Olaf Jensen

he/him

Director, Cornell Biological Field Station; Associate Professor, Natural Resources and the Environment Section

About

Olaf Jensen is an Associate Professor in fisheries and aquatic sciences in the Section of Natural Resources and the Environment and the director of the Cornell Biological Field Station. Research in the Jensen lab spans a range from field studies of recreational fisheries and climate change in the U.S. and Mongolia to impacts of oil spills and marsh restoration in the northern Gulf of Mexico. Our research on global fisheries sustainability has used stock assessment data to examine the relative effectiveness of different management approaches, the recovery time of overfished populations, the effectiveness of marine reserves, and the impacts of climate change on marine fish and invertebrates. We study fisheries as social-ecological systems, including fish (of course!) as well as the people who harvest them.

Education

University of Wisconsin-Madison, Limnology, Ph.D., 2008
University of Maryland, Marine Science, MS, 2004
Cornell University, Biology & Society, BA, 1998

Recent Research

Research in the Jensen lab is centered broadly on the goal of enhancing fisheries sustainability in an era of unprecedented environmental change. Specific research topics include: Climate change ecology - Can we predict how environmental change in lakes, rivers, and the ocean will impact fish growth, reproduction, and population change? What are the critical factors that most limit the resilience of fish populations to environmental change? Fish population dynamics - How do fish populations change in response to fishing and changes in the environment? How do we manage the vast majority of fisheries for which little scientific monitoring takes place? Fishery management - What are the characteristics of sustainable fishery management systems and how do these characteristics differ depending on the social and environmental context? Dynamics of fisheries systems - How do fish populations change in response to fishing and in turn how do fishers perceive and respond to changing fish populations?

Courses Taught

NTRES 3110 (Lec) and 3111 (Lab): Fish Ecology, Conservation and Management

Contact Information

Fernow, 211A

Ithaca, NY 14853

opj1 [at] cornell.edu

Publications
Pélissié, M., Devictor, V. Jensen, O.P., and V. Dakos. 2006. Abrupt declines in fish productivity often precede stock collapses in marine fisheries. Science Advances
12, eaed7911
https://www.science.org/doi/10.1126/sciadv.aed7911

Brooks, G., Frater, P.N., Jensen, O.P., Hansen, G.J.A., Paukert, C., Verhoeven, M., Wszola, L., Xu, L., Feiner, Z.S. 2026. Mixed Support for the Temperature-Size Rule in Wild Freshwater Fishes. Ecology Letters29, no. 2:e70344.

Xu, L., Embke, H.S., Free, C.M., Hansen, G.J.A., Lynch, A.J., Paukert, C.P., Sievert, N.A., and Jensen, O.P. 2025. Disentangling the historical impacts of warming and fishing on exploited freshwater fish populations. Science Advances 11, eadx5138
https://www.science.org/doi/10.1126/sciadv.adx5138

Solokas M.A., Feiner Z.S., Al‐Chokachy R., Budy P., DeWeber J.T., Sarvala J., Sass G.G., Tolentino S.A., Walsworth T.E., Jensen O.P. (2023) Shrinking body size and climate warming: Many freshwater salmonids do not follow the rule. Global Change Biology, 29(9): 2478-2492.

Melnychuk, M., et al. 2021. Identifying management actions that promote sustainable fisheries. Nature Sustainability. 4, 440-449.

Free, C.M., Thorson, J.T., Pinsky, M.L., Oken, K.L., Wiedenmann, J., Jensen, O.P. 2019. Impacts of historical warming on marine fisheries production. Science. 363: 979-983.

Neubauer, P., O.P. Jensen, J.A. Hutchings, and J.K. Baum. 2013. Resilience and recovery of overexploited marine populations. Science. 340:347-349.