ISTS Symposium43 Program/Agenda

Sandy beaches are highly dynamic ecosystems and represent key habitats for sea turtle breeding. However, nesting beaches are subject to constant erosion processes produced by high tides, storms, and rising sea levels, which results in nesting area losses and reduced clutch survival. Therefore, it is important to evaluate and quantify the occurrence of erosion over time to understand its potential impacts on sea turtle nesting populations. With this aim, we used publicly available satellite imagery to evaluate changes in shoreline position over 40 years on several important sea turtle nesting beaches in North Pacific Costa Rica. Our results showed that beaches in the North Pacific have lost suitable nesting areas in the last decades. The erosion rate varied between the studied beaches and within each beach, suggesting a differential level of risk for sea turtle clutches. Given the current rates of sea level rise, higher extreme storm frequency, and the constant development pressure, beach erosion could be exacerbated in the region. Shoreline data is key to evaluating these changes and also to predict the potential different effects on each sea turtle nesting beach. Publicly available resources, such as satellite imagery, can help to fill in existing data gaps on erosion long-term trends and contribute to the conservation management of sea turtles.

Climate change and human activity pose many different challenges to sea turtles, including the flooding and erosion of their nesting beaches. The latter closely parallel issues studied and monitored by coastal scientists—for example high water level events, beach groundwater dynamics, or structural beach erosion due to a combination of sea level rise and human infrastructure (coastal squeeze). Methods and tools used in coastal science therefore hold significant potential for sea turtle conservation, specifically coastal monitoring and modeling. These are critical in the design and assessment of potential nature-based solutions that mitigate coastal threats to nesting beaches and might even help expand global nesting habitats. Examples of such solutions may include turtle-friendly beach nourishments, artificial reefs, and coastal vegetation aimed at reducing erosion and flooding. Despite these overlaps, collaboration between the scientific sea turtle and coastal communities remains limited.

Monitoring nearshore hydrodynamics and beach groundwater can help understand the processes behind the repeated flooding of turtle nests on the beach. Long-term beach monitoring and coastal remote sensing tools (e.g., satellite-derived shoreline data) can provide information on how nesting beaches have evolved over the past decades and continue to change today, even in remote areas. Such monitoring efforts are essential for informing predictive coastal models, which can simulate how nesting beaches might respond to environmental shifts (e.g., sea level rise and intensifying storms) and assess the impact of potential nature-based solutions. For example, many studies have assessed the impact of sea level rise on turtle nesting beaches by combining a higher mean sea level with a digital elevation model of the beach. However, beach response to sea level rise depends on a complex interplay of many different variables, and therefore requires complex models to predict. Combined with data science and machine learning techniques, these models can also help upscale findings from local case studies to more regional scales.

Here, we present an overview of work conducted over the past four years, where coastal monitoring and modeling techniques were employed to aid sea turtle conservation science. We share findings from extensive field campaigns monitoring hydrodynamics and groundwater levels at nesting beaches in two contrasting coastal environments (Texas, USA, and Ostional, Costa Rica). Additionally, we demonstrate how large-scale coastal datasets, combined with machine learning, were used to (1) identify patterns in the global distribution of turtle nesting; and (2) detect beach evolution trends at several nesting hotspots around the world using satellite-derived shorelines. Through these examples, we aim to inspire more interdisciplinary collaboration by bridging the gap between sea turtle biology and coastal dynamics and showcasing how coastal monitoring and modeling tools can be effectively leveraged in sea turtle conservation.

Animal tracking is often the only way to link impacts of various threats to widely distributed marine megafauna populations. The assessment of potential impacts from those threats requires a description of overlapping distributions between animal populations and dire conditions threatening their survival. The implementation of satellite telemetry and remote sensing have increased our understanding of the spatial ecology of marine animals. Despite their broad distribution, green turtle (Chelonia mydas) populations display evidence of a distinct long-term fidelity to nesting areas. Such fidelity increases the vulnerability of marine turtles to anthropogenic and natural events suddenly altering and degrading key habitats. Tortuguero National Park, located on the Caribbean coast of Costa Rica, is considered the largest rookery for green turtles in the Atlantic basin. Due to different threats, including illegal harvesting across their migratory range, nesting trends for green turtles at Tortuguero have shown an significant decline over the past 15 years. In this study we estimate the inter-nesting area used by female green turtles nesting at Tortuguero, assessing the utilization of Marine Protected Areas (MPA’s) and interaction with potential local threats. Over the past 25 years we have equipped several nesting green turtles with satellite tags to study their post-nesting movements.

