George Whitman Matthew J. Young Rachel C. Johnson Frederick V. Feyrer 2019 <div class="journal-abstract green-item"><p>Identification of habitats responsible for the successful production and recruitment of rare migratory species is a challenge in conservation biology. Here, a tool was developed to assess life stage linkages for the threatened potamodromous cyprinid Clear Lake hitch<span>&nbsp;</span><i>Lavinia exilicauda chi</i>. Clear Lake hitch undertake migrations from Clear Lake (Lake County, CA, USA) into ephemeral tributary streams for spawning. An aqueous isoscape of strontium isotopic ratios (⁸⁷Sr/⁸⁶Sr) was constructed for Clear Lake and its watershed to trace natal origins and migration histories of adult recruits. Aqueous<span>&nbsp;</span>⁸⁷Sr/⁸⁶Sr differentiated Clear Lake from 8 of 10 key tributaries and clustered into 5 strontium isotope groups (SIGs) with 100% classification success. Otolith<span>&nbsp;</span>⁸⁷Sr/⁸⁶Sr showed all five groups contributed variably to the population. The age at which juveniles migrated from natal streams to Clear Lake ranged from 11 to 152 days (mean&nbsp;±&nbsp;s.d., 43&nbsp;±&nbsp;34 days) and was positively associated with the permanency of natal habitat. This information can be used by resource managers to develop conservation actions for Clear Lake hitch. This study demonstrates the utility of strontium isotopes in otoliths as a tool to identify important freshwater habitats occupied over the lifespan of an individual that would otherwise be challenging or impossible to trace with other methods.</p></div> application/pdf 10.1071/MF18264 en CSIRO Publishing Strontium isotopes reveal ephemeral streams used for spawning and rearing by an imperiled potamodromous cyprinid--Clear Lake hitch Lavinia exilicauda chi article