Gill structure and morphometry of its respiratory components in the Baikalian golomyankas (Comephoridae; Cottoidei; Pisces)

All four pairs of gill arches in Comephorus baicalensis and C. dybowskii (Comephoridae) are well developed. In contrast to other Baikalian cottoids (Cottidae, Abyssocottidae), the slit behind the fourth arch is well preserved and two hemibranchs are present on this arch in the golomyankas. These anatomical details are considered to contradict the opinion that Comephoridae may be derived from other Baikalian Cottoidei. The arches in golomyankas are elongated and equipped with very strong spinous gill-rakers. The external sides of the upper and lower jaws are covered with numerous spinelike denticles, the apices of which are bent toward the mouth cavity. The denticles and the spinous gill-rakers are considered to be a specific adaptation in sluggish golomyankas for precise grasping of zooplankton of different sizes, as well as fish larvae. Respiratory components of the gill apparatus in the golomyankas are reduced considerably because of short gill filaments and the sparce distribution of small respiratory lamella on them. The allometry for the relationships between gill respiratory surface area (GRSA) and body mass (Y = aW^b) in both golomyankas is biphasic: in juvenile immature C. baicalensis Yj = 199.013 W^1.057 and in mature animals Ym = 322.354 W^0.731. In C. dybowskii the values for immature and mature animals are Yj = 95.736 W^1.190 and Ym = 199.609W^0.707, respectively. In the sluggish bathypelagic golomyankas (Comephorus) the GRSA per body weight unit is 5–6 times smaller than that found in more active secondarily pelagic Baikalian sculpins (Cottocomephorus) examined previously. © 1996 Wiley-Liss, Inc.     

Morphometry of gill respiratory area in the Baikalian deep-water sculpins Abyssocottus korotneffi and Cottinella boulengeri (Abyssocottidae,Cottoidei)

Abyssocottus korotneffi and Cottinella boulengeri are the deepest-living bottom species among freshwater teleosts. Both species have gill arches with nodulous gill-rakers equipped with sharp denticles. The gill-slit behind the fourth arch is reduced considerably and the hemibranch corresponding to this slit is absent, though some miniature structures resembling reduced filaments were occasionally observed there. The respiratory components of the gill apparatus in both species considered are much reduced, especially in A. korotneffi, because of the moderate number of relatively short gill filaments and the small number of respiratory lamella on them. The allometric relationship between the gill respiratory surface area (GRSA) and body mass (Y = aW^b) is expressed by Y = 328.55 W^0.724 for A. korotneffi (7–22 g) and by Y = 333.15 W^0.902 for C. boulengeri (3–24 g). In adult A. korotneffi, the GRSA index calculated per body weight unit is about 35% lower than that in C. boulengeri, but is 70% higher compared with the bathypelagic golomyanka Comephorus dybowskii previously examined. The data seem to correspond with the difference in biological activity of these species. J. Morphol. 233:105–112, 1997. © 1997 Wiley-Liss, Inc.     

Morphometry of the Gill Respiratory Area in Comephorus dybowskii and Some Other Endemic Cottoidei of Lake Baikal

Abstract Morphometric investigations of the gill apparatus in the small golomyanka, Comephorus dybowskii, revealed a unique structure and a very small gill respiratory area (GRSA) compared with other endemic Cottoidei of Lake Baikal: from 5.5 to about 7 times smaller than in the pelagic waterside sculpins. Cottocomephorus grewingki and C. inermis, and about 3 times smaller than in groundling deep-water Cotinella boulengeri. This is an extremely small GRSA considering no accessory respiratory organs are present. Scanning electron microscopic observations revealed numerous chloride cells in the epithelium of golomyanka gill lamellae but not in the sculpin lamellae. Chloride cells probably restrict gas exchange in the lamellae considerably. The results suggest that golomyankas have a small oxygen requirement.     

