Lyndal L. Johnson

Patterns of oocyte development and related changes in plasma 17-β estradiol, vitellogenin, and plasma chemistry in English sole Parophrys vetulus Girard

Abstract Ovarian development was monitored in female English sole Parophrys vetulus Girard from three sites in Puget Sound: Sinclair Inlet and Port Susan, where fish are normally resident, and University Point, a known spawning area for English sole. Histological changes in ovary and liver as well as changes in plasma estradiol and vitellogenin levels, gonadosomatic index, hepatosomatic index, and calcium, phosphate, magnesium, glucose, triglyceridesm total protein, and albumin concentrations in the plasma over the reproductive cycle were assessed. Vitellogenesis in female English sole began in the early fall, and swapping activity reached its peak in February. Oocyte development was group synchronous with two distinct clutches of oocytes in the maturing ovary. In general, the cytological and physiological changes which English sole underwent during the reproductive cycle were similar to those observed in other teleost species. However, certain distinctive features were observed, including a high prevalence of atresia of nonyolked oocytes.

Survey of Pathogens in Juvenile Salmon Oncorhynchus Spp. Migrating through Pacific Northwest Estuaries

Abstract Although the adverse impact of pathogens on salmon populations in the Pacific Northwest is often discussed and recognized, little is currently known regarding the incidence and corresponding significance of delayed disease-induced mortalities. In the study reported herein, we surveyed the presence and prevalence of selected micro- and macroparasites in out-migrant juvenile coho salmon Oncorhynchus kisutch and Chinook salmon O. tshawytscha from 12 coastal estuaries in the Pacific Northwest over a 6-year period (1996–2001). The major finding of this study was the widespread occurrence of pathogens in wild salmon from Pacific Northwest estuaries. The six most prevalent pathogens infecting both juvenile Chinook and coho salmon were Renibacterium salmoninarum, Nanophyetus salmincola, an erythrocytic cytoplasmic virus (erythrocytic inclusion body syndrome or erythrocytic necrosis virus), and three gram-negative bacteria (Listonella anguillarum, Yersinia ruckeri, and Aeromonas salmonicida). The most pre...

Contaminant effects on reproductive success in selected benthic fish

Abstract Field studies on ovarian development in English sole from urban and nonurban sites in Puget Sound, Washington, USA, demonstrated that animals with elevated levels of fluorescent aromatic compounds (FACs) in bile were less likely to enter vitellogenesis and had lower plasma concentrations of estradiol than female sole with low levels of contaminant exposure. Biliary FACs were positively correlated with hepatic P450 activity, which was also elevated in sole showing inhibited ovarian development. These findings suggest that contaminant exposure may disrupt vitellogenesis in female fish. Results of the field study were supported by laboratory experiments showing that pretreatment of gravid female English sole with extracts of contaminated sediment decreased levels of endogenous estradiol. A similar response was observed in rock sole and flathead sole treated with Prudhoe Bay crude oil. However, exposure of English sole to sediment extracts had little effect on the activity of hepatic-steroid-metabolizing enzymes, indicating that some mechanism other than enhanced steroid metabolism may be responsible for reductions in endogenous circulating-steroid levels. Our recent studies suggest that reductions in endogenous estradiol levels may result from depressed ovarian steroidogenesis, as contaminant-associated reductions in in-vitro ovarian estradiol production were observed in English sole, rock sole, and flathead sole. Preliminary studies on winter flounder and white croaker indicate that they may also experience reproductive impairment as a result of exposure to contaminants, but the phase of the reproductive cycle that is most severely impacted varies from species to species.

A comprehensive assessment of the impacts of contaminants on fish from an urban waterway

Abstract The Hylebos Waterway, in central Puget Sound in the state of Washington, is severely contaminated by a variety of organic and inorganic contaminants. Studies in the 1970s had shown that flatfish residing in the Hylebos Waterway had increased prevalences of several types of toxicopathic liver disease, including neoplasms. In 1994, studies were initiated to: (i) determine if contaminant source control had resulted in improvements in habitat quality, as determined by prevalences of liver disease in flatfish; (ii) encompass the assessment of reproductive function in flatfish; and (iii) determine whether and to what degree there might be contaminant exposure of juvenile salmonids which migrate through this waterway. The findings show that there have been no appreciable changes in disease prevalences or apparent contaminant exposure of flatfish from this site since the 1970s. Moreover, female flatfish from the Hylebos Waterway are showing evidence of precocious sexual maturation in young animals, and inhibited gonadal development in older fish. The results also showed that two species of juvenile salmon sampled from this site are being exposed to a wide range of chemical contaminants, and the levels of exposure are comparable to levels which have previously been shown to cause impaired growth, immunosuppression, and increased mortality following pathogen exposure. These studies, which were done to provide a scientific and legal basis for cleaning up and restoring this degraded habitat, provide an example of how studies of pollutant responses in marine organisms (PRIMO) are being applied to societal and resource manager needs.

