title: Species-specific ontogenetic diet shifts among Neotropical Crenicichla: using stable isotopes and tissue stoichiometry.
abstract: Ontogenetic diet shifts were compared among five sympatric pike cichlids Crenicichla in a subtropical South American stream using stable C and N isotopes and tissue stoichiometry (C:N). Within species, stable N isotopes were positively related to body size while C:N showed negative relationships. Stable C isotopes, however, were not related to body size in any species. By modelling the switch to piscivory using gut content-isotope-body size relationships, diet shifts were shown to be species-specific with regard to both rate and degree of piscivory. Compared to other piscivorous lineages, Crenicichla appear to be unusually small-bodied (based on maximum body size). Because of their diversity, abundance and dynamic size-structured functional roles, Crenicichla may exert broad and complex predation pressures on the aquatic community.
authors.affiliation: Biology Department, Appalachian State University, Boone, NC 28608, USA. edb0014@auburn.edu
authors.forename: E D
authors.initials: ED
authors.lastname: Burress
authors.forename: A
authors.initials: A
authors.lastname: Duarte
authors.forename: W S
authors.initials: WS
authors.lastname: Serra
authors.forename: M M
authors.initials: MM
authors.lastname: Gangloff
authors.forename: L
authors.initials: L
authors.lastname: Siefferman
mesh_terms: D000818:Animals; D044822:Biodiversity; D049628:Body Size; D002247:Carbon Isotopes; D023681:Cichlids / Q000033:anatomy & histology / Q000502:physiology*; D004032:Diet; D005247:Feeding Behavior; D009587:Nitrogen Isotopes; D011157:Population Dynamics; D011235:Predatory Behavior; D013045:Species Specificity
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes