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[Rodney]

This was livestreamed a couple of days ago and a really informative webinar. You can now watch th replay at:

YouTube: https://youtu.be/Ld9teabSSXs
Facebook Live: https://fb.watch/2h9qF1BuuT

[hammer]

Seal..

[RalphH]

I've watched Bisson's webinar and there is a lot of good information in it. However some of it, in particular the suppositions about what a seal cull could do for IFS recovery struck me at least as a product put together for a customer. Unfortunately many people are taking this information and running with it, even to the point of ignoring Bisson's own cautions about the estimates (which Bisson described as idealized) provided for possible IFS recovery strategies.

Contrary to the impressions given by some on this and other sport fishing websites, there isn't a broad consensus that pinnepeds are responsible for the declines in steelhead, coho and chinook populations or that a cull will halt or reverse their decline or can be conducted with predictable results given the current knowledge base.

Here are a couple of websites and links for further information:

To Kill Seals and Sea Lions? Selected Quotes  and Content from the Technical Workshop Proceedings. May 29-30, 2019. Marine Mammal Research Unit, University of British Columbia, Vancouver, B.C

https://mersociety.wordpress.com/2019/03/26/to-kill-seals-and-sea-lions/

Full text from the same workshop:

 https://mmru.ubc.ca/wp-content/pdfs/Trites%20and%20Rosen%202019%20Pinniped%20Workshop%20Proceedings.pdf

Behind the Blubber. Harbor seals are blamed for chinook and coho salmon declines, but ecosystems are more complicated than some suggest.
Hakai Magazine author Larry Pinn

https://www.hakaimagazine.com/news/behind-the-blubber/?fbclid=IwAR3n-fRWWdSda6u6MNa5LE4tevXQRwX5JHMIjcUXHDgQMvk1BG_Sd7Cun1I

One of the most important points is that evidence indicates that seals in the Strait of Georgia separate into at least 2 feeding groups - those that feed in estuary and river areas; those that feed away from those areas. Not surprisingly the later do not feed on steelhead, coho or chinook or intently on salmon at all. This could mean the studies used to suggest seals may consume 35 to 50% of young coho and chinook are heavily biased by the fact the samples were gathered from estuary zones and then used to project those estimates. Thus those estimates may be significantly exaggerate the effect seals have on the decline of those 3 species.

[CohoJake]

One of the most important points is that evidence indicates that seals in the Strait of Georgia separate into at least 2 feeding groups - those that feed in estuary and river areas; those that feed away from those areas. Not surprisingly the later do not feed on steelhead, coho or chinook or intently on salmon at all. This could mean the studies used to suggest seals may consume 35 to 50% of young coho and chinook are heavily biased by the fact the samples were gathered from estuary zones and then used to project those estimates. Thus those estimates may be significantly exaggerate the effect seals have on the decline of those 3 species.

Indeed, I would certainly want to know where these samples were taken.  I've also wondered if there would be some way of effectively controlling the pinniped population short of outright killing them - i.e. birth control/sterilization darts? Scratch that idea - they live for 25-30 years.  We can't wait that long for a population decrease, but maybe once the population is reduced it could be used to control them?

[Dave]

Good post Ralph, I agree with your assessment regarding the impact seals are having, especially on juvenile salmonids.
Seems to me there may be an easy way to determine what, if any stocks from the upper Fraser chinooks or IFS steelhead, are being consumed by seals is by doing DNA analysis of seal scat.  If samples are too "digested", sacrifice a few in the name of science, lol!

The fact this has not been by now suggests to me perhaps the analysis is not possible, but I find that hard to believe.

[Rodney]

Good post Ralph, I agree with your assessment regarding the impact seals are having, especially on juvenile salmonids.
Seems to me there may be an easy way to determine what, if any stocks from the upper Fraser chinooks or IFS steelhead, are being consumed by seals is by doing DNA analysis of seal scat.  If samples are too "digested", sacrifice a few in the name of science, lol!

The fact this has not been by now suggests to me perhaps the analysis is not possible, but I find that hard to believe.

DNA analysis has been done on Southern resident kill whales to determine the origins of the chinook salmon they are consuming so anything is possible...

[Dave]

I see a great thesis coming up for some bright student 

[Rodney]

Operation Scoop a Poop. I'll film.

[wildmanyeah]

Oh you could just federally protect salmon the same way they have protected seals.

In just 50 years of being federally protected seals have recovered to historic levels. Wonder what would happen if you protected salmon the same way. There population would probably be pretty strong in 50 years with Thoes same protections.

Why protect one and not the other?

my friend backwards if you ask me

[RalphH]

too much money and emotion in salmon, virtually none in seals...as yet.

[DanTfisherman]

I see a fascinating contradiction here.

As of late, fisheries are closed, and anglers cannot even participate in catch and release fisheries, for "every fish counts" and our impact on the fish is too great to risk individual fish dying or being injured.  We do not really know the true impact of angling, and do not have the stats, but we have decided to close the fisheries as a conservation measure, without knowing the success, stats, or potential long term benefits.

Last year, I lost three coho to seals at the mouth of the Vedder.  I can say I watched and know what happened to these fish.  I saw the same happen to fish in the Vedder, Harrison, and Nicolman both on lines of other anglers, as well as without angler influence.

If DFO uses analytical evidence and hypothetical ideas to decides that fish are too valuable, each one counts, so we need to close these fisheries down, would the same rules not also apply to seals and their impact on the fish.  If every fish really does count, and we do not know the true impact, would it not be best in the long term to conduct a cull of some sort?  Hypothetical ideas would suggest culling seals could have the potential for a positive impact and could be carried out in a meaningful way.

