Salmon and Freshwater Team

Suffolk, United Kingdom

Salmon and Freshwater Team

Suffolk, United Kingdom
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Almeida D.,Salmon and Freshwater Team | Almeida D.,Bournemouth University | Merino-Aguirre R.,Complutense University of Madrid | Vilizzi L.,Ichth Oz Environmental Science Research | And 3 more authors.
PLoS ONE | Year: 2014

Pumpkinseed Lepomis gibbosus (L.) are successful invaders in Europe, where this species exerts multiple ecological effects, mainly through trophic interactions. Behavioural interference represents a potential impact for native fauna and this is of particular conservation concern in the Iberian Peninsula because of the highly valuable endemic fauna inhabiting streams of this region. However, aggressive interactions have not previously been examined under natural conditions in Iberian fresh waters. To address this gap in knowledge, the aim of the present study was to assess the effect of pumpkinseed aggression on endemic fauna of an Iberian stream, the River Bullaque (central Spain). In September 2009, we analysed the aggression and environmental contexts of these behavioural interactions by snorkelling: aggressor size, aggression type, shoal size, previous activity to aggression, recipient species, response to aggression, microhabitat structure and prey availability. Small pumpkinseed displayed more threat and fewer pursuit behaviours relative to medium and large individuals, reflecting an ontogenetic behavioural shift from low to high aggression intensity. Small aggressors came from large shoals, with bottom feeding being the most frequently observed activity prior to an aggressive interaction; whereas large pumpkinseed were less gregarious and they were mostly ambulating within the water column prior to aggression. Recipient species of aggression included non-native crayfish and fishes, and more importantly, endemic fishes and frogs. Retreat was the most common response to aggression, irrespective of aggressor size. Small pumpkinseed displayed aggressive behaviours over coarse substrata containing elevated macrobenthos biomass; whereas aggression by large individuals was observed in deeper waters. These findings suggest that small and large pumpkinseed exert a high impact on other stream residents through aggression in competition for food and territory defence, respectively. This study highlights the usefulness of direct observations in the wild for assessing the effects of behavioural interference of invasive fishes on Iberian aquatic communities. © 2014 Almeida et al.

Lawson L.L.,University of Florida | Hill J.E.,University of Florida | Vilizzi L.,Murray Darling Freshwater Research Center | Hardin S.,Florida Fish And Wildlife Conservation Commission | And 3 more authors.
Risk Analysis | Year: 2013

The initial version (v1) of the Fish Invasiveness Scoring Kit (FISK) was adapted from the Weed Risk Assessment of Pheloung, Williams, and Halloy to assess the potential invasiveness of nonnative freshwater fishes in the United Kingdom. Published applications of FISK v1 have been primarily in temperate-zone countries (Belgium, Belarus, and Japan), so the specificity of this screening tool to that climatic zone was not noted until attempts were made to apply it in peninsular Florida. To remedy this shortcoming, the questions and guidance notes of FISK v1 were reviewed and revised to improve clarity and extend its applicability to broader climatic regions, resulting in changes to 36 of the 49 questions. In addition, upgrades were made to the software architecture of FISK to improve overall computational speed as well as graphical user interface flexibility and friendliness. We demonstrate the process of screening a fish species using FISK v2 in a realistic management scenario by assessing the Barcoo grunter Scortum barcoo (Terapontidae), a species whose management concerns are related to its potential use for aquaponics in Florida. The FISK v2 screening of Barcoo grunter placed the species into the lower range of medium risk (score = 5), suggesting it is a permissible species for use in Florida under current nonnative species regulations. Screening of the Barcoo grunter illustrates the usefulness of FISK v2 as a proactive tool serving to inform risk management decisions, but the low level of confidence associated with the assessment highlighted a dearth of critical information on this species. © 2012 Society for Risk Analysis.

Nunn A.D.,University of Hull | Copp G.H.,Salmon and Freshwater Team | Copp G.H.,Bournemouth University | Vilizzi L.,La Trobe University | Carter M.G.,UK Environment Agency
Ecology of Freshwater Fish | Year: 2010

The population behaviours associated with the migrations of fishes in lowland river ecosystems are amongst the most poorly-understood dispersal mechanisms of temperate freshwater organisms. This study evaluated the influence of four environmental variables (light levels, river discharge, water temperature and water velocity) on the timing, intensity and direction of fish movements between the River Avon (Hampshire, England) and a small floodplain tributary, Ibsley Brook, over a 12-month period. Using canonical correspondence analysis (CCA) to identify patterns of movement (by groups of species) and the relative strengths of explanatory variables in the data, the probability of fishes migrating between the river and tributary was determined using Bayesian modelling. The intensity and direction of fish movements between the river and tributary varied temporally, both on a diel and seasonal basis, and there were species- and age-specific patterns in behaviour. Diel movements appeared to be triggered by changes in light intensity and brook water velocity, whereas seasonal movements were mostly driven by changes in river discharge and water temperature, particularly those associated with floods. This study emphasises the importance of connectivity in river systems, as fishes migrated in all conditions, but especially during rapidly-rising discharge. © 2009 John Wiley & Sons A/S.

