Geographic Variation in Timing of Fry Emergence and Smolt Migration of Coho Salmon (Oncorhynchus Kisutch) PDF Download
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Author: Brian C. Spence Publisher: ISBN: Category : Coho salmon Languages : en Pages : 402
Book Description
The timing of two events in the early life history of coho salmon--emergence from the gravel and entry into the ocean--is presumed to have evolved to ensure maximum survival during these transition periods. Anthropogenic disturbances may disrupt the timing of these events to the detriment of salmon populations. Multivariate analyses were used to examine regional patterns in downstream migration in relation to environmental variation for 50 smolt populations located between central California and southern Alaska. Significant latitudinal gradients were observed in the timing of the peak of migration, duration of migration, and degree of interannual variation in the peak of migration. Smolt migrations of northern populations generally occurred later in the spring, were shorter in duration, and exhibited lower interannual variability in their timing than did those of southern populations. Some variability in these patterns was associated with watershed characteristics (e.g., elevation, distance from ocean); however, latitudinal patterns transcended this variability and may reflect adaptation to differences in temporal "windows of opportunity" in the ocean environments into which smolts enter. Logistic regression models were used to model within- and between-year variation in probability of smolts migrating during 2-d intervals from four streams in Alaska, British Columbia, and Oregon as a function of time interval, lunar periodicity, temperature (absolute, change, cumulative degree days), and streamflow (absolute, change). Migration probability was positively associated with time, temperature, and change in flow, and negatively associated with absolute flow for at least four of the five data sets examined (P
Author: Brian C. Spence Publisher: ISBN: Category : Coho salmon Languages : en Pages : 402
Book Description
The timing of two events in the early life history of coho salmon--emergence from the gravel and entry into the ocean--is presumed to have evolved to ensure maximum survival during these transition periods. Anthropogenic disturbances may disrupt the timing of these events to the detriment of salmon populations. Multivariate analyses were used to examine regional patterns in downstream migration in relation to environmental variation for 50 smolt populations located between central California and southern Alaska. Significant latitudinal gradients were observed in the timing of the peak of migration, duration of migration, and degree of interannual variation in the peak of migration. Smolt migrations of northern populations generally occurred later in the spring, were shorter in duration, and exhibited lower interannual variability in their timing than did those of southern populations. Some variability in these patterns was associated with watershed characteristics (e.g., elevation, distance from ocean); however, latitudinal patterns transcended this variability and may reflect adaptation to differences in temporal "windows of opportunity" in the ocean environments into which smolts enter. Logistic regression models were used to model within- and between-year variation in probability of smolts migrating during 2-d intervals from four streams in Alaska, British Columbia, and Oregon as a function of time interval, lunar periodicity, temperature (absolute, change, cumulative degree days), and streamflow (absolute, change). Migration probability was positively associated with time, temperature, and change in flow, and negatively associated with absolute flow for at least four of the five data sets examined (P
Author: Thomas P. Quinn Publisher: University of Washington Press ISBN: 0295743344 Category : Nature Languages : en Pages : 562
Book Description
The Behavior and Ecology of Pacific Salmon and Trout combines in-depth scientific information with outstanding photographs and original artwork to fully describe the fish species critical to the Pacific Rim. This completely revised and updated edition covers all aspects of the life cycle of these remarkable fish in the Pacific: homing migration from the open ocean through coastal waters and up rivers to their breeding grounds; courtship and reproduction; the lives of juvenile salmon and trout in rivers and lakes; migration to the sea; the structure of fish populations; and the importance of fish carcasses to the ecosystem. The book also includes information on salmon and trout transplanted outside their ranges. Fisheries expert Thomas P. Quinn writes with clarity and enthusiasm to interest a wide range of readers, including biologists, anglers, and naturalists. He provides the most current science available as well as perspectives on the past, present, and future of Pacific salmon and trout. In this edition: Over 100 beautiful color photographs of salmon and troutUpdated information on all aspects of the salmon and trout life cycleExpanded coverage of trout
Author: Rachel LovellFord Publisher: ISBN: Category : Coho salmon Languages : en Pages : 146
Book Description
Coho salmon (Oncorhynchus kisutch) migration and spawning are unique components of the salmon life cycle because they require synchrony of behavior with other individuals as well as with acceptable fluvial conditions. As with other organisms that exhibit group mating behavior, it is likely that environmental cues trigger coho salmon movement to spawning grounds. These cues may also provide usable habitat for migration and spawning. River discharge, temperature, and length of day have long been assumed to be the environmental cues which trigger migration and spawning of coho salmon as coho return within the same season each year to spawn. Hatchery studies have also shown that the timing of reproductive behavior is heritable. If this heritability is determined by the fluvial conditions of the spawning grounds, then a predictable relationship should exist between reproductive behavior and the hydrologic and thermal regimes. Surprisingly, no defensible correlations between discharge thresholds and spawning or migrating activity have been identified for naturally reproducing coho salmon. Thermal, velocity, and depth limitations