Competition for Food Between Redside Shiners (Richardsonius balteatus) and Rainbow Trout (Salmo gairdneri) in Two British Columbia Lakes

1961 ◽  
Vol 18 (2) ◽  
pp. 203-220 ◽  
Author(s):  
R. E. Johannes ◽  
P. A. Larkin
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Interspecific Competition ◽  
Stomach Contents ◽  
Salmo Gairdneri ◽  
Interspecific Aggression ◽  
Large Numbers ◽  
Competition For Food ◽  
Biological Environment ◽  
Richardsonius Balteatus

The distribution, movements, behaviour and food of trout and shiners in Paul and Pinantan Lakes were studied to determine the items and mechanisms of interspecific competition between them. Data from recent years were compared with data for years when trout alone inhabited the lakes.No interspecific aggression was observed. The possibility that the two species were competing for space was discounted. Stomach contents of shiners in Pinantan Lake revealed a marked qualitative diurnal food cycle. In Paul Lake, shiners have drastically reduced the Gammarus population relative to its pre-shiner abundance, forcing trout, as well as the shiners themselves, to shift their diets to other foods. This overgrazing was caused by the concentration of large numbers of shiners over the shoals where Gammarus are also present in their highest concentrations, and the ability of shiners to pursue food deeper into the weeds and to graze an area more thoroughly than trout. In Pinantan Lake, shiners have apparently reduced the density of Daphnia to a point where trout are unable to feed on them as rapidly as in pre-shiner years. The ability of both species to utilize many types of food tends to reduce the intensity of competition.The study demonstrates how false implications may arise from an appraisal of competition not initiated until after the effects of competition have been observed. If observations had not been made on Paul Lake until after competition had been observed, the importance of Gammarus as an item of competition would probably have been overlooked and the whole competitive relationship misconstrued.Environmental factors and behaviour were shown to be important influences on the dynamics of competition. The physical and biological environment and the distribution and behaviour of competitors may be in states of continual flux in which case the niches of the competitors cannot be considered constant.

Food Specialization By Individual Trout

1972 ◽  
Vol 29 (11) ◽  
pp. 1615-1624 ◽  
Author(s):  
James E. Bryan ◽  
P. A. Larkin
Keyword(s):  
Rainbow Trout ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Stomach Contents ◽  
Cutthroat Trout ◽  
Salmo Gairdneri ◽  
Potential Prey ◽  
Repeated Observation ◽  
Size Growth ◽  
Salmo Clarki

Analyses of stomach contents showed that the kinds of prey eaten by brook trout (Salvelinus fontinalis), cutthroat trout (Salmo clarki), and rainbow trout (Salmo gairdneri) were seldom distributed at random among the individuals. Repeated observation of food eaten by individuals in a stream and ponds showed that prey types were eaten in proportions which were characteristic for an individual.Specialization occurred on several different kinds of prey. Although the degree of specialization was higher during shorter intervals, the data suggested that some specialization persisted for half a year. There were no striking correlations between degree of specialization and other individual properties such as size, growth rate, weight of food, number of food items, previous specialization, or area of recapture.In addition to the observations on trout in relatively undisturbed habitats, a field experiment was conducted using laboratory-reared rainbow trout held in small ponds. The food of each trout in the experiment was sampled repeatedly. In analysis of variance, interaction among the individuals and kinds of prey eaten showed that food specialization occurred. Both the absolute and relative abundance of potential prey were constant during the experiment.

Feeding Activity and Rates of Digestion of Northern Squawfish (Ptychocheilus oregonensis)

1974 ◽  
Vol 31 (4) ◽  
pp. 411-420 ◽  
Author(s):  
Lance W. Steigenberger ◽  
P. A. Larkin
Keyword(s):  
Sockeye Salmon ◽  
Feeding Activity ◽  
Initial Period ◽  
Stomach Contents ◽  
Salmo Gairdneri ◽  
Peak Activity ◽  
Regression Techniques ◽  
Redside Shiner ◽  
Richardsonius Balteatus ◽  
Rapid Evacuation

Trapnet catches of northern squawfish (Ptychocheilus oregonensis) at Griffen and Cultus lakes, British Columbia, indicated peak activity and feeding in the twilight and dark hours. At Griffen Lake, squawfish force-fed 2.0 g of redside shiner (Richardsonius balteatus), and held at 17–20 C, digested at a rate of roughly 14%/h. At Cultus Lake, squawfish trapped during the peak of feeding activity, and held at 10–12 C, were sacrificed at 6-h intervals, and showed a digestion rate of sockeye salmon (Oncorhynchus nerka) smolts of 14%/h. Larger fish ate larger volumes of food. Regression techniques are not completely adequate for describing the course of digestion, which apparently involves an initial period of retention of food, followed by a fairly rapid evacuation of most of the ingested material. Most fish cleared their stomach contents in 24 h, and one half had done so between 12 and 18 h. In the laboratory, squawfish force-fed rainbow trout (Salmo gairdneri) had rates of digestion which increased with temperature, from about 5%/h at 4–6 C, to 40–50%/h at 24 C. Larger weights of food were digested at slower rates, but there were no consistent differences in rate of digestion by different sizes of squawfish.The rates of digestion are higher than those reported for various predatory European fishes.

