Sensory Biology Research Papers - Academia.edu (original) (raw)

Incidental capture, or bycatch, in fisheries represents a substantial threat to the sustainability of elasmobranch populations
worldwide. Consequently, researchers are increasingly investigating elasmobranch bycatch reduction methods, including
some focused on these species’ sensory capabilities, particularly their electrosensory systems. To guide this research, we
review current knowledge of elasmobranch sensory biology and feeding ecology with respect to fishing gear interactions and
include examples of bycatch reduction methods used for elasmobranchs as well as other taxonomic groups. We discuss potential
elasmobranch bycatch reduction strategies for various fishing gear types based on the morphological, physiological, and
behavioural characteristics of species within this diverse group. In select examples, we indicate how an understanding of the
physiology and sensory biology of vulnerable, bycatch-prone, non-target elasmobranch species can help in the identification
of promising options for bycatch reduction. We encourage collaboration among researchers studying bycatch reduction
across taxa to provide better understanding of the broad effects of bycatch reduction methods.

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- Sensory Biology

Several factors that influence the evolution of the unusual head morphology of hammerhead sharks (family Sphyrnidae) are
proposed but few are empirically tested. In this study we tested the ‘enhanced binocular field’ hypothesis (that proposes
enhanced frontal binocularity) by comparison of the visual fields of three hammerhead species: the bonnethead shark, Sphyrna
tiburo, the scalloped hammerhead shark, Sphyrna lewini, and the winghead shark, Eusphyra blochii, with that of two carcharhinid
species: the lemon shark, Negaprion brevirostris, and the blacknose shark, Carcharhinus acronotus. Additionally, eye rotation
and head yaw were quantified to determine if species compensate for large blind areas anterior to the head. The winghead shark
possessed the largest anterior binocular overlap (48deg.) and was nearly four times larger than that of the lemon (10deg.) and
blacknose (11deg.) sharks. The binocular overlap in the scalloped hammerhead sharks (34deg.) was greater than the bonnethead
sharks (13deg.) and carcharhinid species; however, the bonnethead shark did not differ from the carcharhinids. These results
indicate that binocular overlap has increased with lateral head expansion in hammerhead sharks. The hammerhead species did
not demonstrate greater eye rotation in the anterior or posterior direction. However, both the scalloped hammerhead and
bonnethead sharks exhibited greater head yaw during swimming (16.9deg. and 15.6deg., respectively) than the lemon (15.1deg.)
and blacknose (15.0deg.) sharks, indicating a behavioral compensation for the anterior blind area. This study illustrates the larger
binocular overlap in hammerhead species relative to their carcharhinid sister taxa and is consistent with the ‘enhanced binocular
field’ hypothesis.

- by Mikki McComb-Kobza
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- Elasmobranchs, Sensory Biology, Hammerhead Sharks

In this article the problem of perception is highlighted from a philosophical, physiological and psychological point of view. The essay (second update) is followed by a list of publications, journals and websites about perception. The... more

- by Hans Kuijper
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- Computer Vision, Perception, Phonology, Sensory Ecology

Multiple sensory modalities and a complex array of escape behaviors have evolved as components of anti-predator responses in squids. The goals of this study include: examine the role of the lateral line analogue and vision in successful predator evasion; (2) measure kinematics of escape jetting; (3) document how chromatic patterning, posturing and inking in squid change in response to predators; and (4) investigate escape jet hydrodynamics of squid. Given that squids undergo considerable morphological, ecological, and behavioral changes throughout ontogeny, the goals above were all investigated across different life history stages. To test the respective roles of vision and the lateral line analogue, squid of different life stages were recorded in the presence of natural predators under light and dark conditions with their lateral line analogue intact and ablated via a pharmacological technique. Anti-predator behaviors of squid throughout ontogeny were studied in a series of predator-prey trials using high-speed videography. Additionally, the hydrodynamics and kinematics of high velocity escape jets in squid were examined using a combination of 2D/3D velocimetry. The lateral line analogue played a role in initiation of an escape response at the earliest life stages, and continued to v ACKNOWLEDGMENTS I owe a debt of gratitude to my advisor Dr. Ian Bartol for his patience and guidance through this program. It has truly been a pleasure to be a part of his lab family for the past five years. I am also very thankful for the input of all my committee members: Dr. Lisa Horth, Dr.

