Translator Disclaimer
1 April 2004 Seabird Bycatch: Trends, Roadblocks, and Solutions
Author Affiliations +

The following critiques express the opinions of the individual evaluators regarding the strengths, weaknesses, and value of the books they review. As such, the appraisals are subjective assessments and do not necessarily reflect the opinions of the editors or any official policy of the The American Ornithologists' Union.

Seabird Bycatch: Trends, Roadblocks, and Solutions.–Edwin F. Melvin and Julia Parrish, Eds. 2001. University of Alaska Sea Grant AK-SG-01-01, Fairbanks, Alaska. vii + 206 pp., ISBN 1-56612-066-7. Cloth, $20.00.—Mortality of seabirds resulting from bycatch in various types of fishing gear is an important global concern of ornithologists, fishers, oceanographers, conservationists, and managers. From presentations at a Pacific Seabird Group Symposium and an additional paper, the editors have drawn together important information about the issue in nine peer-reviewed articles, seven abstracts, and an opening symposium synthesis. The editors and many of the contributors have previously made comprehensive contributions to bycatch research and problem resolution.

In their synthesis, the editors emphasize the importance of educating fishers and fishery managers about effects of bycatch that are neither obvious nor intuitive. For instance, observations of seemingly few caught birds must be reconciled with the potential population consequences of those mortalities for seabird populations. The editors emphasize the importance of working partnerships with fishery interest groups and of incorporation fishers' knowledge in problem-solving exercises. Solutions need to be aimed at significantly reducing bycatch without significantly reducing target catch. In this regard, fishers prefer modification of equipment and operational procedures to spatial and temporal restrictions that are more likely to reduce profits. However, it is clear that strong seasonal and area effects are pervasive aspects of seabird × fishery interactions and need to be considered in comprehensive solutions. From a larger ecosystem perspective, attention must also be focused on the bycatch of marine turtles, mammals, sharks, and other fishes.

Many problems exist, and legislation is often weak, ineffective, and unenforceable. Cooper, Croxall, and Rivera point out that many albatrosses and petrels are killed in illegal fisheries for Patagonian toothfish (Dissostichus eleginoides; marketed as Chilean sea bass). Other problems occur in international waters beyond the bounds of national legislation. With the help of experts, the Food and Agricultural Organization of the United Nations (FAO) produced an International Plan of Action to reduce seabird bycatch in the world's oceans (IPOA-Seabirds). Recommended tactics include increasing the sinking rates of baited hooks on longlines with weights and thawed baits, dispensing hooks at night and from chutes below the water surface, installing bird-scaring lines and poles at vessel sterns, and minimizing fish and garbage discards that attract scavengers.

Long-term data collection by trained, independent and dedicated observers is essential, and may be effective in changing the behavior of skippers and crews. Scientists have certainly demonstrated successful methods for reducing bycatch. In this volume, Løkkeborg discusses the use of bird-scaring lines, which have reduced bycatch while also increasing catch-rates of the fishery's target species. Robertson, discussing experimental weighting of longlines, contends that sinking rates of >0.3 m s−1 used in conjunction with streamer lines could greatly reduce the bycatch of albatrosses in the fishery for Patagonian toothfish. Boggs demonstrates that camouflaging baits by dying them blue increased the effectiveness of streamer lines and weighted pelagic longlines for swordfish in Hawaii (the idea of camouflaging bait to reduce longline scavenging and bycatch was first suggested by fishers). Cousins, reporting on a workshop on the population dynamics of Black-footed Albatrosses (Diomedea nigripes), addresses the issue of assessing longlining bycatch and indicates that juveniles were killed more often than adults. Doubling observer coverage from 5% to 10% of fishing trips is a crucial, immediate need.

Edwards, Silva, Burg, Friesen, and Warheit provide an informative tutorial on molecular genetic markers and their potential uses in population analyses of seabird bycatch. Marker analyses can be used to identify otherwise unidentifiable bycatch specimens, to assess population origins of birds killed in fishing gear, and to evaluate the significance of bycatch on the genetic variation of source populations. Examples with Black-footed Albatrosses and Common Murres (Uria Aalga) are given.

Because circumstances change and ecosystem interactions are dynamic, strategies to reduce bycatch mortality must be flexible and adaptive. Forney, Benson, and Cameron report that area and depth closures of gillnet fisheries in central California during the 1980s successfully reduced avian bycatch, but that increased gillnet efforts in the late 1990s may have reversed the situation. They demonstrated a striking temporal and spatial correspondence between dead seabirds picked up on beach surveys and adjacent gillnet fishing effort for halibut. Using creative, novel approaches, Melvin, Parrish, and Conquest incorporated highly visible netting in the upper meshes of sockeye salmon (Oncorhynchus nerka) gillnets and pingers to reduce the bycatch of Common Murre and Rhinoceros Auklets (Cerorhinca monocerata) in Puget Sound. Fishers had pointed out that most birds and few salmon were caught in the upper portions of gillnets. Three complimentary approaches (gear modifications, abundance-based fishery openings, time-of-day restrictions) are considered to have the potential to reduce bycatch by ∼75% without affecting fishing efficiency. The Washington Fish and Wildlife Commission adopted regulations based on these findings, but the regulations did not apply to the U.S. treaty tribes or to the Canadian gillnet fleet (i.e. ∼90% of the fishery). Further, owing to those circumstances, the small nontreaty U.S. fleets sought injunctions against the regulations. As is clarified in Harrison's afterword on those gillnet fisheries, good science is inadequate for solving environmental problems (Ludwig et al. 1993). To prevent the unnecessary deaths of seabirds and other marine animals, it is clearly necessary to move beyond conservation biology into the sphere of conservation politics.

Literature Cited

1.

D. Ludwig, R. Hilborn, and C. Walters . 1993. Uncertainty, Resource Exploitation, and Conservation: Lessons from History. Science 260:1736. Google Scholar

Appendices

W. A. Montevecchi "Seabird Bycatch: Trends, Roadblocks, and Solutions," The Auk 121(2), 627-628, (1 April 2004). https://doi.org/10.1642/0004-8038(2004)121[0627:SBTRAS]2.0.CO;2
Published: 1 April 2004
JOURNAL ARTICLE
2 PAGES


SHARE
ARTICLE IMPACT
Back to Top