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Use of an encounter model to predict size‐selective predation by a stream‐dwelling cyprinid
Author(s) -
RINCÓN PEDRO A.,
LOBÓNCERVIÁ JAVIER
Publication year - 1995
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.1995.tb01159.x
Subject(s) - predation , benthic zone , rutilus , benthos , biology , ecology , limanda , range (aeronautics) , piscivore , fish <actinopterygii> , predator , fishery , materials science , flatfish , composite material
SUMMARY 1. The increased probability of detection of larger prey in the drift appeared to be the major determinant of prey consumption by red roach ( Rutilus arcasi ) in an Iberian stream. We developed a model of prey encounter incorporating this factor that explained 68% of the overall variation in the consumption of prey of different size. When the same model was applied to benthic size distributions the variance explained was 16%. 2. Gape‐limited ingestion also was a significant factor influencing prey consumption and, when added to the model, the variance explained increased to 85% (32% for the benthos), but its importance was strongly dependent on both: (i) the maximum prey size available and (ii) fish size. 3. The exact shape of red roach reactive fields and, as a consequence, their degree of size‐selectivity appeared to vary seasonally and ontogenetically. In summer, younger fish exhibited apparently reduced reactive fields. We hypothesize that this can be the result of factors such as microhabitat shifts or a reduced range of prey sizes.