Adaptive stocking strategies of Hybrid Striped Bass in a Nebraska reservoir impacted by White Perch

Abstract

Branched Oak Reservoir is the largest reservoir in eastern Nebraska and provides an important recreational fishery to large urban centers including Omaha and Lincoln. Hybrid Striped Bass Morone saxatilis × Morone chrysops are an important component of the recreational fishery, but this population appears to have been negatively impacted following the introduction and subsequent overabundance of invasive White Perch Morone americana in the mid-1990s. This study analyzed long-term standardized sampling and stocking data from Branched Oak Reservoir to evaluate Hybrid Striped Bass stocking strategies in the presence of White Perch. The spring age-0 stocking era from 1988 to 1997 consisted largely of fry and fingerling stockings. From 1998 to 2015, stockings were adapted to advanced fall age-0s with mean ± SE TL of 146 ± 7 mm. From 2016 to 2019, advanced spring age-1 Hybrid Striped Bass defined the third stocking era with mean ± SE TL of 178 ± 13 mm. Age-1 Hybrid Striped Bass CPUE differed among stocking eras (KW = 9.81, P = 0.007) as mean ± SE CPUEage-1 was 2 ± 1 fish per net night during the spring age-0 era, 1 ± 1 fish per net night during the fall age-0 era, and 3 ± 1 per net night during the spring age-1 era. Hybrid Striped Bass CPUEQP was different among eras (KW = 13.30, P = 0.001). None of the five abiotic factors assessed exhibited significant relationships to Hybrid Striped Bass CPUEage-1, and the strongest relationship (spring temperature) only had an r 2 value of 0.046. Information obtained from this study validates the current management decision to stock spring age-1 Hybrid Striped Bass based on the present White Perch abundances, and observed recruitment of Hybrid Striped Bass.