Salish sea seals eat 86% of smolts

[california]

I assume you are aware of the exploding population of Seals and Sea Lions on the South Vancouver Island, including in river estuaries. There is no end of scientific evidence supporting this and most of us who fish regularly have had first hand experience of a Seal or Sea Lion snatching a salmon right off our fishing lines, not just once, but often. In some cases on some trips 3 or even 4 out of 4 salmon. You see the brown eyed thieves following your boat!
No one is talking about a random slaughter, just getting these predators back to the level of the past. Losing a salmon to a Seal or Sea Lion was not an issue in the past!!

I don't dispute the population has increased substantially, its well documented and it had to as they were indiscriminately killed for quite some time. During that time it wasn't unusual for fisherman to shoot at killer whales and the live capture program was very harmful to the populations as well as Killer whales were also seem as vermin and competition only a few decades ago. That's why whales and dolphins are included in the same protection measures seals are. Just to be clear populations ARE at past levels that persisted likely for thousands of years. The population levels that persisted for a short period of time in the 20th century due to human activity were an anomaly.

The transient (Biggs) killer whales unlike the SRKW have done very well, close to doubling in number to over 400 animals in the last 25 years as their preferred prey species have rebounded. While in the past they were rarely seen in the Salish sea, its now not uncommon. So if we begin killing off the seals and Sea lions, it will potentially put the Biggs killer whales in similar situation to the SRKW as far as prey goes. They will potentially begin dying too if their prey species are decimated as its the seal and Sea lion population increases that resulted in their population increase. I think the NGOs and environmental groupswill have a pretty powerful argument against removing protected status for a west coast seal kill when the kill has no economic viability, and will potentially harm a larger whale population than the SRKW, considering the attention the SRKW are currently getting. Just something to consider, killing off or manipulating one part of the ecosystem always has consequences on multiple other ones.

 

[agentaqua]

Interesting points you raise, California - do you have data to support these assertions on historic seal and orca population numbers - or are they just that - assumptions? Are transients truly at risk if we knock off problem seals as well?

 

[california]

Interesting points you raise, California - do you have data to support these assertions on historic seal and orca population numbers - or are they just that - assumptions? Are transients truly at risk if we knock off problem seals as well?

DFO has a report on the seal population (not sea lions) population http://www.dfo-mpo.gc.ca/Library/338997.pdf that estimates the BC population back to 1880 before the first kills started, where its was similar to today before the fist kills started on page 6, and also shows the numbers killed by year. As soon as kills stopped, in 1915 and again in 1970 the population starts going up in number.

for Biggs Killer Whales From a NOAA assessment from 2013
" Current Population Trend:
Recent analyses of the inshore west coast transient population indicate that this segment grew rapidly from the mid-1970s to mid-1990s as a result of a combination of high birth rate, survival, as well as greater immigration of animals
into the nearshore study area (DFO 2009). The rapid growth of the west coast transient population in the mid -1970s to mid-1990s coincided with a dramatic increase in the abundance of the whales’ primary prey, harbor seals, in nearshore waters. Population growth began slowing in the mid-1990s and has continued to slow in recent years (DFO 2009)."

My comment on Biggs Killer whales (BKW) was in response to Fogged In saying we needed to get seal populations back to where they were in the past, which I assumed meant the 1960s. That is when populations were 1/10th of now, and seal lions were probably similar. I think that would have a pretty significant impact on BKW populations if we reduced a main prey item by 90%. If we "Knock off" some problem seals problem it would be unlikely to have much effect on populations or BKW though. If we look at the Harp seal situation, there are about 7.5 Million, the east coast hunt kills about 60,00 per year and the population appears stable. So they can probably stand an 8% annual kill rate like the east coast and not see a decline in the population. The population is considered stable now, so all you are probably do killing some is increasing the survival rate of the young ones, and still having a stable population, but it might be beneficial to remove some that have learned behaviours that enable them to effect returning adult salmon disproportionally.

 

[agentaqua]

Thank you for your detailed reply, california. Earlier you wrote:

The transient (Biggs) killer whales unlike the SRKW have done very well, close to doubling in number to over 400 animals in the last 25 years as their preferred prey species have rebounded. While in the past they were rarely seen in the Salish sea, its now not uncommon. So if we begin killing off the seals and Sea lions, it will potentially put the Biggs killer whales in similar situation to the SRKW as far as prey goes. They will potentially begin dying too if their prey species are decimated as its the seal and Sea lion population increases that resulted in their population increase.

Yet in your next post you write:

for Biggs Killer Whales From a NOAA assessment from 2013
" Current Population Trend:
Recent analyses of the inshore west coast transient population indicate that this segment grew rapidly from the mid-1970s to mid-1990s as a result of a combination of high birth rate, survival, as well as greater immigration of animals
into the nearshore study area (DFO 2009). The rapid growth of the west coast transient population in the mid -1970s to mid-1990s coincided with a dramatic increase in the abundance of the whales’ primary prey, harbor seals, in nearshore waters. Population growth began slowing in the mid-1990s and has continued to slow in recent years (DFO 2009)."

and since during that time the harbour seal population has expanded exponentially means that the transients have not been able to hold the seal population in check, and that seal prey population is not limiting the growth of the transients - data which does not support your assertions in your 1st post - #101. Stock trajectories are NEGATIVELY correlated if transient reproduction is slowing over time while seal numbers are expanding.

