Using Cost-Effective Surveys From Platforms of Opportunity to Assess Cetacean Occurrence Patterns for Marine Park Management in the Heart of the Coral Triangle
Sahri, Achmad ; Mustika, Putu Liza Kusuma ; Purwanto, Purwanto ; Murk, Albertinka J. ; Scheidat, Meike - \ 2020
Frontiers in Marine Science 7 (2020). - ISSN 2296-7745
cetacean - Coral Triangle - marine park management - platforms of opportunity - spatio-temporal occurrence
For Marine Protected Areas (MPAs) to be effective in conservation their zoning and management needs to be based on scientific data. Obtaining information on spatio-temporal occurrence patterns of cetaceans can be especially challenging. This study used platforms of opportunity (i.e., fishing monitoring vessels) from May 2004 to May 2012 as a cost-effective way to address this knowledge gap in the Wakatobi National Park (WNP) at the heart of Coral Triangle, an important area for cetaceans in Indonesia. A database was created of cetacean sightings per surveyed days at sea, allowing for an analysis of species diversity and habitat use around the islands. Of the 11 cetacean species identified, spinner and bottlenose dolphins were sighted most often, followed by melon-headed and sperm whales. Spinner dolphin showed a wide distribution in the area, whilst bottlenose dolphin and melon-headed whale occupied the waters between the main islands and south atolls. Sperm whales occurred mostly in waters north of the main islands and as melon-headed whales, mostly in deep waters. Most cetacean sightings occurred in the zones designated for human use, indicating where potential conflicts might occur. No sightings were found in the Park core zone, suggesting a mismatch between WNP design and the cetacean ecological needs. Based on a sub-sample of the dedicated fishing monitoring sightings a sighting frequency was derived. Small and large cetaceans were reported mostly during inter-monsoonal seasons, possibly related to increased prey availability due to seasonal upwelling and increased survey activity. Inter-annual occurrence of cetaceans was variable, with no large cetaceans being sighted in 2010–2012, likely due to reduced survey efforts. In areas with limited resources for designated surveys, the use of platforms of opportunity can be a cost-effective tool to provide valuable data on cetacean occurrence. While data collection protocols in the WNP can be improved further, the results presented here already help identify potentially important areas as well as highlight where to direct designated research efforts. We advise to protect currently unprotected cetacean important habitats, and strictly regulate human activities in the current use zones for future WNP rezoning processes.
A treasure from the past : Former sperm whale distribution in Indonesian waters unveiled using distribution models and historical whaling data
Sahri, Achmad ; Putra, Mochamad I.H. ; Mustika, Putu L.K. ; Murk, Albertinka J. - \ 2020
Journal of Biogeography 47 (2020)10. - ISSN 0305-0270 - p. 2102 - 2116.
cetacean - conservation management - generalized additive model - historical whaling data - Maxent - species distribution model - sperm whale
Aim: This study is the first in Indonesia to assess historical sperm whale (Physeter macrocephalus) seasonal distributions by combining historical whaling data with environmental factors associated with sperm whale habitat preferences. As current records of whale occurrence covering the whole of Indonesian waters are incomplete, we used historical whaling data summarized by Charles Haskins Townsend in 1935 to model its potential distribution for each season. Location: Indonesian waters (92-143E, 9N-14S). Taxa: Sperm whale (P. macrocephalus). Methods: We used a presence-only habitat model – Maximum Entropy (Maxent) –, and a presence–pseudo-absence method – generalized additive model (GAM) – with nine submerged topographic variables to predict historical seasonal distributions. Results: Both Maxent and GAM predict similar potential distribution which align closely with the whaling data. The results indicate that in four areas in the eastern part of Indonesia, no seasonal differences occurred in sperm whale distribution, while noticeable seasonal differences were indicated in other areas. The key parameters that characterize sperm whale habitat in both models were distance to coast, distance to −1,000 and −5,000 m isobaths, and submarine key features such as trough and trench. Main conclusions: The historical catch data of this species can be used to describe the historical species distribution and provide a baseline to assess present distribution, prioritize current research and monitoring and recommend future data collection. Our models also predict distributions that are significantly larger than the ones occupied by sperm whales nowadays, another example of a shifting baseline. Our study demonstrates the benefits of incorporating historical whaling data into habitat models for ecological investigation and to inform conservation efforts for cetaceans.
Aerial surveys of cetaceans and seabirds in Irish waters : occurrence, distribution and abundance in 2015-2017
Rogan, E. ; Breen, P. ; Mackey, Mick ; Cañadas, Ana ; Scheidat, M. ; Geelhoed, S.C.V. ; Jessopp, Mark - \ 2018
Department of Communications, Climate Action & Environment - 298 p.
observe programme - aerial survey - cetacean - seabird - abundance - density - megafauna - distance sampling - Ireland - Atlantic - Celtic Sea - Irish Sea