ISSN:0002-8487    

DOI:10.1577/1548-8659-119.4.567

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/1548-8659-119.4.571

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The Ontario Fisheries Research Laboratory was founded in 1920 at the University of Toronto. Fisheries research by the laboratory became more strategic when F. E. J. Fry emerged as a leader in the 1940s. His field work, conducted iteratively with complementary laboratory work, invited questions about the fundamental niche, variation in year-class strength, and biogeography. His emphasis was on physiological ecology at the organism and population levels. His excellent working relationships with government administrators, fishermen, and other researchers led to the expansion of strategic fishery science. He initiated, for example, five data series that were continued by institutions after the series had served Fry's original needs. Thus questions about whitefish exploitation were succeeded by those about eutrophication, climatic change supplanted thermal effluents as a focus, and studies of muskellunge growth led to evaluations of stocking success and models of population dynamics. As an accomplished “prospector,” Fry apparently knew that clear data would not only help to resolve current problems, they would also provoke unforeseeable scientific questions.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1990)119<0574:FEJFFS>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Metabolic models of thermal acclimation of fishes are generally based on routine rates of oxygen consumption and, therefore, are confounded by metabolic changes due to variation in random activity. My objectives were to describe the amount, direction, and time course of change in the standard metabolic rate of rainbow troutOncorhynchus mykisswhile the fish acclimated to warm and cold temperature, and to account for the energy costs of random swimming. Rainbow trout (100–250 g) were acclimated to 10 and 20°C and tested at 10, 15, and 20°C. Random activity and oxygen consumption were monitored at acclimation temperatures immediately after acute temperature exposures and, in some cases, for several days after temperature changes. Random swimming activity and standard metabolic rate were strongly influenced by both recent thermal history and acute temperature exposure. The initial activity response depended on the extent of the temperature change, and included an orthokinetic reaction when the new temperature deviated widely from the final thermal preferendum. During acclimation, standard metabolic rate was adjusted independently of the direct kinetic effect of temperature in a manner corresponding to partial metabolic compensation. The result was a 53% reduction in standard metabolic rate during warm acclimation (10 to 20°C) and a 35% increase during cold acclimation (20 to 10°C. The time course of warm and cold metabolic acclimation over the 10–20°C range was about 96 h. Analysis of data for rainbow trout and other salmonids indicated that warm and cold metabolic acclimation resulted in increased scope for activity, the latter being equivalent to the maximum sustained usable power – i.e., power that is available for ancillary and discretionary activities. Conservation and budgeting of power output to maximize the availability of usable power appears to be the essence of capacity adaption, not simply stabilization of metabolic function as has often been suggested.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1990)119<0585:MTCBRT>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

We present a model that accounts for the variety in observed relationships between temperature preference and acclimation in fishes. The preferred temperature is that temperature at which Fry's scope for metabolism is maximized. Thermal acclimation shifts the temperature for maximum scope in such a way that Zahn's types of temperature-preference acclimation correspond with Precht's types of metabolic compensation. The model predicts that fishes exhibiting Precht's “partial,” “no,” and “inverse” compensation prefer temperatures that are increasing, independent, and decreasing functions of acclimation temperature, respectively. Experiments with bluegillLepomis macrochirusand blue tilapiaTilapia aurea, together with information from the literature, provide support for the model.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1990)119<0601:TPVAIF>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The maximum power principle suggests that successful biological systems maximize the flow of useful energy. Using this principle in conjunction with Fry's metabolic scope concept, we have developed a model of behavioral thermoregulation for fishes that reasonably predicts frequency distributions and swimming speeds of fish in thermal gradients: fish respond to temperature gradients by swimming at speeds that are proportional to the rate of change of metabolic scope with respect to temperature. As a result, reduced thermoregulatory swimming power occurs at temperatures that give higher levels of metabolic scope; this maximizes both available surplus power and residence time under conditions of high surplus power availability. Within the zone of high residence time (=preferred temperature zone), fish respond to changes in the gradient of metabolic scope with increased turning, thus increasing their frequency of occurrence near the temperature that permits maximum metabolic scope.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1990)119<0611:TMPPIB>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The concept of scope for activity, defined as the difference between maximum metabolic rate and the animal's resting or standard metabolic rate, is well established in the fields of comparative and exercise biochemistry and physiology. It has been particularly useful in unravelling adaptational options for organisms facing environmental changes or stresses. Here I examine the concept of scope for survival, which is a conceptual “mirror” image of the scope for activity and is defined as the difference between resting or standard metabolic rate and the lowest sustainable rate to which metabolism may be suppressed. Metabolic arrest occurs frequently in the animal kingdom in the face of extreme deficiencies in oxygen, heat, or water. Although many mechanisms that allow metabolism to be suppressed well below routine or standard rates have yet to be unravelled, it is clear that the overall process universally seems to involve a controlled decrease in metabolic and organelle functions coupled with a simultaneous controlled stabilization of macromolecular and organelle structures.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1990)119<0622:SFSACT>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

