Pelayo González, L., P., Tercero Dander, M.d.C., Gutiérrez Osuna, L.M., Burciaga & C., Hernández Camacho (2022). Potential California sea lion (Zalophus californianus) parturitions after the pupping season. 24th Biennial Conference on the Biology of Marine Mammals. Florida, Estados Unidos de América, agosto 1 - 5, 2022, 490-491.
Lili Pelayo González 1, Paula Tercero Dander 1, María del Carmen Gutiérrez Osuna 2, Luis Miguel Burciaga 3 y Claudia Hernández Camacho 1
The reproductive cycle of the California sea lionis highly synchronized and annual. This speciesbreeds in the North Pacific Ocean from theFarallon Islands in the United States to SantaMargarita Island in Mexico, including colonies inthe Gulf of California. We present data thatsuggest that some California sea lion pups wereborn after the pupping season in colonies locatedin Mexico. In June and July of 2010, we capturedand tagged pups to estimate their growth ratesduring their first year of life on Santa MargaritaIsland. We returned to the colony in November2010 and February 2011 to capture and weigh thetagged pups, as well as additional untagged pups.Among the newly captured pups, we found pupsof similar weight and size to pups captured inJuly 2010 (pupping season). When we appliedthe estimated growth rates for the U.S. coloniesin retrospect (with favorable and anomalousenvironmental conditions such as El Niño), wedetermined that the pups captured in November2010 must have been born between August andSeptember of the same year, while the pupscaptured in February 2011 must have been bornbetween October and November 2010. Anotheropportunistic observation was obtained inNovember 2019, when we sighted an apparentlypregnant adult female at the Los Islotes colony.This is the first report on births after the puppingseason in any pinniped. Our results suggest thatunder unfavorable environmental conditions(e.g., El Niño events 2009–10, 2019–20), somefemales show certain plasticity in the duration ofthe embryonic diapause, delaying the start ofgestation. Our results are preliminary, and morestudies are needed to determine whether thisspecies’ reproductive cycle is less synchronizedthan previously thought.
Palabras clave: Fecundidad; Ciclo reproductivo; Pinnípedos; Golfo de California
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