Predicting overfishing and extinction threats in multispecies fisheries

Significance Threats to species from commercial fishing are rarely identified until species have suffered large population declines, by which time recovery can require costly remedial actions, such as fishery closures. We present a mechanistic approach to predicting the threats of future extinction or severe depletion posed by current multispecies fishing practices to a given population. We show that severe depletions recently experienced by four Pacific tuna and billfish populations could have been predicted in the 1950s, using our approach. Our results demonstrate that threatened species can be identified long before they experience severe population declines, providing time for preventative adjustments in fishing practices before consequences become severe and fishery closures or other socioeconomically disruptive interventions are required to protect species. Threats to species from commercial fishing are rarely identified until species have suffered large population declines, by which time remedial actions can have severe economic consequences, such as closure of fisheries. Many of the species most threatened by fishing are caught in multispecies fisheries, which can remain profitable even as populations of some species collapse. Here we show for multispecies fisheries that the biological and socioeconomic conditions that would eventually cause species to be severely depleted or even driven extinct can be identified decades before those species experience high harvest rates or marked population declines. Because fishing effort imposes a common source of mortality on all species in a fishery, the long-term impact of a fishery on a species is predicted by measuring its loss rate relative to that of species that influence the fishery’s maximal effort. We tested our approach on eight Pacific tuna and billfish populations, four of which have been identified recently as in decline and threatened with overfishing. The severe depletion of all four populations could have been predicted in the 1950s, using our approach. Our results demonstrate that species threatened by human harvesting can be identified much earlier, providing time for adjustments in harvesting practices before consequences become severe and fishery closures or other socioeconomically disruptive interventions are required to protect species.

[1]  J. Hampton,et al.  Stock assessment of albacore tuna in the south Pacific Ocean , 2003 .

[2]  Milner B. Schaefer.  Some aspects of the dynamics of populations important to the management of the commercial marine fisheries , 1991 .

[3]  J. Holmes.  International Scientific Committee for Tuna and Tuna-Like Species in the North Pacific Ocean , 2009 .

[4]  E. Angulo,et al.  Rarity Value and Species Extinction: The Anthropogenic Allee Effect , 2006, PLoS biology.

[5]  R. Hilborn,et al.  Status and Solutions for the World’s Unassessed Fisheries , 2012, Science.

[6]  J. Brodziak,et al.  Model averaging and probable status of North Pacific striped marlin, Tetrapturus audax. , 2010 .

[7]  D. L. Alverson,et al.  By-Catch: Problems and Solutions , 2000 .

[8]  F. Badalamenti,et al.  The economic sustainability of artisanal fisheries: the case of the trawl ban in the Gulf of Castellammare, NW Sicily , 2003 .

[9]  R. E. Johannes,et al.  The case for data-less marine resource management: examples from tropical nearshore finfisheries. , 1998, Trends in ecology & evolution.

[10]  Carl J. Walters,et al.  Ecopath with Ecosim: methods, capabilities and limitations , 2004 .

[11]  Boris Worm,et al.  Global catches, exploitation rates, and rebuilding options for sharks , 2013 .

[12]  Ray Hilborn,et al.  Apparent Stock Recruitment Relationships in Mixed Stock Fisheries , 1985 .

[13]  T. Aqorau.  Western and Central Pacific Fisheries Commission , 2009, The International Journal of Marine and Coastal Law.

[14]  Tinker,et al.  Killer whale predation on sea otters linking oceanic and nearshore ecosystems , 1998, Science.

[15]  N. Dulvy,et al.  Methods of assessing extinction risk in marine fishes. , 2004 .

[16]  R. Hilborn,et al.  Rebuilding Global Fisheries , 2009, Science.

[17]  Kazuhiko Hiramatsu,et al.  Stock assessment of bigeye tuna in the western and central Pacific Ocean , 2004 .

[18]  S. Robinson,et al.  Food Security: The Challenge of Feeding 9 Billion People , 2010, Science.

