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The widely used herbicide atrazine (ATR) may have endocrine-associated adverse effects, including on behavior. In this study, 120 adult freshwater mussels, Elliptio complanata, were exposed to ATR at the environmentally-relevant concentrations of 1.5, 15, or 150 μg/L. Burrowing depth was evaluated hourly for 6 hr and at sacrifice animals were sexed by gonad smear. Female controls burrowed overall approximately 30% less than males, the first report of sexual dimorphism in this behavior. Atrazine at 15 μg/L feminized burrowing in both sexes in that exposed animals burrowed 20% less than their same sex controls. Males treated with 1.5 μg /L ATR displayed approximately 20-fold higher vitellogenin (VTG) levels than same sex controls. Higher concentrations of ATR were not associated with increasing effects. A scatterplot showed a weak binomial curve associating low burrowing with high VTG levels. Taken together, these data suggest a non-linear dose-response in behavioral and physiological feminization produced by ATR and support the need to reconsider the widespread use of this compound.

Based on the construction principle of the already operative Closed Equilibrated Biological Aquatic System (C.E.B.A.S.) the concept of an aquaculture system for combined production of animal and plant biomass was developed. It consists of a tank for intensive fish culture which is equipped with a feeding lock representing also a trap for biomass removal followed by a water recycling system. This is an optimized version of the original C.E.B.A.S. filters adapted to higher water pollutions. It operates in a fully biological mode and is able to convert the high ammonia ion concentrations excreted by the fish gills into nitrite ions. The second biomass production site is a higher plant cultivator with an internal fiber optics light distributor which may utilize of solar energy. The selected water plant is a tropical rootless duckweed of the genus Wolffia which possesses a high capacity in nitrate elemination and is terrestrially cultured as a vegetable for human nutrition in Southeast Asia. It is produced in an improved suspension culture which allows the removal of excess biomass by tangential centrifugation. The plant cultivator is able to supply the whole system with oxygen for respiration and eliminates vice versa the carbon dioxide exhaled by the fish via photosynthesis. A gas exchanger may be used for emergency purposes or to deliver excess oxygen into the environment and may be implemented into the air regeneration system of a closed environment of higher order. The plant biomass is fed into a biomass processor which delivers condensed fresh and dried biomass as pellets. The recovered water is fed back into the aquaculture loop. The fresh plants can be used for human nutrition immediately or can be stored after sterilization in an adequate packing. The dried Wolffia pellets are collected and brought into the fish tank by an automated feeder. In parallel the water from the plant cultivator is driven back to the animal tank by a pump. The special feature of the system described is, however, the used fish species. It is the herbivorous teleost Ctenopharyngodon idellus (Chinese Grass Carp) which can be raised solely with plant biomass. In this case, moreover, it can be useful for the bioregeneration of plant biomass inedible for humans which can be used easily as additional food for the fishes thus resulting in an intensivation of animal protein production. The resupply of removed fish biomass has to be guarantueed by a separate hatchery.

Based on the experiences made with the Closed Equilibrated Biological Aquatic System (C.E.B.A.S.) which was primarily developed for long-term and multi-generation experiments with aquatic animals and plants in a space station highly effective fresh water recycling modules were elaborated utilizing a combination of ammonia oxidizing bacteria filters and higher plants. These exhibit a high effectivity to eliminate phosphate and anorganic nitrogen compounds and are, in addition, able to contribute to the oxygen supply of the aquatic animals. The C.E.B.A.S. filter system is able to keep a closed artificial aquatic ecosystem containing teleost fishes and water snails biologically stable for several month and to eliminate waste products deriving from degraded dead fishes without a decrease of the oxygen concentration down to less than 3.5 mg/l at 25 degrees C. More advanced C.E.B.A.S. filter systems, the BIOCURE filters, were also developed for utilization in semiintensive and intensive aquaculture systems for fishes. In fact such combined animal-plant aquaculture systems represent highly effective productions sites for human food if proper plant and fish species are selected. The present papers elucidates ways to novel aquaculture systems in which herbivorous fishes are raised by feeding them with plant biomass produced in the BIOCURE filters and presents the scheme of a modification which utilizes a plant species suitable also for human nutrition. Special attention is paid to the benefits of closed aquaculture system modules which may be integrated into bioregenerative life support systems of a higher complexity for, e.g., lunar or planetary bases including some psychological aspects of the introduction of animal protein production into plant-based life support systems. Moreover, the basic reproductive biological problems of aquatic animal breeding under reduced gravity are explained leading to a disposition of essential research programs in this context.

