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Ichthyoplankton
Ichthyoplankton (from Greek: ἰχθύς, , "fish"; and πλαγκτός, , "drifter") are the eggs and larvae of fish. They are mostly found in the sunlit zone of the water column, less than 200 metres deep, which is sometimes called the epipelagic or photic zone. Ichthyoplankton are planktonic, meaning they cannot swim effectively under their own power, but must drift with the ocean currents. Fish eggs cannot swim at all, and are unambiguously planktonic. Early stage larvae swim poorly, but later stage larvae swim better and cease to be planktonic as they grow into juveniles. Fish larvae are part of the zooplankton that eat smaller plankton, while fish eggs carry their own food supply. Both eggs and larvae are themselves eaten by larger animals. Fish can produce high numbers of eggs which are often released into the open water column. Fish eggs typically have a diameter of about . The newly hatched young of oviparous fish are called larvae. They are usually poorly formed, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Egg Diagram (1)
A fish (: fish or fishes) is an aquatic, anamniotic, gill-bearing vertebrate animal with swimming fins and a hard skull, but lacking limbs with digits. Fish can be grouped into the more basal jawless fish and the more common jawed fish, the latter including all living cartilaginous and bony fish, as well as the extinct placoderms and acanthodians. In a break to the long tradition of grouping all fish into a single class (Pisces), modern phylogenetics views fish as a paraphyletic group. Most fish are cold-blooded, their body temperature varying with the surrounding water, though some large active swimmers like white shark and tuna can hold a higher core temperature. Many fish can communicate acoustically with each other, such as during courtship displays. The study of fish is known as ichthyology. The earliest fish appeared during the Cambrian as small filter feeders; they continued to evolve through the Paleozoic, diversifying into many forms. The earliest fish wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Stocks
Fish stocks are population, subpopulations of a particular species of fish, for which intrinsic parameters (growth, recruitment, mortality and fishing mortality) are traditionally regarded as the significant factors determining the Population dynamics of fisheries, stock's population dynamics, while extrinsic factors (immigration and emigration) are traditionally ignored. Stocks fished within biologically sustainable levels decreased from 90% in 1974 to 62.3% in 2021. Concepts The stock concept All species have geographic limits to their distribution, which are determined by their Physiological tolerance, tolerance to natural environment, environmental conditions, and their ability to competition, compete successfully with other species. In ocean, marine environments this may be less evident than on land because there are fewer topography, topographical boundaries, however, discontinuities still exist, produced for example by mesoscale and sub-mesoscale circulations that m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MOCNESS
The MOCNESS (acronym for ''Multiple Opening/Closing Net and Environmental Sensing System'') is a towed net system for plankton and particles in the ocean. Consisting of 5-20 nets of variable mesh sizes, it is useful for collecting samples at multiple depths and sizes. Design and usage The system is towed behind a research vessel with a speed of up to and consists of five to twenty nets with a mesh size from 64 μm to 3 mm and an area of 0.25 to 20 m2 (although the last one is a 2x10 m systems) which are opened and closed computer controlled at desired depth. The net enables biologists to catch zooplankton and nekton in various depth horizons typically anywhere in the upper 6000 m of the oceans. All MOCNESS systems are capable of sampling to 6000 meters depth (10,000 psi). The system includes SeaBird probes to measure salinity and temperature at sampling depths, as well as optional dissolved oxygen, PAR (photosynthetically available light), transmissometry and fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bongo Drum
Bongos ( Spanish: ''bongó'') are an Afro-Cuban percussion instrument consisting of a pair of small open bottomed hand drums of different sizes. The pair consists of the larger ''hembra'' () and the smaller ''macho'' (), which are joined by a wooden bridge. They are played with both hands and usually held between the legs, although in some cases, as in classical music, they may be played with sticks or mounted on stands. Bongos are mainly employed in the rhythm section of son cubano and salsa ensembles, often alongside other drums such as the larger congas and the stick-struck timbales. In these groups, the bongo player is known as ''bongosero'' and often plays a continuous eight-stroke pattern called ''martillo'' () as well as more rhythmically free parts, providing improvisatory flourishes and rhythmic counterpoint. Bongos originated in eastern Cuba at the end of the 19th century, possibly from a pair of larger drums such as the bokú. These older, larger bongos are known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neuston
Neuston, also called pleuston, are organisms that live at the surface of a body of water, such as an ocean, estuary, lake, river, wetland or pond. Neuston can live on top of the water surface or submersed just below the water surface. In addition, microorganisms can exist in the surface microlayer that forms between the top- and the under-side of the water surface. Neuston has been defined as "organisms living at the air/water interface of freshwater, estuarine, and marine habitats or referring to the biota on or directly below the water’s surface layer." Neustons can be informally separated into two groups: the phytoneuston, which are autotrophs floating at the water surface including cyanobacteria, filamentous algae and free-floating aquatic plant (e.g. mosquito fern, duckweed and water lettuce); and the zooneuston, which are floating heterotrophs such as protists (e.g. ciliates) and metazoans (aquatic animals). This article mainly concerns with metazoan zooneustons. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Continuous Underway Fish Egg Sampler
