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Study site (Bimini, Bahamas), indicating the region for the proposed MPA in north Bimini, and the location of the acoustic receivers and the sampling sites for the forage composition and distribution conducted in 2016
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Knowledge on the spatial distribution, habitat use and processes of site selection by marine turtles is fundamental to identify key habitats, critical resources, and discrete foraging aggregations for protection. This is particularly important for regions of known importance for marine turtles and where widespread habitat degradation is taking plac...
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... Bimini, Bahamas, is the only mangrove and creek habitat on the western edge of the Great Bahamas Bank and it has also been identified as an important foraging site for a resident population of juvenile green turtles (Fuentes et al., 2019;Gillis et al., 2018Gillis et al., , 2020Putillo et al., 2020). Here, we determine rookery contributions to the foraging assemblage in Bimini from 2016 through 2018 using MSA and compare our results to previous MSAs from the Bahamas (Bjorndal & Bolten, 2008). ...
... Hole have been identified as hotspots for green turtles (Fuentes et al., 2019;Gillis et al., 2018). South Bimini is an open coastal seagrass bed and Bonefish Hole, located to the North, is a mangrove tidal estuary (Gillis et al., 2018). ...
... Samples for genetic analysis were obtained across five sampling trips to Bimini consisting of two trips in 2016 (Fuentes et al., 2019;Gillis et al., 2018); one trip in 2017 (Fuentes et al., 2019;Gillis et al., 2020); and two trips in 2018 (Putillo et al., 2020). A total of 135 h of survey effort was completed across the trips to Bimini. ...
Conservation of green sea turtles (Chelonia mydas) benefits from knowledge of population connectivity across life stages. Green turtles are managed at the level of genetically discrete rookeries, yet individuals from different rookeries mix at foraging grounds; therefore, rookeries may be impacted by processes at foraging grounds. Bimini, Bahamas, hosts an important foraging assemblage, but rookery contributions to this assemblage have never been resolved. We generated mitochondrial DNA sequences for 96 foraging green turtles from Bimini and used Mixed Stock Analysis to determine rookery contributions to this population using 817 and 490 base pair (bp) rookery baseline data. The MSA conducted with 817 bp data indicated that Quintana Roo, Mexico, and Central Eastern Florida contributed most to the Bimini population. The MSA conducted with 490 bp data indicated that Southwest Cuba and Central Eastern Florida contributed the most to Bimini. The results of the second MSA differ from a previous study undertaken with 490 bp data, conducted in Great Inagua, Bahamas, which suggested that Tortuguero, Costa Rica, contributed the most to that foraging assemblage. Large credible intervals in our results do not permit explicit interpretation of individual rookery contributions, but our results do indicate substantial relative differences in rookery contributions to two Bahamian foraging assemblages which may be driven by oceanic currents, rookery sizes, and possibly juvenile natal homing. Our findings may implicate a shift in contributions to the Bahamas over two decades, highlighting the importance of regularly monitoring rookery contributions and resolving regional recruitment patterns to inform conservation.
... Makowski et al., 2006;Fuentes et al., 2019;Wildermann et al., 2019;Chambault et al., 2020;Griffin et al., 2020), subadults(Chambault et al., 2018;Doherty et al., 2020;Siegwalt et al., 2020), and adults(Whiting & Miller, 1998;Gredzens et al., 2014;Christiansen et al., 2017;Shimada et al., 2020). These studies have estimated 50%KUDs and/or minimum convex polygons (MCPs) of 0.18-4.04 ...
1. The residence, home range, and habitat use of juvenile (42.0–63.5 cm midline curved carapace length, CCL), subadult (68.6–84.6 cm CCL), and adult (81.9–104.2 cm CCL) green turtles (Chelonia mydas) was investigated using passive acoustic telemetry in Ningaloo Marine Park, north-western Australia. Eighty-one turtles ranging in size from 42 to 104 cm CCL were captured on their foraging grounds and tagged with acoustic tags.
