Wild salmon stocks 'wiped out' by sea lice

Huge stocks of the iconic wild Atlantic salmon are being wiped out by sea lice from fish farms around the coast.

The wild salmon returning to Irish rivers to spawn are being infested with sea lice, an official report has found.

Some of the fish farms may have to close due to the high mortality rate, according to the international two-year investigation involving the State's Inland Fisheries Ireland authority and top scientists from Ireland and abroad.

On average, 39pc of deaths among wild salmon are attributable to sea lice in areas with salmon farming, the report concludes.

The mortality results may cause the closure of some fisheries when wild salmon numbers are below conservation levels, the report warns.

And there could be serious implications for small populations of wild salmon in small rivers, it adds.

The salmon aquaculture industry is obliged to keep sea lice levels below that needed to protect wild salmon from being infested and dying.

http://www.independent.ie/national-news/wild-salmon-stocks-wiped-out-by-sea-lice-3295392.html

Whats killing the other 61%. Does not seem to be mentioned in the report.

Caz

Whats killing the other 61%. Does not seem to be mentioned in the report.

Caz

Salmon, both in the wild state and in fish farms, are vulnerable to bacterial and viral diseases, and also to infestation by parasites, particularly sea lice.

A common bacterial disease is Furunculosis. The furuncles or boils, which are usually fatal, are most likely to appear in wild fish in warmer months when river levels are low and fish collect in pools while waiting for more water to allow their upstream journey to continue. It has been controlled in salmon farms by vaccination.

Ulcerative Dermal Necrosis (UDN) was rife among wild fish in the late 1960s and early 1970s. Although the causative organism has never been identified, it was almost certainly a virus. It showed itself first in the appearance of small bleached areas on the head, back and tail, which were then covered in a slimy bluish-grey growth. The affected areas were vulnerable to ulceration and infection by fungus.

Infectious Salmon Anaemia (ISA) is another viral disease to which wild fish are vulnerable; it has been endemic for some years in salmon farms in Norway, and was first detected in a number of Scottish farm sites in 1998.

Sea Lice, which can only survive in salt water, are naturally occurring parasites whose presence in small numbers indicates that a salmon in the river is fresh from sea. However, they multiply exceedingly when large numbers of farmed salmon are concentrated in sea cages, and can infest wild salmon smolts encountering them in inshore waters during their seaward migration, with highly damaging results. Sea trout smolts and adults are even more seriously affected because, unlike salmon, they spend much of their life at sea close inshore.

no doubt they will come up with some chemical to add to there feed and still call them organic same way they colour them

A repost but still related to this topic . http://www.fisheriesireland.ie/Notices/ ... y-bay.html

Whats killing the other 61%. Does not seem to be mentioned in the report.

Caz

Predation, disease, commercial fishing are all factors. In the past, marine mortality was about 80-90% of smolts going to sea, now its 90-98% in most years. While its imposible to quantify what has changed in the marine environment, this paper analysed 24 separate studies from Ireland and Norway, and the statistical analysis was able to isolate the mortality caused by sea lice at 39%.

This paper was published in a very prestigious journal, with rigorous peer review, and the main author (Krkosek)has also published similar research in Science, possibly the most prestigious scientific journal in the world. Yet BIM aquaculture development manager Donal Maguire feels qualified enough to discount this research and maintain that sea lice-caused mortality is more like 1%, based on a paper by Dave Jackson of the Marine Institute. Interestingly, Jackson's data was used in the analysis by Krkosek - he could only use the data presented in Jackson's paper, not the raw data requested, as either Jackson or the Marine Institute refused to provide this, even when requested under the Freedom of Information Act! Something to hide???

as a salmon farm employee of 27 years let me dispell some of the dross that is sometimes presented as fact by the press and some other "authorities" on the subject.
all salmon farms do their utmost to eradicate sea lice on our fish as a lice infestation can cause a 30% reduction in feeding and the introduction of infections caused by the lice.
in the critical spring period when salmon and sea trout smolts go to sea all farms are inspected on a 2 week basis to count the number of lice on the fish.the permitted numbers of oviderous females per fish is .5 per fish.if this number is exceeded thn the marine institute will tell the farm to do a treatmtnt.
the most widely used treatment at the moment is hydrogen peroxide, this is a oxidising agent which literaly lifts the lice off the fish whilst the peroxide itself bio degrades in 20 minutes in sea water.
salmon smolt when they migrate to sea do not hang around the bays and do in fact move out to sea at a very fast rate, a smolt that was micro tagged in the screeb fishery in connemara was recovered in a mackerel trawl off the mull of kintyre 8 days later.
in conclusion , salmon farms do their utmost to rid their fish of lice as it causes them large financial costs, they have a legal obligation to do so ,they also have an envoirnmental obligation.
lastly, there are no organicaly certified in feed treatments for sea lice treatment,but you will have to check with the 3 organic certification authorities that certify the fish that we produce to verify this.

salmon smolt when they migrate to sea do not hang around the bays and do in fact move out to sea at a very fast rate,

How about Sea Trout?

