Publications by year
Stakenas S, Copp GH, Scott DM
(2009). Tagging effects on three non-native fish species in England (Lepomis gibbosus, Pseudorasbora parva, Sander lucioperca) and of native Salmo trutta. Ecology of Freshwater Fish
Tagging effects on three non-native fish species in England (Lepomis gibbosus, Pseudorasbora parva, Sander lucioperca) and of native Salmo trutta
To address the dearth of information on tagging effects and long-term survivorship of tagged fish in native and introduced species, laboratory and field investigations were undertaken on three non-native fish species (pumpkinseed Lepomis gibbosus; topmouth gudgeon Pseudorasbora parva; pikeperch Sander lucioperca) tagged with codedwire (CW), passive integrated transponder (PIT), radio (RT) telemetry and / or acoustic tags (AT), with survivorship of native brown trout (Salmo trutta) examined in the field. Laboratory results revealed high survivorship following tag attachment / insertion and resumption of feeding within 24-48 h of tagging (all mortalities could be attributed to an unrelated outbreak of fungal infection), with retention rates being high in both pumpkinseed and pikeperch but low in topmouth gudgeon (excluded from field studies). In the field, short-term post-operation survival was high in pikeperch, pumpkinseed and brown trout. In pumpkinseed and trout, 100% of RT fish survived a 24-30 day tracking study, with 60% and 80%, respectively, recaptured alive at least 3 months post-tagging. of PIT tagged pumpkinseed, 44% were recaptured (after 6-18 months), with small-sized, CW-tagged fish (0.38 g weight) captured up to 1 year after tagging. In pikeperch, all AT fish except one (the smallest specimen) survived their full expected tracking period (i.e. tag life) - the single lost specimen survived at least half of its expected tracking period (i.e. 6 month battery life). Overall, the tagging methods used were highly effective in pumpkinseed and pikeperch, showing good retention and survival, but PIT tagging of topmouth gudgeon was plagued by low survivorship and tag rejection. © 2008 Blackwell Munksgaard. Abstract
Scott DM, Rabineau J, Wilson RW, Hodgson DJ, Brown JA
(2008). Can pikeperch colonise new freshwater systems via estuaries? Evidence from behavioural salinity tests. Marine and Freshwater Research
Can pikeperch colonise new freshwater systems via estuaries? Evidence from behavioural salinity tests
Pikeperch (Sander lucioperca) are non-native in the United Kingdom. It is important to understand how environmental factors, such as salinity, influence the behaviour and activity of introduced fish species to identify their dispersal potential. Previous studies have shown that pikeperch, traditionally recognised as a freshwater fish, can tolerate brackish waters and demonstrate physiological acclimation. However, their behavioural responses to brackish waters are unknown. The aim of the present study was therefore to investigate the activity and swimming behaviour of pikeperch obtained from freshwater canals in southern England. In the laboratory, fish were exposed to a 12-h simulated tidal cycle and a 12-day stepped salinity challenge where salinity was increased by 4 every 2 days, up to a salinity of 20. In both regimes, fish showed increased swimming activity in response to increasing salinity, which may represent an avoidance response. The most dramatic changes, including vertical movements, occurred at salinities above ∼16. At these higher salinities, head shaking and coughing behaviours were also observed, suggesting significant stress and respiratory impairment. However, during the simulated tidal cycle, normal behaviour was rapidly restored once salinity was reduced. The results of this study may have implications in understanding the dispersal of non-native fish in the wild. © CSIRO 2008. Abstract
Scott DM, Wilson RW, Brown JA
(2007). Can sunbleak Leucaspius delineatus or topmouth gudgeon Pseudorasbora parva disperse through saline waters?. Journal of Fish Biology
(SUPPL. D), 70-86.
Can sunbleak Leucaspius delineatus or topmouth gudgeon Pseudorasbora parva disperse through saline waters?
In order to determine the potential for the invasive fishes sunbleak Leucaspius delineatus and topmouth gudgeon Pseudorasbora parva to disperse through saline waters their behaviour and physiology were investigated during exposure to salinities of 10.0 and 12.5. Increased salinity caused an increase in whole body cortisol in both species, but sunbleak and topmouth gudgeon showed very different metabolic and behavioural responses to the salinity stress. Sunbleak displayed increased swimming activity in brackish water, which may be important for dispersal through saline waters in the wild, although there were increased metabolic costs associated with this behaviour. Conversely, topmouth gudgeon showed a reduction in both swimming activity and metabolic rate in brackish waters. A pronounced depression in food intake (70-80%) was shown by both species during the salinity exposures. Both sunbleak and topmouth gudgeon, however, showed a full recovery of food intake within 24 h following return to fresh water. Despite the fact that exposure to saline waters is stressful, and affects both physiology and behaviour, rapid recovery of appetite after return to fresh water suggests that short-term use of brackish waters is a feasible dispersal route for sunbleak and topmouth gudgeon in the wild. © 2007 the Fisheries Society of the British Isles. Abstract
Brown, J.A. Wilson, R.W. (2007). The osmoregulatory ability of the European invasive species sunbleak Leucaspius delineatus and topmouth gudgeon Pseudorasbora parva at elevated salinities, and their likely dispersal via brackish waters. Journal of Fish Biology, 70, 1606-1614.
Wilson, R.W. (2007). Three species of fish from an eutrophic, seasonally alkaline lake are not more tolerant to acute high pH exposure in the laboratory. Journal of Fish Biology, 70, 551-566.
Scott DM, Lucas MC, Wilson RW
(2005). The effect of high pH on ion balance, nitrogen excretion and behaviour in freshwater fish from an eutrophic lake: a laboratory and field study. Aquat Toxicol
The effect of high pH on ion balance, nitrogen excretion and behaviour in freshwater fish from an eutrophic lake: a laboratory and field study.
Slapton Ley is a freshwater hyper-eutrophic lake of two basins connected by a narrow channel. One part of the lake experiences summer blooms of cyanobacteria and poor water quality, including elevated water pH (maximum pH recorded=10.54), the other part is shaded by reed beds, and remains clear and neutral. This study used laboratory and field physiological measurements together with radio-tracking to investigate the potential impacts of alkaline pH on the physiology and behaviour of fish from Slapton Ley. Exposure of perch (Perca fluviatilis) from Slapton Ley to pH 9.50 water in the laboratory caused an immediate inhibition of sodium uptake and ammonia excretion to 34 and 32% of control levels, respectively. Net sodium balance recovered by day 3 of exposure whereas ammonia excretion only partially recovered to 60-70% of the control value from 8 h onwards. Urea excretion did not increase as a result of high pH exposure. Fish from the alkaline part of the lake (pH 9.90) had almost three-fold greater plasma ammonia compared to fish from neutral waters, indicating a pronounced disruption of ammonia excretion in the field. There was no significant disturbance to plasma sodium, chloride or total protein in fish sampled from the alkaline water of Slapton Ley. The radio-tracking provided no evidence of adult perch and pike (Esox lucius) trying to seek refuge from the alkaline conditions, despite having access to adjacent parts of the lake with neutral pH. It seems likely that there are advantages (e.g. better foraging, less predation) of withstanding the high pH conditions that outweigh the benefit of moving into more pH neutral parts of the lake. Abstract
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