There are few reports of dietary Cu (copper) toxicity to Korean bullhead, Pseudobagrus fulvidraco, and little is known about recovery from dietary Cu exposure. In this study, P. fulvidraco (mean ...length 16.9 ± 1.38 cm, and mean weight 53.2 ± 1.22 g) were exposed for 4 weeks to dietary Cu concentration of 0 (control), 700, 900, and 1100 mg Cu kg−1 dry feed to establish maximum tolerable levels of dietary Cu. All fish were then fed the dietary EGCG (Epigallocatechin gallate) concentration of 100 and 500 mg EGCG kg−1 dry feed for a further 2 weeks to assess recovery. We were measured bioaccumulation (in the intestine, liver, and gill tissue), antioxidant enzymes (SOD and CAT) and immune responses (lysozyme and phagocytosis). The Cu exposure induced a significant accumulation in the intestine, liver, and gill tissues and the highest accumulation was observed in intestinal tissues (17–34 fold), but dietary EGCG exposure decreased (about 0.8-fold) Cu concentration in each tissue (ANOVA, P < 0.05). In antioxidant enzymes, SOD and CAT significantly increased by approximately 1.6-fold by dietary Cu exposure in the liver and gill tissue, respectively, but dietary EGCG exposure decreased SOD and CAT by about 1.1-fold, respectively (ANOVA, P < 0.05). For immune responses, lysozyme and phagocytosis in the blood significantly were decreased by approximately 1.5-fold, respectively, by dietary Cu exposure, but dietary EGCG exposure increased lysozyme and phagocytosis by about 1.1-fold, respectively (ANOVA, P < 0.05). During recovery period, bioaccumulation, antioxidant enzymes (SOD and CAT activity), and immune response (lysozyme and phagocytosis activity) tended to alleviate the significant changes by Cu exposure, and the tendency to return normal state was observed in high level of EGCG. The result of this study indicate that Cu exposure to P. fulvidraco affects bioaccumulation, antioxidant enzymes, and immune responses, and high level of EGCG were effective to alleviate the toxic effects of Cu exposure.
•A significant Cu accumulation in specific tissues were observed by dietary Cu exposure.•The antioxidant and immune responses were significantly changed by the Cu exposure.•Dietary EGCG supplementation was significantly effective to alleviate the effects by Cu toxicity.
In a previous study, adaptive responses to a single polycyclic aromatic hydrocarbon (PAH), benzoapyrene (BaP), were identified in brown bullhead (Ameiurus nebulosus) captured from contaminated sites ...across the Great Lakes. The tumor suppressor p53 and phase I toxin metabolizing CYP1A genes showed a elevated and refractory response, respectively, up to the F1 generation (Williams and Hubberstey, 2014). As an extension to the first study, bullhead were exposed to sediment collected from sites along the Detroit River to see if these adaptive responses are attainable when fish from a contaminated site are exposed to a mixture of contaminants, instead of a single compound. p53 and CYP1A proteins were measured again with the addition of phase II glutathione-s-transferase (GST) activity in the present study. Three treatment groups were measured: acute (treated immediately), cleared (depurated for three months and subsequent treatment), and farm raised F1 offspring. All three treatment groups were exposed to clean and contaminated sediment for 24 and 96 h. Acute fish from contaminated sites exposed to contaminated sediment revealed an initial elevated p53 response that did not persist in fish after long-term contaminated sediment exposure. Acute fish from contaminated sites exposed to contaminated sediment revealed refractory CYP1A expression, which disappeared in cleared fish and whose F1 response overlapped with clean site F1 offspring. Decreasing GST activity was evident in both clean and contaminated fish over time, and only clean site fish responded to long-term contaminated sediment deliberately with increasing GST activity. Because p53 and CYP1A gene expression and GST activity responses did not overlap between contaminated fish treatment groups, our study suggests that contaminated fish have acclimated to the contaminants present in their environments and no evidence of adaptation could be detected within these biomarkers.
