Gill Dimensions Research Articles

Interspecific Differences in the Metabolic Rate, Gill Dimension and Hematology of Fish in an Amazonian Floodplain Lake

It has been hypothesized that respiratory physiology in fish is closely associated with ecological traits. Therefore, data on gill morphometrics (lamellae frequency, gill surface area and barrier thickness), metabolic rate (oxygen consumption) and blood oxygen capacity (hematology) were analyzed in several fish, including benthic, bentho-pelagic and pelagic species collected in an Amazon floodplain lake. Similar to other teleostean species, the 2nd and 3rd gill arches have numerous large filaments in both pelagic and benthic species, as these characteristics tend to increase the gill surface area. A large gill area (4 to 7 cm2 g-1, mass-specific) is associated with a high (100 to 300 mg O2 h-1 kg-1) routine oxygen consumption rate and has been observed in active pelagic swimmers, such as Cichla monoculus and Pygocentrus nattereri. Benthic dwelling fish (e.g., Pterygoplichthys pardalis and Sorubim lima) have low metabolic rates (20 to 50 mg O2 h-1 kg-1), small gill dimensions (2 to 3 cm2 g-1, mass-specific), low hemoglobin levels (3 to 5 g dL-1), reduced numbers of circulating red blood cells (1 to 2 Í106 mm-3) and low hematocrit values (25 to 35%) compared to pelagic species. These results demonstrated that pelagic fish have high routine oxygen consumption rates compatible with their large gill surface area and high blood oxygen capacity, whereas benthic species have low metabolic rates, small gill dimensions and reduced blood oxygen capacity.

Lanthanum exerts acute toxicity and histopathological changes in gill and liver tissue of rare minnow (Gobiocypris rarus).

We evaluated the acute toxicity effects of lanthanum (La(III)) on gill and liver of rare minnow (Gobiocypris rarus). The median lethal concentration of La (III) at 96 h was 1.92 mg L-1. Rare minnow were reared in freshwater and exposed to 0.04, 0.08, 0.16, 0.32 and 0.80 mg L-1 La (III) for 21 d. Gill and liver samples were analyzed by light microscopy. The main histopathological changes induced by La (III) in gills were epithelial lifting, filamentary epithelial proliferation,edema, lamellar fusion, desquamation, and necrosis. Histopathological changes induced by La (III) in the liver included dilation of sinusoids, focal congestion, pyknotic nuclei, karyohexis and karyolysis, vacuolar degeneration, and numerous necrosis areas. Hypsometric analysis indicated significant changes in the measures of gill dimensions (average length, width, area), suggesting metabolic disturbance (gas exchange) upon La (III) exposure. The result showed that La (III) severely affects fish gill and liver.

Is the scaling of swim speed in sharks driven by metabolism?

The movement rates of sharks are intrinsically linked to foraging ecology, predator-prey dynamics and wider ecosystem functioning in marine systems. During ram ventilation, however, shark movement rates are linked not only to ecological parameters, but also to physiology, as minimum speeds are required to provide sufficient water flow across the gills to maintain metabolism. We develop a geometric model predicting a positive scaling relationship between swim speeds in relation to body size and ultimately shark metabolism, taking into account estimates for the scaling of gill dimensions. Empirical data from 64 studies (26 species) were compiled to test our model while controlling for the influence of phylogenetic similarity between related species. Our model predictions were found to closely resemble the observed relationships from tracked sharks, providing a means to infer mobility in particularly intractable species.

Gill dimensions in near-term embryos of Amazonian freshwater stingrays (Elasmobranchii: Potamotrygonidae) and their relationship to the lifestyle and habitat of neonatal pups

This comparative study of gill morphometrics in near-term embryos of freshwater stingray potamotrygonids examines gill dimensions in relation to neonatal lifestyle and habitat. In embryos of the potamotrygonids Paratrygon aiereba, Plesiotrygon iwamae, Potamotrygon motoro, Potamotrygon orbignyi, and cururu ray Potamotrygon sp. the number and length of filaments, total gill surface area, mass-specific surface area, water-blood diffusion distance, and anatomical diffusion factor were analysed. In all potamotrygonids, the 3rd branchial arch possessed a larger respiratory surface than the other gill arches. Larger embryos had more gill surface area and large spiracles, which are necessary to maintain the high oxygen uptake needed due to their larger body size. However, the higher mass-specific gill surface area observed in near-term embryos may be advantageous because neonates can use hypoxic environments as refuges against predators, as well as catch small prey that inhabit the same environment. As expected from their benthic mode of life, freshwater stingrays are sluggish animals compared to pelagic fishes. However, based on gill respiratory morphometry (such as gill area, mass-specific gill area, the water-blood diffusion barrier, anatomical diffusion factor, and relative opening of the spiracle), subtypes of lifestyles can be observed corresponding to: active, intermediate, and sluggish species according to Gray's scale.