2. Individuals were monitored for up to 913 days (range 48–913 days, median 367 days). Turtles of all sizes demonstrated very high fidelity to their foraging area. Residence declined with turtle body size and home range increased with turtle body size, with an average 50% kernel utilization distribution (KUD) area of 0.29, 0.47, and 0.57 km2 for juveniles, subadults, and adults, respectively.
3. Juveniles occurred only in shallow inshore habitat dominated by seagrass and macroalgae-covered pavement. Subadults and adults selected macroalgae-covered pavement, sandy areas of the lagoon, and macroalgae-dominated patch reefs within the lagoon.
4. At high tide, juveniles were approximately 200 m closer to the shore than at low tide, but there was no tidal pattern of space use in subadult and adult turtles.
5. Less than 5% of turtles departed the array within 6 months and there was no evidence of developmental migrations in subadults.
6. The results highlight the conservation potential for go-slow areas to minimize boat strike in areas of high turtle density, given the small and stable home ranges. Furthermore, the spatial segregation of juveniles, subadults, and adults will result in variability in the susceptibility of individuals to boat strike.
7. The influencing factors that drive the developmental migrations of turtles to consecutive habitats as they grow, as well as movement away from foraging grounds in response to changes in habitat quality, are complex. The ability of acoustic telemetry to provide long-term data on all size classes of turtles within foraging areas provides a tool to enable the long-term monitoring of turtle populations, which is required for at-risk populations and/or habitats.
... Few studies assess both sea turtle distribution and suitability of foraging areas located within protected zones (Cuevas et al., 2007;Schofield et al., 2010;Rincon-Diaz et al., 2011a, 2011b. Several studies suggest the establishment of new MPAs or the extension of existing MPAs due to sea turtle presence (Fuentes et al., 2018;Dawson et al., 2017;Hays et al., 2014;Lea et al., 2016), yet do not further assess essential habitat characteristics and the suitability of existing areas, nor do they suggest a reformation of management strategies to ensure these habitat qualities are maintained. ...
Marine protected areas (MPAs) have been established to decrease the negative impacts of human activities on important marine habitats. Several sea turtle species reside within MPAs; however, analyses of habitat suitability for sea turtles within many MPAs is typically lacking. Habitat modeling and species mapping have become essential tools in determining areas suitable for species inhabitance. MaxEnt is a popular machine-learning program that uses presence-only occurrence data and is considered the best modeling method in discriminating between suitable and unsuitable habitats. Using MaxEnt, we created species distribution models (SDMs) from presence-only occurrence points for juvenile hawksbills and three environmental variables: boat traffic intensities, prey item distributions, and benthic characterizations, within the Sandy Bay West End Marine Reserve (SBWEMR) in Roatán, Honduras. Area under the receiving operator curve (AUC) values were greater than 0.75, indicating high model accuracy. Jackknife evaluations indicated algal prey item Dictyota spp., boat traffic intensity, and Geodia neptuni sponge abundance had the greatest influence on species distribution. Areas of suitability shifted based on time of day and ranged from a low probability of hawksbill presence (0.0) to a high probability of hawksbill presence (0.8). Regardless of time of day, the SBWEMR is classified as at least moderately suitable (>0.2-0.4), with least suitable habitat (0-0.2) prevalent in the most northeastern region of the reserve. The greatest suitability (>0.6-1) was evident within the mid-region and southern most regions of the reserve. Probability of hawksbill presence increased in accordance with increasing boat traffic, although there was no clear causative relationship between the two. Although the reserve overall is mostly moderately suitable, the SBWEMR remains an important local recruitment and foraging ground for juvenile hawksbills. Hawksbills have been considered resilient, continually functioning beneath their operational limits. However, with continued global depletion of essential habitats over time and lack of effective MPA management, areas of habitat suitable for hawksbill inhabitance may decrease below levels sufficient for hawksbill presence in protected areas of the Western Caribbean.
