Patterns of Aggressive Attack in Juvenile Steelhead Trout (Salmo gairdneri)

1985 ◽  
Vol 42 (11) ◽  
pp. 1702-1706 ◽  
Author(s):  
Jeremy C. Abbott ◽  
Lawrence M. Dill
Keyword(s):  
Central Body ◽  
The Body ◽  
Salmo Gairdneri ◽  
Steelhead Trout ◽  
Caudal Fin ◽  
Dorsal Fin ◽  
Body Patterns ◽  
Aggressive Attack ◽  
Juvenile Trout ◽  
Body Section

Nipping is a potentially damaging aggressive behavior of juvenile steelhead trout (Salmo gairdneri). By analyzing videotaped interactions of pairs of fish we determined where nips were aimed and where they contacted the opponent's body. Patterns of fin damage were also assessed. Aims and nips (contacts) were distributed differently in reciprocal and nonreciprocal aggressive bouts. In nonreciprocal bouts, aims were directed mainly at the dorsal fin, central body section, and caudal fin. Nip contact was biased towards the caudal fin. In reciprocal bouts, both aims and nips were concentrated on the dorsal fin and anterior portions of the body. We suggest that juvenile steelhead adjust their fighting tactics in response to opponent behavior. Mouth fighting, a novel behavior in juvenile trout, was observed in some reciprocal bouts. The dorsal fin incurred the greatest damage. We conclude that aggression (nipping) is responsible for the dorsal fin damage commonly observed in hatchery-reared salmonids.

II.—New Palæoniscidæ from the English Coal-Measures

1888 ◽  
Vol 5 (6) ◽  
pp. 251-254 ◽  
Author(s):  
R. H. Traquair
Keyword(s):  
The Body ◽  
The Other ◽  
Caudal Fin ◽  
Dorsal Fin ◽  
Coal Measures

Of this I have seen only two specimens. One of them, slightly longer than the other, measures 3½ inches in length up to the commencement of the caudal fin, which is deficient in both; the greatest depth of the body ½½ inch, the length of the head nearly the same. The dorsal fin is opposite the interval between the ventral and the anal; both dorsal and anal are triangular acuminate in shape, with delicate rays which at first are somewhat distantly articulated, the joints being ornamented with one or two longitudinal sulci. The pectorals are not seen in either specimen, but the smaller of the two shows a well-preserved ventral, which is pretty large, and acuminate in shape.

Pelvicachromis signatus and Pelvicachromis rubrolabiatus, two new cichlid species (Teleostei, Perciformes) from Guinea, West Africa

Zootaxa ◽  
2004 ◽  
Vol 454 (1) ◽  
pp. 1 ◽  
Author(s):  
ANTON LAMBOJ
Keyword(s):  
West Africa ◽  
Black Spot ◽  
Color Pattern ◽  
The Body ◽  
Caudal Peduncle ◽  
Caudal Fin ◽  
Cichlid Species ◽  
Dorsal Fin ◽  
Black Spots ◽  
Vertical Bars

Pelvicachromis rubrolabiatus and P. signatus are described from Guinea. They differ from other members of Pelvicachromis, except P. humilis, in having two contiguous tubular infraorbital ossicles instead of three with a gap between the 2 nd and 3 rd and in displaying a color pattern of seven to eight dark vertical bars during certain behavioral situations. Pelvicachromis rubrolabiatus differs from P. humilis and P. signatus in having seven instead of eight vertical bars on the body and from P. signatus in having a lesser preorbital depth. Pelvicachromis signatus differs from P. humilis in the presence of characteristic black markings in the dorsal and caudal fin of males, a black spot on the caudal peduncle of females and occasionally one or two black spots in the female s dorsal fin.

