Size Selective Predation Among Juvenile Salmonid Fishes in a British Columbia Inlet

1971 ◽  
Vol 28 (10) ◽  
pp. 1503-1510 ◽  
Author(s):  
Robert R. Parker
Keyword(s):  
Growth Rate ◽  
British Columbia ◽  
Prey Population ◽  
Oncorhynchus Gorbuscha ◽  
Field Observations ◽  
Salmonid Fishes ◽  
Selective Predation ◽  
Initial Size ◽  
Salmon Fry ◽  
Series Of Experiments

Field observations suggest early sea mortality of pink (Oncorhynchus gorbuscha) and chum (O. keta) salmon fry is largely due to predation by juvenile coho (O. kisutch) salmon. A series of experiments demonstrates a strong bias toward the smaller individuals of the prey population. This results in an apparent growth rate 0.3–0.5% per day due to the biased mortality alone. With a high innate growth rate [Formula: see text], the prey are shown to "outgrow" the predator [Formula: see text], and hence become unavailable. Chums are shown to have an advantage over pinks through slightly earlier entry into the estuary and a larger initial size. The mechanism of selection used by the predator is not known from this study.

Orientation of Pink Salmon (Oncorhynchus gorbuscha) During Early Marine Migration from Bella Coola River System

1967 ◽  
Vol 24 (11) ◽  
pp. 2321-2338 ◽  
Author(s):  
M. C. Healey
Keyword(s):  
British Columbia ◽  
Pink Salmon ◽  
River System ◽  
Early Morning ◽  
Oncorhynchus Gorbuscha ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Salmon Fry ◽  
Marine Migration ◽  
Bella Coola

During May and June 1966, the migration of pink salmon fry from the Bella Coola River was studied in Burke Channel, British Columbia. The movement of pink fry down Burke Channel was saltatory. Short periods of active migration were interspersed with longer periods when the fry did not migrate and accumulated in bays. Fry were sampled from these accumulations and their ability to orient using celestial cues was examined. During the early morning, fry tended to prefer directions at right angles to their direction of migration, but at other times of the day preferred the direction of migration. The preference for the direction of migration was strongest at midday. Fry were better oriented on clear days than on cloudy days. These data indicate that fry may use celestial cues to find directions during their oceanic migrations.

Daily Patterns of Feeding Behavior, Daily Rations, and Diets of Juvenile Pink Salmon (Oncorhynchus gorbuscha) in Two Marine Bays of British Columbia

1981 ◽  
Vol 38 (1) ◽  
pp. 10-15 ◽  
Author(s):  
Jean-Guy J. Godin
Keyword(s):  
British Columbia ◽  
Feeding Behavior ◽  
Littoral Zone ◽  
Pink Salmon ◽  
Early Period ◽  
Oncorhynchus Gorbuscha ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Salmon Fry ◽  
Harpacticoid Copepods ◽  
Additional Support

Stomach analyses showed that pink salmon fry fed mainly during daylight hours in the littoral zone of Departure Bay and Hammond Bay, British Columbia, in May. Although the diurnal feeding patterns of the fish differed slightly between the two bays, maximum mean prey biomass in the fishes' stomachs occurred near or at dusk in both bays. Daily rations consumed by Departure Bay and Hammond Bay fish were estimated to be 13.1 and 6.6% of their dry body weight, respectively. The fry consumed similar prey items in both bays, but in differing proportions. Harpacticoid copepods, copepod nauplii, and barnacle larvae comprised numerically 93.1 and 86.2% of the diets of Departure Bay and Hammond Bay fish, respectively. About 38% of the diet of Departure Bay fish and 51% of the diet of Hammond Bay fish comprised epibenthic prey, mainly harpacticoid copepods. The data provide additional support for the importance of the detritus-microbe-consumer type food chain supporting the production of pink salmon during their early period of marine residency.Key words: pink salmon, feeding behavior, daily rhythm, diet, ration, British Columbia

Homing Tendency and Age at Maturity of Pink Salmon (Oncorhynchus gorbuscha) in British Columbia

1939 ◽  
Vol 4b (4) ◽  
pp. 233-251 ◽  
Author(s):  
A. L. Pritchard
Keyword(s):  
British Columbia ◽  
East Coast ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Age At Maturity ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Salmon Fry ◽  
Second Year ◽  
Transplantation Experiments

Pink salmon fry were marked by the removal of certain fins to ensure later identification as adults. This procedure does not affect the growth or the feeding reactions of the fish. Three experiments were conducted on natural runs at McClinton creek, Masset inlet, B.C. On the basis of the most significant one of these it is concluded that the majority of the fish return to spawn in the stream in which they were hatched. Isolated individuals, in numbers not economically significant, may wander to a distance of 400 miles (645 kilometres). In the case of fry resulting from transplantation experiments from Tlell river, east coast of Graham island, to McClinton creek, there appears no consistent behaviour in regard to "homing". For fry, hatchery-raised and pond-reared, from Vedder river, Swelter creek eggs, no return to the parent stream was reported. All pink salmon mature in the autumn of their second year. Certain incidental checks in growth have been discovered on scales which should not be interpreted as representing a winter.

