The Sultanate of Oman has 1700 km of coastline extending from the Arabian Gulf
south to the Arabian Sea. The demersal fish distributions and assemblages have not previously
been well defined. In winter, variations in the oceanography of the area are minimal. In
summer, however, the Arabian Sea is strongly influenced by the southwest monsoon.
For this study the continental shelf off Oman was divided into eight regional areas and
research trawl data on the distribution of demersal fish assemblages was studied using two
forms of multivariate statistical analysis: two-way indicator species analysis and detrended
correspondence analysis. The study was carried out to examine the influence on the species
assemblages of geographical zonation, seasonal variation, and factors such as depth, time of
day, and distance from untrawlable ground. There was seasonal variation in the fish
assemblages and this variation was greatly influenced by the summer monsoon. Within each
regional area depth appeared to be the major factor determining species distribution.
In addition to the multivariate analyses, univariate techniques were applied to the
catch rate data for forty commercial species to study in detail the influence of time of day and
distance from untrawlable ground, factors which could potentially influence stock assessment
estimates of fish biomass. Because the data were highly unbalanced, they were analyzed using
General Linear Model with five factors, two continuous variables, and ten interaction terms
to examine variation in the log-transformed catch rates. The factors time of day and distance
from untrawlable ground, in combination with other factors, had significant effects on the
catch rates for half of the species. / Graduation date: 1995
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/35315 |
| Date | 29 November 1994 |
| Creators | Ambusaidi, Hilal Saud |
| Contributors | Sampson, David B. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
Page generated in 0.0026 seconds