Hydrogen Peroxide? You think it's ok to pour bleach into the environment?

as a salmon farm employee of 27 years let me dispell some of the dross that is sometimes presented as fact by the press and some other "authorities" on the subject.
all salmon farms do their utmost to eradicate sea lice on our fish as a lice infestation can cause a 30% reduction in feeding and the introduction of infections caused by the lice.
in the critical spring period when salmon and sea trout smolts go to sea all farms are inspected on a 2 week basis to count the number of lice on the fish.the permitted numbers of oviderous females per fish is .5 per fish.if this number is exceeded thn the marine institute will tell the farm to do a treatmtnt.
the most widely used treatment at the moment is hydrogen peroxide, this is a oxidising agent which literaly lifts the lice off the fish whilst the peroxide itself bio degrades in 20 minutes in sea water.
salmon smolt when they migrate to sea do not hang around the bays and do in fact move out to sea at a very fast rate, a smolt that was micro tagged in the screeb fishery in connemara was recovered in a mackerel trawl off the mull of kintyre 8 days later.
in conclusion , salmon farms do their utmost to rid their fish of lice as it causes them large financial costs, they have a legal obligation to do so ,they also have an envoirnmental obligation.
lastly, there are no organicaly certified in feed treatments for sea lice treatment,but you will have to check with the 3 organic certification authorities that certify the fish that we produce to verify this.

Hi Joyster
I don't think anyone is disputing that salmon farmers do their best to control lice - its in their own best interests after all. But the research is showing that salmon farms, even well-managed ones, are a reservoir of lice larvae that do infest wild salmonids - that don't have the benefit of regular treatments with hydrogen peroxide, or any other chemical treatment.

The paper in question was a comprehensive review of 24 studies where batches of smolts were treated with Slice prior to release, and released with control (non-treated groups). There was a very sophisticated statistical analysis done and the very large data set available means the results are more reliable than smaller studies. The study found a 39% mortality in wild salmon caused by sea lice. This study doesn't say that all those sea lice came from fish farms, but it does suggest it as a probable cause. Many other papers have been published that do link salmon farms with lice-related mortality and population decline in nearby wild salmonid populations.
In short, anyone who maintains that salmon farming does not cause mortality in wild salmonids because of lice either a) cannot read and interpret scientific literature competently or b) does not want to accept fact. I have to include several employees of the Marine Institute and BIM in this group. I'm afraid scientific integrity and principles go out the window with some people when aquaculture is mentioned.

Another recent study found that Corrib smolts take an average of 5 days to leave Galway Bay. The same trawl survey found smolts from north Mayo rivers in Galway Bay! Clearly there is a lot we don't know about smolt migration, if fish are moving up and down the coast like this.

Salmon farms will always be a problem, but management regimes can help minimise their impact on wild salmonids. Timing of smolt input, harvesting, treatment and fallowing are all factors. Unfortunately the history of finfish farming in Ireland has not been one of excellence in management - not saying your farm hasn't been, but many farms have been badly run and caused huge problems for local fisheries. This is compounded by lack of proper supervision and enforcement.

I think organic certification allows for a maximum of 2 treatments during the life cycle, is this true? If so, how do farms manage when lice levels are increasing and they have already treated twice?

hi bredan,
i do not disput the fact that salmon farms have an impact on the envoirnment in which they are placed , it is so with any intensive farming enterprise.
what i would have issue with is the findings of various research reports that are produced. the report that you refer to would suggest that 39% of all smolt that go to sea are killed by the effects of lice predation however it does not establish where the source of these lice is , the impression given is that the only source of lice is from salmon farms which of course is not so.
i would be interested if anyone reading this could tell me how many of our coastal fish are carriers of sea lice,i can think of 9 off the top of my head.
the organic certification bodies allow 2 treatments if slice in the production cycle of a single generation of fish, the remainder of treatments are done with hydrogen peroxide and 2 other permitted bath treatments.
tanglerat was asking about the use of hydrogen peroxide, i have no problem using it properly. the treatments we do are either with a very large bag, 90m circum and 2m deep in which the fish are enclosed and the product added fo about 30 mins until the product has bio degraded, or we pump the fish into a well boat and do the treatment within the well.
one fact that is noticable from this thread is the huge lack of knowledge in regard the movements of smolt when they go to sea .