Reproductive injury in English Sole (Pleuronectes vetulus) from the Hylebos Waterway, Commencement Bay, Washington

The effect of exposure to xenobiotic compounds on ovarian development was investigated in prespawning female English sole (Pleuronectes vetulus) from the Hylebos Waterway, an industrial site in Commencement Bay, WA, contaminated with aromatic hydrocarbons (AHs), polychlorinated biphenyls (PCBs)and other chlorinated compounds, including hexachlorobutadiene (HCBD) and hexachlorobenzene (HCB). Reference sole were collected from Colvos Passage, a nearby site with minimal sediment contaminant concentrations. English sole from theHylebos Waterway had significantly higher concentrations of fluorescent aromatic compounds (FACs) in bile, polycyclic aromatic compound-DNA adducts in liver, and dioxin-like and other selected PCB congeners in liver than sole from Colvos Passage. The Hylebos Waterway animals also showed significant alterations in their pattern of reproductive development when compared to Colvos Passage sole. Hylebos Waterway sole entered vitellogenesis at a nearlier age than Colvos Passage sole, with about 50%of fish below 5 years of age maturing in the Hylebos Waterway as compared to 20% of Colvos Passage sole in this age range, with corresponding increases in plasma estradiol concentrations and GSI in Hylebosfish. However, while the proportion of maturing Colvos Passage females increased with age to over70% for fish 5 years of age or greater, the proportion of maturing females in the Hylebos Waterway remained at about 50%. Moreover, plasma estradiol concentrations and gonadosomatic indices in these sole were depressed. Inhibited reproductive development and increased oocyte atresia in adult fish were correlated with elevated concentrations of FACs in bile. Enhanced growth, as well as exposure to both aromatic and chlorinated hydrocarbons, were associated with precocious maturation in sub adult Hylebos Waterway sole.

Polybrominated Diphenyl Ethers in Outmigrant Juvenile Chinook Salmon from the Lower Columbia River and Estuary and Puget Sound, Washington

Previous studies have examined the presence, distribution, and concentrations of toxic contaminants in two major waterways in the Pacific Northwest: the lower Columbia River and Estuary (LCR&E) and Puget Sound, Washington. However, those studies have not reported on the levels of polybrominated diphenyl ethers (PBDEs) in juvenile Chinook salmon (Onchorynchus tshawytscha). Populations of Chinook salmon from the LCR&E and Puget Sound are declining, and some stocks are currently listed as “threatened” under the Endangered Species Act. Bioaccumulation of contaminants, including PBDEs, by juvenile Chinook salmon in the LCR&E and Puget Sound is of concern due to the potential toxicity of the contaminants and associated sublethal effects in fish. In this article, we present the concentrations of PBDEs measured in gutted bodies and stomach contents of outmigrant juvenile Chinook salmon collected at six sites in the LCR&E and four sites in Puget Sound. For comparison, we also analyzed gutted bodies of juvenile Chinook salmon from eight hatcheries in the LCR&E as well as samples of the hatchery fish feeds. The mean ∑PBDE concentrations measured in bodies of juvenile Chinook salmon from the different sites ranged from 350 to 2800xa0ng/g lipid weight, whereas those in stomach contents ranged from less than the quantitation limit (<2xa0ng/g wet weight) to 39xa0ng/g wet weight. The levels of PBDEs in the hatchery fish were significantly lower than those measured in the salmon samples collected from the LCR&E and Puget Sound. These results show that outmigrant juvenile Chinook salmon in the LCR&E and Puget Sound have been exposed to PBDEs in the environment and that these chemicals are bioaccumulating in their tissues; thus, the potential effects of PBDEs on these salmon should be further investigated.

Indicators of reproductive development in prespawning female winter flounder (Pleuronectes americanus) from urban and non-urban estuaries in the northeast United States

