Feeding restriction, as a trigger for compensatory growth, might be considered an alternative viable strategy for minimizing waste as well as production costs. The study assessed whether juvenile redclaw crayfish Cherax quadricarinatus (initial weight 0.99 ± 0.03 g) was able to compensate for feeding restriction at different temperatures (23 ± 1, 27 ± 1 and 31 ± 1 ° C). Hyperphagia, food utiliz...

The effects of fasting on IGF-binding proteins (IGFBPs), glucose, and cortisol in channel catfish were examined. Fed fish (controls) were compared to 14-, 30-, and 45-day fasted fish and 45-day fasted fish refed for 15 additional days. Body length and weight changes, condition factor (CF), hepatosomatic index (HSI), and plasma glucose and cortisol were assessed to determine growth and metabolic...

Homologous recombinant tilapia growth hormone (rtGH) was tested for its effects on calcium metabolism in freshwater tilapia Oreochromis mossambicus . Fish were fed an optimal ration of 5% of their body mass per day. A positive correlation was found between the amount of food given and the branchial calcium influx. In male tilapia, the mean calcium influxes were 5.80 and 11.71 mmol h21 100 g21 w...

Previously, high concentrations of cadmium have been found in the hepatopancreas of the edible or brown crab (Cancer pagurus) sampled from positions north of about 67° N, compared to regions further south along the Norwegian coast, with no clear understanding why. In order to study a similar organism in the same ecosystem, the present study analyzed 210 shore crabs (Carcinus maenas) from four d...

Fecundity in several fish species is subject to down-regulation by atresia so if fecundity is estimated many months before spawning, this will be an overestimation of the realised fecundity (actual number of eggs spawned). In order to get accurate measurements of fecundity it is important to have knowledge on when potential fecundity (estimated fecundity at time of sampling) closely resembles t...

A 280-d study examined the effects of 17β-estradiol (E2) on reproduction and development of the sheepshead minnow (Cyprinodon variegatus) exposed from the parental (F0) through three subsequent (F1, F2, and F3) generations and evaluated the need for multigenerational assessments of the risks of endocrine-disrupting chemicals. This first three-generation study exposed adult F0 and F1 fish to mea...

The green alga Caulerpa racemosa var. cylindracea has invaded Mediterranean seabed including marine reserves, modifying the structure of habitats and altering the distributional patterns of associated organisms. However, the understanding of how such invasion can potentially affect functional properties of Mediterranean subtidal systems is yet to be determined. In this study, we show that C. ra...

Sanders, Kathryn E. M.S., Purdue University, May 2012. Relative Importance of Water Quality and Habitat to Fish Communities in Streams Influenced by Agricultural Land Use in the Cedar Creek Watershed, Indiana. Major Professor: Robert B. Gillespie. Agricultural land use has been shown to negatively impact fish communities in headwater streams that also serve as agricultural drainage ditches. The...

The reproductive cycle of the Australian sharpnose shark, Rhizoprionodon taylori, includes a temporary suspension of development at the commencement of embryogenesis termed embryonic diapause. This study investigated levels of 17β-estradiol (E2), testosterone (T) and progesterone (P4) in plasma samples of mature wild female R. taylori captured throughout the reproductive cycle and correlated th...

This study evaluated the suitability of flaxseed oil as a source of supplemental dietary lipid for fingerlings of rainbow trout (Oncorhynchus mykiss). Triplicate groups of the 30 fingerlings held under identical culture conditions were fed twice daily by iso-nitrogenous, iso-calorific and iso-lipidic diets for 8 weeks. Experimental diets consisted of 30.2% protein, 18.6 kJ g(-1) energy and 16.5...