Buoyancy Response to Changes in Water Velocity and Its Function in Creek Chub (Semotilus atromaculatus)

1978 ◽  
Vol 35 (3) ◽  
pp. 295-299 ◽  
Author(s):  
Gordon Berezay ◽  
John H. Gee
Keyword(s):  
Angle Of Attack ◽  
Water Velocity ◽  
The Body ◽  
Bladder Volume ◽  
Water Current ◽  
Acclimation Temperature ◽  
Small Fish ◽  
Swim Bladder ◽  
Semotilus Atromaculatus ◽  
Creek Chub

Creek chub (Semotilus atromaculatus) reduce buoyancy by decreasing swim-bladder volume when exposed to water current. Fish were near neutral buoyancy (0.956–0.997 mL∙g−1) in still water but in current small fish (< 73 mm) were more buoyant (0.668 mL∙g−1) than larger fish (0.540 mL∙g−1). Extent of buoyancy alteration was influenced by acclimation temperature, water velocity, and an interaction of both these factors. Reduction of buoyancy on exposure to water current required 3–6 h and the rate of decrease (0.035–0.068 mL∙g−1∙h−1) was independent of acclimation temperature and water velocity. The hypothesis that creek chub reduce buoyancy when exposed to water current to compensate for the lift created due to deflection of water over the dorsal surface of the body was supported by the following findings. When initially exposed to current, fish lowered the head assuming an angle of attack of 9–12° from horizontal. A horizontal (< 1°) angle of attack was gradually assumed during buoyancy adjustment. Fish acclimated to moderate current for 12 or 24 h tired less readily in strong current (80% took 43 and 44 min, respectively) than those not acclimated or acclimated for 6 h (80% took 33 and 25 min, respectively). Fish induced to swim in still water reduced buoyancy to a similar extent as those in current. Key words: swim-bladder volume change, temperature, hydrodynamic lift, swimming angle of attack, time to fatigue

Assessing the effects of positive buoyancy on rainbow trout (Oncorhynchus mykiss) held in gas supersaturated water

1990 ◽  
Vol 68 (5) ◽  
pp. 969-973 ◽  
Author(s):  
J. M. Shrimpton ◽  
D. J. Randall ◽  
L. E. Fidler
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Ambient Pressure ◽  
Large Change ◽  
Bladder Volume ◽  
Bladder Pressure ◽  
Small Fish ◽  
Swim Bladder ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
The Impact

We examined the effects of swim bladder overinflation associated with dissolved gas supersaturation on rainbow trout (Oncorhynchus mykiss). The change in swim bladder volume with increased swim bladder pressure was measured in fish subjected to a decrease in ambient pressure. An expansion of swim bladder volume occurs that is related to the excess swim bladder pressure. The volume change results in a decrease in density and positive buoyancy in the fish. Small fish are adversely affected when exposed to gas supersaturated water because of the high swim bladder pressure required to force gas out the pneumatic duct. Changes in behaviour and depth distribution of fish held in gas supersaturated water were measured in a 2 m deep observation column. A large change in density caused small fish to increase depth and compensate for the swim bladder expansion. Although swim bladder inflation occurs for all sizes of trout held in gas supersaturated water, the impact is greatest for small fish and they must compensate by seeking depth. However, adequate depth to compensate for positive buoyancy may not always exist. In such a case, fish must swim continuously in a head down position to overcome excess buoyancy. The power necessary for a fish to swim with an overinflated swim bladder is greatest for small fish that show the largest change in density.

Buoyancy and aerial respiration: factors influencing the evolution of reduced swim-bladder volume of some Central American catfishes (Trichomycteridae, Callichthyidae, Loricariidae, Astroblepidae)

1976 ◽  
Vol 54 (7) ◽  
pp. 1030-1037 ◽  
Author(s):  
John H. Gee
Keyword(s):  
Body Weight ◽  
The Body ◽  
Central American ◽  
Bladder Volume ◽  
Swim Bladder ◽  
Partial Pressure Of Oxygen ◽  
Respiratory Organ ◽  
Aerial Respiration ◽  
Mode Of Life ◽  
Hypoxic Water

Swim-bladder volume of nine species of Central American catfishes from four families was measured and found to be very small. In seven species it supported less than 5% of the body weight in water. Seven of the nine species were found to breathe air and the volume of gas in the accessory respiratory organ varied between species, supporting from less than 5% to more than 80% of the body weight in water. In only one of these species was there gas in the accessory respiratory organ in both normoxic and hypoxic water and only in this species did the organ have a definite hydrostatic function. The remaining air-breathing species used aerial respiration only in hypoxic water and there were differences between species in frequency of gulping for air and in partial pressure of oxygen in the water at which gulping was initiated. The evolution of a reduced swim-bladder volume appears to have been in response to a demersal mode of life.

