The Effects of Spawning Sockeye Salmon, Oncorhynchus Nerka, on Small Streams in the Wood River Lakes, Alaska PDF Download
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Author: Douglas Paul Peterson
Publisher:
ISBN:
Category : Benthic animals
Languages : en
Pages : 114
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Author: Douglas Paul Peterson
Publisher:
ISBN:
Category : Benthic animals
Languages : en
Pages : 114
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Author: Molly T. McGlauflin
Publisher:
ISBN:
Category : Fish populations
Languages : en
Pages : 100
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Author: Daniel E. Eastman
Publisher:
ISBN:
Category : Fish communities
Languages : en
Pages : 184
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"The migration patterns, food habits and the overall body condition of resident fish populations were characterized with particular reference to spawning activity of sockeye salmon (Oncorhynchus nerka) in the Wood River lake system, AK. Juvenile and adult char (Salvelinus sp.) and rainbow trout (Oncorhynchus mykiss) moved into three of the four small study streams as salmon began to spawn, consumed large quantities of salmon eggs and other salmon-derived food items, and in most cases grew significantly (in weight) throughout the summer. Tag-recapture results indicated that rainbow trout, char and Arctic grayling (Thymallus arcticus) were moving substantially within the streams and that trout and grayling were migrating between streams (2.7-3.9 km) within the lake. Prior to salmon spawning, stomachs contained only small aquatic and terrestrial insects and, most fish were visibly emaciated. In Pick Creek salmon-derived food items dominated (>90% by weight) the diets of most fish for more than a month, with some individuals' stomachs containing more than 1,000 salmon eggs. During this time period, most species in the four streams were significantly heavier due to a combination of increased food consumption and growth. There were also costs associated with feeding in these small streams, as was evidenced by the high frequency of wounds inflicted upon resident fish by aggressive, spawning salmon. Grayling preyed primarily upon aquatic insects and did not exhibit significant growth throughout the salmon spawning season. Salmon-derived resources promote summer growth in those species which capitalize on their seasonal availability and may enhance survival in Arctic regions where the summer growth period is short and winter is severe"--Author's abstract.
Author: Setsuwo Tsunoda
Publisher:
ISBN:
Category : Fish surveys
Languages : en
Pages : 104
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The movements of a population of adult sockeye salmon (Oncorhynchus nerka) were followed in a small tributary of Brooks Lake, Alaska until spawning was nearly complete in 1963. The objectives of the study were to describe the movements of sockeye salmon on the spawning ground of an entire small stream, to determine factors related to such movements, and to consider the significance of the movements to the species. The spawning run was inventoried at a weir located near the mouth of the tributary. Portions of the run were sampled as they immigrated, and the sampled fish were tagged to enable subsequent identification of individual fish on the spawning ground. Following the initial immigration, daily observations were made to ascertain the location of all fish and the activities of the tagged fish. Tagging had no material effect on either dispersal in the stream or pairing of spawners. The spawning run totalled 2,495; the ratio of males to females was 2.27:1.00, The run consisted preponderantly of males that had spent two winters in the ocean (two ocean-years) and females that had spent three winters in the ocean (three ocean-years). They entered the tributary over a period of 14 days in two waves separated by an interval of three days. The overall median life span in the stream was 12 days in the first wave and eight days in the second wave. The difference was primarily due to predation on the salmon by the brown bear (Ursus arctos). The average female established a redd in 1.4 days; thereafter the females rarely moved far from their redds. The average male required 2.3 days to establish himself in a spawning locale; thereafter most males remained within a relatively small area. The males showed a decided tendency to remain in areas with a high density of females on redds. Fewer females than males overshot their spawning sites. No relation was found between the movements of spawners and either variations of water level or surface water temperature of the stream. Bear predation disrupted spawning activities only locally and temporarily. Males of three ocean-years paired with more females per male than did males of one or two ocean-years. But because of their greater numbers two-ocean-year males participated in more spawnings than did three-ocean-year males. The mean duration of pairing of a particular male with a particular female on a redd was 1.25 days. I concluded that homing within the tributary did not occur; therefore its spawning stock must be a homogeneous unit. The role of the male is primarily one of fertilization of the eggs, not one of defense of territory. Because of the abnormally high ratio of males to females, competition between males for spawning partners resulted in most males of one or two ocean-years being relegated to attend females paired with larger males. Conflict among the males was apparently largely confined within two separate classes of males: males 50 cm or shorter jockeyed among themselves for seemingly preferred positions of attendance next to a pair on a redd, while males 51 cm or longer competed for spawning partners. The polygamous habit in sockeye salmon usually results in a seeming excess of males on the spawning ground beyond the number required to fertilize the eggs. I propose that this "surplus" of males provides a safety factor in times of low numbers in a stock and the competition needed to disperse the males among the available females; both provisions insure fertilization of the available eggs, However, crucial experiments need to be done on an entire population of sockeye salmon with artificially reduced ratios of males to females to determine whether the movements of the spawners would result in an efficiency of egg fertilization sufficient to make harvesting of the "surplus" males feasible.