[19]  J. Ragle,et al.  IUCN Red List of Threatened Species , 2010 .

[20]  Predicting species vulnerability with minimal data to support rapid risk assessment of fishing impacts on biodiversity , 2012 .

[21]  E J Milner-Gulland,et al.  Quantification of Extinction Risk: IUCN's System for Classifying Threatened Species , 2008, Conservation biology : the journal of the Society for Conservation Biology.

[22]  Nick Davies,et al.  Stock assessment of yellowfin tuna in the western and central Pacific Ocean , 2005 .

[23]  Cóilín Minto,et al.  Examining the knowledge base and status of commercially exploited marine species with the RAM Legacy Stock Assessment Database , 2012 .

[24]  Nick Davies,et al.  St Meeting of the Scientific Committee of the Western and Central Pacific Fisheries Commission Wcpfc–sc1 Stock Assessment of Skipjack Tuna in the Western and Central Pacific Ocean , 2022 .

[25]  D. Tittensor,et al.  Range contraction in large pelagic predators , 2011, Proceedings of the National Academy of Sciences.

[26]  Hawkins,et al.  Extinction risk in the sea. , 1999, Trends in ecology & evolution.

[27]  R. Hilborn,et al.  Escaping the tyranny of the grid: a more realistic way of defining fishing opportunities , 2005 .

[28]  C W Clark,et al.  Current Problems in the Management of Marine Fisheries , 2007, Science.

[29]  Colin W. Clark,et al.  Mathematical Bioeconomics: The Optimal Management of Renewable Resources. , 1993 .

[30]  H. B. Wilson,et al.  When should we save the most endangered species? , 2011, Ecology letters.

[31]  J. StewartIan,et al.  Modeling co-occurring species: a simulation study on the effects of spatial scale for setting management targets , 2013 .

[32]  R. Watson,et al.  High Value and Long Life—Double Jeopardy for Tunas and Billfishes , 2011, Science.

[33]  Ransom A. Myers,et al.  Maximum reproductive rate of fish at low population sizes , 1999 .

[34]  S. Harley,et al.  Population Trends in Pacific Oceanic Sharks and the Utility of Regulations on Shark Finning , 2013, Conservation biology : the journal of the Society for Conservation Biology.

[35]  J. Reynolds,et al.  Marine Fish Population Collapses: Consequences for Recovery and Extinction Risk , 2004 .

[36]  N. Dulvy,et al.  Global population trajectories of tunas and their relatives , 2011, Proceedings of the National Academy of Sciences.

[37]  J. Boyce.  An Economic Analysis of the Fisheries Bycatch Problem , 1996 .

[38]  Rebecca L. Lewison,et al.  Quantifying the effects of fisheries on threatened species: the impact of pelagic longlines on loggerhead and leatherback sea turtles , 2004 .

[39]  M. Hinton,et al.  Stock assessment of blue marlin (Makaira nigricans) in the Pacific using MULTIFAN-CL , 2003 .

[40]  William W. L. Cheung,et al.  A Fuzzy Logic Expert System to Estimate Intrinsic Extinction Vulnerabilities of Marine Fishes to Fishing , 2004 .

[41]  Ransom A. Myers,et al.  What can be learned from the collapse of a renewable resource? Atlantic cod, Gadus morhua, of Newfoundland and Labrador , 1994 .

[42]  Stock Assessment of North Pacific Swordfish (Xiphias gladius) in 2009 , 2010 .

[43]  C. Clark.  Profit Maximization and the Extinction of Animal Species , 1973, Journal of Political Economy.

[44]  Rebecca L. Lewison,et al.  Understanding impacts of fisheries bycatch on marine megafauna , 2004 .

[45]  Erika A. Zollett,et al.  Reducing sea turtle by-catch in pelagic longline fisheries , 2006 .

[46]  Patrick Lehodey,et al.  Shifting from marine reserves to maritime zoning for conservation of Pacific bigeye tuna (Thunnus obesus) , 2012, Proceedings of the National Academy of Sciences.