QUESTION:
Can anyone with experience on rearing oysters of the species Ostrea edulis (European flat oyster) tell me what algae (size and species) culture the oysters prefer when reared in a hatchery/nursery?
Anne-Marie Bomo <anne-marie.bomo@nlh10.nlh.no>
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COMMENTS 1:
We found that a mixture of species gave quite superior results to the use of any one type.
Those that we used regularly were:- Tetraselmis suecica, Monochrysis galbana, Isochrysis lutheri, Chaetoceros sp. (don't remember which one), we experimented with others as well.
We found that the time of harvesting of the algae made quite a difference to the results, typically they should be harvested, before the exponential phase flattens out.
We also developed a methodology for not changing the water through to settlement, if this interests you, please contact directly me at my E- Mail or otherwise:
Shawn Prescott
Fish-Vet Inc.
12620 Ivy Mill Rd.
Reisterstown
MD 21136 USA
Tel 410.526.0573
Fax 410.526.0574
<fishvet@jagunet.com>
Internet pages. http://www.jagunet.com/~fishvet
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COMMENTS 2:
I've had good results with a tropical strain of Isochrysis (T-Iso or C-Iso), adding in some Chaetoceros gracilis toward the end of the larval phase, by which point the larvae are clearing down close to 100K cells/ml/day. Don't have exact measurements here, but my feeling is that the Iso is maybe 6-9 microns in diameter, and Chaetoceros a little bigger.
Will Borgeson <wdborgeson@ucdavis.edu>
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COMMENTS 3:
At our Sea Farms hatchery we used Isochrysis galbana and Monochrysis lutheri for the larvae. Thalassiosira pseudonana can be used for later stage larvae and spat. Our algae room would get too warm for I. galbana in the summer, so we switched to Pseudoisochrysis (Tahitian strain" during the warm months. A very good reference is "Culture of bivalve molluscs - 50 years experience at Conway" by P.R. Walne.
clangell <clangell@eskimo.com>
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COMMENTS 4:
You do not state the age/stage/size of the oysters that you need to feed. In general the same algal species can be used for any bivalve species. We have had good results with larvae with a mixture of Isochrysis galbana (or Tahitian Isochrysis) with a diatom (either Thalassiosira pseudonana 3H or Chaetoceros calcitrans) and Tetraselmis suecica. I suspect that the exact species is not too important - but you will always get better results if you feed a mix of species. With spat and adults a mix of Tetraselmis and the diatom Skeletonema costatum is fine. This mixture can also be used with success with late larvae .
Brian Ottway
Course Director:Aquaculture Courses
Regional Technical College, Galway
Dublin Road,Galway, Ireland.
tel:+353-91-753161
fax:+353-91-751107
<BOTTWAY@aran.rtc-galway.ie>
Special Interests: Micro-algae,Shellfish Aquaculture.
College Web Site: http://www.rtc-galway.ie
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