Length–weight relationships for two marine fish species from the Gulf of Oman: Uranoscopus guttatus Cuvier, 1829 and Lagocephalus inermis (Temminck & Schlegel, 1850)

This study presents the first report of length–weight relationships (LWRs) for Uranoscopus guttatus and Lagocephalus inermis from the Iranian coast on the Gulf of Oman. A wide range of body lengths and weights were obtained using samples from non‐selective trawling surveys. The LWRs obtained were W = 41.408L^3.519 and W = 16.525L^2.847 for U. guttatus and L. inermis, respectively.     

Comparative study of two protein-coding regions of mitochondrial DNA from three endemic sculpins (cottoidei) of Lake Baikal

Summary Two protein-coding regions (cytochrome b, ATPase 8, and part of ATPase 6) from mitochondrial DNA of Cottus kessleri, Cottocomephorus grewingki, and Cottocomephorus inermis-Baikalian endemic sculpins—were amplified via polymerase chain reaction, and sequenced. Two novel primers-L8352 (5-TAAAGATTGGTGAC TCCCAACCACC) and H8773 (5-GTAGGGAGT AAGCCCAATATGTT)-were used for the latter region. Phylogenies suggested by sequence divergence of the genes of ATPases appeared to be different from those computed from data for cytochrome b. The time of species branching was estimated as 1–2 million years (Myr) on the basis of merged sequences. Hence, members of the Baikalian cottoid species flock are much more distant from each other than members of the cichlid fish flocks of the great lakes of Africa (0.2 Myr). Topology of the phylogenetic tree does not contradict the relationships derived from morphological data. However, genetic distances suggest that C. grewingki and C. inermis are not sister species, contrary to general belief. Offprint requests to: M.A. Grachev     

A comparison of water loss and gill areas in two supralittoral amphipods from New Zealand

Total gill area and gill distribution were measured for the sandhopper Talorchestia quoyana (Milne-Edwards) and the beach flea Transorchestia chiliensis (Milne-Edwards). For both species the gill structure and proportional area contributed by individual gills was similar. Gill 6 (G6) was the largest, providing 36% of the gill area in Tal. quoyana and 30% in Tr. chiliensis. The gill area/total dry weight relationships were similar, Y = 1.3 X^0.79 for Tal. quoyana and 1.4 X^0.78 for Tr. chiliensis. Small, medium and large amphipods survived >24 h in aerial conditions close to 100% RH at 15 °C. Rates of water loss in desiccating conditions increased with decreasing RH. Lethal water loss exceeded 30% weight loss for both species. Rate of water loss, (R) mg water loss. mg wet wt tissue. h^–1 exposed to 75% RH for Tr. chiliensis was 0.21, resulting in total mortality within 2 h. Medium Tal. quoyana were the most resistant group surviving 4 h exposure to 75% RH with R = 0.08. Differences in desiccation tolerances of the two amphipods are not explained by body water content, gill area relationships or the larger maximal size of T. quoyana. Results were combined with those from other talitrids to examine the relationship between gill area, water content, desiccation habitat and oxygen consumption in aerial and aquatic conditions. There were no consistent relationship between gill area, O₂ uptake and desiccation resistance. Amphipods show compensatory respiratory adaptation with individuals from all habitats, showing similar rates of oxygen uptake, either in air or in water, whichever was their most usual respiratory medium. Q¹⁰ values close to 2.0 were found in all ecomorphological groups. Sandhoppers, including Tal. quoyana, are best able to survive terrestrial conditions associated with a low humidity environment. It is concluded that the water loss characteristics of Tr. chiliensis limit its distribution on sand beaches to areas of high relative humidities.     

Relationship between surplus energy and body weight in fish populations

This paper theoretically analyses the relationship between surplus energy, which is available for either somatic growth or reproduction, and body weight. From the data of metabolism and growth of the biwamasu, Oncorhynchus rhodurus, obtained by Miura et al., a Bernoulli's differential equation is induced to represent the relationship between body weight and the sum of surplus energy and active metabolic rate. Solving this equation gives the amount of surplus energy, f(W_x), as follows:f(W_x) = (αW_x^1−γ+β^1−γ)^1/(1−γ)−W_x, in which α, β and γ are constants and W_x is body weight at age x. The function is applied to ten fish populations and consequently it is found to be useful for a wider age range and a wider variety of fishes than the conventional function.     

