Interspecific interactions affecting the foraging behavior of chum salmon fry (Oncorhynchus keta)
department or school: Science, Faculty of
department or school: Zoology, Department of
data provider: DSpace
degree campus: UBCV
creator: Tompkins, Arlene Marie
issued: 2011-03-09T00:30:20Z
issued: 1991
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: Interactions between fish utilizing nearshore habitats of the Fraser River estuary were investigated by field observations and laboratory experiments. Chum salmon fry (Oncorhynchus keta) were the most abundant salmonid captured between April and June. Non-salmonid species captured included: threespine stickleback (Gasterosteus aculeatus), prickly sculpin (Coitus asper), and peamouth chub (Mylocheilus caurinus). Potential predators included: prickly sculpin, and northern squawfish (Ptychocheilus oregonensis), but few had been feeding on fish. Chum fry fed predominantly on surface insects but the proportion of benthic prey in the diet increased over time. Stickleback shared the greatest diet overlap with chum fry. Interactions between two dissimilar prey, chum fry and threespine stickleback, and a predator, cutthroat trout (Oncorhynchus clarki) were investigated in the laboratory. Prey response to hungry and satiated predators was related to the degree of risk. Although attack rates by trout on chum and stickleback were similar, trout captured more stickleback than chum, but consumed both prey at similar rates. I tested the hypotheses that prey foraging efficiency is reduced in the presence of a predator and increased in the presence of alternate prey. When alone, chum fed on surface Drosophila and mid-water Daphnia, while stickleback fed on benthic Tubifex and Daphnia. The feeding efficiency of chum increased in the presence of stickleback and decreased in the presence of trout. Hatchery and wild chum showed opposite dietary shifts in the presence of trout. Hatchery chum shifted from surface to mid-water feeding and the number of fish feeding significantly decreased. Wild chum fed at the surface, at significantly decreased feeding rates. In the presence of stickleback and trout the feeding behaviour of chum was similar to that when chum were alone. Stickleback feeding behaviour was not affected by presence of trout or chum. Chum and stickleback detected Daphnia faste…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/32177
note: Interspecif ic Interactions Af fec t ing T h e Foraging B e h a v i o r O f C h u m S a l m o n F r y (Oncorhynchus keta) Arlene Marie Tompkins B.Sc , St. Francis Xavier University, 1979 M . S c , University of Manitoba, 1982 A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of D O C T O R O F P H I L O S O P H Y in The Faculty of Graduate Studies Department of Zoology We accept this thesis as conforming to the required standard The University of British Columbia April 1991 © Arlene Marie Tompkins, 1991 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of The University of British Columbia Vancouver, Canada DE-6 (2/88) Abstract Interactions between fish utilizing nearshore habitats of the Fraser River estuary were investigated by field observations and laboratory experiments. Chum salmon fry (Oncorhynchus keta) were the most abundant salmonid captured between April and June. Non-salmonid species captured included: threespine stickleback (Gasterosteus aculeatus), prickly sculpin (Coitus asper), and peamouth chub (Mylocheilus caurinus). Potential predators included: prickly sculpin, and northern squawfish (Ptychocheilus oregonensis), but few had been feeding on fish. Chum fry fed predominantly on surface insects but the proportion of benthic prey in the diet increased over time. Stickleback shared the greatest diet overlap with chum fry. Interactions between two dissimilar prey, chum fry and threespine stickleback, and a predator, cutthroat trout (Oncorhynchus clarki) were inve…
has type: Thesis/Dissertation
is shown at: 10.14288/1.0101144
language: eng
degree discipline: Zoology
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/32177