In-water assessments of sea turtles at Glover’s Reef Atoll, Belize

Strindberg, Samantha; Coleman, Ross A.; Perez, VR Burns; Campbell, CL; Majil, Isaias; Gibson, Janet

doi:10.3354/esr00765

Cited by 15 publications

(11 citation statements)

References 75 publications

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“…This long-term mark and recapture programme has generated essential data for understanding ecology and demographic parameters (Strindberg et al 2016), addressing a number of priority questions (Rees et al 2016, Wildermann et al 2018 for this aggregation and fitting into designed recovery plans (Marco valdi et al 2011, Roberts & Hamann 2016. Another important outcome of this programme is raising awareness for marine turtle conservation.…”

Section: Discussionmentioning

confidence: 99%

Distribution and growth rates of immature hawksbill turtles Eretmochelys imbricata in Fernando de Noronha, Brazil

Bellini¹,

Santos²,

Patrício³

et al. 2019

Endang. Species. Res.

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Knowledge of life history parameters is essential for the effective management of species of conservation concern. For migratory marine vertebrates such as hawksbill sea turtles Eretmochelys imbricata, feeding aggregations are important developmental habitats, allowing the study of population dynamics. Here, we used data from a 31 yr mark-recapture study of juvenile hawksbill sea turtles in the Fernando de Noronha Archipelago, Brazil, to estimate key demographic parameters. Turtles recruit to the neritic habitat at similar sizes to those of other Atlantic hawksbill aggregations. The curved carapace length (CCL) at the first capture ranged from 28 to 84 cm (mean ± SD: 44.6 ± 9.8 cm). Median minimum residence time of turtles captured at least twice was 3.2 yr, whilst long-term minimum residence of up to 14 yr was also observed, with turtles showing site fidelity within the archipelago. The mean size of turtles captured was constant throughout time. Turtles grew on average 3.4 ± 2.2 cm yr-1 , with a monotonic expected growth rate function generally decreasing with increasing size. At these rates, hawksbill turtles in Fernando de Noronha would need to spend ca. 14−18 yr to reach minimum adult breeding size (~74 cm CCL). This mark-recapture study has been essential to understanding the ecology and demographic parameters of this regional hawksbill turtle neritic foraging ground.

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Section: Discussionmentioning

confidence: 99%

Distribution and growth rates of immature hawksbill turtles Eretmochelys imbricata in Fernando de Noronha, Brazil

Bellini¹,

Santos²,

Patrício³

et al. 2019

Endang. Species. Res.

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“…Decades-old restrictions on turtle shell trade and fisheries designed to protect adult turtles, and more importantly, protection of turtle eggs on nesting beaches, have resulted in significant upward trends in hawksbill populations in the Caribbean ( Mazaris et al, 2017 ). One recent intensive study of sea turtle abundance over a six-year period on Glover’s Reef Atoll, Belize, estimated 1,000–2,000 juvenile hawksbills in a ∼22 km 2 fore-reef study area ( Strindberg et al, 2016 ). Time-series data on the abundance of sponge species across the Caribbean would be a useful tool for assessing shifts in sponge community structure with changes in turtle populations.…”

Section: Summary and New Research Directionsmentioning

confidence: 99%

A review of bottom-up vs. top-down control of sponges on Caribbean fore-reefs: what’s old, what’s new, and future directions

