Determining environmental drivers of fish community structure along the coast of Maine

Jordaan, Adrian

Abstract is as follows: 'The work presented here was conceived to determine whether structure in marine communities could be related to multiple scaled environmental parameters, as seen in lake and stream systems. Four datasets collected from 2001 to 2005 were used. The datasets ranged from local scale tidepool and estuarine surveys, to more regional intertidal/subtidal surveys and conclude using a coast-wide trawl survey. Initially, a bootstrap program for running principal component analysis (PCA) was developed and tested for utility with additional information from Pearson correlation coefficients. The bootstrap-PC A program was capable of determining confidence limits for correlations amongst species. The results from analysis of the survey data suggest that factors influencing tidepool species assemblages were embedded in patterns of vertical zonation horizontal gradients in sediment type (wave energy). Patterns became more structured from spring to late summer and associations amongst tidepool variables shifted from physical-algal associations to invertebrate-fish associations. The analysis of an estuarine dataset suggested estuarine assemblages reflect an interaction between topography and the location of culverts as restrictions to tidal flow, and the resulting differences in the impoundment of water. Patterns offish assemblages, in a regional survey sampling the intertidal/subtidal zone, was structured and related to potential wave energy at two scales. The first scale was local potential wave energy which related a specific site and the morphology/behavior of species capable of occupying the space. The second scale was regional and related to patterns of immigration and extinction mediated by energy acting as a barrier to certain species. When a coast-wide trawl survey was analyzed, structure in fish populations along the coast correlated to oceanographic differences observed between eastern and western Maine. Temperature, longitude and their interaction were related to patterns in biological structure in the survey data. When seen as a whole, the results demonstrate that structure is present in the distribution of species at all scales. Fisheries management initiatives would do well to understand the scales that are relevant to their mandate.' Thesis is broken up into chapters as follows: INTRODUCTION SEASONAL USE OF THE INTERTIDAL ZONE BY FISH AND INVERTEBRATES IN WATERS ADJACENT TO ACADIA NATIONAL PARK: PATTERNS AND TRENDS DEFINING CLUSTERS AND VARIABLES USING BOOTSTRAPPING OF PRINCIPAL COMPONENT ANALYSIS: DEVELOPMENT OF TECHNIQUES FOR ANALYSIS OF ECOLOGICAL DATA PRINCIPAL COMPONENT ANALYSIS AND INTERTIDAL ECOLOGY: LINKING PHYSICAL AND BIOLOGICAL PROPERTIES PRINCIPAL COMPONENT ANALYSIS AND INTERTIDAL ESTUARINE ECOLOGY: WHAT ARE THE LIMITS OF ANALYSIS? COMMUNITIES OF FISH DEFINED ACROSS A WAVE ENERGY DIFFERENCES IN THE FISH COMMUNITY STRUCTURE BETWEEN EASTERN AND WESTERN INSHORE OF THE GULF OF MAINE DRIVERS OF COMMUNITY STRUCTURE IN THE GULF OF MAINE: APPLICATIONS AND CAVEATS --------------------- Lists species of fish caught during the tidepool survey (page 19) and estuarine survey (page 35) on Mount Desert Island and Schoodic Peninsula (combined data; not separable in tables, but some site specific data can be gleaned from other tables and figures). Tremendous amount of field work went into this thesis, but raw data is not presented in report.