Body Standard Length Research Articles

Chloride currents in cones modify feedback from horizontal cells to cones in goldfish retina

In neuronal systems, excitation and inhibition must be well balanced to ensure reliable information transfer. The cone/horizontal cell (HC) interaction in the retina is an example of this. Because natural scenes encompass an enormous intensity range both in temporal and spatial domains, the balance between excitation and inhibition in the outer retina needs to be adaptable. How this is achieved is unknown. Using electrophysiological techniques in the isolated retina of the goldfish, it was found that opening Ca(2+)-dependent Cl(-) channels in recorded cones reduced the size of feedback responses measured in both cones and HCs. Furthermore, we show that cones express Cl(-) channels that are gated by GABA released from HCs. Similar to activation of I(Cl(Ca)), opening of these GABA-gated Cl(-) channels reduced the size of light-induced feedback responses both in cones and HCs. Conversely, application of picrotoxin, a blocker of GABA(A) and GABA(C) receptors, had the opposite effect. In addition, reducing GABA release from HCs by blocking GABA transporters also led to an increase in the size of feedback. Because the independent manipulation of Ca(2+)-dependent Cl(-) currents in individual cones yielded results comparable to bath-applied GABA, it was concluded that activation of either Cl(-) current by itself is sufficient to reduce the size of HC feedback. However, additional effects of GABA on outer retinal processing cannot be excluded. These results can be accounted for by an ephaptic feedback model in which a cone Cl(-) current shunts the current flow in the synaptic cleft. The Ca(2+)-dependent Cl(-) current might be essential to set the initial balance between the feedforward and the feedback signals active in the cone HC synapse. It prevents that strong feedback from HCs to cones flood the cone with Ca(2)(+). Modulation of the feedback strength by GABA might play a role during light/dark adaptation, adjusting the amount of negative feedback to the signal to noise ratio of the cone output.

Heritability of cortisol response to confinement stress in European sea bass dicentrarchus labrax

BackgroundIn fish, the most studied production traits in terms of heritability are body weight or growth, stress or disease resistance, while heritability of cortisol levels, widely used as a measure of response to stress, is less studied. In this study, we have estimated heritabilities of two growth traits (body weight and length) and of cortisol response to confinement stress in the European sea bass.FindingsThe F1 progeny analysed (n = 922) belonged to a small effective breeding population with contributions from an unbalanced family structure of just 10 males and 2 females. Heritability values ranged from 0.54 (±0.21) for body weight to 0.65 (±0.22) for standard body length and were low for cortisol response i.e. 0.08 (±0.06). Genetic correlations were positive (0.94) between standard body length and body weight and negative between cortisol and body weight and between cortisol and standard body length (−0.60 and −0.55, respectively).ConclusionThis study confirms that in European sea bass, heritability of growth-related traits is high and that selection on such traits has potential. However, heritability of cortisol response to stress is low in European sea bass and since it is known to vary greatly among species, further studies are necessary to understand the reasons for these differences.

Assessment of nutritional condition indices across reproductive states in the striped dolphin ( Stenella coeruleoalba)

The aim of this study was to identify reliable and accurate nutritional condition indices in small cetaceans. Samples from 115 stranded striped dolphins along the eastern coast of Spain (Western Mediterranean) were collected during two die-off events (1990–1991 and 2007–2008), including animals of different reproductive states and varying nutritional conditions. We segmented the data according to sex and reproductive condition, because energetic demands vary considerably among these collectives, and they were considered a good sample to represent groups with different nutritional conditions. We compared five variables as indices to measure nutritional condition. They were: a) blubber lipid content, b) blubber trunk lipid mass (BTLM), c) muscle/blubber trunk mass ratio, d) maximum girth, and e) blubber thickness. Since the dolphins differed in size, each variable was regressed against standard body length, and the residuals of these regressions were used as indices of nutritional condition. Only the mean residuals of BTLM (p < 0.001) and blubber lipid content (p = 0.005) varied significantly among reproductive classes. However, the mean residuals of BTLM appeared to be the most sensitive index of nutritional condition, because it discriminated better among reproductive states.

