Dear Colleagues,
We are pleased to announce
publication of the
following article:
Chivers, S. J., W. L. Perryman, M. S.
Lynn, T.
Gerrodette, F. I. Archer, K. Danil, M. Berman-Kowalewski, and J.
P. Dines.
2015. Comparison of reproductive parameters for populations of
eastern North
Pacific common dolphins: Delphinus
capensis and D.
delphis. Marine
Mammal Science DOI: 10.1111/mms.12244.
Abstract
Reproductive
parameters were
estimated and compared for eastern North Pacific populations of
common dolphins
using specimen and photogrammetric data. Age and length data for
Delphinus
capensis and D. delphis specimens recovered as
bycatch or strandings
were used to estimate the postnatal growth rates needed to
estimate age for
calves measured in aerial photographs. Bayesian methods
propagated uncertainty
among models and revealed that the 2009 cohort of calves had
birth dates
centered on 6 March 2009 for D. capensis and 12 December
2008 for D.
delphis. The evidence for discrete calving seasons
suggests a mechanism of
reproductive isolation has evolved between species.
Photogrammetric data and
Bayesian methods were also used to estimate the average length
at which calves swim
independently: 145.1 cm (≈ 11.1 mo) in D. capensis and
140.1 cm (≈ 14.0 mo) in D. delphis, and the proportion
of calves
(calves/dolphins counted): 0.045 in D. capensis and
0.069 in D.
delphis. The latter parameter was converted to an index of
calf production
(calf/female dolphin) that was >50% lower than pregnancy
rates suggesting
few births occurred during the study year. Comparisons of
regional differences
in calf production suggest variability in habitat use patterns
within the study
area.
http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1748-7692/earlyview
You may
also contact me at susan.chivers@noaa.gov
for a pdf.
Cheers,
Susan
-- Susan J. Chivers, Ph.D. Marine Mammal and Turtle Division Southwest Fisheries Science Center National Marine Fisheries Service National Oceanic and Atmospheric Administration 8901 La Jolla Shores Dr. La Jolla, CA 92037 USA Phone: 858-546-7093 FAX: 858-546-7003 Email: Susan.Chivers@noaa.gov http://swfsc.noaa.gov/PRD-PhotoLH.aspx