We document the occurrence of mothers and calves in the PCFG area over a more than 20-year period. Over the course of the study 62 moms were documented with 102 calves with a high proportion of these seen in recent years (11 to 18 per year in each of the last four years, 2012-15). This appeared to be a combination of higher number of calves in recent years and greater focus on accurately documenting mothers with calves in more recent years. Overall 59 of 91 (65%) calves documented through 2014 were resighted in a year subsequent to their birth year and indicates a higher degree of internal recruitment to the PCFG than had been suggested by previous less complete data. Average weaning date appeared to be around 1 August, a date earlier than the initial encounters with some whales and indicates how especially in past years with more limited effort, the number of calves would have been underestimated.
Calambokidis, J., and A. Perez. 2017. Sightings and follow-up of mothers and calves in the PCFG and implications for internal recruitment. IWC Report SC/A17/GW/04 for the Workshop on the Status of North Pacific Gray Whales. 27-29 April 2017. La Jolla, CA. 8pp.Download PDF
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