Estuary life in the fast drain
June 17, 2010 by BayKeeper
Filed under Featured, Wild Things
The Cowderoy Street drain outfall crossing West St Kilda beach is an unlikely tourist attraction. But Baykeeper has found it brimming with fish during recent guided walks for Elwood Primary School families. Schools of juvenile Yellow-eyed Mullet ( Aldrichetta forsteri) and Small-mouthed Hardyheads (Atherinastoma microstoma) were regularly found. The recent recent rains have brought extra nutrients and oxygen to Bay estuaries… good news for fish!
High tide at Cowderoy - June 2010 (pic by Andrew McCutcheon)
Not surprisingly, the presence of these schools of small fish has put the local penguins in a pretty good mood. Earthcare St Kilda has recorded highest ever numbers of penguins breeding at St Kilda during the 2009-10 season, with the population estimated at around 1,200. At the same time, the average weight of adult penguins has been lower than usual, perhaps due to increased competition when finding a feed. The guided walks also found Nankeen Night Herons (Nicticorax caledonicus) patiently working the outfall.
It was great to see this life still in St Kilda despite the Port of Melbourne shipping channel dredging in the Lower Yarra River in recent years. The dumping of more than 3 million M3 of contaminated Yarra sediments in the bay may put the food chain, and particularly top order predators such as penguins at risk. The effects may take some time to show…. but so far so good!
Hi BayKeeper,
This is good news. There was some great data collected on the water quality of the Cowderoy St drain a few years back by Nicki from Earthcare. I don’t think she regularly noticed fish in the drain while testing with her Water Watch kit every Saturday morning.
I wonder if we could find the results and get some readings on just how the outflow has improved?
Julian
Too right Julian! I’m hoping to find someone who’ll who’ll take up where Nicki left off. Not necessarily weekly testing though. I reckon once a month would be fine. I know Nicki regularly recorded very high phosphate levels, possibly due to a leaking sewer. Since Nicki completed her monitoring there has been some major structural work on the drain. Would certainly be interested to learn if the water quality has improved.
WOW!!! I was just in the middle of a giant school of fish that looked just like the ones in the pictures and they were forming a mass circle or fortification around me but i think they were using me as protection against those damn seagulls because the sea gulls were having a mass feast until i came in, it was the most amazing thing and i’m going back this afternoon for more.
There were thousands, hundreds and thousands of them…