Brook Trout Ecology
The research program on brook trout is entering a new stage.
For the next two years
we are focusing on recording and mapping the 3D position of brook trout
in two Algonquin Park lakes - including common suckers in one lake.
The purpose of the work is to better understand the availability of
brook trout to monitoring gear and to test some hypotheses about
habitat selection on daily and longer time scales.
The photo to the right is of a 50+ cm male brook trout taken during the
spawning season. Where does he live at other times of the year and what
habitats are being used at daily and seasonal time-scales?
Some more details can be found on the Acoustic Array page.
Some past projects...
1. Mating system
A detailed study of the brook trout mating system was conducted on Scott Lake by Paul Blanchfield as part of his Ph.D. thesis. Brook trout have a competitive mating system based on access to groundwater for the location of spawning redds. The number of suitable spawning redds is limited by local hydrology and not related to lake size. Within the mating system, females prepare sites, males compete for proximity to spawning females and the spawning season itself lasts for weeks. The requirement of groundwater seepage provides a univariate habitat measure as 'clean' criterion for site choice as opposed to multivariate habitat measures used by other salmonines. Check out the publication page for articles stemming from this work.
2. Young-of-year habitat and movements
A series of field studies described the habitat and diffusive movements of yoy brook trout away from spawning sites. A unique situation with respect to young-of-year ecology in salmonines can be addressed with brook trout since there are very few (often only one) spawning areas for brook trout in lakes ~ the single source provides a point of departure for young brook trout and overcomes one of the great difficulties of addressing various questions in salmonine ecology..... where did the young fish originate? In a series of publicaions from Peter Biro and Matt Coombs, as part of their M.Sc. work, the kinds of habitat and the nature of their movements away from single sources was investigated resulting in a lot of insight into their early ecology. Check the journal publications page.
3. Life history and coasters
A summary of life history variation in brook trout provided more general insight into the Coaster brook trout phenomenon in Lake Superior. One of challenges with coasters is the lack of data on their life history. Another challenge is the need to explain the coaster phenomenon at the same time, and in the same way, as the phenomenon of brook trout size variation generally. Why is it so variable? Brook trout matching the growth, longevity, and size of ooasters can be found in lots of locations throughout their northern range... they just don't live in watersheds along the Lake Superior coast. Assembling a life history database and thinking about the problem led to a conclusion that brook trout are effectively products of the food web where they live - and where individuals live in watersheds is likely determined by their basal metabolic rate. So-called 'winners' may be individual brook trout capable of sustaining themselves in low productivity headwaters without incurring the risk of movement. Others requiring higher food input (ie., higher metabolic rate) move to habitats that meet those demands - and this almost always is to more productive habitats leading to higher trophic position and larger body size.
At watershed scales, fish that live in the lower and more productive reaches (including estuaries) will grow faster and always be larger than conspecifics higher in the watershed. Is phenotypic variation in metabolic rate (and movements) behind this phenomenon? Is that why diagrams linking movements of brook trout and other fish in estuaries look like 'spagetti' - are individuals trying to match metabolic rate to habitat productivity leading to a distinct lack of generality in these movement diagrams?
4. Brook trout food webs
Recent Ph.D. research by Dave Browne with Joe Rasmussen (when Joe was at McGill) has provided a tremendous look inside food web variation in brook trout lakes. The species is very flexible in its trophic position and this stems from the fish assemblage co-existing with brook trout. Publications from Dave's work are in press or coming out soon and promise lots of new insights in this area of brook trout ecology.
5. The Forest Fish:
The purpose of the Forest Fish Project was to link topographic measures of forested watersheds with groundwater habitat used by young-of-year brook trout in lakes. The work is largely complete now but there is a website that summarizes a lot of the research findings. Read more here.
The topographic index outlined in the Forest Fish project and in Borwick et al. (2006; CFJAS 63:239-253) has potential use in many areas of fish & habitat ecology. It was used to provide a more precise protection status for hydrologically relevant forested sub-watersheds around brook trout lakes in Algonquin Park.