Gill morphometrics of the thresher sharks (Genus Alopias): Correlation of gill dimensions with aerobic demand and environmental oxygen.

Gill morphometrics of the three thresher shark species (genus Alopias) were determined to examine how metabolism and habitat correlate with respiratory specialization for increased gas exchange. Thresher sharks have large gill surface areas, short water-blood barrier distances, and thin lamellae. Their large gill areas are derived from long total filament lengths and large lamellae, a morphometric configuration documented for other active elasmobranchs (i.e., lamnid sharks, Lamnidae) that augments respiratory surface area while limiting increases in branchial resistance to ventilatory flow. The bigeye thresher, Alopias superciliosus, which can experience prolonged exposure to hypoxia during diel vertical migrations, has the largest gill surface area documented for any elasmobranch species studied to date. The pelagic thresher shark, A. pelagicus, a warm-water epi-pelagic species, has a gill surface area comparable to that of the common thresher shark, A. vulpinus, despite the latter's expected higher aerobic requirements associated with regional endothermy. In addition, A. vulpinus has a significantly longer water-blood barrier distance than A. pelagicus and A. superciliosus, which likely reflects its cold, well-oxygenated habitat relative to the two other Alopias species. In fast-swimming fishes (such as A. vulpinus and A. pelagicus) cranial streamlining may impose morphological constraints on gill size. However, such constraints may be relaxed in hypoxia-dwelling species (such as A. superciliosus) that are likely less dependent on streamlining and can therefore accommodate larger branchial chambers and gills.

A New Genus and Species of Small Minnow Mayflies (Ephemeroptera: Baetidae) from Far Northern North America

A newly discovered larva of Baetidae (Insecta, Ephemeroptera) is described from Nunavut, Canada as Kirmaushenkreena zarankoae, n. gen. and n. sp. The new taxon has a unique combination of generic characteristics, including unusual claw armature that is diagnostic. Closest relatives of the new genus may possibly be in the Indobaetis complex of genera. The absence of a villopore sets the new species apart from other far northern North American baetine species, and other differences and convergent similarities such as claw setation and gill dimensions among that fauna are discussed.

Reexamination of the Byczkowska-Smyk gill surface area data for European teleosts, with new measurements on the pikeperch, Sander lucioperca

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.

Comparative study of gill neuroepithelial cells and their innervation in teleosts and Xenopus tadpoles

Peripheral O(2) chemoreceptors initiate adaptive cardiorespiratory responses to hypoxia in vertebrates. Morphological and physiological evidence suggests that, in fish, neuroepithelial cells (NECs) of the gill perform this role. We conducted a comparative examination in three species of teleosts (zebrafish, goldfish and trout) and larvae of the amphibian Xenopus laevis, using whole-mount gill preparations and confocal immunofluorescence, to elucidate the distribution, morphology and innervation of gill NECs. Nerve fibres were immunolabelled with the neuronal marker zn-12 and were associated with serotonin-immunoreactive NECs in the gills of all species tested. With the exception of trout, innervated NECs were present on all gill arches in the filaments and respiratory lamellae in fish and on homologous structures in Xenopus (i.e. gill "tufts", including respiratory terminal branches). Thus, the distribution and innervation of NECs of the internal gills of amphibians and teleosts are relatively well conserved, suggesting an important role for gill NECs as O(2) chemoreceptors in aquatic vertebrates. Furthermore, the size and density of gill NECs is variable among teleosts and developmental stages of Xenopus larvae and may be dependent on general gill dimensions or environmental conditions. This report constitutes the first comparative study of gill NECs in fish and amphibians and highlights the significance of gill NECs as an evolutionary model for studying O(2) sensing in vertebrates.