Taxonomic review of the <Emphasis Type="Italic">Sebastes inermis</Emphasis> species complex (Scorpaeniformes: Scorpaenidae)

A taxonomic review of three color morphotypes of the Sebastes inermis species complex established the existence of three valid species, viz. S. inermis, S. ventricosus, and S. cheni. The complex is defined by having two sharp lachrymal spines, the head weakly armed with nasal, preocular, supraocular and parietal spines, and the caudal fin not distinctly emarginated. Sebastes inermis, known from southern Hokkaido southward to Kyushu, Japan, and the southern part of the Korean Peninsula, is characterized as follows: body dark red or light brown dorsally and laterally when fresh, pectoral fin extending beyond level of anus when depressed, pectoral-fin rays 15, anal-fin rays 7, pored lateral line scales 36–44 and gill rakers 31–37. Sebastes ventricosus, known from Iwate and Ishikawa Prefecture southward to Kyushu, Japan, and the southern part of the Korean Peninsula, is characterized as follows: body somewhat greenish-black dorsally and dark silver ventrally when fresh, pectoral-fin rays 16, anal-fin rays 7–8, pored lateral line scales 43–49, and gill rakers 35–39. Sebastes cheni, known from Iwate and Akita Pref. southward to Kyushu, Japan, and the southern part of the Korean Peninsula, is characterized as follows: body dark golden-brown dorsally and laterally when fresh, pelvic fin extending beyond anus when depressed, pectoral-fin rays 17, anal-fin rays 8, pored lateral line scales 37–46 and gill rakers 32–37. In the genetic analysis, the presence or absence of two AFLP fragments was completely fixed among the three species. Sebastes tokionis and S. guentheri are regarded as junior synonyms of S. inermis and S. ventricosus, respectively. A lectotype is designated for S. cheni, and a key to the three species of the S. inermis species complex provided.     

Effects of temperature and body size on radiocaesium retention in brown trout, Salmo trutta

1. The elimination rate of radiocaesium in brown trout Salmo trutta L. was determined in the laboratory at four water temperatures (range 4.4–15.6°C). In the experiments three or four homogenous size-groups of fish (mean weights 23–496 g) were studied at each temperature. 2. The brown trout received acute oral doses of ¹³⁴Cs and were killed at intervals for radioactivity counting. The retention versus time curves were composed of two distinct exponential components. The long-lived component was quantitatively the most important for retention of radiocaesium. Elimination rate increased with increasing water temperature and decreased with increasing body weight. 3. The biological half-life of ¹³⁴Cs (T_b, days) was related to fresh body weight (W, g) and water temperature (t, °C) by the equation: T_b= 290 ×W°.¹⁷⁶× e-°.^106×t. The elimination rate of Cs could be predicted from weight-specific metabolic rate as given by Elliott's equations for brown trout.     

4种弹涂鱼鳃的形态度量学比较及其生态学意义

通过对背眼虎鱼亚科中薄氏大弹涂鱼(Boleophthalmus boddarti)、青弹涂鱼(Scartelaos histophorus)、新几内亚弹涂鱼(Periophthalmus novaeguineaensis)和点弹涂鱼(P.spilotus)3属4种弹涂鱼鳃参数的测定,比较了各种之间鳃的形态度量学差异。结果表明,4种弹涂鱼的鳃参数(Y)与其体重(W)均符合方程logY=log a+b logW,且各鳃参数与体重的相关性显著(R2=0.50～0.98,P0.05)。等体重的弹涂鱼相比较,青弹涂鱼的总鳃丝数、总鳃丝长(mm)、鳃丝一侧鳃小片数(/mm)、总鳃面积(mm2)和相对鳃面积(mm2/g)均最大,薄氏大弹涂鱼相应鳃参数次之,新几内亚弹涂鱼和点弹涂鱼相应鳃参数较小。弹涂鱼鳃结构的这种梯度退化,表明青弹涂鱼和薄氏大弹涂鱼水生性较强,而新几内亚弹涂鱼和点弹涂鱼陆生性较强。4种弹涂鱼的总鳃丝长和总鳃面积明显小于其他等体重水生鱼类,这与弹涂鱼的两栖生活特征相符。     