Locomotor function of the dorsal fin in teleost fishes: experimental analysis of wake forces in sunfish

2001 ◽  
Vol 204 (17) ◽  
pp. 2943-2958 ◽  
Author(s):  
Eliot G. Drucker ◽  
George V. Lauder
Keyword(s):  
High Speed ◽  
Lepomis Macrochirus ◽  
The Body ◽  
Cycle Period ◽  
Teleost Fishes ◽  
Caudal Fin ◽  
Locomotor System ◽  
Pectoral Fins ◽  
Dorsal Fin

SUMMARYA key evolutionary transformation of the locomotor system of ray-finned fishes is the morphological elaboration of the dorsal fin. Within Teleostei, the dorsal fin primitively is a single midline structure supported by soft, flexible fin rays. In its derived condition, the fin is made up of two anatomically distinct portions: an anterior section supported by spines, and a posterior section that is soft-rayed. We have a very limited understanding of the functional significance of this evolutionary variation in dorsal fin design. To initiate empirical hydrodynamic study of dorsal fin function in teleost fishes, we analyzed the wake created by the soft dorsal fin of bluegill sunfish (Lepomis macrochirus) during both steady swimming and unsteady turning maneuvers. Digital particle image velocimetry was used to visualize wake structures and to calculate in vivo locomotor forces. Study of the vortices generated simultaneously by the soft dorsal and caudal fins during locomotion allowed experimental characterization of median-fin wake interactions.During high-speed swimming (i.e. above the gait transition from pectoral- to median-fin locomotion), the soft dorsal fin undergoes regular oscillatory motion which, in comparison with analogous movement by the tail, is phase-advanced (by 30% of the cycle period) and of lower sweep amplitude (by 1.0cm). Undulations of the soft dorsal fin during steady swimming at 1.1bodylengths−1 generate a reverse von Kármán vortex street wake that contributes 12% of total thrust. During low-speed turns, the soft dorsal fin produces discrete pairs of counterrotating vortices with a central region of high-velocity jet flow. This vortex wake, generated in the latter stage of the turn and posterior to the center of mass of the body, counteracts torque generated earlier in the turn by the anteriorly positioned pectoral fins and thereby corrects the heading of the fish as it begins to translate forward away from the turning stimulus. One-third of the laterally directed fluid force measured during turning is developed by the soft dorsal fin. For steady swimming, we present empirical evidence that vortex structures generated by the soft dorsal fin upstream can constructively interact with those produced by the caudal fin downstream. Reinforcement of circulation around the tail through interception of the dorsal fin’s vortices is proposed as a mechanism for augmenting wake energy and enhancing thrust.Swimming in fishes involves the partitioning of locomotor force among several independent fin systems. Coordinated use of the pectoral fins, caudal fin and soft dorsal fin to increase wake momentum, as documented for L. macrochirus, highlights the ability of teleost fishes to employ multiple propulsors simultaneously for controlling complex swimming behaviors.

1. On New and Little-known Fossil Fishes from the Edinburgh District. No. III

1878 ◽  
Vol 9 ◽  
pp. 427-444
Author(s):  
R. H. Traquair
Keyword(s):  
Extreme Point ◽  
Anterior Part ◽  
Lower Lobe ◽  
The Body ◽  
Post Mortem ◽  
Caudal Fin ◽  
Dorsal Fin ◽  
Science And Art ◽  
Peculiar Form ◽  
General Appearance

Elonichthys ovatus, sp. nov. Traquair.Of this I have only seen one specimen, from the limestone of Burdiehouse, and preserved in the Edinburgh Museum of Science and Art.Description.—Allowing for the anterior part of the head, which is deficient, the entire length of the specimen to the extreme point of the upper lobe of the caudal fin would be about 5⅝ inches; the greatest depth of the body in front of the dorsal fin is 1½ inch. The distance from the origin of the pectoral fin to that of the ventral is a little over 1 inch, to opposite the commencement of the dorsal 1¼ inch, to opposite that of the anal 1½ inch, and to opposite that of the lower lobe of the caudal nearly 3 inches. The general form of the fish is thus remarkably short, deep, and ovoid, and its general appearance does not indicate that its peculiar form is due to post mortem distortion or change.

