The role of allelic variation in the management of fishes

The thesis consists of four papers that deal with the development of a biologically reasonable role for protein alleles in fisheries management. Paper 1: The need for an understanding of the biological properties of protein alleles is established by arguments that the neutral theory of alleliccvariation is an effective null hypothesis to the Fisher/Haldane/Wright definition of selection, but not a legitimate explanation for allelic variation in its own right. The literature demonstrating physiological differences between alleles in fish is reviewed. General biochemical and various ecological arguments are put forward to support the empirical evidence for significant physiological differences between alleles. The three main empirical arguments of neutral theorists, the segregational load argument, the molecular clock analogy, and the correlation between polymorphism and the molecular weight of proteins, have had a great influence on practical analysis and experimental design of fisheries management experiments in allele frequency. The validity of these empirical arguments is questioned. Statistical problems associated with the neutralist usage of allelic variation in fisheries management are briefly reviewed. Paper 2: Transferrin alleles are widely used in fisheries management as neutral markers. The biological role of transferrin alleles is reviewed and the effects of the biological properties and the statistical use of transferrin variants are discussed. Paper 3: The biological role of alleles requires some relationship between allelic variants and the parameters of fisheries management models before allelic variation can be assigned a practical role in fisheries management. Such a relationship is demonstrated between allelic genotypes at the phosphoglucomutase locus in liver and growth in the fish Cheilodactylus macropterus. Arguments are also presented for a significant change in allele frequency in this species due to fishing pressure. Paper 4: A biological role of alleles in fisheries management that is based on physiological differences between alleles may require an extensive understanding of the physiology and biochemistry of the fish before the allelic variation can be put to any practical use. Experimental data are presented to show that the metals Fe, Zn, P, Sr, and Na in the fish otolith reflect the ambient temperature. Thus an individual temperature life-history of a fish may be found in the otolith providing one, of the important experimental parameters necessary to understanding the biochemical and physiological role of allelic variants. The thesis concludes with a brief and general overview of fisheries management models and the reasons why the biological role of allelic variation is pertinent to these models.Arts, Faculty ofSociology, Department ofGraduat