The wels catfish Silurus glanis has been constantly spreading in many European basins, outside its native range. Being a voracious predator, it is considered to have a severe impact on local fish communities. In the Ticino River (Northern Italy), bones of S. glanis were found in feces from the top predator Lutra lutra. To estimate the control capability of L. lutra for this species and to backcalculate S. glanis’ size from its bone remains, whole skeletons from 27 differently sized S. glanis specimens were analyzed. A double pharyngeal element and all caudal vertebrae emerged as significant items for species identification. The mean length of the pharyngeal element was directly related to fish mass, while for vertebrae, a K‐index was proposed to identify the position of each vertebra along the spine and, from this, to calculate the original fish mass. This methodology allowed us to establish that the length of the preyed S. glanis was 85–435 mm, and the ages were between 0+ and 2+ years. The proposed methodology opens new perspectives for more detailed studies on the efficiency of predation by piscivorous species on allochthonous ones.

Back‐Calculation of Fish Size in Diet Analysis of Piscivorous Predators: A New Index for the Alien Silurus glanis / R. Bacchetta, A. Marotta, A. Nessi, P.C.M. Tremolada. - In: SUSTAINABILITY. - ISSN 2071-1050. - 13:8(2021 Apr 13). [10.3390/su13084322]

Back‐Calculation of Fish Size in Diet Analysis of Piscivorous Predators: A New Index for the Alien Silurus glanis

R. Bacchetta
Primo
;
P.C.M. Tremolada
Ultimo
2021

Abstract

The wels catfish Silurus glanis has been constantly spreading in many European basins, outside its native range. Being a voracious predator, it is considered to have a severe impact on local fish communities. In the Ticino River (Northern Italy), bones of S. glanis were found in feces from the top predator Lutra lutra. To estimate the control capability of L. lutra for this species and to backcalculate S. glanis’ size from its bone remains, whole skeletons from 27 differently sized S. glanis specimens were analyzed. A double pharyngeal element and all caudal vertebrae emerged as significant items for species identification. The mean length of the pharyngeal element was directly related to fish mass, while for vertebrae, a K‐index was proposed to identify the position of each vertebra along the spine and, from this, to calculate the original fish mass. This methodology allowed us to establish that the length of the preyed S. glanis was 85–435 mm, and the ages were between 0+ and 2+ years. The proposed methodology opens new perspectives for more detailed studies on the efficiency of predation by piscivorous species on allochthonous ones.
invasive species; Lutra lutra; diet analysis; bone remains; fish mass quantification; spraint analysis;
Settore BIO/07 - Ecologia
Settore BIO/06 - Anatomia Comparata e Citologia
Settore BIO/05 - Zoologia
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/835064
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