A good sized salmon from the recent salmon trip

Let me start this by saying I'm not a scientist, only an interested individual who spends a great deal of time on the water trying to understand and looking into aspects of fishing that really interest me. With that said, I have a pretty good understanding of many of the issues facing the future of the Great Lakes cold water fisheries, particularly king salmon. By now it is no secret that the 2017 Lake Ontario and her tributaries salmon season has been one of the best if not the best season in recent memory, both in numbers of fish and in size of fish captured. And this is not just limited to Lake Ontario, either. All you have to do is look catch rates from the two big salmon producers- Lake Michigan and Lake Ontario- and it is a no brainer. A 42 pound king was caught out of Lake Michigan in August. A 39 pounder was reeled in on Lake O. The Salmon River has seen the largest run of early fish, some of them well over 30 pounds, returning between the first two weeks of September than any season I can remember. On September 8 when we were fishing, there was large numbers of fish all the way up to the Upper Flies Only Zone.

And people are really, really excited by it. For good reason. Last salmon season was a bit of a bust. Lower numbers and low water made it challenging but fish were there. To be sure, I'm excited about the fishing that's going in in Lake Ontario and the tributaries too. But I'm also pretty concerned. The reason I'm concerned is that with all these big salmon around, they're eating a lot of baitfish. Alewives in particular. And the population has taken a really big hit recently. As I write this, the cold winters of 2013-14 and 2014-15 resulted in very few young of the year fish being produced. To be sure the back to back warm winters of 2015-16 and the record warm 2016-17 resulted in high production (especially 16-17), right now the alewife population in Lake O is made up of predominantly year class 1, 2, and 5 fish. And of those, it is the year class 5 that are the ones especially needed to spawn. In fact female alewives don't usually mature until year 4 or 5, though males mature a bit early (usually 3 or 4).

What this means is that there is likely only one year class of sexually mature and productive alewives in Lake O right now. And there are a lot of big, hungry salmon. And those warm winters of 15-16 and 16-17 didn't only help out the alewives. Smolt survival through the first winter in the lakes during that time was likely equally high. I suspect the next couple years will also have good salmon fishing. But the result of this really good salmon fishing means that more fish will be fighting for fewer alewives (the primary food source for kings). Those year 1,2 and 5 classes are the targets of the  salmon. And like I said, there seem to be quite a lot of them around.

So when the foraging for bigger alewives becomes difficult, as will likely occur in the next year or so once the numbers of year 5 alewives continue to drop, you can bet the farm that the salmon will start keying in on the smaller classes even more. The salmon will end up needing to eat more smaller alewives to make up for the lost larger meals. And this starts what in statistics is called a positive feedback system (though only positive in name as it only amplifies the problem). The salmon need to exert more energy to catch and eat more smaller alewives resulting in their need to eat more smaller alewives to make up for the energy lost hunting down and eating the last meal. Sort of a catch 22: by needing to target smaller meals, they will need to eat ever more increasing small meals to replace energy exerted.

Once this occurs, it is very difficult for a population of prey species to replace the individuals that have been eaten, let alone expand a low population to higher numbers. And this appears to be where we are, or will be very soon with Lake O alewives. If any more proof is needed, all you have to do is look at the salmon crash in Lake Huron that really hit in 2004. Until about 2001, salmon numbers and size were stable, but not alewife populations. In fact 2001 was a banner year for size and numbers. Within a few years afterwards, king salmon virtually disappeard from the lake. 

While Lake O is very different that Lake Huron, some things remain similar. Predator and prey populations need to be balanced. If a man made system, such as stocking, is attempting to do so, then it must understand outside influences such as natural reproduction. It has only been in the last five years that wild reproduction of king salmon was really evaluated in Lake O, and the results were startling: lakewide roughly 50% of all kings are naturally reproduced, in the Salmon River that number is more like 75%. With all that natural reproduction going on, is it still necessary to stock that many kings?

While they sure are a blast to catch, are we allowing the kings to eat themselves out of house and home? Nature will find a balance, and if we are not careful, it may be a balance we don't like. One of the first signs will be emaciated adult kings showing up in increasing numbers. It will be sporadic at first- a few here, a few there over the course of a season. Then a more as time goes on, until the problem becomes impossible to ignore any longer. That's the way it went for Lake Huron. Check out some of these pics of starving kings from before the crash:

 

and:

Big heads and tails, but hungry kings. Photos from Michigan DNR.

Those are pics are from back in the early 2000's. I saw a picture that got my attention yesterday:

That's Garrett Brancy from Douglaston Salmon Run holding a fresh run chrome king. All I could think of was how much it reminded me of those hungry Lake Huron salmon. Though hopefully it was simply a fish that really, really sucked at hunting while out in the big, open water, it still makes me nervous.

The Lakes are changing. The water is cleaner. Alewife populations are low all the way through. If given the choice I'd rather fish for fewer, bigger fish than more smaller ones. And the problem with planning for the more smaller ones is it's easy for uncertainties such as hard winters to disrupt a plan. We can all suffer through a bum salmon year if a harsh winter kills more smolts than expected. Does it suck? Of course. But we tighten our belts and make it through.

But a few harsh winters, or maybe even just one, can spell doom for a prey population if there are too many predators around. Maybe we don't even need the harsh winters if there are just way too many mouths to feed. It'd be a shame to see the big kings go. And this current salmon fishing makes me nervous. I hope I'm wrong.

Tight lines guys,

 - D