title: Population declines of tuna and relatives depend on their speed of life.
abstract: Larger-bodied species in a wide range of taxonomic groups including mammals, fishes and birds tend to decline more steeply and are at greater risk of extinction. Yet, the diversity in life histories is governed not only by body size, but also by time-related traits. A key question is whether this size-dependency of vulnerability also holds, not just locally, but globally across a wider range of environments. We test the relative importance of size- and time-related life-history traits and fishing mortality in determining population declines and current exploitation status in tunas and their relatives. We use high-quality datasets of half a century of population trajectories combined with population-level fishing mortalities and life-history traits. Time-related traits (e.g. growth rate), rather than size-related traits (e.g. maximum size), better explain the extent and rate of declines and current exploitation status across tuna assemblages, after controlling for fishing mortality. Consequently, there is strong geographical patterning in population declines, such that populations with slower life histories (found at higher cooler latitudes) have declined most and more steeply and have a higher probability of being overfished than populations with faster life histories (found at tropical latitudes). Hence, the strong, temperature-driven, latitudinal gradients in life-history traits may underlie the global patterning of population declines, fisheries collapses and local extinctions.
authors.affiliation: AZTI Tecnalia, Herrera Kaia, Portualdea z/g, Pasaia, Gipuzkoa 20110, Spain Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6 mjuan@azti.es.
authors.forename: M J
authors.initials: MJ
authors.lastname: Juan-Jordá
authors.affiliation: European Commission, Joint Research Center, Institute for the Protection and Security of the Citizen, Maritime Affairs Unit G03, Ispra 21027, Italy.
authors.forename: I
authors.initials: I
authors.lastname: Mosqueira
authors.affiliation: Teamlabs, Calle de la Colegiata 9, Madrid 28012, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Freire
authors.affiliation: Earth to Ocean Research Group, Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6.
authors.forename: N K
authors.initials: NK
authors.lastname: Dulvy
mesh_terms: D000818:Animals; D049628:Body Size; D003247:Conservation of Natural Resources; D053476:Extinction, Biological; D005398:Fisheries; D008136:Longevity; D008954:Models, Biological; D011157:Population Dynamics; D013696:Temperature; D013997:Time Factors; D014413:Tuna / Q000502:physiology*
keywords: declines; fishes; fishing mortality; life histories; scombrids; vulnerability