Showing papers in "Fish Physiology in 2005"
TL;DR: In this paper, the authors focus on recent experimental hydrodynamic data on undulatory locomotion in fishes, and provide a general description of the major theoretical model of undulatory propulsion.
Abstract: Publisher Summary The chapter focuses on recent experimental hydrodynamic data on undulatory locomotion in fishes, and provides a general description of the major theoretical model of undulatory propulsion. The investigations of fish propulsion have had to infer hydrodynamic function from kinematics and theoretical models. Biologists and engineers interested in how fishes interact with their fluid environment have had no quantitative way to visualize this interaction, despite the critical importance of understanding fluid flow patterns produced by swimming fishes for testing theoretical models and for understanding the hydrodynamic effects of different body and fin designs. The combination of high‐resolution high‐speed video systems, high-powered continuous wave lasers, and an image analysis technique called digital particle image velocimetry (DPIV), developed over the past decade, has permitted the direct visualization of water flow over the surface and in the wake of swimming fishes. These data have provided a wealth of new information on the fluid flows generated by the body, tail, and fins of freely swimming fishes, and represent a significant new arena of investigation.
217 citations
187 citations
TL;DR: This chapter discusses freezing avoidance of polar fish by means of antifreeze proteins (APs), with particular attention to how antifREEzes interface with the anatomy and physiology of the fish, and in relation to the freezing marine environments they inhabit.
Abstract: Publisher Summary Temperature is one of the key physical environmental factors, governing the distributions of living organisms. This chapter discusses freezing avoidance of polar fishes by means of antifreeze proteins (APs), with particular attention to how antifreezes interface with the anatomy and physiology of the fish, and in relation to the freezing marine environments they inhabit. Since the discovery of the first fish antifreeze in the Antarctic fish, significant advances have been made in the identification and characterization of new types of AP in other fish taxa and in the mechanism of action of the APs. In contrast, understanding the in vivo role of APs in freeze avoidance of the fish in their natural environments has lagged considerably.
149 citations
TL;DR: The relationship between fish form and swimming performance go back several millennia, an interest stimulated by the high speeds achieved by some fishes and their ability to hover and move smoothly in spite of numerous perturbations arising from the surrounding water as well as an intrinsic tendency by many species to roll belly up as discussed by the authors.
Abstract: Publisher Summary Studies of the relationships between fish form and swimming performance go back several millennia, an interest stimulated by the high speeds achieved by some fishes. More recently, the agility of fishes and other aquatic animals has caught the attention of both biologists and those who seek inspiration from nature for human-designed vehicles. Not only are fishes highly maneuverable, but they also hover and move smoothly in spite of numerous perturbations arising from the surrounding water as well as an intrinsic tendency by many species to roll belly-up. This high maneuverability and impressive stability result from the large number and diversity of control surfaces shared for both functions. No single motor system can efficiently power organisms over the wide range of speeds and acceleration rates typical of fishes, which necessitates performance range fractionation with motor-effector ‘‘gears'’ or gaits. Each gait works over a portion of the total performance range, and successive gaits are recruited as needed to provide for the increasing power requirement as speed increases. Because the performance power range for fishes is large, many gaits driven by many propulsors are necessary. The net weight of a fish in water is always small compared to that on land. Thus, the high density of water relaxes the pervading role of gravity experienced in air and the need to provide body support during movement. As a result, the body and all appendages of fishes can be used for movement, including maneuvers, and controlling posture and swimming trajectories.
93 citations
TL;DR: This chapter discusses the special characteristics of metabolism in the cold by considering their role in tissue and whole‐organism functional adjustments to cold, as well as the environmental forces that cause temperature‐dependent trade‐offs in biochemical and physiological tissue and cellular design.
Abstract: Publisher Summary Marine life in the polar, especially Antarctic, cold is characterized by a low to moderate pace at permanently low temperatures. This chapter discusses the special characteristics of metabolism in the cold by considering their role in tissue and whole‐organism functional adjustments to cold, as well as the environmental forces that cause temperature‐dependent trade‐offs in biochemical and physiological tissue and cellular design. The chapter highlights the knowledge of metabolic biochemistry of polar fishes, including molecular and cellular design and of individual tissue, functioning toward an understanding of the animal, its thermal specialization, and its integration into the ecosystem. The hypothesis of an oxygen‐limited thermal tolerance as a unifying principle in animals is important and is briefly discussed in the chapter.