Gill and liver histopathological changes in yellow perch ( Perca flavescens) and goldfish ( Carassius auratus) exposed to oil sands process-affected water

The extraction of bitumen from the Athabasca oil sands (Alberta, Canada) produces significant volumes of process-affected water containing elevated levels of naphthenic acids (NAs), ions, and polycyclic aromatic hydrocarbons (PAHs). The sublethal response of aquatic organisms exposed to oil sands constituents in experimental aquatic environments that represent possible reclamation options has been studied. In this study, the effects of process-affected waters on gill and liver tissues in yellow perch ( Perca flavescens) and caged goldfish ( Carassius auratus) held in several reclamation ponds at Syncrude's Mildred Lake site have been assessed. Following a 3-week exposure, significant gill (epithelial cell necrosis, mucous cell proliferation) and liver (hepatocellular degeneration, inflammatory cell infiltration) histopathological changes were noted in fish held in waters containing high levels of oil sands process-affected water. In addition, measurements of gill dimensions (gill morphometrical indices) proved sensitive and provided evidence of a physiological disturbance (gas exchange) with exposure to oil sands materials. Due to the complexity of oil sands process-affected water, the cause of the alterations could not be attributed to specific oil sands constituents. However, the histopathological parameters were strong indicators of exposure to oil sands process-affected water and morphometrical data were sensitive indicators of pathological response, which can be used to identify the interactive effects of ionic content, NAs, and PAHs in future laboratory studies.

Muscular alteration of gill geometry in vitro: implications for bivalve pumping processes.

In bivalves, water-pumping potential is determined both by ciliary activity and by the geometry of the system of passageways that acts as a conduit for water flow. Smooth muscles intrinsic to the gills of eulamellibranch bivalves possess the anatomical organization needed to regulate the dimensions of these water passageways. The tone of these muscles can be controlled experimentally using excitatory neurotransmitters to elicit muscle contraction and by removing Ca++ from the Ringer's solution to induce muscular relaxation. These experimental methods were used to investigate the effects of smooth muscle tone on the gill dimensions of two freshwater bivalves, Dreissena polymorpha and Corbicula fluminea, and one marine bivalve, Mercenaria mercenaria. In addition, endoscopic observations were made from the suprabranchial chamber of a freshwater unionid, Lampsilis anodontoides. Contraction of gill muscles led to a significant reduction in interfilament width, internal ostial area, and the cross-sectional area of the water tubes. Endoscopic observation from minimally disturbed L. anodontoides revealed rapid constriction of the water tubes upon contraction of the muscles of the gill and gill axis. Taken together, these data support the idea that alteration of smooth muscle tone in the gill provides a mechanism for controlling water-pumping activities.

Functional morphology of gills and respiratory area of two active rheophilic fish species, Plagioscion squamosissimus and Prochilodus scrofa

Measurements of gill dimensions were carried out on two ecologically distinct active rheophilic teleost species, the curvina Plagioscion squamosissimus and the curimbatáProchilodus scrofa, and were analysed in relation to body mass according to the equation Y=aWb. The gill respiratory areas of P. squamosissimus and P. scrofa were large as expected for active fish and increased with increasing body mass (b=0.70 and 0.72, respectively) showing no significant difference between them. However, the large respiratory area of both species was realized in a different way revealing an adaptation to the plasticity of head components related to feeding habits. Consequently, significant differences were found between the number and average length of gill filaments and the bilateral area of secondary lamellae. The respiratory area of P. scrofa was due mainly to larger bilateral surface area of the secondary lamellae and its growth coefficient (b=0.51) that was significantly higher (P<0.05) than that found for P. squamosissimus (b= 0.36). The frequency of secondary lamellae mm−1 of filament was similar in both species (22 ± 2 on one side of gill filament). The dimensions of gill components and the respiratory area of these species suggest a complex interaction between head form, and feeding habits related to the functional morphology of the gills to meet the oxygen requirements of each species.

