Abstract
ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 34:61-73 (2017) - DOI: https://doi.org/10.3354/esr00839 Local abundance, apparent survival and site fidelity of Bryde’s whales in the Hauraki Gulf (New Zealand) inferred from long-term photo-identification G. Tezanos-Pinto1,*, K. Hupman1, N. Wiseman2, S. L. Dwyer1, C. S. Baker2,3, L. Brooks4, B. Outhwaite1, C. Lea1, K. A. Stockin1 1Coastal-Marine Research Group, Institute of Natural and Mathematical Sciences, Massey University, Private Bag 102904, North Shore, Auckland 0745, New Zealand 2The University of Auckland, Private Bag 92019, Auckland 1010, New Zealand 3Hatfield Marine Science Center, Oregon State University, 2030 SE Marine Science Drive, Newport, OR 97365, USA 4Marine Ecology Research Centre, Southern Cross University, PO Box 157 Lismore, New South Wales 2480, Australia *Corresponding author: gaby@pachamama.co.nz ABSTRACT: Bryde’s whales Balaenoptera edeni in New Zealand are classified as ‘nationally critical’ according to the New Zealand Threat Classification System. In the Hauraki Gulf, Bryde’s whales occur year-round and are subject to ship-strike mortality events. Photo-identification surveys were conducted to estimate local abundance, apparent survival and site fidelity during 2 periods from 2004 to 2006 (261 daily surveys) and from 2011 to 2013 (382 daily surveys). The photo-identification database contained a total of 364 sighting records of 72 Bryde’s whales. Overall, 20 whales were sighted across the 2 survey periods, indicating long-term site fidelity. Local abundance was estimated using the robust design (RD) and POPAN mark-recapture approaches for each period, including upward adjustment for the proportion of unmarked whales. RD seasonal abundance estimates varied from 17 to 43 whales between 2004 and 2006, and from 13 to 31 whales between 2011 and 2013. Temporary emigration followed a random pattern (γ’ = γ’’) and was estimated at 0.557 between 2004 and 2006, and 0.610 between 2011 and 2013. POPAN seasonal abundance ranged from 38 to 74 whales for the 2004 to 2006 period and from 42 to 68 whales for 2011 to 2013. Apparent survival was estimated across periods at 0.878 (95% CI = 0.811-0.923). From the ‘super population’ estimate of the 2011 to 2013 survey period (Nsuper = 135 whales, CI = 100-183), we calculated a potential biological removal (PBR) of 1 whale yr-1. Given the impact of ship strikes on this local unit, it is important to continue long-term photo-identification of Bryde’s whales. This technique provides valuable demographic information for a poorly known species. KEY WORDS: Mark-recapture · Pollock robust design · POPAN · Residency · Balaenoptera · ∙ Cetacean Full text in pdf format Supplementary material PreviousNextCite this article as: Tezanos-Pinto G, Hupman K, Wiseman N, Dwyer SL and others (2017) Local abundance, apparent survival and site fidelity of Bryde’s whales in the Hauraki Gulf (New Zealand) inferred from long-term photo-identification. Endang Species Res 34:61-73. https://doi.org/10.3354/esr00839 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 34. Online publication date: July 21, 2017 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2017 Inter-Research.
Highlights
Bryde’s whales Balaenoptera edeni are the least known of the large whales (Kato 2002) and are distributed worldwide in tropical and temperate waters, usually between latitudes 40° N and 40° S
Any marine mammal population with an estimate of human-induced mortality that is greater than its potential biological removal (PBR) has a level of mortality that could lead
Our results provide the first analysis of longterm site fidelity and estimates of apparent survival for Bryde’s whales in the Hauraki Gulf using photoidentification methods
Summary
Bryde’s whales Balaenoptera edeni are the least known of the large whales (Kato 2002) and are distributed worldwide in tropical and temperate waters, usually between latitudes 40° N and 40° S. New Zealand Bryde’s whales have been identified as B. edeni brydei, the so-called ‘offshore form’ (Wiseman 2008). In New Zealand, Bryde’s whales are reported only for the north-eastern coast of the North Island (Baker & Madon 2007, Wiseman 2008) and occur year-round in the Hauraki Gulf (Behrens & Constantine 2008, Wiseman et al 2011). The whales have been observed throughout the inner Gulf in water depths ranging from 12 to 60 m (Wiseman et al 2011). Some whales have been resighted regularly over multiple years, including reproductive females accompanied by their calves (Wiseman 2008)
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