Theses and Dissertations


Title: Improved Methods of Spawning and Intensive Culture of Bluegill, Lepomis macrochirus

Name: Matthews, Michael David

Degree: MS

Chair: Leonard L. Lovshin

Resides:

University: Auburn University

Location: Auburn, Alabama

Date: 2000

Pages: 82

Keywords: bluegill culture,bass management,intensive culture,spawning

Abstract:

Studies to improve bluegill spawning, fry nursing, and fingerling production to 12 cm within 1 year of hatch were conducted during the two-year study. Six 205 m2 ponds were used to spawn broodstock. In 1998, spawning ponds were stocked with 1,700 males and 2,580 females/ha. Fry were harvested 28 d after stocking broodfish by draining the water in 3 ponds to a catch basin and removing the fry with dip nets (single-harvest) or by partial seine harvest of fry in 3 ponds before draining the pond water to a catch basin to remove remaining fry (multiple harvests). The average number of fry collected with multiple harvests was 607,300 fry/ha, while 856,100 fry/ha were collected with single- harvest. In 1999, three 205 m2 spawning ponds were stocked with 3,320 males and 3,320 females/ha (high density) and three 205 m2 ponds received 1,850 males and 1,850 females/ha (low density). The average number of fry collected from the high and low density treatments were 435,800 fry/ha and 618,000 fry/ha, respectively. Fry were counted and restocked into six fertilized, 0.04-ha ponds at 375,000 and 750,000/ha in 1998 and at 250,000 and 375,000/ha in 1999. Fish were fed 3% body weight twice daily with powdered, crumbled, and pelleted feeds in both years. Bluegill were cultured for 90 d the first year and 170 d the second year and were graded into small, intermediate, and large size classes at harvest. In 1998, 30% of the bluegill fry reached an average of 6.8 g and 60% reached an average of 1.7 g in ponds stocked with 375,000 fry/ha. In the ponds stocked with 750,000 fry/ha, 80% of the bluegill reached an average of 0.7 g. In 1999, 25 and 57% of the bluegill population averaged 4.5 g and 1.8 g in the ponds with 250,000 fry/ha and in ponds with 375,000 fry/ha, 86% reached an average of 0.7 g and 10% of the population averaged 4.8 g, respectively. Fry survival averaged 65% in 1998 and 75% in 1999. Six, 0.04-ha earthen ponds were stocked with 47,000 bluegill fingerlings/ha and cultured for 200 d in 1998-1999. Three of the ponds were stocked with bluegill averaging 2 g and three ponds were stocked with bluegill averaging 6 g. Fish were fed initially a 48% protein, 1.6-mm diameter floating diet and later a 36% protein, 3.1-mm diameter floating catfish feed twice a day to satiation when weather permitted. Mean yield, individual weight, survival, and feed conversion efficiency at harvest for 2 g and 6 g bluegill was 265 kg/ha, 12 g, 50%, and 1.2 and 875 kg/ha, 28 g, 68%, and 1.3, respectively. Only one percent of the 2 g bluegill reached 12 cm and 30% of the 6 g bluegill reached 12 cm. Average lengths of the 2 g and 6 g bluegill at harvest were 8.7 cm and 11.1 cm, respectively. Neither the 2 g nor 6 g bluegill reached an average length of 12 cm I year from hatch when stocked at 47,000/ha.

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