Distribution and Population Attributes of Gulf Sturgeon in the Lower Pearl River System, Louisiana

Seven reaches of the lower Pearl River system were sampled with bottom set gill nets from 1992 through 1995. One hundred fifty-eight Gulf sturgeon (Acipenser oxyrinchus desotoi) were captured in 3 reaches. Mean fork length (FL) was 734 mm, and weight (W, g) to length (FL, mm) relation was: W = 1.786 x lO^CFL)3204. Mean weight loss during summer was 1.9 g/day. Ninety-two percent of Gulf sturgeon were captured in the West Middle River reach which is comprised of deep holes and little current. Radio telemetry indicated that the West Middle River was an important summer habitat for juveniles and subadults. Estimated mean summer population size in the West Middle River, determined from mark and recapture, ranged from 67 to 124 individuals, but low intra-year tag return indicated this may be part of a larger population. Annuli on pectoral fin rays were formed during May-July and 94% of fish aged were <6 years old. Adults (those >1.2 m FL) were scarce, suggesting excessive mortality.

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