[MARMAM] New paper on abundance of endangered false killer whales in the main Hawaiian Islands

Amanda Bradford - NOAA Federal amanda.bradford at noaa.gov
Thu Sep 6 12:59:30 PDT 2018

Aloha MARMAM community -

On behalf of my coauthors, I would like to share our new paper on the
abundance of endangered false killer whales in the main Hawaiian Islands:

Bradford AL, Baird RW, Mahaffy SD, Gorgone AM, McSweeney DJ, Cullins T,
Webster DL, Zerbini AN. 2018. Abundance estimates for management of
endangered false killer whales in the main Hawaiian Islands. Endangered
Species Research 36:297-313, DOI: https://doi.org/10.3354/esr00903

The paper is open access and a PDF can be downloaded from the journal's
website: <https://www.int-res.com/abstracts/esr/v36/p297-313/>.

If you have not yet had your morning tea or coffee and are not quite ready
for a full discussion of mark-recapture abundance estimation and sampling
variability, you can have a look at the paper's abstract (pasted below) or
check out the NOAA Fisheries Feature Story on this collaborative effort: <

ABSTRACT: Effectively using the best available data to meet management
mandates for endangered populations is a common conservation challenge.
False killer whales *Pseudorca crassidens* occur as 3 distinct populations
in Hawaiian waters, including a resident main Hawaiian Islands (MHI)
population that is endangered under the US Endangered Species Act. A
longitudinal, photo-identification dataset of 171 distinctive individuals
and open mark-recapture methods were used to estimate current MHI false
killer whale abundance as needed for management of this population. The
data are from dedicated and opportunistic surveys conducted from 2000 to
2015 around the MHI and reflect unquantified spatiotemporal biases imposed
by necessary sampling constraints. Accounting for temporal variation and
especially social group affiliation was important in modeling capture
probability. Sensitivity analyses found that the resulting time series of
16 abundance estimates is robust to some forms of sampling variability and
bias. However, because the study area was partially sampled each year, the
annual abundance estimates apply only to the portion of the population
using the sampled area and may underestimate true population abundance.
Nonetheless, the resulting estimates and supporting evidence indicate that
the MHI false killer whale population is relatively small; for example,
only 167 (SE = 23, 95% CI = 128-218) individuals were estimated to have
used the sampled area in 2015. Until data are available to estimate or
overcome sampling biases, this estimation framework offers a tool for using
data that have been regularly collected each year to produce current
abundance estimates that are improvements over existing management inputs.

Let me know if you have any questions about the paper or any difficulties
with the links or PDF.

Kind regards,


[image: Follow-Us-HICEAS-emblem.png]

*Amanda L. Bradford, Ph.D.*
Research Ecologist, Cetacean Research Program
Pacific Islands Fisheries Science Center, NOAA Fisheries
(808) 725-5714

Mailing address:
NMFS/PIFSC/PSD/Amanda Bradford
1845 Wasp Blvd., Building 176
Honolulu, HI 96818
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