Capture Success and Diet of Cottid Fishes: The Role of Predator Morphology and Attack Kinematics

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Ecological Society of America is collaborating with JSTOR to digitize, preserve and extend access to Ecology.Abstract. In this study laboratory experiments were conducted to test predictions of capture performance based on an understanding of the hydrodynamics of contrasting feeding modes (ram and suction feeding) and on an observed ecomorphological pattern among marine members of the temperate fish family Cottidae. Small-mouthed species that feed predominately on grasping prey (e.g., crabs, isopods, gastropods) were predicted to have low capture success on an elusive prey (shrimp) and to use kinematics more consistent with suction-feeding mechanisms; large-mouthed species that feed predominately on elusive prey (e.g., fishes, shrimp) were predicted to have high capture success in attacks on shrimp and to use ram-feeding kinematics. Laboratory experiments in which predators were videotaped in attacks on either hippolytid shrimp or cancrid crabs tested both the attack success and kinematic predictions.Small-mouthed cottid species had significantly lower attack success on shrimp (20-4 1% vs. 45-56%) than did large-mouthed cottids. Both groups had similar high success rates in attacks on crabs on a sand surface: 93-100% for small-mouthed species and 85-95% for large-mouthed species. Most small-mouthed cottids used attack kinematics more typical of suction feeding (e.g., shorter predator-prey distances and slower attack velocities) than did ram feeders. One small-mouthed species, Jordania zonope, used attack kinematics similar to those used by large-mouthed cottids in attacks on shrimp, and had higher capture success than other small-mouthed species, but had significantly lower capture success than large-mouthed species. All predators showed some ability to modify their attack kinematics when attacking prey with different escape tactics, but cottids showed little intraspecific variation in attack kinematics, in contrast to several recent studies of the strike mechanics of lower vertebrates.These results emphasize the importance of both mouth morphology and attack kinematics in determining interspecific differences in capture success and, perhaps, diet. The success of the simple predictions presented here provides hope that general predictions of foraging ecology may be derived from morphological patterns when the prey are treated not by their taxonomic affinities but by the functional demands they make on their predators. The study of the influence of form on the trophic biology of fishes has been an active area of researchfor over twenty years. The pioneering work of Keast and Webb (1966) demonstrated clear relationships between patterns of variation in mouth and locomotory structur...

Functional morphology of feeding in the scale-eating specialistCatoprion mento

“…Most fishes possess the ability to modify feeding behavior and kinematics of the strike according to the evasiveness of the prey (Liem, 1978(Liem, , 1979Vinyard, 1982;Sanderson, 1990;Norton, 1991;Nemeth, 1997b), as well as size of the prey (Lauder, 1981;Ferry-Graham, 1997) and position of the prey in the water column (Lauder, 1981). Among those fishes able to modulate feeding behavior, without exception, more evasive prey elicit faster strikes with greater displacement of the cranial J. Janovetz .…”

The benefits of planar circular mouths on suction feeding performance

“…This type of mouth opening is achieved by a combination of jaw kinesis and membranes in teleosts, while in many tetrapods and cartilaginous fishes, labial cartilages or membranes fill the lateral margins of the mouth as it opens [4][5][6]. It is thought that a planar mouth opening enhances suction feeding hydrodynamics by allowing more efficient flow of water into the mouth [4,7,8] and by preventing flow that is directed orthogonal to the direction of the prey item. During a suction feeding event, the predator has a fixed expansion volume that generates the water flow entering the mouth.…”

Trophic ecomorphology of cardinalfish

“…Such studies have identified predictive relationships between fish form and patterns of prey use (Norton 1991, Winemiller 1991, Wainwright & Richard 1995. Morphological form has been intuitively linked to function for a long time (Bock & Wahlert 1965).…”