We assessed the inter-nesting behaviour of 45 tracked turtles nesting at Tortuguero. Using a movement-based kernel density estimator, we calculated the utilization distribution (UD) for the inter-nesting area used by green turtles from this rookery. We overlaid each UD with spatial information on maritime traffic, fisheries activities and MPA boundaries, to assess potential risks to turtles in these areas between nesting events. We found that tracked turtles spent a mean of 43 days (range: 11-98) at the inter-nesting area, measuring from tag deployment. During this period, all turtles remained close to shore (<20 km), and within the territorial waters of Costa Rica. Over 60% of the inter-nesting area used by green turtles was within Tortuguero National Park’s MPA and the Marine Management Area “Barra del Colorado”, where human activities are restricted. In direct conflict with the protection status of these management areas, turtles have been found to be harvested in these MPA’s. Our findings also uncovered that inter-nesting areas of green turtles that nest at Tortuguero expand southwards. We found that turtles are spending time around the heavy maritime traffic areas that surround the ports of Limón and Moin, where the risk of water pollution and boat strikes are constant threats for marine wildlife.

Green turtles nesting at Tortuguero face multiple threats whilst resting in inter-nesting habitats, despite the protection of important MPA’s. The effects of these threats on the green turtle population nesting at Tortuguero, Costa Rica require further exploration to inform protection agencies and policy makers in Costa Rica.

Sea turtle nesting beaches support several sea turtle life stages, including developing embryos and hatchlings (Shenoy et al., 2011; Ogello et al., 2022). Therefore, threats on nesting beaches threaten embryo development and survival and hatchling production, fitness, and survival. Potential threats include coastal development, take and trade of eggs and/or hatchlings, pollution, depredation, pathogens, environmental events such as storm surges and tidal inundation, and climate change which can lead to increased storm frequency and strength, sea-level rise, and temperature extremes (Sivakumar et al., 2016; Phillott & Kale, 2018; Ogello et al., 2022). Nest management can mitigate these threats by 1) protecting clutches in situ or ex situ; and/or 2) manipulating the incubation environment of in situ or ex situ clutches.

Decisions about if and how to manage nests are often based on the physical/biological elements of the natural habitat (e.g., flora, fauna, climate, and weather), resource availability (financial, material, or personnel), sociocultural or religious beliefs/practices, institutional practices, and/or legal or policy requirements (Shenoy et al., 2011; Sivakumar et al., 2016; Ario et al., 2018; Phillott et al., 2021; Phillott & Kale, 2022). Understanding the factors which influence decisions about management of sea turtle nests can inform resource allocation and policy instruments so that the most beneficial conservation outcome can be achieved.

We are conducting a systematic review of publications about nest management decision in the Indian Ocean and Southeast Asia (IOSEA) region to identify the ecological, economic, sociocultural, and/or institutional factors affecting nest management decisions and, by extension, hatching success across the region. The study is ongoing, and our presentation at the symposium will examine all relevant literature published to 2010-2023. We have identified 28 papers to date following standardized systematic review methodology. Data being extracted from the publications encompasses the turtle species, regional management units (RMUs), countries, primary, secondary, and tertiary decision makers, nest management decisions (eggs are unprotected in situ, protected in situ, relocated to a safer location on the beach, or relocated to a hatchery), and ecological (e.g., depredation, tidal wash), economic (e.g., tourism, take for trade), sociocultural (e.g., take for nutrition, beach recreational activities), institutional (e.g., standard practice, human resources), and other (e.g., pollution) that shape the decisions around nest-management.

Our findings will facilitate a better understanding of how implementation of known best practices in nest management is impacted by ecological, economic, sociocultural, and/or institutional factors to shape recommendations to the IOSEA Marine Turtle MoU about maximising hatchling production in RMUs in the Indian Ocean and Southeast Asia region.

Interactions between sea turtles and longline fisheries represent a significant threat to these species and their populations. Since 2006, in Reunion Island, the Kelonia Care Center has partnered with local fishermen to address this challenge. Fishermen willingly report and return bycaught turtles to Kelonia, where they receive medical treatment, and are released back into the ocean once fully recovered. Over the past 24 years, 583 turtles have been admitted to rehabilitation for various reasons, with 72% of cases directly linked to fishermen’s contributions.

In recent years, the SaveTurtleRUN project, launched as part of this initiative, has significantly increased participation among fishermen. Starting with just one captain in 2000, 81% of captains (n=43) are now actively involved. Annual training and experience-sharing sessions since 2013 have empowered fishermen with safe and adapted turtle-handling techniques. In 2024 alone, fishermen successfully released 42% of by-caught turtles (n=79) directly into the sea using specialized techniques and tools provided by the project. Additionally, 40% of them were brought back alive to the care center, while 18% were returned already dead for necropsy purposes. Fishermen also contribute valuable data on fishing practices, such as hook type and size, bait type, and GPS coordinates, enhancing scientific understanding and conservation measures.

