Rainbow Trout, An Invasive Species for Nova Scotia?
When I was buying my fishing license this week I ran into Larry Short. He told me that two Rainbow Trout were caught in the Sackville River on opening day.Why is this significant?
Well, they are not a native spices here. Back in November, a hurricane crashed into Nova Scotia.
There was an amazing amount of rain, screaming winds and waves of over 12 meters, that is about 40 feet, were reported in the ocean off the coast of Nova Scotia.
Hurricane Noel destroyed an aquaculture facility in the waters of Liverpool Bay. They lost about $1,000,000.00 in equipment and stock. The stock in this case was big Rainbow Trout that escaped.Between Liverpool where this happened and the Sackville River are several salmon streams. I call them salmon streams but all of our Nova Scotia rivers have been severely damaged by acid rain and other human activities. The naturally breeding salmon stocks are extinct in many and endangered in all.
The Sackville Rivers Association has been working for years to rehabilitate these urban waters and re-establish a breeding population of Atlantic salmon in them. With some success, I might add. Nevertheless, it is a fragile victory.These two Rainbow Trout could disrupt the whole program if they were carrying a pen-born disease. It could be a disaster if they are the harbingers of breeding pairs pioneering local waters.
I asked Larry if these fish were not triploid as much fish farm stock is.
Triploid fish are sterile because of a genetic manipulation. They have three sets of chromosomes instead of two (diploid) which is normal.
The advantage to fish farmers of using triploid fish in aquaculture is their rapid growth and weight gain. The disadvantage is their susceptibility to deformities and disease. It also means that escapees cannot reproduce and become an invasive species.
Larry told me that the problem is that even though triploid fish are being raised, not all of them are in fact sterilized. As in anything, there is a margin of error.
What does it all really mean?
Well, in talking to my fishing friends not all of them are unhappy about the fish escaping and entering our rivers. About half of the guys are looking forward to catching them if they can.
They point to Cape Breton, which has Rainbows and Steelhead in the rivers now, apparently from aquaculture escapees getting into the Bras D’Or Lake over the last twenty years or so. I have gone fishing for Steelhead there myself. (I did not get any so went salmon fishing instead).
Others fear the big picture. A new invasive species that just might be the straw that breaks the Salmon’s back.
The Rainbows are out of the cage now so only time will tell. It is too late for our opinions on the subject to have an effect but I would still be interested in hearing what you think.
Image of fish after storm on Beach Meadows Beach from the Queens County Times
Labels: Hurricane Noel, rainbow trout, Sackville River
posted by Steve Dobson at
02:00
11 Comments:
So will you be catch-and-releasing these if you catch any, or will there be rainbow trout barbecues at the dobson household this summer? :)
Yup, I've eaten and enjoyed rainbows in the past. They aren't native to Scotland and aren't known to breed there, but there are quite a few stillwaters stocked with them each year, and they're a popular catch, because unlike the brown trout, you can actually make a meal rather than a snack out of them.
I have enjoyed great steelhead fishing in Cape Breton. I am hoping that these fish enjoy the south and easten shore rivers and take up breeding in them. My understanding is that the attempted plantings of Rainbow trout have not worked out well, but the accidental planting in Cape Breton has been pretty good.
Hope this works out just as well.
Heading to whitepoint and hope to catch a few!
Fishhawk
Brad,
Are you serious or just trying to stir up some commotion? 'Cause if you are serious you should think it through a bit.
RDG
I wish I knew the secret to connecting with those C.B. Steelhead Brad.
PS -You do have a knack for causing a commotion. RDG may be on to you.
Andrew, I was under the impression that those Loch Levin trout got to enormous sizes. Aren't they the genetic strain that was planted here in Canada?
Cheers,
Steve
Steve:
I don't mean to split hairs, but the aquaculture operation was in Liverpool Bay near Coffin Island and the dead fish washed up on Beach Meadows Beach.
BTW, I think I saw one of those Rainbows in the Medway last weekend. I was rowing my boat upstream to where a brook runs in and I had my line out behind - not too long a line - just a regular cast - say 40 feet. The fly was a variant on a Chili Pepper tied with a Muddler head instead of a bead. It was "waking", that is, making a commotion on the surface. I thought I saw something move near the fly, but I wasn't sure because it was windy and there was a light chop on. I laid down the oars and picked up the rod just to check - nothing there, so I took up the oars again.
Before I made a sweep, a fish leapt out of water, about a foot or two over my fly. I only had a second's glimpse, but I was looking directly at it, not peripherally. It was about 20" long and torpedo-shaped - funny color - kind of greenish with a bit of red. If I had to guess, I'd say a Rainbow Trout - and a damn fine one, too!
Steve:
I forgot - you want opinions - as usual, I have one. The debate about invasive species is a complex issue... That being said, I feel this particular incident is fairly straightforward. As you point out, the milk is spilt. There is no feasibility in a "seek and destroy" operation to try and purge our pristine waters. It's impossible to even anticipate where they are, let alone try to catch them all. The published figure was half a million fish released.
So, if your question is what will I do if I catch one? I will do what I always do... if my wife has asked me to bring one home for supper, (she does this about twice a year) I will kill it, if not, I will let it go.
Quite sad from my point of view. I've read numerous reports of rainbow trout beginning to show up on the east coast....particularly the Newfoundland/Labrador area.
Rainbows are a particularly ferocious species that once in a system are a terror to remove, and they easily out compete resident species through eating either them, or their food source. Either is detrimental to the native populations. I've seen several great brookie streams here in Ontario DIE due to the stocking of rainbows, which return each year to the rivers to spawn, much like atlantic salmon and sea trout do.
On top of that, the MNR here in Ontario, as well as many many steelheaders have taken to liking this non native species so much that they are improving various areas to assist in the natural reproduction of rainbows in various river systems here. Some, not all, but some of these "improvements" are detrimental to the survival of various native species here.
Don't get me wrong.....I do enjoy fishing for rainbows, but that is only because our native fish populations have been so disturbed or extirpated that rainbows are all that are left to target now.
Thanks for all of your thoughts folks and your re-orienting the location for me.
Cheers,
Steve
I have never seen waves that high, quite scary.
I was wondering if there has been any update on the rainbow problem since this post? I would hate to see it destroy the salmon, they are one of my favorite fish.
We can avoid this kind of problem if we stand together to get the fish farms out of our shared oceans - save wild fish - save wild BC salmon
Alexandra Morton is leading the way in a GET OUT of Migration!
(out of our ocean and into closed containment)
sign her letter
www.salmonaresacred.org
Thanks very much
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