Fin condition in intensively cultured Eurasian perch (Perca fluviatilis)

Abstract. Condition of all fins was assessed in intensively cultured perch (n = 300) in comparison with control pond-reared perch (n = 30). Measurements of maximum fins length as well as a four point photographic scale were used. No damage to any fin was visually observed in the pond-reared group. The first dorsal fin showed the least damage in cultured perch with 93 % of fish demonstrating no erosion. The most affected were paired fins, with only 7 % and 2 % of pectoral and ventral fins, respectively, being non-eroded. No difference between culture systems was found in fin length for the first dorsal and the caudal fin. Pectoral, second dorsal, ventral, and anal fins of intensively cultured perch showed reductions up to 52, 49, 35, and 28 %, respectively. The relationship between fin lengths and standard body length (SL) were described for both groups (SL range 104–170 mm). Results of this study are discussed in relation to aesthetic, welfare and fish survival issues.

Comparative morphology and cytology of the alimentary tract in lizardfishes (Teleostei, Aulopiformes, Synodontidae)

AbstractFishelson, L., Golani, D., Russell, B., Galil, B. and Goren, M. 2012. Comparative morphology and cytology of the alimentary tract in lizardfishes (Teleostei, Aulopiformes, Synodontidae). —Acta Zoologica (Stockholm) 93: 308–318.This study compares the morphology and cytology of the alimentary tract in several species of lizardfishes (Synodontidae, Teleostei) of the genera Saurida, Synodus, and Trachinocephalus, in relation to their diets and bathymetric distribution. All the studied species feature a large, pouch‐like stomach, with the intestine beginning at the stomach’s anterior apex, adjacent to the esophageal opening. In the more ‘microphagous’Synodus spp. and Trachinocephalus, the intestine bends twice before reaching the anus, whereas in the more ‘macrophagous’Saurida spp., the intestine extends straight to the anus. The species differ also in the number and form of their pyloric ceca, the length of the intestine and in the percentile relationship between stomach length and standard body length. Along the alimentary tract folds and villi protrude into the lumen, their numbers differing on various sites of the tract. Three cell types make up the gastric gland system: (1) pyramidal cells forming the tubular gastric glands in the lamina propria; among them are large, pale secretary cells; (2) groups of neck cells that surround the pits of the tubules; and (3) groups of large and granule‐rich cells at the end portion of the stomach. All species are carnivorous and uniform in morphology, the differences in the alimentary tract found between the more shallow‐water species of Synodus and Trachinocephalus, and the deeper‐dwelling Saurida, seem to be only partly correlated with the differences in diet.

Accumulation features of trace elements in mass-stranded harbor seals (Phoca vitulina) in the North Sea coast in 2002: The body distribution and association with growth and nutrition status

Body distribution and growth- and nutritional status-dependent accumulation of 21 trace elements were investigated in harbor seals (Phoca vitulina) stranded in the North Sea coast in 2002. Higher concentrations and burdens of Mn, Se, Mo, Ag, Sn, Hg, and Bi in the liver, Cd in the kidney, As in the blubber, and Co, Sr, and Ba in the bone were observed. Significant positive correlations of hepatic Se, Mo, Ag, Cd, Sn, Hg, Tl, and Bi with standard body length were found, while significant negative relationships were detected for Mn, As, Rb, Sr, and Sb in the liver. Concentrations of Co, Se, Sr, Sn, Hg, and Bi in the liver, V, Sr, Ag, Sn, and Hg in the kidney, V, Mn, Co, Rb, Sr, Sn, Ba, and Pb in the blubber increased with decreasing blubber thickness of harbor seals, indicating enrichment of these elements in the target tissue by emaciation.

Mapping QTL for an Adaptive Trait: The Length of Caudal Fin in Lates calcarifer

The caudal fin represents a fundamental design feature of fishes and plays an important role in locomotor dynamics in fishes. The shape of caudal is an important parameter in traditional systematics. However, little is known about genes involved in the development of different forms of caudal fins. This study was conducted to identify and map quantitative trait loci (QTL) affecting the length of caudal fin and the ratio between tail length and standard body length in Asian seabass (Lates calcarifer). One F1 family containing 380 offspring was generated by crossing two unrelated individuals. One hundred and seventeen microsatellites almost evenly distributed along the whole genome were genotyped. Length of caudal fin at 90 days post-hatch was measured. QTL analysis detected six significant (genome-wide significant) and two suggestive (linkage-group-wide significant) QTL on seven linkage groups. The six significant QTL explained 5.5-16.6% of the phenotypic variance, suggesting these traits were controlled by multiple genes. Comparative genomics analysis identified several potential candidate genes for the length of caudal fin. The QTL for the length of caudal fin detected for the first time in marine fish may provide a starting point for the future identification of genes involved in the development of different forms of caudal fins in fishes.