Care centers like Kelonia serve as a vital interface, facilitating access to species typically found in challenging marine environments. This significantly enhances research opportunities by providing a unique and invaluable source of data. Particularly impacted by bycatch, loggerheads (n=318) and olive ridleys (n=23) have been central for research efforts. Beyond the monitoring required for treatment purposes (e.g., physiology, morphology, biometry), studies have also focused on satellite tagging to monitor both vertical and horizontal movements, along with analyzing diving profiles of loggerheads to better understand their foraging strategies and habitat use, genetic studies to explore population connectivity, assessments of plastic ingestion (positioning loggerheads as bioindicators for plastic pollution in the Southwest Indian Ocean), and isotopic signatures to clarify their trophic roles. These integrated approaches provide critical insights into the health and ecology of marine turtles while also helping identify emerging threats, ensuring adaptive and effective conservation strategies.

In addition, Kelonia shares its findings through initiatives that engage children and adults, raising awareness and responsibility for the marine environment. These programs are vital for sustaining long-term conservation efforts and promoting the protection of marine turtles.

This long-standing partnership demonstrates the tangible conservation benefits of interdisciplinary efforts, combining fishermen’s expertise and commitment with Kelonia’s care and scientific knowledge. It served as a potential mitigation measure for bycatch-related mortality, reflected in the decline of mortality rates among impacted loggerhead and olive ridley turtles—from 55% in the early years (n=22) to 20% in the past three years (n=112), demonstrating improved rehabilitation outcomes. Moreover, it has expanded scientific knowledge, raised public awareness, and strengthened advocacy for sea turtle conservation. Future collaborations will focus on microbiota assessments, skeletochronology, isotopic signatures, and deeper understanding of post-release survival rates following incidental catches.

Introduction
The West Africa Sea Turtle Conservation Network (WASTCON) was established in 2020 to address the urgent need for coordinated sea turtle conservation across West Africa. Supported by international partners, including Programmes de Petites Initiative (PPI), IUCN’s Central and West Africa Programme (IUCN PACO), and Sea Turtles Africa Team (RASTOMA), WASTCON unites 15 civil society organizations (CSOs) from seven countries—Benin, Côte d'Ivoire, Ghana, Gambia, Nigeria, and Togo. Its mission is to foster collaboration among CSOs, governments, and local communities to protect sea turtles through policy advocacy, conservation action, and awareness campaigns.

Coordinated Conservation Efforts
WASTCON’s key initiatives address threats like illegal poaching and bycatch by promoting sustainable fishing practices, reducing habitat destruction, and protecting nesting sites. By advocating for stronger conservation policies, the network collaborates with national governments to enhance legislation and enforcement measures. Acting as a bridge between CSOs and authorities, WASTCON supports a conducive policy environment for impactful conservation.

Key Achievements
WASTCON has made significant progress, including releasing over 50,000 hatchlings and 2,500 adult turtles through its member organizations. Its notable successes include co-organizing the African Sea Turtles Congress in Benin with RASTOMA and NASNet, which brought together 45 experts and stakeholders to discuss conservation challenges and share best practices. Additionally, WASTCON hosted webinars on datasheet harmonization, advocacy, and conflict management, involving over 100 conservation actors from West, Central, and North Africa. These initiatives have fostered regional collaboration and advanced sea turtle conservation efforts.

Challenges and Obstacles
Despite its successes, WASTCON faces significant challenges. Limited funding and the absence of salaried staff hinder its ability to organize face-to-face meetings, exchange visits, and expand programs. Many member organizations operate with constrained budgets, restricting community outreach and conservation activities. Varied legal frameworks, cultural practices such as turtle egg consumption, and weak enforcement standards across countries further complicate regional coordination.

Future Strategies
To address these challenges, WASTCON is pursuing long-term funding from international donors and strengthening partnerships with environmental organizations. Expanding community outreach and education aims to build local ownership of conservation programs, fostering lasting change at the grassroots level. The network also plans to establish a unified conservation framework for its member states, facilitating information sharing and coordinated responses. Additionally, WASTCON is intensifying its policy advocacy efforts to encourage governments to adopt stronger legal protections for sea turtles.

Conclusion
WASTCON has made significant strides in sea turtle conservation through policy advocacy, community engagement, and collaborative action. However, addressing financial constraints, enhancing regional coordination, and securing stronger legal protections are crucial to ensuring the long-term survival of sea turtles in West Africa. With sustained effort and improved resources, WASTCON is well-positioned to achieve its conservation goals.

By: Ebiegberi Henry Raynus
Secretary General – WASTCON
13th Nov. 2024