First record of Chonopeltis inermis Thiele, 1900 (Crustacea: Branchiura) in the Limpopo River System with notes on its morphology

Specimens of Chonopeltis collected from the gill chambers of the snake catfish Clarias theodorae in the Luphephe River, a tributary of the Limpopo in northern Transvaal, showed close resemblance to C. inermis Thiele, 1900 previously only recorded from Lake Malawi. Comparative scanning electron microscopical studies on this material and specimens of C. inermis on loan from The Natural History Museum, London showed beyond doubt that C. inermis also occurs in the Limpopo System. This implies that it dispersed across a watershed and successfully established in a different water system.     

Correlated Responses in Male Reproductive Traits in Mice Selected for Litter Size and Body Weight

Correlated responses in male reproductive traits were determined at 4, 6 and 8 weeks of age in lines of mice selected for large litter size (L⁺), large 6-week body weight (W⁺), large litter size and small body weight (L⁺W^-) and small litter size and large body weight (L^-W⁺), and in an unselected control (K). Concentration of serum testosterone and weights of testes, seminal vesicles, epididymides and adrenal glands increased with age. Line differences in testosterone concentration were not detected. L⁺ and W⁺ males exhibited positive correlated responses in testes, epididymides and seminal vescile weights. Testis weight adjusted for body weight was significantly larger for L⁺ than controls and approached significance for W⁺. Realized genetic correlation betestis weight and litter size was 0.60 ± 0.04, and the realized partial genetic correlation holding body weight constant was 0.42. Therefore, pleiotropic loci, acting via the hypothalamic-pituitary axis, affect testis weight and litter size independently of body weight. Additionally, genes influencing overall growth have a pleiotropic effect on testis weight and litter size in mice; the realized genetic correlations of body weight with testis weight and with litter size were 0.60 ± 0.03 and 0.52 ± 0.10. Testis weight increased in both L⁺W^- and L^-W⁺ males. The positive correlated response in L⁺W^- may have resulted from changes in frequency of genes controlling reproductive processes; whereas, in L^-W⁺ it could have been the result of changes in the frequency of genes associated with body weight.     

Body size and temperature dependence of routine metabolic rate and critical oxygen concentration in larvae and juveniles of the round crucian carp Carassius auratus grandoculis Temminck & Schlegel 1846

Routine metabolic rate (RMR, mgO₂ g^?1 h^?1) and critical oxygen concentration (Pc, a hypoxia tolerance indicator, mgO₂ L^?1) were determined in larvae and juveniles of round crucian carp, Carassius auratus grandoculis Temminck & Schlegel 1846, by measuring oxygen consumption at 15°C, 20°C, and 30°C. In addition, the dependence of RMR and Pc on fish body weight (W, g) and temperature (T, °C) was examined to construct minimal mathematical models. RMR depended on W and showed smaller values in larger individuals. RMR was different among the three temperature conditions and showed higher values at higher temperatures. Pc was significantly related to W and was low in larger individuals; that is, larger individuals had a higher hypoxia tolerance. In contrast, Pc was independent of temperature, implying that seasonal temperature fluctuations do not cause seasonal disequilibrium of hypoxia tolerance in round crucian carp. The RMR and Pc models were RMR = 0.0674W^?0.193e^0.0562T and Pc = 1.35W^?0.107, respectively. The metabolic information clarified in this study is essential for habitat quality assessments and aquaculture management of this species.     

