The Reaction of Fish to Moving Backgrounds

1963 ◽  
Vol 40 (3) ◽  
pp. 437-446
Author(s):  
F. R. HARDEN JONES
Keyword(s):  
Marine Species ◽  
The Other ◽  
Water Current ◽  
Fish Migration ◽  
Freshwater Species ◽  
Water Currents

1. An apparatus is described to study the response of fish to moving backgrounds. 2. Observations were made on pike, three-spined sticklebacks, trout, perch and roach; cod, whiting, whiting-pout, smelt, herring, armed bullhead, lesser weaver, plaice, dabs, soles and dogfish. 3. Pike followed a moving background equivalent to a water current of 0.03 cm./sec. Pike were the best and most consistent performers among the freshwater species, followed by the three-spined stickleback, trout, roach and perch. 4. The marine species fell into two groups. The cod, whiting, whiting-pout, smelt, and herring responded to background movements equivalent to water currents of 1-2 cm./sec. The other fish failed to respond to movements equivalent to currents up to 24 cm./sec. and it is thought that this may have been due to contact with the bottom. 5. The fish that orientated to a moving background also responded kinetically. Cod, whiting, and whiting-pout gained on the background (swam upstream) at rotational speeds equivalent to water currents less than 1 fish lengthlsec., but started to lag behind at speeds equivalent to currents faster than 1-2 L/sec., although the fish were shown to be capable of swimming fast enough to keep pace with the background. Herring gained on the background up to rotational speeds equivalent to water currents of 3-4 fish lengths/sec. 6. The results are discussed in relation to the contranatant theory of fish migration.

Swimbladder Function and Buoyancy Regulation in the Killifish Fundulus Heterochtus

1992 ◽  
Vol 166 (1) ◽  
pp. 61-81
Author(s):  
EDWARD M. GOOLISH
Keyword(s):  
Body Weight ◽  
Center Of Gravity ◽  
Water Current ◽  
Control Fish ◽  
Vertical Position ◽  
Vertical Force ◽  
Water Currents ◽  
Pectoral Fins ◽  
Artificial Lift ◽  
Rate Of Increase

Killifish, Fundulus heteroclitus, subjected to artificial lift above their center of gravity (10% of body weight) required a minimum of 7–8 days to resorb swimbladder gases completely. The swimbladders of some fish, however, did not fall below 50% of normal volume. The rate of increase in swimbladder volume upon removal of lift varied little among individuals, with approximately 6 days required for complete refilling. Previous deflation of the swimbladder (by syringe) did not result in faster or more complete gas resorption when the fish were subjected to artificial lift. This suggests that the constraint to resorption observed in some fish is not mechanical, e.g. connective tissue, but may reflect individual variability in perception of the stimulus. Swimbladder dry mass, which scaled as (body mass)0.79, was not affected by exposure to artificial lift. However, fish subjected to 7–11 days of artificial lift displayed slower rates of gas secretion upon removal of lift than control fish whose swimbladders had been evacuated by syringe. The initial rate was 65 % of that of control fish, with two additional days required to achieve normal buoyancy. Also, the rate of swimbladder gas resorption was 24 % faster the second time fish were exposed to artificial lift. These results demonstrate that the capacity for gas secretion and resorption can be altered by previous exposure to hydrostatic challenges. Killifish buoyancy, expressed as swimbladder volume per weight of the gas-free fish in water, fell from 0.95 to 0.70 mlg−1 after 5 days of exposure to water current. Removal of the pectoral fins eliminated 70% of this decrease, while removal of the pelvic fins had no effect. The rate of gas resorption by fish subjected to artificial lift was also not affected by removal of the pectoral fins. From these results it appears that the decrease in swimbladder volume in fish exposed to water currents is a consequence of lift forces produced by the pectoral fins, but that they are not required for regulation. Fish exposed to water currents or artificial lift swim with a head-down angle of attack. Theoretical estimates show that the vertical force component generated by this swimming behavior is of the appropriate magnitude to compensate for the additional lift. Fish confined in transparent cages near the surface of the water were less buoyant (0.91 mlg−1) than fish similarly maintained at the bottom of the tank (0.98mlg−1). However, because this effect was small, 10% of swimbladder volume, visual perception of vertical position is apparently not the primary stimulus for volume regulation. Partial lift (2.65 % of body weight) resulted in the resorption of twice as much swimbladder gas when attachment was anterior to the fish's center of gravity than when it was an equal distance posterior to the center of gravity. When equal amounts of partial lift and weight were added, lift anterior and weight posterior, no change in swimbladder volume occurred. With the position of these forces reversed, swimbladder volume increased by 31 % to 1.27 ml g−1. These results suggest that fish respond to pitching forces, i.e. longitudinal lift moments, as a stimulus for swimbladder gas secretion and resorption.

