Environmental pollution and biodiversity: Light pollution and sea turtles in the Caribbean

It was an August afternoon in 2003 when the lights went out on Broadway, and for that matter, throughout most of the Northeast, Midwest, and Ontario—a power blackout left 50 million customers in the dark overnight. Despite complaints about the inconveniences, the stranded commuters, and the food spoilage in restaurants and markets, many city dwellers were also awed; as evening came on, they gazed upward, and between the dark skyscrapers they could see something amazing—the starry night sky. The New York Times reported spontaneous stargazing gatherings in the usually electrified cities of the Northeast.

The gut microbiota is closely linked to host nutrition, immunity, and health. Here, metagenomic analysis was conducted to elucidate the taxonomic and functional diversity of gut communities from hawksbills and green sea turtles. In terms of diversity and abundance, the gut microbiota of herbivorous green sea turtles showed a higher bacterial diversity and richness than that of hawksbills. Firmicutes dominated in all groups; however, the phylum Proteobacteria showed a higher relative abundance in hawksbills. Several metabolic pathways displayed broad prevalence and high relative abundances in the two sea turtle populations. Antibiotic resistance genes (ARGs) responsible for resistance to glycopeptide and tetracycline were the most abundant in all samples. In ARGs, the subtype macB was the most abundant in the two different sea turtle populations; however, evgS, bcrA, and efrA were more abundant in the green sea turtles, while in the hawksbills, tetT and tetB(P) were more abundant. Among mobile genetic elements (MGEs), the abundance of 16 MGE types showed a significant difference between the two sea turtle populations. MGE type transposase and plasmid were the most abundant in the two sea turtle populations. Additionally, gene functions were enriched in carbohydrate esterases, glycoside hydrolases, and polysaccharide lyases in the green sea turtles, whereas genes related to glycosyltransferases and auxiliary activities were highly abundant in hawksbills. These metagenomic profiles provide further insights into the microbial diversities of the two types of sea turtles and provide valuable information for future conservation efforts.

Geo-political genetics: Claiming the commons through species mapping

Association between nighttime artificial light pollution and sea turtle nest density along Florida coast: A geospatial study using VIIRS remote sensing data


 
 
 Sri Lanka is visited by the five of the seven living sea turtle species recorded in the world. Sea turtle populations are declining, as is their ability to perform critical services in ocean ecosystems. Some of the obvious risks faced by marine turtles in Sri Lanka include incidental bycatch, illegal egg poaching, habitat change, destruction, and natural causes such as predation and erosion. Attitudes towards conservation of turtles and underlying motives for such attitudes is a lesser researched subject in the country. The present study therefore aims at assessing the attitudes of Sri Lankans towards conservation of sea turtles. A household survey was conducted using a pre-tested questionnaire adopting simple random sampling among 1084 households across the twenty-five districts of Sri Lanka through telephone and in-person interview from December 2021 to May 2022. The socioeconomic data of respondents, membership in a wild life or environmental organizations, recreational experience of turtles were also collected. A set of statements on sea turtles were presented for which the respondents indicated their preferences. Their willingness to contribute towards conservation was also recorded. The results of the study indicate that individuals from twenty-five districts had already been exposed to a wealth of knowledge regarding marine turtles and were well-informed. There were 603 individuals from coastal districts while 481 were from non-coastal districts. The average age was 45 years while number of respondents who had a membership of any environmental related wildlife organization was 164. Seventy four percent of the sample had seen live marine turtles; 37.6% of them had seen marine turtles in zoological gardens. Majority of respondents strongly agreed that (84% on average) sea turtles are worth protecting. Forty one percent of respondents agreed that it is everyone‘s duty to ensure the existence of plants and animals for future generations, showing that respondents had bequest motive for marine turtle conservation. Majority (63.3%) of respondents strongly agreed that sea turtles have the right to exist in the environment, showing that there is a strong existence motive for the conservation of sea turtles. The study emphasize the need to better utilize the strong motives of people for sea turtle conservation efforts in Sri Lanka that requires attention of legislators and decision-makers.
 Keywords: Sea turtle, Attitudes, Conservation, Motives
 
 

Persistent Organic Pollutants and Heavy Metals in the Green Sea Turtle, Chelonia Mydas

Sea turtles disease risk analysis and discovery of the first Australian green turtle (Chelonia mydas) papillomavirus

Over exploitation of marine resources pose a threat to their population and ultimate survival. Sea turtle is one of the endangered marine species whose conservation must be taken seriously because of their economic advantages. Human interferences with sea turtle habitat and procreation process have been observed to be one of the main causes of reduction in their population. This research considers the interplay of sea turtle population and hunting for sea turtles and eggs for consumption and sales to earn a living by the coastal community dwellers in some parts of South West (SW) Nigeria. The study area is characterized by humid and hot weather, with annual temperature ranging between 26 and 34°C. More than 80 percent of the rain falls during the rainy season around (April to October).Data on field encounters with sea turtle nesting sites, hatchlings and mature adults were collected, questionnaires were administered among the coastal community dwellers. It was observed that some local community members do hunt sea turtle eggs for consumption and eating of sea turtle meat which may create reduction in sea turtle population since their process of procreation has already been tampered with. Captured sea turtles must be rescued for it to survive. More needs to be done on the levels of awareness on turtle conservation and protection. Policy monitoring and implementation on endangered species conservation must be implemented and monitored in Nigeria.

