The Life-History and Behavior Group is one of the two groups under the Biology Program is designed to increase the available knowledge of the life-history and behavior of tunas, tuna like-species, and other associated species in the EPO. The other group under the program is the Early Life-History Group.

The Life-History and Behavior Group is responsible for the following major areas of activity:

1. Investigations of the biology and behavior of tunas, and deriving population parameter estimates.
2. Tuna tagging experiments to obtain vital information on movements and population structure, along with growth, mortality, and exploitation rates.
    

 

• Stock assessment
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• Ecosystem & Bycatch
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• Biology
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  • Early-life History
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  • Life-History & Behavior
     
  • Achotines Lab., Panama
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• Data Collection & Database
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E.1.a	Evaluate potential improvement of growth model for bigeye in the EPO based on presumed annuli counts from otoliths of large fish	Completed	Nov 2017-Nov 2019
E.2.a	Investigate spatiotemporal variability in the age, growth, maturity, and fecundity of yellowfin tuna in the EPO		Jun 2017-May 2022
E.2.b	Workshop to evaluate differences in bigeye tuna age estimation methods and resulting growth models utilized in current stock assessments by the IATTC and WCPFC	Completed	Jan 2019-Jan 2019
E.3.a	Investigate geographic variation in the movements, behavior, and habitat utilization of yellowfin tuna in the EPO		Jan 2020-Dec 2021
E.4.a	Multi-year tuna tagging study		Jan 2019-Dec 2023
E.5.a	Evaluate the Pacific-wide population structure of bigeye and skipjack tunas, using genetic analyses		Jan 2017-Dec 2020
E.5.b	Investigate the spawning ecology of captive yellowfin tuna, using genetic analyses	Completed	Jun 2018-Jun 2019
F.2.a	Investigate the movements, behavior, and habitat utilization of silky sharks in the EPO		Jan 2020-Dec 2021
M.2.a	Evaluate the post-release survival of silky sharks captured by longline fishing vessels in the equatorial EPO, using best handling practices	Completed	Jan 2016-Dec 2018
M.2.b	Evaluate best handling practices for maximizing post-release survival of silky sharks in longline fisheries, and identification of silky shark pupping areas for bycatch mitigation		Jan 2018-Dec 2020

• Buchalla, Y., D. Margulies, V. Scholey, S. Cusatti, and M.S. Stein. 2025. Food selectivity, diel feeding, and effect of light intensity on prey consumption, growth and survival of yellowfin tuna Thunnus albacares larvae. Marine Ecology Progress Series 10.3354/meps14799
• Schaefer, K. M. , and D. W. Fuller 2022. Spatiotemporal variability in the reproductive biology of yellowfin tuna (Thunnus albacares) in the eastern Pacific Ocean. Fisheries Research 10.1016/j.fishres.2022.106225
• Kurt M. Schaefer, Daniel Fuller 2021. Horizontal movements, utilization distributions, and mixing rates of yellowfin tuna (Thunnus albacares) tagged and released with archival tags in six discrete areas of the eastern and central Pacific Ocean. Fisheries OCeanography 10.1111/fog.12564
• Schaefer, K.M., Fuller, D.W. and Chaloupka, M. 2021. Performance evaluation of a shallow prototype versus a standard depth traditional design drifting fish-aggregating device in the equatorial eastern Pacific tuna purse-seine fishery. Fisheries Research 10.1016/j.fishres.2020.105763
• Kurt Schaefer, Daniel Fuller, José Leonardo Castillo-Geniz, Carlos Javier Godinez-Padilla, Michel Dreyfus, Alexandre Aires-da-Silva 2021. Post-release survival of silky sharks (Carcharhinus falciformis) following capture by Mexican flag longline fishing vessels in the northeastern Pacific Ocean. Fisheries Research 10.1016/j.fishres.2020.105779
• Schaefer, K.M. and Fuller, D.W. 2019. Spatiotemporal variability in the reproductive dynamics of Skipjack Tuna (Katsuwonus pelamis) in the eastern Pacific Ocean. Fisheries Research 10.1016/j.fishres.2018.09.002
• Schaefer, K.M., Fuller, D.W., Aires-da-Silva, A., Carvajal, J.M., Martinez, J. and Hutchinson, M.R. 2019. Postrelease survival of silky sharks (Carcharhinus falciformis) following capture by longline fishing vessels in the equatorial eastern Pacific Ocean. Bulletin of Marine Science 10.5343/bms.2018.0052
• Maunder, M.N., Deriso, R.B., Schaefer, K.M., Fuller, D.W., Aires-da-Silva, A.M., Minte‑Vera, C.V., Campana, S.E. 2018. The growth cessation model: a growth model for species showing a near cessation in growth with application to bigeye tuna (Thunnus obesus). Marine Biology 10.1007/s00227-018-3336-9
• Minte-Vera, C.V., Maunder, M.N., Schaefer, K.M. Aires-da-Silva, A. M. 2018. The influence of metrics for spawning output on stock assessment results and evaluation of reference points: An illustration with yellowfin tuna in the eastern Pacific Ocean. Fisheries Research 10.1016/j.fishres.2018.09.022
• Harrison, A.L., Costa, D.P., Winship, A.J., Benson, S.R., Bograd, S.J., Antolos, M., Carlisle, A.B., Dewar, H., Dutton, P.H., Jorgensen, S.J., Kohin, S., Mate, B.R., Robinson, P.W., Schaefer, K.M., Shaffer, S.A., Shillinger, G.L., Simmons, S.E., Weng, K.C., Gjerde, K.M., Block, B.A. 2018. The political biogeography of migratory marine predators. Nature Ecology & Evolution 10.1038/s41559-018-0646-8