Ria Formosa was once home to the largest population of CITES-protected seahorses in the world, but recent surveys suggest a decline of almost 95% over the past decade, a dramatic population collapse attributed to a combination of habitat loss and coastal warming. Analyses of genetic diversity in archived material collected over this period will allow the Aquatic Research and Environmental Assessment Center (AREAC) of CUNY Brooklyn College to determine whether census data accurately reflect population collapse, an event with consequences for long-term population viability. This study will critically evaluate the role of census data in the monitoring of nearshore aquatic species, a key component in the evaluation of marine protected areas.

AREAC will use genetic data of archival material to trace demographic changes in the Ria Formosa population before, during, and after the apparent population bottleneck, in an explicit test of the hypothesis that census data accurately reflect population-level declines. Seahorse species are excellent models for understanding the population and genetic dynamics of localised nearshore populations, due to their relatively short ichthyoplanktonic stage (Foster and Vincent 2004), and small adult home ranges (Curtis 2004), both of which act to restrict gene flow among populations (Woodall 2009).

Specific Aims:

To track temporal fluctuations in genetic diversity in H. guttulatus across a period of climate warming.

To correlate reductions in census size across the study period with fluctuations in genetic structure and diversity.

To infer the potential influence of immigration from neighbouring populations on local demography.

To evaluate the value of coastal population surveys as proxies for population genetic analyses of diversity.