Broodstock of Gulf killifish Fundulus grandis (initial mean [6SD] weight ¼ 8.2 6 1.6 g) were held in static outdoor tanks at a 2:1 (female : male) sex ratio and at densities of 15, 30, or 45 fish/m 3 . Eggs were collected twice per week from spawning mats suspended 8 cm below the water surface. Collected eggs were measured volumetrically and assessed for total number, egg size, and embryo viability. Significantly more eggs were collected from tanks with manufactured (Spawntex) spawning mats than from tanks with cured Spanish moss spawning mats. Significant differences in the mean number of eggs collected were present among density treatments in April, June, and July. Stocking density was also associated with mortality; the greatest mortality was observed in tanks at the highest density (45 fish/m 3 ). There was a clear pattern in egg production in relation to lunar phase, with egg production peaks occurring between full and new moon phases for all three stocking densities. Mean gonadosomatic index values differed significantly among sampling months for both females and males. Analysis of ovaries via histological sections indicated trends in oocyte stages that correlated to continued egg production for this fractionally spawning species. Peak egg production occurred between April and mid-May, when mean (6SD) weekly water temperatures ranged from 23.8 6 1.78C to 28.2 6 1.28C. During April, the mean daily number of eggs collected translated to a reproductive output of approximately 0.90, 0.72, and 0.76 eggs/g of female for stocking densities of 15, 30, and 45 fish/m 3 , respectively. Based on egg output and mortality over the 5-month spawning period, the intermediate density (30 fish/m 3 ) appeared to provide the optimum number of eggs per individual over time for Gulf killifish broodstock held in static outdoor tanks at a 2:1 female : male sex ratio.

A 34‐day study was conducted to estimate the effect of stocking density on growth, biomass, and yield of harvestable animals in red swamp crawfish, Procambarus clarkii (Girard). Juvenile crawfish were stocked at l, 2, 4, 8, and 16 crawfish per m2 into plastic‐lined metal pools planted with rice (Oryza sativa) with three replicate pools at each density. Crawfish averaged 35 ± 1.5 mm (SE) total length at the time of stocking.Growth in total length and weight was significantly affected by density (P < 0.01), ranging from 91.5 mm and 20.7 g for crawfish stocked at 1 per m2 to 62.5 mm and 6.3 g for crawfish stocked at 16 per m2. The total crawfish biomass ranged from 20.7 g per m2 for crawfish stocked at 1 per m2 to 88.7 g per m2 at 16 per m2. The portion of that biomass made up of harvestable sized animals (>75 mm total length) ranged from 100% at 1 per m2 to 0.7% at 16 per m2. Gross revenues per ha were projected for crawfish yields at each stocking density with and without a graded product.

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Abstract.— Channel catfish Ictalurus punctatus fry are typically held under hatchery conditions for 7 to 14 d after hatching to allow feeding and growth before they are stocked into nursery ponds to produce fingerling catfish. In an attempt to reduce hatchery operating costs, several catfish fingerling producers in Louisiana presently stock fry within 2 d after hatching before yolk absorption is complete. Fry at this stage of development are commonly referred to as “sac‐fry.” Although research has shown that fry can be stocked at the onset of yolk absorption with no detrimental effects on subsequent fingerling production, stocking sac‐fry has been reported to result in reduced fingerling survival. To further investigate this topic, production trials were conducted in experimental outdoor pools over the course of two growing seasons to evaluate the effect of stocking fry of three different ages (2‐, 7‐, and 14‐d post‐hatch, DPH) on survival, growth (weight and length), condition factor (K), yield, feed consumption, and feed conversion ratio (FCR) of fingerling catfish. Results from both trials indicated that the age at which fry were stocked had no effect on production characteristics with the exception of growth. Specifically, fingerlings reared from fry stocked at 2 and 7 DPH were significantly larger than fingerlings reared from fry stocked at an age of 14 DPH. These findings suggest that the practice of stocking sac‐fry may be a suitable alternative to the traditional procedure of holding and feeding fry under hatchery conditions prior to stocking. However, in order to fully evaluate the effects of early‐age stocking of catfish fry on fingerling production, additional studies must be conducted under pond conditions. Furthermore, these studies must be coupled with a rigorous economic analysis before the practice of stocking sac‐fry can be recommended to the catfish industry.