New Study highlights 34% loss in wild salmon numbers from Sea Lice

jkchambers

Statement by Inland Fisheries Ireland

New Study highlights 34% loss in wild salmon numbers from Sea Lice

Errors identified which undermine Galway Salmon Farm EIS



Inland Fisheries Ireland notes the findings of a new international scientific paper which identifies fundamental flaws in the methodology and findings of a study (Jackson et al), elements of which have formed the basis of an EIS submitted in support of the proposed Galway Bay Salmon Farm.

The new paper demonstrates that the impact of sea lice on wild salmon causes a much higher loss (34%) of those returning to rivers in the west of Ireland, than the 1% loss suggested heretofore in the Jackson paper. The new study entitled “Comment on Jackson et al. "Impact of Lepeophtheirus salmonis infestations on migrating Atlantic salmon, Salmo salar L., smolts at eight locations in Ireland with an analysis of lice-induced marine mortality" is published by Krkošek, et al. (2013) in The Journal of Fish Diseases. It points out fundamental methodological errors made by Jackson et al. (2013). Following a re-analysis of the same data, it shows that it incorrectly concluded that sea lice play a minor, perhaps even negligible, role in salmon survival and that this finding emerged following three fundamental methodological errors.

This new paper conducts a re-analysis of the data with the findings departing substantially from those reported and interpreted by Jackson et al. (2013), and in previous publications that drew on some of the same data (Jackson, et al. 2011a; 2011b). Whereas Jackson et al. 2013 assert that sea lice cause 1% of mortality in Atlantic salmon, the correct estimate is actually a one third loss (34%) of overall returned stocks.

The new paper gives the example that if, in the absence of parasites, final adult salmon recruitment is 6% of smolt production, then the effect of parasite mortality reduces that recruitment to 4%. According to interpretations used by Jackson et al. (2013), that is a change of 2%. However, the overall effect is that it reduces the abundance of adult salmon returning to a river from, say, 6,000 down to 4,000; this 1/3 loss of salmon returns could have significant conservation or fishery implications. Krkošek, et al. 2013 emphasise that their purpose is not to downplay factors other than parasites that may also have a large influence on marine survival of Atlantic salmon. They do however highlight that parasites can and, in this case, clearly do have a large effect on fisheries recruitment, irrespective of apparent changes in overall marine mortality over time, and with important implications for the management and conservation of wild salmon stocks.

Two of the publications that utilise some of the same data (Jackson et al. 2011a & 2011b), and which contain the methodological errors reported above, have been referred to in the Environmental Impact Statement submitted by BIM in their proposal for a deep sea fish farm in Galway bay. In support of the contention that sea lice do not negatively impact on out migrating salmon smolts, the Marine Institute studies by Jackson et al. 2011a & 2011b are quoted as concluding that the infestation of outwardly migrating salmon smolts with sea lice was only a minor component of the overall marine mortality in the stocks studied. This contention may now be questioned by the re-analysis undertaken in this new paper by Krkošek, et al. 2013.

This paper concurs with previously published international research (Krkosek et al, 2012 & Gargan et al, 2012) which indicates that sea lice emanating from aquaculture facilities can cause significant mortality to Atlantic salmon. IFI welcomes the clarification in this new paper regarding the potential negative impact of sea lice emanating from marine salmon farms and looks forward to ensuring effective sea lice management to reduce or eliminate this impact. In this context, the location of salmon farms in relation to salmon rivers and the control of sea lice prior to and during juvenile salmon migration to their high seas feeding ground is critical if wild salmon stocks are not to be impacted. The development of resistance to chemical treatment of sea lice and other fish husbandry problems, such as pancreas disease and amoebic gill disease, are likely to make effective sea lice control even more difficult in future years.

IFI is supportive of the development of a sustainable aquaculture industry and welcome all advances in research that will underpin the sustainability of this industry and safeguard wild salmon and sea trout stocks into the future.

