The Science Seminar Series: November 20, 2008

The life history of the crayfish, Procambarus spiculifer, in the Alapahoochee River Basin.

Phil Hightower

Department of Biology

Valdosta State University

Place: Powell Hall
Time: 4:00 -5:00pm

Abstract:

A fifteen month life history analysis was conducted on a population of Procambarus spiculifer in the Alapahoochee River. The crayfish, P. spiculifer, inhabits lotic waters in portions of Georgia, Florida, and Alabama. Cephalothorax lengths ranged from 6.07 mm to 59.80 mm and weights varied from 0.02 g to 53.37 g. The average sizes of adults were 45.90 mm for form I males, 42.77 mm for form II males, and 38.43 mm for mature females. Form I males and mature females were collected year round. Relationships of cephalothorax lengths with body weights, chelae lengths, cephalothorax widths, ovarian eggs, and abdominal eggs were examined. Carapace width and chelae width comparisons among sex classes were also performed. Peak juvenile introductions into the population occurred in June, late fall, and early winter. A maximum life span of two to three years was determined.

Reproductive maturity occurs around the ages of 13 to 15 months. Ovarian egg counts averaged 602 eggs (n = 61) and abdominal egg counts in the laboratory averaged 464 eggs (n = 6). Abdominal egg diameters averaged 1.74 mm (n = 120) with a range of 1.04 mm to 2.03 mm. Females have the ability to reproduce more than once and new ova begin development immediately after a clutch of eggs is laid. The right vas deferens is probably the only functional one in P. spiculifer. GSIs were determined for mature females, immature females, form I males, and form II males. A gastric stomach analysis revealed that both males (n = 20) and females (n = 20) consume more vegetal matter than animal matter in their diet.