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Nicholas C. Wegner - One of the best experts on this subject based on the ideXlab platform.
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Elasmobranch Gill Structure
Fish Physiology, 2015Co-Authors: Nicholas C. WegnerAbstract:1. Introduction 2. Overview of the Elasmobranch Gill 3. Evolution of the Gill: Elasmobranch Gill Structure in Relation to Other Fishes 4. Elasmobranch Versus Teleost Ventilation 5. Details of the Elasmobranch Gill 5.1. Gross Morphology – Unique Features 5.2. Gill Vasculature 5.3. The Gill Epithelium 6. Diversity in Elasmobranch Gill Dimensions and Morphology 6.1. Gill Arches 6.2. Gill Morphometrics 6.3. Theory on Elasmobranch Gill Dimensions and Limits to Gill Diffusion Capacity 6.4. Scaling 6.5. Adaptations for Fast Swimming 6.6. Adaptations for Hypoxia 6.7. Adaptations for Freshwater 6.8. Adaptations for Feeding – Gill Rakers 7. Conclusions As in other fishes, the Gills of elasmobranchs are a critical interface between the internal and external environments and play vital roles in gas exchange, ion and pH balance, and the excretion of nitrogenous waste. Although the functional unit of the fish Gill (the Gill filament) has remained structurally and functionally intact throughout the course of fish evolution and diversification from lampreys to teleosts, the elasmobranch Gill has a number of largely unique features. Perhaps most notably is the connection of the Gill filaments to interbranchial septa, which affects not only the flow of water through the Gills, but may provide a number of specific advantages and disadvantages to elasmobranch respiration. This chapter discusses both the structural similarities and differences of the elasmobranch Gill in comparison to other fish groups and describes the breadth of structural branchial diversity within elasmobranchs, ranging from deep-water sharks and rays with six or seven pairs of Gill arches to surface-oriented giants that use specialized Gill rakers to sieve micro-sized prey out of the water.
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Reexamination of the Byczkowska-Smyk Gill surface area data for European teleosts, with new measurements on the pikeperch, Sander lucioperca
Reviews in Fish Biology and Fisheries, 2012Co-Authors: Leszek Satora, Nicholas C. WegnerAbstract:This paper reexamines the Gill morphometrics of 20 European teleosts first reported in the early Gill literature by Byczkowska-Smyk and colleagues in attempt to clarify the long-recognized discrepancies between these data and those obtained in subsequent works. Determination of Gill dimensions for the pikeperch, Sander lucioperca, in this study (a species for which Byczkowska-Smyk reported data), along with a literature review for other European teleosts, reveals inaccurate estimation of the total Gill surface area by up to 18× for 19 of the 20 species reexamined. This error results primarily from imprecise determination of the bilateral surface area of individual Gill lamellae and, to a lesser extent, the incorrect assumption that lamellar area and frequency are species-specific constants that do not vary with fish body mass. This review compiles Gill morphometric data from various sources to be used in place of the inaccurate Gill area estimates of Byczkowska-Smyk and colleagues and thereby clears the way for higher resolution in the comparative analysis of Gill morphology and its correlation to fish habitat and life history characteristics.
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Reexamination of the Byczkowska-Smyk Gill surface area data for European teleosts, with new measurements on the pikeperch, Sander lucioperca
Reviews in Fish Biology and Fisheries, 2012Co-Authors: Leszek Satora, Nicholas C. WegnerAbstract:This paper reexamines the Gill morphometrics of 20 European teleosts first reported in the early Gill literature by Byczkowska-Smyk and colleagues in attempt to clarify the long-recognized discrepancies between these data and those obtained in subsequent works. Determination of Gill dimensions for the pikeperch, Sander lucioperca, in this study (a species for which Byczkowska-Smyk reported data), along with a literature review for other European teleosts, reveals inaccurate estimation of the total Gill surface area by up to 18× for 19 of the 20 species reexamined. This error results primarily from imprecise determination of the bilateral surface area of individual Gill lamellae and, to a lesser extent, the incorrect assumption that lamellar area and frequency are species-specific constants that do not vary with fish body mass. This review compiles Gill morphometric data from various sources to be used in place of the inaccurate Gill area estimates of Byczkowska-Smyk and colleagues and thereby clears the way for higher resolution in the comparative analysis of Gill morphology and its correlation to fish habitat and life history characteristics.