Functional Organization of Intrinsic Gill Muscles in Zebra Mussels, Dreissena polymorpha (Mollusca: Bivalvia), and Response to Transmitters in Vitro

Functional Organization of Intrinsic Gill Muscles in Zebra Mussels, Dreissena polymorpha (Mollusca: Bivalvia), and Response to Transmitters in Vitro

Comparative study of gill dimensions of three erythrinid species in relation to their respiratory function

Gill dimensions were analysed in relation to body mass in three erythrinid fish, an air-breathing species, Hoplerythrinus unitaeniatus, and two ecologically distinct water-breathing species, Hoplias malabaricus and Hoplias lacerdae. Evidence was obtained of remarkable differences in patterns of increase in filament length, number of secondary lamellae, bilateral area of the secondary lamellae, total area of the secondary lamellae, and mass-specific area of the secondary lamellae among these three species. The analysis showed a large increase in respiratory surface area relative to body mass in H. malabaricus (b = 1.14) compared with Hoplias lacerdae (b = 0.81) and H. unitaeniatus (b = 0.66). This difference is mainly attributed to an increase surface area of individual secondary lamellae together with an increase in filament length and total number of secondary lamellae. The results indicate that the increased respiratory surface area of the H. malabaricus gill facilitates oxygen uptake in hypoxic environments as the fish grows and this suggests that gill dimensions may reflect ecological factors and not only respiratory requirements.

Effect of pulsatile flow on gas exchange in the fish gill: Theory and experimental data

A model for gas exchange in the fish gill allowing for time-varying water and blood flow is presented. An analysis based on this mathematical model shows that pulsatile water and blood flow potentially may reduce the efficiency of gas exchange significantly. The degree of inefficiency imposed on gas exchange is, however, determined by the physical dimensions of the gill and the gas capacitance coefficients of water and blood. Using anatomical and physiological data it is shown to be likely that for a large group of fishes, including the salmonids, pulsatility of water and blood flow affects gas exchange efficiency only marginally. A close coupling between cardiac and respiratory rhythms is therefore only of marginal advantage to gas exchange efficiency. Due to their exceptional gill dimensions tunas, and to a lesser extent mackerels, are susceptible to the negative effect of pulsatility on gas exchange, which may be one of the factors favouring ram ventilation in these species.

Gill dimensions, water pumping rate and body size in the mussel Mytilus edulis L.

Measurements of gill area, filament width and inter-filamental distance have been made from mussels in a range of sizes and from three sites. Water pumping rate of mussels has also been measured using a new technique which leaves the animal undisturbed and in otherwise still water. Both gill area and water pumping rate scale closely with (length) 2, gill area with (length) 2.06 and water pumping rate with (length) 2.19. Gill area and water pumping rate also scale closely with (weight) 0.67, and weight-specific gill area and pumping rate with (weight) −0.33. Utilising gill area and minimum water pumping data, the approach velocity of water to the gill surface is calculated as 0.23 mm s −1. The number of filaments mm −1, filament width and inter-filamental distance all vary with the size of the animal. Ostial area slightly increases with size but averages ≈37%. Resulting inter-filamental water velocity is 0.62 mm s −1, lower than most previous calculations but apparently compatible with the tip speed of the lateral cilia.

Gill morphometrics of two Antarctic fish species Pleuragramma antarcticum and Notothenia gibberifrons

Gill dimensions of 27 juvenile and adult Pleuragramma antarcticum from the southern Weddell Sea and of 28 juvenile and adult Notothenia gibberifrons from the South Orkney and South Shetland Islands were estimated. The unit gill area (UGA) of P. antarcticum ranged from 75 to 167 mm2/g (mean=105); gill area index (GAI) and water-blood distance (WBD) were found to be 1.38 cm2 and 3.3 μm, respectively. The exponent dg in the relationship total gill area to weight was found to be 0.90. It is concluded that P. antarcticum belongs to sluggish species and, although pelagic, its routine energy costs tend to be low. However, the closely packed lamellae (NL/mm=21) indicate more active behaviour in comparison with N. gibberifrons. A preliminary estimation of growth parameters (P, k) is presented. The sluggish behaviour of N. gibberifrons, as expected from its benthic mode of life, is reflected by the gill parameters: the very low UGA ranged from 39 to 118 mm2/g; GAI and dg were found to be 0.73 cm2 and 0.98, respectively. Comparing gill dimensions and general respiration characteristics of fish from antarctic, temperate and tropical waters it is concluded that antarctic fish have increased their scope for activity.

