Spring on the Great Lakes

RLLigman

Well-known member
Three of us fished a Great Lakes tributary for steelhead prompted by a call from Kevin to tell me he was seeing near-constant "flashing" males (males flipped on the sides fanning the gravel to make a redd). We actually caught more fish, but two of us sorted fish to only keep hatchery origin fish. This river has some really beautiful scenery as well, courtesy of two waterfalls, one of which serves as the upstream limit. Today's rain will really start pulling fish in. Time to get the boat uncovered and start trolling for spring salmon as the diatom hatch peaks. Smelt numbers are rumored to be up on Superior. T,he "stubby" male posed at a right-angle to the other fish has a broken spine at the caudal peduncle. Kevin supplied the ties to just drop fish along the bank. He said he has never had a fish stolen...
Rods were 9' 8WTs. with a sink tip. Scented beads, egg flies, and #10 black or brown stones and peacock buggers took all the fish.
View attachment Huron+steelhead.jpeg
 
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Looks like a lot of fun fishing. The "stubby" one with a broken spine. Is he a wild fish that you kept because he has a broken spine or was he also a hatchery fish? I am just curious because he is so much prettier than the others. Or is he just "fresher" than the others?
 
Dani, in salmonines (salmon and trout), males arrive prior the females to stake-out their spawning redds and defend them, basically apportioning the existing substrate. Steelhead tend to darken once they enter rivers from the Great Lakes, a physiologic response that minimizes their contrast against the background; converse when they are back out in open water. The brighter lateral red/pink is a secondary sexual characteristic influenced by hormone levels. Look closely at the heads of these fish; they ones with the rounded snouts are hens and the fish with the more pointed snouts are males. Some of the males are developing kypes as well, indicating how close they are to spawning. I kept the broken back male because he was a hatchery fish with an AD clip. The USFWS has been running a Coded Wire Tag program for nearly a decade now assessing movement and seasonal distribution patterns of Great Lakes salmonines, with all AD clipped fish containing a micro tag inserted in their snouts prior release. Each CWT array is recorded by plant site, with USFWS techs. gathering heads and removing the CWTs to record their origin site.. This initially was targeted at chinook and coho for nearly a decade to determine movement, resulting in the documentation of seasonal and annual movement of these species, wild origin and hatchery derived stocks, freely between Lakes Michigan and Huron, something I and several others have been trying to convince the State fishery managers was occurring since 2007. Lake trout, and now steelhead are receiving CWT via a trip through the mass-marking trailer where fish are fed into a hopper, sucked into a tagging chamber that scans the fish several times prior simultaneously inserting the CWT and swinging a razor blade across the base of the adipose fin. Tagged fish are released into another holding hopper where they are visibly inspected to make sure they were marked as well as to verify that they did not invert in the marking chamber (this was designed for Pacific salmon but has been modified to used for other salmonines that are not as deep dorsal-ventrally. Lake trout were the big variant.)

Fish often are swept up from their raceway and dumped out on a barred grid to size sort them, with some fish injured in the process. Often in a three pass raceway system the fish in the third raceway exhibit slower growth due to increases in nitrogenous waste products from fish excretions across their gill membranes, as well as in the excrement. When I took fish culture Harry Westers rotated fish from last to first based on his growth criteria for Michigan's hatchery system.
 
Well, there's my science fix for the day!

Cool info. Do the steelhead compete with the native coaster brookies? Or do they spawn at different times?
Any numbers on how successful their spawning efforts are in recruiting juveniles back into the population?
 
Other than the folks working on the Nipigon River population the general data indicates that coaster brook trout are largely excess production the emigrates from flash basin streams in good production years where YOY fish exceed carrying capacity and end-up in open lake waters. USGS, and MiDNR researchers tagged native brook trout and planted coaster strain fish with small electromagnetic insert transmitters that generated two distinct signals in three streams that discharge into Lake Superior. They laid electromagnetic generating cables in the substrate at the mouths of these streams and recorded annual emigration rates of each brook trout stock. Over the duration of the study native brook trout emigrated to open lake waters at a higher rate seasonally and annually that the coaster strain plant fish, largely negating the genetics driven hypothesis with regard to what makes a brook trout a coaster brook trout. The more abundant food resources (many of the Lake Superior tributaries that contain basins consisting largely of Canadian Shield igneous rock formations also form anchor ice deposits in severe winter weather intervals, diminishing primary and secondary production and productivity.

Niche overlap and degree of annual resource competition among Great Lakes salmonines, stratified by open lake quadrant in Lake Michigan was quite convincingly addressed by Matt Kornis, USFWS researcher at their Green Bay Facility:

(PDF) Spatiotemporal patterns in trophic niche overlap among five salmonines in Lake Michigan, USA (researchgate.net)

Those of us who argued that the MDNR, WDNR, IDNR, and Illinois.DNR managers made a massive mistake when they collectively opted to choose a fifty percent reduction in chinook plants (Option 2) over the option of applying a multispecies plant reduction approach based on bioconversion and consumption efficiency data (Option 4) in spite of each Decision Analysis Model scenario "run" one hundred, one year iterations, yielding a significantly higher probability of generating a great alewife population stock via the muli-species reductions when compared to the single species reduction option. What drove their decision? They would not have to toss fish in the hatchery rearing systems that were species dependent on multi-year rearing cycles.

