Post-metamorphic Feeding in Lampreys

Abstract

Eighteen of 41 lamprey species worldwide feed post metamorphosis; nine in either marine waters or fresh waters and nine exclusively in fresh waters. Four feeding modes have been identified: blood feeding, flesh feeding, blood and flesh feeding, and carrion feeding. Adaptations to these feeding modes are associated with characteristics of the dentition of the oral disc and tongue-like piston, the oral papillae and fimbriae, the velar tentacles, and the buccal glands. The duration of the adult feeding phase varies from a few months to 4 years and during this time the various species grow either slightly or up to nearly eight times the length that they reached as larvae. The post-metamorphic diet consists usually of fishes but in some cases may include marine mammals. Feeding behavior is complex and highly variable and differs between the two major modes of blood feeding and flesh feeding. Blood feeders tend to selectively attack larger hosts and tend to attach ventrally to them in deep water but dorsally in shallower habitats. Flesh feeders tend to attach dorso-laterally to schooling fishes, and their hosts may be relatively small compared to those used by blood feeders.