Threats

About Marine Threats



Pollution, coastal development, introduced pests and overfishing. The dangers facing Victoria's marine environment are the same the world over and the near-shore coastal environment where human populations are concentrated is under particular pressure. If we are to ensure a healthy, functioning marine environment for the future, filled with the diversity of species that we see today, we must take a more active management approach. Governments, industry and the wider community all have an important role to play in ensuring there is a balance between exploitation and protection. Victoria has the opportunity, through legislation, planning and community commitment, to restore degraded habitats and overexploited species, but more effective and timely action is needed.

River pollution and sedimentation

River pollution and sedimentation enter our bays and coast, often as a result of changes to upstream catchment areas by removing trees, dumping wastes, diverting and damming waterways, extracting water and so on.

Oil spills

Because toxic petroleum compounds float on water, oil spills have a much greater impact on intertidal plants and animals than those living underwater.

Coastal development

Coastal development such as land reclamation, canal development, marina construction, and dredging.

Beach litter

Fishing debris and bait box bands collar and kill seals, plastic bags kill turtles when they mistakenly eat them, thinking they are jellyfish.



Overfishing

For some Australian fisheries, the problem of overfishing is compounded by damage to the habitat itself. Inefficient and destructive techniques such as bottom trawls and dredges damage seafloor habitat and capture large amounts of non-target animals. The killing of large amounts of fish may have far ranging impacts on interdependent species such as prey or predators, and may affect habitat-forming plants and animals.

Toxic organic compounds and heavy metals

Toxic organic compounds and heavy metals such as copper and mercury, cadmium, zinc and lead can affect marine animals at low concentrations. Many build up in the tissues of animals in a process known as bio-accumulation.

Global warming and long-term climate change

Air and sea temperatures are predicted to rise by several degrees over the next century, based on current greenhouse gas emission rates, as will UV levels. Tasmanian coastal waters have risen by about 1.5 0C since the 1960s and species never previously seen, such as the barren-forming Black Sea Urchin, have recently become common. Algal species that were once abundant in cool waters, Giant Kelp for example, now have a restricted range.