Estimating the historic size and current status of the Kemp's ridley sea turtle (<i>Lepidochelys kempii</i>) population

Bevan, Elizabeth; Wibbels, Thane; Najera, Blanca M. Zapata; Sarti, Laura; Martínez, Francisco; Cuevas, J. M.; Gallaway, Benny J.; Peña, Luis Jaime; Burchfield, Patrick M.

doi:10.1002/ecs2.1244

Cited by 27 publications

(24 citation statements)

References 3 publications

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“…Parameters A and N 0 were assumed to be equal for the decline and increase phases of the logistic model. Both models estimated the year in which the lower asymptote (A) occurred to be around 1985 (Table 1), which is consistent with previous views that the index reached its lowest level in 1985 (Byles 1993;Caillouet 2014;Bevan et al 2016;Caillouet et al 2016). Both models were used to extrapolate N t backward from 1966 to 1945 and forward from 2009 to 2017.…”

Section: Pre-2010 Density Dependence Of the Indexsupporting

confidence: 88%

“…Interestingly, the upper asymptote preceding the decline was near the 25,000-nest level that is assumed equivalent to the Kemp's ridley downlisting criterion of 10,000 females nesting in a season (NMFS et al 2011). This asymptote (K) was also the same order of magnitude as the number of nests estimated by Bevan et al (2016) for the 1947 arribada, namely, approximately 26,916. Density-dependent periods estimated by the logistic model occurred before 1962 and after 2004 (Fig.…”

Section: Pre-2010 Density Dependence Of the Indexsupporting

confidence: 66%

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Did Declining Carrying Capacity for the Kemp's Ridley Sea Turtle Population Within the Gulf of Mexico Contribute to the Nesting Setback in 2010−2017?

Caillouet¹,

Raborn

Shaver³

et al. 2018

Chelonian Conservation and Biology

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Section: Pre-2010 Density Dependence Of the Indexsupporting

confidence: 88%

Section: Pre-2010 Density Dependence Of the Indexsupporting

confidence: 66%

Did Declining Carrying Capacity for the Kemp's Ridley Sea Turtle Population Within the Gulf of Mexico Contribute to the Nesting Setback in 2010−2017?

Caillouet¹,

Raborn

Shaver³

et al. 2018

Chelonian Conservation and Biology

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“…Furthermore, understanding regional dietary habits may be useful for predicting catastrophic events such as harmful algae blooms that may affect turtles consuming filter-feeding tunicates (Perrault et al, 2014) or potential effects of oil spills on benthic crustaceans and other prey. Given the recent uncertain trend at nesting beaches (Bevan et al, 2016;Galloway et al, 2016), protected estuaries throughout the Gulf of Mexico and U.S. Atlantic seaboard will remain essential for sustaining the viability of the Kemp's Ridley Sea Turtle population.…”

Section: Discussionmentioning

confidence: 99%

Comparing Diets of Kemp's Ridley Sea Turtles (Lepidochelys kempii) in Mangrove Estuaries of Southwest Florida

Schmid

Tucker

2018

Journal of Herpetology

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We quantified diets of Kemp's Ridley Sea Turtles (Lepidochelys kempii) in Charlotte Harbor National Estuary, Florida, to identify possible ontogenetic variation in prey consumption, to examine the use of local prey, and to contrast the diets of conspecifics at other foraging areas. Dietary analysis was conducted by identifying prey remains recovered in 58 fecal samples from 53 turtles (24.2-63.7 cm midline straight carapace length). Turtles consumed seven prey categories: crustaceans, chelicerates, fish, sessile invertebrates, molluscs, plants/algae, and unidentified items. Spider crabs (Libinia sp.) are the dominant prey consumed in the mangrove estuary, occurring in 94.8% of fecal samples, accounting for 71.4% of dry mass, and as 76.3% in the Index of Relative Importance. We found no significant ontogenetic differences in prey composition between small (<40 cm) and large (‡40 cm) turtles, although crustaceans were more prevalent in diets of the larger turtles. The prey consumed in Charlotte Harbor differed significantly from a similar study of a nearby mangrove estuary in the Ten Thousand Islands. Sandy-Skinned Tunicates (Molgula occidentalis) were the predominant food item in the latter locale, and there were no significant ontogenetic differences in prey composition. A comparison of prey availability and use suggests that Kemp's Ridley Sea Turtles ingested the most abundant prey in the Charlotte Harbor estuary. Geographic differences in diet may reflect localized differences in use of foraging habitat and available prey, but more studies are needed on the availability, use, and selection of both habitat and prey.