Human activities are currently threatening sea turtles at all life stages, both on nesting beaches and at sea. The debris and toxic waste dumped on the coast or at sea pollutes the sea and puts marine life in danger. In recent years, the number of global turtle population have noticeably decreased, and this is largely due to plastic pollution. However, how the sea pollution affects the sea turtles’ populations is not fully understood. Therefore, in this study, using the mathematical model, we will investigate the impact of pollution on sea turtle population. The model system is analyzed using standard mathematical techniques, including positivity of solutions and stability analysis. Our findings showed that there are two possible equilibrium points (i.e. steady-state solutions) for the model proposed, in which the stability analysis showed that only one of the solutions is asymptotically stable. Thus, the conditions of stability for both equilibrium points were also derived analytically based on their eigenvalues. As for the numerical simulations, the parameter of contamination rate is varied to investigate the effect of pollution on the population of sea turtles. The results suggested that if the contamination rate is high, then the population of sea turtles are expected to decrease and extinct approximately within 10 years. The comparison of survival and extinction of sea turtles are shown using the time series plots.

The U.S. Endangered Species Act (ESA) is a powerful environmental law protecting imperiled plants and animals, and a growing number of marine species have been protected under this law as extinction risk in the oceans has increased. Marine mammals and sea turtles comprise 38% of the 163 ESA-listed marine “species”, which includes subspecies and distinct population segments, yet analyses of recovery trends after listing are lacking. Here we gathered the best available annual abundance estimates for geographically delimited populations of all 62 marine mammal and sea turtle species listed under the ESA. Of these, we chose representative populations of species that were listed before 2012, occur and reproduce in U.S. waters, and have data of sufficient quality and timespan for trend analyses. Thus, we quantitatively analyzed population trends, magnitude of population change, and recovery status for 23 and 8 representative populations of 14 marine mammal and 5 sea turtle species, respectively. Using generalized linear and non-linear models, we found that 18 marine mammal (78%) and 6 sea turtle (75%) populations significantly increased after listing; 3 marine mammal (13%) and 2 sea turtle (25%) populations showed non-significant changes; while 2 marine mammal (9%), but no sea turtle populations declined after ESA protection. Overall, the 24 populations that increased in abundance were from species listed for 20 years or more (e.g., large whales, manatees, and sea turtles). Conservation measures triggered by ESA listing such as ending exploitation, tailored species management, and fishery regulations, and other national and international measures, appear to have been largely successful in promoting species recovery, leading to the delisting of some species and to increases in most populations. These findings underscore the capacity of marine mammal and sea turtle species to recover from substantial geographical population declines when conservation actions are implemented in a timely and effective manner.

AimHurricanes bring wind and rainfall that can have dramatic effects on coastal ecosystems, which provide important nesting locations for some migratory species. We investigated the frequency with which hurricanes impact spatially and biologically distinct sea turtle nesting populations to understand whether the reproductive biology of sea turtles can buffer population‐level impacts of these disturbances.LocationNorth‐western Atlantic and north‐eastern Pacific Oceans.MethodsHistorical hurricane paths from 1970 to 2007 were combined into a spatial layer of seasonal storm frequency, which we used to quantify the frequency of impacts on sea turtle nesting sites. This was done by comparing spatio‐temporal patterns of hurricane frequency among nesting sites used by different species and spatially/biologically distinct populations (‘regional management units’).ResultsHurricanes affected 97% of sea turtle nesting beaches (n = 2444) over four decades, and the seasonal incidence of these storms overlapped substantially with sea turtle nesting and egg incubation periods. The spatial distribution of storms, in relation to the distribution of species and regional management units, determined relative exposure to large storm events. Green (Chelonia mydas), hawksbill (Eretmochelys imbricata) and leatherback (Dermochelys coriacea) turtle nesting beaches experienced relatively frequent storms; loggerhead (Caretta caretta) and Kemp's ridley (Lepidochelys kempii) turtle nesting beaches experienced relatively fewer storms; and olive ridley turtle (Lepidochelys olivacea) nesting sites were least affected.Main conclusionsExtreme weather events are common features of coastal environments and may impact sea turtles by altering nesting habitat quality (through sand erosion and accretion) and lowering within‐season reproductive success by drowning incubating embryos or eroding nests. The unique reproductive attributes of sea turtles (i.e. individual females reproduce at 2–5‐year intervals, and when reproducing lay 2–7 clutches of c. 100 large eggs at c. 2‐week intervals) may be uniquely suited to exploiting highly disturbed nesting habitats. The impacts of hurricanes on sea turtle populations may be limited because even in severe storm seasons only a proportion of adult females are reproducing, and only those eggs incubating at the time of storm impact will be directly affected. Understanding whether the frequency of large storms influences long‐term population dynamics will aid in the development of effective local and regional management plans for sea turtle recovery efforts.

