Feeding habits of the albacore tuna Thunnus alalunga (Perciformes, Scombridae) from central Mediterranean Sea

• Published in: Marine biology 2008-07, Vol.155 (1), p.113-120
• Main Authors: Consoli, P., Romeo, T., Battaglia, P., Castriota, L., Esposito, V., Andaloro, F.
• Format: Article
• Language: English
• Subjects: Agnatha. Pisces; Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; Biomedical and Life Sciences; Brachyscelus crusculum; Confidence intervals; Crustaceans; Data collection; Diet; Euthynnus alletteratus; Fish; Fishing; Freshwater & Marine Ecology; Fundamental and applied biological sciences. Psychology; Heteroteuthis dispar; Life Sciences; Marine; Marine & Freshwater Sciences; Marine biology; Microbiology; Oceanography; Original Paper; Paralepis coregonoides; Paralepis speciosa; Phrosina semilunata; Prey; Sample size; Sarda sarda; Scombridae; Sea water ecosystems; Surface water; Synecology; Thunnus alalunga; Thunnus thynnus; Trophic levels; Tuna; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Xiphias gladius; Zoology
• ISSN: 0025-3162; 1432-1793
• DOI: 10.1007/s00227-008-1012-1

In order to assess feeding habits and trophic level of this species, we analysed the stomach content of 189 specimens collected monthly in the southern Tyrrhenian Sea (central Mediterranean Sea). The results showed that this species is a pelagic predator focusing on paralepidid fish and, more in detail, on two species such as Paralepis speciosa and Paralepis coregonoides . Among cephalopods, Heteroteuthis dispar was the most abundant prey item in the stomach contents, whereas among crustaceans the hyperidean amphipods Phrosina semilunata and Brachyscelus crusculum were the most representative species. In the present study, the diet of the albacore did not vary significantly throughout the period of study focusing, in the different season of catch, on the same prey species. Not even a size-related diet shift was observed, with a partitioning of the albacore sample into five size groups. Levin’s standardized index showed a low value indicating a limited trophic niche width, with a diet dominated by a limited number of taxa and then a specialist behaviour for this predator. The estimated TROPH value for T. alalunga resulted very similar to that calculated in Mediterranean Sea for other species as well as Xiphias gladius, Thunnus thynnus, Euthynnus alletteratus and Sarda sarda . Then, the albacore tuna can be considered as a top carnivore.