EFFECT OF WATER CURRENT ON UNDERWATER GLIDER VELOCITY AND RANGE

2016 ◽  
Vol 78 (10-4) ◽  
Author(s):  
Muhammad Yasar Javaid ◽  
Mark Ovinis ◽  
Fakhruldin Mohd Hashim ◽  
Adi Maimun ◽  
Yasser M. Ahmed ◽  
...  
Keyword(s):  
Steady State ◽  
Numerical Simulations ◽  
Relative Motion ◽  
Water Current ◽  
Underwater Glider ◽  
Water Currents ◽  
Effect Of Water ◽  
Actuation System ◽  
Autonomous Underwater Glider

An autonomous underwater glider speed and range is influenced by water currents. This is compounded by a weak actuation system for controlling its movement. In this work, the effects of water currents on the speed and range of an underwater glider at steady state glide conditions are investigated. Extensive numerical simulations have been performed to determine the speed and range of a glider with and without water current at different net buoyancies. The results show that the effect of water current on the glider speed and range depends on the current relative motion and direction. In the presence of water current, for a given glide angle, glide speed can be increased by increasing the net buoyancy of the glider.

scholarly journals Contrasting Toxin Selectivity between the Marine Pufferfish Takifugu pardalis and the Freshwater Pufferfish Pao suvattii

Toxins ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 470 ◽  
Author(s):  
Wei Gao ◽  
Yoko Kanahara ◽  
Misako Yamada ◽  
Ryohei Tatsuno ◽  
Hiroyuki Yoshikawa ◽  
...  
Keyword(s):  
Marine Species ◽  
The Body ◽  
Freshwater Species ◽  
Oral Gavage ◽  
Paralytic Shellfish Poison ◽  
Toxin Content ◽  
Paralytic Shellfish ◽  
Strong Contrast

To clarify the differences in toxin selectivity between marine and freshwater pufferfish, we conducted experiments in artificially reared nontoxic specimens of Takifugu pardalis (marine) and Pao suvattii (freshwater) using tetrodotoxin (TTX) and paralytic shellfish poison (PSP; decarbamoylsaxitoxin (dcSTX) or saxitoxin (STX)). T. pardalis specimens were administered feed homogenate containing TTX or dcSTX (dose of toxin, 55.2 nmol/fish) and P. suvattii specimens were administered feed homogenate containing TTX + STX (dose of each toxin, 19.2 nmol/fish) by oral gavage. The toxin content in the intestine, muscle, skin, liver, and gonads was quantified after 24 and 48 or 72 h. In T. pardalis, TTX administered into the intestine was absorbed into the body and transferred and retained mainly in the skin and liver, while dcSTX was hardly retained in the body, although it partly remained in the intestine. In strong contrast, in P. suvattii, little TTX remained in the body, whereas STX was absorbed into the body and was transferred and retained in the ovary and skin. The findings revealed that TTX/PSP selectivity differs between the marine species T. pardalis and the freshwater species P. suvattii. T. pardalis, which naturally harbors TTX, selectively accumulates TTX, and P. suvattii, which naturally harbors PSP, selectively accumulates PSP.