86 citations
TL;DR: In this paper, the basic morphological structure of fish skulls, identify the principles of musculoskeletal biomechanics that transfer force and motion in fish feeding systems, and illustrate modifications of the basic pattern of prey capture that characterize some of the primary feeding modes in fishes.
Abstract: Publisher Summary This chapter presents the basic morphological structure of fish skulls, identify the principles of musculoskeletal biomechanics that transfer force and motion in fish feeding systems, and illustrate modifications of the basic pattern of prey capture that characterize some of the primary feeding modes in fishes. The evolutionary history of feeding biomechanics in fishes is a fascinating story of change in the structure and function of kinetic vertebrate skulls. From batoids to balistoids, there is a spectacular diversity of skull form and feeding mechanisms among fishes, from sit‐and‐wait predators that use high suction forces to engulf their prey, to species that chase their prey during an attack, and to fishes that remove pieces of their food using a biting strategy. The diversity of fishes and their feeding strategies, the importance of fish feeding to both freshwater and marine ecology, and the wide range of technological tools such as high‐speed video, electromyography, sonomicrometry, and fluid mechanics used in feeding studies have coalesced to make fish feeding one of the most fruitful areas of functional and evolutionary morphology. First, fish skulls are highly kinetic musculoskeletal systems with numerous movable elements. The dynamics of skull motion during rapid feeding events have thus been a prime focus of both theoretical and experimental research in biomechanics.
81 citations
TL;DR: In this paper, the effects of temperature on nitrogen metabolism was investigated in tropical fishes and it was shown that ammonia production increases with increasing temperature due to both increased metabolic rate and a switch to greater protein utilization.
Abstract: Publisher Summary Ammonia is mainly produced in fish through catabolism of amino acids. Ingested proteins are hydrolyzed producing amino acids, the catabolism of which leads to the release of ammonia. Ammonia production takes place mainly in the liver in fish but other tissues are also capable of doing so. Ammonia is produced by the transamination of amino acids followed by the deamination of glutamate and by the deamination of adenylates in fish muscle during severe exercise. Most aquatic animals keep body ammonia levels low by simply excreting excess ammonia produced through digestion and metabolism. The dietary protein requirement of fish increases at higher temperatures, possibly due to increased oxidation of amino acids reviewed the effects of temperature on nitrogen metabolism and concluded that as temperature increased an increasing percentage of aerobic metabolism was fueled by oxidation of protein. That is, ammonia production increases with increasing temperature due to both increased metabolic rate and a switch to greater protein utilization. However, this conclusion was based on studies of temperate fishes and, therefore, may not be applicable to tropical fishes. Tropical fishes show a marked increase in food intake and ammonia excretion with increasing temperature but the effect on protein metabolism is not known.
70 citations
TL;DR: The functional morphology of the pharyngeal jaw apparatus (PJA) in perciform fishes has been studied in this paper, which is used primarily in separating food from unwanted material and a variety of prey manipulation and processing behaviors.
Abstract: Publisher Summary This chapter presents the understanding of the functional morphology of the pharyngeal jaw apparatus (PJA) in perciform fishes. Much of the functional diversity seen in fish feeding systems lies in the mechanics of prey capture that involves the oral jaws and buccal cavity. However, an often-overlooked element of fish trophic diversity lies in the functioning of a second set of jaws, PJA, which is used primarily in separating food from unwanted material and a variety of forms of prey manipulation and processing behaviors. Fish trophic diversity is impacted by the PJA at two distinct levels. First, the presence of a second set of jaws in the feeding system promotes overall trophic diversity by increasing the range of musculo‐skeletal specializations for feeding. The PJA can be thought of as an additional independent axis of morphological diversity that fish lineages have explored during evolution. The structural independence of the oral and pharyngeal jaws permits potential autonomy in their evolution, and because the roles of prey capture and processing are potentially decoupled, the degree of specialization of each system is less constrained by the need to maintain secondary functions. Independent evolution of the oral and PJA has increased the range of fish feeding abilities and hence their feeding ecology. The second way in which the PJA influences overall fish trophic diversity comes about because this system is itself structurally complex.
