as to what “charismatic megafauna,” the great whales and information is required and how it should be used dolphins. That’s changing. More recently, the in the real world of managing fisheries. ocean’s giant fishes have pushed their way into the public mind. But the little fishes are just as Obviously, we could use a better understanding important -– to the marine ecosystem in general as of how ecosystems function than we currently well as to the survival of large predators – and they have. Research in this area will require new need our attention, too. money and more time. Notwithstanding, there are a number of things we can set about doing right Because they are overfished, fishing for away. swordfish, bluefin tuna, marlins and large coastal sharks is under strict regulation and likely to get More than anything else, we’re talking about stricter. It wouldn’t make sense, then, to changing a way of thinking, or an approach to compound the problem by also overfishing the making decisions that is different from, but species these fish depend on for food. But we are nevertheless grows out of, our current approach. at risk of doing just that. When we talk about managing the impact of fishing activities in such a way as to preserve Billfish and tuna feed on “forage” species such ecosystem integrity, what it boils down to is as squid, mackerel and herring. In the Atlantic, coordinating the objectives of fishery management there is rapidly increasing exploitation of these so- plans for related species. called “underutilized species,” a term that is anathema to ecologists and environmentalists alike My second set of recommendations is that and is anyway an uncomfortable characterization fishery managers: because it confirms that fully- and over-utilized are ♦ Amend all fishery management plans to the rule rather than the exception. identify important species interactions;

♦ There are already signs that the increasing Establish a threshold (either population level harvest of squid and other forage species is having or fishing mortality rate) which takes into an adverse effect on the animals that feed on them. account those interactions. Given that there Sport and commercial fishermen from Maine to will be uncertainty about cause and effect, Virginia report seeing fewer and smaller schools of managers should apply the precautionary baitfish where once they were abundant. The approach to setting allowable catch levels; and, stomach contents of fish caught by anglers and ♦ If management objectives are found to be in stranded seals and porpoise indicate changes in conflict, the authors (responsible agencies) of diet to non-traditional species and, in some cases, the plans in question should work out an starvation, both signs that these animals are having ecologically based process for harmonizing trouble finding food. those objectives. Control All Sources of Fishing Mortality Managers not only need to maintain forage species at sustainable levels, but also at levels that Finally, there is the issue of bycatch. The will sustain the recovery of predator species to predominant gear in the pelagic fisheries in the their historic abundance. Unfortunately, there is Atlantic is the longline. Longlines consist of no way to address these and other concerns in the extraordinarily long floated mainlines – often current management process. Although there are stretching over 30 miles - from which thousands of

3 An NCMC Issue Paper baited hooks are suspended in the deep ocean, By the very nature of fishing with non-selective “searching” for fish. They are commonly used to drift longlines, catches are indiscriminate and catch large, highly valuable swordfish and tunas, therefore uncontrollable. Catch limits designed to but longlines also capture an enormous quantity of conserve target and non-target species alike are non-target fish, including marlins and sharks as rendered ineffective. With little control over what well as juveniles of the target species, that are the is captured and killed, fishery managers can only accidental casualties of the indiscriminate hooks. regulate what fishermen keep and land. As a result, massive amounts of unwanted and illegal Bycatch and the subsequent dead discard of fish and other animals are thrown dead back into unwanted or prohibited fish is an unremitting the sea – on average, one quarter of the total catch consequence of fishing with longlines. The - contributing to overfishing and impeding the Atlantic’s severely overfished populations of recovery of depleted fish populations. Between swordfish, sharks and marlins cannot, in my view, 30-40% of the catch of swordfish are juveniles be restored to sustainable levels, unless under the legal size; 40,000 fish were thrown back governments strictly curtail longline bykill. dead in 1996. Nine of ten sharks caught on longlines are discarded, with nearly a third dying In the early 1990s, amid the well-publicized as a result of capture. Although commercial debate over the use of high seas drift nets, the so- longlining for marlins is illegal in the U.S., six called "walls of death" that entangled huge times as many billfish are killed as bycatch than numbers of non-target fish, marine mammals and are landed by all other fishermen combined. seabirds while fishing for tuna and squid, a spokesman for Japanese fishing interests defended Two years ago, in an effort to improve drift nets and other indiscriminate fishing gear as conservation of large pelagic fish in the Atlantic, I less environmentally destructive than more undertook a study of the available options for selective methods of fishing. "Many fishery minimizing bykill in the longline fisheries. The scientists," he argued, "believe that fishing that results of that study are published in the National removes a full cross-section of marine life in a Coalition for Marine Conservation report, Ocean fishing area is ecologically better than a method Roulette. (Hinman 1998) that removes a few selected species." To briefly summarize the results of this lengthy Like the ocean itself, this argument may appear report, I’ve concluded that longline gear cannot be all right on the surface, but looking deeper, we find modified to fish selectively, and therefore the only something as fundamentally wrong with this line way to minimize bykill and curb fishing mortality of thinking as with the fishing practices it excuses. is to substantially reduce the amount of gear in the water and to remove it completely from areas The success of fisheries management quite where it does the most damage. simply depends on our ability to regulate the number of animals we kill. Whether our aim is My third set of recommendations is that fishery protecting a single species from over-exploitation managers: or preserving the ocean’s biodiversity - and it ♦ Establish no-longlining zones, also commonly should be both - the goal is the same: we must referred to as time and area closures, where the control fishing mortality. Even those who believe bycatch of protected or overfished species or it is more ecologically responsible to harvest less age classes (spawning and/or juvenile fish) is selectively and utilize a greater variety of species highest or most detrimental to the recovery of advise that removals must be conservative, “at the resource; rates that are sufficiently below (maximum ♦ Ssupplement area closures with gear sustainable yield) as to provide a margin of safety” restrictions in open areas to enhance the for individual species. (Larkin 1979) survival of incidentally-caught fish, including but not limited to number of hooks per set, maximum length of mainline and period of

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soak time (time between setting the gear and Krutch, Joseph Wood. 1956. The Great Chain of retrieving it); and, Life. Pyramid Books, New York. ♦ Count dead discards against all landing Larkin, P.A. 1979. Predator-Prey Relations in allowances as an incentive for fishermen to Fishes: An Overview of the Theory. Predator- adopt more selective fishing practices or gear. Prey Systems in Fisheries Management. Sport Fishing Institute, Washington, DC. Hinman, K. 1998. Ocean Roulette: Conserving NMFS 1997. Report to Congress: Status of Swordfish, Sharks and other Threatened Pelagic Fisheries of the United States. National Marine Fishes in Longline-Infested Waters. National Fisheries Service. September 1997. Coalition for Marine Conservation, Leesburg, Pauley, D., V. Christensen, J. Dalsgaard, R. VA. Froese, F. Torres, Jr. 1998. Fishing Down Marine Food Webs. Science Vol. 279.

The National Coalition for Marine Conservation, founded in 1973, is the nation’s oldest public advocacy organization exclusively dedicated to conserving ocean fish and their environment. For more information on this or other issues related to marine fish conservation, write to NCMC, 3 North King Street, Leesburg, Virginia 20176 or call (703) 777-0037.

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