scholarly journals Two New Hyporheic Amphipods, Bogidiella ( Bogidiella) Cyrnensis n. sp. and Bogidiella (Medigidiella?) Paolii n. sp., from Corsica

1983 ◽  
Vol 53 (1) ◽  
pp. 82-92 ◽  
Author(s):  
F. Hovenkamp ◽  
W. Hovenkamp ◽  
J.J. van der Heide
Keyword(s):  
New Species ◽  
Marine Species ◽  
Small Rivers ◽  
Amphipod Species ◽  
Freshwater Species ◽  
The Family ◽  
The Mediterranean

Two new amphipod species of the family Bogidiellidae were found in the hyporheal of two small rivers on Corsica. Both new species, Bogidiella (Bogidiella) cyrnensis n. sp. and B. paolii n. sp. (provisionally placed in the subgenus Medigidiella, but a definitive classification will have to wait till males are found), encountered at altitudes of 135 m and 750 m, respectively, show more affinities with certain freshwater species of Sardinia than with marine species of the Mediterranean.

scholarly journals Fish communities of the Wilderness Lakes System in the southern Cape, South Africa

Koedoe ◽  
2016 ◽  
Vol 58 (1) ◽  
Author(s):  
Alexis A. Olds ◽  
Nicola C. James ◽  
M. Kyle S. Smith ◽  
Olaf L.F. Weyl
Keyword(s):  
South Africa ◽  
Key Management ◽  
Mouth Opening ◽  
Marine Species ◽  
Freshwater Species ◽  
Sediment Removal ◽  
Management Actions ◽  
System A ◽  
Artificial Mouth ◽  
Estuarine Resident

The Wilderness Lakes System, a temporarily open and closed estuary with three associated lakes situated in the southern Cape region of South Africa, was sampled using a range of sampling gears to assess the fish community. A total of 25 species were sampled throughout the system, with the highest diversity in the Touw Estuary (23 species) and the lowest in Langvlei (11 species). Estuary-associated marine species (13 species) dominated species richness with smaller proportions of estuarine resident (7 species), freshwater (3 species) and catadromous species (2 species). Estuarine resident species dominated the catch numerically. The size–class distribution of euryhaline marine species indicated that upon entering the Touw Estuary as juveniles, the fish move up the system towards Rondevlei where they appear to remain. Three freshwater species were recorded in the system, all of which are alien to the Wilderness Lakes System. Decreasing salinity in the upper lakes appears to be a driving factor in the distribution and increasing abundance of the freshwater fishes. Sampling followed a drought, with the system experiencing substantially increased levels of mouth closure compared to a similar study conducted in the 1980s. The timing of mouth opening and the degree of connectivity between the lakes influence the nursery function of the system as a whole. Management actions need to focus on improving ecological functioning of this system, in particular how mouth opening is managed, to facilitate nursery function and limit the establishment of invasive species.Conservation implications: Key management actions are required to improve fish recruitment potential into and within the system. These include maintenance of adequate marine inflow through adherence to artificial mouth breaching protocols and improving connectivity between the lakes through sediment removal from localised deposition points within the connecting channels.

scholarly journals Dead Reckoning for Trajectory Estimation of Underwater Drifters under Water Currents †

2020 ◽  
Vol 8 (3) ◽  
pp. 205 ◽  
Author(s):  
Itzik Klein ◽  
Roee Diamant
Keyword(s):  
Dead Reckoning ◽  
Water Current ◽  
Body Frame ◽  
Trajectory Estimation ◽  
Water Currents ◽  
Heading Direction ◽  
External Position ◽  
Moving Direction ◽  
Short Time ◽  
Physical Phenomena

