This study was designed to investigate the occurrence, severity, sources and causes of aquatic toxicity in a coastal river and estuary subject to non-point source pollutant inputs from adjacent agricultural and urban areas. The Pajaro River estuarine system on the central coast of California, USA, receives subsurface tile drain runoff from irrigated cropland, and seasonal surface runoff from agricultural, urban, industrial, and residential areas. Seven sites in the estuary, upstream river, tributary sloughs, and agricultural drainage ditches were selected to identify tributaries that might contribute toxic runoff to the estuary. These sites were each sampled 18 times over an 18-month period, and water samples were tested for toxicity to the mysid Neomysis mercedis, a resident crustacean. Results indicated toxicity in 78% of agricultural ditch samples, 25% of tributary slough samples, and 11% of river and estuary samples. Temporal patterns in the occurrence of toxicity indicated that agricultural ditches and upper river were more important than the freshwater sloughs as sources of toxic runoff to the estuary. Chemical analyses were conducted on samples collected at each site on two occasions. Organophosphate pesticides were detected in samples collected when the river flow rate was low, and persistent hydrophobic organochlorine pesticides were detected after high surface runoff. Three pesticides (toxaphene, DDT, and diazinon) were found at concentrations higher than published toxicity thresholds for resident aquatic species. Toxicity in the estuary was significantly correlated with increased river flow. Chemical causes of toxicity were investigated in two preliminary and four full Phase I Toxicity Identification Evaluations (TIEs ) on six separate samples from the agricultural drainage ditches receiving tile drain discharges. The TIE results indicated that multiple compounds were responsible for toxicity in all samples evaluated, and that non-polar and perhaps polar organic compounds were present in toxic concentrations.

1.1. The dynamics of ovarian development in Leptocottus armatus were studied. Seasonal changes of serum estradiol-17β, serum vitellogenin, serum total lipids and visceral lipid reserves were monitored.2.2. Two to four distinct size classes (clutches) of oocytes occurred in the ovary preceding and during the spawning period. One of these clutches contained oocytes in the vitellogenic or post-vitellogenic phase, a second clutch contained oocytes “arrested” in the cortical alveoli stage and a third clutch contained non-yolky oocytes. Only one clutch was oviposited in the annual spawning season.3.3. Estradiol levels increased coincident with the appearance of yolky oocytes in the ovary. Serum estrogen levels were highest during the period of ovulation and spawning. During the spawning period estradiol titers were not significantly correlated with oocyte size or gonosomatic index.4.4. Serum vitellogenin levels increased in parallel with oocyte size and estradiol titers. Vitellogenin levels were relatively low during the early portion of the spawning period, becoming elevated again towards the end of the spawning period. In concordance with ovarian regression, serum vitellogenin levels declined and remained low during the ovarian quiescence phase. Neither GSI nor serum estradiol titers correlated significantly with vitellogenin levels.5.5. With initiation of ovarian recrudescence visceral lipid reserves began to decline and continued to decline through the vitellogenic and spawning phases. Visceral lipid reserves were inversely correlated with ovarian GSI. Serum lipid levels were high during ovarian recrudescence, remaining elevated through the spawning period. During the phase of ovarian quiescence serum lipid levels were low and visceral lipid reserves were high. Visceral lipid reserves showed an inverse correlation to serum estradiol titers.

The reproductive condition of female Oligocottus snyderi Greeley during 18+ months at Dillon Beach, California was examined. Seasonal differences in reproductive condition were identified by diameter measurements of ovarian follicles in pre‐vitellogenic, cortical alveoli and vitellogenic stages of development which showed that female O. snyderi appeared capable of reproduction during 6 to 8 months of the year. Reproduction occurred from late autumn to early spring and it is likely that females reproduce more than once a year. Follicular development within the population was asynchronous; development within individual females was group synchronous. The percentage of females with vitellogenic follicles in each collection was negatively correlated with photoperiod and productivity and positively correlated with wave action. Conversely, the percentage of newly recruited individuals in each sample was positively correlated with photoperiod and productivity. It appears that reproduction and recruitment in O. snyderi are significantly influenced by annual productivity cycles; daylength changes may provide an anticipatory cue for the productivity cycle.

1.1. Embryos of the viviparous embiotocid fishes develop free within the ovarian cavity from small eggs for approximately 6 months. The biochemical composition of ovarian fluid was determined and compared to serum constituents in three embiotocid species during the gestation phase.2.2. SDS-gel electrophoresis data showed that ovarian fluid collected from female Cymatogaster aggregata during late gestation was essentially devoid of serum peptides, but contained peptides absent from maternal serum. The ovarian fluid peptides are probably derived from the ovarian epithelial lining.3.3. Pregnant female ovarian fluid contained large quantities of urea, whereas the maternal serum was devoid of this metabolite. This suggests that embiotocid embryos, but not adults, produce urea as a nitrogenous waste: furthermore, ovarian membranes must be relatively impermeable to urea.4.4. Amino acids in the ovarian fluid of Cymatogaster basically correspond to those in maternal serum. but were, in most cases, at lower levels. Although absent from serum, phosphoethanolamine was present at high levels in the ovarian fluid of pregnant Cymatogaster, but not Hyslerocarpus Irciski, during late gestation.5.5. The principal amino compound, exclusive of urea, in the ovarian fluid of Hysterocarpus and Micrometrus minimus was taurine. Serum levels of glutamine, ethanolamine and taurine were elevated in pregnant embiotocids.6.6. Lipid levels were also elevated in maternal serum during late pregnancy. Precluding phospholipids, the concentration of lipids in ovarian fluids was considerably lower than in maternal serum.7.7. In Cymatngtisler and Hysterocarpus serum progesterone and estradiol levels were comparatively low during gestation, posing some doubt as to the significance of these steroids in maintenance of pregnancy.8.8. The possibility that embiotocids produce an estrogen-dependent, vitellogenin-like protein was examined. Studies with Cymatogaster and Hysterocarpus indicated that the embiotocids may be the only teleostean family yet known which do not produce a vitellogenin-like protein.

