Search results
Results from the WOW.Com Content Network
It covers 11.4 million square kilometres (4.38 million sq mi), which is the second largest zone in the world, exceeding the land area of the United States. [5] According to the FAO, in 2005, the United States harvested 4,888,621 tonnes of fish from wild fisheries, and another 471,958 tonnes from aquaculture. This made the United States the ...
The rate of production divided by the average amount of biomass that achieves it is known as an organism's Production/Biomass (P/B) ratio. [192] Production is measured in terms of the amount of movement of mass or energy per area per unit of time. In contrast, the biomass measurement is in units of mass per unit area or volume.
Energy in a system can be affected by animal emigration/immigration. The movements of organisms are significant in terrestrial ecosystems. [17] Energetic consumption by herbivores in terrestrial ecosystems has a low range of ~3-7%. [17] The flow of energy is similar in many terrestrial environments.
According to a 2019 FAO report, global production of fish, crustaceans, molluscs and other aquatic animals has continued to grow and reached 172.6 million tonnes in 2017, with an increase of 4.1 percent compared with 2016. [23] There is a growing gap between the supply of fish and demand, due in part to world population growth. [24]
Fish farming or pisciculture involves commercial breeding of fish, most often for food, in fish tanks or artificial enclosures such as fish ponds. It is a particular type of aquaculture , which is the controlled cultivation and harvesting of aquatic animals such as fish, crustaceans , molluscs and so on, in natural or pseudo-natural environments.
The organisms responsible for primary production are called primary producers or autotrophs. Most marine primary production is generated by a diverse collection of marine microorganisms called algae and cyanobacteria. Together these form the principal primary producers at the base of the ocean food chain and produce half of the world's oxygen ...
The mean trophic level is calculated by assigning each fish or invertebrate species a number based on its trophic level.The trophic level is a measure of the position of an organism in a food web, starting at level 1 with primary producers, such as phytoplankton and seaweed, then moving through the primary consumers at level 2 that eat the primary producers to the secondary consumers at level ...
Out of a total of 28,400 terawatt-hours (96.8 × 10 ^ 15 BTU) of energy used in the US in 1999, 10.5% was used in food production, [3] with the percentage accounting for food from both producer and primary consumer trophic levels. In comparing the cultivation of animals versus plants, there is a clear difference in magnitude of energy efficiency.