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

Abstract

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

Behavioral responses of two deep-sea fish species to red, far-red, and white light

“…In the adult stages of life, certain macrourid species likely rely on olfaction and mechanoreception to find food sources and possibly use vision to find mates or, to a lesser extent, food (Wagner 2002(Wagner , 2003. Bailey et al (2007) suggested that grenadiers use olfaction to locate food sources from a distance, but rely on gustation and mechanoreception at close ranges to the source. It is possible that vision plays a minor role in the feeding ecology of adult C. acrolepis.…”

Effects of the long-term anosmia combined with vision deprivation on the taste sensitivity and feeding behavior of the rainbow trout Parasalmo (=Oncorhynchus) mykiss

“…In the fish having external taste buds, an irreversible ablation of olfactory receptors causes only a transient loss of sensitivity to feed signal sub stances dissolved in water; 2-3 months later, the fish restore the ability to search for remote sources of food chemical signals (Kasumyan and Marusov, 2002Marusov and Kasumyan, 2010). First and foremost, the presence of external taste buds is characteristic of nocturnal fish and fish inhab iting benthic and near benthic biotopes and feeding mainly on benthic organisms (Kapoor et al, 1975;Ovalle and Shinn, 1977;Atema, 1980;Pevzner, 1981Pevzner, , 1985Devitsina and Kazhlaev, 1992;Lombarte and Aquirre, 1997;Harvey and Batty, 2002;Bailey et al, 2007). The more pronounced a benthic life habit and benthic feeding, the larger fish body areas are covered with external taste buds and the higher is their total number (Gomahr et al, 1992).…”

A review of the sensory biology of chimaeroid fishes (Chondrichthyes; Holocephali)

“…The inclusion of data for chimaeroids into pre-existing large, comparative elasmobranch datasets such as those that exist for eye size and the morphology of the olfactory system (Schluessel et al 2008) and the inner ear (Evangelista et al 2010) may prove particularly fruitful and would allow sensory system ecomorphology to be assessed within a phylogenetic context. It may also be possible to combine anatomical information with behavioural observations and experiments conducted using landers as has been done to investigate the role of taste and tactile senses in search behaviour in deep-sea fishes (Bailey et al 2007). …”