- by Carly Anne York
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- Cephalopods, Sensory Biology

Visual temporal resolution and scotopic spectral sensitivity of
three coastal shark species (bonnethead Sphyrna tiburo, scalloped
hammerhead Sphyrna lewini, and blacknose shark Carcharhinus
acronotus) were investigated by electroretinogram.
Temporal resolution was quantified under photopic and scotopic
conditions using response waveform dynamics and maximum
critical flicker-fusion frequency (CFF). Photopic CFFmax
was significantly higher than scotopic CFFmax in all species. The
bonnethead had the shortest photoreceptor response latency
time (23.5 ms) and the highest CFFmax (31 Hz), suggesting that
its eyes are adapted for a bright photic environment. In contrast,
the blacknose had the longest response latency time (34.8 ms)
and lowest CFFmax (16 Hz), indicating its eyes are adapted for
a dimmer environment or nocturnal lifestyle. Scotopic spectral
sensitivity revealed maximum peaks (480 nm) in the bonnethead
and blacknose sharks that correlated with environmental
spectra measured during twilight, which is a biologically relevant
period of heightened predation.

- by Mikki McComb-Kobza
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- Vision Science, Elasmobranchs, Sensory Biology

Visual temporal resolution and scotopic spectral sensitivity of three coastal shark species (bonnethead Sphyrna tiburo, scalloped hammerhead Sphyrna lewini, and blacknose shark Carcharhinus acronotus) were investigated by electroretinogram. Temporal resolution was quantified under photopic and scotopic conditions using response waveform dynamics and maximum critical flicker-fusion frequency (CFF). Photopic CFF max was significantly higher than scotopic CFF max in all species. The bonnethead had the shortest photoreceptor response latency time (23.5 ms) and the highest CFF max (31 Hz), suggesting that its eyes are adapted for a bright photic environment. In contrast, the blacknose had the longest response latency time (34.8 ms) and lowest CFF max (16 Hz), indicating its eyes are adapted for a dimmer environment or nocturnal lifestyle. Scotopic spectral sensitivity revealed maximum peaks (480 nm) in the bonnethead and blacknose sharks that correlated with environmental spectra measured during twilight, which is a biologically relevant period of heightened predation.

- by Mikki McComb-Kobza
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- Physiology, Vision Science, Visual perception, Biology

Mechanoreceptive and electroreceptive anatomical specialisations in freshwater elasmobranch fishes are largely unknown. The freshwater whipray, Himantura dalyensis, is one of a few Australian elasmobranch species that occur in low salinity (oligohaline) environments. The distribution and morphology of the mechanoreceptive lateral line and the electroreceptive ampullae of Lorenzini were investigated by dissection and compared with previous studies on related species. The distribution of the pit organs resembles that of a marine ray, Dasyatis sabina, although their orientation differs. The lateral line canals of H. dalyensis are distributed similarly compared with two marine relatives, H. gerrardi and D. sabina. However, convolutions of the ventral canals and proliferations of the infraorbital canal are more extensive in H. dalyensis than H. gerrardi. The intricate nature of the ventral, non-pored canals suggests a mechanotactile function, as previously demonstrated in D. sabina. The ampullary system of H. dalyensis is not typical of an obligate freshwater elasmobranch (i.e. H. signifer), and its morphology and pore distribution resembles those of marine dasyatids. These results suggest that H. dalyensis is euryhaline, with sensory systems adapted similarly to those described in marine and estuarine species.

- by Barbara E Wueringer
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- Genetics, Marine Biology, Physiology, Oceanography
- by Matthew Lim
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- Sensory Biology

- by Teag Marzaray
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- Marine Biology, Ecology, Sharks, Elasmobranchs

Eye reduction occurs in many troglobitic, fossorial, and deep-sea animals but there is no clear consensus on its evolutionary mechanism. Given the highly conserved and pleiotropic nature of many genes instrumental to eye development, degeneration might be expected to follow consistent evolutionary trajectories in closely related animals. We tested this in a comparative study of ocular anatomy in solariellid snails from deep and shallow marine habitats using morphological, histological, and tomographic techniques, contextualized phylogenetically. Of 67 species studied, 15 lack retinal pigmentation and at least seven have eyes enveloped by surrounding epithelium. Independent instances of reduction follow numerous different morphological trajectories. We estimate eye loss has evolved at least seven times within Solariellidae, in at least three different ways: characters such as pigmentation loss, obstruction of eye aperture, and " lens " degeneration can occur in any order. In one instance, two morphologically distinct reduction pathways appear within a single genus, Bathymophila. Even amongst closely related animals living at similar depths and presumably with similar selective pressures, the processes leading to eye loss have more evolutionary plasticity than previously realized. Although there is selective pressure driving eye reduction, it is clearly not morphologically or developmentally constrained as has been suggested by previous studies. K E Y W O R D S : Deep sea, eye degeneration, eye loss, eye evolution, Solariellidae, vision, Vetigastropoda.