64 citations
TL;DR: This work focuses on the study of the role of sex Steroids in the DiVerentiation of Alternative Reproductive Phenotypes and their role in the development of Sexually Bipotential Brain of Fish.
Abstract: 1. I ntroduction 2. A lternative Reproductive Strategies and Tactics 2.1. P atterns of Variation 2.2. T erminology of Alternative Reproductive Phenotypes 2.3. W hy Are Alternative Reproductive Phenotypes So Common in (Male) Fish? 3. S ex Determination, Sexual Differentiation, and Alternative Reproductive Phenotypes 4. S ex Steroids and Alternative Reproductive Phenotypes 4.1. P atterns of Sex Steroids in Species with Alternative Reproductive Tactics 4.2. O rganisational and Activational EVects of Sex Steroids in the DiVerentiation of Alternative Reproductive Phenotypes: The Relative Plasticity Hypothesis 4.3. A ndrogens and Alternative Reproductive Tactics: Cause or Consequence? 4.4. S teroid‐Binding Globulins, Steroidogenic Enzymes, and Steroid Receptors 5. N eural Mechanisms of Alternative Reproductive Behaviours 5.1. G nRH and the DiVerentiation of Alternative Reproductive Morphs 5.2. A VT and the DiVerentiation of Alternative Reproductive Behaviours 5.3. T he Sexually Bipotential Brain of Teleost Fish 6. I ntegrating Proximate and Ultimate Questions in the Study of Alternative Reproductive Tactics
TL;DR: This chapter reviews the functional capacities of fish skeletal structures and tissues, as those capacities have been determined by the measurement of mechanical properties under life‐like loading conditions.
Abstract: Publisher Summary This chapter reviews the functional capacities of fish skeletal structures and tissues, as those capacities have been determined by the measurement of mechanical properties under life‐like loading conditions. The mechanical workings of fishes have been approached in a two-pronged framework, with (1) muscle as the engine of motion and force and (2) water as the external source of resistance and purchase. The interaction of muscle and water certainly lays the foundation for behaviors as diverse as swimming, breathing, and feeding, but the interaction between them is only part of the picture. Understanding fishes as mechanical actors requires study of a third factor: the skeleton. This chapter defines skeleton broadly to include connective tissues such as tendon, ligament, cartilage, and bone that have a large component of extracellular collagen fibers. By measuring the mechanical properties of skeletal tissue and structures, one can begin modeling a few mechanical behaviors of a few species and understanding the integrated function of muscle, water, and skeleton. Even though the skeletal systems of fishes are complicated, analysis is helped by the often clear connection between skeletal structure and mechanical function, particularly when that correlation has convergently evolved. A clear causal connection is easily seen between the teeth and prey processing in heterodontid sharks and in sparid fish: their robust molariform teeth permit the crushing of hard prey such as mollusks and echinoderms.
TL;DR: These two adaptation processes are interdependent: metabolic adaptation and (long-term) genetic changes will alter different spectra—the spectrum of selection is altered by physiological changes, and the spectrum of physiological and metabolic patterns will be altered by genetic mutation over evolutionary time.
Abstract: Publisher Summary Adaptations of organisms to long‐ and short‐term environmental changes are one of the basic concepts of evolution. These adaptations involve genetic changes that will result in either metabolic/physiological adjustment to short‐term changes, or in changes at population and species levels. During the evolution, individuals must cope with short- and long‐term variations of the same physical parameters, i.e., temperature, pressure, and oxygen. In most cases, functional responses involve adjustments in metabolic processes that depend on the genetic make‐up and may result in anatomical and morphological variation. Evolutionary changes rely on genetic mutation and selection (in the broad sense), but a quantitative assessment of genetic variation alone fails to consider the phenotype range of variation of any given genotype. Thus, these two adaptation processes are interdependent: metabolic adaptation and (long-term) genetic changes will alter different spectra—the spectrum of selection is altered by physiological changes, and the spectrum of physiological and metabolic patterns will be altered by genetic mutation over evolutionary time. Currently, the interplay between metabolic and genetic adaptation may be the reflection of gene regulation processes: regulatory loci directly respond to specific environmental stimuli by triggering a specific series of ‘‘changes'’ and, in consequence, induce metabolic adjustments during the transcriptional phase..