Author: Mark Zimmermann
Publisher:
ISBN:
Category : Scales (Fishes)
Languages : en
Pages : 238
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Author: Theodore R. Merrell
Publisher:
ISBN:
Category : Brooks Lake (Alaska)
Languages : en
Pages : 814
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Book Description
Ecological studies on the fresh-water phases of the life history of sockeye salmon and studies on related limnology and climatology were made at Brooks Lake, Alaska, in 1957. Data are presented and interpreted on adult sockeye salmon spawning distributions and behavior, age, sex, length, fecundity, and bear predation; on juvenile sockeye salmon ages, food, growth, migration from the lake, relative abundance, and distribution in the lake; and on climatological and limnological factors that may influence sockeye salmon behavior and abundance.
Author: Marcia Marie Bender
Publisher:
ISBN:
Category : Fish populations
Languages : en
Pages : 130
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Author: Melinda L. Rowse
Publisher:
ISBN:
Category : Fishes
Languages : en
Pages : 190
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Book Description
Author: Thomas P. Quinn
Publisher: UBC Press
ISBN: 0774842431
Category : Nature
Languages : en
Pages : 392
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Book Description
The Behavior and Ecology of Pacific Salmon and Trout explains the patterns of mate choice, the competition for nest sites, and the fate of the salmon after their death. It describes the lives of offspring during the months they spend incubating in gravel, growing in fresh water, and migrating out to sea to mature. This thorough, up-to-date survey should be on the shelf of everyone with a professional or personal interest in Pacific salmon and trout. Written in a technically accurate but engaging style, it will appeal to a wide range of readers, including students, anglers, biologists, conservationists, legislators, and armchair naturalists.
Author: Samuel Alexander May
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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The life histories of migratory species such as salmonids, sea turtles, and birds often involve return migrations between feeding and natal habitats. These natal homing behaviors are known to produce structured metapopulations, where geographic and demographic barriers result in non-random mating among many locally adapted subpopulations. The resulting spatial and temporal diversity across heterogeneous landscapes can buffer metapopulations against disruptive events that influence any one subunit. Dispersal and gene flow within and between subpopulations can reduce fitness losses due to inbreeding depression, influence rates of adaptation, and facilitate colonization or recolonization of newly available habitat. However, an understudied aspect of metapopulation biology is the influence of biotic and abiotic factors that lead to genetic structure within and between subpopulations, and the effects of this structure on fitness. Therefore, the overall goal of this thesis was to investigate how environmental, behavioral, and life-history variation might influence dispersal, population structure, and fitness within and between subpopulations. To accomplish this goal, dispersal within and between two proximate stream-spawning populations of Sockeye salmon (Oncorhynchus nerka): A and C Creeks on the Wood River System, Bristol Bay, AK was studied over two complete generations of returning adults. First, a panel of 172 SNP loci was developed (genotyping-in-thousands by sequencing; Chapter One) and used to reconstruct a pedigree from fish returning over a 14-year period, and to identify dispersers between the two populations. Second, we investigated the drivers and fitness consequences of dispersal between A and C Creeks and found that return timing to spawning grounds and within-season variation in predation and population density influenced dispersal between the two populations (Chapter Two). Fitness consequences of dispersal depended on the direction dispersers moved; moving from A to C increased absolute fitness of dispersers (compared to individuals in their natal population) but decreased their relative fitness (compared to individuals in their new spawning population), while moving from C to A decreased absolute fitness but increased relative fitness. From these results, we concluded that dispersal was an active process in response to environmental cues and that gene flow was affected by habitat differences and within-season variation in ecological processes. Third, we aimed to examine the extent, drivers, and fitness consequences of population structure within the two streams. To achieve this aim, we quantified the scale of structure, the effect of natal homing on structure, and the fitness outcomes of homing to, and dispersing from natal sites (Chapter Three). Both spatial and temporal genetic structure was evident within both streams, and this structure was partly explained by adults returning to the same place and at the same time as they were fertilized as eggs. In addition, phenotypes of body size and return timing were spatially segregated within the creeks. In one of the two creeks, adults returning to spawn near natal sites had greater fitness. Taken together, we concluded that these findings provided empirical evidence for how natal homing and heterogeneous habitat may lead to assortative mating systems and possible microgeographic adaptation on very small spatial and temporal scales. In other words, natal homing and dispersal within populations may result in genetic or phenotypic neighborhoods and affect fitness. Finally, we discuss the utility of these findings for predicting responses of natural populations to future environmental and anthropogenic changes such as harvest, climate change, and supportive breeding.
