A taste of the deep-sea: The roles of gustatory and tactile searching behaviour in the grenadier fish Coryphaenoides armatus

摘要: The deep-sea grenadier fishes (Coryphaenoides spp.) are among the dominant predators and scavengers in ocean basins that cover much of Earth's surface. Baited camera experiments were used to study behaviour these fishes. Despite apparent advantages rapidly consuming food, grenadiers attracted bait spend a large proportion their time prolonged periods non-feeding activity. Video analysis revealed fish often adopted head-down swimming attitude (mean 21.3° between seafloor), with velocity negatively related attitude. also swam around along vertical horizontal structures lander head immediately adjacent structure. We initially hypothesised this was associated use short chin barbel foraging. Barbel histology showed numerous taste buds skin, nerve about 20,000 axons adult fish. A tracing experiment one undamaged animal termination fields neurons trigeminal rhombencephalic regions, indicating both mechanoreceptory gustatory role for barbel. Our conclusion olfactory foraging becomes ineffective at close ranges is followed by search phase using tactile sensing development sensory method probably co-evolved alongside behavioural changes mechanics allow postural stability low speeds.