Seems like only yesterday when I was a young boy fishing on lake Michigan with my Grandpa & Dad for Chinook Salmon, many of these giants would reaches sizes in the 30 lb range. This was not uncommon in the early 1980's, Chinook up to 40 pounds were recorded every season on both Lake Michigan and Lake Huron. Massive populations of Alewives gave these Salmon plenty to feed on all year long in these two Great Lakes. These Chinooks thrived in the Great Lakes during this time frame.
Around 2000 Chinook Salmon populations seemed to be declining a bit on the Lake Huron side, maybe we thought it was just a smaller run of fish this year. Chinooks seemed to be skinny & on the small side verses what we were used to. So another season came around and even less fish were around, no one seemed to have an answer as just as many Salmon were being stocked as prior years. This trend continued until finally some answers were being given by scientists, fisherman & our state agencies.
The answer to the declining Salmon fishery on Lk Huron was directly related to the shipping industry that uses the Great Lakes for commerce. The vessels that enter the Great Lakes system from the saltwater were directly dumping ballast water that was collected from water bodies other than the Great Lakes directly into our waters carelessly. This was introducing invasive organisms into a water body that has never seen anything such the likes of this. What has happened since is absolutely horrible.
Organisms such as the zebra & quagga mussel has overtaken Lake Huron-in laymans terms these mussels eat the food that the alewives need for survival more or less. Thus creating an environment void of food for the alewives, this means if the alewives have nothing to eat-they starve to death. This in turn creates a entire crash of the system from the bottom to the top predator (Chinook). Luckily Steelhead, Atlantic Salmon, Pink Salmon, Lake Trout, Brown Trout & Coho are not as reliant upon the Alewife population as the Chinook Salmon. These other Salmonid populations seem to remain strong despite the low numbers of Alewives in Lake Huron, they have a more diverse diet that doesn't purely reply upon baitfish. Atlantic Salmon & the others tend to eat what is available, aquatic insects & other baitfish provide enough food for these species to still thrive.
Since this crash in baitfish populations Michigan DNR has cut back stocking efforts on Lk Huron, no reason to stock a fish that purely relies upon alewife when there are no alewives present. The only stocks of Chinook that happen on Lake Huron are purely for tribal treaty reasons, which is a whole separate issue. Michigan & Canada now rely solely upon natural reproduction for Chinooks in Lake Huron, some of the river systems have astounding rates in natural reproduction which keeps Chinook numbers present.
Michigan DNR biologists figured that this may happen in Lk Michigan in the near future, so they cut stocking efforts of Chinook to try to balance out the predator/prey balance. This was done around 5 years ago & now Chinook numbers are not nearly what they used to be in Lk Michigan. Current research on Lk Michigan on baitfish populations are not good. Steadily declining numbers of alewives, smelt & others are pointing towards the same issue that happened in Lk Huron. This year class of Chinook appeared to be smaller & not as many as usual. I'm not panicking yet as fish were still what I would consider strong in numbers & fishing was good. This is such a frustrating situation that was caused by something our government could have controlled. Its not rocket science either, it is amazing that uncontrolled dumping of ballast water has occurred for so long.
Check out this link to a study on Lk Michigan biomass, it pretty much tells the more scientific story of what I explained above. Hopefully sound management & good decision making by our State agencies will ensure quality fishing for generations to come.
It is amazing to me how quiet people are keeping about this, hoping that it will go away or something. It isn't going away & it seems like not many people are stepping up. The more people who know about this problem the better, tell your legislator about this & that it is of importance to you. It's better to be proactive verses reactive.