Pawlik

Loh

McMurray

2018

PeerJ

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Interest in the ecology of sponges on coral reefs has grown in recent years with mounting evidence that sponges are becoming dominant members of reef communities, particularly in the Caribbean. New estimates of water column processing by sponge pumping activities combined with discoveries related to carbon and nutrient cycling have led to novel hypotheses about the role of sponges in reef ecosystem function. Among these developments, a debate has emerged about the relative effects of bottom-up (food availability) and top-down (predation) control on the community of sponges on Caribbean fore-reefs. In this review, we evaluate the impact of the latest findings on the debate, as well as provide new insights based on older citations. Recent studies that employed different research methods have demonstrated that dissolved organic carbon (DOC) and detritus are the principal sources of food for a growing list of sponge species, challenging the idea that the relative availability of living picoplankton is the sole proxy for sponge growth or abundance. New reports have confirmed earlier findings that reef macroalgae release labile DOC available for sponge nutrition. Evidence for top-down control of sponge community structure by fish predation is further supported by gut content studies and historical population estimates of hawksbill turtles, which likely had a much greater impact on relative sponge abundances on Caribbean reefs of the past. Implicit to investigations designed to address the bottom-up vs. top-down debate are appropriate studies of Caribbean fore-reef environments, where benthic communities are relatively homogeneous and terrestrial influences and abiotic effects are minimized. One recent study designed to test both aspects of the debate did so using experiments conducted entirely in shallow lagoonal habitats dominated by mangroves and seagrass beds. The top-down results from this study are reinterpreted as supporting past research demonstrating predator preferences for sponge species that are abundant in these lagoonal habitats, but grazed away in fore-reef habitats. We conclude that sponge communities on Caribbean fore-reefs of the past and present are largely structured by predation, and offer new directions for research, such as determining the environmental conditions under which sponges may be food-limited (e.g., deep sea, lagoonal habitats) and monitoring changes in sponge community structure as populations of hawksbill turtles rebound.

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“…A variety of techniques have been used to investigate the spatial ecology of juvenile hawksbills within the Caribbean region. Several studies using in-water capture-mark-recapture (CMR) have provided important information on the population demographics, residency time, and horizontal displacement between capture events of juvenile hawks bills (van Dam & Diez 1998, Blumenthal et al 2009a, Hart et al 2013, Strindberg et al 2016. Active tracking, whereby a tagged individual is followed from a boat using a directional receiver, produced preliminary estimates of home range, whereas time− depth re corders provided data on diurnal dive patterns (van Dam & Diez 1997, 1998, Blumenthal et al 2009b, Witt et al 2010, Scales et al 2011, Berube et al 2012, Wood et al 2017.…”

Section: Introductionmentioning

confidence: 99%

Juvenile hawksbill residency and habitat use within a Caribbean marine protected area

Selby¹,

Hart²,

Smith³

et al. 2019

Endang. Species. Res.

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Understanding the spatial ecology of highly mobile marine vertebrates is necessary for informing conservation and management strategies aimed at protecting such species. Buck Island Reef National Monument (BIRNM), off the coast of St. Croix, US Virgin Islands, harbors critical foraging habitat for Critically Endangered juvenile hawksbills Eretmochelys imbricata that exhibit high site fidelity until sexual maturation. Using an array of fixed passive acoustic receivers that covered over 20.2 km 2 at its largest configuration and in-water biannual sampling, we analyzed residency patterns and habitat use of 29 hawksbills. High recapture rates allowed for longterm data collection for some individuals, with 1 individual being detected within the array 1952 d (mean ± SD: 411 ± 444 d). We used detection data to construct a resource selection function based on a generalized linear mixed model in order to determine relative habitat selection, or the use of different habitat types within an area proportional to the 'true' selection. Our covariates in the model were benthic structure, bathymetry, time of day, and year. Results showed selection by tagged individuals for shallow (< 20 m) depths in areas with high rugosity characterized by a high density of reef or rock. However, individuals also selected areas comprised primarily of sand interspersed with seagrass pastures. We also used the best supported model to predict relative selection across BIRNM and found that the total area of high relative selection decreased significantly at night. The information provided will help guide both future in-water surveys for cryptic hawksbills and management decisions about public area-use at BIRNM.

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In-water assessments of sea turtles at Glover’s Reef Atoll, Belize

Cited by 15 publications

References 75 publications

Distribution and growth rates of immature hawksbill turtles Eretmochelys imbricata in Fernando de Noronha, Brazil

Distribution and growth rates of immature hawksbill turtles Eretmochelys imbricata in Fernando de Noronha, Brazil

A review of bottom-up vs. top-down control of sponges on Caribbean fore-reefs: what’s old, what’s new, and future directions

Juvenile hawksbill residency and habitat use within a Caribbean marine protected area

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