Nest digging behavior of rainbow trout (Salmo gairdneri)

1970 ◽  
Vol 48 (6) ◽  
pp. 1458-1462 ◽  
Author(s):  
G. F. Hartman
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Wild Population ◽  
Salmo Gairdneri ◽  
Tactile Stimuli ◽  
Digging Behavior ◽  
Nest Digging

A wild population of rainbow trout (Salmo gairdneri) was observed during spawning in the Lardeau River in southeastern British Columbia, in April and May in 1966 and 1967. Nest digging in the first few days of spawning in 1967 was predominantly nocturnal, but diurnal nest digging increased until activity was nearly steady around the clock.Rate of digging (digging bouts per 10-min interval) averaged near five before spawning, rose sharply immediately after spawning, and then decreased. The number of body flexures per bout of digging was near six before spawning, decreased sharply right after spawning, and then rose progressively over a 50-min period. Touching or feeling the bottom of the nest was frequent before spawning and decreased after. The effect of internal stimuli (egg release) and tactile stimuli on digging behavior is considered.

Renal portal phagocytosis of bacteria in rainbow trout (Salmo gairdneri Richardson): ultrastructural observations

1984 ◽  
Vol 62 (12) ◽  
pp. 2505-2511 ◽  
Author(s):  
H. W. Ferguson
Keyword(s):  
Endothelial Cells ◽  
Electron Microscope ◽  
Rainbow Trout ◽  
Salmo Gairdneri ◽  
Portal Circulation ◽  
Prominent Feature ◽  
Large Area ◽  
Large Numbers

Catheterized rainbow trout (Salmo gairdneri) were inoculated with killed bacteria and the perfused – fixed kidney was examined in the electron microscope. The endothelium of the portal circulation was continuous but had evidence of marked pinocytotic activity with large numbers of intracytoplasmic vesicles, many of which were spiny coated. Intracytoplasmic transfer tubules were also a prominent feature. Bacteria were phagocytosed by macrophages closely associated with the endothelium, but not by the endothelial cells. Macrophage pseudopodia were occasionally seen traversing endothelium to touch the underlying haemopoietic tissue. The renal portal vasculature provides a large area for efficient antigen trapping.

First Record of Bacterial Kidney Disease in an Apparently Wild Salmonid in British Columbia

1973 ◽  
Vol 30 (10) ◽  
pp. 1578-1580 ◽  
Author(s):  
T. P. T. Evelyn ◽  
G. E. Hoskins ◽  
G. R. Bell
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Kidney Disease ◽  
First Record ◽  
Wild Fish ◽  
Salmo Gairdneri ◽  
Bacterial Kidney Disease ◽  
Causative Bacterium

A confirmed case of bacterial kidney disease in a sports-caught rainbow trout (Salmo gairdneri) from Loon Lake, British Columbia, is reported. The case represents the first record of this disease in an apparently wild fish in this province. Descriptions of the affected trout and of the causative bacterium are provided.

Lakeward Migration of Young Rainbow Trout (Salmo gairdneri) in the Upper Lardeau River, British Columbia

1969 ◽  
Vol 26 (1) ◽  
pp. 33-45 ◽  
Author(s):  
T. G. Northcote
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Water Temperature ◽  
Water Current ◽  
Salmo Gairdneri ◽  
Field Observations ◽  
Predominant Role ◽  
Emergence Period ◽  
Trout Lake ◽  
Kootenay Lake

Lakeward migration of rainbow trout fry was studied in the upper Lardeau River, where the young emerge from a spawning area immediately below the outlet of Trout Lake utilized by large trout from Kootenay Lake, about 56 km downstream. Most fry move downstream towards Kootenay Lake shortly after emergence; however, some, particularly later in the emergence period, move upstream into Trout Lake. Field observations and experiments suggest that water temperature may be important in inducing different responses to water current in these fish, but may not play such a predominant role or operate at the same levels as proposed earlier for control of young trout migration in the Loon Lake system.