Schistura madhavai, a new species of hill-stream loach from Sri Lanka, with redescription of S. notostigma (Teleostei: Nemacheilidae)

Zootaxa ◽  
2017 ◽  
Vol 4311 (1) ◽  
pp. 96 ◽  
Author(s):  
HIRANYA SUDASINGHE
Keyword(s):  
New Species ◽  
Sri Lanka ◽  
Lateral Line ◽  
The Body ◽  
Pairwise Distance ◽  
Caudal Fin ◽  
Dorsal Fin ◽  
Fin Ray ◽  
Line Ending ◽  
Pelvic Fin

Schistura madhavai, new species, is described from Suriyakanda, Sri Lanka. It is distinguished from all other species of Schistura in the peninsula of India and Sri Lanka by the combination of the following characters: 8–9 wide, brown postdorsal bars separated by narrow, white interspaces; width of interspaces ¼–⅓ times width of bars; black bar at caudal-fin base wider than interspaces on the body; incomplete lateral line, ending beneath dorsal-fin base; absence of an axillary pelvic lobe; adpressed pelvic fin just reaching anus; origin of the pelvic fin on a vertical through the last unbranched dorsal-fin ray. Schistura notostigma, the only other Sri Lankan species of Schistura, is redescribed. It can be distinguished from all other species of Schistura in the peninsula of India and Sri Lanka by the combination of the following characters: 6–7 wide, brown postdorsal bars; width of interspaces ½–1 times width of bars; complete, black bar at caudal-fin base narrower than width of interspaces between bars on body; emarginate caudal fin; incomplete lateral line ending beneath dorsal-fin base; adpressed pelvic fin surpassing anus; and origin of pelvic fin beneath first branched dorsal-fin ray. Schistura madhavai is separated from S. notostigma by an uncorrected pairwise distance of 3.0–3.8% for the 16S rRNA gene fragment. 

Site specificity of Gyrodactylus salaris Malmberg, 1957 (Monogenea) on Atlantic salmon (Salmo salar L.) in the River Lakselva, northern Norway

1992 ◽  
Vol 70 (2) ◽  
pp. 264-267 ◽  
Author(s):  
Arne Johan Jensen ◽  
Bjørn Ove Johnsen
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Infection Intensity ◽  
The Body ◽  
Site Specificity ◽  
Caudal Fin ◽  
Northern Norway ◽  
Dorsal Fin ◽  
Atlantic Salmon Salmo Salar

Site specificity of Gyrodactylus salaris on 853 Atlantic salmon (Salmo salar) parr infected with 1 – 10 625 parasites was studied in the River Lakselva in northern Norway. At low intensities (< 100), the dorsal fin was the principal site of attachment, followed by the pectoral and anal fins. However, the distribution of parasites on the fish, and their crowding, varied with infection intensity. When the intensity increased to more than 100, more parasites were located on the caudal fin, and when it exceeded 1000, the body of the fish was also heavily infected.

Possible Adaptive Significance of Certain Enzyme Polymorphisms in Steelhead Trout (Salmo gairdneri)

1979 ◽  
Vol 36 (5) ◽  
pp. 544-551 ◽  
Author(s):  
J. M. Redding ◽  
C. B. Schreck
Keyword(s):  
High Temperature ◽  
Lactate Dehydrogenase ◽  
Dissolved Oxygen ◽  
Isocitrate Dehydrogenase ◽  
Adaptive Significance ◽  
Salmo Gairdneri ◽  
Parental Effects ◽  
Steelhead Trout ◽  
Intrinsic Properties ◽  
Juvenile Trout