This paper presents an integrated modelling approach to simulate and assess ecological effects of physical habitat changes in rivers. An ecohydraulic simulation tool was created by combining a 1D ...hydraulic model based on HEC-RAS software and the fish habitat module of CASiMiR, a fuzzy logic-based ecohydraulic modelling system. This tool was applied on a river stretch commonly occurring in Belgium and elsewhere in Europe. In particular the effect of weir removal on habitat suitability for bullhead (
Cottus gobio L.) was simulated. Physical conditions of the studied stretch after weir removal were simulated with a hydraulic model. CASiMiR linked these conditions to ecological expert knowledge to calculate habitat suitability for three life stages of bullhead at four different flow rates based on fuzzy logic. Results indicated that after weir removal, habitat suitability increased significantly for all life stages and all flow rates. The presented approach is promising regarding fish community assessment and ecological river engineering.
This addresses current advances and challenges in fisheries and aquaculture science. Exposure of larval fish to elevated temperatures during embryological development may induce craniofacial and ...morphological alterations, which are suggested possible impacts of global warming. Molecular markers shed new light on the ontogenetic migration of stream fishes. Fast growth rates, early age at maturity, moderate fecundity, and diverse diet explain the potential for introduced fishes to dominate fish communities in their native and introduced range. Taking videos of marine benthic habitats supports low-impact, real-time monitoring of species occurrence. Among heavily fished species, almost half had outdated demographic assessments that would benefit from the integration of data from fisheries sources and improved collaboration among fishery stakeholders and managers. The continued growth of aquaculture will depend upon developing feeds that improve the growth, oxidative status, and immune response of fed cultured organisms. New aquaculture feedstuffs might be derived from plants or microbes, and new additives would include ghrelins and dietary symbiotics. The effects of these constituents on survival, growth, gut histomorphology, immune response were assessed for cultured freshwater and marine species. The results provide suggestions for advances in aquafeeds for the species studied and for cultured fishes more generally. The scientific advances realized with the use of new tools provide the basis for addressing global challenges to fisheries, aquaculture and for ongoing scientific research.
The prevalence of liver and skin tumors in brown bullhead (Ameiurus nebulosus) from the Anacostia River (Washington, DC) and nearby areas was determined in 2014, 2015, and 2016. The objectives were ...to (1) compare tumor prevalence across space and time; (2) analyze the 1992–2016 Chesapeake Bay Tumor Database to identify reference locations and test age, length, weight, and sex as covariates; and (3) explore whether changes in bullhead exposure to contaminants can explain the observed trends. With logistic regression, we reported large statistically significant decreases in liver tumor probabilities in bullheads from the Anacostia CSX Bridge (ANAC) area between 1996 and 2001 (merged: female, 77.8%; male, 48.6%), 2009 to 2011 (female, 42.5%; male, 16.6%), and 2014 to 2016 (female, 18.0%; male, 5.7%). Skin tumors decreased by a factor of six in both females and males. Polycyclic aromatic compounds (PAC) initiate liver neoplasms and polychlorinated biphenyls (PCBs) and DDT compounds are promoters. The causes of skin tumors in bullhead are uncertain. Biomarker and tissue data show decreases in PAC-DNA adducts and PCB and DDT contamination in ANAC bullheads. It is likely that the decreased liver tumor prevalence is associated with decreased exposure to these contaminants.
In the Călimani National Park, the inventory of the fish species of community importance, carried out in 2013 through a project from the Sectoral Operational Program for Environment, revealed that ...there is only one species of community interest in the park, namely Cottus gobio (bullhead). This is a normal fact given that the site is located at altitudes ranging from a maximum of 2083 m to a minimum of 470, and most of the waters are represented by alpine creek. In the all four fishing campaigns, 30 tributaries were investigated and a total of 220 individuals were fished out of which: 156 individuals of river trout (Salmo trutta fario), 9 individuals of common bullhead (Cottus gobio), 52 individuals of rare bullhead (Cottus poecilopus), 2 individuals of grayling (Thymallus thymallus) and 1 individuals of minnow (Phoxinus phoxinus). Ihtiofauna has a very low diversity, being constantly represented by one species of fish, Salmo trutta fario, which is well suited to the conditions of the creek situated on slopes of 1-3 m/km. Thus, out of the 30 investigated water courses, Salmo trutta fario is present in 17 water courses. Instead of this, Cottus gobio, a species of fish of community importance, has a very low presence on the territory of Calimani National Park, this situation is, to some extent, inadequate.
