Robert E. Hueter

Bio: Robert E. Hueter is an academic researcher from Mote Marine Laboratory. The author has contributed to research in topics: Perspective (graphical) & Negaprion brevirostris. The author has an hindex of 3, co-authored 5 publications receiving 161 citations.

Adaptations for spatial vision in sharks

Abstract: The revelation that sharks as a group are not simply all-rod, nocturnal vertebrates has called for a new perspective on their spatial visual capabilities Using the lemon shark (Negaprion brevirostris) as a model species, selected components of spatial vision in sharks have been investigated The physiological optics of the eye have been modeled with a schematic eye for the lemon shark, the first such model for an elasmobranch species Retinal cone and ganglion cell topography and retinotectal projection pattern have been mapped completely for the first time in an elasmobranch These topographic maps reveal a prominent visual streak, a functional specialization that is correlated with the lemon shark's visual behavior and habitat Evidence in the literature of similar specializations for spatial vision in other elasmobranchs signifies that the lemon shark is not a special case Assessments of the quality of shark vision should consider the sensory niches of these animals in their specific marine environments, as well as the phylogenetic and ontogenetic diversity within the group

The Vertebrate Eye and Its Adaptive Radiation.

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Characteristic Sizes of Life in the Oceans, from Bacteria to Whales*

Abstract: The size of an individual organism is a key trait to characterize its physiology and feeding ecology. Size-based scaling laws may have a limited size range of validity or undergo a transition from one scaling exponent to another at some characteristic size. We collate and review data on size-based scaling laws for resource acquisition, mobility, sensory range, and progeny size for all pelagic marine life, from bacteria to whales. Further, we review and develop simple theoretical arguments for observed scaling laws and the characteristic sizes of a change or breakdown of power laws. We divide life in the ocean into seven major realms based on trophic strategy, physiology, and life history strategy. Such a categorization represents a move away from a taxonomically oriented description toward a trait-based description of life in the oceans. Finally, we discuss life forms that transgress the simple size-based rules and identify unanswered questions.

A review of the biology, fisheries and conservation of the whale shark Rhincodon typus.

Abstract: Although the whale shark Rhincodon typus is the largest extant fish, it was not described until 1828 and by 1986 there were only 320 records of this species. Since then, growth in tourism and marine recreation globally has lead to a significant increase in the number of sightings and several areas with annual occurrences have been identified, spurring a surge of research on the species. Simultaneously, there was a great expansion in targeted R. typus fisheries to supply the Asian restaurant trade, as well as a largely un-quantified by-catch of the species in purse-seine tuna fisheries. Currently R. typus is listed by the IUCN as vulnerable, due mainly to the effects of targeted fishing in two areas. Photo-identification has shown that R. typus form seasonal size and sex segregated feeding aggregations and that a large proportion of fish in these aggregations are philopatric in the broadest sense, tending to return to, or remain near, a particular site. Somewhat conversely, satellite tracking studies have shown that fish from these aggregations can migrate at ocean-basin scales and genetic studies have, to date, found little graphic differentiation globally. Conservation approaches are now informed by observational and environmental studies that have provided insight into the feeding habits of the species and its preferred habitats. Notwithstanding these advances, there remain notable gaps in the knowledge of this species particularly with respect to the life history of neonates and adults who are not found in the feeding aggregations.

Behavioural ecology and retinal cell topography

Abstract: The vertebrate retina is an extension of the brain, a hemisphere of neural tissue upon which is mapped an image of a particular species visual environment. Each point in visual space is subtended by a corresponding point on the neural retina which in turn is retinotopically mapped onto the visual centres of the brain. Light energy or the ‘optical image’ is transformed into electrical energy or a ‘neural image’ by the photoreceptors and, via a number of interneurons (bipolar, amacrine and horizontal cells), these signals reach the ganglion cells each of which possess an axon carrying information to the central nervous system via the optic nerve. Although processing at the level of the photoreceptors may not necessarily change the neural image, due to the over abundance of photoreceptors relative to the number of ganglion cells, it is the ganglion cells which ultimately define the perception of a species’ environment received by the central nervous system.