<
https://theconversation.com/the-worlds-second-largest-freshwater-crayfish-was-once-plentiful-in-australias-longest-river-were-bringing-it-back-236520>
"Murray crayfish once thrived in the southern Murray-Darling Basin. The species
was found everywhere from the headwaters of the Murray and Murrumbidgee Rivers
in the Australian Alps all the way down to Wellington in South Australia.
For thousands of years, First Nations people managed harvesting sustainably.
But crayfish stocks crashed after European settlement. This was partly due to
commercial and recreational harvest, which began in the late 1860s. At its peak
in 1955, 15 tonnes of Murray crayfish were taken from the river in New South
Wales and sent to markets in Melbourne and Sydney.
In South Australia, the commercial fishery was unsustainable by the 1960s and
the species was no longer targeted. In the 1980s, Murray crayfish became a
protected species in the state. But the damage was done.
Over-harvesting was not the only problem. Murray crayfish prefer free-flowing,
oxygen-rich water, so they suffered from efforts to regulate river flows using
dams and weirs. Poor water quality, including pollution from pesticides and
other agricultural chemicals, made matters worse.
Murray crayfish disappeared from South Australia sometime in the past 40 years.
Targeted surveys over a five-year period couldn’t find them anywhere in the
state.
But that all changed in the winter of 2023 when our reintroduction program
began. Now we’re preparing for the third release of crayfish and there are
positive signs many crays from earlier releases are still going strong."
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
