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The effects of different forms of vitamin C and soybean lecithin on growth performance, feed utilization and body composition of brown bullhead (Ameiurus nebulosus, Lesuer 1819) were evaluated during a 9-week growth trial. A special interest was to investigate a possible combine effect of these nutritional components. The diets used contained three forms of vitamin C (crystallized ascorbic acid, encapsulated L-ascorbic acid and Ca-L-threonate) (100 mg/kg) with and without the combination of soybean lecithin. Besides control diet (K), one more diet was supplemented with soybean lecithin (L) only. One-hundred-ninety-two brown bullhead of about 45 g initial body weight was randomly divided in 24 tanks (115 L each). Testing conditions included 8 fish per tank, with triplicate tanks for treatment. All diets with supplemented components had higher final weight. Specific growth rate, feed conversion rate and condition factor were significantly higher with encapsulated vitamin C diets (CC, CC L ), followed by the results of enriched ascorbic acid diets. Vitamin C and lecithin supplementation showed positive influence on significantly higher number of erythrocytes, haematocrit, triglycerides and total protein. Vitamin C content of muscle and liver tissue was not uniform and was significantly higher in AA L , CC L , CC and AA feeding groups. The fatty acids profile of muscle and liver tissue showed that phospholipids from soybean lecithin and vitamin C diets enhanced the quality of usable part of the fish body. Combine supplementation of vitamin C and soy lecithin indicated positive production effects, but did not cause a statistically significant difference.

The brown bullhead is a fish native to North America that became an invasive species after being introduced into the waters of Europe and other regions. Studies on its sexual cycle and fecundity were conducted on a population from an oxbow lake of the central Vistula River in Poland. The fish ranged in age from 1 + to 9+. The average body length (SL) was 14.4 ± 3.4 cm. Individuals as young as 1 + were already mature. Females lay eggs multiple times from mid-April to mid-June, with absolute fecundity averaging 3227 oocytes and relative fecundity at 46 oocytes g −1 . The highest mean GSI of 1.9 during spawning was recorded in June. The reproductive tract of males takes the shape of lobes and consists of a paired cranial region formed by testes and a caudal region of undefined function. In males, semi-cystic spermatogenesis occurs, with secondary spermatocytes leaving cysts. Males overwinter with tubules filled with spermatids and initiate spermatozoa formation. The highest average GSI of 0.49 was recorded in early April. The brown bullhead observed in the new habitat was characterized by multiple egg laying, earlier maturation of individuals, and spawning in the earlier part of the calendar year, i.e. mid-April to mid-June, compared to its native habitat.

When dealing with invasive fishes, permanent barriers may be best in preventing spread; however, they may not be feasible due to various costs and/or logistical constraints. Alternatively, various non-permanent barriers using electricity, light, sound, pressure, bubbles, and CO 2 are being developed and deployed in efforts to limit the spread of aquatic invasive species or to achieve fish guidance and conservation. However, the effectiveness of these barriers is quite variable, and testing is often lacking for both target and non-target species. We conducted a series of laboratory trials to examine the effects of strobe light on behaviour of Common Carp, Brown Bullhead, and Largemouth Bass. In response to strobe lights, Common Carp and Brown Bullhead stayed significantly farther away compared to the control period and resumed their normal activity once the strobe light was turned off. This suggests that strobe lights may prove to be a useful fish deterrent in the field. Our results also highlight the importance of examining the response of both target and non-target species when evaluating fish deterrent technologies.

Fishes of the Genus Ameiurus (Ictaluridae, Siluriformes) in the Transcarpathian Water Bodies. Movchan, Yu. V., Talabishka, E. M., Velikopolskiy, I. J. - Morphometric standards of two species of the genus Ameiurus Rafinesque, 1820 are analyzed. The diff erences in external morphology between A. melas and A. nebulosus and the boundaries of current distribution of these fishes in the waters of Transcarpathia are determined.

The Brown Bullhead (Ameiurus nebulosus) was first documented in Kansas at a United States Fish and Wildlife Service fish hatchery near Farlington, Kansas in 1955. Some early stockings occurred, but the full extent is unknown. Historical distribution information on the species was limited to three collection records deposited as museum vouchers and two records noted in early manuscripts. We performed a review of the species in Kansas, including information from the Kansas Department of Wildlife, Parks, and Tourism's Fish Sampling Database, museum vouchers, and literature records to determine its known extent in Kansas. The Brown Bullhead has been documented from eleven water bodies throughout six counties. Eight of these records were from impoundments or government-managed wetlands and two records were from streams. Most observations in Kansas occurred in the 1990's, or earlier. The restricted timeframe of most of the collections leaves these populations in doubt, especially considering impoundment renovations that have occurred throughout the last several decades. However, we document a 2019 collection from Ottawa State Fishing Lake, Ottawa County, Kansas. We collected nine Brown Bullhead in this impoundment from June and July 2019. The species has not been documented at any other water body in Kansas since 2004.