TL;DR: In this paper, the structure of the musculotendinous system that provides the power for locomotion, and the relationship between muscle and body kinematics in steady swimming are discussed.
Abstract: Publisher Summary Axial undulation is a common mechanism for powering slow and continuous movements in fishes, and, because it derives power from a musculature that may comprise 50% or more of the body mass, this propulsive system can produce high thrust forces for fast swimming and high acceleration. Forward undulatory swimming depends on the coordinated action of lateral muscles to propagate a propulsive wave that travels with increasing amplitude from head to tail along the body. The three‐dimensional structure of the musculotendinous system provides the mechanical linkage that translates the muscle action into waves of body undulation, and is thus essential for a complete biomechanical analysis. This chapter discusses the structure of the musculotendinous system that provides the power for locomotion, and the relationship between muscle and body kinematics in steady swimming. Patterns of muscle activation and strain in different undulatory modes are summarized, as are recent studies on specializations related to high-performance swimming in tunas and lamnid sharks.
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TL;DR: In this paper, the authors considered the various mechanisms that a fish must use to achieve a fast start swimming maneuver and considered the mechanics of fast start in a sequential sequence of events from the neural activation of the muscles, the generation of muscle force that acts to bend the body, the development of the typical kinematic patterns of the fast start, and finally the hydrodynamic forces that act to accelerate the body.
Abstract: Publisher Summary Fast starts are high acceleration swimming maneuvers, either starting from rest or imposed upon a period of steady swimming. Fast starts are important for most fishes when escaping predators and for some fishes in achieving prey capture, and thus they are vital components of a fish's locomotory repertoire. Fast‐start performances can be measured in terms of acceleration, velocity achieved, or distance traveled during the initial moments of the start. This chapter considers the various mechanisms that a fish must use to achieve a fast‐start swimming maneuver. The mechanics of the fast start are driven by a number of different processes, including force generation by muscles, transmission of those forces to appropriate parts of body, and the transfer of those forces to the water. Studies of fast‐start swimming have typically focused on specific aspects of the fast‐start maneuver, and so the information presented here is synthesized from a range of different experimental and theoretical observations. Fast starts are typically classified by the shape to which the body bends. The mechanics of the fast start are considered in a sequential sequence of events from the neural activation of the muscles, the generation of muscle force that acts to bend the body, the development of the typical kinematic patterns of the fast start, and finally the generation of the hydrodynamic forces that act to accelerate the body are described.
TL;DR: The results suggest that to maintain internal Na+ and Cl- levels higher than the surrounding fresh waters, fish must balance diffusive losses with active uptake and that the gills are the main site for both of these processes, although the gut and kidney play roles too.
Abstract: Publisher Summary The understanding about the mechanisms of ion regulation in freshwater fishes comes from a wealth of studies on a relatively small number of model species from temperate climates, primarily from the Family Salmonidae and to a lesser extent Cyprinidae The results suggest that to maintain internal Na+ and Cl- levels higher than the surrounding fresh waters, fish must balance diffusive losses with active uptake and that the gills are the main site for both of these processes, although the gut and kidney play roles too Recent studies on the cyprinodont killifish in freshwater indicate that the ionic transport systems are fundamentally different from those of the model species Extremely ion-poor, acidic waters, such as those found in the Rio Negro, pose a variety of challenges for ion regulation in freshwater fish The fish of the Rio Negro pose a superb opportunity to explore the range of physiological adaptations for ion regulation in ion-poor, acidic waters as well as the evolution of these specializations within a phylogenetic framework To illustrate this potential, the chapter describes the current understanding regarding mechanisms of ion regulation in freshwater fishes and what is known about the effects of ion-poor, acidic waters on ion regulation
TL;DR: In many species, but not all, there is notable axial variation in the speed of red muscle within an individual, with the more anterior muscles tending to be faster than the posterior as discussed by the authors.
