Aspects of the biology and local distribution of sea stars inhabiting a sloped, rocky bottom in Logy Bay, Newfoundland

Emerson, Ian Paul (1973) Aspects of the biology and local distribution of sea stars inhabiting a sloped, rocky bottom in Logy Bay, Newfoundland. Masters thesis, Memorial University of Newfoundland.

[English] PDF (Migrated (PDF/A Conversion) from original format: (application/pdf)) - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (57MB) [English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. (Original Version)

Abstract

The spatial and temporal distribution of five species of asteroids were examined over a one year sampling programme by means of a series of photographs taken weekly along a set transect line extending perpendicularly down a sloped sublittoral rocky bottom, in Logy Bay, Newfoundland. Estimates of the abundance and distribution of three species of asteroids inhabiting a more gently sloped sublittoral plateau surmounting this underwater cliff were also determined using a variety of quantitative and qualitative sampling techniques. -- The results of systematic studies of selected physical, chemical, and biological characteristics of these habitats are presented. Such characteristics include depth, slope, relative irradiance, water temperature, dissolved oxygen concentration, conductivity, and predator and prey abundance and distribution. -- Specific studies relating to the interaction of sea stars with their environment (i.e. feeding, light preference, pull capacity, and interspecific and intraspecific behaviour), undertaken to elucidate factors affecting sea star distribution, are also presented. -- A presentation of the effects of other specific biological activities on local distribution patterns, such as migration and movement, reproduction and growth is also given. -- In the general discussion, a hypothetical model for considering interactions between a species and its environment that affect population dynamics and local distribution is presented. The model is then utilized in an analysis of locally observed asteroid distribution patterns in the study area. From this analysis it is concluded that the distribution or occurrence of water disturbance, prey, predators, and competitors are the major factors affecting the abundance-distribution patterns of the sea stars in the study area. A wider range of interactions between a given species and its environment may be of secondary importance in this relationship.

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