Action of the cubitus interruptus-wallace mutant in Drosophila melanogaster: A study of leg morphology on mosaic and haplo-4 flies

The fourth chromosome mutant cubitus interruptus-Wallace(ci^W) produces leg, wing, and body bristle aberrations. The effect on the wing is similar to that produced by cubitus interruptus-dominant (ci^D) which also has an influence on larval segmentation indicating that it has a regulatory function. Leg morphology of haplo-4, ci^W, and mosaic haplo-4:diplo-4, ci/ci⁺ flies was examined in an attempt to distinguish between a structural and a regulatory function by ci^W. Aberrations recovered include failure of segment elongation, intersegmental gaps, duplication of bristles, and segments that are shorter than normal and of greater than normal diameter. Many of these effects are localized, suggesting that ci^W may act to maintain cell positional reference. Increased local cell proliferation appears to be one manifestation of loss of the normal function.     

Modelling the nutritional ecology of ungulate herbivores: evolution of body size and competitive interactions

Summary A simulation model is used to quantify relationships between diet quality, digestive processes and body weight in ungulate herbivores. Retention time of food in the digestive tract is shown by regression to scale with W^0.27, and to be longer in ruminants than in hindgut fermenters. Allometric relationships between whole gut mean retention time (MRT, h) and weight (W) were: MRT=9.4 W^0.255 (r ²=0.80) for hindgut fermenters and MRT=15.3 W^0.251 (r ²=0.76) in ruminants. Longer retention of ingesta by large-bodied ruminants and hindgut fermenters increases digestive efficiency relative to small animals and permits them to survive on lower-quality foods. Compared with ruminants, hindgut fermenters' faster throughput is an advantage which outweighs their lower digestive efficiency, particularly on poor quality foods, provided that food resources are not limiting. This suggests that the predominance of ruminants in the middle range of body weights results from their more efficient use of scarce resources under conditions of resource depletion. Considering only physical limitations on intake, the model shows that the allometric coefficient which scales energy intake to body mass is 0.88 in ruminants and 0.82 in hindgut fermenters. The advantages of large body size are countered by disadvantages where food quantity is limited, and we suggest that the upper limit to ungulate body size is determined by the ability to extract nutrients from feeding niches during the nadir of the seasonal cycle of resource quality and abundance.     

Cube law, condition factor and weight–length relationships: history, meta-analysis and recommendations

This study presents a historical review, a meta‐analysis, and recommendations for users about weight–length relationships, condition factors and relative weight equations. The historical review traces the developments of the respective concepts. The meta‐analysis explores 3929 weight–length relationships of the type W = aL^b for 1773 species of fishes. It shows that 82% of the variance in a plot of log a over b can be explained by allometric versus isometric growth patterns and by different body shapes of the respective species. Across species median b = 3.03 is significantly larger than 3.0, thus indicating a tendency towards slightly positive‐allometric growth (increase in relative body thickness or plumpness) in most fishes. The expected range of 2.5 < b < 3.5 is confirmed. Mean estimates of b outside this range are often based on only one or two weight–length relationships per species. However, true cases of strong allometric growth do exist and three examples are given. Within species, a plot of log a vs b can be used to detect outliers in weight–length relationships. An equation to calculate mean condition factors from weight–length relationships is given as K_mean = 100aL^b?3. Relative weight W_rm = 100W/(a_mL^bm) can be used for comparing the condition of individuals across populations, where a_m is the geometric mean of a and b_m is the mean of b across all available weight–length relationships for a given species. Twelve recommendations for proper use and presentation of weight–length relationships, condition factors and relative weight are given.     

Trophic ecology and gill raker morphology of seven catostomid species in Iowa rivers

