In a previous blog, I wrote about the recent Yarra pygmy perch releases we undertook out at the newly restored Pick Swamp, situated within the Piccaninnie Ponds Coastal Wetland (PPCW) complex. To refresh your memory, the fish releases took place in last October and November and marked a tremendous milestone in the conservation of the Yarra pygmy perch in the South East region. Committed staff and students at Millicent High School introduced several hundreds of Yarra pygmy perch into their new home at Pick Swamp, after breeding them in captivity for over 6 years. Last week, follow up monitoring was undertaken to assess how the Yarra’s had taken to their new environment.
To maximise survival rates and optimise their chances of establishing in Pick Swamp, Yarra pygmy perch were released at two locations; a semi-contained 100 m long section of the swamp and into a 2 x 2 m ‘soft release enclosure’, situated in a far more open area of Pick Swamp. Follow-up monitoring is crucial in determining the post-release survival rates and assessing whether additional releases are required. Fyke nets were set overnight in the 200 m stretch of swamp with the anticipation that capturing just one or two individuals in this large expanse of water would be a great result. We were therefore delighted to return the next morning and catch over 20 Yarra pygmy perch across three nets, some of which were only 10-12 mm in total length.
While this critically endangered species has not been recorded previously in Pick Swamp (since its restoration in 2006), Yarra pygmy perch have been detected in a nearby karst rising spring within the PPCW complex (Crescent Pond). However, with regular monitoring at Crescent Pond recording consistently low (or no) captures since 2012 and there being no evidence of recruitment since 2008, it is highly likely that this population will (or has) become locally extinct.
Given the current status of Yarra pygmy perch in Crescent Pond, establishing a self-sustaining population in Pick Swamp is therefore of huge significance. The smaller individuals (10-12 mm total length) detected during last week’s follow-up monitoring, could very well represent the first wild recruits in the whole Piccaninnie Ponds Coastal Wetland complex since 2008. A very promising result! This population will continue to be monitored throughout 2015 with potential for further releases to occur in autumn.