Abstract: Publisher Summary The majority of studies on the anatomy and contractile characteristics of fish skeletal muscle have focused on species that employ some degree of axial body undulation to power locomotion, typically anguilliform, carangiform, subcarangiform, and thunniform. Fish size, the location of the muscle in the fish, and temperature have pronounced effects on many aspects of muscle contraction. In many species, but not all, there is notable axial variation in the speed of red muscle within an individual, with the more‐anterior muscles tending to be faster than the posterior. It is suggested that this may serve to compensate for the smaller strains experienced in the anterior myotomes of many fishes during swimming, allowing the muscles there to produce relatively more power than if they had the slower kinetics of more‐posterior muscles. There is also often notable axial variation in power output of red muscle in swimming fishes, but this is associated more with the manner in which the muscle is used than with its inherent abilities. Radial variation in muscle speed has also been noted in tuna, in which the deeper red fibers are faster and perhaps better equipped to work when warm. This variability in the contractile characteristics of a given fiber type within an individual appears unique to the fish, and may have a basis in compensating for axial variation in strain and bending kinematics, or in promoting axial variation in muscle function during swimming.
TL;DR: This chapter focuses on the known aspects of the circulatory physiology of polar fishes, which span from the effects of temperature on physical characteristics to interactions between different cells up to the integrated response of the entire animal.
Abstract: Publisher Summary This chapter focuses on the known aspects of the circulatory physiology of polar fishes. Temperature affects the physiology of poikilotherm organisms, such as fish, by affecting the rate of chemical reactions. These effects are reflected in many physiological processes, including the cardiovascular system at both the metabolic and the morphological level. Data are limited on the cardiovascular effects of temperature for fish living in polar environments, as is the case for many temperate fish species. Nevertheless, it still seems as if the cardiovascular biology of different species to some extent mirrors the thermal tolerance limits for each group. The aspects of cardio circulatory enantiostasis span from the effects of temperature on physical characteristics to interactions between different cells up to the integrated response of the entire animal.
TL;DR: Seasonality, feeding migrations, and ontogeny result in dietary modulations that are reflected in the intestinal nutrient transport=uptake as well, and the mechanistic basis for changes in nutrient absorption can be analyzed using brush border membrane vesicles, intact intestinal tissue preparations (in vitro), and the “whole animal” approach.
Abstract: Publisher Summary The feeding process is composed of nine stereotyped movement patterns (particulate intake, gulping, rinsing, spitting, selective retention of food, transport, crushing, grinding, and deglutition). The sequence and frequency of these movements are adjusted to the type, size, and texture of food. Better understandings of food intake and mechanisms of food processing reveal intraspecies plasticity and interspecies trophic interactions. This knowledge is essential to manage multispecies communities and maximize productivity of polyculture systems. Feeding periodicity has been observed in marine fishes feeding on algae at the time of peak algal energy due to early afternoon photosynthesis. Morphological features of the digestive system are of great consequence in respect to the type of diet larval/juvenile fish are able to utilize, especially at the highest growth rates during early ontogenetic development. Intestinal transepithelial transport of nutrients reflects a general tendency for fish species to consume diets containing either more carbohydrates (herbivores and omnivores) or more protein/amino acids (carnivores). Seasonality, feeding migrations, and ontogeny result in dietary modulations that are reflected in the intestinal nutrient transport=uptake as well. The mechanistic basis for changes in nutrient absorption can be analyzed using brush border membrane vesicles (BBMV), intact intestinal tissue preparations (in vitro), and the “whole animal” approach where nutrients acquired are measured along the digestive tract.
TL;DR: A review of morphology, kinematics, and force production of paired pectoral fin undergoing oscillatory locomotor motions can be found in this paper, where the authors present an overview of current research into undulatory pectral fin swimming mechanisms.