Winter diet and digestive tract of the Golden Pheasant (Chrysolophus pictus) in the Qinling Mountains, China

The winter diet and morphological structure of the gastrointestinal tract of the Golden Pheasant (Chrysolophus pictus) was investigated in the Qinling Mountains, Shaanxi Province in 2002/2003. Individual food items in crops were identified by species, where possible, using standard taxonomic methods. The Golden Pheasant consumes exclusively vegetarian foods in the winter, of at least 14 plant species, such as crops and other vegetable species. The digestive tract of the Golden Pheasant is composed of an oesophagus, a stomach, a relatively long intestine measuring 3.4 × standard body length, two fully-developed caeca and a relatively short colon, typical for herbivorous birds. Pebbles of different sizes (0.5-3 mm in diameter) were very frequent in the gizzard. The average dry weight of the pebbles was 10.4±2.5 g and was positively correlated with the weight of digesta in the gizzard (Pearson r=0.747, p＜0.01, n=37). The mucosa surface pH of the digestive tract of the Golden Pheasant was slightly acidic, but higher in the crop and gizzard.

Distribution and species composition of juvenile and adult scombropids (Teleostei, Scombropidae) in Japanese coastal waters

Two scombropid fishes, Scombrops boops and Scombrops gilberti, are closely related and commercially important species in Japan. These species are often confused in commercial markets because of their morphological similarity. In this study, scombropid specimens collected from various Japanese coastal waters were subjected to polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis and phylogenetic analysis of the 16S rRNA gene in mitochondrial DNA. These analyses showed that all the scombropid specimens collected from localities in the Sea of Japan were identified as S. boops, whereas those from the Pacific Ocean included two species, S. boops and S. gilberti. Almost all juvenile (<200 mm standard body length, S(L)) S. gilberti originated from the Pacific coastal waters of the northern Japan, whereas adults (>400 mm S(L)) were found only in deep water off the Izu Peninsula to the Izu Islands. This suggests that S. gilberti might migrate extensively during its life cycle. In addition, differences in the number of specimens and the distribution between the two species suggest that S. gilberti is less abundant than S. boops in Japanese waters.

First mass stranding of Risso's dolphins ( Grampus griseus) in Peru and its destiny as food and bait

The first mass stranding of Risso's dolphins Grampus griseus on the Peruvian coast occurred on Pozo de Lizas Beach (17°42′30.3″S 71°18′48.7″W), port of Ilo, Department of Moquegua, southern Peru, between 7 and 8 June 2007. At least 14 Risso's dolphins were stranded along 1.5 km of beach. Just 7 of them could be sized and 8 sexed; this group was composed of 7 males and a single female plus a juvenile of undetermined sex. Mean standard body length of the males was 299.67 cm (SD: 9.91 cm, range: 292–317 cm) and the female measured 289 cm. The entire group, including four individuals found alive, was illegally butchered by the local people to use the meat as food, while other remains were used as bait in the pelagic long-line fishery. This record fills a distributional gap of about 1000 km in the known distribution of the species between central Peru and northern Chile. Additional education is required for improved conservation strategies in future cetacean strandings.

Spawning Migration and Population Condition of Twaite Shad (Alosa fallax, Lacépède 1803) in Lithuania

Basic biological information for a twaite shad population ( Alosa fallax , Lacepede 1803) is presented based on a 2-year study involving 273 adult and 18 juveniles specimens. The fish were caught in the Curonian lagoon and coastal zone of the Baltic Sea. At the end of July, 2004 was observed intensive and record late spawning of the twaite shad. At the end of May, 2005 was observed the beginning of spawning migration of this fish . Twaite shad was one of the key fish species caught with 38-50 mm mesh size nets at the material sampling location. The CPUE in different mesh size gill nets fluctuated from 2.7 to 32 individuals. In the spawning shoal male individuals were predominant. The standard body length of twaite shad females varied from 322 to 430 mm. The standard body length of males varied from 280 to 390 mm. Twaite shad ranged from 2+ to 9+ years, but the majority were from 4+ to 7+ years. Females exhibited higher CF and GSI values than males. Young fish were caught at 7 stations out of 17, although their abundance was not high. Besides the twaite shad, there were juveniles of 18 more fish species caught in the coastal zone.

