7 research outputs found
Mixed-Mode Surveys Compared with Single Mode Surveys: Trends in Responses and Methods to Improve Completion
This article reviews recent trends in modes of conducting surveys and presents results from a series of experiments comparing different approaches for collecting survey data and improving response rates in general population studies. The modes examined include the telephone, mail, and a mixed-mode method which combines mail with Web data collection. A series of studies were conducted by the Oregon State University Survey Research Center from 2006-2014 using probability samples of Oregon residents. Response rates and the percent of respondents completing the questionnaires by Web were compared. The results showed that response rates were increased by modifying the cover letter to emphasize the cost savings of an online response, adding a fifth contact, and limiting instructions for respondents. A mixed-mode approach, providing only a Web link, resulted in more respondents replying by Web as compared with individuals given an option of completing the questionnaire by Web or mail. The demographics of the respondents, as compared with the general population, varied across each mode
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Impacts of Multispecies Parasitism on Juvenile Coho Salmon (Oncorhynchus kisutch) in Oregon
We are studying the impacts of parasites on threatened stocks of Oregon coastal coho salmon (Oncorhynchus kisutch). In our previous studies, we have found high infections of digeneans and myxozoans in coho salmon parr from the lower main stem of West Fork Smith River (WFSR), Oregon. In contrast parr from tributaries of this river, and outmigrating smolts, harbor considerably less parasites. Thus, we have hypothesized that heavy parasite burdens in parr from this river are associated with poor overwintering survival. The objective of the current study was to ascertain the possible effects these parasites have on smolt fitness. We captured parr from the lower main stem and tributaries of WFSR and held them in the laboratory to evaluate performance endpoints of smolts with varying degrees of infection by three digeneans (Nanophyetus salmincola, Apophallus sp., and neascus) and one myxozoan (Myxobolus insidiosus). The parameters we assessed were weight, fork length, growth, swimming stamina, and gill Na+,K+36 -ATPase activity. We repeated our study on the subsequent year class and with hatchery reared coho salmon experimentally infected with N. salmincola. The most significant associations between parasites and these performance or fitness endpoints were observed in the heavily infected groups from both years. We found that all parasite species, except neascus, were negatively associated with fish fitness. This was corroborated for N. salmincola causing reduced growth with our experimental infection study. Parasites were most negatively associated with growth and size, and these parameters likely influenced the secondary findings with swimming stamina and ATPase activity levels.This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/aquaculture/Keywords: Parasites, Mixed infections, Wild coho salmon smolts, Threatened stocks, Fitness correlatesKeywords: Parasites, Mixed infections, Wild coho salmon smolts, Threatened stocks, Fitness correlate
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KentMichael.Microbiology.ImpactsMultispeciesParasitism.pdf
We are studying the impacts of parasites on threatened stocks of Oregon coastal coho
salmon (Oncorhynchus kisutch). In our previous studies, we have found high infections of
digeneans and myxozoans in coho salmon parr from the lower main stem of West Fork Smith
River (WFSR), Oregon. In contrast parr from tributaries of this river, and outmigrating smolts,
harbor considerably less parasites. Thus, we have hypothesized that heavy parasite burdens in
parr from this river are associated with poor overwintering survival. The objective of the current
study was to ascertain the possible effects these parasites have on smolt fitness. We captured parr
from the lower main stem and tributaries of WFSR and held them in the laboratory to evaluate
performance endpoints of smolts with varying degrees of infection by three digeneans
(Nanophyetus salmincola, Apophallus sp., and neascus) and one myxozoan (Myxobolus
insidiosus). The parameters we assessed were weight, fork length, growth, swimming stamina,
and gill Na+,K+36 -ATPase activity. We repeated our study on the subsequent year class and with
hatchery reared coho salmon experimentally infected with N. salmincola. The most significant
associations between parasites and these performance or fitness endpoints were observed in the
heavily infected groups from both years. We found that all parasite species, except neascus, were
negatively associated with fish fitness. This was corroborated for N. salmincola causing reduced
growth with our experimental infection study. Parasites were most negatively associated with
growth and size, and these parameters likely influenced the secondary findings with swimming
stamina and ATPase activity levels
Recommended from our members
KentMichaelMicrobiologyImpactsMultispeciesParasitismFullText.pdf
We are studying the impacts of parasites on threatened stocks of Oregon coastal coho
salmon (Oncorhynchus kisutch). In our previous studies, we have found high infections of
digeneans and myxozoans in coho salmon parr from the lower main stem of West Fork Smith
River (WFSR), Oregon. In contrast parr from tributaries of this river, and outmigrating smolts,
harbor considerably less parasites. Thus, we have hypothesized that heavy parasite burdens in
parr from this river are associated with poor overwintering survival. The objective of the current
study was to ascertain the possible effects these parasites have on smolt fitness. We captured parr
from the lower main stem and tributaries of WFSR and held them in the laboratory to evaluate
performance endpoints of smolts with varying degrees of infection by three digeneans
(Nanophyetus salmincola, Apophallus sp., and neascus) and one myxozoan (Myxobolus
insidiosus). The parameters we assessed were weight, fork length, growth, swimming stamina,
and gill Na+,K+36 -ATPase activity. We repeated our study on the subsequent year class and with
hatchery reared coho salmon experimentally infected with N. salmincola. The most significant
associations between parasites and these performance or fitness endpoints were observed in the
heavily infected groups from both years. We found that all parasite species, except neascus, were
negatively associated with fish fitness. This was corroborated for N. salmincola causing reduced
growth with our experimental infection study. Parasites were most negatively associated with
growth and size, and these parameters likely influenced the secondary findings with swimming
stamina and ATPase activity levels