Logging Impacts and Some Mechanisms that Determine the Size of Spring and Summer Populations of Coho Salmon Fry (Oncorhynchus kisutch) in Carnation Creek, British Columbia

1984 ◽  
Vol 41 (7) ◽  
pp. 1097-1105 ◽  
Author(s):  
J. C. Scrivener ◽  
B. C. Andersen
Keyword(s):  
Growth Rate ◽  
British Columbia ◽  
Growth Rates ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Growing Season ◽  
Channel Morphology ◽  
Creek Watershed ◽  
Salmon Fry ◽  
Logging Impacts

Natural patterns in emergence times, seaward movements, instream distributions, densities, and growth of coho salmon fry (Oncorhynchus kisutch) between March and September are contrasted with patterns observed during and after logging in the Carnation Creek watershed. After streamside logging in 1976–77, fry emerged up to 6 wk earlier and moved seaward more quickly than during years before logging. These observations are attributed to higher water temperatures during the winter and to emergence during a period of more frequent freshets. Increased fry movement from the stream could result in habitat being underutilized. In sections affected by intense streamside logging, the deposition of "fine" logging debris led to increased fry densities during the summers of 1977 and 1978. After major freshets in November 1978, which removed this fine debris and affected channel morphology in these sections, fry densities declined below those observed prior to logging. Growth rate of fry was inversely correlated with density in all stream sections. Growth rates, after correction for density, tended to be greater in all sections after the adjacent streamside was logged. Larger fry and more variable numbers of fry remained in the stream in September after logging than before logging. Their increased size is attributed to the longer growing season afforded by earlier emergence. This complex of interacting factors determines the number and size of fry in autumn and it can influence the production of smolts the following spring.

Growth Rate of Central British Columbia Pink Salmon (Oncorhynchus gorbuscha)

1964 ◽  
Vol 21 (5) ◽  
pp. 1101-1128 ◽  
Author(s):  
R. J. LeBrasseur ◽  
R. R. Parker
Keyword(s):  
Growth Rate ◽  
British Columbia ◽  
Pink Salmon ◽  
Growth Period ◽  
Oncorhynchus Gorbuscha ◽  
Instantaneous Growth Rate ◽  
Commercial Fishery ◽  
Instantaneous Rate ◽  
Instantaneous Growth ◽  
Rate Of Increase

Pink salmon were sampled at various stages, as fry and fingerling in enclosed waters, as juveniles and subadults in the ocean and as maturing salmon in the commercial fishery. On the basis of length frequency data and from recapture measurements of marked and tagged individuals the instantaneous growth rate in length (gl) for successive 30-day periods was computed. As a result three major growth stanzas were recognized. Following the entrance of fry into the estuary, growth was approximately exponential (gl = 0.559) during an initial 40-day period. Fish increased in length from 3.5 to 8.4 cm. Thereafter, the instantaneous rate of growth gradually declined to a minimum in March (gl = 0.076). During this time the length increased from 8.4 to 32.5 cm. The final growth period was marked by a rapid rate of increase in length in late April and early May (gl = 0.171), followed by a declining rate of increase in length which was finally terminated after the fish had re-entered the coastal waters and the commercial fishery (gl = 0.041). The length data were transformed to weight data from a generalized length–weight regression. During the initial 30-day period the instantaneous growth rate in weight, gw = 6.53. From a value of gw = 2.87 for late May and early June the instantaneous growth rate progressively fell to a low of gw = 1.28 for late March to early April. During late April to early May of the ultimate year, gw = 1.74. The instantaneous growth rate then fell to gw = 1.14 during mid July to early August. It was concluded that growth, in length and weight, of central British Columbia pink salmon is a continuing process with no period of complete cessation from the time the fry enter the sea until the time they re-enter the estuary as adults.

Supplementary Checks on the Scales of Pink Salmon (Oncorhynchus gorbuscha) and Chum Salmon (O. keta)

1965 ◽  
Vol 22 (6) ◽  
pp. 1477-1489 ◽  
Author(s):  
H. T. Bilton ◽  
W. E. Ricker
Keyword(s):  
British Columbia ◽  
Chum Salmon ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Commercial Fisheries ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Clear Cut ◽  
Second Year Of Life ◽  
Second Year ◽  
Similar Incidence

Among 159 central British Columbia pink salmon that had been marked by removal of two fins as fry and had been recovered in commercial fisheries after one winter in the sea, the scales of about one-third showed a supplementary or "false" check near the centre of the scale, in addition to the single clear-cut annulus. This evidence from fish of known age confirms the prevailing opinion that such extra checks do not represent annuli, hence that the fish bearing them are in their second year of life rather than their third. Unmarked pink salmon from the same area, and some from southern British Columbia, had a generally similar incidence of supplementary checks. In both marked and unmarked fish the supplementary checks varied in distinctness from faint to quite clear. In a sample of scales of 14 double-fin marked chum salmon which were known to be in their 4th year, all fish had the expected 3 annuli, and 12 fish had a supplementary check inside the first annulus.

