Nation-wide assessment of the distribution and population size of the data-deficient nurse shark (Ginglymostoma cirratum)

Garzon, Francesco; Graham, Rachel T.; Baremore, Ivy E.; Castellanos, Dan; Salazar, Hilmar; Xiu, Cynthia; Seymour, Zeddy; Witt, Matthew J.; Hawkes, Lucy A.

doi:10.1371/journal.pone.0256532

Cited by 5 publications

(3 citation statements)

References 49 publications

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“…Intensive shark fisheries began in the 1980s in Panamá, first as incidental catches before industrializing and expanding in line with technological advancements, coupled with the increasing global pressure on fisheries [56]. Sharks became a targeted and species-directed industry, and a new source of protein, substantially increasing landings for their fins, meat, and other shark-derived products, such as liver oil and skin [87][88][89][90]. Of note, research has confirmed that 96% of captured Sphyrnidae (hammerheads) in Panamá are either "newborn or juveniles" [91,92].…”

Section: Case Study: Panamámentioning

confidence: 99%

Beyond Protection: Recognizing Nature’s Rights to Conserve Sharks

Bustamante¹

2023

Sustainability

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This paper blends conservation science with legal and policy analysis to assess the primary threats to global shark populations and explores innovative approaches to conservation building upon the philosophy of Earth law, including the Rights of Nature legal framework. Using a case study of Panamá’s national Rights of Nature law, this paper highlights approaches to improve the protection and restoration of shark populations and their habitats. By examining the ecological, social, and economic aspects of conservation holistically, this study offers an interdisciplinary perspective on the urgency for shark protection and presents Rights of Nature as a valuable approach to shark conservation, with potential applications to other species globally.

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Section: Case Study: Panamámentioning

confidence: 99%

Beyond Protection: Recognizing Nature’s Rights to Conserve Sharks

Bustamante¹

2023

Sustainability

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“…This species is widely distributed in the Western Atlantic and still has healthy and abundant northern populations, particularly off the coast of the USA, the Bahamas, and Belize (Carlson et al, 2021). Recently, Garzon et al (2021) presented the first national assessment of G. cirratum population size in Belize with an estimate ranging from 3,858 to 14,375 sharks. However, in Brazil, South Atlantic, it has been assigned as VU since 2004 (Brasil, 2004).…”

Section: Introductionmentioning

confidence: 99%

Evidence of the Atlantic nurse shark (Ginglymostoma cirratum) population shrink at Rocas Atoll, Southwestern Atlantic

Bettcher

Santos

Bertoncini

et al. 2023

Aquatic Conservation

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The Atlantic nurse shark, Ginglymostoma cirratum, was recently listed as Vulnerable by IUCN Red List, however, as highlighted, little is known about its populations in the Southwestern Atlantic. Therefore, population studies are essential to propose status evaluations and new conservation measures. Natural marks present on the animals' bodies are used as an alternative non‐invasive method rather than the usual tagging system for individual identification, thus avoiding the need for animal handling. This study aimed to evaluate the population size trend of G. cirratum at the Rocas Atoll Marine Biological Reserve, the only atoll located in the South Atlantic. Data were collected through underwater filming, photo‐identification, and visual censuses. Three expeditions were carried out in 2018 and the abundance of sharks was sampled in the inner part of Rocas Atoll Marine Biological Reserve. Sharks were identified individually with the aid of the software Interactive Identification System – Contour (I3S). Based on the re‐sightings of identified animals, two capture–recapture estimators of population size were used (Petersen–Bailey; Jolly–Seber). The estimates were then compared to the only previous estimate made 20 years before, which employed the same number of expeditions and estimators. A total of 139 sharks were identified from 444 sightings in 63 h of diving effort. Population estimates varied from 200 to 205 sharks, which are significantly lower than the previous estimate (339–368 sharks) made 20 years ago, suggesting a demographic decline in Southwestern Atlantic populations. Population studies and movement of G. cirratum are essential to inform the implementation of additional protective measures, including the establishment of protected corridors between marine protected areas and the recovery of G. cirratum populations. It is crucial to consider that the distribution of individuals may extend beyond the borders of the non‐take marine protected area. Therefore, the observed decline in the local population could potential indicate a broader decline across the Southwestern Atlantic.

