I’ve been asked by several followers of this blog to post any new information about the CAST Program. CAST stands for the Collaboration for Atlantic Salmon Tomorrow, and the collaboration is one of private industry, namely Irving and Cook Aquaculture, the University of New Brunswick, and various not for profit organizations including the Miramichi Salmon Association.
CAST has done a number of things such as installing special cameras to count the number of migrating salmon in the Miramichi, but it is best known for a plan called Smolt to Adult Supplementation or SAS. Under this plan wild smolts are gathered from the river and reared in a hatchery until they are ready to spawn. Once the spawning time approaches the smolts – now grown to adult salmon – are released into the river from which they came as smolts, and they will assumedly continue up the river to spawn naturally along with the wild fish that are present.
This concept is already in use to try and restore salmon and steelhead in rivers where the runs are in imminent danger of extinction, but it has not been done in a river like the Miramichi where runs have been greatly reduced from historic levels, but are not in immediate danger of extinction. There are people who want to use this program to bring back historically large runs, and there are others who just want to do enough to make sure the runs remain viable in the future. There are detractors of the program who are simply against stocking in any way. These people feel that since there is nothing really wrong with the Miramichi, and that it doesn’t need supplementation, instead we need to figure out why returns from the sea are at significantly lower percentages than they historically were.
PEER Review – the opposition to the SAS program has been waiting for the completion of a peer review by a panel of scientific experts from various backgrounds. While there is no formal agreement on this point, assumedly a positive peer review would open up the path for this project.
This peer review panel met for two days on January 22-23 2018 to discuss the proposed program. The process has resulted in a March 2018 Science Advisory report. As a director of the Miramichi Salmon Association I was given an advance copy of this report which you can read here.
The Potential Benefits – Overall I think the DFO likes the idea of the program, but perhaps for slightly different reasons than one might suspect. DFO did not address increasing runs of salmon to please anglers. On page 3 of the report they do list four benefits that are of interest to them. These more or less boil down to just seeing how effective the SAS technique can be applied to the current situation in the Miramichi which is one of still viable but greatly reduced runs. No one really knows how well this will work, but DFO sees value in finding out.
The Risk and Reward – there are identified risks, and the panel came up with 5 of them, also listed on pages 2 and 3. These 5 really boil down to 2 which are the risk of transferring disease from the hatchery to the wild, and risk of reducing the percentage of fish in the population which are 100% certifiably wild. Hatchery techniques have been used on the Miramichi for more than 100 years, so the river is not without some hatchery influence, if in fact there is any difference between the hatchery fish and the 100% certifiably wild fish. I’m going to try and not editorialize this report too much, but this is one area where it seems to me that some folks go a little overboard. I read recently about natural selection beginning with the fish mating with other salmon of their own choosing, and picking just the right spot on the gravel bar to be at the lowest possible risk of being wiped out by an ice flow. It just seems very far-fetched to me that there would not be a very high percentage of pure serendipity in both these processes. We know that female salmon eggs are often fertilized by several male fish including parr. We also know that nothing is less predictable than where or when a tumbling piece of ice will contact the bottom of the river. The picking of a spawning site has to be instinctual. When could the fish every have learned where to build a redd? Most of them only spawn once in their life, and none of them get to see how their redds faired come spring. The fish in the SAS program are starting out as completely wild smolts from the river of their birth. It would certainly seem reasonable that whether raised in a hatchery or at sea that their choice of the location to build a redd would not be altered by where they did their feeding previous to returning to the river to spawn.
I’ll probably take some shots for that one, but I’m confident that some of the fishery scientists will agree with my thinking. I am, also sure that no one knows these things for certain. We do know that by having only completely wild fish spawning that we do everything possible to eliminate all risks, but on the other hand we have seen great success with hatchery stock enhancement including self-sustaining reintroductions in several rivers. How low do we let a population get before we turn proactive? Hopefully not so low that it is too late.
Mitigation Measures – The report listed a number of suggested mitigations measures. Again these really boiled down to two basic areas: the first were steps to reduce the chances of disease being transferred to the wild, and the second was to make sure that the stocked fish didn’t become such a large percentage of the production in the river as to outnumber the wild fish. On the surface all the few things that they listed seemed entirely doable.
Summary – given this report and its constructive list of mitigation measures – most of which I think the CAST team had already contemplated – it is hard to see how the program will not be given the green light to proceed as planned.