Aug 27, 2008 - within the shelf of the ArgentineâUruguayan Com- mon Fishing Zone (AUCFZ). However, changes on S. guggenheim trophic level with growth ...
Environ Biol Fish (2009) 84:41–52 DOI 10.1007/s10641-008-9387-x
Changes in trophic level of Squatina guggenheim with increasing body length: relationships with type, size and trophic level of its prey Rodolfo Vögler & Andrés C. Milessi & Luis O. Duarte Received: 9 April 2007 / Accepted: 24 July 2008 / Published online: 27 August 2008 # Springer Science + Business Media B.V. 2008
Abstract The occurrence of changes in the trophic level (TL) of sharks with growth has not been quantified until now. Here length-related changes on Squatina guggenheim Marini trophic level were determined, and shifts in type, size and trophic level of its prey were analysed. Sampling took place during five bottom trawl surveys conducted in the Argentine– Uruguayan Common Fishing Zone during spring (December/1995, October/1997) and fall (March/ 1997, March–April/1998, May–June/1998), using an Engel bottom-trawl net to capture the sharks. Three length groups were defined based on diet composition and using a cluster analysis (group I, 23–60 cm; group II, 61–80 cm; group III, 81–91 cm LT). An ANOSIM procedure detected significant differences (P
