Dusky dolphin (Lagenorhynchus obscurus) behavior and human interactions: implications for tourism and aquaculture
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Interactions between humans and dusky dolphins in the coastal waters of New Zealand are increasing. My research focused on tourism interactions, with Kaikoura as the study site; and, on habitat use in an active aquaculture area, with Admiralty Bay as the study site. In Kaikoura, companies engaged in commercial cetacean tourism (For Hire Company) have permits issued by the New Zealand’s Department of Conservation, allowing them to take paying customers out to view and swim with wild dusky dolphins. During summer and fall of 2005, I assessed the effectiveness of a voluntary ‘rest period’ established to give time free of humans to the dolphins. I used a theodolite to track the movements of large groups of dusky dolphins and recorded the arrival, departure and behaviors of all vessels approaching within 400 m of the group. The ‘rest period’ resulted in a reduction of vessel visits compared to non-rest periods, yet one For Hire Company and private recreational vessels continued to visit dusky dolphin groups during this time. To increase compliance with the voluntary regulation, more education is needed targeting private recreational vessels. Weekend traffic was higher compared to weekday traffic, during both rest and non-rest periods; a large increase occurred in weekend non-commercial vessel traffic. Swimming with calves is prohibited by New Zealand’s Marine Mammal Protection Regulations of 1992, yet 71.4 percent of the swim attempts I observed on-board For Hire Company tours were conducted with groups containing calves. More should be done to reduce the number of swims conducted with groups of dusky dolphins containing calves. In winter of 2005, I used hourly theodolite scans to record the number of dusky dolphin groups using Admiralty Bay, a different near-shore environment with less tourism than off Kaikoura, and with near-shore mussel farms. Groups of dusky dolphins were observed in Admiralty Bay using the full extent of the bay. This re-enforces previous findings that Admiralty Bay is an important winter foraging ground for dusky dolphins, and further aquaculture development in the bay would remove available foraging habitat.
Duprey, Nicholas Matthew Thomson (2007). Dusky dolphin (Lagenorhynchus obscurus) behavior and human interactions: implications for tourism and aquaculture. Master's thesis, Texas A&M University. Available electronically from