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Title: Global population trajectories of tunas and their relatives
Authors: Jose Juan-Jorda, Maria; Mosqueira, Iago; Cooper, Andrew B.; Dulvy, Nicholas K.; Freire, Juan
Citation: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2011, 108, 20650-20655
Abstract: Tunas and their relatives dominate the world's largest ecosystems and sustain some of the most valuable fisheries. The impacts of fishing on these species have been debated intensively over the past decade, giving rise to divergent views on the scale and extent of the impacts of fisheries on pelagic ecosystems. We use all available age-structured stock assessments to evaluate the adult biomass trajectories and exploitation status of 26 populations of tunas and their relatives (17 tunas, 5 mackerels, and 4 Spanish mackerels) from 1954 to 2006. Overall, populations have declined, on average, by 60\% over the past half century, but the decline in the total adult biomass is lower (52\%), driven by a few abundant populations. The trajectories of individual populations depend on the interaction between life histories, ecology, and fishing pressure. The steepest declines are exhibited by two distinct groups: the largest, longest lived, highest value temperate tunas and the smaller, short-lived mackerels, both with most of their populations being overexploited. The remaining populations, mostly tropical tunas, have been fished down to approximately maximum sustainable yield levels, preventing further expansion of catches in these fisheries. Fishing mortality has increased steadily to the point where around 12.5\% of the tunas and their relatives are caught each year globally. Overcapacity of these fisheries is jeopardizing their long-term sustainability. To guarantee higher catches, stabilize profits, and reduce collateral impacts on marine ecosystems requires the rebuilding of overexploited populations and stricter management measures to reduce overcapacity and regulate threatening trade.
Keywords: PACIFIC-OCEAN; MARINE FISHES; TROPHIC LEVEL; MANAGEMENT; ABUNDANCE; PATTERNS; EXPLOITATION; PREDATORS; DECLINES; TRENDS
Issue Date: 2011
Publisher: NATL ACAD SCIENCES
Type: Article
Language: English
DOI: 10.1073/pnas.1107743108
URI: http://dspace.azti.es/handle/24689/642
ISSN: 0027-8424
Funder: European Union [MEST-CT-2005-019678]
Xunta de Galicia, Spain
Natural Environment Research Council of Canada
United Kingdom's Department for the Environment, Food, and Rural Affairs [M1205]
Appears in Publication types:Artículos científicos



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