My research interests focus on the development of diving behavior in northern elephant seals. For my dissertation, I am investigating time-depth records and satellite tracks from known age breeding females in order to identify diving behaviors that change with time and allow older females to gain more weight and ultimately deliver more energy to their pups than younger females. I will also compare how blood oxygen stores relate to differences that emerge from dive analyses by quantifying the oxygen content of myoglobin and hemoglobin in addition to the plasma volume of each individual.

My master's thesis examined how northern elephant seals manage swimming speed as a critical variable to reduce drag and conserve oxygen while diving. I compared foraging strategies using swimming speed data between juveniles and adult females and males. Other projects that I have been involved with include the Laikipia Predator Project, where we investigated the movement patterns of lions and hyenas over unprotected ranching areas in northern Kenya . I have also worked extensively with the Santa Cruz Predatory Bird Research Project to monitor the breeding success of wild peregrines and supplement the population with captive-release efforts along the central California coast.

Hassrick, J.L., Crocker, D.E., Zeno, R.L., Blackwell, S.B., Costa, D.P., and Le Boeuf, B.J. (2005). Swimming speed and dive function of northern elephant seals, Mirounga angustirostris . 2 nd International Bio-logging Science Symposium.

Hassrick, J.L., Crocker, D.E., Zeno, R.L., Blackwell, S.B., Costa, D.P., and Le Boeuf, B.J. (2005). Swimming speed and foraging strategies of northern elephant seals, Mirounga angustirostris . Society for Integrative and Comparative Biology.

Hassrick, J.L., Crocker, D.E., Zeno, R.L., Blackwell, S.B., Costa, D.P., and Le Boeuf, B.J. (2004). Swimming speed and foraging strategies of northern elephant seals, Mirounga angustirostris . Master of Science Thesis (Advisor: Daniel E. Crocker) Sonomal State University.

Hassrick, J.L., Crocker, D.E., Zeno, R.L., Blackwell, S.B., Champagne , C.D., and Costa, D.P. (2003). Developmental changes in the foraging behavior of juvenile northern elephant seals. 15 th Biennial Conference on the Biology of Marine Mammals.