(October 28, 2002) Beneath the oceans´ surface are some of Earth´s most diverse and productive ecosystemscolorful coral reefs, dense kelp forests, and vibrant estuaries. Increasingly, these habitats are straining from the weight of pollution, coastal development, and harmful fishing practices, endangering the ecological and economic benefits they produce.
In a new report, Ecological Effects of Fishing in Marine Ecosystems of the United States, prepared for the independent Pew Oceans Commissionthe latest in a series of science reports on the threats facing the nation´s oceansscientists find that many current fishing activities are harming the very ecosystems on which future fishing depends, and that this phenomena is worsening. Leon Panetta, chair of the Pew Oceans Commission, released the report today in Santa Barbara, California, in conjunction with the California and the World Ocean Conference.
This report is one of many that has been presented to the Commission for our consideration as we arrive at or final recommendations. said Panetta. For centuries, we have viewed the oceans as an infinite resource beyond our capacity to harm. We now know that this is not true. Our oceans are more vulnerable and more valuable than we ever imagined. If we want to sustain America´s proud fishing industry, then we need to take a hard look at how pollution, development, and fishing activities are harming the oceans.
In their report to the Commission, authors Paul Dayton of Scripps Institution of Oceanography, Simon Thrush of the National Institute of Water and Atmosphere Research (New Zealand), and Felicia Coleman of Florida State University, find overwhelming evidence that the unintended consequences of fishing on marine ecosystems are severe, dramatic, and in some cases, irreversible.
The authors find that certain fishing activities can:
Deplete populations, which alter food webs and ecosystems; Remove top predators, thereby disrupting predator-prey relationships; Endanger marine mammals, seabirds, sea turtles, and certain species of fish; and Alter the structure, function, productivity, and resilience of marine habitats.
If we are serious about saving our fisheries and protecting the sea´s biodiversity, then we need to make swift, and perhaps painful, decisions to preserve and maintain the oceans´ ecosystems, said Dr. Dayton, lead author on the report. The time has come to reorient fishery management around the goal of protecting ecosystems and to instill flexible management that emphasizes caution.
The report´s authors address three primary threats to the long-term health of ocean ecosystems: overfishing, bycatch (the incidental take of nontarget species), and habitat damage.
Overfishing. Worldwide, some 25 to 30 percent of all commercial fisheries are experiencing some degree of overfishing, with an additional 40 percent heavily or fully exploited. In the United States, the federal government knows the status of only one-third of the stock it manages, of which a third are overfished or experiencing overfishing. The report finds that a significant ramification of overfishing is the decreased prey available to predators, often times resulting in a ripple effect throughout an ecosystem. This phenomenon is compounded by what is often called serial overfishing, where fisherman move from one species to the next as populations decline. A final concern is what is termed fishing down the food web, where fishing shifts from higher trophic levels to lower trophic levels, resulting in a top-down ecological disruption.
Bycatch. Scientists estimate that up to 25 percent of the world´s fisheries catch is bycatchinvertebrates, fish, seabirds, turtles, and marine mammals accidentally captured along with target species and discarded dead or dying. Bycatch has severely depleted most species of turtles, many marine mammals, several species of albatross, and several skates and rays. The report finds that bycatch extends the ramifications of fishing to a much wider sector of ocean life, with repercussions to the functioning and diversity of ecosystems.
Habitat Disturbance. Protecting essential habitat from human activities is a vital component of successful fishery management. Fishing activities can have temporary and long-term effects on habitat that is critical to the various life stages of exploited species. The seas´ rocks, ledges, seagrass beds, sponge gardens, and shellfish beds contribute to the growth and survival of juvenile fish and serve as the focal point for foraging and spawning adults.
The authors propose a new approach to fishery management based upon (1) a major commitment to understanding and monitoring ocean ecosystems and (2) a proactive and adaptive approach founded upon ecosystem-based planning and marine zoning. This begins by reorienting fishery and ocean management programs toward the primary goal of protecting natural resources. It also requires an increased investment in ecosystem research and monitoring to better address the trade-offs that result from management decisions. Finally, a new approach to fishery management must move from the current single-species model to one that considers the entire ecosystem.
Poor information on bycatch, discarding, and basic life history are the bane of fisheries scientists, said Dr. Coleman. Couple this with ineffective regulations, nonexistent brakes on developing capacity, and inadequate support of law enforcement, and disaster ensues. If we are to ensure sustainable fisheriesboth commercial and recreationalwe must shift fishery management´s emphasis from a single-species approach focused on short-term benefits to an integrated approach that acknowledges the tradeoffs we are willing to accept in our choice of management options.
The independent Pew Oceans Commission is conducting the first review of polices and laws needed to sustain and restore living marine resources in over 30 years. The Commission includes leaders from the worlds of science, fishing, conservation, business, and politics. For the past two years, Commission members have traveled to coastal communities to talk to people about the problems facing our oceans and to explore new ways to address them. Ecological Effects of Fishing is the latest in a series of reports prepared for the Commission to inform their deliberations. Previous reports covered marine pollution, coastal sprawl, introduced species, and aquaculture. The Commission will release additional reports and white papers on fishery management, marine reserves, and the economics of fishing in the coming weeks.
The Pew Oceans Commission will present its final recommendations for a new national ocean policy to Congress and the nation in early 2003. Information about the Commission, including copies of its science reports, is available online at www.pewoceans.org.
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