Growth of Juvenile Coho Salmon in Natural and Created Estuarine Habitats PDF Download

Author: J. A. Miller
Publisher:
ISBN:
Category : Coho salmon
Languages : en
Pages : 80

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Author: Jessica A. Miller
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 168

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Author: Paul M. Iwanaga
Publisher:
ISBN:
Category : Fishes
Languages : en
Pages : 52

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Author: Shari K. Witmore
Publisher:
ISBN:
Category : Coho salmon
Languages : en
Pages : 150

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Retention rate was positively correlated with average maximum depth; however the summer retention rate of juvenile salmon at the sites was not correlated with salmon growth at the sites. I observed three seasonal movement patterns of juvenile coho salmon: spring redistribution of fry; fall redistribution associated with initial high flows, and outmigration of smolts during the following spring. A diurnal movement pattern was also detected at the mouths of Tom Martin Creek and Caltrans Pond in which juvenile coho salmon left the study site in the evening and returned in the early morning. This exploratory study showed that not only do juvenile coho salmon in the mid-Klamath display several different migratory patterns; choosing different types of off-channel habitats to rear, but the growth and retention rates of those fish depend on complex and site specific characteristics rather than type of habitat.

Author: Adam D. Weybright
Publisher:
ISBN:
Category : Coho salmon
Languages : en
Pages : 110

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Juvenile salmonids display highly variable spatial and temporal movement patterns that are influenced by density dependent (e.g., competition, predation) and density independent (e.g., genetics, stream discharge, physical habitat conditions) factors. The effects of these factors differ with fish life history stage, but will ultimately affect how salmonids utilize freshwater nursery habitats and influence their size at smolting. Although juvenile coho salmon (Oncorhynchus kisutch) (Walbaum 1792) movement patterns and their relationships with body mass have been previously examined, the temporal scale considered in most studies has been within individual seasonal periods. In this study, we monitored the movement of PIT tagged juvenile coho salmon throughout the period of freshwater residence in an entire southern Oregon coastal basin to identify the prevalent sedentary and mobile strategies these fish may adopt and to examine possible relationships between those strategies and fish body mass, growth and survival. Specific objectives include: 1) to describe juvenile coho salmon movement strategies and patterns during the freshwater residence period; 2) to determine the relative proportions of juvenile coho salmon that exhibit each movement strategy; 3) to establish whether juvenile coho salmon body mass and growth rates are related with a set of habitat variables recorded during this study; 4) to determine whether coho salmon body mass or growth rates are related to movement strategy; and 5) to evaluate whether winter survival of juvenile coho salmon is associated with movement strategy. Results revealed seasonally and spatially variable movement. More than half of coho salmon tracked throughout the period of freshwater residence exhibited movement behavior that differed between summer and winter seasons. Within seasonal periods, coho salmon in tidally affected reaches exhibited greater prevalence of mobile behavior relative to those in riverine reaches. Regression analysis indicated coho biomass density, habitat unit structural complexity and size at tagging were important in predicting summer growth of coho salmon. Juvenile coho salmon that were mobile during summer were either larger or no different in body mass in early summer relative to fish that exhibited sedentary behavior. Similarly, no consistent differences were observed between sedentary and mobile coho salmon in regards to summer growth. Coho salmon that were sedentary in summer and winter experienced higher apparent winter survival than mobile fish in each season, though the reach in which an individual resided at the start of winter appeared to also affect survival. Coho salmon residing in the tide gate reservoir reach and mainstem headwater reaches experienced greatest apparent winter survival. These results indicate that juvenile coho salmon movement within a stream basin is spatially and temporally variable and that mobility does not necessarily indicate inferior competitive ability. In a broader context, variable movement patterns reflect the capacity for plastic behavior in salmonids and this research demonstrates the importance of maintaining seasonally diverse freshwater and estuarine nursery habitats for juvenile fish.

