Feeding habits, seasonal and ontogenetic diet shift of blacktail comber, Serranus atricauda (Pisces: Serranidae), from the Azores, north-eastern Atlantic Telmo Morato a,* , Ricardo Serra Äo Santos a , Jose  Pedro Andrade b a Departamento de Oceanogra®a e Pescas, Universidade dos Ac Ëores, PT-9901-862 Horta, Portugal b CCMar, Universidade do Algarve, Campus de Gambelas, PT-8000-810 Faro, Portugal Received 6 September 1999; received in revised form 1 February 2000; accepted 10 February 2000 Abstract The stomach contents of 422 Serranus atricauda, sampled between June 1993 and September 1994 in the Azores (north- eastern Atlantic), were examined. Fishes and crustaceans were the main contents with gastropods, bivalves and salps uncommon. Mysids (Siriella jaltensis) and Tripterygion delaisi were the most frequent prey items followed by Capros aper, Parablennius spp., Alpheus spp. and Xantho sp. The type and quantity of food ingested changed over season. S. atricauda are generalists that can feed opportunistically on alternative prey. They are diurnal predators. Ontogenetic differences were found in the diet composition and feeding activity within the range of sizes studied. There was a signi®cant positive relation between mean prey width and predator size. # 2000 Elsevier Science B.V. All rights reserved. Keywords: Stomach contents; Blacktail comber; Serranus atricauda; Seasonal changes; Diel patterns; Ontogenetic changes 1. Introduction Serranids are carnivorous ®shes that live near the bottom in littoral and sub-littoral zones of tropical and temperate seas. They play an important role in coastal marine ecosystems where they are active predators of a number of ®shes, crustaceans and cephalopods (Heemstra and Randall, 1993; Tuset et al., 1996; Labropoulou and Eleftheriou, 1997; Barreiros and Santos, 1998). Blacktail comber , Serranus atricauda (Gu Ènther, 1874), is a serranid ®sh that lives on rocky bottoms, from the shallow subtidal down to about 90 m depth. Its distribution extends from the Bay of Biscay (north-eastern Atlantic) southward to Maur- itania and around the Azores, Madeira and Canaries archipelagos, the Mediterranean coast of Morocco, Algeria, southern Spain, and occasionally southern France (Tortonese, 1986). Blacktail comber is a her- maphrodite, which in the Azores matures at about 250 mm total length (TL) and spawns from July to September (Lourinho, 1998). Maturation length cor- responds to about 4 years of age (Costa, 1997). Around the Azores there is considerable recrea- tional and semi-subsistence ®shing with rod and line or handline from the shore and close inshore from small boats, as well as considerable use of coastal nets and spear-®shing activity (Santos et al., 1995). Black- tail comber is one of the serranids targeted by these ®sheries. In spite of its relative abundance and impor- tance to ®sheries, information on the biology and Fisheries Research 49 (2000) 51±59 * Corresponding author. Tel.: 351-292-292-988; fax: 351-292-292-659. E-mail address: telmo@dop.uac.pt (T. Morato). 0165-7836/00/$ ± see front matter # 2000 Elsevier Science B.V. All rights reserved. PII:S0165-7836(00)00189-2