Environmental Biology of Fishes 

About: Environmental Biology of Fishes is an academic journal published by Springer Science+Business Media. The journal publishes majorly in the area(s): Population & Threatened species. It has an ISSN identifier of 0378-1909. Over the lifetime, 5277 publications have been published receiving 161772 citations.

Natural and sexual selection on color patterns in poeciliid fishes

Abstract: In poeciliid fishes, sexual dichromism is associated with larger size and larger broods, but there is no relationship between sexual size dimorphism and sexual dichromism, or between degree of dichromism and color pattern polymorphism. Factors are discussed which influence the evolution of color pattern polymorphisms, sexual dimorphism and dichromism. Detailed studies of South American species have shown that the color patterns of poeciliid fishes have predictable effects in (1) avoiding diurnal visually hunting predators; (2) mating success; and (3) species recognition. Data from some Central American species indicate that some color pattern elements may be closely linked to physiologically variable loci, which further affect the variation in color patterns. Different elements of any given color pattern can be influenced by different modes of natural selection; in guppies the relationship between predation intensity and color pattern is different for melanin, carotenoid, and structural colors. Different color patterns have different degrees of conspicuousness on different backgrounds, and may appear differently to predators and mates with differing visual abilities.

Temperature Tolerances of North American Freshwater Fishes Exposed to Dynamic Changes in Temperature

Abstract: Traditionally lower and upper temperature tolerances of fishes have been quantified in the laboratory via three different experimental approaches: the Fry or incipient lethal temperature (ILT), critical thermal (CTM) and chronic lethal (CLM) methodologies. Although these three experimental laboratory approaches generate endpoints which are quantitatively expressed as a temperature, are determined experimentally with random samples of fish acclimated to specific temperatures, and involve both time and temperature as major test variables, they do not quantify the same response. All three approaches generate valuable, albeit different, information concerning the temperature tolerance of a species. In this review we have summarized published research concerning the tolerance of North American freshwater fishes to dynamic changes in temperature, i.e., tolerance is tested by methods that gradually change temperatures until biological stress is observed. We found more than 450 individual temperature tolerances listed in 80 publications which present original dynamic temperature tolerance data for 116 species, 7 subspecies and 7 hybrids from 19 families of North American freshwater fishes. This total represents about 1/3 of the families and 1/6 of the known North American freshwater species. Temperature tolerance data were partitioned by experimental approach, i.e., critical thermal method (CTM) and chronic lethal method (CLM), and direction of temperature change. Although both CTM and CLM expose fish to dynamic changes in water temperature, these two methods differ in temperature change rates and test endpoints, and hence measure different aspects of thermal stress. A majority of the 80 studies employed CTM to assess temperature tolerance, in particular determination of CTmaxima. One or more CTmaxima has been reported for 108 fishes. Twenty-two fishes have reported highest CTmaxima of 40°C or higher. Several species in the family Cyprinodontidae have generated some of the highest CTmaxima reported for any ectothermic vertebrate. For a variety of reasons, data concerning tolerance of low temperatures are less plentiful. Low temperature tolerance quantified as either CTminima or CLminima were found for a total of 37 fishes. Acclimation temperature exerts a major effect on the temperature tolerance of most North American fish species and it is usually strongly linearly related to both CTmaxima and CTminima. Although we uncovered dynamic temperature tolerance data for 130 fishes, only a single dynamic, temperature tolerance polygon has been published, that for the sheepshead minnow, Cyprinodon variegatus.

Reproductive strategies of coastal marine fishes in the tropics

Abstract: A synthesis of ethnobiological, behavioral and physical oceanographic information leads to the conclusion that temperate zone models of reproductive strategy are inapplicable to many fishes of the coastal tropics. Intense predation appears to exert heavy selection pressure on fishes that spend their adult lives in coral, mangrove or tropical seagrass communities. Many exhibit spawning behaviors and spawn at times and locations that favor the transport of their pelagic eggs and pelagic larvae offshore where predation is reduced. This creates a countervailing selection pressure — the need to return the larvae to shallow water once they are ready to colonize their post-larval habitats. Accordingly, spawning is often concentrated at times of the year when prevailing winds or currents are at their weakest, thereby reducing the transport of larvae long distances from where they originated. Spawning is also concentrated in the vicinity of nearshore gyres which similarly favor the ultimate return of the larvae to their natal area. Among these species, therefore, offshore larval dispersal does not seem to be an adaptation for dispersal of the species, but rather an evolutionary response to intense predation pressure in the adult habitats. Lunar reproductive periodicity is more common among these species than has previously been recognized, and is one of the strategies employed to enhance the offshore flushing of eggs and larvae.

Implications of fish home range size and relocation for marine reserve function

Abstract: Reserves are being used increasingly to conserve fish communities and populations under threat from overfishing, but little consideration has been given to how fish behavior might affect reserve function. This review examines the implications of how fish use space, in particular the occurrence and size of home ranges and the frequency and direction of home range relocations. Examples are drawn primarily from the literature on coral reef fishes, but the principles apply to other habitats. Reserves can protect fish species only if individuals restrict their movements to a localized home range during at least part of the life cycle. Home range sizes increase with body size. In small reserves, a significant proportion of fish whose home ranges are centered within the reserve can be exposed to fishing mortality because their home ranges include non-reserve areas. Relocation of home ranges following initial settlement increases exposure to the fishery, especially if habitat selection is frequency-dependent. Distance, barriers, and costs of movement counter such redistribution. These considerations lead to predictions that population density and mean fish size (1) will form gradients across reserve boundaries with maxima in the center of the reserve and minima outside the reserve away from the boundary; (2) will increase rapidly in newly established reserves, only later providing ‘spillover’ to adjacent fisheries as density-dependent emigration begins to take effect; and (3) will be higher in reserves that are larger and have higher area:edge ratios, more habitat types, natural barriers between reserve and non-reserve areas, and higher habitat quality inside than outside the reserve. (4) Species with low mobility and weak density-dependence of space use will show the greatest increase in reserves and the strongest benefit for population reproductive capacity, but those with intermediate levels of these traits will provide the greatest spillover benefit to nearby fisheries.

Dissolved oxygen and fish behavior

Abstract: This essay reviews the behavioral responses of fish to reduced levels of dissolved oxygen from the perspective of optimization theory as used in contemporary behavioral ecology. A consideration of oxygen as a resource suggests that net oxygen gain per unit of energy expenditure will be the most useful currency for ecological models of breathing. In the process of oxygen uptake, fish always expend energy on perfusion, usually on ventilation and often on locomotion. These costs, and the risk of predation, will vary with oxygen availability and the type of behavioral response shown. The principal categories of behavioral response to reduced external availability of dissolved oxygen are (1) changes in activity, (2) increased use of air breathing, (3) increased use of aquatic surface respiration, and (4) vertical or horizontal habitat changes. Fish should choose whichever combination of responses minimizes the costs of meeting their oxygen demands. A small number of studies provides qualitative support for this prediction.