Author: Kailan F. Mackereth
Publisher:
ISBN:
Category : Coho salmon
Languages : en
Pages : 44

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Loss of lowland estuarine and freshwater off-channel habitats along the Pacific Northwest coast has contributed to the decline of salmonid populations. These habitats serve as nursery grounds for juvenile salmonids providing them with food, winter shelter, and a transition zone between freshwater and saltwater. Lowland areas have undergone anthropogenic alterations (e.g., installation of tide gates, construction of dikes, channelization) to increase the net area of land suitable for agriculture and development resulting in watershed fragmentation and reduction in the amount of habitats with high intrinsic potential to support populations of juvenile salmonids. Until recent years, sub-yearling coho salmon found in lowland riverine habitats and estuarine marshes were assumed to have been displaced from optimal upland reaches by competition and high water discharge. Recent studies have concluded that early estuarine migrant behavior is volitional and these fish return as 20-40% of the spawning population, but there are few studies that delve into the capacity of estuarine habitat to support early estuarine life history strategies in systems heavily altered by human practices. This study documented differences in diet and condition factor (K) between sub-yearling and yearling coho salmon foraging concurrently in brackish or freshwater lowland habitat of the upper estuarine intertidal zone. Fish stomach contents were sampled by means of gastric lavage in three coastal lowland creeks in Coos Bay on the southern Oregon coast. Prey found in the samples were sorted, counted, identified, and dried to obtain dry weight biomass. Condition factor (K) and total dry weight prey biomass of fishes were not different between brackish and freshwater habitat; however, non-metric multidimensional scaling indicated that prey composition was substantially different between habitat and age class. These findings suggest that early migrating sub-yearlings and yearling smolts diverge in their diets whether they occupy the same or different habitats in the stream to estuary transition zone. Insects were important prey within the diets of yearling and sub-yearling freshwater foragers and sub-yearling brackish water foragers while crustaceans were important in the diets of yearling brackish water foragers. Future research exploring prey abundance and availability in relation to prey selected by juvenile coho salmon would denote habitat foraging quality and habitat exploitation by early estuarine migrants. Expanding this research to contrast natural intertidal habitats with those regulated by tide gates would be beneficial towards understanding the impact different styles of tide gates have on biotic communities and hydrological attributes (e.g., flow, chemistry, temperature, tidal exchange). Identification of factors that influence habitat selection in the stream-estuary ecotone by alternative early life history strategies of juvenile coho salmon is essential towards enhancing genetic diversity thereby strengthening the resiliency of the population.

Author: Thomas P. Quinn
Publisher: UBC Press
ISBN: 0774842431
Category : Nature
Languages : en
Pages : 392

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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: Michelle R. Krall
Publisher:
ISBN:
Category : Coho salmon
Languages : en
Pages : 80

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Substantial investment has been directed toward construction of off-channel ponds in the middle Klamath River basin to benefit Coho Salmon populations. Previous research showed that abundance, retention, and growth of juvenile Coho Salmon varied across sites but were not consistently different between constructed ponds and natural habitats; instead, variation was attributed to individual site characteristics. However, the characteristics responsible for these differences are not clear. In this exploratory study, I investigated the effect of accessibility on juvenile Coho Salmon abundance within nine constructed ponds. I also assessed whether habitat conditions, Coho Salmon density, and food availability within the ponds could predict abundance, retention, and growth of Coho Salmon. Few strong relationships were found between characteristics of ponds and the response variables. Despite potentially stressful conditions at some sites, Coho Salmon occupied most ponds through the summer, suggesting that they provide suitable rearing habitats. Lack of accessibility throughout the year had potentially important effects on the survival and life history of individuals trapped in constructed ponds. Retention rates were strongly correlated with zooplankton availability, while Coho Salmon density and available benthic prey displayed little correlation with retention. While growth rate differed among ponds; while measures of prey availability did not explain variation in growth rate, growth rate was negatively correlated with Coho Salmon density in the ponds. Constructed off-channel ponds serve as important rearing habitat for Coho Salmon and an increased understanding of their role in Coho Salmon rearing and production is necessary.

Author: Paul M. Iwanaga
Publisher:
ISBN:
Category : Fishes
Languages : en
Pages : 35

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Author: Gregory R. McMurray
Publisher:
ISBN:
Category : Coastal ecology
Languages : en
Pages : 380

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