The relationship between exposure to xenobiotic compounds and ovarian development was evaluated in prespawning female winter flounder (Pleuronectes americanus) sampled from eleven sites on the northeast coast of the United States during the 1988 and 1989 spawning seasons. Three sites were located in Boston Harbor, MA, four sites were in Raritan Bay, NJ and four sites were in nearby embayments. Sediments from these sites exhibited a wide range in concentrations of xenobiotic compounds (e.g. aromatic hydrocarbon (PAH) concentrations ranged from 20 to 50 000 ng/g dry wt. and polychlorinated biphenyl (PCB) concentrations ranged from 2 to 1400 ng/g dry wt.), with the sites in Boston Harbor and Raritan Bay the most heavily contaminated. The following parameters associated with ovarian development were measured: ovarian developmental stage, ovarian atresia, gonadosomatic index, plasma estradiol, fecundity and egg weight. Contaminant exposure was assessed by measuring concentrations of fluorescent aromatic compounds (FACs) in the bile, hepatic aryl hydrocarbon hydroxylase (AHH) activity, concentrations of PCB in liver, ovary and brain and concentrations of xenobiotic-DNA adducts in liver tissue. Additionally, liver tissue was examined histologically for the presence of suspected toxicopathic lesions. In general, indicators of contaminant exposure were elevated and prevalences of suspected toxicopathic lesions were highest in fish from sites within Boston Harbor and Raritan Bay. Hepatic AHH activity, however, was heavily influenced by the reproductive cycle and showed little correlation with other indicators of contaminant exposure. Evidence of decreased egg weight and increased atresia in fish with high tissue concentrations of PCB or high levels of FACs in bile was observed. However, contaminant exposure had no clear negative impact on gonadal recrudescence, gonadosomatic index, plasma estradiol concentrations, or fecundity in female winter flounder. These results are in contrast to results with another Pleuronectid species, English sole (Pleuronectes vetulus), which shows inhibited gonadal development and lower plasma estradiol concentrations at contaminated sites in Puget Sound, WA. The apparent difference between English sole and winter flounder in susceptibility to contaminant-induced reproductive dysfunction could be related to a number of factors, including the differences in the migratory behavior of the two species during the reproductive season. English sole reside in contaminated estuaries throughout vitellogenesis and move offshore to spawn, while winter flounder often remain offshore for extended periods during early vitellogenesis and move into contaminated estuaries prior to spawning. Because of these contrasting migration patterns, both the duration and timing of exposure to contaminants during gonadal recrudescence may differ substantially in these two species and may contribute, in part, to the observed differences in the prevalence of reproductive dysfunction in fish from contaminated estuaries.

Approaches for Determining Effects of Pollution on Fish Populations of Puget Sound

Abstract Puget Sound is a large marine and estuarine ecosystem in Washington State that serves as the habitat for a number of recreationally and commercially important species of groundfish and Pacific salmon Onchorhynchus spp. Over the past several decades, the human population of the Puget Sound drainage basin has increased substantially, resulting in increased habitat degradation and chemical pollution. There is now a body of evidence showing that groundfish and salmon in Puget Sound are experiencing a range of biological effects from chemical contaminant exposure, including impairment of several stages in the reproductive process, increased susceptibility to pathogens resulting from altered immune competence, and development of toxicopathic diseases. Preliminary studies suggest the potential for reduced survival of fish from urban areas of Puget Sound resulting from increased infectious and idiopathic diseases. The question that now must be addressed is whether contaminant-related reductions in reprod...

Disease Susceptibility of Hatchery Snake River Spring–Summer Chinook Salmon with Different Juvenile Migration Histories in the Columbia River

Various methods have been developed to mitigate the effects of dams on juvenile Pacific salmon Oncorhynchus spp. migrating to the Pacific Ocean through the Columbia River basin. In this study, we examined the health of hatchery Snake River spring and summer Chinook salmon relative to two mitigating strategies: dam bypass and transportation (e.g., barging). The health of out-migrants was assessed in terms of the difference in the incidence of mortality among fish, categorically grouped into no-bypass, bypass, and transportation life histories, in response to challenge with the marine pathogen Listonella anguillarum during seawater holding. These three life histories were defined as follows: (1) fish that were not detected at any of the juvenile bypass systems above Bonneville Dam were classified as having a no-bypass life history; (2) fish that were detected at one or more juvenile bypass systems above Bonneville Dam were classified as having a bypass life history; and (3) fish that were barged were classified as having the transportation life history. Barged fish were found to be less susceptible to L. anguillarum than in-river fish-whether bypassed or not-which suggests that transportation may help mitigate the adverse health effects of the hydropower system of the Columbia River basin on Snake River spring-summer Chinook salmon. The findings of this study are not necessarily transferable to other out-migrant stocks in the Columbia River basin, given that only one evolutionarily significant unit, that is, Snake River spring-summer Chinook salmon, was used in this study.

The use of plasma parameters to predict ovarian maturation stage in English sole Parophrys vetulus Girard

Abstract Oocyte development and associated changes in condition factor and levels of estradiol, vitellogenin [measured as alkali-labile protein-associated phosphate (ALP)], calcium, magnesium, phosphate, total protein, triglycerides, and glucose in plasma were monitored in female English sole Parophrys vetulus Girard from Puget Sound throughout the 1985–86 and 1986–87 spawning seasons. Discriminant analysis was applied to data collected in 1985–86 to select a suite of parameters that could accurately differentiate between female sole in different stages of ovarian maturation. On the basis of plasma levels of ALP, estradiol, total protein, and triglycerides, fish in five histologically determined ovarian maturation stages (i.e., regressed, previtellogenic, vitellogenic, spawning, and spawned out) could be distinguished from each other with ≈70% accuracy. When the model was used to classify female sole collected in 1986–87, ovarian maturation stage was predicted correctly in 68% of the fish examined, a significantly greater proportion than the 20% which would be expected on the basis of chance alone. This method for predicting ovarian developmental stage would be particularly useful in laboratory studies in which it is necessary to assess the stage of gonadal development without sacrificing test animals, and could also be applicable in field studies designed to monitor reproductive cycles of marine species.