Survival, reproduction, and recruitment of gizzard shad in South Dakota glacial lakes

South Dakota (SD) represents the northwestern edge of gizzard shad’s Dorosoma cepedianum (GZD) native range; however, natural range expansion and overwinter survival has recently been documented in SD.  Research objectives were to 1) determine the extent of GZD survival, reproduction, and recruitment after annual introductions of adult, pre-spawn, GZD in two SD glacial lakes and 2) compare levels of recruitment between the two stocked lakes and other SD systems.  In 2008 and 2009 adult, pre-spawn GZD were stocked and successfully spawned in East Krause and Middle Lynn lakes.  Mean (±SE) larval abundances (#/100m³) were 3.87 (±1.87) and 1.72 (±0.89) in East Krause and 0.79 (±0.22) and 0.17 (±0.11) in Middle Lynn in 2008 and 2009 respectively.  These values were slightly lower than naturally recruiting SD reservoir populations and slightly higher than a naturally invaded SD lake.  Survival to fall age 0 was documented in both lakes in 2008 with mean total lengths of age 0 shad being 122 mm (±5.5) in East Krause and 109 (±4.4) in Middle Lynn.  In 2009, fall age 0 GZD were only documented in Middle Lynn; mean total length was 123 mm (±0.9).  No overwinter survival of adults or juveniles was documented during 2008-2009.