Brice Semmens
Associate Professor
Marine Biology Research Division

California Cooperative Oceanic Fisheries Investigations (CalCOFI)

Brice Semmens is an associate professor in the Marine Biology Research Division at Scripps Institution of Oceanography at UC San Diego. Dr. Semmens is also the Director of the California Cooperative Oceanic Fisheries Investigations (CalCOFI) program ( His Lab Web page is available at

Dr. Semmens’ research is equal parts computer time and fieldwork. In the lab he focuses on developing novel methods for analyzing ecological information. In the field he uses advanced sampling techniques to characterize the movements and behaviors of marine animals as a function of habitat and interactions among individuals. In both research arenas, Semmens is driven by questions that are fundamentally useful to resource managers tasked with biological conservation in the face of increasing anthropogenic impacts.

Dr. Semmens makes use of a broad suite of analytic tools, including multi-level models, time/space series analysis, state-space model formulations, and information theoretic approaches to model selection. He has worked with data from a number of different ecosystems, including coral reef fish, Pacific salmonids, coastal gray wolves, southern resident killer whales, and coastal groundfish. In all of these projects, his goal has been to bridge predictions about how the world works with observed patterns, and in so doing gain insight into the forces regulating marine populations and ecosystems.

In the field, Dr. Semmens uses advanced tracking technologies to characterize marine fish behavior. For instance, he leads Grouper Moon, a multi-institution conservation project aimed at describing the spatial, demographic, and numerical impact of spawning-site marine protected areas (MPAs) on endangered Nassau grouper in the Cayman Islands. This project involves monitoring space use through acoustic telemetry, characterizing demographic responses to conservation action based on model fitting and parameter estimation, and characterizing the spatial aspects of fishing pressure through mark-recapture analysis. This research project was explicitly designed to carry out a comprehensive assessment of the risks Nassau grouper face, and by implication the potential benefits provided by spawning site protections in the Cayman Islands and elsewhere.

In Southern California, Dr. Semmens is using similar tagging techniques to unveil the behaviors of near-shore marine fishes of conservation concern (e.g. giant sea bass) and of importance to the recreational fishing community (e.g. spotted sand bass, kelp bass, barred sand bass).

Prior to joining Scripps, Semmens was a National Research Council postdoctoral fellow at the Northwest Fisheries Science Center. He received his Masters of Environmental Science and Management at the Bren School, UC Santa Barbara, and his Ph.D. in zoology from the University of Washington.

Last updated May 2012