Respected UBC Professor Carl Walters advocates for seal and sea lion cull

[california]

While Walters has supported an experiment to see if culls will improve salmon runs, Dr Andrew Trites who has been consistent in communicating that fishing bans will not work in saving SRKW is also strongly opposed to the proposed 50% cull of pinnipeds by this group. He states they are already in balance, harbour seal populations have been stable for 20 years, being kept in check by transient orcas. He stated he could see future headlines shifting from SRKW to "BC orcas starving due to seal kills to feed China" if this group were to kill as many as they propose. Two separate studies from last weeks symposium at UBC showed seal diets in BC are mainly hake and herring, including one study that looked at estuary seals vs non estuary seals.

 

[Deewar25]

While Walters has supported an experiment to see if culls will improve salmon runs, Dr Andrew Trites who has been consistent in communicating that fishing bans will not work in saving SRKW is also strongly opposed to the proposed 50% cull of pinnipeds by this group. He states they are already in balance, harbour seal populations have been stable for 20 years, being kept in check by transient orcas. He stated he could see future headlines shifting from SRKW to "BC orcas starving due to seal kills to feed China" if this group were to kill as many as they propose. Two separate studies from last weeks symposium at UBC showed seal diets in BC are mainly hake and herring, including one study that looked at estuary seals vs non estuary seals.

That is why the typical NGO message stinks up here - I find it amusing that they disregard all american studies (in Pac NW mind you) as fake news. Serious problem - they will always harp the diet thing and sure, they are correct 'mainly'....but its that month or two in the spring that are doing the damage to the tune of 500 million lbs of chinook (of course another # they refuse to acknowledge because apparently US scientists and biologists don't know what they are talking about). This is huge issue, and since Pac NW is more important for SRKW, I think the sea lion consumption issue down there for returning spawners is a pretty damn big deal as well (believe I read 50% of returning fish these days for a few of the rivers but I'd have to dig around and locate that again).

No question though 50% cull is ridiculous and wreckless and the wrong damn message - focus solely on the problem seals in rivers/estuaries, and yep, wouldn't hurt to shut down the herring fishery while they are at it to give the seals something better to do, but our government sucks donkey balls on that topic!

 

[searun]

While Walters has supported an experiment to see if culls will improve salmon runs, Dr Andrew Trites who has been consistent in communicating that fishing bans will not work in saving SRKW is also strongly opposed to the proposed 50% cull of pinnipeds by this group. He states they are already in balance, harbour seal populations have been stable for 20 years, being kept in check by transient orcas. He stated he could see future headlines shifting from SRKW to "BC orcas starving due to seal kills to feed China" if this group were to kill as many as they propose. Two separate studies from last weeks symposium at UBC showed seal diets in BC are mainly hake and herring, including one study that looked at estuary seals vs non estuary seals.

I would say however, that there is growing agreement within the scientific community that seal predation of out-migrant smolts by specific harbour seals that have learned how to exploit them, and removing those animals is an acceptable method of dealing the Chinook and Steelhead problem. So no scientist, including Carl Walters, is saying a full cull is acceptable. Dr. Trites has said many times the best approach is carefully constructed, very specific removals of problem animals as specific high predation sites. Usually estuaries and smolt migration routes. There is also evidence that seals target larger smolts, so the smaller S-0 Chinook aren't targeted as much when they first emerge from the estuary, whereas the larger S-1 Stream Type Chinook are. Starting to see patterns where the S-0 Ocean Type like Harrison are fairing better than the Stream-Type Upper Fraser Fish for example. However, as the Ocean-Type Chinook grow through the summer they become prey for seals...that is because they tend to hang around near shore areas making them a prey source later in the summer, whereas the Stream-Type Chinook that emerge as larger smolts are targeted as they leave the estuary. So we may need to adopt different strategies...one for specific times where S-1 smolts leave estuaries in the spring, and another later in the summer as the S-0 smolts grow to a size where they are now favoured prey in the inshore waters. Its complicated and there is no easy solution.

 

[california]

Serious problem - they will always harp the diet thing and sure, they are correct 'mainly'....but its that month or two in the spring that are doing the damage to the tune of 500 million lbs of chinook

The study outlined in the Cowichan sampled at different times of the year. In the spring the estuary seals had about 3.5% of their diet as salmon, while non estuary seals it was about 1.5%. The seal diet of salmon was highest in the fall at about 20% , mainly consisting of chum salmon adults. Its an interesting study, and does fit with the high returns of chinook to the Cowichan in recent years. Despite a lot of pinnipeds in the area the chinook run is doing well. Interestingly another study found Herons to be a major predator of Cowichan smolts, consuming about 3% of the smolts released. They found hundreds of tags under the heron nests.

