Joshua Smith

Whale-watching activities are known to induce behavioural changes that are compatible with anti-predatory responses. However anti-predatory responses can vary depending on the species, population and/or site-specific environmental features. This variability makes it challenging to evaluate whale-watching disturbance and multiple metrics should therefore be used for any impact study. In this study we used meta-analyses to assess the consistency of anti-predatory responses among several studies on whale-watching disturbance. Changes in swimming speed, activity budget, inter-breath intervals, and deviation and directness index were used as proxies to measure whale-watching disturbance. We also assessed if these changes were due to extrinsic factors (the presence of whale watching regulations), intrinsic factors (species and animal body size) or environmental factors (habitat type). Our results showed that changes in the activity budget and directness and deviation index were the most consistently reliable metrics in capturing cetacean responses to whale-watching disturbance. Animals were more likely to travel and less likely to rest and forage (Q7=81.2, p< 0.0001, k=8; Q5=23.2, p=0.0003, k= 7; Q7=49.5, p< 0.0001, k=8) as a consequence of whale-watching presence. Body size also had an effect on resting activity with smaller animals being less likely to rest in the presence of boats (Q1=4.1, p=0.04, k=7). Our results showed a generalized tendency of cetaceans to increase their path sinuosity (deviation index) and decrease path linearity (directness index) in response to whale-watching disturbance (Q= 24.6, p= < 0.0001, τ2=0.09, k=5; Q= 8.94; p= 0.03, τ2=0.05, k=5). Path linearity and predictability also increased in corridor type habitats (SMD=1.55; p=0.004, k=5). We found that cetaceans overall showed similar anti-predatory responses to whale-watching activities. These behavioural changes reflect greater direct energy expenditure and fewer opportunities for energy recovery respectively and may cause long-term consequences to population fitness. We conclude with highlighting the validity of a meta-analytical approach in studying anthropogenic disturbances.

The Murdoch University Cetacean Research Unit is conducting research into marine mammal biology and ecology within a number of broad programs across Australia's north-western bioregion. These programs include assessing: population dynamics and behaviour (abundance estimation, social structure, genetic structure and population connectivity); anthropogenic impacts (fisheries bycatch, tourism and coastal development); ecosystem interactions (foraging ecology, trophic interactions, habitat modelling, protected areas); marine mammal health (e.g. pathology, eco-toxicology, parasitology); and, new approaches to research (remote methods for abundance estimation, statistical modelling, and citizen science). The Australian Marine Mammal Centre, Chevron, the Fisheries Research and Development Corporation and WAMSI II have funded this research. MUCRU's programs are being applied to numerous taxa at specific locations from the Gascoyne to the eastern Kimberley coast. In the Gascoyne, long-term behavioural, genetic and acoustic research on Indo-Pacific bottlenose dolphins is ongoing in Shark Bay. The use of Unmanned Aerial Vehicles to conduct surveys of marine megafauna (including dugongs and humpback whales) is also occurring in Shark Bay and, potentially, further north. This year, a dedicated program will commence on Indo-Pacific humpback dolphins around the North West Cape. Aerial surveys of dugongs are being conducted from Exmouth Gulf to Barrow Island and dugongs are being satellite tagged off Onslow. Research into population dynamics and the impact of commercial fishing on common bottlenose dolphins is being carried out off the Pilbara coast, while ongoing work on the genetic connectivity of bottlenose, humpback and snubfin dolphins takes place in the Pilbara's nearshore habitats. Across the Kimberley coast, we are studying little known populations of snubfin, humpback, bottlenose and spinner dolphins, using standardised sampling regimes, such as boat-based transects, photographic identification and biopsy sampling. This will provide the first robust estimates of abundance of snubfin and humpback dolphins anywhere in Western Australia. Our research on these species will diversify this year with the introduction of passive acoustic monitoring techniques. We are working with a number of internationally renowned adjuncts associated with, for example, Duke University, University of Zurich, Aarhus University, University of Southern Denmark and North Carolina State University. Australian and Western Australian collaborating institutions include James Cook University, University of New South Wales, Australian National University, Flinders University and Curtin University.

The wintering areas for humpback whales within the Great Barrier Reef World Heritage Area (GBRWHA) have been poorly defined, mainly because of the large size of the area which prohibits broad-scale surveys. This information gap was addressed by applying predictive spatial habitat modelling using presence-only sighting data from an opportunistic sightings database. The model identified high habitat suitability for breeding humpback whales in the southern GBRWHA, which decreased as latitude decreased. However, predictive habitat modelling is seldom validated and the accuracy of models is often unchecked. We recently validated this predictive model by conducting a dedicated line transect aerial survey that subsampled three regions in the GBRWHA predicted to represent areas of low, medium and high habitat suitability. The distribution and relative abundance of whales was investigated in relation to environmental variables using GIS and generalized additive models (GAMs). Data from the dedicated survey supports the predictive habitat model, with areas of high density closely reflecting areas of high habitat suitability identified by the predictive model. Encounter rates from the aerial survey were highest (0.04 per sq. km) in the southern GBRWHA and lowest (0.002 per sq. km) in the northern GBRWHA, according to un-modelled data. Calving areas were not separate from mating areas, and groups containing calves were distributed throughout the entire GBRWHA within the same range of groups sighted without calves. The area of highest density of whales on the breeding grounds corresponded to an offshore area adjacent to two coastal cities undergoing major port expansions, and within the GBRWHA inner shipping route. There are many proposed and several approved port expansions along the coastline adjoining the GBRWHA. With an associated increase in shipping activity and a rapidly recovering population of whales, ship strikes with breeding humpback whales are likely to be an emerging issue in Australia.