Wherever land and sea meet, coastal communities have long depended on harvesting fish and shellfish for food and welfare. However, each local population of the coastal marine species we harvest itself depends on other populations, because replenishment of a population only occurs through the arrival of microscopic larvae after they were spawned and then dispersed in the open ocean for weeks to months. The long dispersal period of marine larvae can generate significant levels of “connectivity” -- and dependence -- among distant populations.

The first phase of my Ph.D. research focused on estimating the strength of connectivity among fishery areas in order to infer their dependence on each other for population replenishment. Genetic similarities among populations of the same species helped me estimate how frequently they exchange larvae, as well as enabled me to identify the source population from which settling larvae were spawned prior to dispersal. I focused on population connectivity within and among three main management jurisdictions in California (central and southern coastal areas, and throughout the Channel Islands), as well as across the California, U.S. – Baja, Mexico international border. I assessed the patterns of population connectivity in four species: Kellet's whelk, Spiny Lobster, California sheepshead and kelp bass, with particular focus on Kellet's whelk.

In the second phase of my Ph.D. research I used mathematical modeling of coupled biological-economic dynamics to evaluate the consequences of fish population connectivity on fisheries management. I focused on how understanding the levels of connectiviy and dependency among populations guides the optimal design of marine protected areas (no fishing zones) along the coastline for best promoting both species conservation and productive fisheries in the region.