Chemical Characteristics

Due to the relatively shallow lake basin and heavy wind action, thermal stratification does not usually occur. Summer water temperatures are usually in the 24-26°C range. Alkalinity and pH values suggest that White Lake is well buffered and not particularly sensitive to acidic precipitation. In terms of trophic status, White Lake was considered as mildly eutrophic as early as 1969 (Ellah 1969). Eutrophic lakes are rich, biologically productive and have secchi disk readings of less than 3 metres and chlorophyll a values of greater than 6 ugl"'. Chlorophyll a values are indicative of high algal crops and algal blooms often occur during the summer. The diary of Peter's Point Fishing Club (see 'The Fishery') suggests that algae blooms occurred at least as early as 1940.

White Lake's shallow, "dish-shaped" basin and its low flushing rate make this system very productive from a biological basis. The nutrients and sediments which fuels the rich biological productivity in White Lake are thought to come from land runoff (45%), the atmosphere (42%), and shoreline development (13%) (Ferris 1985). The secchi disc measurements taken over time in White Lake show no clear trend (Figure 3). Chlorophyll 'a' values have fluctuated widely over time, but appear to have declined over the past 25 years. The amount of dissolved oxygen in the water column is a critical factor in determining the survival of many fish species. White Lake has sufficient dissolved oxygen to support warm-water fisheries. However, some surveys have shown that at water depths greater than 6 metres oxygen levels can fall below 5 ppm, a critical level for many fish (Ferris, 1985).

Several fisheries management issues have been identified on White Lake over the years. These include:

Water Levels - Controversy over the management of water levels has undoubtedly been the most prevalent issue on White Lake. Ministry of Natural Resources files include letters expressing concern about water level management dated in the early 1960's. Boaters and shoreline property owners prefer stable water levels during the summer and early fall. However, summer water level stabilization further reduces the natural flushing rate of the lake resulting in stagnant waters where silt and algae cover spawning shoals, resulting in water quality and fisheries concerns.

Accelerated eutrophication - White Lake has been considered to be moderately eutrophic for several years. Due to the shallow nature of this impoundment, its low flushing rate and the addition of nutrients from heavy shoreline development this process has been accelerated (Ferris 1985). Hamilton (1981) concluded that if nutrient loading was not significantly reduced, there would be the decline and loss of several species including walleye and possibly smallmouth bass.

Siltation of spawning shoals - Observations during 1959 and 1969 netting projects did not reveal any problems with siltation of shoals used by spawning walleye and smallmouth bass. In fact, Littkemann (1959) identified the presence of "numerous stony-rocky shores and shoals in different dimensions which provided good spawning grounds for walleye." The problem was first documented by Thomas (1975) and Bond (1977) concluded that encrustation of calcareous blue-green algae reduced the quality of walleye spawning shoals.

Impaired water quality - Ferris (1985) identified some water quality problems which included dissolved oxygen deficits in deeper (>6m) waters as well as some bacteriological contamination. The re-suspension of sediments from the lake-bottom by wind and wave action or by motor boat propellers has also been identified as an issue.

Shoreline development - Hamilton (1981) reviewed the dramatic increase in shoreline development from 1959-1980 and concluded this was a major cause in the accelerated rate of eutrophication. He believed that White Lake was an example of how unregulated cottage and shoreline development on a lake could have serious consequences on the fishery. Shoreline development was also identified as a problem by Ferris (1985) and vonRosen and McLeod (1985). Ferris recommended that backshore development be developed as an alternative to further lakeshore development in the future. There had also been previous recommendations to delay further lakeshore development until water quality and fisheries habitat issues had been resolved.

Shifts in fish community structure - Alteration of fish habitat and changes in lake trophic status have resulted in a shift in the resident fish community from species such as walleye and smallmouth bass which prefer mesotrophic conditions to those such as northern pike, panfish and largemouth bass which are more suited to eutrophic conditions. Walleye historically were the most highly sought species and were the mainstay of the local tourist industry at one time.

Conflicting resource uses- There are several conflicting resource uses on White Lake. These include anglers, boaters, shoreline property owners, the local tourist industries and hydro considerations. Ferris (1985) reported that 32% of lake use was from boaters while 68% was from anglers. Nowhere is the conflict more evident than with water level regulation and fish habitat protection.

Overexploitation - Overexploitation of highly sought sport fish stocks, particularly walleye, has been identified as a concern by vonRosen and McLeod (1985), vonRosen (1989) and Ferris (1985) Excessive algae and aquatic vegetation - Excessive mats of algae and aquatic vegetation have been identified as a summer problem by lake residents on several occasions.