A Predator–Prey Interaction in Freshwater Fish

1959 ◽  
Vol 16 (3) ◽  
pp. 269-281 ◽  
Author(s):  
E. J. Crossman
Keyword(s):  
Growth Rate ◽  
Rainbow Trout ◽  
Water Temperature ◽  
Freshwater Fish ◽  
Salmo Gairdneri ◽  
Lake Morphometry ◽  
Predator Prey ◽  
Prey Interaction ◽  
Redside Shiner ◽  
Richardsonius Balteatus

The predator–prey interaction of rainbow trout, Salmo gairdneri Richardson, and the redside shiner, Richardsonius balteatus (Richardson), in Paul Lake, British Columbia, depends on such factors as distribution and movements of predator and prey, behaviour of predator and prey, lake morphometry, shoal water temperature and characteristics of the fish.In adult trout, activity associated with predation follows a stereotype pattern. Behaviour may also be responsible for the fact that trout under 10 inches in length do not utilize, as food, even small shiners to any extent, even though under laboratory conditions they will kill and eat them. The estimated annual kill of shiners by predatory trout is 150,000 and the shiner population is probably in the millions. Shiners preyed on are such that predation appears not to limit recruitment to the prey population. Shortly after their introduction to the lake shiners reduced the growth rate of small trout by competition. There is evidence that feeding on shiners now increases the growth rate of at least those trout over 14 inches whose food is as high as 98% shiners in summer.

The life histories and trophic relationships of the Trichoptera of Marion Lake, British Columbia

1971 ◽  
Vol 49 (5) ◽  
pp. 623-635 ◽  
Author(s):  
Michael J. Winterbourn
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Life Histories ◽  
Oncorhynchus Nerka ◽  
Trophic Relationships ◽  
Salmo Gairdneri ◽  
Taricha Granulosa ◽  
Kokanee Salmon ◽  
Competitive Species ◽  
Species Being

Life histories and trophic relationships of Trichoptera were studied in a small British Columbia lake. Larvae of 10 caddis species were primarily sediment feeders, 2 were leaf feeders, 3 carnivores, and 1 Banksiola crotchi, an algal feeder in early instars and predaceous in later ones. The final instar larvae of potentially competitive species tended to be separated in time. Caddis larvae were an important component of the diet of rainbow trout (Salmo gairdneri), species being preyed upon sequentially as their later instars appeared in the lake. Larvae were also important as prey of the salamander Taricha granulosa but were less significant in the diets of kokanee salmon (Oncorhynchus nerka) and a second salamander Ambystoma gracile.

Report of the metacestode of Paradilepis simoni Rausch, 1949 (Cyclophyllidea: Dilepidae) from fish in British Columbia

1982 ◽  
Vol 60 (2) ◽  
pp. 184-186 ◽  
Author(s):  
Hilda Lei Ching
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Oncorhynchus Nerka ◽  
Salmo Gairdneri ◽  
Size And Shape ◽  
Larval Stages ◽  
Prosopium Williamsoni

Larval stages of tapeworms were found encysted in the livers of the following fish: 77% of 87 Oncorhynchus nerka (Walbaum), kokanee; 22% of 111 Salmo gairdneri (Richardson), rainbow trout; 13% of 113 Ptychocheilus oregonensis (Richardson), northern squawfish; 3% of 98 Prosopium williamsoni (Girard), mountain whitefish; and 2% of 85 Cottus asper (Richardson), prickly sculpin. The metacestodes were identified to be that of Paradilepis simoni from the number, size, and shape of the rostellar hooks.

The development of Philonema oncorhynchi (Nematoda: Philometridae) in Cyclops bicuspidatus in relation to temperature

1969 ◽  
Vol 47 (3) ◽  
pp. 307-312 ◽  
Author(s):  
Ronald C. Ko ◽  
James R. Adams
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Larval Development ◽  
Sockeye Salmon ◽  
Natural Infection ◽  
Salmo Gairdneri ◽  
Infective Stage ◽  
Final Size ◽  
Rate Of Development ◽  
Larval Stages

Development of Philonema oncorhynchi was followed in Cyclops bicuspidatus kept at 4°, 10°, and 15 °C. The nematode molted twice in the haemocoel of copepods. Three larval stages are described. The final size of the infective stage was unaffected by temperature. The rate of larval development was directly proportional to temperature between 4° and 15 °C. An increase of 5 °C halved the rate. The significance of these findings to the natural infection of sockeye salmon in Cultus Lake, British Columbia, is discussed.The development of P. agubernaculum from the rainbow trout, Salmo gairdneri, was studied at 10 °C by the same methods. Morphological features and rate of development were similar to those of P. oncorhynchi.

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