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12/27/20

Tasmanian Freshwater Lobster

The Tasmanian giant freshwater lobster, also called the giant freshwater crayfish or Astacopsis gouldi, is the largest freshwater invertebrate in the entire world. They can grow up to 5 kilograms (about 11 pounds) and over 80 cm long, and can live up to 60 years. These giant invertebrates are endemic to Tasmania and live in rivers and creeks that flow into the Bass Strait, though recent local extinctions have shrunk the number of rivers they live in. In these rivers, adults live in still, deep, cool water under rocks, logs, and overhanging banks. Like many aquatic animals, they prefer clean streams.

Problems facing the Tasmanian giant freshwater crayfish include poaching and habitat loss, and these problems are exacerbated by the large lobsters slow reproductive rate. Although it is hard to count aquatic animals, research shows that there are about 100,000 lobsters left. Almost none of those are full grown, as the larger lobsters were mostly wiped out in the last century. In 1998, a ban was placed on the fishing of these lobsters. However, because of their slow reproduction rate and the fact that it takes up to 14 years for lobsters to reach sexual maturity have prevented the population from returning to its usual numbers. Larger lobsters that can reproduce are easily caught, making them threatened by illegal fishing, and young Tasmanian giant freshwater lobsters are threatened by habitat loss. This is caused by agricultural expansion, forestry operations and a decline in water quality. A recent increase in sedimentation blocks the crevices young lobsters need to hide from predators.

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Image by Henry Zwartz

By helping to improve the Tasmanian giant freshwater crayfish’s habitat and the water quality, we can also help the other species who have been affected by habitat loss.

Without the creation of protected areas where Tasmanian giant freshwater crayfish can live without being hunted, populations will certainly decline. To help this lobster, we must enforce the fishing ban, create research surveys, protect their habitat, and manage the vegetation near the water, thus benefiting the waterways and their species. The people around these rivers can help by protecting the vegetation near rivers, not fishing for lobsters and reporting illegal fishing, and joining local organizations that work to protect native threatened species. Even if you don’t live in Tasmania, these tips also can help protect other endangered species in your area.

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Image by The Wildiaries

Image by The Wilderness Society

Image by Dan Broun

Image by Henry Zwartz

Works Cited

Tasmanian Giant Freshwater Lobster (Astacopsis gouldi). (n.d.). Retrieved October 09, 2020, from https://www.environment.gov.au/resource/tasmanian-giant-freshwater-lobster-astacopsis-gouldi

Zwartz, H. (2017, October 23). Clock ticking for lobsters 'as big as a small dog'. Retrieved October 09, 2020, from https://www.abc.net.au/news/2017-10-22/tas-giant-freshwater-lobster-fears-for-iconic-species/9072950

Cover image by Dan Broun