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Welham Green, United Kingdom

Sayer C.D.,University College London | Copp G.H.,Bournemouth University | Copp G.H.,Trent University | Emson D.,University College London | And 4 more authors.
Journal of Fish Biology | Year: 2011

The extent and causes of crucian carp Carassius carassius decline were assessed during an initial study of c. 25 ponds in north Norfolk, eastern England, U.K., which was then replicated (a validation study) on another c. 25 ponds in an adjacent area. Of these ponds, c. 40 are known to have contained C. carassius during the 1970s-1980s. In the initial and validation studies, C. carassius were found in only 11 of these ponds, yielding declines of 76% (five of 21 ponds) and 68% (six of 19 ponds), respectively (72% decline overall). Non-native cyprinids, including goldfish Carassius auratus and common carp Cyprinus carpio and their hybrids with C. carassius, were observed in 20% of the ponds. Causes of C. carassius local extinction from 21 ponds were confidently determined as desiccation due to drought, terrestrialization and habitat deterioration, hybridization and competition with non-native cyprinids, agricultural land reclamation and predation (after the introduction of pike Esox lucius). This study led to C. carassius being designated as a Biodiversity Action Plan (BAP) species in the county of Norfolk, the first formal conservation designation for the species in the U.K. The C. carassius BAP plan aims to halt the decline of this much overlooked species through reintroductions and selective stocking of suitable ponds within the native range of the species. © 2011. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

Copp G.H.,Center for Environment | Copp G.H.,Bournemouth University | Tarkan A.S.,Center for Environment | Tarkan A.S.,Mugla University | And 3 more authors.
Aquatic Invasions | Year: 2010

Introductions of an Asian cyprinid, goldfish Carassius auratus, are known to pose a genetic threat to crucian carp Carassius carassius, which is native to northern parts of central and western Europe, including southeast England. However, there are no known studies in Europe of goldfish impacts on crucian carp growth and life-history traits, nor on the recipient ecosystems. The present study is the first such attempt, and compares the plants, invertebrates and fish biology (growth, condition, reproduction) in six ponds, two containing crucian carp only (allopatry), two containing goldfish only (allopatry), and two with both species (sympatry). Feral goldfish growth was greatest in sympatry with native crucian carp, whereas crucian carp growth was similar regardless of goldfish presence or absence. However, body condition (LK) and relative fecundity (per unit of body weight) of crucian carp was greatest in sympatry with feral goldfish. LK increased significantly with increasing water conductivity in goldfish but not in crucian carp, and LK was not related to pond invertebrate densities in either fish species. Differences in the plant and aquatic invertebrate communities observed in the study ponds could not be attributed to the introduction and establishment of goldfish, however non-native plant and invertebrate species were observed only in ponds containing goldfish. Differences in growth and condition between the two Carassius species does not appear to be due to differences in available food, so elevated somatic growth and reproductive output in crucian carp and faster growth in goldfish in sympatry may be due to non-dietary competitive interactions. The present preliminary study highlights the difficulties of assessing 'real world' impacts of non-native species on native species and ecosystems as well as the need for further study of feral goldfish impacts on European pond ecosystems in general and on native congener crucian carp in particular. © 2010 The Author(s).

Rees E.M.A.,UK Environment Agency | Britton J.R.,Bournemouth University | Godard M.J.,CEFAS Lowestoft | Crooks N.,Hampshire College | And 4 more authors.
Journal of Applied Ichthyology | Year: 2014

The efficacy and sub-lethal consequences of single and double tagging European catfish Silurus glanis with Petersen disc and passive integrated transponder (PIT) tags were examined in short (laboratory) and longer-term (field) experiments. Tag retention in the laboratory was 100%, with normal behaviour (i.e. feeding) in all fish returning within 36 h. In the field, 65 of 120 tagged S. glanis were recaptured from five small study ponds, with 85% retaining their PIT tags, though recapture rates and tagging efficacy were highly variable amongst locations. This is consistent with literature for other fishes, suggesting that tagging efficiency is variable across species and largely context dependent (fish length, tagging location, habitat). © 2013 Crown copyright.

Zieba G.,Center for Environment | Zieba G.,University of Lodz | Copp G.H.,Center for Environment | Copp G.H.,Bournemouth University | And 4 more authors.
Aquatic Invasions | Year: 2010

The introduced range of the European cyprinid, sunbleak Leucaspius delineatus, in England was previously limited to parts of southwest England but has now expanded across Southern England. Natural dispersal mechanisms cannot explain their increased distribution and fish stocking was not a factor. Thus, the accidental movement of either their eggs or larvae via anglers' nets was believed to be the mechanism by which these fish were accidentally moved between waters over 100 km apart. This dispersal pathway is difficult to regulate, as is the release of unwanted non-native aquarium and pond fish into open waters by the public. This latter pathway has resulted in the recent releases of species including walking catfish Clarias batrachus, Asian weatherfish Misgurnus mizolepis and white catfish Ameiurus catus. © 2010 The Author(s).

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