AND

If we "Knock off" some problem seals problem it would be unlikely to have much effect on populations or BKW though. If we look at the Harp seal situation, there are about 7.5 Million, the east coast hunt kills about 60,00 per year and the population appears stable. So they can probably stand an 8% annual kill rate like the east coast and not see a decline in the population. The population is considered stable now, so all you are probably do killing some is increasing the survival rate of the young ones, and still having a stable population, but it might be beneficial to remove some that have learned behaviours that enable them to effect returning adult salmon disproportionally

Thank you for your honest answers in your second post. As far as I am aware - nobody is seriously advocating for a large-scale, indiscriminate cull - but rather looking at the potential positive impact of a small-scale, focused cull on some problem seals.

 

[OldBlackDog]

AA, they should actually look at what happened on the Puntledge River.
Then they will know that the cull will have to be done annually.

 

[california]

Thank you for your detailed reply, california. Earlier you wrote:

Yet in your next post you write:

and since during that time the harbour seal population has expanded exponentially means that the transients have not been able to hold the seal population in check, and that seal prey population is not limiting the growth of the transients - data which does not support your assertions in your 1st post - #101. Stock trajectories are NEGATIVELY correlated if transient reproduction is slowing over time while seal numbers are expanding.

Maybe your and my interpretation of the graphs in the seal assessment and the quotes from NOAA differ a bit. If you look at the graphs on seal stocks, they increase exponentially for seals from 1970 until about the mid 1990s, then the growth rates slow to more a linear growth and finally a leveling off of the population with slow or minimal growth from about 2010. The NOAA report does not claim Transients have stopped growing just the rate of growth has slowed from the rapid growth of the 1990s, as it has done for the seal and sea lion populations and the timing is roughly the same. Salish sea seal populations which is what many forum members encounter, have continued to increase at a faster rate, but that is only a small part of the BKW range (CA-AK) and one could argue that it may not even be a preferred range given the shipping traffic and whale watch boat harassment they get as soon as they enter the southern Salish sea. That being said the Center for Whale research reported BKW are being sighted more each year in the SS, so maybe they are coming in more often to prey on the increasing seal population.

When I read these forums I mostly see calls for large scale culls, wording like to "get it back to where it was" meaning pre-1970. This I disagree with, and a cull would be useless anyhow. Its estimated the seal population can increase its size by as much as 12% per year. A cull of even 25% would have the seals numbers come back within just a few years, so it would have to be ongoing. The population is thought to be stable now, and from a pragmatic perspective I do agree with focused removal of problem animals impacting returning adult salmon, like they do on the Columbia Bonneville ladder. A man made barrier has unfortunately provided an unnatural opportunity for sea lions to prey on salmon stacked up there. Huge dominant males learn there are salmon there and take control of the spot. The only way to stop them eating returning chinook is to remove them. I believe they are currently trying to decrease the bureaucracy necessary to remove problem animals at the Bonneville damn.

 

[Dave]

This stacking up of seals and sea lions at salmon barricades is not new ... Lewis and Clark reported seeing "vast numbers" of sea lions at Celilo Fall, aka the Dalles or the Narrows, during their exploration of the Columba River in the 180o's.
Pinnipeds are intelligent animals and will congregate wherever food is available. I don't know how many salmon I have seen taken from the Albion test fishery nets by seals but really, this is our fault in supplying an easy source of food.
Unfortunately, just like we kill wolves when they are perceived to take too many of "our" ungulates, some seals most likely will be removed, and like the wolf kill, this cull will have to be continual. I am just not sure if there will be a public appetite to continue the killing though ..

 

[wildmanyeah]

People want to have their cake and eat it too.

You can't expect to get into bed with ENGO's to rid BC of fish farms and then expect these ENGO corporations to shut down their multimillion dollar businesses. They we will be their to block any seal cull or hunt. Any video protestors can get of the hunt/cull/population reduction will bring in millions of dollars of revenue for these ENGO corporations.

Regardless of my own opinion on Seals, as I would like to see a seal reduction. I can see the power of these ENGO's now have over our local, federal governments and the population at large though well planned social media campaigns. The science is not clear on seals just like its not on fish farms. The ENGO's will use that as leverage and even put out their own scientific presentations/papers to show how devastating a seal cull/hunt would be.

ill just leave this here..... https://www.harpseals.org/politics_and_propaganda/dfo_failures.php

 

[agentaqua]

AA, they should actually look at what happened on the Puntledge River.
Then they will know that the cull will have to be done annually.

Her's some other, related studies - the puntledge one is too large to post...