Fred S. Conte

Effect of feeding rate and water temperature on growth of juvenile white sturgeon (Acipenser transmontanus)

Abstract A 2×4 factorial experiment was conducted for 8 weeks to determine the effect of feeding rate and water temperature on the growth performance of 30-g-size white sturgeon. Body weight increase (BWI) and feed efficiency (FE) were significantly (P

Dietary effects on tissue composition, oogenesis and the reproductive performance of female rainbow trout (Oncorhynchus mykiss).

Washburn, B.S., Frye, D.J., Hung, S.S.O., Doroshov, S.I. and Conte, F.S., 1990. Dietary effects on tissue composition, oogenesis and the reproductive performance of female rainbow trout (Oncorhynchus mykiss). Aquaculture, 90: 179-195. One hundred and eighty 2-year-old female rainbow trout brood&h were fed a low protein, high carbohydrate (LP), intermediate protein and carbohydrate (IP), or a high protein, low carbohydrate (HP) diet for 9 months to determine the effect of the diets on ovarian development, body proximate composition, and reproductive performance. Dietary treatment did not have any effect on the histomorphology of ovarian development. However, during vitellogenesis (July until November), fish fed different diets had significantly different body and carcass weights, plasma glucose, and plasma vitellogenin levels. Although there were some differences between the three treatments in the proximate composition of gonads, liver, and gastrointestinal tract during the reproductive cycle, no consistent pattern was seen. At spawning, LP fish retained a higher amount of lipid in the ovaries and gastrointestinal tract than the other two groups. Although the egg proximate composition was the same regardless of diet, eggs from fish fed the LP and IP diets had significantly higher survival (P-z 0.05 ) to the eye-up stage, hatchability, and relative fecundity than HP fish.

Growth and feed efficiency of white sturgeon (Acipenser transmontanus) sub-yearlings at different feeding rates

Eight groups of 30 white sturgeon with an average individual weight of 0.25 kg were fed at four different rates in a Latin square experiment for four 2-week periods. The four feeding rates (FR) were 0.5, 1.0, 1.5 and 2.0% of the total body weight per day (BW/day) of fish in a tank, and rations were corrected daily for expected growth. The experiment was conducted with two randomized blocks, and the feeding rates were changed within each block at the beginning of each subsequent period. The mean percent body weight increases (%BWI) for the four periods at the different feeding rates were: 3.6% (FR = 0.5%), 13.6% (FR = 1.0%), 22.3% (FR = 1.5%), and 27.1% (FR = 2.0%); where the corresponding values of feed efficiency (FE) were 0.54, 0.99, 1.04, and 0.92, respectively. The mean %BWI were significantly (P < 0.05) different betwen the four feeding rates, but only the mean FE obtained from sturgeon fed 0.5% BW/day was significantly different from the others. Neither initial body weight nor feeding period had a significant effect on the %BWI or FE, and no significant interactions were seen. The results suggest an optimal feeding rate between 1.5 and 2.0% BW/day for white sturgeon between 0.25 and 0.5 kg at 18° C.

Effects of feeding rates on growth, body composition and nutrient metabolism in striped bass (Morone saxatilis) fingerlings

Abstract A 12-week experiment was conducted to determine the effects of feeding rates on growth, morphology, body composition, and nutrient partitioning and metabolism in striped bass fingerlings with an average initial body weight of 38 g. The striped bass fingerlings were fed a commercial salmonid feed at different feeding rates from 0.5 to 4.0% (with 0.5% increments) of body weight per day (BW/day) at 19°C. The feed was dispensed continuously using automatic feeders and each feeding rate was administered in triplicate to groups of 15 striped bass fingerlings. Growth rate as measured by the percent body weight increase was significantly (P

Economic impact of paralytic shellfish poison on the oyster industry in the Pacific United States

Abstract The oyster industry on the west coast of the continental United States extends from Morro Bay, California, north to and including Puget Sound, Washington. Periodic outbreaks of paralytic shellfish poison caused by dinoflagellates of the genus Gonyaulax have resulted in reported symptoms and even death from consumption of contaminated shellfish. Although no deaths and only two reported outbreaks have affected commercial oysters, the fear of paralytic shellfish poison results in seasonal depressions in oyster markets, even when outbreaks are not present. This, coupled with inaccurate or misleading information distributed to the public, not only affects marketing of oysters under normal circumstances, but also has an impact on the interstate shipment of nonaffected, Health Service-approved oysters from nonaffected areas. Because of the nature of the west coast industry, both in terms of investment for acquisition of seed and cost of structures used in grow-out techniques, interruptions in the marketing of oysters have a drastic impact on the oyster industry. This study reviews the economic impact of paralytic shellfish poisoning, the factors that increase the impact beyond the normal response, and requirements necessary to lessen the impact on the oyster industry.

