Fish migration is important and spectacular. Migratory fish gather energy in one portion of the environment and transport it to other areas, where it often becomes available to humans or to other elements in the ecosystem. Migration brings fish into situations that allow easy harvest as they concentrate along migration routes. Their journeys also make them vulnerable to human intereference at critical points along their route. Salmon, for example, may harvest plankton in the open ocean and transport that food energy to coastal and inland regions, where it is captured by fisheries or deposited in inland streams and utilized by the flora and fauna of the region. These salmon are able to complete journeys of thousands of kilometers from their natal streams to oceanic feeding grounds and back to the same home streams, an accomplishment that strains our credi bili ty . We now understand some of the timing and guiding stimuli used in these migrations, and mechanisms can be logically proposed, on the basis of the established abilities of fishes, to account for the unexplained portions of the migrations. There is no single factor guiding these fish. Instead, they are dependent on the presence in their environment of a great variety of appropriate orienting and timing stimuli. These stimuli are vulnerable to human interference. The more widespread and easily available the information on these requirements, the more readily fish can be protected from such interference.

Fisheries and Aquaculture theme is a component of Encyclopedia of Food and Agricultural Sciences, Engineering and Technology Resources in the global Encyclopedia of Life Support Systems (EOLSS), which is an integrated compendium of twenty one Encyclopedias. Fisheries are a major life support system and the main purpose of this theme on Fisheries and Aquaculture is to provide baseline information and latest knowledge at the dawn of this century to facilitate vital fisheries recovery before their irreparable collapse. This Theme on Fisheries and Aquaculture is divided into five topics. It starts with discussions on major issues and challenges in “Harvesting the Seas”, with emphasis on the role and importance of the fisheries sector and its environment, and introduces trends and perspectives in marine fisheries, including allocation of use rights, subsidies, and port management. The next two topics present an in-depth and detailed knowledge on fish and other aquatic living resources that are commercially exploited and/or farmed. The third topic on Inland Fisheries presents salmonid fish, eels, shad, whitefish and smelt, carp, perch, pike and bass, tilapia, frog, and crustaceans. The fourth topic presents a comprehensive review of trends and perspectives in Aquaculture: Principles and Prospects. The fifth topic on Economics of Fisheries and Aquaculture reviews the latest views and concepts useful to apprehend the fisheries management regime, including a comparative static economic theory and a dynamic theory of fishery, spatial bioeconomic dynamics and role of international law in the management of marine fisheries, rights-based and community fisheries management, aquaculture economics, and game theory and fisheries. These five volumes are aimed at the following five major target audiences: University and College Students Educators, Professional Practitioners, Research Personnel and Policy Analysts, Managers, and Decision Makers, NGOs and GOs.

What defines a small stream? For Dave Hughes, it's not size but "that sense of intimacy" you get when you can observe the whole stream and "feel that you're a large and integral part of it." Hughes draws on his years of experience to teach you everything you need to know about fishing small streams, from choosing rods and flies to reading the weather and water. Hughes knows that successful fly fishing is more than just catching the most or the biggest fish. Small streams provide the opportunity for exploration and discovery—in addition to the fish. This second edition contains new chapters on reading the seasons and tenkara and is superbly illustrated with more than 100 new color photos.