Polycyclic aromatic hydrocarbons (PAHs) in both sediment and brown bullhead catfish tissues from the Black River in Lorain County, Ohio, declined by 65% and 93%, respectively, between 1980 and 1982. Sediment PAHs declined an additional 99% by 1987, coincident with the closure of a coking facility in 1983. Contemporaneously, liver cancer in 3- to 4-year-old brown bullheads declined to about one-quarter the 1982 frequency (10% versus 39%) by 1987, while the percentage of livers without any proliferative lesions doubled (42% versus 20%). These changes were significant within age group. Our data affirm a cause-and-effect relationship between PAH exposure and liver cancer in wild fish. The data also support the efficacy of natural, unassisted remediation once the source of the pollution is eliminated.

The Comet assay was used to compare levels of DNA damage in brown bullheads (Ameiurus nebulosus) collected from three known contaminated locations, the Cuyahoga River (OH, USA), Ashtabula River (OH, USA; both tributaries to Lake Erie, USA), and Ashumet Pond (Cape Cod, MA, USA), with brown bullheads collected from three paired reference sites, Old Woman Creek (OH, USA), Conneaut River (OH, USA; both tributaries to Lake Erie), and Great Herring Pond (mainland MA, USA), respectively. Blood was sampled from each fish, and the Comet assay was conducted on erythrocytes. The assay results demonstrate that fish from the three contaminated sites each suffered higher DNA damage compared with fish from their respective reference sites. The results also show that the genetic damage was associated with the occurrence of external lesions and deformities in fish. The Comet assay is sufficiently sensitive to detect exposure of natural fish populations to environmental levels of genotoxic contaminants.

Ultrasonic telemetry was used to determine the swimming depths of brown bullhead (Ameiurus nebulosus) in Motuoapa Bay at the southern end of Lake Taupo, New Zealand. Sonic transmitters equipped with a pressure sensor were surgically implanted in 12 adult fish (295-345 mm FL). Three automatic receivers recorded a total of 61335 data points on swimming depth between 26 November 1998 and 7 November 1999. Brown bullheads swam in water from 0 to 17 m deep but showed some seasonal variations. They were more active at night when they used shallow water extensively, especially during the winter months. They were most mobile in spring when they left Motuoapa Bay, suggesting migratory behaviour. During winter the fish remained more stationary, only moving around inside the bay. The results of this study provide guidance for establishing a brown bullhead control program should it become necessary.[PUBLICATION ABSTRACT]

Fungi suggested to be used in the control of mosquito larvae produce biologically active cyclopeptides - cyclosporins, which can potentially accumulate in the fish feeding the infected larvae. Whereas toxicity of cyclosporins was observed at the higher doses in man and various experimental animals, the fish tolerated surprisingly high cyclosporin blood levels. Hydroxy-cyclosporins predominated among metabolites excreted into water. In contrast, various N-demethylated cyclosporins created the major part of metabolites identified in the liver and bile. Two new metabolites are described - AM1N and AM6N,10N, which were not so far reported from mammals. Due to the much higher tolerance to cyclosporin, brown bullhead can serve the experimental model to obtain cyclosporin metabolites.[PUBLICATION ABSTRACT]

We analysed a 24 cm long sediment sequence (past ~200 years) from an alpine lake (Tatra Mts., Slovakia) for chironomids, cladocerans, and diatoms to reconstruct the effects of a historically documented fish introduction. Our results indicate that fish introduction predated the age of the sequence, and thus, we did not cover the lake’s fishless period. The individual proxies coincide in showing two main lake development stages. The first stage lasted until ~1950 CE and was interpreted as the stage when brown trout and alpine bullhead co-occurred. The extremely low concentration of cladocerans, the dominance of small-bodied chydorids, and the low share of daphnids, together with the low proportion/absence of large-bodied tanypod chironomids, suggest a strong effect of both species. The beginning of the next stage is probably related to the ban on fish manipulations and grazing in the catchment. A significant increase in the total abundance of cladocerans and of daphnids may indicate the extirpation of trout. The steep increase in thermally plastic chironomid taxa since the end of the 20th century indicates climate warming. Generally, while cladocerans primarily indicate fish manipulations, chironomids and diatoms mainly reflect other local and global environmental stressors.