Identified ThreatsIdentified Threats

Identified Threats

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

The impacts of commercial hunting on blue, fin and sei whales 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. While not likely in the near future for blue whales, there is no guarantee that blue, fin or sei whales will not be included in future research programs.

2. Habitat degradation

A range of anthropogenic activities have the potential to degrade habitat important to the survival of blue, fin and sei whales. 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).

Of the three species covered by this plan, blue whales are potentially the most likely to be affected by these processes because of the species’ use of Australian coastal waters. Given the limited knowledge about the use of habitat by fin and sei whales, it is difficult to determine the extent of the threat of habitat degradation to these species.

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.