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oxygen utilization and the branchial pressure gradient during ram ventilation of the shortfin mako isurus oxyrinchus is lamnid shark tuna convergence constrained by elasmobranch Gill morphology
The Journal of Experimental Biology, 2012Co-Authors: Nicholas C. Wegner, Chin N Lai, Kristina B Bull, Jeffrey B GrahamAbstract:Ram ventilation and Gill function in a lamnid shark, the shortfin mako, Isurus oxyrinchus , were studied to assess how Gill structure may affect the lamnid–tuna convergence for high-performance swimming. Despite differences in mako and tuna Gill morphology, mouth gape and basal swimming speeds, measurements of mako O2 utilization at the Gills (53.4±4.2%) and the pressure gradient driving branchial flow (96.8±26.1 Pa at a mean swimming speed of 38.8±5.8 cm s–1) are similar to values reported for tunas. Also comparable to tunas are estimates of the velocity (0.22±0.03 cm s–1) and residence time (0.79±0.14 s) of water though the interlamellar channels of the mako Gill. However, mako and tuna Gills differ in the sites of primary branchial resistance. In the mako, approximately 80% of the total branchial resistance resides in the septal channels, structures inherent to the elasmobranch Gill that are not present in tunas. The added resistance at this location is compensated by a correspondingly lower resistance at the Gill lamellae accomplished through wider interlamellar channels. Although greater interlamellar spacing minimizes branchial resistance, it also limits lamellar number and results in a lower total Gill surface area for the mako relative to tunas. The morphology of the elasmobranch Gill thus appears to constrain Gill area and, consequently, limit mako aerobic performance to less than that of tunas.
Leszek Satora - One of the best experts on this subject based on the ideXlab platform.
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Reexamination of the Byczkowska-Smyk Gill surface area data for European teleosts, with new measurements on the pikeperch, Sander lucioperca
Reviews in Fish Biology and Fisheries, 2012Co-Authors: Leszek Satora, Nicholas C. WegnerAbstract:This paper reexamines the Gill morphometrics of 20 European teleosts first reported in the early Gill literature by Byczkowska-Smyk and colleagues in attempt to clarify the long-recognized discrepancies between these data and those obtained in subsequent works. Determination of Gill dimensions for the pikeperch, Sander lucioperca, in this study (a species for which Byczkowska-Smyk reported data), along with a literature review for other European teleosts, reveals inaccurate estimation of the total Gill surface area by up to 18× for 19 of the 20 species reexamined. This error results primarily from imprecise determination of the bilateral surface area of individual Gill lamellae and, to a lesser extent, the incorrect assumption that lamellar area and frequency are species-specific constants that do not vary with fish body mass. This review compiles Gill morphometric data from various sources to be used in place of the inaccurate Gill area estimates of Byczkowska-Smyk and colleagues and thereby clears the way for higher resolution in the comparative analysis of Gill morphology and its correlation to fish habitat and life history characteristics.
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Reexamination of the Byczkowska-Smyk Gill surface area data for European teleosts, with new measurements on the pikeperch, Sander lucioperca
Reviews in Fish Biology and Fisheries, 2012Co-Authors: Leszek Satora, Nicholas C. WegnerAbstract:This paper reexamines the Gill morphometrics of 20 European teleosts first reported in the early Gill literature by Byczkowska-Smyk and colleagues in attempt to clarify the long-recognized discrepancies between these data and those obtained in subsequent works. Determination of Gill dimensions for the pikeperch, Sander lucioperca, in this study (a species for which Byczkowska-Smyk reported data), along with a literature review for other European teleosts, reveals inaccurate estimation of the total Gill surface area by up to 18× for 19 of the 20 species reexamined. This error results primarily from imprecise determination of the bilateral surface area of individual Gill lamellae and, to a lesser extent, the incorrect assumption that lamellar area and frequency are species-specific constants that do not vary with fish body mass. This review compiles Gill morphometric data from various sources to be used in place of the inaccurate Gill area estimates of Byczkowska-Smyk and colleagues and thereby clears the way for higher resolution in the comparative analysis of Gill morphology and its correlation to fish habitat and life history characteristics.
Hannes Pohla - One of the best experts on this subject based on the ideXlab platform.
