Contribution of Physiology and Biochemistry to Progress in Aquaculture

Abstract

Physiological and biochemical methods and techniques are used to study biological processes at different levels of organization of living matter. Normal physiological processes of marine organisms caught in natural environment or maintained under constant external conditions have been studied in numerous scientific works. Nutrition, respiration, reproduction and metabolism for instance, are physiological functions more or less extensively known in algae, fishes, molluscs and crustaceans, among other phyla, generally depending on their economical interest. Less studied are the physiological variations characterizing these species under different external conditions, systematically fixed, one by one, or by groups, or under determined variations of these environmental factors. Ecophysiology provide considerable information on the ecological characteristics of the studied species in nature, where temperature, photophase, light intensity, salinity, etc…, vary simultaneously in a non-programmed manner. The effects and consequences of each of these factors considered individually must be evaluated and measured in order to ascertain the importance of each one in nature and for each physiological function. The scientific information obtained in these studies is easily made use of in aquaculture, especially with intensive techniques. The normal biochemical characteristics of marine organisms caught in natural environment or maintained under constant external conditions have sometimes been of interest for laboratories specialized in pure or physiological biochemistry. Some descriptive works in structural biochemistry, concerning the detailed composition of marine organisms, are available. The former vary in number and importance, depending on the different phyla. Enzymes characteristic of each physiological function, i.e. digestive enzymes in the nutritional function, and enzymes of intermediary metabolism for instance are much less known than in mammals, and sometimes not known at all in certain entire zoological groups. Biochemical variations of these species under systematically fixed or experimentally varying external conditions have been much less developed and are much less known, especially in marine organisms. This scientific area, which can be called ecobiochemistry, will provide a fundamental explanation of the physiological functions of aquatic species, especially those reared in aquaculture. The physiological and biochemical rhythmicity of these species internal or imposed, circadian, seasonal, annual, or depending on the molting cycles in arthropods, have to be studied in detail in order to enhance intensive aquaculture and automatization of the related techniques. The relationship between the variable physiology and biochemistry of the hosts and their parasites, where interesting results have recently been obtained, have to be developed in order to gain an understanding of the processes of infestation, the reciprocal complementarities of the hosts and the parasite, and to improve the prevention and treatment of the hosts. Such a scientific area could be called ecophysioparasitology. Similarly, ecophysiopathology deals with the internal and external conditions of disease apparition. The development of ecophysiology and ecobiochemistry needs interdisciplinary teams made up of marine biologists, physiologists and biochemists, working closely with specialists in aquaculture and development. © 1982, The Japanese Society of Fisheries Science. All rights reserved.