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“…Kemp's ridleys declined precipitously into the 1970s before a concerted, coordinated, bi-national effort between government authorities in México and the USA established and implemented actions to address the highest impact threats: harvest of adult females and eggs and fisheries bycatch mortality 61 . Although the current Kemp's ridley population size is still a small fraction of its historical abundance 62 , these efforts saved the species from extinction and promoted a long-term population increase.…”

Section: Conclusion and Next Stepsmentioning

confidence: 99%

Enhanced, coordinated conservation efforts required to avoid extinction of critically endangered Eastern Pacific leatherback turtles

Abrego¹,

Acuña-Perales²,

Alfaro‐Shigueto³

et al. 2020

Sci Rep

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www.nature.com/scientificreports enhanced, coordinated conservation efforts required to avoid extinction of critically endangered Eastern Pacific leatherback turtles the Laúd opo network † Failure to improve the conservation status of endangered species is often related to inadequate allocation of conservation resources to highest priority issues. Eastern Pacific (EP) leatherbacks are perhaps the most endangered sea turtle population in the world, and continue on a path to regional extinction. To provide coherent, regional conservation targets, we developed a population viability analysis and examined hypothetical scenarios describing effects of conservation activities that either reduced mortality or increased production of hatchlings (or both). Under status quo conditions, EP leatherbacks will be extirpated in <60 yr. To ensure a positive, long-term population trajectory, conservation efforts must increase adult survivorship (i.e., reduce adult mortality) by ≥20%, largely through reduction of fisheries bycatch mortality. Positive trajectories can be accelerated by increased production of hatchlings through enhanced nest protection and treatment. We estimate that these efforts must save approximately 200-260 adult and subadult leatherbacks and produce approximately 7,000-8,000 more hatchlings annually. Critically, reductions in late-stage mortality must begin within 5 years and reach 20% overall within the next 10-15 years to ensure population stabilization and eventual increase. These outcomes require expanded, sustained, coordinated, high-priority efforts among several entities working at multiple scales. Fortunately, such efforts are underway.Species declines driven by human causes have been well-documented across taxonomic groups in recent decades 1 . In some cases, persistent, effective conservation efforts -often coupled with enforced legal protections -have stabilized and even begun to recover populations 2 . Among long-lived marine species such as marine mammals, turtles, birds, and elasmobranchs, there is wide variation in long-term population trends and whether conservation efforts have successfully achieved recovery goals 3-5 . For populations to recover, threats must be reduced to levels that first stabilize, then increase population abundance; however, failure to recover depleted populations often is related to insufficient (i.e., too little for too short a time period) or inefficient allocation of limited resources to conservation actions of highest potential benefit to the target population 6 .Marine turtles exemplify these issues, given their global distributions and varied conservation status among regional population segments (i.e., regional management units, RMUs; Ref. 7 ). Many RMUs within and among the seven extant marine turtle species are depleted relative to historical abundance because of human-caused mortality, namely direct harvest of turtles and their eggs and incidental capture in fisheries 8 . However, some marine turtle populations are showing signs of recovery following conservati...

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Estimating the historic size and current status of the Kemp's ridley sea turtle (Lepidochelys kempii) population

Cited by 27 publications

References 3 publications

Did Declining Carrying Capacity for the Kemp's Ridley Sea Turtle Population Within the Gulf of Mexico Contribute to the Nesting Setback in 2010−2017?

Did Declining Carrying Capacity for the Kemp's Ridley Sea Turtle Population Within the Gulf of Mexico Contribute to the Nesting Setback in 2010−2017?

Comparing Diets of Kemp's Ridley Sea Turtles (Lepidochelys kempii) in Mangrove Estuaries of Southwest Florida

Enhanced, coordinated conservation efforts required to avoid extinction of critically endangered Eastern Pacific leatherback turtles

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