Shifts of Sensory Modalities in Early Life History Stage Estuarine Fishes (Sciaenidae) from the Chesapeake Bay Using X-ray Micro Computed Tomography

• Published in: Environmental Biology of Fishes
• Main Authors: Deary, Alison L., Metscher, Brian, Brill, Richard W., Hilton, Eric J.
• Format: Text
• Language: unknown
• Published: The Aquila Digital Community 2016
• Subjects: Drums; Ecomorphology; Ontogeny; Larvae; Foraging habitat; Brain; Sciaenops ocellatus
• Online Access: https://aquila.usm.edu/fac_pubs/17507; https://doi.org/10.1007/s10641-016-0479-8

Increases in human populations along coasts have altered the estuarine nursery habitats that are important for many aquatic organisms. These perturbations include changes to the sensory environment due to increased turbidity resulting from runoff and nutrient loading; these changes are occurring faster than fish species can become adapted to the new prevailing conditions. However, understanding how modifications to the sensory environment impacts fishes during early life history stages (ELHS) requires understanding the senses used to locate food and evade predators and how they change during ontogeny. The drums (Sciaenidae) exhibit substantial morphological diversity in their peripheral sense organs as adults. We, therefore, used the relative volumes of their brain structures to assess ontogenetic changes in the sensory modalities of sciaenid species from different foraging guilds. Early stage sciaenids were imaged using X-ray micro computed tomography. The optic tract was the largest sensory region, suggesting that vision is the primary sensory modality in sciaenids, regardless of size, species, or foraging habitat. There were differences in the relative proportions of the other sensory areas according to foraging guild. These differences suggest that Cynoscion nebulosus (a pelagic forager) relies on audition and mechanoreception through ontogeny to augment vision, whereas Sciaenops ocellatus (a generalist forager) uses olfaction, audition, and mechanoreception. In contrast, Leiostomus xanthurus (a benthic forager) relies on olfaction and gustation. We propose that the ontogenetic trends in sensory modality described in sciaenids from the Chesapeake Bay (USA) can be used in future research to ascertain the potential species-specific impacts of water quality change on ELHS fishes.