Between external position updates, the most useful technique for trajectory estimation of a submerged drifter is dead reckoning (DR). These devices drift with the water current to measure the current’s velocity or to observe physical phenomena. We focus on the specific but important case of when the drifter, due to its size and shape, experiences acceleration by the water current, an effect that must be taken into account during the DR. The force induced by the water current over the drifter is translated into a shift in the heading direction, thus creating a horizontal (sideslip) and a vertical (angle of attack) directional angles between the drifter’s moving direction and its body frame. In this paper, we extend and modify techniques used for pedestrian DR and propose PCA-DR: a principle component analysis-based DR algorithm to estimate the directional angles. Used for cases where the water current is significant such that its force induces acceleration over the drifter and used only for short time periods of a few seconds between navigation fixes, PCA-DR uses acceleration measurements only and does not assume knowledge of the drifter’s dynamics. Instead, as part of the DR process, PCA-DR estimates the directional angles induced by the water current. Compared to the traditional DR approach, our results demonstrate good navigation performance. A designated sea experiment demonstrates the applicability of PCA-DR in a realistic sea environment.

Biomass transport to and from an upper estuarine area by migration of juvenile Atlantic herring Clupea harengus

2000 ◽  
Vol 57 (7) ◽  
pp. 1404-1409 ◽  
Author(s):  
Joachim Maes ◽  
Frans Ollevier
Keyword(s):  
Marine Species ◽  
Growth Conditions ◽  
Clupea Harengus ◽  
Fish Migration ◽  
Atlantic Herring ◽  
Seaward Migration ◽  
Fish Migrations ◽  
The Difference ◽  
European Estuaries

A model describing fish abundance resulting from fish migration and mortality in an upper estuary is presented. This model can be used to estimate biomass transports by fish migrations between estuary and sea and to assess production assimilated in the estuary. It was applied to herring Clupea harengus L., a marine species with 0+ juveniles that migrate during winter to temperate European estuaries. It was shown that different mortality regimes greatly affected the number of fish that eventually emigrated and, hence, the biomass that was exported during the seaward migration. The difference between imported and exported biomass was assessed under different growth conditions and varied from positive to negative as mortality rates increased. The discrepancy between export of biomass and in situ produced biomass showed that fish production was not necessarily transported to the sea when emigrating. It was tentatively concluded that export of biomass out of the estuary only occurs if populations move seaward before winter.

Functional Morphology of the Mouthparts and Gastric Mill in the Hermit Crabs Clibanarius taeniatus (Milne Edwards), Clibanarius virescens (Krauss), Paguristes squamosus McCulloch and Dardanus setifer (Milne-Edwards) (Anomura: Paguridae)

1979 ◽  
Vol 30 (5) ◽  
pp. 683 ◽  
Author(s):  
J Kunze ◽  
DT Anderson
Keyword(s):  
The Other ◽  
Hermit Crabs ◽  
Water Current ◽  
Gastric Mill ◽  
Filter Feeding ◽  
Food Material ◽  
Cardiac Stomach ◽  
The Third ◽  
General Arrangement ◽  
Feeding Specialization

