Angling baits and invasive crayfish as important trophic subsidies for a large cyprinid fish

Show simple item record Basic, Tea Britton, J. Robert Jackson, Michelle C. Reading, Peter Grey, Jonathan 2015-03-09T12:19:48Z 2015-03-09T12:19:48Z 2015-01
dc.description.abstract Invasive species and anthropogenic sources of allochthonous trophic subsidies can have substantial eco-logical consequences for freshwater ecosystems, including modifying the diet of consumers and altering food web structure. Here, the diet of an omnivorous cyprinid fish, European barbel Barbus barbus, was assessed in relation to the presence of invasive signal crayfish Pacifastacus le-niusculus and pelletized fish-meal in four rivers in England. Pellets are often used in large quantities by river anglers and thus could provide an important trophic subsidy, not only to the fish but also indirectly via P. leniusculus. Carbon and nitrogen stable isotopes were used to estimate the proportion of diet assimilated from natural sources and from P. leniusculus and pellets by B. barbus of lengths between 420 and 800 mm. Pellets generally made a large contribution to the overall biomass of B. barbus (up to 59 % of population diet) and in the two rivers where they were present, P. leniusculus were also an important resource (up to 30 % of population diet). The proportion derived from macro-invertebrates (excluding P. leniuscu-lus) was substantially lower. Stable isotope mixing models further demonstrated considerable intraspecific variability in B. barbus diet within the rivers, with pellets comprising up to 79 % of the biomass of individual B. barbus in rivers where P. leniusculus was absent. Where present, P. le-niusculus effectively replaced and thus reduced the contribution of pellets to individual fish diet. Thus, isotopic evidence from three of the four rivers indicates that B. barbus populations are heavily reliant ([50 %) upon angler-introduced baits that act as an important allochtho-nous subsidy and will also prey upon invasive P. leniusculus where they are present. en_ZA
dc.description.embargo 2016-01-31 en_ZA
dc.description.librarian hb2015 en_ZA
dc.description.uri en_ZA
dc.identifier.citation Basic, T, Britton, J, Jackson, MC, Reading, P & Grey, J 2015, 'Angling baits and invasive crayfish as important trophic subsidies for a large cyprinid fish', Aquatic Sciences, vol. 77, no. 1, pp. 153-160. en_ZA
dc.identifier.issn 1015-1621 (print)
dc.identifier.issn 1420-9055 (online)
dc.identifier.other 10.1007/s00027-014-0370-7
dc.language.iso en en_ZA
dc.publisher Springer en_ZA
dc.rights © Springer Basel 2014. The original publication is available at : http://link.springer.comjournal/27 en_ZA
dc.subject Allochthonous en_ZA
dc.subject Barbel en_ZA
dc.subject Fishmeal en_ZA
dc.subject Signal crayfish en_ZA
dc.subject Stable isotopes en_ZA
dc.title Angling baits and invasive crayfish as important trophic subsidies for a large cyprinid fish en_ZA
dc.type Postprint Article en_ZA

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