Role of water current and related variables in determining buoyancy in the sticklebacks Culaea inconstans and Pungitius pungitius

1988 ◽  
Vol 66 (9) ◽  
pp. 2006-2014 ◽  
Author(s):  
Barbara J. Beaver ◽  
John H. Gee
Keyword(s):  
Inverse Relationship ◽  
Water Velocity ◽  
Water Current ◽  
Swim Bladder ◽  
Pungitius Pungitius ◽  
Weak Current ◽  
Low Velocity ◽  
Culaea Inconstans ◽  
Time Required

The sticklebacks Culaea inconstans and Pungitius pungitius alter buoyancy (lift from the swim bladder) in the field primarily in response to changes in water velocity. Potential adjustment is extensive and is only realized when fish are exposed to current for several days. Buoyancy measured on fish from the field showed an inverse relationship with water velocity and temperature. Buoyancy was also highest in fish living among vegetation. However, vegetation was restricted to still water or areas of very low velocity. In the laboratory, water temperature affected buoyancy of C. inconstans in current only; there, at 6 °C, buoyancy was greater than at higher temperatures. In the field an unknown factor(s), dependent on temperature, affects buoyancy. An inverse relationship was found between buoyancy and water velocity in the laboratory, and adjustment of buoyancy was slow. The time required for buoyancy to decrease from maximum to minimum levels was 4 and 7 d for P. pungitius and C. inconstans, respectively. In the field, minimum buoyancy levels were not reached because fish were exposed to weak current velocities for short intervals. The ability to reduce swim bladder lift (volume) in strong velocities and replace it with hydrodynamic lift and vice versa is seen as an adaptation to environments where water velocity varies in time and space permitting fishes to use the most effective source of lift.

Trichodina algonquinensis, a new species of peritrich ciliate from Ontario freshwater fish, and observations on its transmission

1983 ◽  
Vol 61 (5) ◽  
pp. 1159-1164 ◽  
Author(s):  
Lianxiang Li ◽  
Sherwin S. Desser
Keyword(s):  
Perca Flavescens ◽  
Lateral View ◽  
The Body ◽  
Semotilus Atromaculatus ◽  
Mean Diameter ◽  
The Common ◽  
The Mean ◽  
Golden Shiners ◽  
Creek Chub ◽  
A New Species

Trichodina algonquinensis n. sp. is described from the urinary bladder and ureters of the perch (Perca flavescens) and the common shiner (Notropis cornutus) from Lake Sasajewun, Algonquin Park, Ontario. The ciliate is hat shaped, flattened, and ellipsoidal in lateral view. The mean diameter of the oral portion of the body is 88.4 μm (58.5–123.5 μm; n = 21) and of the adhesive disc, 54.9 μm (42.9–57.2 μm; n = 30). It has 38 (35–42; n = 17) denticles, a horseshoe-shaped macronucleus, a round to ovoid micronucleus situated near the end of one arm of the macronucleus, and the oral groove spiral is 540°. Experiments indicate that in aquaria the ciliate is readily transmitted from perch to common shiners and golden shiners (Notemigonus crysoleucas) but not to creek chub (Semotilus atromaculatus).

Mechanisms responsible for the niche shift of brook charr, Salvelinus fontinalis Mitchill, when living sympatrically with creek chub, Semotilus atromaculatus Mitchill

1984 ◽  
Vol 62 (8) ◽  
pp. 1548-1555 ◽  
Author(s):  
Pierre Magnan ◽  
Gérard J. FitzGerald
Keyword(s):  
Laboratory Experiments ◽  
Salvelinus Fontinalis ◽  
Niche Shift ◽  
Intraspecific Aggression ◽  
Brook Charr ◽  
Semotilus Atromaculatus ◽  
High Level ◽  
Gill Raker ◽  
Creek Chub ◽  
Study Laboratory

When brook charr, Salvelinus fontinalis Mitchill, are in allopatry in oligotrophic Québec lakes, they feed largely on macrobenthic invertebrates. However, when brook charr cooccur with creek chub, Semotilus atromaculatus Mitchill, they feed largely on zooplankton. In the present study, laboratory experiments showed that creek chub were more effective than brook charr in searching for hidden, patchily distributed prey. The searching efficiency of an individual chub feeding in a group was improved through social facilitation. In contrast, the high level of intraspecific aggression observed in brook charr prevents the formation of such feeding groups. In the laboratory, brook charr were able to displace creek chub from the food source because of interspecific aggression. Data are presented showing that chub are morphologically better adapted than charr to feed on benthos (subterminal orientation of the mouth and protrusible premaxillae), while the charr are better adapted than chub to feed on zooplankton (gill raker structure). Differences in feeding behaviour, morphology, and relative abundance between these species appear to be important in the observed niche shift of brook charr in nature.