Estimating population abundance is key for species of conservation concern. This is particularly challenging for marine animals, like sea turtles, with ocean-scale distribution and migratory nature. However, sea turtles lay clutches on land where they can be easily counted; thus, clutch number has always been the most common index of population abundance. A female typically lays >1 clutch per year and does not reproduce every year. Therefore, 2 conversion factors are needed to convert the number of egg clutches to the number of adult females: the number of clutches laid by a female in a nesting season and the fraction of adult females reproducing in a season, which is linked to the breeding periodicity. The effects of breeding periodicity, probability of detection and annual survival probability on the derived adult female abundance were investigated by simulating a virtual population of adult females over a 15 yr beach monitoring period. The results indicate that current methods may greatly overestimate the abundance of sea turtle populations, especially in situations with a low detection probability, including temporary emigration. The factors involved and ways to minimize biases and errors are discussed, including a method which is easy to implement using existing datasets. A careful reassessment of current estimates of sea turtle abundance derived from nest counts and capture-mark-recapture data would be appropriate, and the potential error associated with such estimates should be considered when they are used in conservation status assessments.

Sea turtles are keystone species in marine environments due to their essential role as seagrass grazers and population regulation of jellyfish and sponges in coral reefs. However, due to their predominant presence in coastal areas, sea turtle populations face significant threats due to the impact of human activities. In this systematic review, 655 peer-reviewed publications were analyzed to assess the extent of population monitoring for all seven sea turtle species. The analyses revealed that, although population monitoring studies have increased for sea turtles in the past four decades, these have been biased towards certain species and oceanic regions. Furthermore, sea turtle population monitoring has been undertaken primarily using field-based methods, with satellite tracking and nest surveys being the most commonly used methods; however, the implementation of genetic methods for population monitoring has increased since the 2000s. Direct conservation recommendations from this study include the urgent need to establish population monitoring studies in the Critically Endangered Kemp’s ridley and hawksbill and the Data Deficient flatback. Furthermore, population monitoring programs should be implemented in Southeast Asia and Northern and Central Africa, where knowledge on sea turtle populations is still limited. Finally, due to the long-distance movements of sea turtles, we also advocate for international cooperation and collaboration of local communities to protect these ecologically important and iconic marine species.

Sea turtle populations have significantly declined in recent years due to anthropogenic causes. Historical stranding records in the Canary Islands archipelago (Spain) reveal a high frequency of Caretta caretta and Chelonia mydas strandings. Our study aims to comprehensively characterize and explore these stranding records. Additionally, we have investigated the interactions between sea turtles and the island's professional fishers, seeking insights from small-scale artisanal fishers to understand the current state of sea turtle populations. The results have shown that Tenerife stands out with the highest number of sea turtle strandings, recording 1875 strandings over a span of 23 years. The primary cause of sea turtle stranding's is the interaction with fishing gear, specifically nets and hooks. Moreover, our research has highlighted the need for improved knowledge and training on how to handle stranded sea turtles within the fishing sector. Consequently, raising awareness and implementing conservation plans for sea turtle populations in Tenerife is of outmost importance in addressing and improving the current situation.

All sea turtle species are listed on the Red List of the International Union for the Conservation of Nature due to multiple threats. Among these, disease is a frequent cause of stranded sea turtles encountered in rehabilitation centers. Since 2013, we found joint swelling in 13 sea turtles belonging to all four sea turtle species submitted to the Kélonia Sea Turtle Observatory of Reunion Island, France. Affected sea turtles presented with lameness, anorexia, and lethargy. Polyarthritis was radiographically confirmed and lesions were characterized by progressive osteolysis of bones surrounding joints. Anterior flippers were affected in all cases and posterior flippers were also involved in some cases. We isolated several bacterial agents from blood and synovial fluid. We attempted a collective treatment with injectable florfenicol, based on sensitivity results, which was continued for 4 wk and then as needed based on radiographic evolution of the lesions. Radiographic stabilization of the lesions occurred in nine of 13 cases. We reviewed environmental conditions and optimized them to minimize stress that could predispose these rehabilitated sea turtles to opportunistic infections. Handling techniques used to move sea turtles were also improved. While we can make no conclusion regarding the cause of polyarthritis in this population of sea turtles, we successfully managed this poorly described problem in a rehabilitation setting.