Sea Lice and Fish Farms
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bones - I am sure you have already seen all the posts - many pages worth by numerous posters - detailing temporal and geographical variation - and the reasons why that changes - and is site and time-specific. So - this should instead be a question asked by our regulators to the industry that is proposing to impact wild stocks. What you are doing is called "shifting the burden of proof".
However, here is one site and time-specific reference that should be used under the precautionary approach to set-up studies to quantify that impact:
http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2109.2001.00627.x/abstract
Salmon lice infection of wild sea trout and Arctic char in marine and freshwaters: the effects of salmon farms
P A Bjùrn1, B Finstad2 & R Kristoffersen1
1The Norwegian College of Fishery Science. Breivika. N-9037 Tromsù, Norway
2The Norwegian Institute for Nature Research, Tungasletta 2, N-7485 Trondheim, Norway
Correspondence: P A Bjùrn, Norwegian Institute of Fisheries and Aquaculture, N-9291 Tromsù, Norway.
E-mail: paal-arne.bjorn@®skforsk.norut.no
Abstract
The abundance of salmon lice and the physiological effects of infection were examined in two stocks of sympatric sea trout and anadromous Arctic char in northern Norway. One stock feed in a coastal area with extensive salmon farming (exposed locality), while the other feed in a region with little farming activity (unexposed locality). The results showed that the lice infection was significantly higher at the exposed locality, at which the mean intensity of infection peaked in June and July at over 100 and 200 lice larvae per fish respectively. At the exposed locality we also observed a premature return to freshwater of the most heavily infected fish. Such behaviour has previously been interpreted as a response by the fish to reduce the stress caused by the infection and/or to enhance survival. Blood samples taken from sea trout at sea at the exposed locality showed a positive correlation between intensity of parasite infection and an increase in the plasma cortisol, chloride and blood glucose concentrations, while the correlations from sea trout in freshwater were more casual. Several indices pointed towards an excessive mortality of the heaviest infected fish, and 47% of the fish caught in freshwater and 32% of those captured at sea carried lice at intensities above the level that has been shown to induce mortality in laboratory experiments. Furthermore, almost half of all fish from the exposed locality had lice intensities that would probably cause osmoregulatory imbalance. High salmon lice infections may therefore have profound negative effects upon wild populations of sea trout. At the unexposed location, the infection intensities were low, and few fish carried more than 10 lice. These are probably within the normal range of natural infection and such intensities are not expected to affect the stock negatively.
However, here is one site and time-specific reference that should be used under the precautionary approach to set-up studies to quantify that impact:
http://onlinelibrary.wiley.com/doi/10.1046/j.1365-2109.2001.00627.x/abstract
Salmon lice infection of wild sea trout and Arctic char in marine and freshwaters: the effects of salmon farms
P A Bjùrn1, B Finstad2 & R Kristoffersen1
1The Norwegian College of Fishery Science. Breivika. N-9037 Tromsù, Norway
2The Norwegian Institute for Nature Research, Tungasletta 2, N-7485 Trondheim, Norway
Correspondence: P A Bjùrn, Norwegian Institute of Fisheries and Aquaculture, N-9291 Tromsù, Norway.
E-mail: paal-arne.bjorn@®skforsk.norut.no
Abstract
The abundance of salmon lice and the physiological effects of infection were examined in two stocks of sympatric sea trout and anadromous Arctic char in northern Norway. One stock feed in a coastal area with extensive salmon farming (exposed locality), while the other feed in a region with little farming activity (unexposed locality). The results showed that the lice infection was significantly higher at the exposed locality, at which the mean intensity of infection peaked in June and July at over 100 and 200 lice larvae per fish respectively. At the exposed locality we also observed a premature return to freshwater of the most heavily infected fish. Such behaviour has previously been interpreted as a response by the fish to reduce the stress caused by the infection and/or to enhance survival. Blood samples taken from sea trout at sea at the exposed locality showed a positive correlation between intensity of parasite infection and an increase in the plasma cortisol, chloride and blood glucose concentrations, while the correlations from sea trout in freshwater were more casual. Several indices pointed towards an excessive mortality of the heaviest infected fish, and 47% of the fish caught in freshwater and 32% of those captured at sea carried lice at intensities above the level that has been shown to induce mortality in laboratory experiments. Furthermore, almost half of all fish from the exposed locality had lice intensities that would probably cause osmoregulatory imbalance. High salmon lice infections may therefore have profound negative effects upon wild populations of sea trout. At the unexposed location, the infection intensities were low, and few fish carried more than 10 lice. These are probably within the normal range of natural infection and such intensities are not expected to affect the stock negatively.
This is a study done on in coming fish....100-200 infection. I know you don't fish AA. but pink salmon entering in to the also show 100-200 lice infection. It was a study you didnt read, but rejected. It showed that because pink salmon are on a two year cycle, that they cannot develop the antibodies required to rid themselves of the parasite. Unlike Chinook and Coho return on a 3-6 year cycle thus allowing them to develop tho anti body and past it down generation to generation.
Again with the hundreds of papers you've shared is the any numbers that show salmon farms influence out going salmon?
I get your frustrated but....i can stand here and say they don't..... Do you have value of any kind? Till then your just pointing your finger
Again with the hundreds of papers you've shared is the any numbers that show salmon farms influence out going salmon?
I get your frustrated but....i can stand here and say they don't..... Do you have value of any kind? Till then your just pointing your finger
7.5 cubs not tigers...
and the "10" from this study are on much larger fish than early outmigrating juvie pink and chum smolts: 120-210g sea trout, 282-464g char. Remember that juvie pinks outmigrate at ~0.3g and in Terrin's pic are likely only ~5g.