1.1. Using data collected from two teleostean fish species the assumptions of the gonosomatic index (GSI) were examined primarily by regression analysis and analysis of covariance.2.2. Standard length of the fish and standard length cubed can have a higher degree of correlation with ovarian weight as compared to body weight. Therefore, an ovarian weight-body weight ratio is not always the best way of expressing a gonadal index.3.3. When ovarian weight is regressed on some expression of body size, intercepts of the regression equations have a non-zero intercept. Furthermore, intercepts of regression equations from fish in different ovarian development stages are not always statistically homogenous. These findings are inconsistent with the GSI assumption of a zero intercept.4.4. The relationship of ovarian weight to body size changes with the stage of oocyte development. Thus, the GSI is an inaccurate means of comparing gonadal activity between experimental groups.5.5. When independent and dependent variables are subjected to log transformations, the relationship of ovarian weight to body size is less likely to vary with stage of oocyte development. Thus, expressing ovarian weight as an exponential function of some measure of body size may provide a more appropriate gonadal index.6.6. The analyses presented disclose that the GSI is not an accurate indicator of gonadal activity.

The tryptophan hydroxylase inhibitor para-chlorophenylalanine (pCPA) was employed in an investigation of the role of brain serotonin in the regulation of pituitary cyclic AMP levels in Salmo gairdneri. Hypothalamic serotonin content was measured with a fluorometric assay, while pituitary cAMP was determined by means of a double-antibody radioimmunoassay. A time-course study revealed that 250 mg pCPA/kg significantly reduced hypothalamic serotonin content within 1 hr after injection. Lower doses were effective in reducing serotonin content after 48 hr. Pituitary cAMP levels declined significantly 1 hr after injection of 250 mg pCPA/kg. Administration of pCPA at 50 and 250 mg/kg doses reduced cAMP levels within 24 hr. These data indicate that a serotonergic mechanism is involved with the regulation of pituitary cyclic AMP levels in the rainbow trout.

The effects of exposure to various photoregimes or to constant darkness on liver glycogen and plasma glucose levels in the goldfish were examined during different seasons. In addition, pinealectomized fish and optic nerve sectioned fish were exposed to the photoregimes to assess the potential role of the pineal organ and retinal pathways in mediating photoperiod effects. Neither photoperiod manipulation nor exposure to constant darkness affected liver glycogen levels in experiments conducted during October and January. Photoperiod alteration and exposure to constant darkness resulted in changes of liver glycogen and plasma glucose levels during May, suggesting that response to photoperiod varies with season. Likewise, optic nerve sectioning altered liver glycogen levels during May, but not during October or January, indicating that retinal pathways may be involved in mediating photoperiod effects. During both October and May pinealectomy resulted in a lowering of liver glycogen levels independent of photoregime ; the extent to which hepatic glycogen levels were decreased by pinealectomy was affected by lighting conditions. Plasma glucose levels were elevated in pinealectomized fish regardless of photoregime during May ; the degree of this increase varied with lighting conditions. Our data suggest that the pineal organ does not mediate photoperiod effects on plasma glucose and hepatic glycogen levels, but that there is a functional relationship between this organ and carbohydrate metabolism.

1. The effects of photoperiod acclimation, pinealectomy, and sampling time on monoamine oxidase (MAO) activity in the basal medial lobe of the goldfish (Carassius auratus) hypothalamus were examined.

The effects of pinealectomy, optic tract section, or exposure to continuous darkness on serum estradiol-17β levels in the goldfish were examined during the spring and fall. Pineal removal had no effect on serum estrogen levels or GSI in either fall or spring. Optic tract section decreased serum estrogen levels in both spring and fall experiments. Ovarian regression was initiated in fish exposed to continuous darkness and optic tract-sectioned fish during the spring, but fish maintained in darkness exhibited no change in serum estrogen levels. Our data imply that it is primarily retinal pathways which mediate the effects of increasing daylength on goldfish ovarian development during the spring.

The effects of surgical removal of the pineal organ on gonadal activity in the goldfish exposed to short or long photoperiod regimes were examined at different times of the year. From late winter to early summer, pinealectomy had a pronounced effect on gonadal activity. During this period, pinealectomy retarded gonadal activity in fish maintained on long photoperiods, but stimulated reproductive function in animals exposed to short photoperiods. Pinealectomy had no obvious effects on reproductive function from late summer to early winter. Our data suggest that the pineal organ of goldfish can be anti- or progonadal during certain seasons, depending on daylength conditions.

Goldfish subjected to increased temperatures at one of six different times of day had significant differences in weight gain and testicular growth depending on the time of treatment. Depending on the time of day the thermocycle was initiated, weight gain and testicular growth could be either stimulated, inhibited, or equal to that in fishes subjected to constant heat or constant cold. Heat applied during the last 4 h of darkness was particularly conducive to weight gain and testicular growth. The results of this study may have important implications for aquaculture.