Understanding the trophic ecology of closely‐related species is important for providing insight on inter‐specific competition and resource partitioning. Although catostomids often dominate fish assemblages in lotic systems, little research has been conducted on their ecology. This study was developed to provide information on the trophic ecology of catostomids in several Iowa rivers. Food habits, diet overlap, and gill raker morphology were examined for highfin carpsucker Carpiodes velifer, quillback C. cyprinus, river carpsucker C. carpio, golden redhorse Moxostoma erythrurum, shorthead redhorse M. macrolepidotum, silver redhorse M. anisurum, and northern hogsucker Hypentelium nigricans sampled from four Iowa rivers (2009). Diet overlap among all species was calculated with Morista’s index (C). Food habit niche width was quantified with Levin’s index (B) and similarity in gill raker morphology was compared with analysis of covariance. Values from Morista’s index suggested significant overlap in the diets of highfin carpsucker and river carpsucker (C = 0.81), quillback and river carpsucker (C = 0.66), and shorthead redhorse and silver redhorse (C = 0.67). Levin’s index indicated that golden redhorse (B = 0.32), quillback (B = 0.53), and river carpsucker (B = 0.41) had the most generalized feeding strategies as their food niche widths were substantially wider than the other species. Gill raker length and spacing were positively correlated with the standard length of the fish for all species (gill raker length: r² = 0.67–0.88, P ≤ 0.01; gill raker spacing: r² = 0.63–0.73, P ≤ 0.01). Slopes of regression of gill raker length and spacing to standard lengths were significantly (P ≤ 0.05) different among species, indicating that rates of change in gill raker morphology with body length varied among species. Differences in gill raker morphology likely allow catostomids to partition resources and reduce competitive interactions.     

Obesity does not increase external mechanical work per kilogram body mass during walking

Walking is the most common type of physical activity prescribed for the treatment of obesity. The net metabolic rate during level walking (W/kg) is ~10% greater in obese vs. normal weight adults. External mechanical work (W_ext) is one of the primary determinants of the metabolic cost of walking, but the effects of obesity on W_ext have not been clearly established. The purpose of this study was to compare W_ext between obese and normal weight adults across a range of walking speeds. We hypothesized that W_ext (J/step) would be greater in obese adults but W_ext normalized to body mass would be similar in obese and normal weight adults. We collected right leg three-dimensional ground reaction forces (GRF) while twenty adults (10 obese, BMI=35.6 kg/m² and 10 normal weight, BMI=22.1 kg/m²) walked on a level, dual-belt force measuring treadmill at six speeds (0.50–1.75 m/s). We used the individual limb method (ILM) to calculate external work done on the center of mass. Absolute W_ext (J/step) was greater in obese vs. normal weight adults at each walking speed, but relative W_ext (J/step/kg) was similar between the groups. Step frequencies were not different. These results suggest that W_ext is not responsible for the greater metabolic cost of walking (W/kg) in moderately obese adults.     

Is maximum sustainable yield independent of body size for mammals (and others)?

Summary Provided carrying capacity (K) for non-primate mammals scales with the –0.75 power of adult body weight (W), MSY (in weight) should be approximately one-sixth ofC, whereC is defined byK =CW ^–0.75.     

The consequences of seasonal reproductive strategies for the interpretation of settlement trials

Many temperate marine organisms, including the boreo‐arctic barnacle Semibalanus balanoides, have well‐delineated reproductive seasons. The aim of this study was to examine the consequences of small changes in deployment time of settlement experiments within such a settlement season upon long term demographic parameters. Repeat deployments of settlement tiles were made at 1‐week intervals for six weeks during the April 1996 S. balanoides settlement season in the Clyde Sea, UK. The colonies were harvested in November 1996 and density, mortality, fecundity, morphology, and dry weight of eggs, somatic tissue and shell determined. There were non‐linear relationships between density (D) and deployment time (W) (D = 1.11+1.38W‐0.24W ²), and between morphology (M) and deployment time (M = 21.2 + 0.54W‐0.13W ²). There were linear relationships between mortality (L) and deployment time (L = 61.49 ‐ 7.99 W), body weight (B) and deployment time (B = 0.0050 + 0.0012W), shell (S) dry weight and deployment time (S = 0.17 + 0.02W). Egg dry weight did not vary significantly with deployment time. This study demonstrates how small changes in deployment time of settlement can have substantial consequences on the long‐term demographic processes within single species populations. The relationships between deployment, density and other demographic parameters are discussed, as are strategies for dealing with the confounding effects of reproduction.