... Information on animal space use is critical for long-term MPA effectiveness, which is a function of the extent of spatial overlap between animal space use and MPA boundaries (Kramer and Chapman, 1999;Villegas-Ríos et al., 2021). Although passive acoustic telemetry has previously been used to evaluate and improve MPA effectiveness (Bond et al., 2012;Chapman et al., 2005;Gallagher et al., 2021;Lea et al., 2016;Lee et al., 2014;Meyer et al., 2010), integrating these data with a systematic conservation planning framework that guides the design and location of reserves to meet explicit biodiversity objectives, could potentially further optimize MPA performance (Dwyer et al., 2019;Fuentes et al., 2019;Margules and Pressey, 2000). However, a lack of certainty in how to integrate these two components hampers the widespread application of such integration (Dwyer et al., 2019). ...
... We divided our study site into 1 km 2 grid cells, for a total of 180 planning units. The choice of planning unit size was based on a previously executed planning exercise to maintain consistency in recommendations (Fuentes et al., 2019). For our planning region the conservation features of interest were benthic habitats (n+p, 2015) as surrogate for species habitats and diversity, elasmobranch species space-use classes, and lemon shark nurseries. ...
... We defined four planning scenarios to investigate the design and robustness of MPAs at protecting 30% of defined conservation features, exploring two possible sets of conservation feature targets, and considered whether including the proposed NBMPA influenced spatial recommendations for future protection (Table 1; Fuentes et al., 2019). To investigate the potential effect of seasonal differences in elasmobranch space use on the reserve design solutions and determine whether seasonal time-area closures pose a better management strategy than permanent MPAs, we repeated these scenarios including the space use of elasmobranch species across the full year (scenarios 1-4), during summer only (scenarios 5-8), and during winter only (scenarios 9-12). ...
Marine protected areas (MPAs) are increasingly applied to regulate fishing and conserve marine biodiversity. Yet, MPAs are often designed without sufficient ecological knowledge of the species they are intended to protect. This is particularly relevant to large and wide-ranging marine predators including many elasmobranchs (sharks and rays), for which region-specific space-use information is limited. Further, uncertainty remains in how to integrate movement datasets with systematic conservation planning frameworks to meet explicit conservation objectives. We addressed these knowledge gaps by combining movement models, constructed from passive acoustic telemetry data for eight elasmobranch species, and systematic conservation planning to investigate the design and adequacy of MPAs in Bimini, The Bahamas. Currently, there is a proposal for a no-take MPA in North Bimini (NBMPA), although it is unclear how this MPA would benefit elasmobranch communities if or when implemented. Our results show that although the NBMPA would contribute to elasmobranch conservation, the supplementation with an additional MPA southwest of Bimini would be necessary to protect important habitats for multiple elasmobranch species. This southwestern area was highlighted as a conservation priority area of both permanent MPA designs as well as seasonal time-area closures, regardless of NBMPA implementation status and conservation targets considered in this study. Our integrative approach also demonstrates its ability to optimize MPA designs for marine predator communities, combining multi-species movement models, constructed from acoustic telemetry datasets that include space-use estimates over multiple years, with MPA optimization tools.
... Assessing the effectiveness of natural protected areas (NPAs) for the protection of marine turtles and the ecosystems associated with them has been extensively attended [93][94][95][96][97][98][99]. Some of the most sensitive foraging and residency areas for Kemp's ridley (northwestern Yucatan) and loggerhead turtles (offshore Tabasco) were the least protected by existing NPAs in the southern Gulf of Mexico. ...
Planning for marine ecosystems management demands spatially explicit information about structural and functional components, in a tradeoff between including the most taxa and keeping it functional. Sentinel, umbrella, and surrogate taxa are strategic for developing indexes that account for other associated species and contribute to a sustainable administration of our seas. Marine turtles feature the former species descriptions, and the knowledge on their ecology contributes to design conservation and restoration strategies in regions they occupy, such as the Gulf of Mexico. Several administrative tools exist to govern marine territories for biodiversity conservation, and assessing how these tools interact with the ecological vulnerability of endangered species is crucial for improving public policies. We assessed the spatial interactions among ecological sensitivity, vulnerability, and the potential impacts on four marine turtle species in the southern Gulf of Mexico and northwestern Caribbean Sea with territorial management tools (natural protected areas, marine priority sites, and ecoregions). A small percentage of the most vulnerable areas is inside natural protected areas, while marine priority sites include a higher percentage. We identified spatial covering gaps that need to be addressed to ensure the conservation and recovery of these endangered species in the Gulf of Mexico and proposed key regions for maximizing territorial conservation.