I think the sea lion consumption issue down there for returning spawners is a pretty damn big deal as well (believe I read 50% of returning fish these days for a few of the rivers but I'd have to dig around and locate that again).

Really no question places like the Ballard locks and Bonneville dam are places the sea lions decimate returning runs. I think there was legislation to allow larger kills of sea lions of up to 10% of the Columbia population, but I don't know if it has ever made it in to law.

No question though 50% cull is ridiculous and wreckless and the wrong damn message - focus solely on the problem seals in rivers/estuaries, and yep, wouldn't hurt to shut down the herring fishery while they are at it to give the seals something better to do, but our government sucks donkey balls on that topic!

Agreed!

 

[wildmanyeah]

Really no question places like the Ballard locks and Bonneville dam are places the sea lions decimate returning runs. I think there was legislation to allow larger kills of sea lions of up to 10% of the Columbia population, but I don't know if it has ever made it in to law.

It stalled right now in the senate, passed the house.

 

[agentaqua]

The Standing Senate Committee on Fisheries and Oceans- Bill S-208, An Act respecting National Seal Products Day:
https://sencanada.ca/en/Content/Sen/Committee/421/POFO/02ev-52417-e

 

[saltydawg]

Sea Lion cull is already taking place without our help. Yesterday off Sheringham. 15 CA Transients versus two sealions.

 

[wildmanyeah]

I think there was legislation to allow larger kills of sea lions of up to 10% of the Columbia population, but I don't know if it has ever made it in to law.

COLUMBIA SEA LION BILL PASSED BY US SENATE

http://nwsportsmanmag.com/columbia-sea-lion-bill-passed-by-us-senate/

 

[Stizzla]

I’m hearing how much seals eat hake and save our salmon. I’m interested in learning more... let’s open up the stomachs of 10,000 seals and see how many are in their stomachs. You know, for science!

 

[wayne marwood]

Me and my dad got a very good plan that will make ever one happy and will work very well,shoot the sea lions put them on a airplane fly them up north for the polar bears so if they did that the bear people up there would be happy ,more fish for the wales and fishermen

 

[Deewar25]

I’m hearing how much seals eat hake and save our salmon. I’m interested in learning more... let’s open up the stomachs of 10,000 seals and see how many are in their stomachs. You know, for science!

tongue in cheek aside, I'm actually curious on their argument - this is the one area I have not found a single bit of truth to their statement that hake are heavy consumers of smolt (which to me can justify their 'balance' argument) - I can only find three studies - one doesn't even mention salmon, another has salmon barely even showing up in their bellies during a 3 year study, another off probably swiftsure also has zero mention (of course perhaps since smolt aren't there to be found)

In 1196 adult Pacific hake (Merluccius productus) stomachs from off the British Columbia coast euphausiids occurred in 94%; Pacific sandlance (Ammodytes hexapterus) in 26%; Pacific herring (Clupea harengus pallasii) and eulachon (Thaleichthys pacificus) each 5%; and lanternfish, young rockfish, northern anchovy (Engraulis mordax), and pandalid shrimp each in 3% or less. Fish, particularly herring, were of greater importance in the diet of larger hake. The extent of stomach fullness and the stage of digestion of stomach contents were similar for all sizes of hake taken in daylight tows. The presence of fresh to near-fresh organisms in only 9% of the stomachs, coupled with large numbers (52%) of empty to near-empty stomachs, indicated low feeding activity during daylight hours.

https://ir.library.oregonstate.edu/downloads/3f462590s
calcofi.org/publications/calcofireports/v38/Vol_38_Buckley___Livingston.pdf
So I don't get it - I almost think some study years ago was actually referring to mackerel and they have just hung on to that confusion ever since! Alternatively, perhaps there was one study in a location that had a close deep trough (say off Englishman) and it was shown to be a problem there. That's only thing logical, but since they run in very deep water and only surface feed at night, perhaps most locations don't have issues and therefore never showed up in studies.