Survival, Growth, and Body Composition of White Sturgeon Larvae Fed Purified and Commercial Diets at 14.7 and 18.4°C

Abstract Forty groups of 9-d-old (posthatch) larval white sturgeon (Acipenser transmontanus) were kept at either 14.7 or 18.4°C and fed one of five different diets: three commercial semimoist starter diets for salmonids and two dry purified diets for juvenile white sturgeons. Among fish fed the semimoist commercial diets, overall survival was higher (62–79%) at 14.7°C than at 18.4°C (24–45%). White sturgeons fed the purified diets achieved survival rates of 4–19% and 15–33% at 14.7 and 18.4°C, respectively. Growth was uniformly greater in the warmer water. Fish fed the commercial diets achieved a final average total weight (all surviving fish in a tank) of at least twice that of fish fed the purified diets. Whole-body moisture content was higher in fish reared at the lower temperature for each diet, as was percent protein in fish fed each of the diets except the medicated semimoist commercial ration. Body lipid did not vary between sturgeon larvae reared at the two temperatures, whereas ash levels were gr...

Identification of the Origin and Localization of Chorion (Egg Envelope) Proteins in an Ancient Fish, the White Sturgeon, Acipenser transmontanus

ABSTRACT In many modern teleost fish, chorion (egg envelope) glycoproteins are synthesized in the liver of females, and the expression of those genes is controlled by endogenous estrogen released from the ovary during maturation. However, among the classical teleosts, such as salmonid, carp, and zebrafish, the chorion glycoproteins are synthesized in the oocyte, as in higher vertebrates. Sturgeon, which are members of the subclass Chondrostei, represent an ancient lineage of ray-finned fishes that differ from other teleosts in that their sperm possess acrosomes, their eggs have numerous micropyles, and early embryo development is similar to that of amphibians. In order to understand the molecular mechanisms of chorion formation and the phylogenetic relationship between sturgeon and other teleosts, we used specific antibodies directed against the primary components of sturgeon chorion glycoproteins, using immunoblotting and immunocytochemistry approaches. The origin of each chorion glycoprotein was determined through analyses of both liver and ovary, and their localization during ovarian development was investigated. Our data indicate that the origin of the major chorion glycoproteins of sturgeon, ChG1, ChG2, and ChG4, derive not only from the oocyte itself but also from follicle cells in the ovary, as well as from hepatocytes. In the follicle cell layer, granulosa cells were found to be the primary source of ChGs during oogenesis in white sturgeon. The unique origins of chorion glycoproteins in sturgeon suggest that sturgeons are an intermediate form in the evolution of the teleost lineage.

Carcass proximate composition of juvenile white sturgeon (acipenser transmontanus)

Abstract 1. 1. Body wt, carcass wt, liver wt, gonad wt, total length, and carcass proximate compositions of 8- to 32-month-old cultured sturgeon were significantly affected ( P 2. 2. Correlation coefficients were significant between age and body wt ( r = 0.96), carcass wt ( r = 0.96), total length ( r = 0.92), liver wt ( r = 0.88), gonad wt ( r = 0.76), gonadosomatic index ( r = 0.52), carcass moisture ( r = −0.93), crude protein ( r = 0.62) and lipid ( r = 0.57). 3. 3. The carcass proximate compositions of cultured sturgeon were 72.1–79.4% moisture, 13.5–17.5% crude protein, 3.4–7.4% crude lipid, and 4.2–5.0% ash. 4. 4. A high variability in the body measurements and carcass proximate compositions of some cultured sturgeon suggested high potential for genetic and nutrition improvements in culturing these fish in hatcheries.

AQUARIUS: A Decision Support System for Aquaculture

The United States shellfish industry is regulated under the National Shellfish Sanitation Program, administered federally by the U.S Food and Drug Administration, and at the state level by departments of health or agriculture. Shellfish authorities are empowered to close shellfish harvest if water quality drops below food safety levels. Because monitoring for all human pathogens in growing areas is not feasible, fecal coliform bacteria are used as indicator organisms for the potential presence of pathogens from fecal contamination. Every decade, sanitary surveys are conducted during adverse pollution conditions to establish equations and rules for conditionally approved growing areas to predict rainfall levels when fecal coliform levels might exceed the “NSSP 14/43” safety standard. Modifying these rules requires an extensive sampling programs and analyses. As watersheds change, there is pressure to reclassify growing sites and to modify closure rules. The AQUARIUS program is the first tool developed to directly evaluate closure rules for the shellfish industry, and to perform a series of “what-if” scenarios for selected variables. AQUARIUS uses the actual rainfall data to simulate the open/close status of a given growing site for any length of time under two closure rules: one the current rule and the other proposed new rule. AQUARIUS then uses the actual fecal coliform data from the site to compare the fecal coliform level of “site open under current rule” versus “site open under new rule. Based on the results of SSP 14/43” standards and T-Tests, the new closure rule is either accepted or rejected.