Population declines of horseshoe crabs (HSCs) have led to conflict regarding management strategies among commercial fishermen, biomedical companies, and environmentalists. These conflicts have also led to increased interest in HSC aquaculture. In this study, feeding trials were performed with juvenile HSCs to quantify dietary energy and protein requirements in order to optimize feed formulation and feeding regimes. Trials measured digestibility of two formulated dry feeds based on clam meat or fish meal. Juveniles were fed 3% of their body weight (BW), fecal matter was collected, and acid insoluble ash was used as a non-absorbed reference substance. Apparent digestibility of protein was found to be 93.2 and 90.8% and energy digestibility was 83.7 and 87.5% for the clam meal and fish meal feeds, respectively. Growth trials were conducted with juveniles (0.58–1.1 g) offering the two diets at increasing feeding levels in order to quantify their daily requirements for energy and protein. The results indicate HSCs would require 224 J of digestible energy and 8.7 mg of digestible protein for maintenance per day per gram body mass. The efficiency of utilization to deposit new growth above maintenance was relatively low and amounted to kDP = 0.11 and kDE = 0.13 for protein and energy, respectively.

Based on the construction principle of the Closed Equilibrated Biological Aquatic System (C.E.B.A.S.) two novel combined animal-plant production systems were developed in laboratory scale the first of which is dedicated to mid-term operation in closed state up to two years. In principle both consist of the “classic” C.E.B.A.S. subcomponents: animal tank (Zoological Component), plant cultivators (Botanical Component), ammonia converting bacteria filter (Microbial Component) and data acquisition/control unit (Electronical Component). The innovative approach in the first system is the utilization of minimally three aquatic plant cultivators for different species. In this one the animal tank has a volume of about 160 liters and is constructed as an “endless-way system” surronding a central unit containing the heat exchanger and the bacteria filter with volumes of about 1.5 liters each. A suspension plant cultivator (1 liter) for the edible duckweed Wolffia arrhiza is externally connected. The second plant cultivator is a meandric microalgal bioreactor for filamentous green algae. The third plant growth facilitiy is a chamber with about 2.5 liters volume for cultivation of the “traditional” C.E.B.A.S. plant species, the rootless buoyant Ceratophyllum demersum. Both latter units are illuminated with 9 W fluorescent lamps. In the current experiment the animal tank contains the live-bearing teleost fish Xiphophorus helleri and the small pulmonate water snailBiomphalaria glabrata because their physiological adaptation to the closed system conditions is well known from many previous C.E.B.A.S. experiments. The water temperature is maintained at 25 °C and the oxygen level is regulated between 4 and 7 mg/1 by switching on and off the plant cultivator illuminations according to a suitable pattern thus utilizing solely the oxygen produced by photosynthesis. The animals and the micoorganisms of filter and bioflim provide the plants with a sufficient amount of carbon dioxide. Oxygen concentration, pH value, temperature and redox potential are on-line recorded. Ion concentrations and numbers of living germs in the system water are determined twice monthly in the laboratory from samples taken from a special “sample removal module”; the sample volume is automatically replaced from an reservoir container. A rotatory pump produces a water flow of about 38 l/min. For a similar smaller test system with approx. 10 I volume developed from the C.E.B.A.S.-MINI-MODULE a novel indirect solar energy supply is tested which has a buffer capacity to maintain the system for 7 days in darkness under central European climate conditions also in winter. It contains only a single plant cultivator which is operated with Wollfla arrhiza. This lemnacean plant is able to produce large amounts of plant biomass in a short time by vegetative reproduction via daughter fronds. This easy-to-handle apparartus is dedicated to be operative more than 4 month. The experimental animals and microorganisms are the same as in the large system. The paper provides detailed information on the system construction principles and the biological, physical and chemical data of the initial phase of the test runs of both systems with the main focus on the large one.

