1. Project Title: Creating Upwellings as Habitat for Incubation of Eyed Stage Brook Trout (Salvelinus fontinalis) Eggs
2. Contact
Lee E. Newman
U.S. Fish and Wildlife Service, Ashland Fishery Resources Office, 2800 E. Lakeshore Dr., Ashland, WI 54806, USA
Tel.: (715) 682-6185; FAX: (715) 682-8499
3. Agencies Involved
Grand Portage and Red Cliff Bands of Lake Superior Chippewa
4. Restoration Goal
Create spawning habitat capable of incubating eyed brook trout eggs to hatch and emergence.
5. Project Type
Reintroduction of an extirpated stock of brook trout (Lake Superior "coaster").
6. Background and Rationale
Anadromous runs of large brook trout (locally called "coasters") were once common and widespread in Lake Superior and its tributaries (Smith and Moyle 1944). Highly prized by anglers and sensitive to habitat perturbations, coaster populations were decimated by 1900. Currently, only a few remnant stocks are known to exist in the Lake Superior basin.
At the request of, and in cooperation with the Grand Portage and Red Cliff Bands of Lake Superior Chippewa, the USFWS initiated experimental management projects directed toward restoration of coaster brook trout in parts of Lake Superior from which they were extirpated.
Attempts have been made since the early 1900's to restore Lake Superior coaster populations by stocking hatchery fish (Smith and Moyle 1944). Those attempts have produced very low returns and provided no evidence of reproduction. Speculation is that the lack of success was caused by the use of an inappropriate strain of brook trout, lack of "wild" fitness of hatchery fish, or failure of hatchery fish to properly imprint homing instincts.
We used the most closely linked genetic population available (the Nipigon strain) for the restoration efforts, and we used the earliest life stage possible (eyed egg) to maximize imprinting and synchronization with natural food supplies.
Brook trout preference for spawning on springs or upwellings has been widely reported (Raleigh 1982). We attempted to locate the type of habitats where native populations might have spawned originally, then use or create upwellings simulating typical brook trout spawning habitat. We also created redds without upwelling flows to provide a comparison. We then introduced eyed Nipigon strain brook trout eggs into the substrate and monitored the hatch rates by placing egg incubators in with the eggs. We did not attempt to quantify fry emergence. Egg introductions were begun in Grand Portage streams in January 1992, and in Lake Superior (Red Cliff Reservation) in January 1994.
7. Regulatory Considerations
As this cooperative project took place on Tribal lands, no permits were required.
8. Criteria
Brook trout are known to spawn in a variety of riverine and lentic habitats (Raleigh 1982). Other sources suggest that brook trout may reproduce in streams where upwellings are not present (Hale and Hilden 1969).
Habitat usually includes:
areas of ground water upwelling;
gravel, rock, and sand substrate;
minimal amounts of silt or fine sediment;
temperatures from 4.5 to 10°C.
9. Project Design
Using native substrates, we constructed artificial spawning redds in three distinct environments; a stream with no apparent groundwater nearby, a stream at its groundwater source and a nearshore, shoal area of Lake Superior where groundwater seepage occurred just above the waterline. In Lake Superior we raked together gravel and stone that occurred in about 0.4 m depth to form a redd about 1 m wide and 0.2 m deep. In both of the streams, we created the same type of redds, but in two sites we also created upwelling through the substrate by installing PVC pipe underneath and upstream to provide a gravity feed.
10. Implementation
Eyed Nipigon strain brook trout eggs were provided for this project by the Ontario Ministry of Natural Resources from the Dorion Fish Culture Station. Eggs from this source reach eyed stage around January 1.
Artificial redds were prepared on chosen sites within one day before the arrival of the eggs. In all sites the substrate consisted of coarse sand, gravel and small rock.
Eggs were implanted in the created redds by inserting a 1.3 m length of 5.1 cm diameter PVC pipe into the bed to a depth of 5-10 cm and pouring eggs and water down the pipe. Eggs were inserted in this manner in several spots in each redd (Gustafson-Marjanen and Moring 1984). Egg incubators containing a known number of eggs were placed in each redd along with the eggs, as a means of evaluating hatch rate.
We projected an approximate hatch date for each site based on the actual thermal units that eggs were subjected to. We removed incubators within one week following the projected hatch date. Hatch rate was determined as the number of living fry found in an incubator divided by the total number of eggs placed in the incubator.
11. Degree of Environmental Intervention
Primarily, microhabitats in the substrate disturbed were affected. On site disturbance was limited to an area of less than 2 m2 for each site. Hand tools (shovel and rake) were used to make modifications. As silt was limited in the chosen sites, little siltation occurred.
12. Cost
Labor and Materials $120
Biological Assessment $ 80
Total$200
13. Biological Assessment
Evaluation of hatch success in incubators. Survey of streams and nearshore Lake Superior in stocked areas to confirm presence of year-classes of brook trout. As trout mature, sites will be monitored for return of spawning adults.
14. Measures of Success
If brook trout fry can be successfully and inexpensively produced in artificial or improved habitats, the technique may have applicability for reintroducing extirpated populations. We would expect that fry produced by direct stocking of eyed eggs should exhibit more "wild" characteristics and be more likely to establish reproducing populations than stocked hatchery fish.
Evaluation of hatch rate in incubators showed high survival to fry stage (84-93%) in all sites except where the redd was improperly placed and dewatering and freezing occurred. No attempt was made to verify the comparability of hatch rates in the incubators with that of the eggs in surrounding substrate. However, from the low number of dead eggs observed in the redds and the numerous fry we observed in the areas of the redds when incubators were retrieved, we suspect that hatch rates may have been similar.
The high hatch rates observed here, both where upwellings were used and where they were not, suggest that this technique might have advantages in cost and quality of the fish produced as compared to the use of Vibert Boxes for hatching, or by the use of hatchery fingerlings.
Success Rating: 4
but unknown at this time whether fish produced will survive and establish a naturally reproducing population. Also unknown whether adults will return and spawn on created redds.
15. Key References
Gustafson-Marjanen, K.I., and Moring, J.R. 1984. SFA 30(1) Construction of artificial redds for evaluating survival of Atlantic salmon eggs and alevins. Amer. J. Fish Manage. 4(4A): 455-461.
Raleigh, R.F. 1982. Habitat suitability index models: Brook trout. U.S. Dept. Int., Fish Wildl. Serv. FWS/OBS-82/10.24: 42p.
Smith, L.L., and Moyle, J.B. 1944. A biological survey and fishery management plan for the streams of the Lake Superior north shore watershed. Minn. Dep. Conserv., Div. Game Fish. Tech. Bull. No. 1.
Correct citation for this contribution:
Newman, L.E. 1995. Creating upwellings as habitat for incubation of eyed stage brook trout (Salvelinus fontinalis) eggs, p. 69-72. In J.R.M. Kelso and J.H. Hartig [editors]. Methods of modifying habitat to benefit the Great Lakes ecosystem. CISTI (Can. Inst. Sci. Tech. Inf.) Occas. Pap. No. 1.