| dc.contributor.author | Marshall, Catherine Tara. | en_US |
| dc.date.accessioned | 2014-10-21T12:36:51Z | |
| dc.date.available | 1995 | |
| dc.date.issued | 1995 | en_US |
| dc.identifier.other | AAINN05282 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10222/55064 | |
| dc.description | The interrelationship among stock abundance, spatial distribution, growth and recruitment for haddock (Melanogrammus aeglefinus) on the southwestern Scotian Shelf was assessed using data from standard bottom trawl surveys conducted by Canada (1970-92) and the United States (1963-86). Recent studies using survey data to describe interannual variation in the the spatial distribution of marine fish stocks have yielded contradictory results. Several sources of imprecision and bias in these distributional indices were identified which limited their utility for describing the geographic response of groundfish stocks to changes in total abundance. An improved modelling approach was developed which described the statistical relationship between total abundance-at-age and local density of juvenile haddock for sub-areas of the stock range. Systematic variation among sub-areas in parameter estimates of the model was consistent with density-dependent habitat selection: juvenile haddock responded to increases in total abundance-at-age by increasing their local density in sub-areas where they were absent or scarce when abundance was low. A distinct spatial gradient in growth of haddock was also evident with individuals resident in the Bay of Fundy being larger than their counterparts on the southwestern Scotian Shelf. This difference necessitated partitioning the survey data into two subcomponents for the analysis of interannual variation in growth. Both stock abundance and bottom water temperature influenced interannual variation in growth of haddock, however, their relative importance depended on the time period, subcomponent, and age-classes considered. Growth of juveniles on the southwestern Scotian Shelf varied inversely with stock abundance. Body size characteristics of adult haddock on the southwestern Scotian Shelf were positively correlated with recruitment which suggests that interannual variation in population fecundity may be an important source of recruitment variation. A simulation example suggested that estimates of spawning stock biomass are not proportional to population fecundity which could explain the widespread lack of correlation between spawning stock biomass and recruitment. | en_US |
| dc.description | Thesis (Ph.D.)--Dalhousie University (Canada), 1995. | 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 | Agriculture, Fisheries and Aquaculture. | en_US |
| dc.title | Biological and geographical limits on the production dynamics of haddock (Melanogrammus aeglefinus) on the southwestern Scotian Shelf. | en_US |
| dc.type | text | en_US |
| dc.contributor.degree | Ph.D. | en_US |
