Sexual maturity in western Atlantic bluefin tuna

Heinisch, Gilad; Rosenfeld, Hanna; Knapp, Jessica M.; Gordin, H.; Lutcavage, Molly E.

doi:10.1038/srep07205

Cited by 24 publications

(15 citation statements)

References 57 publications

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“…Evidence of BFT reproduction taking place in a third, previously undocumented spawning area in the Slope Sea (western Atlantic Ocean) has been provided by multiple sources (Baglin, 1976;Goldstein, Heppell, Cooper, Brault, & Lutcavage, 2007;Heinisch, Rosenfeld, Knapp, Gordin, & Lutcavage, 2014;Mather, Mason, & Jones, 1974, 1995; however, the extent to which this occurs remains unknown. Recently, Richardson et al (2016)…”

Section: Evidence Of Mixingmentioning

confidence: 99%

Spatial dynamics and mixing of bluefin tuna in the Atlantic Ocean and Mediterranean Sea revealed using next‐generation sequencing

Puncher

Cariani

Maes

et al. 2018

Molecular Ecology Resources

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The Atlantic bluefin tuna is a highly migratory species emblematic of the challenges associated with shared fisheries management. In an effort to resolve the species' stock dynamics, a genomewide search for spatially informative single nucleotide polymorphisms (SNPs) was undertaken, by way of sequencing reduced representation libraries. An allele frequency approach to SNP discovery was used, combining the data of 555 larvae and young-of-the-year (LYOY) into pools representing major geographical areas and mapping against a newly assembled genomic reference. From a set of 184,895 candidate loci, 384 were selected for validation using 167 LYOY. A highly discriminatory genotyping panel of 95 SNPs was ultimately developed by selecting loci with the most pronounced differences between western Atlantic and Mediterranean Sea LYOY. The panel was evaluated by genotyping a different set of LYOY (n = 326), and from these, 77.8% and 82.1% were correctly assigned to western Atlantic and Mediterranean Sea origins, respectively. The panel revealed temporally persistent differentiation among LYOY from the western Atlantic and Mediterranean Sea (F = 0.008, p = .034). The composition of six mixed feeding aggregations in the Atlantic Ocean and Mediterranean Sea was characterized using genotypes from medium (n = 184) and large (n = 48) adults, applying population assignment and mixture analyses. The results provide evidence of persistent population structuring across broad geographic areas and extensive mixing in the Atlantic Ocean, particularly in the mid-Atlantic Bight and Gulf of St. Lawrence. The genomic reference and genotyping tools presented here constitute novel resources useful for future research and conservation efforts.

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Section: Evidence Of Mixingmentioning

confidence: 99%

Spatial dynamics and mixing of bluefin tuna in the Atlantic Ocean and Mediterranean Sea revealed using next‐generation sequencing

Puncher

Cariani

Maes

et al. 2018

Molecular Ecology Resources

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“…The primary support for this hypothesis came from an exploratory longline cruise in this area from June to July 1957 that found bluefin tuna in spawning condition (10,17). Recent reproductive studies on adjacent foraging grounds in the Gulf of Maine (11,12), electronic tagging data analyses (2,4), and energetic modeling studies (9) provided further circumstantial evidence for spawning in this area. However, targeted surveys for bluefin tuna larvae in the Slope Sea were never performed, and most research over the past few decades has dismissed the idea that substantial levels of spawning occur in the western Atlantic outside of the Gulf of Mexico.…”

Section: Significancementioning

confidence: 99%

“…First, the western Atlantic bluefin tuna stock assessment should use a younger age at maturity (11). Lowering the age at maturity will increase estimates of spawning stock biomass and will likely lead to higher estimates of sustainable fishing mortality rates (14,29,30).…”

Section: )mentioning

confidence: 99%

“…This contradiction has been attributed to fish not maturing until an older age than assumed in the assessment (age at 50% maturity: eastern fish, 6-10 y; western fish, 14-16 y) or not spawning every year (6)(7)(8). Alternatively, energetic and life history modeling (9), reproductive studies (10)(11)(12), and analyses of tag data (3,4) provide evidence for undocumented spawning grounds, and an age at 50% maturity of 4-5 y throughout the Atlantic. These two depictions of bluefin tuna life history have vastly different implications for management.…”

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confidence: 99%

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Discovery of a spawning ground reveals diverse migration strategies in Atlantic bluefin tuna (Thunnus thynnus)

Richardson

Marancik

Guyon

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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123

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Atlantic bluefin tuna are a symbol of both the conflict between preservationist and utilitarian views of top ocean predators, and the struggle to reach international consensus on the management of migratory species. Currently, Atlantic bluefin tuna are managed as an early-maturing eastern stock, which spawns in the Mediterranean Sea, and a late-maturing western stock, which spawns in the Gulf of Mexico. However, electronic tagging studies show that many bluefin tuna, assumed to be of a mature size, do not visit either spawning ground during the spawning season. Whether these fish are spawning in an alternate location, skip-spawning, or not spawning until an older age affects how vulnerable this species is to anthropogenic stressors including exploitation. We use larval collections to demonstrate a bluefin tuna spawning ground in the Slope Sea, between the Gulf Stream and northeast United States continental shelf. We contend that western Atlantic bluefin tuna have a differential spawning migration, with larger individuals spawning in the Gulf of Mexico, and smaller individuals spawning in the Slope Sea. The current life history model, which assumes only Gulf of Mexico spawning, overestimates age at maturity for the western stock. Furthermore, individual tuna occupy both the Slope Sea and Mediterranean Sea in separate years, contrary to the prevailing view that individuals exhibit complete spawning-site fidelity. Overall, this complexity of spawning migrations questions whether there is complete independence in the dynamics of eastern and western Atlantic bluefin tuna and leads to lower estimates of the vulnerability of this species to exploitation and other anthropogenic stressors.ichthyoplankton | Scombridae | large pelagic fish | pop-up satellite archival tag | population structure L ong-distance migrations pose a unique challenge to fisheries management, as conservation actions taken on a regional scale can be undermined if less stringent measures are implemented across other parts of the migratory pathway. Few species exemplify this problem better than Atlantic bluefin tuna (Thunnus thynnus). This species is harvested by the fisheries of over 20 nations, from the tropics to subarctic and coastal to international waters. Contentious international disputes have persisted for decades over how many bluefin tuna to harvest and how to allocate catch among nations. By the start of the 21st century, intense fishing pressure had driven this species to historically low population levels, a decline that has since reversed as fishing mortality has decreased under stricter management (1). However, despite this recent positive trend, many challenges remain in developing an ecologically sustainable fishery for bluefin tuna that also provides economic and social benefits to the fishing communities throughout its range. Among the most prominent of these challenges is the need for stock assessment models and management regulations that better account for the complex movements of this species.The movements of Atlantic bluefin t...

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“…The hypothesis that western Atlantic bluefin tuna mature at the age of 9 y or older is refuted by direct reproductive studies. We encourage those individuals interested in determining the value of this evidence to read the maturity studies cited in our work (4,5), as well as the study by Mather et al (6), rather than relying on the edited quote in the letter of Safina (2). Previously, the absence of younger fish (<9 y of age) in the Gulf of Mexico (i.e., the only known spawning ground) was used as indirect evidence for an older age at maturity and to question the direct reproductive studies (7,8).…”

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confidence: 99%

Reply to Safina and Walter et al.: Multiple lines of evidence for size-structured spawning migrations in western Atlantic bluefin tuna

Richardson

Marancik

Guyon

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

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Sexual maturity in western Atlantic bluefin tuna

Cited by 24 publications

References 57 publications

Spatial dynamics and mixing of bluefin tuna in the Atlantic Ocean and Mediterranean Sea revealed using next‐generation sequencing

Spatial dynamics and mixing of bluefin tuna in the Atlantic Ocean and Mediterranean Sea revealed using next‐generation sequencing

Discovery of a spawning ground reveals diverse migration strategies in Atlantic bluefin tuna (Thunnus thynnus)

Reply to Safina and Walter et al.: Multiple lines of evidence for size-structured spawning migrations in western Atlantic bluefin tuna

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