... These strategies require planning and evaluation to ensure they are reaching their intended goals (Day, 2008). The effectiveness of MPAs at protecting marine turtle habitat has been evaluated with acoustic telemetry by assessing the percentage of habitat use that occurs within current or proposed MPA boundaries (Blumenthal et al., 2009b;Carrión-Cortez et al., 2013;Lea et al., 2016;Fuentes et al., 2018;Griffin et al., 2020). Acoustic telemetry has also facilitated a multispecies approach to MPA evaluation by tracking multiple species simultaneously (Lea et al., 2016). ...
While widely applied in fisheries science, acoustic telemetry remains an underutilized method in the field of marine turtle biotelemetry. However, with the ability to provide fine-scale spatial data (tens to hundreds of meters, depending on array setup and receiver range) at a low cost, acoustic telemetry presents an important tool for obtaining key information on marine turtle ecology. We present a comprehensive and systematic review acknowledging how acoustic telemetry has been used to advance the field of marine turtle ecology and conservation. We identify the extent of current studies and discuss common and novel research approaches while addressing specific limitations of acoustic telemetry. Forty-eight studies were reviewed, representing six of the seven marine turtle species and all life stages, with most individuals identified as juveniles (45%) and hatchlings (36%). Most studies (83%) focused on the spatial distribution of marine turtles, including estimating home ranges, investigating drivers of habitat use, and identifying horizontal movement patterns and vertical space use. Additionally, acoustic telemetry has been used to study hatchling dispersal and marine turtle exposure and response to threats, as well as to monitor physiological parameters. We identified that acoustic telemetry directly or indirectly informs 60% of the top questions and research priorities related to marine turtles identified by experts in the field. With an increase in acoustic telemetry receiver networks and collaborations across taxa, the applicability of acoustic telemetry is growing, not only for marine turtles but for a wide array of marine species. Although there are limitations that need to be considered at a site/project-level, acoustic telemetry is an important, low-cost technology able to address key questions related to marine turtle ecology that can aid in their conservation, and therefore should be considered by researchers as they develop their projects.
... Defining adequate targets for migratory marine species, such as marine turtles, is challenging ( with targets for protection often related to protecting a specific proportion of a species distributional range and/or high use areas (for examples see Fuentes et al., 2019;Gerber and Heppell, 2004;Mazaris et al., 2014;Pompa et al., 2011). In the context of marine turtles, the zoning of the Great Barrier Reef Marine Park (GBRMP), is one of the few MPAs in the world which clearly states a quantifiable target for the protection of marine turtle habitat with a minimum of 20% of known foraging habitat for each occurring marine turtle species to be protected (Dryden et al., 2008). ...
... Knowledge of the spatial distribution and habitat use of species is paramount to identify key habitats, critical resources and discrete locations for the implementation of MPAs (Bailey et al., 2012;Schofield et al., 2013a;Schofield et al., 2013b;Fuentes et al., 2019). Applicability of such information is highlighted by Hays et al. (2019). ...
... In the context of marine turtles, it is crucial that as information becomes available, especially those related to their distribution, habitat use and threats, that it is considered into management plans through an adaptive management approach. In particular, conservation planning approaches that consider delineation of movements and high use areas by species of conservation concern are very useful for the prioritization of areas for protection (for examples see Mazor et al., 2016;Fuentes et al., 2019). ...
