No abstract

This study assessed the short‐term responses of humpback whales to whale‐watching vessels during their southward migration along the south coast of New South Wales (NSW), Australia. The behavior of pods was recorded from commercial whale‐watching vessels during tours and compared to pods observed in the absence of vessels from the shore in the same area. While some individuals showed obvious signs of horizontal avoidance, others approached vessels, initiating interactions. Calf pods were more sensitive to the presence of vessels than non‐calf pods. Dive times and the overall percentage of time whales spent submerged were higher in the presence of vessels, but respiration intervals did not differ. Some surface behaviors occurred less often in the presence of vessels. Whales' responses differed according to whether vessels were operating in accordance with regulations or not. Whales were more likely to avoid a vessel moving within the permitted 100 m approach limit than vessels outside the limit. Whales showed some behavioral changes when vessels operated in accordance with whale‐watching regulations, compared with whales in the absence of vessels. Pods that showed no obvious horizontal responses to vessels changed their diving and surface activity when compared with pods in the absence of vessels. Because the long‐term impacts of effects of vessels are unknown, management of the humpback whale‐watching industry should adopt a conservative approach. Improved knowledge of long‐term impacts of multiple exposures to vessels is required to inform management of the effects of whale‐watching.

No abstract

Kangaroo–vehicle collisions are frequent on Australian highways. Despite high economic costs, detrimental effects on animal welfare, and potential impacts on population viability, little research has been done to investigate the impact of road mortality on kangaroo populations, where and why accidents occur, and how the collisions can be mitigated. We therefore collected data on species (Macropus rufus, M. giganteus, M. fuliginosus, M. robustus), sex and age of kangaroos killed on a 21.2-km bitumenised section of outback highway over 6 months in far western New South Wales, Australia. The spatial and temporal distribution of road-killed kangaroos was investigated in relation to the cover and quality of road-side vegetation, road characteristics, the density of kangaroos along the road, climatic variables and traffic volume. A total of 125 kangaroos were found killed on the road at a rate of 0.03 deaths km–1 day–1. Grey kangaroos of two species (M. giganteus, M. fuliginosus) were under-represented in the road-kill sample in comparison with their proportion in the source population estimated during the day. No bias towards either sex was found. The age structure of road-killed kangaroos was similar to age structures typical of source kangaroo populations. Road-kills mainly occurred in open plains country. In road sections with curves or stock races, road-kill frequencies were higher than expected. Greater cover and greenness of roadside vegetation at the verge probably attracted kangaroos to the road and variation in this vegetation affected the spatial distribution of road-kills. The temporal distribution of road-kills was positively correlated with the volume of night-time traffic. The probability of a kangaroo–vehicle collision increased exponentially with traffic volume. Results are discussed in relation to the potential for mitigation of kangaroo–vehicle collisions.