Mercury isotope clocks predict coastal residency and migration timing of hammerhead sharks
نویسندگان
چکیده
The management of migratory taxa relies on the knowledge their movements. Among them, ontogenetic habitat shift, from nurseries to adult habitats, is a behavioural trait shared across marine allowing resource partitioning between life stages and reducing predation risk. As this movement consistent over time, characterizing its timing critical implement efficient plans, notably in coastal areas mitigate impact fisheries juvenile stocks. In Mexican Pacific, use smooth hammerhead shark (Sphyrna zygaena) poorly described, while species heavily harvested. Given large uncertainties associated with out-migration nursery grounds offshore waters prior reproductive maturity, more precise assessment movements needed. Photochemical degradation mercury imparts mass-independent isotope fractionation (?199Hg) which can be used discriminate neonate shallow habitats deep foraging patterns late juveniles. Here, we present application muscle ?199Hg as molecular clocks predict shifts by sharks, based isotopic compositions at initial arrival turnover rate. We observed decreases values body length, reflecting increasing reliance mesopelagic prey age. Coastal residency estimates indicated that sharks utilize resources for 2 years migration, suggesting prolonged these ecosystems. Policy implications. This study demonstrates how stable isotopes implemented complementary tool stock predicting animal migration—a key aspect conservation taxa. fishing pressure occurs depleting Consequently, decision support tools are imperative effectively maintaining early stage population levels time. finding extensively rely highly fished after parturition supports relevance establishing size limit current temporal closure could lack efficiency species.
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ژورنال
عنوان ژورنال: Journal of Applied Ecology
سال: 2023
ISSN: ['0021-8901', '1365-2664']
DOI: https://doi.org/10.1111/1365-2664.14384