Continuity or continuous may refer to: Mathematics * Continuity (mathematics), the opposing concept to discreteness; common examples include ** Continuous probability distribution or random variable in probability and statistics ** Continuous game, a generalization of games used in game theory ** Law of continuity, a heuristic principle of Gottfried Leibniz * Continuous function, in particular: ** Continuity (topology), a generalization to functions between topological spaces ** Scott continuity, for functions between posets ** Continuity (set theory), for functions between ordinals ** Continuity (category theory), for functors ** Graph continuity, for payoff functions in game theory * Continuity theorem may refer to one of two results: ** Lévy's continuity theorem, on random variables ** Kolmogorov continuity theorem, on stochastic processes * In geometry: ** Parametric continuity, for parametrised curves ** Geometric continuity, a concept primarily applied to the conic sec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Oceanic And Atmospheric Administration
The National Oceanic and Atmospheric Administration (NOAA ) is an American scientific and regulatory agency charged with Weather forecasting, forecasting weather, monitoring oceanic and atmospheric conditions, Hydrography, charting the seas, conducting deep-sea exploration, and managing fishing and protection of marine mammals and endangered species in the US exclusive economic zone. The agency is part of the United States Department of Commerce and is headquartered in Silver Spring, Maryland. History NOAA traces its history back to multiple agencies, some of which are among the earliest in the federal government: * United States Coast and Geodetic Survey, formed in 1807 * National Weather Service, Weather Bureau of the United States, formed in 1870 * United States Fish Commission, Bureau of Commercial Fisheries, formed in 1871 (research fleet only) * NOAA Commissioned Corps, Coast and Geodetic Survey Corps, formed in 1917 The most direct predecessor of NOAA was the Enviro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Research Vessel
A research vessel (RV or R/V) is a ship or boat designed, modified, or equipped to carry out research at sea. Research vessels carry out a number of roles. Some of these roles can be combined into a single vessel but others require a dedicated vessel. Due to the demanding nature of the work, research vessels may be constructed around an icebreaker hull, allowing them to operate in polar waters. History The research ship had origins in the early voyages of exploration. By the time of James Cook's ''Endeavour'', the essentials of what today we would call a research ship are clearly apparent. In 1766, the Royal Society hired Cook to travel to the Pacific Ocean to observe and record the transit of Venus across the Sun. The ''Endeavour'' was a sturdy vessel, well designed and equipped for the ordeals she would face, and fitted out with facilities for her "research personnel", Joseph Banks. As is common with contemporary research vessels, ''Endeavour'' also carried out more t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abundance (ecology)
In ecology, local abundance is the relative representation of a species in a particular ecosystem. It is usually measured as the number of individuals found per sample. The ratio of abundance of one species to one or multiple other species living in an ecosystem is referred to as relative species abundances. Both indicators are relevant for computing biodiversity. A variety of sampling methods are used to measure abundance. For larger animals, these may include spotlight counts, track counts and roadkill counts, as well as presence at monitoring stations. In many plant communities the abundances of plant species are measured by plant cover, i.e. the relative area covered by different plant species in a small plot. Abundance is in simplest terms usually measured by identifying and counting every individual of every species in a given sector. It is common for the distribution of species to be skewed so that a few species take up the bulk of individuals collected. Relative spe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantitative Research
Quantitative research is a research strategy that focuses on quantifying the collection and analysis of data. It is formed from a deductive approach where emphasis is placed on the testing of theory, shaped by empiricist and positivist philosophies. Associated with the natural, applied, formal, and social sciences this research strategy promotes the objective empirical investigation of observable phenomena to test and understand relationships. This is done through a range of quantifying methods and techniques, reflecting on its broad utilization as a research strategy across differing academic disciplines. There are several situations where quantitative research may not be the most appropriate or effective method to use: 1. When exploring in-depth or complex topics. 2. When studying subjective experiences and personal opinions. 3. When conducting exploratory research. 4. When studying sensitive or controversial topics The objective of quantitative research is to deve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norsk Biografisk Leksikon
is the largest Norwegian biographical encyclopedia. It is part of the '' Great Norwegian Encyclopedia''. Origin The first print edition (NBL1) was issued between 1923 and 1983; it included 19 volumes and 5,100 articles. Kunnskapsforlaget took over the rights to NBL1 from Aschehoug in 1995, and work began on a second print edition (NBL2) in 1998. The project had economic support from the Fritt Ord Foundation and the Ministry of Culture, and NBL2 was launched in the years 1999–2005, including 10 volumes and around 5,700 articles. Online access In 2009 an Internet The Internet (or internet) is the Global network, global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a internetworking, network of networks ... edition, with free access, was released by together with the general-purpose . The electronic edition features additional biographies, and updates about dates of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelagic
The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the surface of the sea and the bottom. Conditions in the water column change with depth: pressure increases; temperature and light decrease; salinity, oxygen, micronutrients (such as iron, magnesium and calcium) all change. In a manner analogous to stratification in the Earth's atmosphere, the water column can be divided vertically into up to five different layers (illustrated in the diagram), with the number of layers depending on the depth of the water. Marine life is affected by bathymetry (underwater topography) such as the seafloor, shoreline, or a submarine seamount, as well as by proximity to the boundary between the ocean and the atmosphere at the ocean surface, which brings light for photosynthesis, predation from above, and wind st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
