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Full-Text Articles in Physical Sciences and Mathematics
Modeling Oyster Populations Ii. Adult Size And Reproductive Effort, E. E. Hofmann, J. M. Klinck, E. N. Powell, S. Boyles, M. Ellis
Modeling Oyster Populations Ii. Adult Size And Reproductive Effort, E. E. Hofmann, J. M. Klinck, E. N. Powell, S. Boyles, M. Ellis
CCPO Publications
A time-dependent model of energy flow in post-settlement oyster populations is used to examine the factors that influence adult size and reproductive effort in a particular habitat, Galveston Bay, Texas, and in habitats that extend from Laguna Madre, Texas to Chesapeake Bay. The simulated populations show that adult size and reproductive effort are determined by the allocation of net production to somatic or reproductive tissue development and the rate of food acquisition, both of which are temperature dependent. For similar food conditions, increased temperature reduces the allocation of net production to somatic tissue and increases the rate of food acquisition. …
Modeling Oyster Populations. Iv. Rates Of Mortality, Population Crashes, And Management, E. N. Powell, J. M. Klinck, E. E. Hofmann, S. M. Ray
Modeling Oyster Populations. Iv. Rates Of Mortality, Population Crashes, And Management, E. N. Powell, J. M. Klinck, E. E. Hofmann, S. M. Ray
CCPO Publications
A time-dependent energy-flow model was used to examine how mortality affects oyster populations over the latitudinal gradient from Galveston Bay, Texas, to Chesapeake Bay, Virginia. Simulations using different mortality rates showed that mortality is required for market-site oysters to be a component of the population's size-frequency distribution; otherwise a population of stunted individuals results. As mortality extends into the juvenile sizes, the population's size frequency shifts toward the larger sizes. In many cases adults increase despite a decrease in overall population abundance. Simulations, in which the timing of mortality varied, showed that oyster populations are more susceptible to population declines …
Evaluation Of Implanted Radio Transmitters In Pheasant Chicks, Dean E. Ewing, William R. Clark, Paul A. Vohls
Evaluation Of Implanted Radio Transmitters In Pheasant Chicks, Dean E. Ewing, William R. Clark, Paul A. Vohls
Journal of the Iowa Academy of Science: JIAS
We studied game-farm pheasant (Phasianus colchicus Linneaus) chicks implanted with miniature transmitters to determine if surgery and implantation affected growth, behavior, or survival. Transmitters (weighing 1.2 g) were implanted subcutaneously in the interscapular region in day-old chicks. In Experiment 1, biological effects on chicks with transmitters implanted were compared with data from a control group. In Experiment 2, the effects of anesthesia only, anesthesia with an implanted transmitter, and implanted transmitter only were compared with a control. We measured responses of weight gain, survival, and pecking behavior in each experiment. In Experiment 1, we found no significant differences in weight …
Modeling Daily Production Of Aquatic Macrophytes From Irradiance Measurements: A Comparative Analysis, Richard C. Zimmerman, Alejandro C. Pasini, Randall S. Alberte
Modeling Daily Production Of Aquatic Macrophytes From Irradiance Measurements: A Comparative Analysis, Richard C. Zimmerman, Alejandro C. Pasini, Randall S. Alberte
OES Faculty Publications
The importance of submerged aquatic macrophytes to coastal ecosystems has generated a need for knowledge of minimum light levels that will support the maintenance and restoration of healthy populations. Our goals were (1) to evaluate the sensitivity to natural, non-sinusoidal fluctuations in irradiance I of analytical integration techniques for calculating daily carbon gain, (2) to evaluate the Hsat (the daily period of I-saturated photosynthesis) model of daily production relative to models based on instantaneous photosynthesis vs irradiance (P vs I) and (3) to provide some guidance for the temporal density of irradiance data required for accurate estimation of …
A Comparison Of A Validated Otolith Method To Age Weakfish, Cynoscion Regalis, With The Traditional Scale Method, Susan K. Lowerre-Barbieri, Mark E. Chittenden Jr., Cynthia M. Jones
A Comparison Of A Validated Otolith Method To Age Weakfish, Cynoscion Regalis, With The Traditional Scale Method, Susan K. Lowerre-Barbieri, Mark E. Chittenden Jr., Cynthia M. Jones
OES Faculty Publications
Otoliths, scales, dorsal spines, and pectoral-fin rays were compared to ascertain the best hardpart for determining the age of weakfish, Cynoscion regalis. Each showed concentric marks, which could be interpreted as annuli. Sectioned otoliths, however, consistently showed the clearest marks, had 100% agreement between and within readers, and were validated by the marginal increment method for ages 1-5. This validated method of ageing weakfish was then compared with the traditionally used scale method. The scale method was less precise, as demonstrated by lower percent agreement, and generally assigned younger ages for fish older than age 6 (as determined by …