They saved some hatchery fish.. avoiding having to explai to the politicians why they threw the in a landfill.and nearly crashed the entire open lake population, very nearly destroying a multi-billion dollar fishery!

Pre-dreissenid mussel invasion, spring diatom blooms largely drove the productivity of inshore Great Lakes waters providing high free fatty acid content forage for cladoceran zooplankton as well as the inshore native Gammarid amphipods and their deepwater cousin, Diporeia sp., as well as Mysis diluviana stocks. Post-spawn alewife would move offshore into waters > 150 FOW to feed on Diporeia sp. and Mysis sp. to regain somatic energy stores that they had "tapped" to make gametes Coincidentally, Diporeia sp. and Mysis sp., as well as cladoceran zooplanktors are at their annual peak in proportional free fatty acid concentrations in body tissues in mid-Ju;y. Dreissenid mussel colony filter feeding has markedly impacted bothe the scope and duration of the inshore diatom blooms in the lower Great Lakes that they infest now. In 2007 there were roughly 9 age-classes of alewife within the Lake Michigan stock. Doctor Kornis was able to document, via stable isotope food habit assessment analysis techniques that lake trout stocks that surpassed Pacific salmon stock numbers over the 2007-2009 interval feed preferentially on these adult (3YO and older fish) alewife, while most of the remaining salmonines have converted to feeding on the more numerous juveniles stock component, including chinook, the largest annual alewife consumer population in open lake waters. Consequently, driving the shift in the age structure of the alewife stock to one consisting of age-! and Age-!! fish and a smattering of adults carrying the open lake population in Lake Michigan. MSU's Quantitative Fisheries Center has now developed a multi-species predator-prey model based on species specific salmonine predator stock and prey forage stock biomass that is replacing the old single species Chinook predaotor-alewife prey model used since 2013 to inform species specific annual plant rates, as well as co-factoring in wild origin production of chinook, coho, lake trout, and steelhead.
 
Fished one of the Lake Michigan tributaries that has one of the largest spring runs of steelhead. Actually, fish come and go from the short stretch of river below the dam and water control complex routinely from the late part of the salmon run when they come in to gourge on eggs until early March, when, for some reason there is about a two to three week window with few fish around. Kevin and I made the decision to fiish on Saturday, largely because all the other rivers were running high and dark. I knew this one would be a little higher, too, but still fishable based on experience gained over decades When we arrived we immediately ran into other fisherman in numbers. Our initial head-count at first light came in at 24, consequently playing fish, once on, was quite challenging in the strong current. I would peg the river at aroun 18' higher than normal levels. Black stone flies on a trailer behind orange, bubbegum, or chartruese egg flies were the ticket. Keven gave me a good lesson even though both of us were fishing chuck-and-duck rigs. He tallied 24 fish on over the morning, landing six. I hooked 14 fish to larnd four. All were wild fish with an intact adipose, so they went back. Sorry, no pics. We made few friends by releasing fish...
 
OK, so I got the part about coaster not being a different genetic strain but you kinda lost me on the second part.
Do I read correctly that invasive mussels removing plankton and prey availability are the driving factors?
 
When I was working for MSU on the mortality study at the Ludington Pumped Storage Facility we were running our open lake gillnets at sampling stations north and south of the plant. We caught a washed-out brook trout that was solely identifiable by the contrasting striping on its ventral fins, but really pale and 3YO by scale aging which should be accurate for salmonines that young. After checking the fish over for fin clips and finding none, we concluded that he was a fish that had flushed-out of a river. my point is that coasters do exist in the lower Great Lakes. That sadi, the majority of them are found in Lake Superpior. One thing I should have added was an MDNR genetic analysis of inshore caught "coaster" brook trout on the north shore of the U.P. conducted by the MDNR Essentially they found that these fish were a genetic amalgam of several populations of stream brook trout from the Salmon Trout River westward over to Keweenaw Bay, indicating that this open lake stock consisted of excess production from a variety of flash basin streams with low productivity, several of them forming anchor ice in severe winter, further diminishing their prodcutivity and conseqent carrying capacity.

