Humans & marine mammals

The relationship between humans and Australia's marine mammals (about 46 species of whale and dolphin, 10 species of seals and the dugong) is culturally influential, diverse and has a high profile. Dugongs and stranded whales have been important spiritually and trophically to some Aborigines and Torres Strait Islanders for tens of thousands of years, and the early exploitation of baleen whales, elephant seals and fur seals was the commercial driver of much of the earliest European settlement.

Today, Australia's marine mammal protection laws are among the most stringent in the world and Australia is a leading voice on international marine mammal conservation issues, particularly in the International Whaling Commission. The Australian public and media are more strongly engaged in environmental issues concerning marine mammals than almost any other country and have a clear expectation that human activities will not unduly interfere with these taxa. The Environment Protection and Biodiversity Conservation Act 1999 is the major piece of legislation that manages these interactions and, like State legislations, it relies upon a sound scientific basis to ensure adequate marine mammal protection, along with appropriate opportunities for the development of sustainable marine industries and recreational practices.

Our interactions with marine mammals are diverse and increasing. They may have neutral, positive or negative outcomes and these may operate at scales from an individual animal to a population, from short term to chronic and from sub-lethal to lethal. Interactions may lead to direct effects (e.g. death, injury or displacement) or indirect effects (habitat damage or competition for food). Multiple interactions may lead to cumulative effects, and most of these are very difficult to measure. Emerging issues such as the potential effects of climate change or effects of contaminants on mammal health remain to be elucidated. Our understanding of the nature and extent of interactions is generally naïve, making their management difficult, particularly when conservation and economic priorities compete.

The marine mammals we interact with have different tolerances and vulnerabilities to our activities. They can be grouped into three categories:

• Threatened populations: where even low levels of impact may be unsustainable
• Recovering populations: where some level of impact may not change population growth
• Poorly understood populations: where the effects of impacts cannot be reasonably assessed

Humans too pay a price for interacting with marine mammals. These include the costs of environmental impact studies, approval processes, management and mitigation, loss of production time or produce, equipment damage or loss and exclusion from operating in some areas. It is often difficult to reconcile perceived and real costs, although economic costs are generally easier to quantify than ecological costs.

A lack of understanding on the nature and extent of human-marine mammal interactions can affect populations of marine mammals (through late or inappropriate management), industry (through economic penalties of potentially unnecessary management restrictions or requirements) and Government (through inefficient use of research funds or the risk of poorly founded policy).