Pressure/flow relations in the interlamellar space of fish gills: theory and application in the rainbow trout

The nature of the water flow in the interlamellar spaces of fish gills is investigated using the basic fluid mechanical equations. The results show that the gill behaves like a low-pass filter, dampening the amplitude of the velocity oscillation when the frequency of the driving pressure differential exceeds some characteristic value and shifting the phase angle between the pressure and velocity pulses from 0 towards -π/2. The cut-off frequency is determined by the parameter v/r 2, where r is the half-width of the interlamellar space and v the kinematic viscosity. Using known gill dimensions the analysis shows that dampening of the velocity amplitude is not likely to occur at driving pressure frequencies below 100 Hz. Fourier analysis of the pressure differential recorded between buccal and opercular chambers of rainbow trout reveals that there is very little contribution from frequencies above 10 Hz, suggesting that interlamellar water flow is pulsatile and that the possibility for backflow exists.

Morphometrics of gills during growth and development of the air‐breathing habit in Colisa fasciatus (Bloch and Schneider)

Gill area and other component parameters of Colisa fasciatus during early life were measured for fish larvae divided into two groups (a) exclusively aquatic and (b) bimodal breathers. Statistical analyses of the data in relation to body size yielded two significantly different straight lines (one for aquatic and other for bimodal breathers) for each parameter. Morphological examinations of gill arches indicated that an increase in the gill area was brought about mainly by an increase in the filament length. The higher slope value (2.41) of gill area in the aquatic phase than that in the bimodal phase (b= 0.80) is suggestive of a higher weight‐specific metabolism in the younger larvae. A heterogenous growth pattern during early ontogenesis of the fish results in intraspecific variation in the gill dimensions which might have been influenced by the acquisition of the air‐breathing mechanism in the post‐larval stage, besides ecological factors.

Gill Morphometry of the Mudskipper,Boleophthalmus Boddarti

Measurements of gill dimensions in relation to body weight have been carried out in a mudskipper,Boleophthalmus boddarti. The data was analysed with respect to body weight using logarithmic transformations (logY= loga + blogW). The slope(b)of the log/log regression lines for the gill area, total filament length, average number of secondary lamellae/mm, bilateral area of an average secondary lamella, and total gill area/g were 1·0496, 0·427, -0·229, 0·851 and 00496 respectively.These results indicate variations in growth patterns for the different dimensions of the gills. The analysis shows that the increase in gill surface area with the body size is mainly due to an increase in the area of individual secondary lamellae and, to a lesser extent, an increase in filament length and total number of lamellae.The average weight-specific area for 14 specimens measured (3·6–35·4 g) was 108–15 mm2/g. This value is consistent with results obtained with some other intertidal species.Marked differences were found in the thickness of the water/blood barrier, which is thinner around the marginal channels. Morphometric diffusing capacity taking this heterogeneity into account was estimated as 0·0208 ml O2min1mmHg−1kg−1.INTRODUCTIONMorphological studies on the gills of many fish have shown adaptations of the basic structure which can be related to the particular mode of life. Among these adaptations, air-breathing species show many remarkable structural modifications (Munshi, 1976), which extend to the gills forming air sacs in species such asHeteropneustes fossilis(Hughes & Munshi, 1979). Fish which inhabit the intertidal zone, like other seashore animals, are subjected to periodic exposure to air, which may produce problems of water loss and reduction in support for the gills, with consequent collapse and restriction of gas exchange surfaces.

Allometry of gill dimensions in some British and American decapod crustacea

The gill areas and their component measurements of 16 species of North American crab and seven species of British decapod crustaceans have been analysed in relation to body mass using the method of logarithmic transformation.A wide range of relationships was found, each of which is typical for a given species. The slope, b, of the log/log regression lines varied from 0·5 to 1·0, the lower values being most commonly found in the Macrura. For the North American species the average slope is about 0·8 whereas for British brachyurans the relationship was close to linear (b=0·97).The analysis shows that the increase in gill surface body size is mainly due to the increasing area for individual platelets or gill lamellae.Comparison of weight‐specific gill areas for animals of the same body weight suggests that the most active species have larger gill areas. For some of these species the values (900mm2/g) approximate to those of active fish.As plots for interspecific relationships derived from average values for many individual species have slopes which are not typical for any of the component species, it is concluded that caution must be exercized when interpreting such interspecific plots in Allometric studies.