Effects of lake productivity, climate warming, and intraspecific density on growth and growth patterns of black crappie in southern Minnesota lakes

Growth and growth patterns of black crappie Pomoxis nigromaculatus) from a diverse set of 42 lakes in the southern half of Minnesota, and effects of lake productivity, climate warming, and intraspecific density on growth were determined First-year growth increments decreased with increasing mean depth and increased with increasing chlorophyll-a concentration until concentrations reached around 100 mu g/L. At concentrations above 100 mu g/L, first-year growth decreased with increasing chlorophyll-il concentration. The number of years needed to grow to 200 mm (QAGE) was lower in lakes with low (< 3.8 per lift) catch per lift (CPUE) of black crappie in gill nets set in summer. Second- and third-year growth increments explained 71% of the variation in QAGE among lakes, but first-year growth did not explain any additional variation. Black crappie with sigmoidal growth patterns (second- or third-year increments greater than or equal to first-year increments) reached 200 mm significantly faster than black crappie with nonsigmoidal growth (first-year growth increments were longest). Black crappie exhibited sigmoidal growth in lakes with low gill net CPUE of black crappie, and nonsigmoidal growth occurred in lakes with high gill net CPUE. Growth and growth patterns were unrelated to climate warming.