Nebraska Cooperative Fish & Wildlife Research Unit

Date of this Version

1994

PROC. S.D. ACAD. SCI. VOL. 73 (1994)

Brown trout (Salmo trutta) were sampled in Gary Creek, South

Dakota, during the fall of 1988 and 1990-1993 using a backpack-mounted,

pulsed-DC electrofishing unit. Relative abundance of

stock-length (≥15 cm) brown trout was not significantly different

among years; however. size structure increased. Brown trout proportional

stock density (PSD; percentage of 15-cm and longer fish that

are also longer than 23 cm) was 50 and relative stock density or

preferred-length fish (RSD-P; percentage of 15-cm and longer fish

that are also longer than 30 cm) was 4 in 1988. In 1993, PSD was 100

and RSD-P was 61. Natural reproduction of brown trout has declined

over the 1988-1993 time period. However. the stream was annually

stocked with catchable-size (20-23 em) brown trout. Habitat may be

limiting natural reproduction and recruitment. While Gary Creek

might be considered a "quality" brown trout population for a stocked

population, the high PSD certainly reflects the lack of natural

recruitment in recent years.

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