Almeida D.,Salmon and Freshwater Team | Argent R.,UK Environment Agency | Ellis A.,UK Environment Agency | England J.,UK Environment Agency | And 3 more authors.
Limnologica | Year: 2013

Assessment of population biology at early establishment stages is a fundamental component of conservation monitoring programmes, such as for invasive signal crayfish Pacifastacus leniusculus. Population structure, body condition (including its relation to density-dependence), spatial patterns and habitat relationships were examined between September and October 1997 along the lower River Stort catchment (Thames River catchment, UK). A higher proportion of females was observed at intermediate sizes, whereas the largest individuals were males. Body condition was positively associated with total crayfish abundance in females but not males. Principal components analysis of the population data (by gender and size) across sampling sites revealed three distinct groups (large males, large females, small crayfish of mixed gender), with large males having significantly (analysis of covariance) lower body condition. Multiple regression of crayfish population and habitat data revealed: increasing abundance was associated with high total suspended solids (e.g. burrowing behaviour) in all size/gender groups except medium and large males; decreasing abundances of large males and females with increasing hydrodynamic efficiency (i.e. Froude number); and increasing abundance of large males and females with increasing substratum roughness. Signal crayfish population structure in the River Stort suggests an elevated potential for dispersal and reinforcement throughout the River Lee catchment. The observed spatial and habitat segregation of crayfish by gender and size appears to reflect a female reproductive strategy that avoids contact between progeny and big aggressive/cannibalistic males. Furthermore, intra-male competition is the likely reason for the lower body condition of big males, given the lack of a negative relationship between male body condition and crayfish abundance. The comparison with established populations elsewhere shows that a sex-ratio biased towards females could be a good descriptor to detect invading populations. Potential threats posed by signal crayfish for the conservation of River Stort catchment are predation, competition and habitat alteration. © 2012 .

Puntila R.,University of Helsinki | Vilizzi L.,Murray Darling Freshwater Research Center | Lehtiniemi M.,Finnish Environment Institute | Copp G.H.,Salmon and Freshwater Team | And 2 more authors.
Risk Analysis | Year: 2013

The climatic conditions of north temperate countries pose unique influences on the rates of invasion and the potential adverse impacts of non-native species. Methods are needed to evaluate these risks, beginning with the pre-screening of non-native species for potential invasives. Recent improvements to the Fish Invasiveness Scoring Kit (FISK) have provided a means (i.e., FISK v2) of identifying potentially invasive non-native freshwater fishes in virtually all climate zones. In this study, FISK is applied for the first time in a north temperate country, southern Finland, and calibrated to determine the appropriate threshold score for fish species that are likely to pose a high risk of being invasive in this risk assessment area. The threshold between "medium" and "high" risk was determined to be 22.5, which is slightly higher than the original threshold for the United Kingdom (i.e., 19) and that determined for a FISK application in southern Japan (19.8). This underlines the need to calibrate such decision-support tools for the different areas where they are employed. The results are evaluated in the context of current management strategies in Finland regarding non-native fishes. © 2013 Society for Risk Analysis.

Vilizzi L.,Salmon and Freshwater Team | Vilizzi L.,Bournemouth University | Vilizzi L.,Trent University | Copp G.H.,Salmon and Freshwater Team | And 2 more authors.
Risk Analysis | Year: 2013

The Fish Invasiveness Scoring Kit (FISK) is currently one of the most popular pre-screening tools for freshwater fishes. A recent upgrade has ensured its wider climatic relevance to countries with subtropical regions. This enhancement is of particular importance to Australia, which encompasses tropical, arid, and temperate zones, and where the introduction of non-native fish species poses a significant risk to biodiversity. In this study, 55 fish species previously evaluated in a U.K.-based calibration of FISK are reassessed for their potential invasiveness in the Murray-Darling Basin (MDB; southeastern Australia), the continent's largest catchment encompassing arid and temperate climates. Approximately half of the species were classed as "medium risk" and the other half as "high risk," and the ≥19 threshold previously identified from the calibration study was confirmed. The three highest scoring species (common carp Cyprinus carpio carpio, goldfish Carassius auratus, and eastern mosquitofish Gambusia holbrooki) were those already present and invasive in the area, whereas nearly half of the tropical and subtropical species had lower scores compared to U.K. assessments, possibly because of climate change predictions of drier conditions across the MDB. There were some discordances between FISK and two Australian-based assessment protocols, one of which is qualitative and the other represents a simplified version of FISK. Notably, the Australian origins of FISK should provide for an additional reason for further applications of the tool in other RA areas (i.e., drainage basins) of the continent, ultimately encouraging adoption as the country's reference screening tool for management and conservation purposes. © 2012 Society for Risk Analysis.

