Cormorant catch concerns for fishers: estimating the size-selectivity of a piscivorous bird

• Published in: PloS one 2013-11, Vol.8 (11), p.e77518-e77518
• Main Authors: Troynikov, Vladimir, Whitten, Athol, Gorfine, Harry, Pūtys, Zilvinas, Jakubavičiūtė, Eglė, Ložys, Linas, Dainys, Justas
• Format: Article
• Language: English
• Subjects: Animals; Birds; Birds - physiology; Commercial fishing; Competition; Cormorants; Diet; Dynamic tests; Estimates; Estimation; Feeding Behavior - physiology; Fish; Fish populations; Fisheries; Fisheries management; Fishing; Fishing equipment; Growth models; Laboratories; Lithuania; Marine ecology; Models, Biological; Perca fluviatilis; Perches; Phalacrocoracidae; Phalacrocorax carbo; Population; Population biology; Population Dynamics; Predation; Predators; Selectivity; Size estimation; Zoology
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0077518

Conflict arises in fisheries worldwide when piscivorous birds target fish species of commercial value. This paper presents a method for estimating size selectivity functions for piscivores and uses it to compare predation selectivities of Great Cormorants (Phalacrocorax carbo sinensis L. 1758) with that of gill-net fishing on a European perch (Perca fluviatilis L. 1758) population in the Curonian Lagoon, Lithuania. Fishers often regard cormorants as an unwanted "satellite species", but the degree of direct competition and overlap in size-specific selectivity between fishers and cormorants is unknown. This study showed negligible overlap in selectivity between Great Cormorants and legal-sized commercial nets. The selectivity estimation method has general application potential for use in conjunction with population dynamics models to assess fish population responses to size-selective fishing from a wide range of piscivorous predators.