Monitoring & Assessment ~ Landscapes & Lakescapes
We've worked on a number of fish population monitoring and assessment projects. Different habitats are incorporated in this research that has different lakescape and landscape scales. Below are some of the current projects...
Costello Creek/Sproule Bay Fish Survey
In 2009, the survey of Costello Creek and Sproule Bay near the fish lab was surveyed in May as it was in 2008. Three-pass surveys were completed in May, July, and September of 2008 and again in May 2009. Multi-pass methodologies are good for estimating occupancy as a function of habitat and species assemblage.
The watershed drains into the southern end of Lake Opeongo (Sproule Bay where Harkness Lab is located), initially as a stream system draining Costello Lake through a series of beaver ponds and wetlands largely definded as a mix of bluejoint grass and speckled alder, and finally as a spruce bog system reaching Sproule Bay. An image of Sproule Bay greets web visitors when the Harkness site first appears on their computer as an "Enter" page.
Among the many new insights gained from a formal occupancy analysis, one interesting feature was the zonation of the watershed by brown bullhead ~ apparently a relatively common feature of catfish dominated systems but one that has received very little research. The spring survey will be completed in '09 and the robust method of occupancy analysis used in analyzing '08 and '09 data.
Fish assemblages and occupancy in the shallow littoral zone of lakes
In 2008, we completed a small fish survey of the Opeongo shoreline in each Arm to estimate occupancy patterns of juvenile stages of perch, pumpkinseed sunfish, and smallmouth bass. In a twist of the 3-pass methodology, each site was sampled simultaneously with minnow traps separated by 2-3 meters downslope beginning with the shallow littoral (< 1m) and down to about 2m. Habitat covariates such as substrate and effective fetch were recorded
Where are the sculpins?:
Lake Opeongo is listed as one of the few lakes in Algonquin Park to have sculpins. This is not the real state of their distribution, instead it reflects limited sampling effort in other lakes. The three species listed are mottled, slimy and spoonhead sculpins ~ in 2006 we only captured slimy sculpins in each arm of Opeongo between 20 and 40+ meters deep. Spoonhead sculpins should be distributed in historic Great Lakes drainage systems in the north end of Algonquin Park while slimy sculpins should be distributed in lakes of central Algonquin Park.
We completed a depth stratified sampling design in 2007 to determine presence/absence of sculpins in Opeongo. The design layout and analysis will be based on new methods stemming from occupancy analysis.
Line transect distance sampling in the shallow littoral zone:
Distance sampling is a method of estimating abundance based on a probability of detecting an animal as a function of distance from a survey line. We've used this approach in the shallow littoral zone of lakes to estimate the density of cyprinid fish in complex, shallow habitats.
In 2007, we returned to Scott Lake in Algonquin Park to resurvey the nearshore fish community using line transect distance sampling.
In general, underwater visual count (UVC) methods hold great promise for relatively shallow surveys of fish in their natural habitat - a level of resolution not attainable by indirect passive netting gear. In our work at Harkness, we refer to the "C" in UVC as counts as opposed to census that other researchers use - implying a detection probability of 1.0 in their surveys. Until perfect detection is demonstrated it is more prudent to refer to the data as counts not censuses.
A better minnow trap:
Minnow traps a common method of capturing small fish. Doug Brown has designed and built a better one than the standard type ~ the Harkness Trap. In the summer of 2006, students ran a comparison of catch rates of the two types in nearshore habitats of Sproule Bay, Lake Opeongo.
The results weren't even close - the Harkness trap had higher catches and caught more species than the standard trap. A unique staircase design of trap comparison will be used to analyze the data from this project.
Back To Aquatic Projects.