Dwarf minke whales in the northern Great Barrier Reef and implications for the sustainable management of the swim-with whales industry

• Main Author: Sobtzick, Susan
• Format: Thesis
• Language: unknown
• Published: 2010
• Subjects: Austral; Balaenoptera acutorostrata; minke whale
• Online Access: https://researchonline.jcu.edu.au/28199/1/28199-sobtzick-2010-thesis.pdf

The dwarf minke whale is an undescribed subspecies of the common minke whale (Balaenoptera acutorostrata). Dwarf minke whales aggregate in the northern Great Barrier Reef each austral winter. The predictability of the aggregations and the tendency of the whales to approach vessels and swimmers have led to the development of a swim-with whales industry which, since 2003, has been formally permitted by the Great Barrier Reef Marine Park Authority. Dwarf minke whale biology is not well understood and any impacts of the swim-with activities on the dwarf minke whale population are largely unknown and unquantified. In order to address these knowledge gaps, I designed my study with three overarching aims (1) to improve our understanding of dwarf minke whales involved in swim-with programs; (2) to assess the potential for cumulative impacts of the swim-with whales activities on the whales and (3) to make recommendations to contribute towards sustainable management of the activity (including the evaluation of potential sustainability indicators). I addressed these aims by using underwater photo-identification data of dwarf minke whales involved in swim-with activities. Between 2006-2008, over 45,000 photos and video footage were collected by myself, other Minke Whale Project researchers and non-scientists onboard platforms of opportunity forming the Dwarf Minke Whale Sightings Network. I evaluated the quality of the data and found it to be suitable for individual whale identification, with non-scientists contributing more than 40% of the high quality data. In 2006, I identified a minimum of 176 individuals (complete identifications that include both left and right sides of the individual plus the higher number of the partial identifications, either left or right side) and a maximum of 195 individuals (complete IDs and the sum of the partial IDs). In 2007, the minimum number of identified whales was 158 with a potential maximum of 171 individuals; in 2008, I identified a definite minimum of 204 and a potential maximum of ...