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THERMALLY INDUCED VARIATIONS IN VERTEBRAL NUMBER IN LUCANIA PARVA BAIRD (ANTHERINIFORMES: CYPRINODONTIDAE) REARED IN THE LABORATORY
Title
THERMALLY INDUCED VARIATIONS IN VERTEBRAL NUMBER IN LUCANIA PARVA BAIRD (ANTHERINIFORMES: CYPRINODONTIDAE) REARED IN THE LABORATORY.
Creator
MCCARTHY, LINDA J., Florida Atlantic University, Courtenay, Walter R. Jr., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description
Embryos of Lucania parva Baird from two sites in the Florida Keys were raised in four temperature regimes, 18°, 22°, 26°, and 30°C to determine the response of vertebral numbers to different incubation temperatures. The result was in inverse linear relationship, with vertebral numbers increasing with decreasing temperature. Temperature modified the developmental rates, causing the embryos in the warm temperatures to hatch earlier than those in the cold temperatures.
Date Issued
1978
PURL
http://purl.flvc.org/fcla/dt/13951
Subject Headings
Biology, Zoology
Format
Document (PDF)
Psychoacoustic evaluations of the West Indian manatee (Trichechus manatus latirostis)
Title
Psychoacoustic evaluations of the West Indian manatee (Trichechus manatus latirostis).
Creator
Gerstein, Edmund Roy, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
Abstract/Description
Psychoacoustic procedures were used to measure the heating thresholds of captive West Indian manatees under simultaneous masking conditions. Auditory detection thresholds of pulsed and non- pulsed pure tones, and complex sounds were measured against continuous white noise backgrounds through a series of forced-choice paradigms. Auditory thresholds as a function of signal intensity, center frequency, pulse repetition, spectral characteristics and bandwidth were measured. Resulting critical...
Show morePsychoacoustic procedures were used to measure the heating thresholds of captive West Indian manatees under simultaneous masking conditions. Auditory detection thresholds of pulsed and non- pulsed pure tones, and complex sounds were measured against continuous white noise backgrounds through a series of forced-choice paradigms. Auditory thresholds as a function of signal intensity, center frequency, pulse repetition, spectral characteristics and bandwidth were measured. Resulting critical signal-to-noise ratios for pure tone measurements suggest manatees have relatively acute frequency filtering abilities compared with humans and other marine mammals. Signal characteristics such as repetition rate along with amplitude and frequency modulation may lower detection thresholds by providing temporal contrasts against aperiodic background noise. Thresholds for frequency modulated bandlimited signals were measured near or below background noise levels. Threshold tests using broadband signals, including a species specific call and samples of boat noise suggest that loudness summation across critical bands, as well as modulation of signals, can reduce the effects of masking observed with pure tones. To test a manatee's ability to localize sound sources in relation to its position in the water, a forced-choice egocentric (orientation) paradigm was used. The manatee demonstrated equal localization of sounds originating from the left or right side. While accuracy improved with higher frequencies the manatee demonstrated good overall localization of both low and higher frequency sounds, suggesting it may utilize both time of arrival cues and intensity difference cues for localizing brief sounds. The psychoacoustic data reveal some hearing abilities unique to manatees, as well as hearing phenomena similar to those observed among mammals and other vertebrates species. Manatees are well adapted for hearing and locating high frequency sounds in noisy shallow water habitats where physical boundary and near surface phenomena such as the Lloyd Mirror Effect can impede the propagation of low frequencies. Narrow critical bands and selective perception of pulsed signals may be adaptations for detecting species-specific vocalizations. Results indicate manatees can not effectively detect the low frequency sounds of approaching boats from safe enough distances to avoid collisions in the wild.
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Date Issued
1999
PURL
http://purl.flvc.org/fcla/dt/12601
Subject Headings
Psychology, Psychobiology, Biology, Zoology, Agriculture, Fisheries and Aquaculture
Format
Document (PDF)
TO BUILD AN INVASIVE PREDATOR: INVESTIGATING THE MECHANICAL ROLE OF LIONFISH SPINES ON DEFENSE
Title
TO BUILD AN INVASIVE PREDATOR: INVESTIGATING THE MECHANICAL ROLE OF LIONFISH SPINES ON DEFENSE.
Creator
Galloway, Katherine Ann, Porter, Marianne E., Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description
The red lionfish, Pterois volitans, has arguably become the most successful marine invasive species to date. Yet, despite the invasion success of P. volitans, little is known about the morphology, physiology, and ecology of this species in their native and invaded habitats. The majority of recent studies have focused on the migration of P. volitans into new regions, digestion, and bacterial infections. Knowledge is lacking on the body plan of the invasive lionfish, specifically the numerous...
Show moreThe red lionfish, Pterois volitans, has arguably become the most successful marine invasive species to date. Yet, despite the invasion success of P. volitans, little is known about the morphology, physiology, and ecology of this species in their native and invaded habitats. The majority of recent studies have focused on the migration of P. volitans into new regions, digestion, and bacterial infections. Knowledge is lacking on the body plan of the invasive lionfish, specifically the numerous venomous spines that are protruding outward, making the body less streamlined. In this study we quantified the mechanical properties (bending and puncture) of the venomous spines of P. volitans, and related these properties to the cross-sectional morphology. We also documented variation in the cross-sectional morphology of spines from other lionfish species in their native regions. Lastly, we documented the dorsal spine joint morphology of the first three dorsal spines and the in situ range of motion as tissues were removed. We found that the long, numerous dorsal spines absorb more energy but are less stiff than the pelvic and anal spines. In addition, we found that the anal and pelvic spines are more effective at puncturing buccal skin from sharks and grouper. We found that the removal of connective tissue significantly changes lateral movement (abduction) for the first three dorsal spines. The removal of the fin sheath significantly alters forward movement (extension) for the first two dorsal spines. From morphology, mechanical property, and range of motion data for P. volitans, we propose that the numerous long dorsal spines are primarily used for intimidation, and are not as effective defense structures as the pelvic and anal spines. Having a substantial amount of intimidating, venomous spines may allow for the lionfish to conserve energy for other highly metabolically costly activities other than warding off predators, such as digestion and reproduction. Future studies could focus on the amount of venom in each spine, how long it takes for the venom to be made and replaced, how the venomous spines affect hydrodynamic flow, and in vivo range of motion during swimming and striking.
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Date Issued
2020
PURL
http://purl.flvc.org/fau/fd/FA00013512
Subject Headings
Red lionfish, Pterois volitans, Spines (Zoology), Mechanical properties of biological structures, Biomechanics
Format
Document (PDF)