Collapse and Conservation of Shark Populations in the Northwest Atlantic

Baum, Julia K.; Myers, Ransom A.; Kehler, Daniel G.; Worm, Boris; Harley, Shelton J.; Doherty, Penny A.

doi:10.1126/science.1079777

Cited by 974 publications

(871 citation statements)

References 13 publications

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“…Depletion of top oceanic predators is a pressing global concern, particularly among sharks because they are slow reproducers (Baum et al 2003;Dulvy et al 2008). White sharks have been listed for international protection under the Convention on International Trade in Endangered Species (CITES) and the World Conservation Union (IUCN, Category VU A1cdþ2cd) (Dulvy et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Philopatry and migration of Pacific white sharks

et al. 2009

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Advances in electronic tagging and genetic research are making it possible to discern population structure for pelagic marine predators once thought to be panmictic. However, reconciling migration patterns and gene flow to define the resolution of discrete population management units remains a major challenge, and a vital conservation priority for threatened species such as oceanic sharks. Many such species have been flagged for international protection, yet effective population assessments and management actions are hindered by lack of knowledge about the geographical extent and size of distinct populations. Combining satellite tagging, passive acoustic monitoring and genetics, we reveal how eastern Pacific white sharks ( Carcharodon carcharias ) adhere to a highly predictable migratory cycle. Individuals persistently return to the same network of coastal hotspots following distant oceanic migrations and comprise a population genetically distinct from previously identified phylogenetic clades. We hypothesize that this strong homing behaviour has maintained the separation of a northeastern Pacific population following a historical introduction from Australia/New Zealand migrants during the Late Pleistocene. Concordance between contemporary movement and genetic divergence based on mitochondrial DNA demonstrates a demographically independent management unit not previously recognized. This population's fidelity to discrete and predictable locations offers clear population assessment, monitoring and management options.

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Section: Introductionmentioning

confidence: 99%

Philopatry and migration of Pacific white sharks

et al. 2009

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“…While samples of a larger number of individuals and localities will be necessary for a more reliable characterisation of the population dynamics of this species, the levels of genetic variability and structuring of stocks recorded here indicate an urgent need for the implementation of conservation and management measures in order to protect and consolidate these populations. Many different fish species present clear signs of decline in abundance, which includes many different sharks (Baum et al, 2003). Therefore, more effective controls of fishery activity are essential here, but the preservation of mangrove habitats and shoaling areas will be equally important for the long-term conservation of the species.…”

mentioning

confidence: 99%

Genetic characterisation of populations of the critically endangered Goliath grouper ( Epinephelus itajara, Serranidae) from the Northern Brazilian coast through analyses of mtDNA

Silva-Oliveira¹,

Rêgo²,

Schneider³

et al. 2008

Genet Mol Biol

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The Goliath grouper (Epinephelus itajara) is one of the most endangered species of fish of the subfamily Epinephelinae. Slow to develop and mature, and dependent on mangrove habitats for breeding, the species also suffers intense harvesting, which has reduced drastically in numbers in many areas. To contribute to the understanding of the characteristics of E. itajara populations, we conducted a molecular genetics study of the species, focusing on populations from the Northern Brazilian coast. The mtDNA control region (D-loop) of 116 individuals from five localities (Bragança, Ajuruteua, Parnaíba, Fortaleza and Natal) was analysed, and a sequence of 499 base pairs identified. Analyses of the sequences indicated that genetic variability was generally lower in E. itajara than in other endangered species of the genus. AMOVA found no significant grouping structure among the populations. Nested Clade Analysis revealed a significant association between genetic variability and geographic distribution among only three populations (Ajuruteua, Parnaíba and Natal). Genetic diversity was higher in populations from the Amazon region, which may be related to the better conservation of mangrove habitats in this area. Therefore, the present study could be used for the implementation of conservation and management measures in order to protect and consolidate these populations.

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“…In the case of the US fleet, which has a reduced spatial overlap with the other fleets, the high proportion of sailfish may be related to the specific areas of operation, concentrating fishing efforts in the Gulf of Mexico, North Caribbean and surroundings of Florida (Baum et al 2003).…”

Section: Discussionmentioning

confidence: 99%

Proportions of Atlantic sailfish (Istiophorus platypterus) and spearfish (Tetrapturus pfluegeri) caught in tuna longline fisheries

Medeiros-Silva

Andrade

2016

Int Aquat Res

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The reliability of estimations of catches of pelagic longline fisheries is especially worrying in the case of non-target species such as the sailfish (Istiophorus platypterus) and spearfish (Tetrapturus pfluegeri), because they are often recorded aggregated in onboard maps. For this reason, generalized linear models were used to identify a number of important explanatory variables and their effect on sailfish and spearfish proportions. The response variable (number of sailfish in the aggregate capture) is assumed as binomial using the logit link function. The explanatory variables used were foram year, qrt (quarter), fleet, de (distance from equator) and d (distance from areas above sea level). The selected models showed that the equatorial and coastal regions presented higher densities or catchabilities of sailfish when compared to spearfish, as in the case for fleets of China Taipei and the United States. The lowest mean proportion of sailfish [sailfish/ (sailfish ? spearfish)] of the third quarter were driven mostly by the low estimations calculated for Japan and Brazil.

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Collapse and Conservation of Shark Populations in the Northwest Atlantic

Cited by 974 publications

References 13 publications

Philopatry and migration of Pacific white sharks

Philopatry and migration of Pacific white sharks

Genetic characterisation of populations of the critically endangered Goliath grouper ( Epinephelus itajara, Serranidae) from the Northern Brazilian coast through analyses of mtDNA

Proportions of Atlantic sailfish (Istiophorus platypterus) and spearfish (Tetrapturus pfluegeri) caught in tuna longline fisheries

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