Growth and age at sexual maturity of South American sea lions

The average age at sexual maturity ( ASM) is an important parameter for evaluating the reproductive potential or status of a population. South American sea lions, Otaria flavescens in Patagonia (Argentina) were exploited and reduced to less than 10% of pre-exploitation numbers. At present, the population is recovering at a rate of 6%. In this paper, we studied growth and age at sexual maturity of South American sea lions in the south-western south Atlantic by examining 219 individuals (females and males) collected between 1989-2008. Individuals were aged by counting growth layer groups in tooth sections, standard body length was measured and male and female reproductive organs were examined macroscopically and histologically to establish individual sexual maturity. Maximum recorded length for males and females was 264 cm and 200 cm, respectively, and maximum ages 19 and 21 yrs. ASM defined as the age where 50% of females are mature, was estimated at 4.8±0.5 years old, corresponding to a mean SL of 147 cm, about 81% of their asymptotic length. First observed ovulation occurred during the 4th year, first birth may occur between 4 and 5 years old. Males physiologically mature between 4-6 years, but the size of the testes shows that all males became sexually mature by the age of 9 years when they reach a mean SL of 212 cm, about 86% of their asymptotic body length. The present information on ASM and growth of O. flavescens will improve the development of population dynamics models, to investigate the impact of recovering sea lions populations on its marine environment, as well as its trophic interactions with commercial fisheries.

Effects of substrate color, light intensity and temperature on survival and skin color change of juvenile seahorses, Hippocampus erectus Perry, 1810

Seahorses are popular ornamental fish for marine aquaria, with more colorful individuals commanding higher prices. We investigated the effects of substrate color, light intensity and water temperature on the survival and skin color change of the juvenile seahorse, Hippocampus erectus. During the 6-week study, the juveniles cultured with substrates of mixed colors (green and orange, green and red) had higher survival and color change rates than those with a single color substrate (green, orange, red, or black, F 5, 18 = 2.764, F 5, 18 = 56.225, P < 0.05). Color change rate of the juveniles increased with increasing light intensity (500, 1000, 1500, 2000, 2500 and 3000 lx) with juveniles cultured at 500 lx had the highest survival rate (85.35 ± 5.18%). The wet weight, standard body length and age of the juveniles that began to change their skin color ranged from 0.054 ± 0.007 g, 3.12 ± 0.31 cm and 17.26 ± 2.23 days post partum (green and orange substrate mixture) to 0.082 ± 0.013 g, 3.68 ± 0.59 cm and 25.66 ± 6.21 days post partum (black) among the substrate color treatments; and from 0.043 ± 0.009 g, 3.09 ± 0.62 cm, and 14.57 ± 2.35 days post partum (3000 lx) to 0.067 ± 0.008 g, 3.87 ± 0.49 cm, and 18.41 ± 3.73 days post partum (500 lx) among the light intensity treatments. Survival rate and color change rate of the juveniles cultured at three temperatures (23 °C, 26 °C, and 29 °C) differed significantly after 5 weeks ( F 2, 9 = 11.053, P < 0.05). The juveniles cultured at the temperature of 29 °C had the highest color change rate of 80.43 ± 4.27%. These results demonstrate that appropriate mixed color substrate, light intensity and temperature can improve the survival and skin color change rates of the juvenile H. erectus, thus affecting their market value.

The First Record of the Fourhorn Sculpin ((Triglopsis Quadricornis Linnaeus, 1758): Actinopterygii: Scorpaeniformes: Cottidae) in the Southeastern Part of the Baltic Sea (Lithuanian Coastal Zone)

The fourhorn sculpin (Triglopsis quadricornis), a fish of the northern Baltic Sea waters, was caught on April 14, 2009. It is the first record of this species in the southeastern Baltic Sea (ICES Subdivision 26). The fish was caught in the period of hydrological spring, during seasonal thermocline formation. The standard body length of the caught specimen was 275 mm and weight 355 g. Main morphometric characters: D1 – VIII, D2 – 14, V – 3, P – 16, A – 14, C – 14. It was a female with gonads at maturity stage V. Parasitic helminths typical of coldwater fishes of the northern and southeastern Baltic Sea were detected in its intestine: eight unencysted larvae (L3) of roundworms (Hysterothylacium aduncum Rudolphi, 1809), 19 encapsulated larvae of acanthocephalans (Corynosoma semerme Forssell, 1904) and one larva of Corynosoma strumosum (Rudolphi 1802). There were no remains of nutritive organisms found in the stomach and intestine of the fourhorn sculpin. From a biological viewpoint, this coldwater fish is to...