Mortality from sea lice is estimated as no MOTILE lice per gram of fish. These fish are like 100 times larger than the juvie pinks by weight - so divide the "10" by "100" - and what do you get for mortality limit of louse per gram of fish?
Thanks for pointing that out. That looking at the science stuff is kinda cool - don't you think?
and the "10" from this study are on much larger fish than early outmigrating juvie pink and chum smolts: 120-210g sea trout, 282-464g char. Remember that juvie pinks outmigrate at ~0.3g and in Terrin's pic are likely only ~5g.
Mortality from sea lice is estimated as no MOTILE lice per gram of fish. These fish are like 100 times larger than the juvie pinks by weight - so divide the "10" by "100" - and what do you get for mortality limit of louse per gram of fish?
Thanks for pointing that out. That looking at the science stuff is kinda cool - don't you think?
Last edited:
GLG
Well-Known Member
This is the claim that you have made are you now saying that you didn't? That's odd.
So
you posted a paper that has no significant interest in the question, brilliant. How many out going smolt die at the hands of fish farms? You still are not answering all you are doing is finger pointing..." Look fish farm".
fogged in
Well-Known Member
Bones
Are you looking to physically count the number of smolts killed by Fish Farm Sea Lice?
Would be pretty simple to remove all the disease infested, sea lice infested Open net Cage Fish Farms in the Broughton and see what returns too so why not start on both?
Re-posting this from the other Fish Farm thread just in case it was missed by anyone involved in these conversations.
Well, glad to see my goodwill post took all of a couple of hours to go by the wayside! Still haven't turned me into the Grinch yet...but we're trying! I'll try once again to lay it out for everybody so we don't have to be nasty at this most festive time of year.
This post:
"(1 fish is too many in my opinion)
So I take it you don't sports fish?"
Lead to this response:
"Yep I do. My sport fishing has zero to do with how many fish, fish farms kill. I don’t throw garbage in the ocean and I expect industry that does to take responsibility for it. Got a problem with that? Tough crap."
So, as has been stated here before, ALL of you are more than welcome to state your opinion, post studies and facts and be part of the discussion provided it is done respectfully, doesn't lead to fights, stays on topic and doesn't contravene our posting guidelines.
From our posting guidelines/rules:
"Do not make posts that are personal in nature, stir the pot, or provoke another member in such a way that the post serves no purpose but to cause an argument and is irrelevant to the the thread topic."
Now, too be clear, this is nothing personal against either of the members that posted these examples above, I am merely pointing out why we do not want these exchanges to start, as it inevitably leads to problems. And, before I hear from any of you, either privately or in a post somewhere on the forum, about how we "choose sides" based on our personal feelings, I will remind you that members from both sides of this debate have been reprimanded and banned from further participation because they couldn't master the one thing required of them...to follow the expectations of proper behaviour and the posting guidelines of the forum. For those who are into keeping score at home, there are more people who have found themselves on the wrong side of discipline issues on the "anti side" of this debate than vice versa. The only personal issue I have with any of this is how annoying it becomes to have to waste my time dealing with it over and over again.
One last thing to consider, if you feel like you are not being treated fairly here, you have the right and freedom to not participate. If you choose to stick around and continue posting simply remember to follow the guidelines expected and we'll have no problems. This is the third time in the past five days we have had to intervene and remind everyone to avoid posting if it is going to require our intervention. This will be the last warning on the subject, so the next one to post something that is taunting, personal in nature or likely to cause a fight will be gone.
Rant over.
Merry Christmas!
Well, glad to see my goodwill post took all of a couple of hours to go by the wayside! Still haven't turned me into the Grinch yet...but we're trying! I'll try once again to lay it out for everybody so we don't have to be nasty at this most festive time of year.
This post:
"(1 fish is too many in my opinion)
So I take it you don't sports fish?"
Lead to this response:
"Yep I do. My sport fishing has zero to do with how many fish, fish farms kill. I don’t throw garbage in the ocean and I expect industry that does to take responsibility for it. Got a problem with that? Tough crap."
So, as has been stated here before, ALL of you are more than welcome to state your opinion, post studies and facts and be part of the discussion provided it is done respectfully, doesn't lead to fights, stays on topic and doesn't contravene our posting guidelines.
From our posting guidelines/rules:
"Do not make posts that are personal in nature, stir the pot, or provoke another member in such a way that the post serves no purpose but to cause an argument and is irrelevant to the the thread topic."
Now, too be clear, this is nothing personal against either of the members that posted these examples above, I am merely pointing out why we do not want these exchanges to start, as it inevitably leads to problems. And, before I hear from any of you, either privately or in a post somewhere on the forum, about how we "choose sides" based on our personal feelings, I will remind you that members from both sides of this debate have been reprimanded and banned from further participation because they couldn't master the one thing required of them...to follow the expectations of proper behaviour and the posting guidelines of the forum. For those who are into keeping score at home, there are more people who have found themselves on the wrong side of discipline issues on the "anti side" of this debate than vice versa. The only personal issue I have with any of this is how annoying it becomes to have to waste my time dealing with it over and over again.
One last thing to consider, if you feel like you are not being treated fairly here, you have the right and freedom to not participate. If you choose to stick around and continue posting simply remember to follow the guidelines expected and we'll have no problems. This is the third time in the past five days we have had to intervene and remind everyone to avoid posting if it is going to require our intervention. This will be the last warning on the subject, so the next one to post something that is taunting, personal in nature or likely to cause a fight will be gone.
Rant over.
Merry Christmas!
AA, I think the post above by Admin is telling you to let off on squirrel comments. I have been asked to settle my rhetoric down and am taking heed, hopefully, you as a valued member to this debate can find a way to respectfully do the same.
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