1 JUNE 1999
Date: 23 April 1999 01:18
From: Paul Neima <paul.neima@ns.sympatico.ca>
To: aqua-l discussion group <aqua-l@killick.ifmt.nf.ca>
QUESTION:
Does anyone on the list have any suggestions for how to treat oyster
seed to prevent settlement and fouling by mussel spat? I know that lime and saturated brine dips are effective in killing starfish and sea
squirts but I don't think they are effective with mussel spat. I have
also heard that heat treatment will kill off mussels without damaging the oysters. I'm hoping to be able to come up with a dip treatment that can be used for 5-10 mm oyster seed during the time when mussels are spawning and setting.
Paul Neima
***************
COMMENTS 1:
In the 1970's I was heavily involved in an oyster farming project in the Bras d'Or Lakes. We experienced serious problems with mussel fouling on the scallop shell media we are using for suspended oyster culture.
After some time and numerous trials using various methods we observed the following which may be of benefit to you.
Oyster and mussel spatfall due not occur at the same time. Therefore predicating spatfall of both species and the timing of placement of collectors is a useful and effective management tool.
Oyster spat can handle air drying much better than mussels. Pulling your collectors up above the water on hot dry days will kill the mussels but not the oysters. This should be done carefully depending on the age and size of the spat until you develop your own rules.
Collectors having high density oyster spatfall did not accumulate mussel spat. As yearlings, scallop shells having 10 or more oysters per shell did not accumulate new mussel spat. We thought that perhaps the oysters were binding up the mussel larvae in their fences, hence no mussel spat on those individual collectors. So we started rejecting collectors that had a low density of oyster spat.
Phil Drinnan
pdrin@atcon.com