THE CASE OF THE MISSING ANCHOVY
Anchovy are an important prey item of Little Penguins and numerous fish species in Port Phillip Bay. They’re also great on pizza!
So Channel Deepening through their spawning habitat in Hobsons Bay and the Yarra is cause for concern, as is disposal of contaminated dredged sediments in the Bay. In response to these concerns, a Baywide Anchovy Survey is being conducted over several years.
Anchovy larvae comprised 74.5% of total fish larvae sampled in PPB during November to January of 2007-08. Curiously, just 6 months later, the Baywide Anchovy Study Sub-Program conducted during June-July 2008 recorded no Anchovy in the 0+ (first year) age class.
The Goomai grab-dredge in the Yarra
Explanations cited for the failure to find first year Anchovy are:
1. Anchovy of 0+ years of age occur in regions of PPB not sampled;
2. Fish of this size may not have been sampled due to loss through the net;
3. A recruitment failure may have occurred beyond the larval stage.
If anchovy recruitment from the 2007- 2008 season has failed, the effects on penguin foraging would initially be absorbed by the presence of the 1+, 2+, and 3+ year classes. Increased penguin preying on older age class Anchovy is likely to reduce the mature (reproductive) Anchovy population. Combined with the absence of the 0+ age class Anchovy, this is likely to impact on Anchovy recruitment in subsequent seasons.
The degree of impact of the dredging program on penguin prey species such as Anchovy, like many other aspects of the project, will often take more than a year or two to show up. The results of the 2009 Anchovy surveys are sure to be really interesting.
With the knowledge that we have possibly lost a generation of anchovy – has the Port of Melbourne given a reason as to the reason why they have not located the teenage ‘chovies and will they continue maintenance dredging of the Yarra over the next two years and possibly effect future anchovy breeding. What steps is PoM putting into place to protect our anchovy and everything else that eats them?
As I recall the June 2009 Channel Deepening Community Liaison group meeting, the PoMC put the view that the missing Anchovies might just have been somewhere else in the Bay.
But ultimately, Fisheries Victoria is responsible for conducting and reporting on the annual Baywide Anchovy Surveys. Given that the last survey occurred in June – July 2008, we should expect another report soon.
Could everyone please look out for and record Gannet activity in the Bay, this time last year I was photographing hundreds of birds feasting on ‘chovies… gannets, terns, seagulls, pacific gulls, even the pelicans came for the feast. This year I have only seen one feeding frenzy along Seaford Beach.
I believe the report on the July 09 survey of the Anchovy will be out at the end of September. I am waiting to interview Michael Holloway on the results… which will be broadcast on Radio 3RPP 98.7 FM on Thursdays 4 – 6 pm
Thanks for drawing our attention to this Alison. Gannets dive-bombing fish have got to be one of the most spectacular, wild encounters available to the average beach stroller. Your call for other Bay lovers to look out for and send in Gannet activity is a great idea. The importance of collecting written data on wildlife can’t be stressed enough. IT’S HARD TO WIN AN ARGUMENT WITHOUT FACTS TO SUPPORT OUR CASE.