ENDS...

Zzippy

Up to now, BIM have dismissed all the scientific research that finds negative impacts of seas lice from salmon farms on wild salmon. They have relied on the research of Jackson, a scientist at the Marine Institute - calling his work "definitive" and using it to claim a negligible impact. They have used this "negligible impact" quote over and over when trying to justify the expansion of salmon farming, including the mega-farm proposed for Galway Bay.
This research has now been totally discredited, and the results shown to have been wrong by stating the impact was 30 times less than the actual impact.

BIM now have no evidence to show that sea lice have a small impact on wild stocks - the overwhelming evidence in scientific journals is that sea lice from salmon farms have a very large impact.

This kind of critique of a paper is very rare, and it is essentially an admission by the journal that the original research was flawed. I believe the new paper was reviewed by the same independent reviewers that approved the first paper, so there can be no allegation of bias. Having your work totally discredited in this manner is highly embarrassing for a scientist, and is an indictment of failings within the Marine Institute - certain staff are either biased or incompetent. The Marine Institute are being used by BIM, and it is not helping their reputation in any way. Time for the senior management in the MI to stand up and say "enough".

paddy147

And now theres planning objections to the new Salmon farms that are to be built in Galway Bay.

Zzippy

paddy147 wrote: »

And now theres planning objections to the new Salmon farms that are to be built in Galway Bay.

Got a link to that?

paddy147

Zzippy wrote: »

Got a link to that?

I was reading it in yesterdays Irish Daily Mail...I will take a pic of the article later on,when Im down in my girlfriends parents house.:)

J. Ramone

jkchambers wrote: »

The new paper gives the example that if, in the absence of parasites, final adult salmon recruitment is 6% of smolt production, then the effect of parasite mortality reduces that recruitment to 4%. According to interpretations used by Jackson et al. (2013), that is a change of 2%. However, the overall effect is that it reduces the abundance of adult salmon returning to a river from, say, 6,000 down to 4,000; this 1/3 loss of salmon returns could have significant conservation or fishery implications.

So it appears the brains of the Marine Institute decided that mortality caused at smolt stage should be calculated by dividing the reduction in numbers returning (compared to the treated control group) by the smolt sample size instead of dividing it by the numbers returning in the control group.

When I first started reading this I was assuming the error related to some complex formula. It's almost unbelievable that a scientist could make such a fundamental cock up. A primary school child would see the error of the deduction.

Questions must be asked!

J. Ramone

Oh dear!

They continue to misinform;

http://www.marine.ie/home/services/operational/sealice/

Third paragraph down, lets see how long they take to remove or correct.

_Puma_

The damage limitation begins... One look at the author of this piece and you know the direction the article will take. She mentions one other obscure paper from Norway that has a low percentage of mortalities, albeit from a completely different scenario while ignoring multiple papers from experts in sea lice research from the Royal Institute that agrees with the 30-40% figure.

The marine Institutes response

The institute said that “in the normal course of events, when one scientific publication draws a contrary view or offers a critique of a published scientific paper, it would be for the author(s) of the original paper to consider, in due course, a response through the peer reviewed scientific literature."

In other words they need to buy some time. I am convinced Coveney will be approving the application in the next couple of days/weeks as BIM/MI are now under the spotlight. I really think it is time to up the ante against BIM and Minister Coveney and to start highlighting the impacts these farms will have, in the public arena through public Information evenings or otherwise, not only from Sea lice but from Diseases that are now becoming rampant in farms in Scotland and the complete lack of investigation done into the area by BIM. Also the farce that is the regulation of the farms in this country. Another push on politicians while highlighting the agencies that have now come out against the plan, and the questionable intentions of the MI's aquaculture department.

J. Ramone

On a highly technical issue they would have a point, there should be due process. In this instance, the conclusion of their research is grossly at odds with the data analysis presented.

The appropriate response from the MI would be to immediately withdraw their support of the report finding.