Feeding habits of hatchery-reared larvae of greater amberjack Seriola dumerili

To obtain basic knowledge on the feeding habits of greater amberjack Seriola dumerili larvae during the early phase of seed production, larvae were reared until 15–20 days post hatching. Larvae were fed on rotifers Brachionus plicatilis sp. complex with different body sizes, i.e., super small type, small type, and large type rotifers, and the survival rate, standard body length (SBL) and gut contents of the larvae were examined. There were no significant effects of rotifer size on survival and growth of greater amberjack larvae, except for the smallest SBL of larvae fed with super small type rotifers. The body sizes (lorica length and lorica width) of rotifers ingested by larvae did not change in accordance with the growth in larval body size and mouth size from the onset of feeding to ~7.6 mm SBL, despite the larvae having a chance to prey on larger body size rotifers in the tanks. Counting the number of rotifer eggs in the guts revealed that larvae≥4.5 mm SBL appeared to selectively prey on egg-bearing rotifers, whose body sizes are relatively large among the rotifer populations in the tanks, indicating an ontogenic change in the feeding habit of greater amberjack larvae.

Dynamics of three-axle-one-unit vehicles with self-steering single axle

This paper proposes a new rail vehicle concept: a ‘three-axles-one-unit’ vehicle, with a self-steering single axle. Usually, a single-axle vehicle requires a short and wide car body, which is a system design of the next generation of railway vehicles. The authors propose a new ‘three-axle-one-unit’ vehicle steering a single-axle truck for the railways. This proposed vehicle uses three trucks and has the standard body length of a conventional train. It has the merit of decreasing elastic-body vibration by using a lightweight car body and by setting a truck in the middle of the car body. This system design can provide high performance with respect to stability, curving performance, and axle load limitation. Analyses were made with multi-body dynamic simulations and the basic characteristics were cleared. Finally, 1/10-scale model was made and tested. The proposed vehicle's potential for high performance was proved from running experiments, including curving.

Effects of two parasites, Schistocephalus solidus (Cestoda) and Bunodera spp. (Trematoda), on the escape fast‐start performance of three‐spined sticklebacks

The fast‐start performance of three‐spined sticklebacks Gasterosteus aculeatus infected with Schistocephalus solidus and Bunodera spp. was determined and two distinct fast‐start responses (A and B) were observed. ‘A’ starts were of higher flexibility than B and three‐way ANOVA showed significant effects of A and B starts (P &lt; 0·05), time (P &lt; 0·05) and per cent standard body length, LS (P &lt; 0·05) on the orientation angle (angle of an individual segment of the fish with respect to the direction of travel). Schistocephalus solidus infection reduced maximum velocity (P &lt; 0·05) and maximum acceleration (P &lt; 0·05) of infected fish. Uninfected fish and fish infected with S. solidus up to a parasite index (parasite mass divided by the sum of fish and parasite mass) of 0·1 executed both types. Infected fish exclusively executed B starts for parasite index between 0·1 and 0·2. This was not due to a reduction in body flexibility associated with mechanical obstruction caused by S. solidus as no significant difference in the ratios of body width (P &gt; 0·05) or depth (P &gt; 0·05) to LS were found between uninfected and infected fish. At a parasite index &gt;0·2, infected fish were unable to perform escape fast‐starts increasing the likelihood of predation by their definitive hosts such as loons or belted kingfishers. Three‐spined sticklebacks infected with S. solidus with a parasite index of c. 0·2–0·3, however, were compromised by a suite of behavioural (e.g. increased foraging activity and amount of food consumed, increased risk associated with feeding and increased response latency to predatory stimuli), physiological (e.g. increased rate of oxygen consumption, slower growth, delayed sexual maturation and breeding success) and biomechanical (e.g. decreased fast‐start performance) factors. Bunodera spp. did not affect the escape fast‐start performance of three‐spined sticklebacks and no significant difference for maximum velocity (P &gt; 0·05) and maximum acceleration (P &gt; 0·05) was found.