Thanks for the answer, joyster.

Er, how about those Sea Trout I mentioned?

That's just one report Joyster, and like I said it doesn't specify that all lice came from salmon farms, but there is a whole body of literature linking sea lice from salmon farms with declines in wild populations of salmon and sea trout. The fish farming lobby, including BIM, are very quick to hang their hat on one or two pieces of research that find a low impact, while conveniently ignoring the extensive literature that finds a much larger impact. For instance, Donal Maguire in BIM, who wrote the EIS for the proposed salmon farm in Galway Bay, is keen to quote Jackson's paper which found a low mortality, but ignore Gargan, Krkosek and others who find a much higher mortality. You can't have your cake and eat it - if you're going to be scientific you have to look at the whole body of research, and the (large) majority of research on this issue is not complimentary to finfish farming. You will also find that most of the papers which find low mortality are funded by the aquaculture industry, or state agencies with a remit to promote aquaculture, while most of the contradictory research is funded by government, NGOs, academia or European grants. There also tends to be a correlation with quality, with the most prestigious journals publishing papers that find a high mortality, while those finding low mortality are published in less recognised journals, or journals that cater to (and are read by ) the aquaculture industry.

Re sources of lice, there are 2 species which affect salmonids - Caligus and Lepeophtheirus. Caligus is found on a number of hosts, whereas Lepeophtheirus is specific to salmonids. Lepeophtheirus is the species that does most damage, and causes most concern.

The movement of smolts is becoming better known, thanks to research done by the SALSEA Merge project, although more work needs to be done in inshore coastal areas. For instance, nothing is known of the migration route of smolts in Galway Bay, save for a few trawls which found smolts out in the middle of the bay, just inside the islands. But BIM are able to claim that smolts migrate along the north shore... which suits their application for a salmon farm near Inis Oirr as any other route would put smolts in close proximity to salmon cages.



Some references, in case anyone is that interested (nerdy!)...

Krkoŝek M, Ford JS, Morton A, Lele S, Myers RA, Lewis MA. 2007 Declining wild salmon populations in relation to parasites from farm salmon. Science 318, 1772–1775.

Krkoŝek M, Revie CW, Gargan PG, Skilbrei OT, Finstad B, Todd CD. 2012. Impact of parasites on salmon recruitment in the Northeast Atlantic Ocean. Proc. R. Soc. B, 20122359

Ford JS, Myers RA. 2008 A global assessment of salmon aquaculture impacts on wild salmonids. PLoS Biol. 6, e33.

Gargan P, Forde G, Hazon N, Russell DJF, Todd CD. (2012). Evidence for sea lice-induced marine mortality of Atlantic salmon (Salmo salar) in western Ireland from experimental releases of ranched smolts treated with emamectin benzoate. Can. J. Fish. Aquat. Sci. 69, 343–353.

SALSEA; Report on analyses of the relationships between distribution of post smolts with physical and biological variables (D 5.2), http://www.nasco.int/sas/pdf/salsea_doc ... smolts.pdf

hi bradan and tanglerat,
glad to help with any info ,as regards sea trout, they are a coastal living species moving between fresh and salt water on regular basis ,therefore if the eastury that the fish move in contains a salmon farm that does not have a handle on a lice infestation then the chances are that there will be a problem ..... no body can deny that be it th farmer the marine institute or bim!
on another vein not all salmon farms have a lice problem, sound strange? well when smolt are put to sea they do not have any lice, however after 5to 6 weeks the first sign of caligus will appear, however no lep will appear until there is a sign of wild salmonids in the area. therefore, in a new or fallowed site it follows that it is the wild sea fish and salmonids are the hosts of the lice that appear on the farmed fish, obviously if the infestation is not treated at the stage before the lice mature then there is going to be a problem. the farm i work on we try to treat any infestation as soon as lice show on the fish , to this end i do a weekly check on each cage , taking a sample of thirty fish, anestsisingthem and picking whatevr lice are on them with a pair of twesers.
as regards bim, i would be fairly confident that the pope knows more about salmon farming or wild smolt movements than the whole organisation put together.
one word with regard to the marine institute and bim.....agendas!!!!!!

What I don't understand is how come the farms can't be removed from the sea and put on land. Build tanks on the shore, pipe in sea water, grow the fish, and filter, disinfect or sterilise the waste water before discharging it. Seperate completely the farmed fish from the wild fish populations.