Vilizzi L.,Murray Darling Freshwater Research Center | Copp G.H.,Salmon and Freshwater Team | Copp G.H.,Trent University | Britton J.R.,Bournemouth University
Knowledge and Management of Aquatic Ecosystems | Year: 2013

Suspected of being in decline, the European barbel Barbus barbus population of the River Lee, a heavily-modified river in South East England, has been the subject of investigations to identify factors associated with perceived population decreases. Population surveys between 1995 and 1999 captured a total of 912 individuals, and standard length (SL) frequency analyses between years suggested that the population decline was not related to juvenile recruitment but rather to a recruitment bottleneck in fish 300-340 mm SL. This bottleneck probably results from insufficient available habitat suitable to this size class. Of the sampled fish, scales were removed from 764 and were used in a scale ageing exercise among three researchers. Analyses of their independent age estimates revealed variable interpretations, which arose from uncertainties relating to the difficulty of analysing scale patterns from relatively large, slow-growing fish. Nevertheless, error was within published acceptable margins, and age estimates revealed B. barbus in the river to age 10 years, lower than in many UK rivers. The SL-at-age growth curve was characterised by very fast growth in the initial years of life. Thus, the causal factors in the decline of this B. barbus population appear to have been in the adult life-stage habitat and were likely related to the loss of longitudinal connectivity, mainly due to the presence of water retention structures. River and aquatic ecosystem remediation strategies should therefore focus on enhancing longitudinal connectivity in conjunction with the ongoing improvement of water quality and ecosystem integrity. © ONEMA, 2013.

Zieba G.,Salmon and Freshwater Team | Fox M.G.,Trent University | Copp G.H.,Salmon and Freshwater Team | Copp G.H.,Bournemouth University
Journal of Fish Biology | Year: 2010

In an experimental comparison of pumpkinseed Lepomis gibbosus reproduction under ambient and climate change water temperature regimes, spawning occurred earlier in the season, which is likely to lead to greater young-of-the-year survival with concomitant implications in the U.K. under warmer climatic conditions. © 2010 Crown Copyright. Journal of Fish Biology © 2010 The Fisheries Society of the British Isles.

Almeida D.,Salmon and Freshwater Team | Tobes I.,University of Navarra | Miranda R.,University of Navarra | Copp G.H.,Salmon and Freshwater Team | And 2 more authors.
Canadian Journal of Zoology | Year: 2012

Reproduction of pumpkinseed sunfish (Lepomis gibbosus (L., 1758)) in the species' native range often involves cuckoldry, consisting of dominant nest-guarding (parental) males and the participation by small "sneaker" males. However, it remains unknown whether this behaviour occurs in populations of non-native pumpkinseed. Thus, the present study describes the phenotypic features of cuckoldry under contrasting environmental conditions (lentic versus lotic) in southern Europe. Parental and sneaker pumpkinseeds were captured in the summer of 2011 from the River Bullaque (central Spain) and from the Encinarejo Reservoir (southern Spain). No differences in total length were observed in sneaker males, although individuals of ages 1+ and 2+ were significantly predominant in the river and the reservoir, respectively. Parental males were larger and older in the reservoir than in the river. Gonadosomatic and hepatosomatic indices were significantly higher in sneaker than in parental males at both sites. Body condition was lower in sneaker males in the river. Both ingested biomass and the proportion of full stomachs were lower in parental males at both sites, being significant in all cases except ingested biomass in the river. Sneaker males achieved a higher gonadosomatic index than parental males. In contrast, parental males had higher body condition indices than sneakers. Results demonstrate the high ecological plasticity of pumpkinseed sunfish to display natural behaviours out of its native area.

Tarkan A.S.,Muǧla University | Gaygusuz O.,Istanbul University | Gursoy Gaygusuz C.,Trakya University | Sac G.,Istanbul University | And 2 more authors.
Fisheries Management and Ecology | Year: 2012

Gibel carp, Carassius gibelio (Bloch), impacts on native fish species have been reported but little studied despite a long history of introductions in Europe. This species is able to reproduce gynogenetically, which involves the use of sperm from males of other species to activate egg development, so reproductive competition is a likely but virtually unstudied impact of gibel carp on native fishes. This study evaluates the impact of introduced C. gibelio on the population biology of native fishes over a 6-year period in a mesotrophic drinking water reservoir in north-western Turkey. A dramatic decrease in the relative density (i.e. catch per unit effort) of native species correlated significantly with an increase in C. gibelio relative density. Growth characteristics (back-calculated ages, growth index and relative condition) and length at maturity did not differ significantly among years in C. gibelio and native fishes. Relative density, duration of spawning, reproductive effort and gonado-somatic index of C. gibelio increased with some water quality variables [total phosphorus (TP); chlorophyll-a (Chl-a)] and coincided with decreasing trends for natives. However, TP and Chl-a were not correlated with growth features in C. gibelio or natives fishes. The results suggest that the decline in the reservoir's native cyprinid populations is likely due to a combination of degrading environmental conditions and a disparity in reproductive effort, with introduced C. gibelio invasion facilitated by gynogenetic reproduction and an observed interference with native fishes during spawning. © 2012 Blackwell Publishing Ltd.

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