scholarly journals Rich Dynamics of a Predator-Prey System with Different Kinds of Functional Responses

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Kankan Sarkar ◽  
Subhas Khajanchi ◽  
Prakash Chandra Mali ◽  
Juan J. Nieto
Keyword(s):  
Growth Rate ◽  
Hopf Bifurcation ◽  
Dynamical Behavior ◽  
Prey Population ◽  
Uniform Persistence ◽  
Functional Responses ◽  
Normal Form Theory ◽  
Predator Prey ◽  
Center Manifold Theorem ◽  
Prey System

In this study, we investigate a mathematical model that describes the interactive dynamics of a predator-prey system with different kinds of response function. The positivity, boundedness, and uniform persistence of the system are established. We investigate the biologically feasible singular points and their stability analysis. We perform a comparative study by considering different kinds of functional responses, which suggest that the dynamical behavior of the system remains unaltered, but the position of the bifurcation points altered. Our model system undergoes Hopf bifurcation with respect to the growth rate of the prey population, which indicates that a periodic solution occurs around a fixed point. Also, we observed that our predator-prey system experiences transcritical bifurcation for the prey population growth rate. By using normal form theory and center manifold theorem, we investigate the direction and stability of Hopf bifurcation. The biological implications of the analytical and numerical findings are also discussed in this study.

scholarly journals EFFECT OF ILLUMINATION ON GROWTH AND BEHAVIOUR OF GUPPY, POECILIA RETICULATA

2020 ◽  
Vol 17 (35) ◽  
pp. 338-345
Author(s):  
Alexander B. RUCHIN
Keyword(s):  
Growth Rate ◽  
Specific Growth Rate ◽  
Poecilia Reticulata ◽  
Specific Growth ◽  
Light Transmission ◽  
Light Level ◽  
High Illumination ◽  
Series Of Experiments ◽  
Juvenile Behavior ◽  
Effect Of Light

The guppy, Poecilia reticulata, is a model for many ichthyological studies. The effect of light on juvenile growth has been studied on the Poecilia reticulata. Studies have been conducted in twenty-liter aquariums. For experiments on the fish arbitrary choice of light intensity (light transmission behavior), it was used radiant pans of organic glass 150 x 15 x 15 cm divided by transparent semi-partitions into ten communicating compartments. The specific growth rate has been determined after the experiments. It increases with the light level increasing. The growth rate is minimal at 0 lx in all series of experiments. It was shown that the sharpest increase in the specific growth rate of guppies occurred when the illumination changed from 0 to 200 lx. A further increase in the intensity of illumination practically did not affect the growth of guppies. Also, the guppy juvenile behavior has been studied in special trays at different light from 3200 to 5900 lx. The motor activity of guppies increases by 30% in lightgradient conditions. The frequency (25 sec) and length of guppies stay (28.3 sec) are the highest in the compartment with 4700 lx. The preferential light zone expands if the juveniles are starving. As the period of starvation increased, guppies began to swim almost equally often and linger in different light zones. Thus, high light conditions stimulate the search behavior and activity of guppies. To grow guppies in production conditions, high illumination is necessary.

Statistical Evaluation of a Large-Scale Fishing Experiment Designed to Test for a Genetic Effect of Size-Selective Fishing on British Columbia Pink Salmon (Oncorhynchus gorbuscha)

1992 ◽  
Vol 49 (7) ◽  
pp. 1294-1304 ◽  
Author(s):  
Murdoch K. McAllister ◽  
Randall M. Peterman ◽  
Darren M. Gillis
Keyword(s):  
British Columbia ◽  
Statistical Power ◽  
Large Scale ◽  
Pink Salmon ◽  
Genetic Effect ◽  
Oncorhynchus Gorbuscha ◽  
Causal Mechanism ◽  
Block Designs ◽  
Adult Size ◽  
Pink Salmon Oncorhynchus Gorbuscha

Since 1950, stocks of British Columbia pink salmon (Oncorhynchus gorbuscha) have shown up to a 34% decrease in mean adult body weight, causing significant reduction in economic value of commercial harvests. Previous research suggests that this trend is due to size-selective harvesting of large fish, but changes in oceanographic conditions are a plausible alternative. Corrective action by management agencies requires that the true causal mechanism be identified. We therefore examined several possible designs for a large-scale fishing experiment devised to test the size-selective fishing hypothesis. These designs would generate accurate and precise field estimates of the heritability (h2) of growth rate, which is important because it, in combination with the selection differential (D) caused by fishing, determines how rapidly body size changes. Monte Carlo simulations showed that block designs with three to six spatial replicates and relatively short durations generated high statistical power. For example, for h2 = 0.22, D = 0.25 kg, and four spatial replicates, an 8-yr experiment resulted in power = 0.87, which gave a SE < 0.10 for h2 = 0.22. We conclude that some experimental designs have good potential to test the possible effects of size-selective fishing on mean adult size of British Columbia pink salmon.

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