Identified ThreatsIdentified Threats

Identified Threats

1. The resumption of commercial whaling and/or the expansion of scientific whaling

The impacts of commercial hunting on humpback whale populations have been well documented. While currently banned under the IWC moratorium on commercial whaling, the potential for commercial whaling to recommence exists and pressure may well increase as populations recover.

An additional area of concern is the potential expansion of de facto commercial whaling under the guise of scientific whaling. The IWC Convention allows member states to issue special permits to kill whales for research purposes and then process these animals for sale. Since 1986, Japan and Iceland have issued special permits for several whale species as part of their scientific whaling research programs. The recent expansion of these programs in the Northern Hemisphere involve the killing of various baleen whales including minke, Bryde's, fin, sperm and sei whales. In addition, since the implementation of the Southern Ocean Sanctuary in 1994, Japan has continued to harvest minke whales there under special permits. It is quite possible that humpback whales will be included in future research programs.

2. Habitat degradation

Humpback whales use habitat seasonally and can typically be found along various parts of the Australian coastline for up to nine months of the year (April to December). Anthropogenic activities have the potential to degrade habitat important to the species. These activities may degrade habitat by operating at times that coincide with the presence of whales, or they may occur when whales are absent, but degrade habitat suitability on a permanent or semi-permanent basis. These activities may include:

• acoustic pollution (e.g. commercial and recreational vessel noise, and seismic survey activity);
• entanglement (e.g. in marine debris, fishing and aquaculture equipment);
• physical injury and death from ship strike;
• built structures that impact upon habitat availability and/or use (e.g. marinas, wharves, aquaculture installations, mining or drilling infrastructure);
• changing water quality and pollution (e.g. runoff from land based agriculture, oil spills, outputs from aquaculture); and
• changes to water flow regimes causing extensive sedimentation or erosion or altered currents in near shore habitat (e.g. canals and dredging).

The species’ dependence on inshore areas means that individual animals may be subject to the impacts from any or all of these activities. Habitat degradation may result in reduced occupancy and/or exclusion of individual whales from suitable habitat, compromised reproductive success, and mortality. It is possible that impacts on a sufficient number of individual whales could lead to broader impacts at the population level, e.g. by reducing recruitment to such an extent that species recovery is impeded. This would be more likely to arise where activities that cause habitat degradation occurred intensively and/or cumulatively, or over a large portion of their range.