Too simple?

i would be fairly confident that the pope knows more about salmon farming or wild smolt movements than the whole organisation put together.

@joyster: Can you provide correspondence to the Vatican, Holy Sea or other trustworthy evidence in order to proof your statement?
If not, please stick to the facts, we're all fed up hearing nonsense, fiction and hearsay at this stage.

What I don't understand is how come the farms can't be removed from the sea and put on land. Build tanks on the shore, pipe in sea water, grow the fish, and filter, disinfect or sterilise the waste water before discharging it. Seperate completely the farmed fish from the wild fish populations.

Too simple?

Too expensive pumping all that water, when you could have a cage in the open sea that gets flushed with clean water and takes away all the waste for free....

i would be fairly confident that the pope knows more about salmon farming or wild smolt movements than the whole organisation put together.

@joyster: Can you provide correspondence to the Vatican, Holy Sea or other trustworthy evidence in order to proof your statement?
If not, please stick to the facts, we're all fed up hearing nonsense, fiction and hearsay at this stage.

Opinion expressed as a figure of speech, not to be taken literally!

apologies if i upset anyone ,as tanglerat said its just a figure of speech!!!!
after spending allweek being tossed about at sea the thought of farming fish onshore in tanks is very appealing, unfortunatly not very practical.

Hey, I wonder if they nicked the idea from me and organised their conference in the last two weeks?

http://www.irishtimes.com/newspaper/ire ... 85850.html

[cathalger]

Whats killing the other 61%. Does not seem to be mentioned in the report.

Caz

The report states that 39% of salmon mortality at sea is attributable to over production of sea lice bred by salmon farms. This is refering to mainly juvenile salmon entering a marine environment which has a completely unnatural density of salmon louse larvae ('nauplii') in the water as a direct result of the practice of salmon farming in the coastal waters where the young fish first live after leaving the river.

These young fish should be entering a marine environment which is almost completely devoid of salmon louse nauplii in the Spring months, but thanks to the presence of permenent salmon louse factories along our shores, 365 days a year thery arent entering louse free waters as nature intended. Dont be mistaken, most of the juvenile casualties are not a result of the young fish encountering high densities of adult lice. Its the high densities of salmon louse nauplii, microscopic free floating larvae released into the water by the brood stock of female lice attached to farmed fish which are the problem. The nauplii attach to the young fish and go through several juvenile stages before they become a mobile adult parasite. Its then they devour the fish and kill many. the wee fish are naturally supposed to have a few lice but the numbers they experience as a result of farmed lice are fatal to them. Sea trout are probably even more vulnerable to them as they are a coastal fish and they dont go to the arctic circle, ie they are always in the firing line, they are always in the coastal zone where the densities of salmon louse larvae are greatest.

The point is a great many juvenile salmon and sea trout are perishing in our waters every single year as a direct result of the practice of salmon farming and we only get to see a tiny number of the near death badly affected fish beacuse the most of them die and are eaten by scavangers out of sight and out of mind.

The other 61% refers to any other way a salmon can die at sea, eg predation, disease and commercial exploitation. The point of sharing the 39% figure of young salmon killed by farm nurtured sea lice is that if the farms werent there then there would be a greater population of wild salmon, its that simple. Sea trout numbers would increase by an even bigger percentage if salmon farming was removed. They were greater in number before salmon farming and they would be greater in number post salmon farming, to suggest otherwise is disingenuous and absurd. Salmon farms should be called salmon louse farms, for every salmon they produce they produce millions upon millions of a different species of animal- salmon lice.

Edit- These plans are afoot right now to massively expand salmon farming in Galway Bay and in Bantry Bay. If it happens then the seas around SW and the West of Ireland will from that day forwrd have a massive unnatural density of microscopic salmon louse larvae, clouds of which juvenile and adult salmon and sea trout will have to swim through and will become infested by. It will be a continual on going hazard for the fish and many thousand will perish as a result before they reach maturity or get to return to freshwater to spawn. Not to mention the tonnes of sewage introduced to the water from the salmon farms and the chemicals used to try to control ther lice.

I would urge anglers have a look at the facebook page which has been opposing the massive expansion of salmon farming especially in Galway Bay called 'The petition to stop the further development of salmon farms in Ireland'. Do the sea and the priceless indigenous salmon and sea trout populations a big favour and tell salmon farming it isnt welcome in Irish waters. Wild fish populations and rural communities are going to make all the sacrifices to make a small number of rich people even richer if this goes ahead. Dont let it.

https://www.facebook.com/groups/1010797 ... p_activity

Last edited by cathalger on Wed Dec 05, 2012 2:27 pm, edited 1 time in total.