Pacific NW hatchery problems

[Mark]

To get this topic started I am posting these comments and questions from Quercus for comment by larvadeostion !

I was reading in the BCSGA about your current problems. First I should say that I was always surprised how few problems the West Coast hatcheries had compared with here where coastal water is more often than not, rather poor from the point of view of larval culture. I put the success down to the fact the most of you are taking your water from enclosed or partially enclosed waters where natural phytoplankton blooms do a good clean up job. It seems that this process has somehow ceased to work.

I have had reports from clients and friends around the globe who are all finding larval production more difficult in the last 2 years. This includes places as far flung as Florida, Norway and South Australia. I don’t suppose there can be one unifying factor but it does seem odd that things are particularly bad of late. The only people who have not suffered are those taking their water from marine wells. There are lots of kinds of marine wells but the lucky ones are those people who have water that is old, like for example in Bouin, France where the water is believed to be 100 years or more and yet not contaminated with excesses of heavy metals. There are a cluster of hatcheries there who are working apparently without problem. I don’t know very much about it but would imagine the water is highly mineralised and contains no organic material that would support or encourage the growth of pathogenic bacteria.

I see that Alan Barton is hoping to tackle some of your problems. My guess is that intensive clean up won’t work but it might be possible using a pro longed bio filtration process to eliminate some of the organic substances that support the bacterial problem be it Vibrio or something else. One remedy we have here is to take only small amounts of new water from the shore and store it in open ponds for as long as possible, re-using a large amount of it. This works but it would be difficult for you to emulate as you have nowhere to build acres of blooming ponds, at least I don’t think you have.

I am attaching a bit of correspondence I have had with John Thain who has been very helpful in the past looking at various problems with larvae diet and management. What it does tell you which may be useful is those things which have not worked, so you might choose to spend less time looking at those and more on aspects of bioremediation.

I had hoped to start up some sort of a round robin correspondence where everyone pooled their experiences but I simply haven’t got time”! It would be good to get a team effort together rather than press on as individuals, but I can’t think how to do it!

I would like to here some more from you, particularly whether my description of the pattern of the problem matches your own experience

[Mark]

Newspaper article link supplied by Jim Donaldson June 2009
http://seattletimes.nwsource.com/html/l ... rs14m.html