Use of rehabilitation experiments to understand the recovery dynamics of acid-stressed fish populations.
We used rehabilitation experiments involving the stocking of 2 native sportfish, lake trout (Salvelinus namaycush) and smallmouth bass (Micropterus dolomieu), in combination with recent fish community surveys, to study the recovery dynamics of fish populations in acid-stressed lakes near Sudbury and Killarney, Ontario, Canada. Population recovery rates differed between the 2 species. Introduced lake trout did poorly in species-rich lakes and exhibited slower growth, lower survival and delayed recruitment. Smallmouth bass, in contrast, readily colonized species-rich lakes. The biomass of natural smallmouth bass recruits increased to reference lake levels within 5 years following water quality recovery and spawning by stocked fish, whereas the biomass of natural lake trout recruits remained well below reference levels 5-15 years after water quality recovery and spawning by adults occurred. We document introductions by anglers of smallmouth bass into acid-damaged lake trout lakes, including some lakes that did not contain bass prior to acidification. This range expansion of a warm-water species (bass) that can alter food-web structure and reduce the growth of a cold-water species (trout), illustrates the potential for the combination of climate warming and species introductions to greatly alter the biological recovery endpoints in acid-stressed lakes.
Snucins
Ed
E
Department of Biology, Laurentian University, Sudbury, Ontario, Canada. esnucins@vianet.on.ca
Gunn
John M
JM
D015258:Acid Rain / Q000009:adverse effects*; D000818:Animals; D001492:Bass; D003625:Data Collection; D004784:Environmental Monitoring; D005260:Female; D005398:Fisheries; D008297:Male; D011157:Population Dynamics; D012098:Reproduction; D016019:Survival Analysis; D014337:Trout; D014876:Water Pollution / Q000517:prevention & control*
D015258:Acid Rain