Wetland warriors are small bodied wetland specialist fish and, sadly, they are among some of our most threatened organisms in Australia. Within the Murray Darling Basin this group includes; Yarra pygmy perch, Southern pygmy perch, Olive perchlet, Purple spotted gudgeon, Murray hardy-head and Flat-headed galaxias (affectionately called The Magnificent Six). These little fish were once wide spread in wetlands throughout the Murray-Darling Basin, however, a number of factors are now contributing to declining numbers:
- wetland alteration, lack of seasonal flooding and modification of natural flows.
- habitat degradation particularly loss of aquatic plants and sedimentation.
- impacts from alien fish species including carp, redfin, trout and gambusia.
Over the past 20 years, NSW Fisheries has made several attempts at breeding and re-introducing some of these little wetland warriors, with the Southern pygmy perch, Olive perchlet, Murray hardy-head and Purple spotted gudgeons, the focus of breeding efforts. Whilst there has been several successes, many attempts have failed, and we believe it is important to examine both our successes and failures to learn what has worked and what has not.
The Results to Date
Southern pygmy perch
One new wild population established
Four surrogate refuge populations established
Four Failed re-introduction attempts
Purple spotted gudgeon
One new wild population established
Three failed re-introduction attempts
Two failed re-introduction attempts
One successful re-introduction attempt (however very early days)
What has worked?
The re-introductions that have worked have a number of common factors across the species and include;
- specific habitat identification i.e. that the specific habitat requirements for the species are present at the re-introduction site.
- smaller discreet sites (streams).
- ongoing or sustained re-introductions over a number of years.
- low abundances or no alien fish species.
- good water security.
- sites with long term active management.
- engaged stakeholder group.
What has failed?
- wetland sites.
- larger sites and river systems.
- sites with less than ideal habitat.
- sites with poor water security.
- high abundances of alien species.
- one off re-introductions.
- re-introduction with low numbers.
These results highlight a couple of very important points as we move forward with more of these programs.
- If well planned and with ongoing support, reintroducing these wetland warriors can be successful, and it is a very valuable tool in the management and recovery of these species. It is important that reintroduction programs are well developed and implemented over a sustained period. Short term reactive programs have not been successful, and the future success of these activities depends on well-developed and resourced long term programs.
- Another critical component to the success of these re-introductions is the involvement of an active stakeholder group who will support and advocate for the reintroduction of fish, but also assist directly in supporting actions such as habitat rehabilitation, pest fish management, monitoring and promotion.
Getting fish in people’s faces through community engagement and support is critical to the success of these projects. As many of these species are not known to the wider public it is hard for people to care about and be involved in the recovery of something they don’t even know exists. This is why the Tri-State Alliance has been formed to raise the profile of these special fish and to hopefully attract resources to support their reintroduction into the Murray-Darling Basin.
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