Improvement of Torque Performance of a Vertical Axis Type Marine Turbine for a Water Current Generation System

2010 ◽  
Author(s):  
Tomoki Ikoma ◽  
Shintaro Fujio ◽  
Koichi Masuda ◽  
Chang-Kyu Rheem ◽  
Hisaaki Maeda
Keyword(s):  
Turbine Blades ◽  
Angle Of Attack ◽  
Cross Flow ◽  
Vertical Axis ◽  
Hydrodynamic Forces ◽  
Water Current ◽  
Current Channel ◽  
Marine Current ◽  
Water Turbine ◽  
Type Water

This paper describes the possibility of an improvement of torque performance and hydrodynamic forces on a vertical axis type water turbine, used for marine current generating system. The water turbine analyzed here is based on a Darrieus turbine with vertical blades. We considered possibilities of controlling the angle of attack of blades in order to improve the starting performance and to reduce energy loss during the rotation of the turbine. We used blade-element/ momentum theory in order to investigate the variations appearing in torque performance when the angle of attack were controlled. We also proved the validity of our predictions of hydrodynamic forces on the blade and the turbine, made through CFD calculation, by comparing them with the results of corresponding model tests in a current channel. In the corresponding model test we investigated not only the hydrodynamic forces on the turbine with three fixed blades, but also the inline force and the cross-flow force on the rotating turbine with three blades. Regarding the cyclic pitching of turbine blades, results suggest that significant increase in average turbine torque is possible.

scholarly journals Parasitic Lesions in Fish in the Federal District, Brazil

2021 ◽  
Vol 49 ◽  
Author(s):  
Jair Alves Ferreira Junior ◽  
Saulo Pereira Cardoso ◽  
Nathália Dela-Sávia Da Fonseca ◽  
Karla Alvarenga Nascimento ◽  
Fábio Rodrigues ◽  
...  
Keyword(s):  
Water Quality ◽  
Federal District ◽  
Laboratory Diagnosis ◽  
Skin Lesions ◽  
Climatic Conditions ◽  
The Body ◽  
Nutritional Deficiencies ◽  
Small Fish ◽  
Cell Degeneration ◽  
Pathology Laboratory

Background: Brazil has a vast territory and favorable climatic conditions that allow the cultivation of freshwater fish. The intensification of the productive system can cause an imbalance in the aquatic environment as a result of poor water quality, nutritional deficiencies and infectious or parasitic diseases. The laboratory diagnosis and the determination of the prevalence of the main lesions, which occur in a certain region, help to guide towards the etiological diagnosis. This study aimed to describe the main parasitic lesions in fish in the routine at the Veterinary Pathology Laboratory of the Universidade de Brasília. Material, Methods & Results: All records of fish with parasitic lesions were recovered. Those cases in which there was an intralesional parasite and which presented lesions compatible with the parasite were included. The screening of ectoparasites was done by scraping the superficial mucus from the gills and skin. Organ sections were routinely processed for histopathologyand stained with hematoxylin-eosin (HE). In some records, parasitological identification was carried. The information was divided into the species of the affected fish, epidemiology of the outbreak (water quality, temperature, type of breeding), lesion distribution, etiology and macroscopic and microscopic changes. The resulting data was organized in absolute frequency and percentage. In this study, 22 cases were counted, between individual deaths and outbreaks, totaling 83 necropsied teleost fish.Inflammatory changes of parasitic origin were seen in 13/22 (59%) of the cases had lesions of parasitic origin. Skin lesions and gills were the most relevant. Macroscopically, red areas or spots of hyperemia or hemorrhage on the body surface were the most prevalent findings. Under microscopy, proliferative gill inflammation was the most relevant diagnosis. Pscinoodinium pilullare (Dinoflagellida), Ichthyophthirius multifiliis (Ciliophora), and monogenetic worms (Monogenea) were the main parasites found. Trichodina sp. (Ciliophora), Ichtyobodo sp. (Kinetoplastida), Amoebas, and Chilodonella sp. (Ciliophora), were seen in fewer numbers. An unusual case suggestive of parasitism by Eustrongylides sp. (Nematoda), in a pirá-brasília (Simpsonichthys boitonei), specimen has been recorded.Discussion: The diagnoses were based on epidemiology, anatomopathological and parasitological findings. The most frequent and significantly lethal lesion in the study was proliferative and / or hyperplastic branchitis. Proliferative branchitis with lamellar epithelial hyperplasia (LEH) is a response to some type of chemical or mechanical injury to the gill epithelium in order to protect the capillaries from further damage or microbial penetration. However, it also increases the diffusion distance between capillaries and the environment and, therefore, hinders breathing, excretory and osmoregulatory functions. Protozoan infections and monogenetic worms in general generated LEH and skin lesions of mechanical origin. Secondary bacterial infection, were observed in this parasitosis determining the cause of death of the fish. Its pathogenicity comes from the lesions caused by the colonization and histophagy of the epithelial surfaces, mainly gills and skin, causing epithelial proliferation, lamellar cell fusion, epithelial cell degeneration and necrosis forming several ulcers in the epithelium after the release of mature trophies. The pathogenesis of parasitism by Eustrongylides spp. is considerable when there is a large quantity of these larvae that can cause intestinal obstruction, rupture and compression of viscera, of greater importance in small fish. The main parasites of necropsied fish were protozoa and monogenetic worms, which mainly cause branquitis and dermatitis in varying grades.

