The study of ecological processes that affect exploited aquatic organisms, in both marine and fresh-water environments. Because this field is primarily motivated by an attempt to harvest populations, special attention has been given to understanding the regulation of aquatic populations by nature and humans. The foundations of fisheries ecology lie in population and community ecology, with ideas and methods from physiology, genetics, molecular biology, and epidemiology being increasingly relevant. Because of issues associated with harvesting biological resources, fisheries ecology must also go beyond biology and ecology into sociology and economics. Ecology The problem of regulating the exploitation of aquatic organisms in order to ensure sustained harvest lies at the core of fisheries ecology. Most experts agree that the harvest of marine resources has peaked and increased yields are likely to come only from fine-tuning of regulations on stocks that are fully exploited. The typical unit at which management efforts are directed is the exploited population, customarily termed a stock. A central aspect of assessing fisheries resources is to identify these stocks and determine how isolated they are from other stocks of the same species. For example, there are 20 major recognized stocks of cod in the North Atlantic Ocean, each on the whole isolated from every other and distinct with regard to several biological characteristics that determine the potential for harvest. The three main population processes that govern the size and productivity of given stock are somatic growth, mortality, and recruitment (the incorporation of new individuals into the population through birth). A typical assessment of an exploited stock includes the study of these three processes, as well as some protocol to estimate abundance. From this information, and aided by mathematical models and statistical tools, fisheries biologists produce recommendations on how many individuals to harvest, of what size or age, when, and where. The early history of modern fishing was characterized by attempts to ensure an increasing supply of aquatic organisms at all costs. In the last two decades, that view has yielded to a more realistic perspective, increasingly heedful to the natural limits of aquatic resources and to many environmental aspects of harvested systems. These include habitat degradation, overfishing, incidental mortality of nontarget species, and the indirect effects of species removal at the ecosystem level. Marine conservation Marine fisheries |