As aquatic vertebrates increase in size, hydrofoils, which use lift to generate thrust, are increasingly used as propulsors. One factor affecting the magnitude of the lift force is the area of the propulsor. Resistance to cruising and sprints is mainly due to drag, but inertia is important during maneuvers when animals accelerate or turn. The inertia of the body and entrained water, which is proportional to body volume, resists acceleration. Because a thrust that is proportional to surface area is used to maneuver a resistance that is proportional to volume, acceleration performance and maneuverability are expected to decline with increasing size, This trend is ameliorated to some extent by the high swimming speeds attainable by warm-bodied vertebrates and the reduced resistance to acceleration characteristic of the skeletons of dolphins and ichthyosaurs. Maneuvers are essential for capture of elusive prey and avoidance of predators. As they increase in size, aquatic vertebrates use various means to ensure that their prey are less maneuverable than they. These include consumption of increasingly smaller prey relative to predator body size (culminating in filter feeding by the largest aquatic vertebrates); behaviors to concentrate, disturb, and disorient prey; and ambushing or suction feeding that avoid whole-body acceleration. Advantages of warm muscles are seen in the ability of endotherms to take more maneuverable prey than can ectotherms of the same size. Young stages of large aquatic vertebrates could be especially vulnerable to predators; viviparity or spawning in productive patches provides for rapid growth through vulnerable stages.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1990)119<0629:LITBOL>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Subsequent to development of the lampricide program, sea lampreysPetromyzon marinusin Lake Michigan have demonstrated increased growth rates in parallel with expanded stocking rates of salmon and trout. Based on bioenergetics modeling of maximum and minimum growth and feeding rates, I estimated sea lamprey effects as the “scope for mortality,” which depends on host size and sea lamprey size, For small host fishes, sea lamprey-induced mortality may have increased approximately sixfold over the past two decades.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1990)119<0642:TSFMCB>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Bioenergetic models of growth endeavor to integrate food-processing transactions with energy expenditures imposed by abiotic and biotic factors. Some components of these models have lagged behind others in the synthesis of new information. A case in point is heat increment, a measure of metabolic work primarily for the postabsorptive processes that follow the ingestion of food. Importantly, the energy requirements for grasping, chewing, and swallowing food are technically distinct from those for heat increment but are experimentally difficult to separate from them. In order to take special account of these mechanical aspects, we suggest modifying the term “heat increment” (also known as specific dynamic action) to the less-precise “apparent heat increment.” Bioenergetic models invariably incorporate the assumption that apparent heat increment, relative to food intake, is independent of other variables. Laboratory studies have revealed that apparent heat increment is not always a fixed proportion of gross energy intake. Values reported range from 3 to 41% for fish fed natural diets and from 11 to 29% for those given formulated diets. Generally, apparent heat increment increases with meal size and body weight, but declines with body weight when food intake is fixed. Apparent heat increment increases with temperature, It is related to the proportion of dietary protein either directly or in an asymptotic manner. In some cases, increases in dietary lipid reduce apparent heat increment by reducing protein catabolism. In most modeling situations, consequently, the practice of adopting a fixed value for apparent heat increment relative to ingested or digestible energy leads to spurious outputs. We recommend that creators of future bioenergetic models consider the findings reviewed in this article.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1990)119<0649:HIASOD>2.3.CO;2

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor