Use of marine protected areas and exclusive economic zones in the subtropical western North Atlantic Ocean by large highly mobile sharks

Graham, Fiona; Rynne, Patrick; Estevanez, Maria; Luo, Jiangang; Ault, Jerald S.; Hammerschlag, Neil

doi:10.1111/ddi.12425

Cited by 68 publications

(72 citation statements)

References 69 publications

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“…The ECLSP has one of the densest populations of grouper in the Caribbean (Mumby et al 2011), likely as a result of the effective no-take reserve regulations. If conch predator populations are also thriving, including those of sharks and rays already benefiting from a Bahamian ban on harvest through some core portions of their range (Graham et al 2016), it may tip mortality rates to the point where few immature conch survive to maturity. A greatly increased mortality rate of juveniles and subadults would also likely result in a population slowly dying of old age.…”

Section: Discussionmentioning

confidence: 99%

Efficacy of an established marine protected area at sustaining a queen conch Lobatus gigas population during three decades of monitoring

Kough¹,

Cronin²,

Skubel³

et al. 2017

Mar. Ecol. Prog. Ser.

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Marine Protected Areas (MPAs) are designed to conserve and preserve the ecosystems and cultural resources of the ocean. In theory, protected populations flourish, replenish adjacent regions, and are self-sustaining. However, describing the efficacy of MPAs requires long-term monitoring. Queen conch Lobatus gigas are iconic Caribbean denizens with populations that have been decimated by overfishing and are slow to rebound due to density-dependent breeding. The Exuma Cays Land and Sea Park (ECLSP) is a well-enforced, no-take, old, and large MPA. Surveys in 1994, 2011, and 2016 were used to track changes in the abundance, size, and age structure of conch within the park. Statistical models suggested that abundances of adults in 50 km of repeated towed-observer surveys had declined by 71% in 2016 relative to 2011. Further, the remaining conch populations were associated with tidal channels, and these model results agreed with independent observations in 40 km of expanded survey area. Measurements of shell lip thickness, an estimator of relative age, showed an increase relative to 1994 with the greatest effect in 2016, indicating senescence. The ECLSP population appears to be slowly dying of old age, and an early life history process has been altered. Upstream populations have been heavily fished while habitats within the park remain productive, suggesting that low local retention and a lack of exogenous larval sources are driving the decline. A network of MPAs encompassing the entire life cycle and dispersal envelope of targeted organisms is needed for proper conch conservation. Surveys focused on tidal channels could locate candidate upstream populations of conch.

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Section: Discussionmentioning

confidence: 99%

Efficacy of an established marine protected area at sustaining a queen conch Lobatus gigas population during three decades of monitoring

Kough¹,

Cronin²,

Skubel³

et al. 2017

Mar. Ecol. Prog. Ser.

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“…Further, great hammerheads remained within relatively localized areas (e.g., Florida Keys and Daytona Beach) for extended periods of time, and made long-distance movements to and from predominant-use habitats. Graham et al (2016), using data from the same sharks with an additional six animals, found that 17.87% of their core habitat use areas were within the protected Florida state waters (5.6 km off shore in the Atlantic and 16.7 km offshore in the Gulf of Mexico), which prohibit the harvest, possession, sale and exchange of great hammerheads (Florida Fish and Wildlife Conservation Commission, 2011).…”

Section: Conservation and Management Implicationsmentioning

confidence: 99%

“…found their core habitat-use areas to be in the combined waters of Florida and U.S. exclusive economic zone (EEZ) (Graham et al, 2016). Documented movements into fronts within the Atlantic Ocean were further highlighted by Queiroz et al (2016).…”

Section: Introductionmentioning

confidence: 99%

Philopatry and Regional Connectivity of the Great Hammerhead Shark, Sphyrna mokarran in the U.S. and Bahamas

et al. 2017

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A thorough understanding of movement patterns of a species is critical for designing effective conservation and management initiatives. However, generating such information for large marine vertebrates is challenging, as they typically move over long distances, live in concealing environments, are logistically difficult to capture and, as uppertrophic predators, are naturally low in abundance. Large-bodied, broadly distributed tropical shark typically restricted to coastal and shelf habitats, the great hammerhead shark Sphyrna mokarran epitomizes such challenges. Highly valued for its fins (in target and incidental fisheries), it suffers high bycatch mortality coupled with fecundity conservative life history, and as a result, is vulnerable to over-exploitation and population depletion. Although there are very little species-specific data available, the absence of recent catch records give cause to suspect substantial declines across its range. Here, we used biotelemetry techniques (acoustic and satellite), conventional tagging, laser-photogrammetry, and photo-identification to investigate the level of site fidelity/residency for great hammerheads to coastal areas in the Bahamas and U.S., and the extent of movements and connectivity of great hammerheads between the U.S. and Bahamas. Results revealed large-scale return migrations (3030 km), seasonal residency to local areas (some for 5 months), site fidelity (annual return to Bimini and Jupiter for many individuals) and numerous international movements. These findings enhance the understanding of movement ecology in great hammerhead sharks and have potential to contribute to improved conservation and management.

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“…It seems thus unlikely that the shark had moved at superficial waters from the oceanic province for such a protracted period, as proposed by the location estimates of the UKFSST algorithm. Considering that C. leucas exhibit a clear preference for coastal habitats (Carlson et al, 2010;Hammerschlag et al, 2012;Heupel et al, 2015;Graham et al, 2016), the fact that the maximum depth registered by the transmitter (64 ± 4 m) matches the minimum depth of the continental shelf break (Martins, Coutinho, 1981) suggests that this shark moved mostly within the neritic province. Previous tracking studies on C. leucas across the oceanic realm reported movements through greater depths (122-164 m) and lower temperatures (16-21ºC) (Carlson et al, 2010;Lea et al, 2015) than the shark tracked in this study, which sustain such a hypothesis.…”

Section: Discussionmentioning

confidence: 94%

“…Even though there is no evidence that this species copulates in freshwater, parturition likely occurs in warm-water estuaries and rivers (Montoya, Thorson, 1982;Compagno et al, 2005;Pillans et al, 2006). Adult C. leucas sharks make use of shallow nearshore habitats (Brunnschweiler et al, 2010;Hammerschlag et al, 2012;Heupel et al, 2015;Graham et al, 2016), particularly in areas of high freshwater inflow, associated with an elevated productivity, where they usually exhibit some level of site fidelity (Carlson et al, 2010;Daly et al, 2014). Nevertheless, this species also undertakes coastal migrations regulated by environmental, foraging and reproductive drivers (Daly et al, 2014;Espinoza et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Bioecology and movements of bull sharks, Carcharhinus leucas , caught in a long-term longline survey off northeastern Brazil

2017

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Bioecology and movements of bull sharks, Carcharhinus leucas, caught in a long-term longline survey off northeastern BrazilYuri V. Niella 1, 2 , André S. Afonso 2 and Fábio H. V. Hazin 2 A robust understanding of habitat usage by coastal shark species, and how it overlaps with human presence in denselypopulated regions is needed to inform the development of efficient conservation strategies for these important top predators. An intensive longline survey conducted in nearshore waters off northeastern Brazil from 2004 through 2014 caught a total of 18 bull sharks (Carcharhinus leucas) (male-female ratio = 0.63:1), which can be dangerous to humans. Although most sharks were sexually mature, there was no evidence that this region could be used as a parturition or nursery area. Prey items identified in the guts of the sharks comprised teleosts, mollusks and elasmobranchs. Additionally, one satellite-tagged bull shark covered a great distance (> 3,000 km) in 75 days at liberty, making most use of shallow waters (< 20 m depth) and presumably also entering an estuarine area. Although bull sharks are not an important fishery resource in this region, such a reduced abundance coupled with its affinity for coastal and inshore habitats highlights the potential vulnerability of C. leucas to deleterious anthropic interferences off northeastern Brazil.Keywords: Drumline, Longline, Maturity status, Pop-up satellite archival tag, Recife.Um melhor entendimento sobre a utilização de hábitat das espécies de tubarões costeiros, e como ela se sobrepõe à presença humana em regiões altamente populosas, se faz necessário a fim de subsidiar o desenvolvimento de eficientes medidas de conservação para esses importantes predadores de topo. Um estudo intensivo utilizando espinhel, conduzido em águas costeiras do nordeste do Brasil entre os anos de 2004 e 2014, capturou um total de 18 tubarões cabeça-chata (Carcharhinus leucas) (proporção macho-fêmea = 0,63:1), os quais podem ser perigosos para humanos. Apesar da maioria dos tubarões estarem sexualmente maduros, não houve evidências de que essa região esteja sendo utilizada como uma área de parto ou berçário. Entre os itens alimentares identificados foram encontrados teleósteos, moluscos e elasmobrânquios. Além disso, um tubarão cabeça-chata marcado com um transmissor satélite percorreu uma grande distância (> 3.000 km) em 75 dias em liberdade, fazendo o uso de águas superficiais (< 20 m profundidade) e presumivelmente entrando em uma área estuarina. Apesar de os tubarões cabeça-chata não corresponderem a um recurso pesqueiro importante nessa região, tal reduzida abundância juntamente com a sua afinidade por hábitats costeiros reforçam a potencial vulnerabilidade de C. leucas às interferências antrópicas deletérias ao longo da costa nordeste do Brasil.

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Use of marine protected areas and exclusive economic zones in the subtropical western North Atlantic Ocean by large highly mobile sharks

Cited by 68 publications

References 69 publications

Efficacy of an established marine protected area at sustaining a queen conch Lobatus gigas population during three decades of monitoring

Efficacy of an established marine protected area at sustaining a queen conch Lobatus gigas population during three decades of monitoring

Philopatry and Regional Connectivity of the Great Hammerhead Shark, Sphyrna mokarran in the U.S. and Bahamas

Bioecology and movements of bull sharks, Carcharhinus leucas , caught in a long-term longline survey off northeastern Brazil

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