Population dynamics of fisheriesA fishery is an area with an associated fish or aquatic population which is harvested for its commercial or recreational value. Fisheries can be wild or farmed. Population dynamics describes the ways in which a given population grows and shrinks over time, as controlled by birth, death, and migration. It is the basis for understanding changing fishery patterns and issues such as habitat destruction, predation and optimal harvesting rates. The population dynamics of fisheries is used by fisheries scientists to determine sustainable yields.
Fishing down the food webFishing down the food web is the process whereby fisheries in a given ecosystem, "having depleted the large predatory fish on top of the food web, turn to increasingly smaller species, finally ending up with previously spurned small fish and invertebrates". The process was first demonstrated by the fisheries scientist Daniel Pauly and others in an article published in the journal Science in 1998. Large predator fish with higher trophic levels have been depleted in wild fisheries.
PiscivoreUn animal piscivore (du latin : , « poisson » et « avaler, manger ») ou ichtyophage (du [grec ancien], « mangeur de poissons », composé de (« poisson ») et de ) est un animal se nourrissant de poissons. On connait un large éventail d'espèces occasionnellement ou uniquement ichtyophages ; elles jouent un rôle important de régulation et un rôle eco-épidémiologiquement important d’« assainissement » (sélection naturelle, élimination des animaux malades...).
MaricultureLa mariculture concerne, en aquaculture, l'élevage d'animaux marins (fermes ou ranchs marins) ou la culture d'algues (fermes d'algues) directement dans le milieu naturel marin ou bien à partir d'eau de mer brute prélevée à proximité du site d'exploitation (mariculture en bassin). Algoculture Conchyliculture Mytiliculture Ostréiculture Pisciculture Katavic, Ivan. (1999). Mariculture in the New Millennium. ACS, 223-229. McKindsey, C. W. (2005). La mariculture: peut-elle augmenter la productivité des écosystèmes.
Cascade effect (ecology)An ecological cascade effect is a series of secondary extinctions that are triggered by the primary extinction of a key species in an ecosystem. Secondary extinctions are likely to occur when the threatened species are: dependent on a few specific food sources, mutualistic (dependent on the key species in some way), or forced to coexist with an invasive species that is introduced to the ecosystem. Species introductions to a foreign ecosystem can often devastate entire communities, and even entire ecosystems.
Mesopredator release hypothesisThe mesopredator release hypothesis is an ecological theory used to describe the interrelated population dynamics between apex predators and mesopredators within an ecosystem, such that a collapsing population of the former results in dramatically increased populations of the latter. This hypothesis describes the phenomenon of trophic cascade in specific terrestrial communities. A mesopredator is a medium-sized, middle trophic level predator, which both preys and is preyed upon.
MesopredatorA Mesopredator is a predator which occupies a mid-ranking trophic level in a food web. There is no standard definition of a mesopredator, but they are usually referred to as being medium-sized, compared to apex predators and the preys in the food web. Mesopredators typically prey on smaller animals. Mesopredators vary in different ecosystems depending on the food web. When new species are introduced into an ecosystem, the role of the mesopredator often changes; the same happens if species are removed.