 

[Bugs]

The hake question is a difficult one to answer. Full disclosure, I am not a widespread seal cull proponent, but that said, I do think that the strong assertion that hake are important smolt predators is not backed up by the literature. The challenge is illustrated by a study that specifically focused on this question in the Columbia plume. (available here https://ir.library.oregonstate.edu/downloads/3f462590s)

The authors looked at over 5000 hake stomachs over 7 years and found only 5 chinook salmon smolts.... nevertheless, based on this result hake were still estimated to be eating 700000+ Chinook per month just in the limited study area which they were investigating. The issue is that the population size of hake is so huge that even a small diet percentage could be quite a few smolts.. This is a basic problem with estimating ecological roles of very abundant species... So basically the authors concluded that they did not find evidence that hake were an important predator, but they could not rule it out... Anyway, the take home message for me is that it is wrong to interpret this as saying that they are an important predator of salmon. I am not aware of other literature that demonstrates this.

 

[searun]

Your on-line research may not be complete - I have to admit I haven't dug into the Hake predation issue and have taken researcher reference to it as scientifically established fact. I wouldn't however dismiss the Hake connection off hand, as their prey choices per your initial findings of what was easily available on the internet, shows they will target very similar prey to Chinook and Coho smolts. So it is a very logical approach to make the connection that Hake would, if given opportunity, prey upon them.

So I believe the core message that we hear from Dr. Trites and others is we have to be very careful not to chase the shinny penny here. There is more we don't know than we do. Careful measured plans are better than all out assaults on whom we perceive to be the culprits. There could be some bad outcomes from chasing the penny.

I also believe there may be alternatives to removing harbour seals. If we can better understand where/when/who are preying upon the different out-migrating Chinook (Ocean-type vs Stream-type) we might be able to design non-lethal prey avoidance measures that get the most susceptible chinook smolts (large ones) around the prey traps. The research indicates that harbour seals have a preference for larger smolts. They ignore the smaller Ocean-type chinook, likely because they do not represent enough energy intake for the energy output to chase them. The more we understand, the more precise our measures to protect Chinook can be.

 

[Deewar25]

The authors looked at over 5000 hake stomachs over 7 years and found only 5 chinook salmon smolts.... nevertheless, based on this result hake were still estimated to be eating 700000+ Chinook per month just in the limited study area which they were investigating. The issue is that the population size of hake is so huge that even a small diet percentage could be quite a few smolts.. This is a basic problem with estimating ecological roles of very abundant species... So basically the authors concluded that they did not find evidence that hake were an important predator, but they could not rule it out... Anyway, the take home message for me is that it is wrong to interpret this as saying that they are an important predator of salmon. I am not aware of other literature that demonstrates this.

hmm, yeah, pretty much the same way DFO screwed Victoria over the 5-2's after what, 2 coded wire tags were determined to come from our waters?

I really believe hake is a very localized concern - after all, their average depth is waters below 500 feet - seems unless these areas are close to shoreline, they are not travelling long distances for smolt snacks every evening. Actually, would be really interested in what they determine to be 'shallower depths' for feeding.

 

[wildmanyeah]

Just wonder where this robust/abundant pacific hake fishery is that I am missing out on?

 

[searun]

Pacific Hake are found in SOG, and do indeed come to surface areas (particularly at night) to feed. They are also found in shallower depths. Lots of stuff online regarding their life cycle and feeding habits. Another predator species is Black Cod or Sable Fish, which are also found inshore particularly as juveniles. There were tonnes of Sable Fish in the past few years off the West Coast of VI. Incredible numbers of growing fish on La Perouse too.

 

[Cuba Libre]

Pacific Hake are found in SOG, and do indeed come to surface areas (particularly at night) to feed. They are also found in shallower depths. Lots of stuff online regarding their life cycle and feeding habits. Another predator species is Black Cod or Sable Fish, which are also found inshore particularly as juveniles. There were tonnes of Sable Fish in the past few years off the West Coast of VI. Incredible numbers of growing fish on La Perouse too.

Recently there have been up to 4 midwater trawlers working for hake off Bates Beach in Area 14 just north of Comox. No idea what the by-catch is from this fishery.

 

[littlechucky]

Recently there have been up to 4 midwater trawlers working for hake off Bates Beach in Area 14 just north of Comox. No idea what the by-catch is from this fishery.

Undersized springs.

 

[Cuba Libre]

Would seem logical-- but mid-water trawling is one of the commercial fisheries that I dont have experience in. Are there any BC statistics available ( not the AK pollack /chinook info ) ?

 

[searun]

I had same question. My neighbour owns a few mid-water boats. He tells me almost zero Chinook in their nets, so a clean fishery.