Abstract: Publisher Summary Fishes use a diverse array of kinematic mechanisms to swim. This diversity arises from different combinations of body and fin use and from different ways of deforming the body and fins during propulsion. These swimming mechanisms (or locomotor modes) have been named according to the family of fishes that commonly expresses the mode. To date, nearly 20 distinct locomotor modes have been identified for steadily swimming fishes. This chapter describes how deforming bodies and fins interact with the surrounding fluid to generate propulsive forces, how variation in body and fin movements and variation in body and fin shape affect the generation of different force components (including lift, thrust, and side forces), which locomotor movements and propulsor shapes generate swimming forces with minimal wasted energy, and which measures of swimming performance (e.g., maximum force versus maximum efficiency) are most important in influencing how fishes exploit resources in their environment. The chapter reviews recent progress in the study of morphology, kinematics, and force production of the pectoral fins of fishes. It focuses on the mechanics of paired pectoral fins undergoing oscillatory locomotor motions, and presents an overview of current research into undulatory pectoral fin swimming mechanisms.
TL;DR: This chapter describes that metabolic rate is influenced by a wide range of factors (temperature, body mass, activity level, feeding state, etc); therefore, there has been quite a lot of discussion on the best way to determine the standard metabolic rate correctly.
Abstract: Publisher Summary This chapter focuses on the respiratory systems and metabolic rates in fishes. Fish living in the cold waters found at the poles are exposed to extreme temperatures that have important biochemical and physiological consequences. Because of the effects of temperature on the rate of biochemical reactions, fish exposed to cold water have reduced the metabolic rates. It is well known that the metabolic rate of fish decreases with temperature. Based on early experiments on goldfish acutely exposed to cold, the concept of metabolic cold adaptation (MCA) was born. This chapter also describes that metabolic rate is influenced by a wide range of factors (temperature, body mass, activity level, feeding state, etc.); therefore, there has been quite a lot of discussion on the best way to determine the standard metabolic rate correctly.
TL;DR: This chapter focuses on the important fact that Arctic and Antarctic Oceans differ in their physiogeographic characteristics, despite that both share many features beyond being just frigid.
Abstract: Publisher Summary This chapter discusses a succinct comparison of the physiogeographic characteristics of the Arctic and Antarctic marine systems to illustrate the similarities and difference. This chapter focuses on the important fact that Arctic and Antarctic Oceans differ in their physiogeographic characteristics, despite that both share many features beyond being just frigid. The Arctic marine region is composed of a “land‐locked” ice‐covered Arctic Ocean, mostly surrounded by continental landmasses, whereas the Antarctic marine region is an ice‐covered continent surrounded by an unrestricted Southern Ocean. In comparison to the Antarctic marine system, the Arctic is only about one‐third the size of the Southern Ocean marine system and the continental shelves are shallow.
TL;DR: The equations that are commonly used to explain the growth of tropical fishes are described and the range of growth rates and maximum sizes that are achieved are presented and it is far from clear if tropical fishes will actually grow faster or more consistently than colder water species.
Abstract: Publisher Summary This chapter describes the equations that are commonly used to explain the growth of tropical fishes and presents the range of growth rates and maximum sizes that are achieved. By focusing on tropical fishes, it raises the question as to whether the growth of tropical fishes displays any particular features not shown by fishes from other regions. It might be assumed that they can grow faster and without seasonal variation in growth rate because of the lack of large annual variations in temperature. However, many other factors can also limit growth, including local productivity and oxygen availability, so it is far from clear if tropical fishes will actually grow faster or more consistently than colder water species. To determine the rate of growth it is essential to know the age of the fish. In temperate waters hard structures such as scales, otoliths, spines, and bones often put down a clear annual winter growth check so that it is possible to determine the number of winters the fish has experienced. Tropical fishes have been observed to produce a single annual growth check. There are clear indications that the growth rates achieved by fish vary with the density of their populations, which may vary naturally, or by human exploitation.
TL;DR: The biomechanical challenges for aerial respiratory pumps stem from predation risk, hydrostatic pressure, buoyancy, surface tension, and mechanical conflicts between breathing and feeding as mentioned in this paper, which is a common problem for aquatic respiratory pumps.
