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Gulf Sturgeon
The Gulf sturgeon (''Acipenser oxyrinchus desotoi'') is a subspecies of sturgeon that lives in the Gulf of Mexico and some rivers draining into it. The Gulf sturgeon was first recognized as a separate subspecies in 1955. The nominate subspecies is the Atlantic sturgeon, ''A. o. oxyrinchus''. The Gulf sturgeon is listed as threatened under the United States Endangered Species Act, having been listed in 1991. Critical habitat, reflecting the current range of the subspecies, has been designated (see map). The historical range is thought to have been from the Suwannee River on the western coast of Florida to the Mississippi River, and marine waters of the central and eastern portions of the Gulf of Mexico. Three sturgeon species in genus ''Scaphirhynchus'' share river territory with the Gulf sturgeon; none of these is anadromous.U.S. Fish and Wildlife Service and Gulf States Marine Fisheries Commission. 1995. ''Gulf Sturgeon Recovery Plan''. Atlanta, Georgia. Physica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vadim Dimitrievitch Vladykov
Vadim (Cyrillic script, Cyrillic: Вадим) is a Russian, Ukrainian, Romanian, Slovene masculine given name derived either from the Persian ''badian'' (anise or aniseed), or from the Ruthenian word ''volod'' (russian: волод), meaning ''to rule'' or ''vaditi'' (russian: вадити), meaning ''to blame''. Its long version, Vadimir, is now obsolete. Dictionary of Russian Names This given name is highly popular in Russia (as Vadim), Ukraine (as Vadym), Belarus (as Vadzim), Moldova, and Slovenia. Given name *Bademus or Vadim (died 376), Persian martyr and saint widely venerated in the Eastern Orthodox Church *Vadim the Bold legendary chieftain *Vadim Abdrashitov (born 1945), Russian film director *Vadim Alekseyev (born 1970), Soviet-I ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pectoral Fin
Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as seen in sharks. Apart from the tail or caudal fin, fish fins have no direct connection with the spine and are supported only by muscles. Their principal function is to help the fish swim. Fins located in different places on the fish serve different purposes such as moving forward, turning, keeping an upright position or stopping. Most fish use fins when swimming, flying fish use pectoral fins for gliding, and frogfish use them for crawling. Fins can also be used for other purposes; male sharks and mosquitofish use a modified fin to deliver sperm, thresher sharks use their caudal fin to stun prey, reef stonefish have spines in their dorsal fins that inject venom, anglerfish use the first spine of their dorsal fin like a fishing rod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundwater
Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from the surface; it may discharge from the surface naturally at springs and seeps, and can form oases or wetlands. Groundwater is also often withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction wells. The study of the distribution and movement of groundwater is hydrogeology, also called groundwater hydrology. Typically, groundwater is thought of as water flowing through shallow aquifers, but, in the technical sense, it can also contain soil moisture, permafros ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spring (hydrosphere)
A spring is a point of exit at which groundwater from an aquifer flows out on top of Earth's crust ( pedosphere) and becomes surface water. It is a component of the hydrosphere. Springs have long been important for humans as a source of fresh water, especially in arid regions which have relatively little annual rainfall. Springs are driven out onto the surface by various natural forces, such as gravity and hydrostatic pressure. Their yield varies widely from a volumetric flow rate of nearly zero to more than for the biggest springs. Formation Springs are formed when groundwater flows onto the surface. This typically happens when the groundwater table reaches above the surface level. Springs may also be formed as a result of karst topography, aquifers, or volcanic activity. Springs also have been observed on the ocean floor, spewing hot water directly into the ocean. Springs formed as a result of karst topography create karst springs, in which ground water travels throu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Migration
Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres. Such migrations are usually done for better feeding or to reproduce, but in other cases the reasons are unclear. Fish migrations involve movements of schools of fish on a scale and duration larger than those arising during normal daily activities. Some particular types of migration are ''anadromous'', in which adult fish live in the sea and migrate into fresh water to spawn; and ''catadromous'', in which adult fish live in fresh water and migrate into salt water to spawn. Marine forage fish often make large migrations between their spawning, feeding and nursery grounds. Movements are associated with ocean currents and with the availability of food in different areas at different times of year. The migratory movements m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphipoda
Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far described. They are mostly marine animals, but are found in almost all aquatic environments. Some 1,900 species live in fresh water, and the order also includes the terrestrial sandhoppers such as '' Talitrus saltator''. Etymology and names The name ''Amphipoda'' comes, via New Latin ', from the Greek roots 'on both/all sides' and 'foot'. This contrasts with the related Isopoda, which have a single kind of thoracic leg. Particularly among anglers, amphipods are known as ''freshwater shrimp'', ''scuds'', or ''sideswimmers''. Description Anatomy The body of an amphipod is divided into 13 segments, which can be grouped into a head, a thorax and an abdomen. The head is fused to the thorax, and bears two pairs of antennae and one pair of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isopoda
Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in fresh water, or on land. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, and five pairs of branching appendages on the abdomen that are used in respiration. Females brood their young in a pouch under their thorax. Isopods have various feeding methods: some eat dead or decaying plant and animal matter, others are grazers, or filter feeders, a few are predators, and some are internal or external parasites, mostly of fish. Aquatic species mostly live on the seabed or bottom of freshwater bodies of water, but some taxa can swim for a short distance. Terrestrial forms move around by crawling and tend to be found in cool, moist places. Some species are able to roll themselves into a ball as a defense mechanism or to conserve moisture. There are over 10,000 identified species of isopod worldwide, with around 4 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grass Shrimp
''Palaemonetes'', its common names include glass shrimp, ghost shrimp, feeder shrimp, is a genus of caridean shrimp comprising a geographically diverse group of fresh water, brackish and marine crustaceans. Conventionally, ''Palaemonetes'' included the following species: *''Palaemonetes africanus'' Balss, 1916 *''Palaemonetes antennarius'' (H. Milne-Edwards, 1837) *''Palaemonetes antrorum'' Benedict, 1896 *''Palaemonetes argentinus'' Nobili, 1901 *''Palaemonetes atrinubes'' Bray, 1976 *''Palaemonetes australis'' Dakin, 1915 *''Palaemonetes camranhi'' Nguyên, 1997 *''Palaemonetes carteri'' Gordon, 1935 *''Palaemonetes cummingi'' Chace, 1954 *''Palaemonetes hiltoni'' Schmitt, 1921 *''Palaemonetes hobbsi'' Strenth, 1994 *''Palaemonetes intermedius'' Holthuis, 1949 *''Palaemonetes ivonicus'' Holthuis, 1950 *''Palaemonetes kadiakensis'' Rathbun, 1902 *''Palaemonetes karukera'' Carvacho, 1979 *''Palaemonetes lindsayi'' Villalobos Figueroa & H. H. Hobbs Jr., 1974 *''Palaemonetes merce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benthic
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "the depths." Organisms living in this zone are called benthos and include microorganisms (e.g., bacteria and fungi) as well as larger invertebrates, such as crustaceans and polychaetes. Organisms here generally live in close relationship with the substrate and many are permanently attached to the bottom. The benthic boundary layer, which includes the bottom layer of water and the uppermost layer of sediment directly influenced by the overlying water, is an integral part of the benthic zone, as it greatly influences the biological activity that takes place there. Examples of contact soil layers include sand bottoms, rocky outcrops, coral, and bay mud. Description Oceans The benthic region of the ocean begins at the shore line ( intert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paralytic Shellfish Poisoning
Paralytic shellfish poisoning (PSP) is one of the four recognized syndromes of shellfish poisoning, which share some common features and are primarily associated with bivalve mollusks (such as mussels, clams, oysters and scallops). These shellfish are filter feeders and accumulate neurotoxins, chiefly saxitoxin, produced by microscopic algae, such as dinoflagellates, diatoms, and cyanobacteria. Dinoflagellates of the genus ''Alexandrium'' are the most numerous and widespread saxitoxin producers and are responsible for PSP blooms in subarctic, temperate, and tropical locations. The majority of toxic blooms have been caused by the morphospecies ''Alexandrium catenella, Alexandrium tamarense'', '' Gonyaulax catenella'' and '' Alexandrium fundyense'', which together comprise the ''A. tamarense'' species complex. In Asia, PSP is mostly associated with the occurrence of the species ''Pyrodinium bahamense''. Some pufferfish, including the chamaeleon puffer, also contain saxitoxin, maki ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusca
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant taxon, extant species of molluscs are recognized. The number of fossil species is estimated between 60,000 and 100,000 additional species. The proportion of undescribed species is very high. Many taxa remain poorly studied. Molluscs are the largest marine biology, marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater mollusc, freshwater and Terrestrial molluscs, terrestrial habitats. They are highly diverse, not just in size and anatomical structure, but also in behaviour and habitat. The phylum is typically divided into 7 or 8 Taxonomy (biology), taxonomic class (biology), classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most neurobiology, neurologically advanced of all inve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brackish Water
Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root '' brak''. Certain human activities can produce brackish water, in particular civil engineering projects such as dikes and the flooding of coastal marshland to produce brackish water pools for freshwater prawn farming. Brackish water is also the primary waste product of the salinity gradient power process. Because brackish water is hostile to the growth of most terrestrial plant species, without appropriate management it is damaging to the environment (see article on shrimp farms). Technically, brackish water contains between 0.5 and 30 grams of salt per litre—more often expressed as 0.5 to 30 parts per thousand (‰), which is a specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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