The structure of the maxillipeds and mouthparts is generally similar in C. taeniatus, C. virescens, P. squamosus and D. setifer, but differences exist in the setation of these limbs and in the form of the crista dentata of the third maxilliped endopods. The differences in setation are not sharply defined and are not indicative of different feeding processes. The crista dentata are weakly developed in C. taeniatus and C. virescens, strongly developed in P. squamosus and D. setifer, reflecting dietary differences. C. taeniatus is a soft food detritivore, using the chelipeds and third maxillipeds to scoop up food. C. virescens is detritivorous and macrophagous, using the chelae and the crista dentata for triturition. P. squamosus is mainly macrophagous, employing similar methods. D. setifer is macrophagous and predatory, using the chelae to grasp and break up its food and the crista dentata for food transfer. Sorting and ingestion of the food material by the maxillipeds and mouthparts occurs in a similar manner in all species. P. squamosus also filters particulate food from a water current produced by a unilateral action of the exopods of the second and third maxillipeds. Particles filtered from the current by the antennules, antennae, maxilliped exopods, chelipeds and pereiopods are cleaned off by the endopods of the third maxillipeds and passed to the inner mouthparts. No evidence was obtained of filter feeding in the other three species investigated. The structure of the proventriculus, including the detailed arrangement of the ossicles and the general arrangement of the musculature, is similar in C. taeniatus to that described by Meiss and Norman in Pagurus pollicaris. A similar proventriculus structure obtains in C. virescens, P. squamosus and D. setifer as a distinctive feature of pagurids. The gastric mill has a common grinding action in all species, but the development and denticulation of the lateral accessory teeth, lateral teeth, dorsal tooth and cardiopyloric valve are positively correlated with the degree of macrophagy. The filtratory system leading via the ampullae to the digestive glands, in contrast, is generally similar in the four species, irrespective offood type, indicating that the usable part of the food is reduced to a similar consistency in all species before it leaves the cardiac stomach. Present knowledge of feeding mechanisms in pagurids is reviewed. The basic adaptation in this group is to a generalized omnivorous mode of feeding on benthic, particulate, detrital and moderately macroscopic material, variously displayed in different species. Two major trends in feeding specialization have arisen from this. One is macrophagy and predation on large food masses. The other is filter feeding, using either specialized antennae or a number of anterior limbs. All modes of filter feeding in pagurids appear to be modifications of basic cleaning processes involving the endopods of the third maxillipeds. Each of the two specializations, macrophagy and filter feeding, has evolved several times independently within the Paguridae.

scholarly journals Spatial scales of interannual recruitment variations of marine, anadromous, and freshwater fish

1997 ◽  
Vol 54 (6) ◽  
pp. 1400-1407 ◽  
Author(s):  
R A Myers ◽  
G Mertz ◽  
J Bridson
Keyword(s):  
Spatial Scale ◽  
Freshwater Fish ◽  
Marine Environment ◽  
Environmental Variables ◽  
Large Scale ◽  
Spatial Scales ◽  
Marine Species ◽  
Freshwater Species ◽  
Environmental Agents

We examine the spatial scale of variability in recruitment for 11 marine, three anadromous, and five freshwater species. Generally the spatial scale of recruitment correlations for marine species is approximately 500 km, compared with less than 50 km for freshwater; anadromous species fall between these two scales. The scale for marine species is comparable with (but less than) that of the largest-scale environmental variables (and is compatible with the idea that large-scale environmental agents influence recruitment). Our results are consistent with the hypothesis that predation is a more important factor in determining recruitment in freshwater than it is in the marine environment.

Effect of unidirectional water currents on displacement behaviour of the green sea urchin Strongylocentrous droebachiensis

2013 ◽  
Vol 93 (7) ◽  
pp. 1923-1928 ◽  
Author(s):  
Bryan L. Morse ◽  
Heather L. Hunt
Keyword(s):  
Sea Urchin ◽  
Sea Urchins ◽  
Flow Speed ◽  
Strongylocentrotus Droebachiensis ◽  
Movement Speed ◽  
Water Current ◽  
Flume Experiments ◽  
Water Currents ◽  
Green Sea Urchin ◽  
The Impact

Sea urchins can have important ecological effects on benthic communities through their aggregation and feeding behaviour. Urchin movement has been demonstrated to be negatively affected by wave action, but the impact of unidirectional tidal currents on urchin movement has not been investigated. This study examines the effect of unidirectional water velocity on the direction of displacement and movement rate of the green sea urchin, Strongylocentrotus droebachiensis. In laboratory flume experiments there was a clear effect of water currents on the displacement of sea urchins. At speeds ≤30 cm s−1 urchins moved across the current in a downstream direction, but at speeds of ≥36 cm s−1 the urchins switched directions by more than 90° and moved across the current in an upstream direction. There was a significant effect of flow speed on urchin movement speed, with urchin movement speed decreasing as water current speed increased.

Sign in / Sign up

Export Citation Format

Share Document