History and context
Australia boasts a vast and varied coastline with an abundance and diversity of whale and dolphin species. Whale and dolphin watching is popular in many different locations in Australia, including Port Phillip Bay (PPB), a semi-enclosed bay offshore from Melbourne. The bay hosts populations of three species of dolphins, common dolphins (Delphinus delphis), common bottlenose dolphins (Tursiops truncatus) and the recently proposed Australian bottlenose dolphin or burrunan dolphin (Tursiops australis sp. nov.)1. Dolphin watching and swim tours started as a commercial activity in PPB in the early 1990’s, and includes both boat-based and in-water interactions with dolphin groups, concentrated primarily in the southern end of the bay2. By 1999/2000, eight permitted operators were offering dolphin watching tours (5 swim/sightseeing, 3 sightseeing). In 2001 the Dolphin Research Institute analysed data on dolphin interactions. The result was to set a limit on the number of dolphin swim-tour permits (4) to be issued for Port Phillip Bay for the 2003/04 season. A specific dolphin swim-tour permit application was developed, based on the existing Parks Victoria tour operator licence application. In 2007-2008 three operators were licensed to conduct boat-based activities accommodating an estimated 12,000 tourists over a six- month season2. As of 2013, the dolphin swim tour industry in PPB was capped at 4 licensed operators catering to around 11,600 tourists per year. In 2017 the Victoria Department of Environment, Land, Water and Planning (DELWP) issued four permits which are still current.
Located in such close proximity to the city of Melbourne and its outlying residential areas, the bay also hosts large volumes of commercial vessel traffic and extensive use of private recreational boats, particularly during weekends and holiday periods. Realizing the potential negative impact of this volume of vessel traffic, studies were undertaken in PPB from 1998 onward to try and assess the potential impact of dolphin watching activities on the small resident population of bottlenose dolphins found there3,4. This catalysed a process of adaptive management that has continued over the past 20 years.