Some Chemical Signals in the Spawning Behavior of Rainbow Trout (Salmo gairdneri)

1973 ◽  
Vol 30 (7) ◽  
pp. 995-997 ◽  
Author(s):  
C. Newcombe ◽  
G. Hartman

In a two-choice maze ripe rainbow trout (Salmo gairdneri) of both sexes showed positive responses to chemical (probably olfactory) information. The possibility that visual or auditory stimuli influenced choice of channel in the maze was ruled out. Both males and females were strongly attracted to water taken from behind fish that were spawning and weakly attracted to the holding water of ripe fish that were not spawning. Brief speculation is offered about the role of chemical stimuli in the behavior of prespawning and spawning trout.

1975 ◽  
Vol 32 (5) ◽  
pp. 633-642 ◽  
Author(s):  
A. F. Tautz ◽  
C. Groot

Detailed accounts of the spawning behavior of chum salmon (Oncorhynchus keta) and rainbow trout (Salmo gairdneri) in laboratory flumes are provided. The behavioral activities, quivering, probing, and crossing over increase in frequency as a function of time prior to spawning whereas digging remains constant or decreases slightly. Maps of digging locations and movie films suggest nest shape and current pattern are monitored by the female, allowing her to intensify her digging activity near the center of the nest. Probing appears to be a signal to the male indicating approach of oviposition and also provides information to the female regarding the shape and suitability of the nest site. The probing act is also used in the synchronization of the male and female spawning acts. Changes in velocity do not appear to markedly affect nest construction either in terms of number of digs to oviposition or in size of nest constructed. It is inferred that velocity and gravel size are important insofar as they influence the construction of a suitable nest depression. Nest sites would appear to be selected on the basis of acceleration of flow rather than velocity per se though high limits must obviously exist.


2011 ◽  
Vol 143 (3) ◽  
pp. 245-253 ◽  
Author(s):  
Christelle Guédot ◽  
David R. Horton ◽  
Peter J. Landolt

AbstractWe examined the role of chemical signals in sex attraction of pear psylla, Cacopsylla pyricola (Förster), assessing the response of summerform male and female psyllids to male- and female-produced volatile chemicals. Male psyllids were attracted to odors from live females and pentane extracts of females. Extracts of females were as attractive to males as live females, suggesting that the female-produced volatile chemicals responsible for male attraction might be isolated by extracting females with pentane. Females were not attracted to odorants from live females and tended to avoid odorants from extracts of females. Furthermore, summerform males and females were not attracted or repelled by male-produced odorants from live males or extracts of males. Results of olfactometer assays using male summerform C. pyricola are consistent with results from earlier studies with the winterform morphotype of this species.


Aquaculture ◽  
1987 ◽  
Vol 61 (3-4) ◽  
pp. 275-279 ◽  
Author(s):  
J. Stoss ◽  
L. Geries ◽  
W. Holtz

2000 ◽  
Vol 78 (2) ◽  
pp. 167-173 ◽  
Author(s):  
O Guillaume

Non-sexually active males and females of the cave-dwelling salamander Proteus anguinus always aggregate in the same shelters, either under stones or in fissures. However, it was not known if this behaviour results from chemical communication and (or) behavioural interactions among conspecifics. I tested the hypothesis that this is the case by using two-choice tests. The results showed that salamanders re-located their own shelter even when it was displaced. However, they preferred a shelter that belonged to a conspecific or contained faecal pellets of a conspecific to their own or a control "blank" shelter. When two salamanders were simultaneously given the choice between two blank shelters, they cohabited. When they were simultaneously given the choice between their own shelter and each other's, they used them indiscriminately and frequently cohabited. These data provide evidence that P. anguinus use chemical signals as directional cues for homing and also for social behaviour. Chemical signals may attract conspecifics, which subsequently may exhibit gregarious behaviour by occupying common shelters.


1981 ◽  
Vol 59 (4) ◽  
pp. 629-636 ◽  
Author(s):  
Larry D. Witzel ◽  
Hugh R. MacCrimmon

The role of gravel size of unigranular diameters 2, 4, 8, 16, and 26.5 mm on ova survival and subsequent emergence of rainbow trout alevins is examined using a vertical-flow incubation apparatus. Survival to emergence, time of emergence, and alevin condition at emergence were signficantly influenced [Formula: see text] by gravel size. Mean percent survival to emergence increased with gravel size from a minimum of 1% in the 2-mm gravel to a maximum of 76% in the 26.5-mm gravel. Survival of control ova from gravel-free incubator was 88% to swim-up stage. Differences in percent survival were most significant within the 2 to 8 mm range. Poor survival of trout alevins in the finer gravels (2–4 mm) was the result of insufficient void space (entrapment). Days to first (43–58 days after ova burial) and 50% emergence (49–62 days after ova burial) also increased with gravel size. At a mean incubation temperature of 10.6 °C, the total emergence days was greatest (40 days) from the 8-mm gravel and occurred prematurely on day 37 after ova burial in 2-mm gravel. Alevin length and weight varied directly with gravel size, ranging from 2.17 to 2.39 cm and 11.9 to 126.8 mg, respectively. Larger alevins, which emerged later from coarser gravels had the least yolk reserve [Formula: see text] and the lowest KD values [Formula: see text], where KD is a developmental condition factor calculated from the ratio of wet weight to standard length. Premature emergence of free embryos and shortening of the alevin îmergence period in 2.0-mm gravel is identified as a stress response.


1976 ◽  
Vol 33 (2) ◽  
pp. 282-284 ◽  
Author(s):  
Hugh R. MacCrimmon ◽  
Christopher M. Hawkins

Laboratory studies on hatchery-reared wild juvenile rainbow trout (Salmo gairdneri) in an experimental raceway show no significant selection (P < 0.05) of test gravel substrates under either nonflowing or flowing (0.03 m/s) conditions regardless of rearing experience. There is no statistical evidence that hatchery conditioning of rainbow trout for gravel substrate selection is likely to be a feasible undertaking.


1982 ◽  
Vol 101 (1) ◽  
pp. 93-104 ◽  
Author(s):  
P. K. Bourne ◽  
A. R. Cossins

The rate of K+ influx in washed trout erythrocytes was not stable and declined by 60% over a 6 h period, but decreased only slowly thereafter. During this initial period the cells shrank, although [K+]i was maintained constant. Both ouabain-sensitive and furosemide-sensitive K+ influx were reduced by approximately equal amounts. Extensive modification of the saline composition produced no diminution of the loss of K+ influx activity, making it unlikely that the response was due to deficiencies in saline composition. The rate of K+ influx in unwashed cells was affected only slightly by noradrenaline and adrenaline. By contrast, K+ influx in cells which had been washed and incubated overnight before assay was stimulated 100–250% by these hormones. Half-maximal stimulation was at 2 X 10(−6) and 8 X 10(−6) M respectively. Replacement of plasma by a saline containing 5 X 10(−6) M adrenaline and noradrenaline resulted in high and stable K+ influx rates over a 6 h period. These results support the hypothesis that K+ influx in erythrocytes of freshly drawn blood is high as a result of stimulation by catecholamine hormones. Removal of the normal hormonal milieu, by washing of the cells, results in the rapid loss of K+ influx activity.


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