James W. Avault

Preservation of Channel Catfish Sperm

Abstract Three activators, eight extenders, and three protective agents at two concentration levels each were used to determine the best combination that will maintain in storage the viability of channel catfish (Ictalurus punctatus) sperm cells. There was a highly significant (P < 0.01) difference in motility score among activators. Saline (0.65%) gave the highest motility score. Extended sperm cells became motile when activated after 2 months of storage at 4 C. Extender I (Truscott and Idlers Hfx #1) with 10% dimethyl sulfoxide (DMSO) and 2 hours equilibration produced the highest motility scores after freezing of 24 hours or 1 week. Freezing rate was controlled by placing vials of sperm in a double-layered, kapok-lined paper bag and freezing at the height of 127 mm above the liquid nitrogen level.

Acute Toxicity of Permethrin to Several Aquatic Animals

Abstract Acute toxicity tests were conducted on permethrin (Pounce(R)), a synthetic pyrethroid, by using 8-12- and 20-30-mm Louisiana red swamp crayfish (Procambarus clarkii), fry channel catfish (Ictalurus punctatus), fingerling largemouth bass (Micropterus salmoides), mosquitofish (Gambusia affinis), and bullfrog tadpoles (Rana catesbeiana). The 96-h LC50 values were 0.39, 0.62, 1.1, 8.5, 15.0, and 7,033 μg/liter, respectively.

Food Habits, Length-Weight Relationship, Condition Factor, and Growth of Juvenile Red Drum, Sciaenops ocellata, in Louisiana

Abstract Food habits of 568 juvenile red drum, Sciaenops ocellata (Linnaeus), ranging from 8.0 to 183.0 mm standard length, were determined during the time the fish utilized a Louisiana salt marsh as a nursery area. Potentially available food organisms were sampled during the 7-mo study. Some degree of selectivity by juvenile red drum was demonstrated, but generally the most abundant organisms of an edible size were utilized most heavily. Changes in food with increasing size can be described in three phases: 1) red drum less than 15 mm ate zooplankton; 2) between 15 mm and 75 mm the red drum ate mostly small bottom invertebrates and the young of other fish; 3) red drum larger than 75 mm ate decapods (crabs and shrimp) and fish. Some differences between day and night feeding were found. For red drum 65 to 85 mm the dominant food eaten was grass shrimp during the day, whereas at night it was fish. The length-weight relationship was log W = −7.2052 + (4.1913) (log L). The average coefficient of condition was...

Agricultural By-Products as Supplemental Feed for Crayfish, Procambarus clarkii

Abstract Growth of crayfish (Procambarus clarkii) fed six agricultural by-products was determined in the laboratory. In addition, the aerobic breakdown of 10 by-products was monitored to evaluate nutritive changes in their composition. Dried sweet potato vines produced the highest final average weight of crayfish, followed by sweet potato trimmings, rice stubble, and rye hay. Crayfish fed soybean stubble and dried sugarcane stalks grew poorly. A decrease in the carbon:nitrogen ratio for corn leaves, deciduous tree leaves, soybeans, and the above six by-products occurred during a 3-month period of storage in water. Except for dried sugarcane stalks and tree leaves, all by-products attained C:N ratios less than 17:1. Sweet potato vines and trimmings may be fed directly to crayfish; rice stubble and rye hay, however, should be composted for a period of time to enhance their nutritive value through the process of microbial decomposition. Soybean stubble and dried sugarcane stalks do not appear suitable as sup...

Developing Consensus Indicators of Sustainability for Southeastern United States Aquaculture

Many diverse, conflicting stakeholders groups are activeley engaged in an increasingly volatile debate over the proper definition and application of sustainability in aquaculture. Attempts to find common-ground on general sustainability goals and parameters have not yet been successful. This study illustrates the potential of utilizing a Delphi approach to identify and refine consensus indicators of sustainability along three separate disciplinary axes; environmental, economic, and sociological. In fact, nonparametric statistical analysis of sustainability categories and indicators indicated a high level of consensus among and between diverse stakeholder groups after the Delphi process.

A Spermatology Study of Channel Catfish, Ictalurus punctatus

Abstract Forty m/ale channel catfish (Ictalurus punctatus) of two age groups and two stocks (domestic and wild) were compared in an experiment to study morphological and physiological characteristics of their testes and sperm cells from May through October. The gonosomatic index for 36 normal catfish examined averaged 0.25%. An average of 82.7% spermatozoa were alive with an average motility score of 2.96. These fish had an average gonadal sperm concentration of 7.1 X 109 spermatozoa per g wet testicular tissue. The testes were found to be composed of 2/3 spermatogenic and 1/3 glandular tissue. There were no morphological changes observed in the characteristics of the spermatogenic tissue during the period of study. The 3-year-old fish were consistently larger than the 2-year-olds, and the domestic fish were larger than the wild stock in each age group, which probably caused most of the differences in characteristics when comparisons were made.

Effects of Grass Carp on Freshwater Red Swamp Crawfish in Ponds

Abstract A study was conducted to determine effects of grass carp (Ctenopharyngodon idella) on red swamp crawfish (Procambarus clarkii) in ponds in Louisiana. Grass carp averaging 190 g each, stocked 4 fish per 0.01-hectare pond, significantly reduced the average yield (number and total weight) of harvestable size (⩾74 nm) crawfish. Stomach analysis of carp suggests that competition for food (plant matter) was the cause of lowered crawfish yields. After vegetation was depleted, the amounts of animal matter (mainly cladocerans, crawfish, and gyrinids) in grass carp stomachs increased greatly.