Fish Physiology 

About: Fish Physiology is an academic journal published by Academic Press. The journal publishes majorly in the area(s): Gill & Zebrafish. It has an ISSN identifier of 1546-5098. Over the lifetime, 354 publications have been published receiving 37176 citations.

6 – Physiological Energetics

Abstract: Fish, like other living systems, must conform to the laws of thermodynamics. Fish gain matter and energy in food, and they lose absorbed matter and energy as a result of catabolism—which provides energy for maintenance and activity—and the elaboration of reproductive products. Physiological energetics, or animal bioenergetics, concerns the rates of energy expenditure, the losses and gains, and the efficiencies of energy transformation, as functional relations of the whole organism. The majority of such presentations commence with an energy-flow diagram indicating the main steps that the energy of food intake follows through the organism, and the paths of energy distribution. Each of these steps with their appropriate values is subject to quantitative change, depending on many biotic and abiotic factors. With the thought that the basis of these energy exchanges needs to be elaborated first, it was deemed more fitting to conclude with a quantitatively expressed flow diagram. An understanding of the physical, chemical, and biological basis on which the energetics is built, and the equivalents employed, constitutes the opening section of this chapter. Some necessary distinctions between mammalian and nonmammalian systems are made. An adequately nutritious diet is assumed; the basic source of fuel for the fire of life is solely derived from the food.

1 – The Effect of Environmental Factors on the Physiology of Fish

Abstract: The study of animal function is organized more or less under three heads, which in everyday language are, as applied to a machine, what it can do, how it works, and what makes it go. Insofar as fields of study can be classified in biology these divisions of the subject are ordinarily considered to be autecology, physiology, and biochemistry, with a great deal of individual taste governing the label any particular worker may choose for himself. The chapter discusses what fish can do in relation to their environment and therefore largely autecology. The chapter focuses on the action of the environment on metabolism and the effects of this action on the activity of the organism.

10 - Environmental Factors and Growth

Abstract: To understand how the many environmental factors influence growth, the basic rate functions should never be lost sight of, despite the general simplicity of growth measurements. As far as possible, the individual functions have been introduced in the chapter to provide some explanation of the response to environmental factors, without deviating from the major purpose of examining the recorded trends in the activity of growing. In relation to environmental effects, quite obviously growth cannot be studied without involving food consumption, even though the latter may not necessarily be measured. In this respect, growing—unlike such activities as swimming or respiring—is inseparably coupled with a powerful biotic factor, so that any abiotic factor is necessarily involved in some form of interaction between the two. Growth rate may either increase or decrease depending on the nature of the food × metabolism × temperature relation; on analysis it can be seen that the energy demand of elevated metabolic rate could have exceeded the gain from increased food uptake resulting in reduced growth rate. Furthermore, the act of growing necessarily alters size so that another important biotic factor continually changes with time. An understanding of these inherent involvements is necessary before any clear insight of the environmental relation to the growth process can be achieved.

11 – Growth Rates and Models

Abstract: Fish lengths have been measured in many different ways The differences arise from choosing different reference points near the anterior end and near the posterior end of the fish, and from using different methods of making the measurement Methods of making the measurement include using calipers; using a tape held along the curve of the body; laying the fish on a measuring board with the front end pressed against an upright piece; laying the fish on a board with a movable cross hair above it, attached to an indicator running along a scale In theory, any combination of reference points and methods might be used, but practice is considerably more restricted Some of the commoner combinations have special names; these are provided in the chapter, together with the reference points used In addition to these methodological differences, length varies with the condition of the fish—for example, whether it is alive, recently killed, after rigor mortis has set in, or at different intervals of time after preservation in formalin or alcohol

6 The Functional Morphology of Teleost Gonads

Abstract: Publisher Summary This chapter discusses the functional morphology of teleost gonads. Information presented in this chapter indicates that there are several processes of germ cell development, which are closely associated with changes in cellular activities of somatic cell elements. Recent studies on biochemical aspects of vitellogenesis in teleosts have shown that the hepatic and ovarian yolk proteins are similar to those of amphibian species. An in vitro method involving the separation of the follicular components has facilitated investigations of the detailed mechanism of the production of two major follicular steroid hormones. As a result of the usage of this technique, a two cell-type model involving thecal and granulosa cell layers has been proposed for the production of these two steroids for the first time in lower vertebrates. With further refinements this well characterized incubation procedure should provide an excellent system for studying the molecular basis of the mechanism of gonadotropin action on follicular steroidogenesis.