Robert R. Stickney

Effects of Dietary Lipid Quality on Growth and Food Conversion of Tilapia

Growth and food conversion patterns of Tilapia aurea raised in aquaria and fed diets containing 10% lipid from 4 different sources showed that growth and food conversion were significantly better on menhaden oil than on beef tallow. No significant differences were detected in growth of tilapia on catfish oil or soybean oil and either beef tallow or menhaden oil. No mortalities occurred during the course of the lO-week feeding trial. T. aurea responded similarly to channel catfish with respect to their ability to utilize menhaden oil as a suitable source of dietary lipid. Tilapia did not...


Growth of Tilapia Aurea as a Function of Degree of Dietary Lipid Saturation

Tilapia aurea fingerlings were fed semipurified diets differing only in the degree of saturation in the lipid component (soybean oil). Growth improved significantly as degree of unsaturation in dietary lipid increased. All fish became depleted in high (> 18 carbon atom) molecular weight polyunsaturated fatty acids during the course of the study. This may indicate that desaturation and elongation of such dietary fatty acids as linoleic and linolenic acid either did not occur or was so slow that such fatty acids as 20:5n-3, 22:5n-3 and 22:6n-3 were metabolized before appearing in the...


Culture Of Chinese Waterchestnuts In The Southeastern United States

Two .05 ha ponds were planted with water chestnut (Eleocharis dulcis) corms in March 1978. After the waterchestnuts had sprouted the ponds were flooded in late March to an average depth of 15 em, and remained flooded until mid-October 1978. The ponds were drained and left dry until February 1979 when they were harvested. One pond had excellent production throughout, leading to an extrapolated level of 13,600 kg! ha. The other pond had good production only along the sides and in the shallow end due to high turbidity and unfavorably low soil pH. Production in the second pond was at the rate...


Food Habits Of Fishes Associated With Marshland Developed On Dredged Material

The food habits of Micropogon undulatus, Leiostomus xanthurus, Fundulus similis. Cyprinodon variegatus. Menidia beryllina and Membras martinica were studied in conjunction with the development of a man-made salt marsh planted during 1976 on Bolivar Peninsula, Galveston Bay, TX. Each of the fishes studied fed to a considerable extent on the benthos community, and utilized at least some zooplanktonic and terrestrial insect foods. The dominant food organisms in the fish stomachs examined corresponded, in general, with those previously reported by other investigators. The artificially created...


Algae-Fed Brine Shrimp Nauplii As A Food Source For Larval Spotted Seatrout

Larval spotted seatrout (Cymoscion nebulosus) grew faster on 1 and 2 day prefed brine shrimp (Artemia salina) nauplii than fish fed newly-hatched nauplii. Fish growth and survival were reduced when 3 and 4 day pref.ed, as compared with newlyhatched nauplii were offered. Proximate analysis and calorimetry demonstrated the occurrence of a temporal decline in the nutritional value of both fed and unfed brine shrimp nauplii. At the relatively low levels of algal cell concentration available for prefeeding brine shrimp, this study indicates that I day old unfed nauplii are nutritionally equal...


Cellulase Activity in the Stomachs of Freshwater Fishes from Texas

The occurrence of cellulase enzyme activity was examined in the stomachs of Texas fishes representing 26 species. Comparison ofthe results obtained from enzyme studies with food habits indicated that the two were independent. A hypothesis that the presence of certain enzymes might be correlated with black peritoneum in fish (McAllister 1959) must be rejected with regard to cellulase based on the results of this study. Unlike a previous study (Stickney and Shumway 1974) in which cellulase activity within species was always either present or absent, seven species examined during the present...


Mercury Concentration In Various Tissues Of The Bottlenose Dolphin (Tursiops Truncatus)

The mercury concentrations in various tissues of an adult bottlenose dolphin, Tursiops truncatus, were determined by nameless atomic absorption spectrophotometry. Mercury was concentrated in the kidneys and liver at levels in excess of 18 parts per million (dry weight basis). One sample from the right lobe of the liver contained 34.5 ppm mercury. With the exception of skin and subcutaneous tissue, a sample from the medulla oblongata and a bone sample (skull fragment), all samples run exceeded 1.0 ppm mercury. Studies as to the prevalence of high mercury levels in Tursiops truncatus and...