have been identified for coho salmon, but these values have not been examined in combination or within the context of a hydrologic and thermal regime. This study compares interannual patterns in the timing of coho mid-river migration in the North Umqua (180 km up river from the estuary) and the initiation of spawn timing in the Smith River basins (Oregon) with river discharge and water temperature data to ascertain whether these behaviors are driven by fluvial conditions. Additionally, we used this data to identify the window over which most migration and spawning takes place in our test systems. On the North Umpqua, coho salmon mid-river migration initiated (first 5% of migrants) after summer peak temperatures and following a threshold average daily temperature of 18° C, but before fall storm events occurred. In most years, approximately 75% of the migrating coho salmon have moved past the Winchester Dam before fall storms initiated and when discharge remained less than the 11 year average for the month of November, more similar to summer than winter flow levels. Additionally, characteristic lengths and numbers of peaks within the distribution of annual migrations were attributable to the generational cohort that the migration belonged to despite the similarity in population size across all years. These patterns in the distribution of generational cohorts suggest an inherited timing response as well as highlight cohorts which may contain diminished sub-populations. The initiation of coho salmon spawning appears limited both by a thermal threshold of 12° C in all basins, as well as by a minimal discharge threshold, which is unique to each stream. Continued spawning activity occurs as discharge remains elevated from fall levels. It is also notable that there was no statistical difference in the date of the initiation of spawning within each basin in a given year or across years at a given site. Together, these studies highlight the important role that the coho salmon genome plays in reproductive timing as well as the ways that fluvial thresholds limit reproductive behavior in time. Coho have survived because of their genome has been resilient when faced with environmental change. Future work should consider variability in fluvial conditions relative to coho salmon phenotypic plasticity over time. Coho salmon phenotypic plasticity will determine whether the rate of change of the hydrologic and thermal regimes important to coho salmon survival outpaces the coho's ability to adapt. This study contributed to this future work by establishing baseline relationships between the behavior of a threatened species and measurable environmental thresholds.
Author: Andrew P. Hendry Publisher: Springer Science & Business Media ISBN: 9401005850 Category : Science Languages : en Pages : 528
Book Description
From guppies to Galapagos finches and from adaptive landscapes to haldanes, this compilation of contributed works provides reviews, perspectives, theoretical models, statistical developments, and empirical demonstrations exploring the tempo and mode of microevolution on contemporary to geological time scales. New developments, and reviews, of classic and novel empirical systems demonstrate the strength and diversity of evolutionary processes producing biodiversity within species. Perspectives and theoretical insights expand these empirical observations to explore patterns and mechanisms of microevolution, methods for its quantification, and implications for the evolution of biodiversity on other scales. This diverse assemblage of manuscripts is aimed at professionals, graduate students, and advanced undergraduates who desire a timely synthesis of current knowledge, an illustration of exciting new directions, and a springboard for future investigations in the study of microevolution in the wild.
Author: Robert Bryan Lindsay Publisher: ISBN: Category : Coho salmon Languages : en Pages : 82
Book Description
Large numbers of coho salmon (Oncorhynehus kisutch) fry move downstream shortly after emergence from the gravel in many spawning tributaries. In three small coastal streams of Oregon about eight times more juveniles leave the tributaries as newly emerged fry than as smolts one year later. Because these early emigrants comprise such a large proportion of the total out-migration of juvenile coho from these streams, a study was initiated to determine their distribution and survival and to evaluate their contribution, if any, to the spawning escapements. In spring 1972, all emigrating coho fry were marked with ventral finclips as they entered fish traps located near the mouths of the three natal streams. Coho fry were later examined for ventral marks in July and September at 19 sampling stations in downstream areas. Emigrants generally dispersed downstream after being marked, although some upstream movement occurred once they entered-larger tributaries. A few moved as far as 9.7 km downstream from the fish traps. Few, if any, migrated directly to saltwater. The proportion of emigrants in samples of coho fry was highest directly below the fish traps and decreased farther downstream. Emigrant fry were not evenly distributed-in downstream areas. About 7% of the emigrants survived to September. Survival rates of emigrant fry and of fry In downstream areas that had not emigrated from the study streams (residents)were similar from July to September, being 43% and 46%, respectively. The survival of coho that remained above the traps was 78% for the same time period. The evidence suggests emigrants were as competitive as residents in downstream areas, but that environments downstream were more adverse than those farther upstream. Eight adult and jack coho salmon that had been marked as emigrating fry in spring 1969, returned to spawn in the natal streams in 1970-71 and 1971-72. They represented a known return of about 0.1% of the emigrants. Emigrant fry probably contributed to spawning escapements in downstream areas as well, but contributions to these areas could not be directly evaluated.
Author: Brian C. Spence
Author: Brian C. Spence
Author: Thomas P. Quinn
Author: Gregory R. McMurray
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Author: 
Author: Rachel LovellFord
Author: Andrew P. Hendry
Author: California. Department of Fish and Game
Author: Robert Bryan Lindsay
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