Abstract: Publisher Summary To facilitate oxygen uptake and carbon dioxide excretion, fishes ventilate their gas exchange surfaces with water or air. Because water and air differ substantially in their density, viscosity, and oxygen content, the biomechanical problems associated with aquatic and aerial ventilation also differ. Nonetheless, aerial and aquatic respiratory pumps do share one biomechanical challenge stemming from the fact that muscles only generate force in the direction of shortening. It is a simple matter for muscle contraction to generate positive pressure and force fluid out of a cavity, but respiratory pumps also require an expansive phase to refill the cavity with new fluid. Some biomechanical trickery is necessary for muscle shortening to cause the expansion of a cavity and the generation of subambient pressure. This trickery generally takes the form of a lever system or occasionally elastic recoil. The primary biomechanical problems in the design of aquatic respiratory pumps stem from the physical and chemical properties of water: high density, high viscosity, and low oxygen content. The biomechanical challenges for aerial respiratory pumps stem from predation risk, hydrostatic pressure, buoyancy, surface tension, and mechanical conflicts between breathing and feeding.
TL;DR: In this paper, the current state of the field of fish biomechanics in a management context, identifying advances and gaps in knowledge that may both aid the development of sound management policies and provide helpful directions for future research.
Abstract: Publisher Summary The field of biomechanics tends focuses on suborganismal processes. Muscle kinetics, body and fin morphologies, and sensory systems characterize the mechanical interactions between fishes and their habitat. These in turn define the fishes' ability to exploit their environment, influencing not only home range, but also reproductive success, energetics, trophic interactions, and the scope of available habitats. Fisheries managers must take into account more than ecology and life history theory when developing policy: physiology, energetics, behavior, and stochastic habitat and ecosystem‐level processes must all be considered. The chapter discusses the current state of the field of fish biomechanics in a management context, identifying advances and gaps in knowledge that may both aid the development of sound management policies and provide helpful directions for future research. When developing conservation policy, managers often focus on critical life history stages: those parts of the life cycle that determine population-level processes. Many factors influence whether and in what condition fishes progress through these life stages. The chapter also presents a summary of gaps in current knowledge, with suggestions to how future biomechanics research might help to improve practices in both fisheries management and conservation.
TL;DR: This chapter focuses on recent advances in the understanding of the control of cardiorespiratory processes in these fish with a brief review of structure and function designed to place discussion of control mechanisms in perspective.
Abstract: Publisher Summary The high temperatures of the tropical aquatic environment, often accompanied by hypoxia and hypercarbia/acidosis, have also given rise to a tremendous adaptive radiation in cardiorespiratory strategies designed to enhance survival under these conditions. This chapter presents the structure, function, and control of the respiratory and circulatory systems in these fishes. The chapter focuses on recent advances in the understanding of the control of cardiorespiratory processes in these fish with a brief review of structure and function designed to place discussion of control mechanisms in perspective. The great majority of tropical fishes continue to breathe water like their temperate relatives. Many species of tropical fish have evolved no special mechanisms for dealing with harsh conditions such as hypoxia/anoxia but constantly sense and monitor environmental conditions and migrate to better areas. These migrations are usually short, moving between stagnant areas and areas with higher water flow. The mechanisms involved include regulation of different hemoglobin fractions, adjustment of intra-erythrocytic levels of organophosphates, changes in hematocrit/hemoglobin and metabolic suppression; almost all under catecholaminergic control. The primary adaptations seen in the respiratory organs of water-breathers living in oxygen-poor waters are associated with gill diffusing capacity. Here we see both interspecies and intraspecies adaptations.
TL;DR: This chapter describes polar fishes from a biogeographical point of view, employing areas with major shifts in species composition as borders for the Arctic and Antarctic areas, often defined by oceanic frontal systems and topographical structures, such as submerged ridges.
Abstract: Publisher Summary This chapter describes polar fishes from a biogeographical point of view, employing areas with major shifts in species composition as borders for the Arctic and Antarctic areas. These are often defined by oceanic frontal systems and topographical structures, such as submerged ridges. The two polar areas of the world contain 538 species of fish, 289 in the Arctic and 252 in Antarctica. The Arctic fish fauna displays a number of interesting adaptations to the harsh environment that is also reflected in the distribution patterns. The Arctic fish fauna is dominated by phylogenetically young families, with few representatives of old families, particularly in deep waters. In the Antarctic, ice cover plays a more important role in fish distributions than salinity. Deepwater sampling is inadequate in Antarctica and most deep‐sea species are known from very few specimens.