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Gill surface area of water-breathing freshwater fish
Reviews in Fish Biology and Fisheries, 1992Co-Authors: Margit Palzenberger, Hannes PohlaAbstract:To provide a hitherto lacking review which focuses on Gill surface area of freshwater fish, we collected and analysed morphometric data from the literature. The scaling exponent of Gill area ranges from 0.36 to 1.13, with a mean value of 0.76. The absolute values for the largest Gill areas are about 5 times as high as those of the smallest. This range resembles that of marine fish, if specially adapted steady swimmers, such as tunnies and some sharks, are excluded. Generally it appears that the Gill areas of freshwater fish are smaller than those of comparable marine species. To establish whether a relationship exists between Gill area and swimming activity or oxygen content of water, the activity of each species and the oxygen content of its habitat were estimated and checked against the Gill area. ANOVA revealed that activity explains the presence of the smallest Gill areas only, while oxygen content does not correlate with Gill area at all. The morphometric variables determining Gill area (total length of filaments, average lamellar density, average lamellar area) are highly correlated; total Gill area correlates mainly with lamellar density and to a lesser degree with filament length; lamellar area varies independently. Different populations of the same species exhibit striking differences with respect to Gill areas, total length of filaments, average lamellar density and average lamellar area. These differences point to a substantial morphological plasticity of the Gill system.
Kathleen M. Scott - One of the best experts on this subject based on the ideXlab platform.
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Allometry of Gill weights, Gill surface areas, and foot biomass δ13C values of the chemoautotroph–bivalve symbiosis Solemya velum
Marine Biology, 2005Co-Authors: Kathleen M. ScottAbstract:The protobranch bivalve Solemya velum Say, 1822 has large Gills, which harbor chemolithoautotrophic bacteria that supply the majority of the clam’s organic carbon. A substantial portion of the CO2, O2, H2S, and other nutrients necessary for symbiont autotrophy and host heterotrophy are acquired from the environment through the Gills, whose large size may be necessary to facilitate the acquisition of sufficient O2 from S. velum’s habitat to meet the combined demands of the host and symbionts. Large Gills may also result in an oversupply of CO2, which may in turn be responsible for the isotopically depleted δ13C values observed in S. velum biomass (−31 to −34‰). Alternatively, Gill hypertrophy may simply be an adaptation to house a large population of symbionts adjacent to their environmental source of dissolved gases and other nutrients. To better understand Gill function in this symbiosis, Gill weights, Gill surface areas, and foot δ13C values were measured as a function of total weights. S. velum Gill weights were found to be a substantial portion of total clam weight, averaging 38% of wet weight, compared to nonsymbiotic protobranch bivalves Yoldia limatula Say, 1831 (5%) and Nucula proxima Say, 1822 (11%). Gill weights are a smaller percentage of total weight in larger individuals; the allometric equation for Gill weight (G) as a function of total weight (M) is G=0.26M0.85. Dry weights scale similarly. Gill surface areas are immense; the average Gill surface area measured was 107 cm2 g−1 total soft tissue wet weight, the highest value for any marine invertebrate. Gill surface area (SA) also scales with size (SA=69.8M0.85). When Gill surface areas were calculated with respect to Gill wet weights, they did not scale with size. The δ13C values do not scale with size either, consistent with high rates of CO2 supply at all sizes. Extraordinarily high rates of CO2 supply relative to demand are supported by a model for CO2 delivery based on Fick’s law and the allometric relationship between surface areas and total weight, consistent with a role for large Gill surface areas in the generation of isotopically depleted tissue δ13C values.
Margit Palzenberger - One of the best experts on this subject based on the ideXlab platform.
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Gill surface area of water-breathing freshwater fish
Reviews in Fish Biology and Fisheries, 1992Co-Authors: Margit Palzenberger, Hannes PohlaAbstract:To provide a hitherto lacking review which focuses on Gill surface area of freshwater fish, we collected and analysed morphometric data from the literature. The scaling exponent of Gill area ranges from 0.36 to 1.13, with a mean value of 0.76. The absolute values for the largest Gill areas are about 5 times as high as those of the smallest. This range resembles that of marine fish, if specially adapted steady swimmers, such as tunnies and some sharks, are excluded. Generally it appears that the Gill areas of freshwater fish are smaller than those of comparable marine species. To establish whether a relationship exists between Gill area and swimming activity or oxygen content of water, the activity of each species and the oxygen content of its habitat were estimated and checked against the Gill area. ANOVA revealed that activity explains the presence of the smallest Gill areas only, while oxygen content does not correlate with Gill area at all. The morphometric variables determining Gill area (total length of filaments, average lamellar density, average lamellar area) are highly correlated; total Gill area correlates mainly with lamellar density and to a lesser degree with filament length; lamellar area varies independently. Different populations of the same species exhibit striking differences with respect to Gill areas, total length of filaments, average lamellar density and average lamellar area. These differences point to a substantial morphological plasticity of the Gill system.