Gestational stage sensitivity to ultrasound effect on postnatal growth and development of mice

An experiment was conducted to find out whether ultrasound exposure leads to changes in postnatal growth and development in the mouse. A total of 15 pregnant Swiss albino mice were exposed to diagnostic levels of ultrasound (3.5 MHz, 65 mW/cm2, I(SPTP) = 1 mW/cm2 Intensity(Spatial Peak-Temporal Peak), I(SATA) = 240 mW/cm2 Intensity(Spatial Average-Temporal Average)) for 30 min for a single day between days 10 and 18 of gestation (GD 10-18). Virgin female mice were placed with same age group males for mating in the ratio 2 females : 1 male and examined the next morning for the presence of vaginal plug, a sign of successful copulation. The females with vaginal plugs were separated and labeled as 0-day pregnant. Maternal vaginal temperature was also measured. A sham exposed control group of 15 pregnant mice was maintained for comparison. All exposed as well as control animals were left to complete gestation and parturition. Their offspring were used in our further studies. They were monitored during early postnatal life for standard developmental markers, postnatal mortality, body weight, body length, head length, and head width, and growth restriction was recorded up to 6 weeks of age. An exposure to ultrasound induced nonsignificant deviations in the maternal vaginal temperature or developmental markers. Significant low birth weight was observed in the present study, after exposure at GD 11, 12, 14, and 16. However, 14 and 16 days postcoitus during the fetal period appears to be the most sensitive to the ultrasound effect, in view of the number of different effects as well as severity of most of the observed effects when exposed on these gestation days. The results indicate that diagnostic ultrasound can induce harmful effects on mouse growth and development when given at certain critical periods of gestation.

Organ Weights and Growth Profiles in Bottlenose Dolphins (&lt;I&gt;Tursiops truncatus&lt;/I&gt;) from the Northwestern Gulf of Mexico

Systematic necropsies were performed on 63 bottlenose dolphins (Tursiops truncatus), and data on organ mass, standard body length (SBL), body mass (BM), gender, sexual maturity, and age were measured and/or estimated. Animals were extremely fresh and recovered from along the Texas and Louisiana coastline in the northwestern Gulf of Mexico. Organ reference tables were established for this species to facilitate comparisons with other bottlenose dolphins and to provide a baseline for other cetacean species. Organs examined included lungs, adrenal glands, kidneys, testes, ovaries, heart, liver, pancreas, brain, pituitary, thyroid, thymus, and spleen. Individuals were separated into three size classes: 225 cm, based on SBL to further facilitate comparisons. Growth rates of length and mass were described using Gompertz nonlinear models as a function of gender. No sexual dimorphism was identified in BM or organ weights, and SBL was only significantly larger for older mature males. SBL and BM were strongly correlated with age when all animals were included in analyses, although this is not an accurate predictor of age, especially in older individuals. Organ weights were significantly correlated with both SBL (except thymus and spleen) and BM (except left ovary, spleen, and thymus). Age was significantly correlated with all organ weights (except thymus, thyroid, and ovaries). There were no significant differences in the weight of any paired organs (adrenal glands, kidneys, lungs, ovaries, testes), and all were significantly correlated with BM. These data on organ weights of bottlenose dolphins, when interpreted with SBL, BM, and age, are significant tools for pathologists and veterinarians interpreting animal health status.

Pectoral fin development in the Baikalian viviparous golomyankas (Comephoridae; Cottoidei), with a remark on eggs and embryos of Comephorus baicalensis (Pallas)

Measurements of pectoral fin (PF) growth in relation to standard body length (SL) for Comephorus dybowskii (SL: 14-126 mm) and C. baicalensis (SL: 22-173 mm) were made and compared with corresponding data obtained for 13 other Baikalian cottoid species (sculpins). The allometry for the PF/SL relationships (Y = a + bX) is clearly biphasic. Expressed in percentages, these values for the larval period of C. dybowskii [Yp = -28.886 + (2.419X)] are much higher than for C. baicalensis [Yp = -11.904 + (1.233X)]. The postnatal period of development of the golomyanka up to 30-35 mm SL is considered to be the larval stage. In the postlarval period, growth of pectoral fin and the body in C. dybowskii are directly proportional [Yp' = 48.92 + (-0.009X)] whereas in C. baicalensis they rise slightly [Yp' = 30.966 + (0.0505X)]. Absence of the air bladder characterizes all Baikalian cottoid species, including the golomyankas. Various species of the golomyanka differ in the ways of obtaining neutral buoyancy. It is supposed that large pectoral fins guarantee behavioural buoyancy in small species such as C. dybowskii, whereas in C. baicalensis, obtaining much larger body size but lower PFp/SL index, the buoyancy is gained mainly due to the accumulation of large amount of lipids. This paper also documents the ovary and advanced embryos of C. baicalensis.