| dc.contributor.author | Tupper, Mark. | en_US |
| dc.date.accessioned | 2014-10-21T12:35:51Z | |
| dc.date.available | 1994 | |
| dc.date.issued | 1994 | en_US |
| dc.identifier.other | AAINN05173 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55024 | |
| dc.description | This study examines the role of energy as a limiting resource in the regulation of demersal juvenile fish populations. In situ time and energy budgets of daily activities were constructed for cunner (Tautogolabrus adspersus), a common temperate reef fish, in St. Margarets Bay, NS. Maximum O$\sb2$ consumption of each component of the daily energy budget (resting, foraging and shelter site defense) can sum to a value much higher than the maximum O$\sb2$ uptake. Cunner must therefore allocate energy to each component so that the scope for activity is not exceeded. Under natural conditions, cunner operated at a low proportion of their scope for activity, although a peak of activity late in the day substantially reduced surplus power. Competition for shelter sites was an important component of the energy budget of cunner and could expend almost the entire scope for activity when shelter was limiting. This greatly reduced the surplus energy for growth, as evidenced by the strong density-dependence of growth measured in populations where density had been manipulated by transplanting fish among isolated reefs. High densities of conspecifics also reduced post-settlement survival, although density had no effect on settlement rate. Thus it appears that post-settlement processes involving resource (energy) limitation are more important than settlement variation in regulating populations or cunner in St. Margarets Bay. | en_US |
| dc.description | No particular energetic advantage was offered by any of 4 available habitat types (reef, cobble, seagrass, sand), and cunner showed no evidence of microhabitat selection at or following settlement. Instead, differential predation pressure resulted in variation of recruitment success among habitats. Predators were less successful at capturing newly settled cunner in topographically complex habitats (reef and cobble), and survival was highest in those habitats. Growth rates of 0+ cunner also differed among habitats but was highest in seagrass beds. Thus, 0+ cunner face trade-offs between energy gain (growth) and predation mortality. Mortality of cunner was size-dependent and growth rates of individual fish may therefore be good predictors of their potential survival. Individual growth rates were correlated with the scope for activity remaining after the metabolic costs of foraging were met. Thus, genetic techniques that focus on the heritability of growth processes might be useful predictors of survival of juvenile demersal fishes. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1994. | en_US |
| dc.language | eng | en_US |
| dc.publisher | Dalhousie University | en_US |
| dc.publisher | | en_US |
| dc.subject | Biology, Ecology. | en_US |
| dc.subject | Biology, Oceanography. | en_US |
| dc.subject | Biology, Zoology. | en_US |
| dc.title | Settlement and post-settlement processes in the population regulation of a temperate reef fish: The role of energy. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