- by Lauren Sumner-Rooney
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- Evolutionary Biology, Sensory Ecology, Neuroanatomy, Deep sea ecology

SUMMARYSeveral factors that influence the evolution of the unusual head morphology of hammerhead sharks (family Sphyrnidae) are proposed but few are empirically tested. In this study we tested the ‘enhanced binocular field’ hypothesis (that proposes enhanced frontal binocularity) by comparison of the visual fields of three hammerhead species: the bonnethead shark, Sphyrna tiburo, the scalloped hammerhead shark, Sphyrna lewini, and the winghead shark, Eusphyra blochii, with that of two carcharhinid species: the lemon shark, Negaprion brevirostris, and the blacknose shark, Carcharhinus acronotus. Additionally, eye rotation and head yaw were quantified to determine if species compensate for large blind areas anterior to the head. The winghead shark possessed the largest anterior binocular overlap (48 deg.) and was nearly four times larger than that of the lemon (10 deg.) and blacknose (11 deg.) sharks. The binocular overlap in the scalloped hammerhead sharks (34 deg.) was greater than ...

- by Mikki McComb-Kobza
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- Biology, Medicine, Biological Sciences, Sharks

Several factors that influence the evolution of the unusual head morphology of hammerhead sharks (family Sphyrnidae) are proposed but few are empirically tested. In this study we tested the 'enhanced binocular field' hypothesis (that proposes enhanced frontal binocularity) by comparison of the visual fields of three hammerhead species: the bonnethead shark, Sphyrna tiburo, the scalloped hammerhead shark, Sphyrna lewini, and the winghead shark, Eusphyra blochii, with that of two carcharhinid species: the lemon shark, Negaprion brevirostris, and the blacknose shark, Carcharhinus acronotus. Additionally, eye rotation and head yaw were quantified to determine if species compensate for large blind areas anterior to the head. The winghead shark possessed the largest anterior binocular overlap (48deg.) and was nearly four times larger than that of the lemon (10deg.) and blacknose (11deg.) sharks. The binocular overlap in the scalloped hammerhead sharks (34deg.) was greater than the bonnethead sharks (13deg.) and carcharhinid species; however, the bonnethead shark did not differ from the carcharhinids. These results indicate that binocular overlap has increased with lateral head expansion in hammerhead sharks. The hammerhead species did not demonstrate greater eye rotation in the anterior or posterior direction. However, both the scalloped hammerhead and bonnethead sharks exhibited greater head yaw during swimming (16.9deg. and 15.6deg., respectively) than the lemon (15.1deg.) and blacknose (15.0deg.) sharks, indicating a behavioral compensation for the anterior blind area. This study illustrates the larger binocular overlap in hammerhead species relative to their carcharhinid sister taxa and is consistent with the 'enhanced binocular field' hypothesis.

- by Stephen Kajiura
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- Biological Sciences, Sharks, Movement, Elasmobranchs

Blind Mexican cave fish (Astyanax fasciatus Cuvier 1819) were purchased from a commercial aquarium supplier. Adult blind cave fish, ranging in size from 40 to 60 mm in total length, with a mean length of 44±4 mm, were housed in glass aquaria (250 l and 75 l) and maintained at a constant temperature of 25°C. Water in the aquaria was standardised by adding CaCl 2 and synthetic sea salt (Instant Ocean, Aquarium Systems, OH, USA) to deionised water in order to maintain a Ca 2+ concentration of slightly above 1.0 mmol l-1 , at a conductance of approximately 750 μS. The Ca 2+

- by John Montgomery
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- Animal Behavior, Biomechanics, Behavior, Fish Biology

Blind cavefish use a form of active sensing in which burst-coast swimming motions generate flow signals detected by the lateral line. To determine if blind cavefish have evolved behavioral specializations for active flowsensing, including the ability to regulate flow signal production through lateral line feedback, the swimming kinematics of blind and sighted morphs of Astyanax were compared before and after 24 h of familiarization with a novel, dark environment and with and without lateral line functionality. Although both morphs showed little difference in the vast majority of kinematic parameters measured, blind morphs differed significantly from sighted morphs in having a much higher incidence of swim cycle sequences devoid of sharp turns. Both lateral line deprivation and familiarization with the arena led to significant declines in this number for blind, but not sighted morphs. These findings suggest that swimming kinematics are largely conserved, but that blind morphs have nevertheless evolved enhanced abilities to use lateral line feedback when linking swim cycles into continuous, straight trajectories for exploratory purposes. This behavioral specialization can best be understood in terms of the intermittent and short-range limitations of active flow-sensing and the challenges they pose for spatial orientation and navigation.

- by Delfinn Tan and +1
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- Fish Biology, Animal Behaviour, Sensory Biology, Aquatic Biology
- by Hong Young Yan
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- Sensory Biology