Male summer flounder (Paralichthys dentatus) were given two injections (initially and 2 weeks later) of 17beta-estradiol (E2) totaling 0.2 (2 x 0.1), 2.0 (2 x 1.0) or 20.0 (2 x 10.0) mg E2/kg body weight. Blood and tissue samples were collected 4, 6 and 8 weeks after the initial injection in the (2 x 0.1) mg/kg treatment, 4, 6, 8, and 15 weeks after the first injection in the (2 x 1.0) mg/kg treatment and at 4 weeks only in the (2 x 10.0) mg/kg treatment. Five of the 12 fish injected twice with 10.0 mg/kg were moribund before the first sampling period. Circulating levels of vitellogenin (VTG) in the blood of all E2-injected fish from all treatments were comparable with those concentrations found in the blood of wild male carp (Cyprinus carpio) and walleye (Stezostedion vitreum) previously collected near a sewage treatment plant (0.1-10.0 mg VTG/ml plasma). Excessive hyalin material accumulated in the livers, kidneys and testes of the treated fish. A portion of that material was identified as VTG by immunohistochemistry. The accumulation of VTG, and possibly other estrogen-inducible proteins, resulted in hepatocyte hypertrophy, disruption of spermatogenesis, and obstruction or rupture of renal glomeruli.

Sediments are evaluated for toxicity by measuring mortality in a single cohort of amphipods in either acute (10-d) or chronic (28-d) bioassays. This investigation differed from conventional bioassays in four ways: Sublethal effects (fecundity) were estimated; the testing period was 60+ d; two successive generations were examined; and Elasmopus laevis Smith, 1873, amphipods were employed. Four test sediments were created between 58 and 424 microg/g of lead using the 30-microg/g whole-sediment as the control. Bioaccumulated lead at 60 d varied as a linear function of lead concentration in the sediments. Fecundity, as estimated by offspring-per-chamber and/or percent reproductive success, was reduced as sediment lead concentrations increased and reproduction was delayed compared with the control. The reduction in offspring production per test chamber varied significantly as an inverse function of lead sediment concentration, best described by a curvilinear exponential equation. It was concluded that E. laevis exposed to 118 microg/g and higher could not maintain a population as large as that in the control. Although the current sediment quality guideline for lead stipulates that adverse biological effects likely will occur above 218 microg/g, this study revealed a statistically significant negative reproductive response at 118 microg/g lead, and suggests that the current regulatory guideline for lead, based on lethality, should be reconsidered.

synopsis. With the exception ofthe agnathan fishes, a prolactin cell has been identified in all vertebrates in which it has been sought. This review examines the structure of the prolactin-producing pituitary cell in non-mammalian vertebrates, the manner in which it responds to natural and artificial stimuli, and its control by neural and humoral factors. Fundamental similarities and differences are described in an attempt to understand better its method of operation. Given our present state of knowledge, there is, among all the apparent diversity, a similarity in the basic structure and morphological response of this cell in teleosts, amphibi? ans, reptiles, and birds. One can identify and speak with relative certainty about a specific adenohypophysial cell called a "prolactin cell." More profound differences may be found at the level of control mechanisms, chemistry ofthe hormone(s), and the nature of receptivity and response of target tissues. It appears that although there are basic similarities in the design ofthe prolactin cell, the systems that control its activities may differ and the similar products produced by the cell may be used toward different ends. This review examines the structure of the prolactin-producing pituitary cell in nonmammalian vertebrates, the manner in which it responds to natural and artifically induced stimuli, and its relation to the

synopsis. The current state of our knowledge of the morphology and histo- and cytophysiology of the teleost pituitary gland is presented. The zonation that characterizes the adenohypophysis is based on the regional distribution of specific cell types. As a result there is also a functional zonation indicated by specific hormones emanating from clearly identifiable parts of the gland. These observations make the teleost hypophysis ideal for the study of problems that may be basic to all vertebrates. The ultrastructure of hypophysial cells is presented and related to observations at the light microscope level. The manner in which secretory granules are released from spe? cific cells is compared, and the problem of evaluating "cell activity" discussed. The application of immunohistochemical techniques to the study of the teleost pitui? tary gland is reviewed, and its use as a tool of investigation for future studies evaluated. These methods have helped to elucidate the cellular source of teleost pituitary hor? mones and have confirmed the findings of the histophysiologists.

A sex-linked gene controlling the age at which the gonadotrops of the pituitary gland differentiate has been discovered in Xiphophorus maculatus. Males homozygous for early differentiation become sexually mature between 10 and 16 weeks; those homozygous for late maturation between 22 and 40 weeks. Heterozygotes are intermediate. Since growth rate decreases when testes mature. the two classes of males differ significantly in adult size.