Energetic cost of active branchial ventilation in the sharksucker, Echeneis naucrates

1983 ◽  
Vol 103 (1) ◽  
pp. 185-192 ◽  
Author(s):  
J. F. Steffensen ◽  
J. P. Lomholt
Keyword(s):  
Oxygen Consumption ◽  
Water Velocity ◽  
Moving Object ◽  
Water Current ◽  
Energetic Cost ◽  
Gill Ventilation

1. Sharksuckers use active branchial ventilation when swimming or at rest in stationary water. When attached to a moving object or when placed in a water current, they shift to ram gill ventilation as water velocity exceeds a certain threshold. 2. Water velocities required for the transition from active to ram gill ventilation were from 10–50 cm s-1, depending on the size of the fish. 3. Oxygen consumption increased between 3.7 and 5.7% when the fish shifted from ram gill ventilation to active branchial pumping. 4. When water velocity was increased beyond the threshold for ram gill ventilation, no further increase in oxygen consumption was observed. 5. It is concluded that the energetic cost of active ventilation in sharksuckers is lower than has previously been reported for fish in general.

Pectoral fin locomotion in the striped surfperch. I. Kinematic effects of swimming speed and body size

1996 ◽  
Vol 199 (10) ◽  
pp. 2235-2242 ◽  
Author(s):  
E Drucker ◽  
J Jensen
Keyword(s):  
Body Size ◽  
Swimming Speed ◽  
Beat Frequency ◽  
Limited Range ◽  
The Body ◽  
Small Fish ◽  
Large Fish ◽  
Pectoral Fin ◽  
Transition Speed ◽  
Speed Up

Swimming trials at increasing velocity were used to determine the effects of steady swimming speed on pectoral fin kinematics for an ontogenetic series of striped surfperch Embiotoca lateralis, ranging from 6 to 23 cm in standard length (SL). The fin stroke cycle consisted of a propulsive period, the duration of fin abduction and adduction, and a 'refractory' period, during which the fin remained adducted against the body. Pectoral fin-beat frequency (fp) measured as the inverse of the entire stride period, as in past studies, increased curvilinearly with speed. Frequency, calculated as the reciprocal of the propulsive period alone, increased linearly with speed, as shown previously for tail-beat frequency of fishes employing axial undulation. Fin-beat amplitude, measured as the vertical excursion of the pectoral fin tip during abduction, increased over a limited range of low speeds before reaching a plateau at 0.35&shy;0.40 SL. Pectoral fin locomotion was supplemented by intermittent caudal fin undulation as swimming speed increased. At the pectoral&shy;caudal gait transition speed (Up-c), frequency and amplitude attained maxima, suggesting that the fin musculature reached a physiological limit. The effects of body size on swimming kinematics differed according to the method used for expressing speed. At a given absolute speed, small fish used higher stride frequencies and increased frequency at a faster rate than large fish. In contrast, the relationship between fp and length-specific speed (SL s-1) had a greater slope for large fish and crossed that for small fish at high speeds. We recommend that comparisons across size be made using speeds expressed as a percentage of Up-c, at which kinematic variables influencing thrust are size-independent.

Sign in / Sign up

Export Citation Format

Share Document