Population Genetics

Population connectivity of Spiny Lobster, Panulirus Interruptus, Across the California-Mexico International Border

Fisherman on boat

Marine organisms are often patchily distributed, consisting of local populations linked through dispersal. Lobster disperse during a 5-7 month larval phase after hatching, and because of the difficulties in tracking larvae while they drift in the currents from their source to their settlement site, the question of where larvae disperse, and consequently, the degree of connectivity, or interdependence among populations, remains largely unanswered.

There is a longstanding belief that lobster populations in the Southern California Bight are periodically replenished by the much larger populations in Baja, Mexico, when larvae drift northward in El Nino conditions. However, this hypothesis has never been tested directly. As part of a multi-species investigation that includes kelp bass, California sheephead and Kellet's whelk, this study aims to test the strength and scale of cross-border connectivity among populations between central Baja California, Mexico and Point Conception, California using DNA markers called microsatellites. By getting "DNA fingerprints" with microsatellite markers for lobsters in Baja and Southern California, we can determine how closely or distantly related individuals are and make inferences about the average scale and direction of dispersal.

The outcome of the genetic analysis of connectivity has profound implications for the management of fisheries for this species both in Mexico and California, with each scenario placing the source of recruits under the jurisdiction of markedly different management regimes.

Research Objectives


Kim Selkoe
Phone: (805) 259-7476
Email: selkoe@nceas.ucsb.edu

Project Timeline

Laboratory analysis is expected to conclude by late September 2007 with preliminary results expected by early November.


The applied nature of this work has resulted in direct collaborations with local fishermen and fishery participants as well as fishery managers and scientists in southern California and Baja, Mexico alike.

  • Jorge A. Rosales Casian, Centro de Investigacion Cientifica y de Educacion Superior de Ensenada
  • Eugenio Carpizo, Universidad Autonoma Baja California Ensenada
  • Arturo Ramirez Valdez, Universidad Autonoma Baja California Ensenada
  • Armando Vega Velazquez, Instituto Nacional de Pesca
  • Talib Wahab, Avicena Network, Inc.
  • Kristine Barsky, California Department of Fish and Game
  • Matthew Iacchei, Hawaii Institute of Marine Biology


This research is part of a large-scale effort aimed at understanding patterns of connectivity in nearshore marine species within the California Current Ecosystem, funded by the UC Coastal Environmental Quality Initiative.