Carl the easy answer to your second question is to simply point-out that Lake Superior, of all the Great Lakes, has the fewest invasive species including a near abence of Dreissenid mussels other than a colony near the mouth of the St Louis River over by Duluth, MN/Superior, Wi. that has thus far failed to expand, yet still survives, courtesy of the outflow plume of the St, Louis. In reality, other than their impacts on decline and disappearance of the deepwater amphipod, Diporeia sp., invasive mussels have diverted production rather tha 'removed" it from the water column. By displacing Diporeia sp. quagga mussels have short circuited the physical cycling of demersally trapped nutrients, outside of isothermic intervals when the entire water column is subject to wind driven mechanical mixing. Consequently, the nutrients "lost" to the system are actually sequestered within about a meter of the substrate in the invasive mussel colonies that now blanket the substrate, even soft-bottom substrate due to shell build-up forming a hard-pan cementum layer that mussels colonize. With this Baltic invader came round goby, and an invasive amphipod, Echinogammarus ischnus, that colonize the mussel beds. The mussels poop-out a packet of pseuo-feces that are fragmented by chironomid larvae and invasive amphipod grazing activity with all nutrients released quickly taken-up by filamentous algae that colonize the mussel colonies, basically a nearly intact little commensalistic colony of invasives. Steve Pothoven, NOAA Great Lakes lab. researcher worked-up some extimates to conclude that invasive inshore mussel colonies can filter the entire water column, top to bottom, at depths out to 90 meters during periods where wind and wave actiivity generated mixing of the water column was minimal, over an interval of a little over a week! Round goby are conseqently VERY abundant, far more than alewife used to be back in the 1970's. However, they have a caloric density roughly half that of an equivalent length alewife or smelt, obligating any fish species that opts to consume them to eat them at twice the rate to retain their conversion efficiency and growth rate. Now, toss-in the predation rates on round goby, per estimates made by the folks at MSU's Quantitative Fishery Center are so high in both Lakes Huron and Michigan that Round Goby seldom survive to Age-III where they are big enough to feed on quagga sp mussels, serving as a partial check to their expansion. Consequently biomass of invasiv mussels continues to increase as density declines inshore out to100M. Lake Huron is roughly half the Total Carbonate Hardness value of Lake Michigan, reducing both the production of round goby and their caloric density relative to Lake Michigan. The secondary conduit for biotic transfer of demersal energy back to surface waters in Lakes Michigan and Huron is Mysis diluviana, which has seen about a 79% decline in numbers as well. There used to b summer long functional stocks of large cladoceran zooplankton like Daphmia sp and Bosmina sp., even when alewife were dominant. Now, the zooplanktong stock shifts quickly over to the omnivorous copepod, Limnocalanus sp., particuarly in the northern portions of the basin and outside of the Bays de Noc. Basically this reflects that improved water clarity due to declines in biogenic turbidity values. Much like Alaska, several States encourage sport fishers to dump their fish carcasses back into the system offshore to stimulate productivity.
 
Carl, one other genetics study I should have mentioned was done on Isle Royale stocks of coaster brook trout which found that these fish were largely direct decendants of two stream populations, indicating that there is little mixing of genetic material for these isolated stocks. From what I recall they were the coaster stock for the Superior basin coaster rehab. Michigan no longer actively supports the effort and has been planting splake again in their waters- there is data that a small percentage of splake do not experience non-disjunction issues during meiotic cell divisiona and can consequently reproduce. View attachment Fall+2015+CoasterBT.JPGView attachment Hunter+fall brown+male.jpgView attachment L Superior Pike.jpg

Michigan now allows retention of one fish per day over 20" TL. We paddled kayaks from the Big Bay Harbor of refuge several miles along the shoreline to get out in front of the Salmon Trout discharge in early September. We were throwing Clouser minnows and a smelt imitation streamer for about two hours of fishing before the darkening horizon cloud build-up made us decide to scoot back to the marina. We caught and released seventeen coasters that were identical to this fish. Coasters now have other inshore predators to deal with beyond lake trout.

View attachment Hunter+fall brown+male.jpg
 
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When I was in Grad. school I was recruited to work on a stream survey crew MSU was sending to the Huron Mountains to estimate brook trout numbers in the Salmon Trout River within Huron Mountain Club property. Guy Fleischer and I had spent some time and effort building a second pulsed DC shocker that road in a little roto molded dingy. I think it was called a Sport Yak. The generator and collection tub were mounted in the boat with an array of three retractor reels on a board mounted just back of the bow to hold the cords for the cathodes with we epoxied into the ends of three fiberglass shafts. The cathodes were steel rod we bent via a jig into an elongated diamond pattern prior attaching to the electrical cord reels.

We did or marking run in late July and returned in September to make the recovery survey that would generate the first estimate. When we were checking through the guard shack one of the security people mentoned that there were some coasters at the lower falls, which was our starting station. That evening we made a thermos of java and hiked down to the falls to sit a watch for an hour or so. That was when I decided that this was the place I wanted to end my life. There is an account of a schooner trip that ran north of Marquette made by Peter White and some friends to fish "salmon trout" which they reportedly caught by the hundreds, but that was back in the period where lake trout demes spawned in all the rivers of the Great Lakes, too, removed via pitchfork by early settlers each fall until they, too, became quite sparse.
 
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