Please find attached a fish survey report from Streamline Research. The survey was kindly funded by Australian Unity Healthcare Property Trust (owner of the Beleura Private Hospital – refer attached press release for background).
My take on the key outcomes are as follows:
1. Good News: despite our concerns about on-going erosion and siltation impacts on Tanti Creek (refer to original press release), we have not lost any of the previously recorded species. Streamline Research concluded that anecdotal evidence of diminishing fish populations is most likely due to limited “invitation” flows of water during the past couple of spring migratory periods (all the recorded native species are migratory and need higher flows of water to get upstream from the bay past in-stream barriers).
Take Out: If “invitation” flows are becoming more erratic we may need to remove some of the remaining in-stream barriers so fish can migrate during smaller rain events. It may be no coincidence that the school of young Common Galaxia caught at Marchington bridge was immediately downstream of a barrier.
2. Not So Good News: a feral fish species – Eastern gambusia – was recorded in Tanti Creek for the first time. Gambusia was introduced to Australia in 1925 to control mosquitoes. But they are aggressive predators, prolific breeders and have a high tolerance for poor water quality. There are minimal effective control options. The best approach is to ensure a healthy creek habitat so native fish can be more resilient against the impacts of Gambusia.
Take-out: Peninsula residents must ensure no alien fish are released into local waterways
3. Bad News: Streamline Research elected not to sample one site (in the headwaters of the creek) due to water contamination (refer to photo in report). The pollution was coming from the Tanti Creek stormwater pipe that drains water from the light industrial/commercial area between Watts Rd and the Mornington-Tyabb Rd.
Take-out: households and businesses must take all precautions to ensure polluted water does not enter our stormwater system. Streamline Research advised that one bad pollution event can wipe out the entire fish population in a creek.
I’ve also attached a copy of a brochure on Eastern Gambusia for your information.
Now when you see a fish in the creek you will be able to identify it! A tip: the Eastern Gambusia often hang around at the surface looking like tadpoles!