Mouth Allometry and Feeding Habits of Some Mediterranean Fishes

Abstract

Feeding habits, diet composition, and food consumption in fishes have been related to various morphological characteristics notably the mouth (e.g., Karpouzi and Stergiou 2003), gut length (Kapoor et al. 1975, Kramer and Bryant 1995, Karachle and Stergiou 2010) and tail (Palomares and Pauly 1989, 1998, Pauly 1994, Karachle 2008). In particular, mouth shape and position, dentition, branchial spines (in terms of structure and number) and distance between gill rakers, and pharyngeal bone structure are strongly connected to species’ feeding and diet composition (Al-Hussaini 1947, Verigina 1991, Wootton 1998, Boyle and Horn 2006). Mouth gape is considered as an important, yet restraining, factor for food selection, capture, handling, and consumption (Keast and Webb 1966, Kapoor et al. 1975, Wainwright and Richard 1995, Karpouzi and Stergiou 2003, Makrakis et al. 2008, Goatley and Bellwood 2009). As fish grow, they tend to prey upon a greater size range of food items, and the mean size of the prey consumed increases, a fact more evident in second order carnivores and apex predators (Scharf et al. 2000, 2009, Stergiou and Karpouzi 2002, Karpouzi and Stergiou 2003, Arim et al. 2010). Such an increase in prey-size consumed is generally attributed to both morphological (e.g., ontogenetic mouth size increase) and physiological factors (e.g., vision acuity, increasing swimming ability), that allow predators to consume larger prey (Keast and Webb 1966, Kaiser and Hughes 1993, Juanes 1994, Juanes and Conover 1994, Hart 1997, Wootton 1998, Fordham and Trippel 1999). Therefore, and especially in carnivorous fishes, mouth shape and size can be used for the explanation of interACTA ICHTHYOLOGICA ET PISCATORIA (2011) 41 (4): 265–275 DOI: 10.3750/AIP2011.41.4.02