Population dynamics and life history characteristics of boreal appendicularian species in Conception Bay, Newfoundland, Canada
The primary goal of this study was to investigate the population dynamics and life history traits of boreal appendicularian species in Conception Bay, Newfoundland. Specific questions were; (1) What are the optimum environmental conditions for appendicularian species? (2) What are their generation t...
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| Format: | Thesis |
| Language: | English |
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Memorial University of Newfoundland
2008
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| Online Access: | https://research.library.mun.ca/8872/ https://research.library.mun.ca/8872/1/Choe_Nami2.pdf |
| Summary: | The primary goal of this study was to investigate the population dynamics and life history traits of boreal appendicularian species in Conception Bay, Newfoundland. Specific questions were; (1) What are the optimum environmental conditions for appendicularian species? (2) What are their generation time, and growth and secondary production rates? (3) How do length-at-age, age-at-maturity and fecundity vary under seasonally fluctuating environmental conditions and how do these demographic parameters relate to population growth rate? In order to study life history and demographic traits of naturally occurring populations of appendicularians, it was necessary to develop an in situ method of age determination. -- The temporal and spatial niche of appendicularian species is defined primarily by temperature and salinity in which Oikopleura vanhoeffeni is a cryophilic, stenothermal and stenohaline species, Fritillaria borealis typica is eurythermal and euryhaline and Oikopleura labradoriensis is mesothermal and mesohaline. Throughout the year, more than 70 % of the individuals of each species were present above 100 m, indicating that a majority of them experienced seasonal variation in abiotic and biotic factors. -- The presence of lipofuscin in the brain tissue, growth rings on the statolith and statolith diameter were explored as age indicators for appendicularians. The results indicated that statolith diameter was a feasible and reliable age indicator. A laboratory study of statolith diameter and somatic growth in O. vanhoeffeni showed that variability in statolith diameter-at-age was substantially lower than that in trunk length-at-age, and that variability in statolith-at-age remained constant with age whereas variability in trunk length-at-age increased with age, suggesting that statolith diameter should be a better in situ indicator of age than body size. Using statolith diameter as a proxy for age, trunk length-at-age of O. vanhoeffeni and O. labradoriensis in Conception Bay varied seasonally depending on food ... |
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