We know and understand that a cull of seals in estuaries would have no long term impact on the health and status of the seal population as a whole.  I do know that it is theorized that all mammals develop instincts and evolve to survive over time.  Seals that target salmon in the Fraser are evolving and developing strategies to survive and thrive in this environment.  As they evolve and develop a unique skill set, they will breed and pass on this trait to their offspring, who will also be more apt and conditioned to survive in this environment.  Seal populations in the Fraser system have been increasing, and I would argue the amount of time they remain in the system seems to be longer.  For them to be there and spend longer periods of time in the system must mean a stable food source of some sort is there.  It is interesting to see they seem to be doing better and increasing, as what I would assume the food source would seem to be struggling and dwindling?

I myself had spent a great deal of time advocating against culls in the past.  I still do not like what I am suggesting in this thread.  I do note there are very distinct trajectories taking place in the Fraser.  Salmon stocks do appear to be distressed, decreasing, in decline, and under threat.  Seal populations do not seem to be distressed, are increasing, and not under threat.  Not all the seals in the oceans are exhibiting behaviours of coming into rivers to get an easy meal.  We acknowledge that, at times, while unpopular, problem bears and their offspring once habituated to raiding garbage for food and becoming nuisance bears need to be destroyed.  Why can we not apply the same principles to a small number of the seal population who have potentially become a threat to the Salmon?

Dano

[redside1]

If DFO uses analytical evidence and hypothetical ideas to decides that fish are too valuable, each one counts, so we need to close these fisheries down,

Dano

the true reason why each one counts is DFO is reallocating the fishery from one user group to another to correct past wrongs and move forward with reconciliation. Toss in FSC requirements and there are currently only enough fish left for one user group.
In a recent meeting a DFO employee said "each one counts" when sports fishing went all Silent Bob when asked about the in river gill netting and mortality. Had no response and waited until the subject was changed to speak again. 

[RalphH]

Bob Hooton weighs in on the culpability of seals in the decline of Thompson & Chilcotin Steelhead:

http://steelheadvoices.com/?p=2293

extracts:

The major assumptions inherent in the seal predation problem relate to both outgoing smolts and returning adults. I submit those assumptions are not well founded. Thompson steelhead smolts are undoubtedly few in numbers and certain to be very thinly distributed spatially and temporally during emigration. There is zero evidence in support of popular opinion they are larger than any other food item present at the time and therefore differentially targeted by seals. Remember also, seals are sight feeders. Just finding Thompson steelhead smolts, let alone targeting them, during their emigration season when the Fraser is in freshet and highly turbid is extremely unlikely and definitely not supported by empirical evidence.

Clearly the Coquihalla (a small coastal summer steelhead stream tributary to the Fraser about 160 km inland) has not experienced the same unidirectional trend as the Thompson over the past two decades. Then consider the relative amount and quality of steelhead producing habitat in the former is a tiny fraction of that available in the latter. In fact the Coquihalla was subjected to serious habitat abuse by both highway and pipeline construction. There was also a major slide event between 2014 and 2015 that limited the ability of a large proportion of returning adults to access normal reproductive habitats (light blue in the figure). There is absolutely nothing to suggest smolts from the two systems are different in size, that they emigrate via different routes or at different times or that they pasture in different areas of the Central North Pacific. As returning adults one can only assume they travel the same routes and are exposed to the same commercial fisheries and suite of predators.

The only difference between these two stocks is their immigration timing. Coquihalla fish immigrate at or near the peak of the annual Fraser freshet when water velocities and debris are at seasonal maximum and limit gill net fishing effort. Coquihalla steelhead have not been subjected to anywhere near the same in-river gill net pressure as have their later returning Thompson cousins whose timing mirrors major increases in First Nations gil fisheries primarily targeting hatchery supported chum salmon.

Those who support computer models that point accusing fingers at seals have never acknowledged the Coquihalla contrast. In fact I’m not convinced any of them are even aware of a data set that flies in the face of their models.

all emphasis are mine.

[RalphH]

I am going to add another couple of points here:

Many people are talking as if the current seal population is a recent occurrence - something that has happened in the last few years. Truth is the major part of the seal population increase took place in the 80s and it's current population has been stable for over 20 and perhaps 25 or more years. At various times we have had good returns of chinook, coho and even steelhead in some streams since then. The largest sockeye return on record took place in 2010. If seal and sea lions were soley responsible for the current state of inside salmonid stocks we should  have seen that effect decades ago.

Perhaps much of the current state of 'panic' has been the dramatic decline of sockeye and chinook in the Fraser over the last 5 years and more dramatically the Big Bar Fraser River slide last year. Despite that some stocks such as the South Thompson Chinook have done reasonably well and the 2018 Fraser sockeye return was healthy. The other declines we have seen have happened at the same time as the worst ocean conditions for southern stocks pretty much in recorded history. This is generally true for other low cycles we have seen since the early 90s. Ocean conditions for southern BC have gone from near ideal in the late 70s to the early 80s to pretty much worst on record. Poor ocean conditions mean less food (ie zooplankton) for salmon at sea as well as for forage fish.

I'll also make a point about the use the statistical method of correlation to establish a relationship to seal population growth and salmon decline. Correlation is one of the simplest techniques in statistics and is taught early in any introductory stats course. It calculates a algebraic straight line between a set of point that best matches the points scatter on a graphs. It also calculates coefficients that give an indication how accurately the line fits the points. As has been said it does not establish causality.

Correlation is easily fudged or manipulated. The fewer points the greater likelihood of a high correlation factors. Higher or lower factors can also be obtained or avoided by where the plot starts and ends. It depends what sort of point one wants to make. Putting it simply by starting the calculation where seal numbers are at an historical minimum and ending it at a high while salmon are mostly declining pretty much guarantees high correlation coefficients.