A test of the senses: Fish select novel habitats by responding to multiple cues

Abstract

Abstract. Habitat-specific cues play an important role in orientation for animals that move through a mosaic of habitats. Environmental cues can be imprinted upon during early life stages to guide later return to adult habitats, yet many species must orient toward suitable habitats without previous experience of the habitat. It is hypothesized that multiple sensory cues may enable animals to differentiate between habitats in a sequential order relevant to the spatial scales over which the different types of information are conveyed, but previous research, especially for marine organisms, has mainly focused on the use of single cues in isolation. In this study, we investigated novel habitat selection through the use of three different sensory modalities (hearing, vision, and olfaction). Our model species, the French grunt, Haemulon flavolineatum, is a mangrove/seagrass-associated reef fish species that makes several habitat transitions during early life. Using several in situ and ex situ experiments, we tested the response of fish toward auditory, olfactory, and visual cues from four different habitats (seagrass beds, mangroves, rubble, and coral reef ). We identified receptivity to multiple sensory cues during the same life phase, and found that different cues induced different reactions toward the same habitat. For example, early-juvenile fish only responded to sound from coral reefs and to chemical cues from mangroves/seagrass beds, while visual cues of conspecifics overruled olfactory cues from mangrove/seagrass water. Mapping these preferences to the ecology of ontogenetic movements, our results suggest sequential cue use would indeed aid successful orientation to novel key habitats in early life.

Brain lateralization involved in visual recognition of conspecifics in coral reef fish at recruitment

“…Correct habitat identification depends strongly on the ability of marine larvae to recognize and respond to sensory signals from conspecifics, habitat components and predators (Barth et al, 2015). Many coral reef fish species recognize their conspecifics using visual cues (Huijbers et al, 2012;Lecchini, Peyrusse, Lanyon, & Lecellier, 2014;O'Connor et al, 2015). Despite the importance of visual, acoustic and chemical cues during the recruitment process (Leis et al, 2011), very little information is available on the relationship between brain morphology or lateralization and the behavioural and social interactions of coral reef fishes (Barth et al, 2015).…”

Orientation from open water to settlement habitats by coral reef fish: behavioral flexibility in the use of multiple reliable cues

“…While it is known that some fishes are attracted to the smell of mixed water bodies from seagrass habitats (Arvedlund & Takemura 2006, Huijbers et al 2012, studies typically did not evaluate which potential cues of animals or plants living in seagrass ecosystems could be responsible for this. The mecha- nisms to achieve successful orientation to early life stage habitats are still poorly understood, especially for fishes that recruit to non-reef environments.…”

“…In the absence of visual habitat cues at larger distances offshore, a preference for seagrass habitat water over coral reef or mangrove habitat water can act as a coarse, but reliable cue for offshore pelagic larvae to navigate towards coastal habitats from the open ocean. Based on experiments using auditory, olfactory, and visual cues, Huijbers et al (2012) proposed that larvae of fishes that are associated with mangroves and seagrass as juveniles use reef sounds for long-distance navigation from the open ocean towards coastal reefs, switch to olfactory cues closer to shore, and then use visual cues when settling to the benthos. Based on our findings we suggest that when pelagic larvae are approaching coastal environments, seagrass leaves and resident conspecifics could provide important chemical cues at smaller spatial scales that would enable larvae to more accurately navigate towards specific profitable areas within lagoons or estuaries during the final stage of settlement or directly afterwards.…”

“…For settlement-stage larvae of marine organisms that are completing their oceanic life stage, the foremost important activity is to orientate to and locate an optimal benthic habitat. Chemical and auditory cues may play an important role for orientation during this process (Atema et al 2002, Huijbers et al 2012.…”

“…For example, reef species that are associated with mangroves and seagrass beds during only their early life stage need to navigate as larvae from the open ocean, across coastal shelves that harbor coral reefs, towards bays or lagoons that harbor juvenile habitats (Pollen et al 2007, Pollux et al 2007. Potentially, larvae of such species consecutively use auditory, olfactory, and visual cues to navigate from the open ocean towards their settlement habitats (Huijbers et al 2012). The settlement stage is usually short and lasts a few days at most (Milicich & Doherty 1994), as larvae are extremely vulnerable to predation when they arrive near shore and have to pass through a 'wall of mouths' formed by coastal predators (Hamner et al 1988, McCormick & Kerrigan 1996, McCormick & Holmes 2006.…”