Marine protected areas (MPAs) are among the most widely used strategy to protect marine ecosystems and are typically designed to protect specific habitats rather than a single and/or multiple species. To inform the conservation of species of conservation concern there is the need to assess whether existing and proposed MPA designs provide protection to these species. For this, information on species spatial distribution and exposure to threats is necessary. However, this information if often lacking, particularly for mobile migratory species, such as marine turtles. To highlight the importance of this information when designing MPAs and for assessments of their effectiveness, we identified high use areas of post-nesting hawksbill turtles (Eretmochelys imbricata) in Brazil as a case study and assessed the effectiveness of Brazilian MPAs to protect important habitat for this group based on exposure to threats. Most (88%) of high use areas were found to be exposed to threats (78% to artisanal fishery and 76.7% to marine traffic), where 88.1% were not protected by MPAs, for which 86% are exposed to threats. This mismatch is driven by a lack of explicit conservation goals and targets for turtles in MPA management plans, limited spatial information on species' distribution and threats, and a mismatch in the scale of conservation initiatives. To inform future assessments and design of MPAs for species of conservation concern we suggest that managers: clearly state and make their goals and targets tangible, consider ecological scales instead of political boundaries, and use adaptative management as new information become available.
... Knowledge of sea turtle foraging and spatial ecology is critical to identify areas of high/potential use, assess their exposure to threats, and inform management and conservation of sea turtles (Hawkes et al., 2006;Gredzens et al., 2014;Mazor et al., 2016;Rees et al., 2016;Fuentes et al., 2019). However, sea turtle research overwhelmingly relies upon data collected from nesting sea turtles, as they are easier to encounter and sample than foraging, in-water turtles (Hamann et al., 2010;Rees et al., 2016). ...
Sea turtles are exposed to numerous threats during migrations to their foraging grounds and at those locations. Therefore, information on sea turtle foraging and spatial ecology can guide conservation initiatives, yet it is difficult to directly observe migrating or foraging turtles. To gain insights into the foraging and spatial ecology of turtles, studies have increasingly analyzed epibionts of nesting turtles, as epibionts must overlap spatially and ecologically with their hosts to colonize successfully. Epibiont analysis may be integrated with stable isotope information to identify taxa that can serve as indicators of sea turtle foraging and spatial ecology, but few studies have pursued this. To determine if epibionts can serve as indicators of foraging and spatial ecology of loggerhead turtles nesting in the northern Gulf of Mexico we combined turtle stable isotope and taxonomic epibiont analysis. We sampled 22 individual turtles and identified over 120,000 epibiont individuals, belonging to 34 macrofauna taxa (>1 mm) and 22 meiofauna taxa (63 μm–1 mm), including 111 nematode genera. We quantified epidermis δ¹³C and δ¹⁵N, and used these to assign loggerhead turtles to broad foraging regions. The abundance and presence of macrofauna and nematodes did not differ between inferred foraging regions, but the presence of select meiofauna taxa differentiated between three inferred foraging regions. Further, dissimilarities in macrofauna, meiofauna, and nematode assemblages corresponded to dissimilarities in individual stable isotope values within inferred foraging regions. This suggests that certain epibiont taxa may be indicative of foraging regions used by loggerhead turtles in the Gulf of Mexico, and of individual turtle foraging and habitat use specialization within foraging regions. Continued sampling of epibionts at nesting beaches and foraging grounds in the Gulf of Mexico and globally, coupled with satellite telemetry and/or dietary studies, can expand upon our findings to develop epibionts as efficient indicators of sea turtle foraging and spatial ecology.
... Coral reefs can be found on the western side of the island, adjacent to the Gulf Stream. Green algae and Thalassia testudinum dominant seagrass beds are found in the shallow northern, central and southern flats (Fuentes et al. 2019;Hussey 2003;Jennings et al. 2012). Red algae is found in higher concentrations in the northern estuary, Bonefish Hole ( Fig. 1; Fuentes et al. 2019). ...
... Green algae and Thalassia testudinum dominant seagrass beds are found in the shallow northern, central and southern flats (Fuentes et al. 2019;Hussey 2003;Jennings et al. 2012). Red algae is found in higher concentrations in the northern estuary, Bonefish Hole ( Fig. 1; Fuentes et al. 2019). ...
