[MARMAM] New paper on the abundance of North Atlantic right whales

Peter Corkeron - NOAA Federal peter.corkeron at noaa.gov
Fri Sep 22 08:04:27 PDT 2017


Greetings Marmamers

On behalf of my coauthors, I am pleased to announce the publication of a
new paper on the abundance of North Atlantic right whales.

The paper's citation is:

Pace III RM, Corkeron PJ, Kraus SD. State–space mark–recapture estimates
reveal a recent decline in abundance of North Atlantic right whales. Ecol
Evol. 2017;00:1–12. https://doi.org/10.1002/ece3.3406

And the abstract is:

North Atlantic right whales (Eubalaena glacialis Müller 1776) present an
interesting problem for abundance and trend estimation in marine wildlife
conservation. They are long lived, individually identifiable, highly
mobile, and one of the rarest of cetaceans. Individuals are annually
resighted at different rates, primarily due to varying stay durations among
several principal habitats within a large geographic range. To date,
characterizations of abundance have been produced that use simple
accounting procedures with differing assumptions about mortality. To better
characterize changing abundance of North Atlantic right whales between 1990
and 2015, we adapted a state–space formulation with Jolly-Seber assumptions
about population entry (birth and immigration) to individual resighting
histories and fit it using empirical Bayes methodology. This hierarchical
model included accommodation for the effect of the substantial individual
capture heterogeneity. Estimates from this approach were only slightly
higher than published accounting procedures, except for the most recent
years (when recapture rates had declined substantially). North Atlantic
right whales' abundance increased at about 2.8% per annum from median point
estimates of 270 individuals in 1990 to 483 in 2010, and then declined to
2015, when the final estimate was 458 individuals (95% credible intervals
444–471). The probability that the population's trajectory post-2010 was a
decline was estimated at 99.99%. Of special concern was the finding that
reduced survival rates of adult females relative to adult males have
produced diverging abundance trends between sexes. Despite constraints in
recent years, both biological (whales' distribution changing) and
logistical (fewer resources available to collect individual
photo-identifications), it is still possible to detect this relatively
recent, small change in the population's trajectory. This is thanks to the
massive dataset of individual North Atlantic right whale identifications
accrued over the past three decades. Photo-identification data provide
biological information that allows more informed inference on the status of
this species.

Ecology and Evolution is an Open Access journal, so the paper is freely
available at:
http://onlinelibrary.wiley.com/doi/10.1002/ece3.3406/abstract

If you’d like the paper, please download it from the journal’s site.

If the journal's site download isn't an option for you, the paper is also
available via Researchgate at:
https://www.researchgate.net/publication/319904432_State-
space_mark-recapture_estimates_reveal_a_recent_
decline_in_abundance_of_North_Atlantic_right_whales

I hope this is of interest.
Peter

-- 

Leader, Large Whale Team
Protected Species Branch
NOAA Northeast Fisheries Science Center
166 Water St
Woods Hole MA 02543

phone: 508-495-2191
webpage: https://www.nefsc.noaa.gov/psb/psbStaff_PeterCorkeron.html
ResearchGate: researchgate.net/profile/Peter_Corkeron
Orcid: orcid.org/0000-0003-1553-125
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