In experimentally reared winter steelhead trout (Salmo gairdneri) fry, mean weights, lengths, and condition factors of three isozyme phenotypes of lactate dehydrogenase (LDH) enzyme differed significantly. Time of emergence from the gravel was unrelated to LDH phenotype. Relative mortality of the phenotypes between eyed-egg stage and emergence was unaffected by different subgravel conditions of temperature and dissolved oxygen. Differential tolerance to acute challenges of high temperature and low dissolved oxygen was observed between phenotypes of isocitrate dehydrogenase (IDH) enzyme and LDH in juvenile trout. Parental effects may have biased the result for LDH. Differences between IDH phenotypes may be related to intrinsic properties of variant isozymes. Key words: isozymes, lactate dehydrogenase, isocitrate dehydrogenase, temperature, dissolved oxygen, adaptive significance, Salmo gairdneri

scholarly journals Physoschistura dikrongensis, a new loach from Arunachal Pradesh, India (Teleostei: Nemacheilidae)

Zootaxa ◽  
2012 ◽  
Vol 3586 (1) ◽  
pp. 249 ◽  
Author(s):  
Y. LOKESHWOR ◽  
W. VISHWANATH
Keyword(s):  
New Species ◽  
Lateral Line ◽  
The Body ◽  
Arunachal Pradesh ◽  
Caudal Fin ◽  
Sensory Canal ◽  
Dorsal Fin ◽  
Fin Rays ◽  
Brahmaputra Basin ◽  
A New Species

A new species of nemacheilid, Physoschistura dikrongensis, is described from the Brahmaputra basin in ArunachalPradesh, India. It is easily distinguishable from congeners in having two V-shaped dark brown bars across the caudal fintowards the distal end; 11–15 irregular bars on the body; dark brown mottled markings on the head; 4 simple and 8½branched dorsal-fin rays; 4 simple anal-fin rays; an incomplete lateral line; a forked caudal fin with 8+7 branched rays; a well-developed axillary pelvic lobe; suborbital flap in males, and nine preoperculo-mandibular sensory canal pores.

A new species of Pachyurus Agassiz 1831 (Teleostei: Perciformes: Sciaenidae) from the Río Napo basin, Eastern Ecuador

Zootaxa ◽  
2002 ◽  
Vol 38 (1) ◽  
pp. 1 ◽  
Author(s):  
LILIAN CASATTI ◽  
NING LABBISH CHAO
Keyword(s):  
New Species ◽  
Lateral Surface ◽  
The Body ◽  
Caudal Peduncle ◽  
Caudal Fin ◽  
Longitudinal Stripe ◽  
Dorsal Fin ◽  
Coloration Pattern ◽  
A New Species

A new species of Neotropical freshwater sciaenid, Pachyurus stewarti, is described from the Río Napo basin, Ecuador. The new species is readily distinguishable from its congeners by having a unique coloration pattern of about twelve brownish vertical oval blotches and bars on the lateral surface of the body from the opercle to the caudal peduncle, and a longitudinal stripe which starts below the soft dorsal-fin base and extends along the mid-line of the caudal peduncle to the base of the caudal fin.

Ecsenius niue, new species of blenniid fish, and new distribution records for other species in the Opsifrontalis species group

Zootaxa ◽  
2002 ◽  
Vol 72 (1) ◽  
pp. 1 ◽  
Author(s):  
VICTOR G. SPRINGER
Keyword(s):  
New Species ◽  
Species Group ◽  
The Body ◽  
Body Contour ◽  
Caudal Fin ◽  
Dorsal Fin ◽  
Sw Pacific ◽  
Fin Ray ◽  
Niue Island ◽  
New Distribution

Ecsenius niue is described from Niue Island, SW Pacific. It is a member of the Opsifrontalis species group and is most similar to the Fijian endemic E. fijiensis, from which it differs in having six, as opposed to seven, vertical pairs of dark spots on the body posterior to a vertical from the base of the first segmented dorsal-fin ray, and in having the posteriormost pair of dark spots posteriorly elongate and attenuating onto the base of the caudal fin, as opposed to the spots being roughly circular and discrete. It differs from the superficially similar E. tigris (islands of the Queensland Plateau) in lacking the three or four dark spots on the body ventral to those on the dorsal body contour below the spinous dorsal fin. New distribution records are given for E. axelrodi, E. bathi, and E. opsifrontalis.

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