... Sites were selected from previously established habitat sampling sites as described by Hussey (2003). Percent cover for species of seagrass, sessile filter feeders (Class: Demospongiae), red and green algae was recorded at each site in four randomly placed 1-m 2 quadrats (Gillis et al. 2018;Fuentes et al. 2019). A total of 228 quadrats (228 m 2 ) of habitat were surveyed to calculate average forage group availabilities for the full extent of Bimini forage grounds. ...
Diet selection by a species is determined by comparing the consumption (i.e., use) and abundance (i.e., availability) of prey
within their area of occupancy. Because individuals commonly use only a portion of habitat available to them (e.g., a 10-ha home range within a 1000-ha foraging habitat), it is important to quantify forage availability within individuals’ home ranges and core areas, and include these availabilities when calculating diet selection. However, studies of diet selection often consider prey availability across the entire foraging habitat of a species and not within individual home ranges/core areas. Here, we explore how spatial variability in prey availability may influence the results of diet selection for juvenile green turtles, Chelonia mydas, foraging in Bimini, Bahamas. Stable isotope analysis was used to determine prey use and satellite telemetry to infer movements and forage availability for each turtle. Forage availability was assessed at three spatial scales: (1) the full
extent of the foraging area (2) across each respective individual’s 95% utilization distribution (UD), or home ranges, and (3) across each individual’s 50% UD, or core areas. Further, we compared potential differences in diet selection by using three selection indices (Ivlev’s, Johnson’s and Chesson’s). Diet selection results varied among individuals and were influenced by the spatial scale of forage items available and the index used. Diet selection variability was observed at various spatial scales and in all indices. Our results highlight the need for careful consideration of the diet selection index and the spatial scale at which prey/forage availability is considered when determining a species’ diet selection. Selecting a more sensitive index will help identify priority resources and/or habitats that are important to species, which in turn carries conservation and management implications.
... Bimini, Bahamas (25844 0 N, 79816 0 W) located on the northwest side of the Great Bahamas Bank, approximately 86 km east of Miami, Florida, US, comprises two small islands (North and South Bimini) separated by a 0.15-km wide channel (Fig. 1 Gillis et al. 2018). Green algae and turtle grass (Thalassia testudinum) are the most widely distributed green turtle forage groups throughout BH and SF, and a high concentration of red algae is found at BH (Fuentes et al. 2019). ...
... Epidermis samples (i.e., skin tissue) were collected from the dorsal surface of the turtles' necks using a sterile steel razor blade (Gillis et al. 2018). Potential green turtle forage items (Gillis et al. 2018) were collected from four randomly selected locations at each foraging ground with high turtle density (Fuentes et al. 2019; Fig. 1). Nonplant samples were preserved in dry salt, and plant samples were pressed until analysis. ...
Plasma biochemistry profiles aid health assessment of marine turtles, but knowledge of the influence of regional biological factors (e.g., habitat, diet) on marine turtle blood plasma values is limited. To investigate the influence of diet on plasma biochemistry values in juvenile green turtles ( Chelonia mydas), we used carbon and nitrogen stable isotopes to provide a quantitative estimate of forage items in green turtles feeding at two distinct areas (Bonefish Hole and South Flats) in Bimini, Bahamas. Plasma samples were obtained from 13 turtles in Bonefish Hole (a mangrove tidal estuary) and 15 turtles in South Flats (an open water seagrass bed) in 2018. All turtles appeared outwardly healthy. Sessile filter feeders contributed the largest proportion of diet in Bonefish Hole, and seagrass contributed the highest proportion of diet in South Flats. Turtles at Bonefish Hole presented significantly lower cholesterol, total protein, phosphorus, triglycerides, and aspartate transaminase compared to South Flats. Across all turtles, those feeding primarily on red algae presented the highest uric acid and alkaline phosphatase, and turtles with a seagrass-dominated diet had the highest cholesterol. Understanding dietary influence on plasma biochemistry may help explain variances seen in local health and nutritional evaluations, and the trends reported can aid the interpretation of plasma analyte values in marine turtles.
