TITLE:
Utilizing Occupancy Models and Platforms-of-Opportunity to Assess Area Use of Mother-Calf Humpback Whales
AUTHORS:
J. J. Currie, S. H. Stack, J. A. McCordic, J. Roberts
KEYWORDS:
Humpback Whale, Occupancy Model, Platform of Opportunity, Whale and Dolphin Tracker, Area Use
JOURNAL NAME:
Open Journal of Marine Science,
Vol.8 No.2,
April
18,
2018
ABSTRACT:
The Hawaiian Islands, and particularly the Maui 4-island region, are a critical
breeding and calving habitat for humpback whales (Megaptera novaeangliae)
belonging to the Hawaii distinct population segment. Our aims were to test
the use of platforms-of-opportunity to determine trends in mother-calf pod
use of the region and to present opportunistic platforms as an alternative method
of long-term, cross-seasonal monitoring. Data were collected from whale
watching vessels over a 4-year period and analyzed using occupancy models to
determine the probability of habitat use of pods with calves and pods without
calves within the study area. Detection probability was influenced by survey
effort and month for all pod types with detection of adult only pods further
influenced by year. Pods with a calf showed a preference for shallow (75 meters). Results presented here align with previous work,
both in Hawaii and in other breeding grounds, which show a distinct segregation
of mothers with a calf from other age-classes of humpback whales. The
need for long-term continuous monitoring of cetacean populations is crucial
to ensure species conservation. Data collected aboard platforms-of-opportunity,
as presented here, provide important insight on humpback whale spatial and
temporal distribution, which are essential for species protection and management.