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“…However, the specific role played by each habitat during the life cycle of the species ( i.e ., mating, feeding, and recruitment) is essential to understand the distribution patterns and advising conservation agencies towards protection measures for this species. This is particularly crucial since the same habitats that are essential to G. cirratum are those that have been threatened by urbanization and ocean warming ( Carlson et al, 2021 ; Capitani et al, 2021 ; Garzon et al, 2021 ), posing an even greater threat to this ‘vulnerable’ species. Considering (a) the challenge to obtain primary data on habitat use of such a largely distributed species, (b) habitat modification as one of the major threats to biodiversity and ecosystem functioning, (c) the conservation actions indicated for G. cirratum , and (d) the current demand for scientific data on ecosystem assessment, a literature review was carried out to provide information on ecological factors associated with the occurrence of G. cirratum populations and to point out and discuss priority areas for species conservation.…”

Section: Introductionmentioning

confidence: 99%

Habitat-use of the vulnerable Atlantic Nurse Shark: a review

Bettcher

Franco

Santos

2023

PeerJ

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Human activities have led to the loss of critical habitats for aquatic species at such an accelerated rate that habitat modification is considered a leading threat to biodiversity. Sharks and rays are considered the second most threatened group of vertebrates that have also suffered from habitat loss, especially in nursery grounds and reef-associated species. In this sense, actions toward the conservation of critical grounds for species survival are urgently needed, especially for those threatened with extinction. This study aimed to gather and provide information on the worldwide distribution and habitat association of the ‘vulnerable’ Atlantic Nurse Shark Ginglymostoma cirratum through a literature review performed at the Dimensions research database. A total of 30 studies published between 1950 and 2021 were retained since they defined at least the type of habitat in which G. cirratum was associated. Most studies covered the Floridian ecoregion, where G. cirratum is more common and abundant. Reefs, seagrass, sandy, rocky, mangrove, and macroalgae accounted for the majority of habitat associations, with a higher diversity of habitats detected within marine protected areas (MPAs). Ginglymostoma cirratum was recorded at a maximum depth of 75 m, temperatures ranging from 25 °C to 34 °C, and salinities between 31 and 38 ppt. Neonates were associated with shallower habitats (<20 m), mostly reefs, rocks, macroalgae, sandy shores, and seagrass, in an average temperature of 26 °C and salinity of 36 ppt. Breeding events and habitats were reported by 11 studies, 72.7% of them in shallow waters, mostly inside MPAs (90.9%). Our findings highlighted the key role played by MPAs in protecting essential grounds for threatened species, such as the Atlantic Nurse Shark. Major ecoregions (e.g., the Eastern Atlantic) are still underrepresented in the scientific literature as long as studies aim specifically to assess G. cirratum habitat association. Thus, further insights into the essential habitats needed to conserve the Atlantic Nurse Shark can still emerge from future studies. Considering the recent IUCN extinction risk status change in G. cirratum (i.e., Data Deficient to ‘Vulnerable’), new conservation measures that integrate habitat protection and management are urgently needed and should consider the data collected herein.

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Nation-wide assessment of the distribution and population size of the data-deficient nurse shark (Ginglymostoma cirratum)

Cited by 5 publications

References 49 publications

Beyond Protection: Recognizing Nature’s Rights to Conserve Sharks

Beyond Protection: Recognizing Nature’s Rights to Conserve Sharks

Evidence of the Atlantic nurse shark (Ginglymostoma cirratum) population shrink at Rocas Atoll, Southwestern Atlantic

Habitat-use of the vulnerable Atlantic Nurse Shark: a review

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