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The article discusses a study related to assessment of non-native fish dispersal from a freshwater aquaculture site. It mentions completion of freshwater aquaculture of cyprinid fishes in pond systems; and limited natural dispersal at the aquaculture facility in Southern England that was licensed for Pseudorasbora parva fishes. It also highlights issues when P. parva were detected drifting out of the site.

The topmouth gudgeon, Pseudorasbora parva, has been described as Europe’s most invasive fish. To control their UK invasion, some lentic populations at risk of causing fluvial dispersal have been eradicated. The first of these operations was from a lake in north-west UK in March 2005 using rotenone application; prior to eradication, their mean density was estimated as 6.1 m−2 whereas since eradication, no P. parva have been recorded. Prior to rotenone application, the majority of native fishes were removed, held off-site and reintroduced following degradation of rotenone to safe levels. In the three growth seasons since their reintroduction and P. parva eradication, the abundance, somatic growth rate and production of roach Rutilus rutilus and common bream Abramis brama have increased significantly; production is now driven by a lower number of comparatively larger, faster growing individuals. These data suggest that the eradication of this P. parva population has been highly beneficial for the growth, recruitment and production of these native species. [ABSTRACT FROM AUTHOR]

Two topmouth gudgeon Pseudorasbora parva populations were studied in adjacent ponds in Northwest England to determine the influence of density on the expression of their life history traits. Initial introduction into one of these ponds had been in 2000, with establishment of an abundant population (density in March 2005: 6.1 ± 3.2 m−2). Their transfer into the adjacent pond only occurred during brief periods of seasonal connection; this population was of low abundance (density in March 2005: 0.6 ± 0.5 m−2) and was still colonising the pond at the time of sampling. In the low-density population, individuals were significantly faster growing, maturing earlier (generally in their first year of life) and more fecund at length and age (mean batch fecundity at 50 mm: 883 compared with 473 eggs). These traits were advantageous in maximising early life reproduction, facilitating their colonisation and population establishment, a process already completed in the high-density population. [ABSTRACT FROM AUTHOR]

The article presents the proliferation of managed, stillwater fisheries with non-native fishes. It gives out a demand for increased angling diversity and large game fishing opportunities. Also, this has enabled the species such as the catfish to achieve a relatively wide distribution, despite the ecological concerns. The existence of legislation in England and Wales regulates the distribution of non-native species in fisheries. Their high angling demand often results in illegal introduction, specifically species of sturgeon of the genus Acipenser.

The topmouth gudgeon ( Pseudorasbora parva) is a species that is becoming invasive in UK waters. Few biological studies have been completed on the species in this extended range, resulting in sparse information in some aspects of their invasion biology. Regarding length–weight relationships, this is remedied in this study by providing data for 10 lake populations in the UK. Using fish length range 2.5–11.8 cm, values of a and b in the length–weight equation are provided. Values of b ranged between 2.76 and 3.32. Across all lakes, the relationship was W = 0.011L3.03, with weight in grams and length (fork) in cm. [ABSTRACT FROM AUTHOR]

Five specimens of bighead carp Hypophthalmichthys nobilis were captured from a lake in eastern England in January 2006, their first confirmed recording in the wild in the U.K. They varied in fork lengths from 746 to 796 mm and mass from 10·0 to 13·5 kg. All the fish were age 9 years and were slow growing compared to populations elsewhere in their expanded range. [ABSTRACT FROM AUTHOR]

The North American catfish Ameiurus catus is recorded for the first time in Great Britain. An albino variety of 620 mm fork length and 4550 g was believed to have been an ornamental fish that was introduced subsequently into the wild. [ABSTRACT FROM AUTHOR]

1. Temperate regions with fish communities dominated by cold-water species (physiological optima <20 °C) are vulnerable to the effects of warming temperatures caused by climate change, including displacement by non-native cool-water (physiological optima 20–28 °C) and warm-water fishes (physiological optima >28 °C) that are able to establish and invade as the thermal constraints on the expression of their life history traits diminish. 2. England and Wales is a temperate region into which at least 38 freshwater fishes have been introduced, although 14 of these are no longer present. Of the remaining 24 species, some have persisted but failed to establish, some have established populations without becoming invasive and some have become invasive. The aim of the study was to predict the responses of these 24 non-native fishes to the warming temperatures of England and Wales predicted under climate change in 2050. 3. The predictive use of climate-matching models and an air and water temperature regression model suggested that there are six non-native fishes currently persistent but not established in England and Wales whose establishment and subsequent invasion would benefit substantially from the predicted warming temperatures. These included the common carp Cyprinus carpio and European catfish Silurus glanis, fishes that also exert a relatively high propagule pressure through stocking to support angling and whose spatial distribution is currently increasing significantly, including in open systems. 4. The potential ecological impacts of the combined effects of warming temperatures, current spatial distribution and propagule pressure on the establishment and invasion of C.  carpio and S.  glanis were assessed. The ecological consequences of C.  carpio invasion were assessed as potentially severe in England and Wales, with impacts likely to relate to habitat destruction, macrophyte loss and increased water turbidity. However, evidence of ecological impacts of S.  glanis elsewhere in their introduced range was less clear and so their potential impacts in England and Wales remain uncertain. [ABSTRACT FROM AUTHOR]

The article presents a study which discusses the reproductive ecology and diet of the persistent population of black bullhead Ameiurus melas in Great Britain. The study is investigated by analysis of covariance (ANCOVA), stable isotope analysis (SIA), and Bayesian mixing model. Results show that high water temperature has contributed to the spawning of A. melas between June and July.