Limnological Survey of Three New Brunswick Lakes: Louis Lake,
Burk Lake and an Unnamed Lake
Summary
As part of a study to determine the suitability of three lakes, located within the Miramichi drainage in Northumberland County, New Brunswick, to support healthy and productive cold-water fish populations, a limnological survey of each lake was carried out on August 18 and 19, 2008. A secondary objective of the surveys was to collect information required to evaluate the status of the lakes with respect to their general health. The
limnological parameters measured included depth profiles of water temperature, conductivity, dissolved oxygen, chlorophyll a concentration, pH, and micronutrient concentrations. Samples for analysis of zooplankton composition were also collected.
The results of the survey indicate that two of the lakes, Louis and Burk, were thermally stratified and contained areas of suitable summer cold water refugia located within the thermocline. The third lake surveyed, Unnamed Lake, was not thermally stratified due to its shallowness (less than two metres depth), and did not contain any cold water habitat making it unlikely to support a productive salmonid population during the summer months.
A general assessment of the health of each lake revealed all to be moderately productive with pH and alkalinity values that indicate none of the lakes to have been impacted by acid precipitation.
Further evaluation of the lakes related to their potential to support productive salmonid populations should include determining if additional cold water habitats exist resulting from cold groundwater inputs entering the bottom of each lake, or from groundwater-fed streams entering along the lake shorelines. In addition, studies should be conducted to determine the extent and suitability of spawning areas associated with each lake.