Data_Sheet_1_Fishers' Ecological Knowledge and Stable Isotope Analysis Reveal Mangrove Estuaries as Key Developmental Habitats for Critically Endangered Sea Turtles.docx

Successful conservation of endangered, migratory species requires an understanding of habitat use throughout life stages. When dedicated scientific studies are difficult to conduct, local expert knowledge can provide crucial baseline data to guide study design and aid data interpretation. In 2008, fishers in El Salvador demonstrated that eastern Pacific hawksbill sea turtles (Eretmochelys imbricata)—a population conservation biologists considered virtually extirpated—use mangrove estuaries as nesting habitat rather than open-coast beaches used by hawksbills in other regions. We confirmed and amplified this observation by using fishers' ecological knowledge to guide biological sampling for stable isotope analysis to assess if eastern Pacific hawskbills use mangrove-dominated estuaries as developmental habitats. We found that immature hawksbills experience a pelagic stage and then recruit to estuaries at ~37 cm curved carapace length, where they increase reliance on estuarine resources until they approach adult sizes. This life history strategy makes them especially vulnerable to in-water nearshore threats, and necessitates targeted expansion of conservation efforts throughout the eastern Pacific. Our analysis also provides a model for integrating traditional scientific approaches with local knowledge—a model that could yield crucial advances in other understudied regions.

成功保护濒危的迁徙物种，需对栖息地利用情况在其生命周期各阶段的深刻理解。当进行专门的科学研究变得困难时，当地专家的知识能够提供至关重要的基础数据，以指导研究设计并辅助数据解读。2008年，萨尔瓦多的渔夫们展示了东太平洋棱皮龟（Eretmochelys imbricata）——这一种群被保护生物学家认为几乎灭绝——利用红树林河口作为产卵栖息地，而非其他地区棱皮龟所使用的开放式海岸沙滩。我们通过运用渔民的生态知识来引导生物采样，进行稳定同位素分析，以评估东太平洋棱皮龟是否将红树林主导的河口作为发育栖息地，从而证实并强化了这一观察。我们发现，未成熟的棱皮龟经历一段浮游阶段，随后在约37厘米的曲甲长度时加入河口，在那里它们对河口资源的依赖性逐渐增加，直至接近成年体形。这种生命历史策略使它们特别容易受到近岸水域威胁，并要求在东太平洋范围内有针对性地扩大保护努力。我们的分析还提供了一个将传统科学方法与地方知识相结合的模型——这一模型可能在其他研究不足的地区带来关键的进步。