Date: 09 December 1998
From: Jennifer E. Collins <jcollins@cadmin.nsac.ns.ca>

To: AQUA-L@killick.ifmt.nf.ca

QUESTION:

I am trying to spawn some shellfish (quahogs, oysters, mussels, and
clams). Unfortunately, I received the animals after the fall bloom,
so they had already spawned. Presently, I am reconditioning them
so I can get them to spawn early in the winter. I am, however, doing
this in artificial seawater. Does anyone have any experience in
conditioning shellfish and keeping animals on a long term basis in
artificial seawater?

Jennifer Collins

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COMMENTS 1:

For several years we (Provincial Government Shellfish Hatchery at Pleasant Point, Nova Scotia, Canada) conditioned, spawned and grew out Ostrea edulis using low salinity water augmented by commercial 'sea salt' preparation. We were able to obtain between 750,000 and 1,200,000 spat in our small facility during the 1970's and early 1980's. We also raised C. virginica, and M. mercenaria.
For interest, once we were asked to produce some C. virginica after ours were all spawned out. I went to the local grocery store found that the oysters on display had been packed before spawning. I bought two dozen, conditioned them (over six days) and produced 500,000 viable spat.

Kevin Henderson
Nova Scotia School of Fisheries and Aquaculture
<HENDERSK@gov.ns.ca>

***************

COMMENTS 2:

Contact the Haskin Shellfish Lab (Rutgers) in New Jersey, and the National Marine Fisheries Service Shellfish Lab in Milford Connecticut, USA.
I am aware of an experimental project that grew oysters from eyed larvae to seed (approx 1cm) in artificial seawater in a recirculating hatchery experiment. The hatchery was not designed for oyster production, so the outcome appeared to be an exercise in futility or extravagance or something that seems to defy logical explanation. In that stage (from larvae to seed) it was not mineral or trace element concerns that predominated (something you might expect in that particular formula of artificial seawater) but rather bacterial infection, inadequate flow rates, residence times, and flow direction through the tanks. In short, it was all wrong.
University of Delaware ran a project growing oysters in recirculated (real) seawater, resulting in the much ridiculed $64.00 oyster (referring to yield versus capital and operating costs)
Reed Mariculture in California may offer you some help. They have a
website. Also, contact Dr. Chris Taylor (?) at Oregon State University.
Also, Yves Le Borgne, at SATMAR at Barfleur on the Channel coast of France may help- see the chapter "Controlled reproduction of bivalve molluscs" in Aquaculture, Volume 1 , ed Barnabe, Ellis Horwood Publisher. Univ. of Hawaii ran some fluidized bed upweller cylinders for oyster culture using shrimp pond water.
At LSU Civil Engineering they developed the HISTAR system of algae culture and worked with a fellow in Georgia that was using recirculating upwelling tubes to grow clams.

Ted Ground

ground@thrifty.net
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