Two Decades of Steelhead Research

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Portage Creek, Ontario
After the 20-minute hike through some rugged Northwestern Ontario terrain, we arrived at a place coined “The Falls”, a beautiful portion of the stream, with a set of step like cascading falls flowing into a picture-perfect pool. We were on Portage Creek, the site of a long-standing steelhead research project, about to start out day sampling Lake Superior steelhead.

I readied my rod, unpacking it after the trek through the tangled bush, and got ready for my first drift. I tucked a number 8 egg hook into a freshly tied spawn sack below a float, and made my first drift. As it slipped downstream below the falls, perfectly on the seam, between rapidly flowing water and calmer water, it hesitated, dipping slightly below the surface. I leaned back on my rod, and set the hook into a feisty, chrome Lake Superior steelhead. After a brief, but intense battle, the fish was landed, and we quickly setup to sample and tag the fish, to add to the valuable data for the program.

Steelhead 101
Steelhead are a migratory rainbow trout that were introduced into Lake Superior in the late 1800’s. They are now well established and naturally reproduce in Lake Superior. Steelhead spend one to three years in the stream, and another one to three years in Lake Superior before they reach maturity. They have a very strong homing instinct, returning in the spring to spawn in the stream they were originally from.

History of Portage Creek
Portage Creek is a small cold water tributary to Black Bay, Lake Superior, forty kilometres east of Thunder Bay, Ontario. In the early 1990’s, a steelhead assessment study was conducted on Canadian tributaries of Lake Superior, and Portage Creek had the highest harvest levels, potentially endangering the health of this wild steelhead population. A partnership was struck with landowners and the Ministry of Natural Resources to restrict access to the property surrounding the stream. This essentially closed the lower end of the stream to fishing, allowing the MNR to conduct a controlled steelhead research study. This study provides a long term (25 years) data set that includes annual population estimates and life history strategies (stream life, lake life, age, repeat spawning and maturity). This long term study can be used to index the health of steelhead populations in other Black Bay tributaries.

In the early stages, the steelhead population was estimated to be 500 fish in 1992. Following a ten year closure the adult population had increased to over 2,000 fish, but from 2007 to 2015 the population had declined at an alarming rate, to 250 adults. The low population in the early 1990’s was due to over harvest, where the decline in the last ten years seems to be likely due to poor survival of juveniles in Black Bay.

The population growth in the 1990’s was a result of the reduction in harvest after the river was protected in the 90’s, as well as strong year classes that produced good numbers of fish. There were several ideal springs, with excellent water and weather conditions, with healthy fish populations that produced good numbers of juveniles. Since the population boom in the early 2000’s, numbers have steadily been on the decline.

Environmental factors play a role, with reduced water flow and increased water temperatures, as well as poor survival of juvenile steelhead in Black Bay of Lake Superior. There have been very low numbers of offspring, and low survival rates of fish making it to be first time spawners. There is little recruitment coming back into the population; historically the stream would produce good numbers of fish, they would survive in the lake and return to the stream to spawn.

Looking back to 2004, this was the last year with a solid year class. When steelhead are three years old, they generally return to the system as first time spawners, and in 2004 these three year old fish represented about 1,000 fish in the river; demonstrating excellent recruitment. As of now, there is very low recruitment, and very low numbers of these three year old first time spawners returning to the system, in fact showing the lowest numbers ever produced in the creek. There is very little survival from the first year in the stream to becoming first time spawners; this may be due to significantly reduced survival in the lake of these immature steelhead.

Black Bay Factors
Black Bay is a rather unique part of Lake Superior, with warmer, shallower water, and a growing population of perch and walleye. The decline of steelhead seems unique to the Black bay basin itself, and is not apparent on nearby areas, such as the Thunder Bay basin to the West, and Nipigon Bay to the East. Black Bay used to have a healthy walleye population, which essentially collapsed a number of years ago, and the commercial and sport fishery was closed to protect recovering walleye stocks. The perch and walleye seem to be recovering quite well, although walleye fishing is still closed in a large portion of the bay. The Yellow Perch fishery is thriving, with Black Bay jumbo perch becoming a huge draw for anglers in the winter months, with several commercial hut rental operations taking full advantage of this fishery. This rise in the perch and walleye population seems to coincide with the decline of the steelhead, and may be a contributing factor to low steelhead numbers; whether competing for food in the bay, or young steelhead are being preyed upon, something has changed in Black Bay in recent years for the steelhead.

The Study
For this study, fish are caught by anglers, netted and biologically sampled (length, sex and scale sampled) and tagged. Members of the North Shore Steelhead Association along with MNR staff are involved in this partnership, and take part in the angling and sampling together. The scale samples can show life history information; years in the stream and the lake, age, and number of spawning events. A tag is sewn into the back of the fish, and a fin is also clipped; a different fin is clipped each year, which will show if the fish has been sampled during a previous year in case the tag is lost.

After spending time on this stream for over 15 years, I have a real love and passion for the stream and the project, and hope to see another upturn in the Portage Creek steelhead population. The study will hopefully continue in the future, and continue to provide valuable steelhead research.

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