Black bullheads Ameiurus melas are an environmentally tolerant omnivorous fish species that are found throughout much of North America and parts of Europe. Despite their prevalence, black bullheads ...are an infrequently studied species making their biology, ecology, and life history poorly understood. Although limited information has been published on black bullheads, evidence suggests that bullheads can dominate the fish biomass and have profound influences on the fish community in some north temperate USA lakes. The goal of our study was to provide additional information on black bullhead population demographics, growth rates, life history characteristics, and seasonal diet preferences in a northern Wisconsin lake. Using common fish collection gears (fyke netting, electrofishing), fish aging protocols, fecundity assessments, and diet indices, our results suggested that black bullheads exhibited relatively fast growth rates, early ages at maturity, moderate fecundity, and a diverse omnivorous diet. Due to these demographic and life history characteristics, black bullheads have the potential to dominate fish community biomass in their native and introduced range. Results from our study may inform the management of black bullhead as native and invasive species.
Fisheries managers used the fish toxicant rotenone to eradicate an undesirable brown bullhead (Ameiurus nebulosus) population and all other fish species at Hyatt Reservoir, Oregon, on 12 October ...1989. This 4-yr study (1988–1990, 1992) compared effects of that rotenone project on Ospreys (Pandion haliaetus) nesting at Hyatt Reservoir and nearby Howard Prairie Reservoir (untreated reference)—the latter a reservoir where both brown bullheads and hatchery-released rainbow trout (Oncorhynchus mykiss) prospered. Because Hyatt Reservoir was treated after Osprey fall migration in 1989, the first 2 yr (1988 and 1989) yielded pretreatment information: number of Osprey pairs was unchanged and reproductive rates were similar and consistent at the two reservoirs. Yearling fish (200–250 mm) were restocked at Hyatt Reservoir in the spring of 1990 and Ospreys returned each year following rotenone treatment, with no decline in the number of occupied or active nests. The negative effect of the rotenone treatment on Ospreys was short-term, resulting in reduced reproductive rates (young/occupied nest, young/active nest, and young/successful nest) during the first nesting season posttreatment, although hatching rates were not affected. Osprey dive success and prey delivery rates declined sharply in 1990, leading to competition for food among siblings and brood reduction. Osprey reproductive rates and prey delivery rates at Hyatt Reservoir in both 1990 and 1992 remained below the extremely high pretreatment rates, but within the range required for population stability. Serious adverse effects of the fish loss on Osprey reproduction were minimized by: (1) the delay of the rotenone application until after breeding season, (2) the restocking of the treated reservoir in the following spring with some larger (yearling) fish (though the timing was late), (3) the maintenance of a supplemental feeding program for a nesting pair of Bald Eagles (Haliaeetus leucocephalus), which minimized kleptoparasitism on Ospreys, and perhaps most important (4) the presence of nearby water bodies, where Osprey obtained some fish in the 1990 and 1992 breeding seasons.
The distribution patterns of alpine bullhead Cottus poecilopus in three tributary streams of the Rožnovská Bečva River (Danube basin) were studied with respect to temperature, oxygen concentration ...and saturation, shading, current, conductivity, total organic carbon (TOC), nitrates and phosphates, biochemical oxygen demand (BOD5), pH, redox potential, bottom grain structure, density of macroinvertebrates and the abundance of brown trout Salmo trutta. Sites with lower abundance per hectare of C. poecilopus differed significantly in dissolved oxygen saturation, density of macroinvertebrates during the autumn period (positive correlation with C. poecilopus) and in abundance per hectare of S. trutta (negative correlation). These results indicate that these factors significantly influence the distribution of this endangered species in the studied catchment and that stocking of S. trutta will impair its recovery.
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