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Fahaka
The fahaka pufferfish (from ), also known as the Nile puffer, globe fish, lineatus puffer (''Tetraodon lineatus''), is a tropical freshwater pufferfish found in the upper Nile, Chad, Senegal, Gambia, Geba, Volta and Turkana basins in West, Northeast and East Africa. Characteristics Fahaka pufferfish can reach up to in length. They have the ability to inflate when threatened and, like many puffers, carry the toxin tetrodotoxin. Fahaka pufferfish, like other molluscivores, feed mainly on benthic organisms which may include freshwater mussels and snails. They are typically found in large rivers, open water, weed beds and vegetated fringes. In the River Nile, the recorded average lifespans of Fahaka pufferfish have measured about five years. Researchers AbouelFadl and Farrag have measured the gonadosomatic index of the Fahaka pufferfish to increase from April to August. They have interpreted these readings to suggest a spawning season during this period. Gallery File:Tet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetraodon
''Tetraodon'' is a genus in the pufferfish family (Tetraodontidae) found in freshwater in Africa. It is the type genus of the family and historically included numerous other species; several Asian species were moved to the genera '' Dichotomyctere'', '' Leiodon'' and '' Pao'' in 2013. Kottelat, M. (2013). The Fishes of the Inland Waters of Southeast Asia: A Catalogue and Core Bibliography of the Fishes Known to Occur in Freshwaters, Mangroves and Estuaries. ''The Raffles Bulletin of Zoology, 2013, Supplement No. 27: 1–663.''Eschmeyer, W. N., R. Fricke, and R. van der Laan (18 February 2017). Catalog of Fishes.' Retrieved 18 February 2017. Species There are 6 recognized species in this genus: * '' Tetraodon duboisi'' Poll, 1959 * ''Tetraodon lineatus'' Linnaeus, 1758 Events January–March * January 1 – Swedish biologist Carl Linnaeus (Carl von Linné) publishes in Stockholm the first volume (''Animalia'') of the 10th edition of ''Systema Naturae'', the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The IUCN Red List Of Threatened Species
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological species. A series of Regional Red Lists, which assess the risk of extinction to species within a political management unit, are also produced by countries and organizations. The goals of the Red List are to provide scientifically based information on the status of species and subspecies at a global level, to draw attention to the magnitude and importance of threatened biodiversity, to influence national and international policy and decision-making, and to provide information to guide actions to conserve biological diversity. Major species assessors include BirdLife International, the Institute of Zoology (the research division of the Zoological Society of London), the World Conservation Monitoring Centre, and many Specialist Groups within th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northeast Africa
Northeast Africa, or Northeastern Africa, or Northern East Africa as it was known in the past, encompasses the countries of Africa situated in and around the Red Sea. The region is intermediate between North Africa and East Africa, and encompasses the Horn of Africa (Djibouti, Eritrea, Ethiopia, and Somalia), as well as Egypt and Sudan, and in addition to, although rarely, South Sudan. The region has a very long history of habitation with fossil finds from the early hominids to modern human and is one of the most culturally and linguistically diverse regions of the world, being the home to many civilizations and located on an important trade route that connects multiple continents; Gamal Abdel Nasser, the second president of Egypt (which is the most northeastern African country) once described it as "the crossroads of the world, the thoroughfare of its traders and passageway of its armies." See also * East Africa * Horn of Africa * North Africa * Ancient Egypt * Ancient Libya * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spawn (biology)
Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of freely releasing eggs and sperm into a body of water (fresh or marine); the physical act is known as spawning. The vast majority of aquatic and amphibious animals reproduce through spawning. These include the following groups: * Bony fishes * Crustaceans (such as crabs, shrimps, etc.) *Mollusks (such as oysters, octopus, squid) *Echinoderms (such as sea urchins, sea stars, sea cucumbers, etc.) * Amphibians (such as frogs, toads, salamanders, newts) * Aquatic insects (such as dragonflies, mayflies, mosquitoes) *Coral, which are living colonies of tiny, aquatic organisms—not plants, as they are sometimes perceived to be. Corals, while appearing sedentary or botanical by nature, actually spawn by releasing clouds of sperm and egg cells into the water column, where the two mix. As a general rule, aquatic or semiaquatic reptiles, birds, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gonadosomatic Index
In biology, the gonadosomatic index (GSI) is the calculation of the gonad mass as a proportion of the total body mass. It is represented by the formula: GSI = onad weight / total tissue weight× 100 It is a tool for measuring the sexual maturity of animals in correlation to ovary development and testicle A testicle or testis ( testes) is the gonad in all male bilaterians, including humans, and is Homology (biology), homologous to the ovary in females. Its primary functions are the production of sperm and the secretion of Androgen, androgens, p ... development. The index is frequently used as reporting point in OECD test guideline, which may be used as indication or evidence of potential endocrine disruption effect of chemicals in regulatory framework (EFSA and ECHA, 2017). Guidance for the identification of endocrine disruptors in the context of Regulations (EU) no 528/2012 and (EC) 1107/2009. World Health Organization/ International Programme for Chemical Safety, 2002 Re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Life Expectancy
Human life expectancy is a statistical measure of the estimate of the average remaining years of life at a given age. The most commonly used measure is ''life expectancy at birth'' (LEB, or in demographic notation ''e''0, where ''e''x denotes the average life remaining at age ''x''). This can be defined in two ways. ''Cohort'' LEB is the mean length of life of a birth Cohort (statistics), cohort (in this case, all individuals born in a given year) and can be computed only for cohorts born so long ago that all their members have died. ''Period'' LEB is the mean length of life of a hypothetical cohort assumed to be exposed, from birth through death, to the mortality rates observed at a given year. National LEB figures reported by national agencies and international organizations for human populations are estimates of ''period'' LEB. Human remains from the early Bronze Age indicate an LEB of 24. In 2019, world LEB was 73.3. A combination of high infant mortality and d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snail
A snail is a shelled gastropod. The name is most often applied to land snails, terrestrial molluscs, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gastropoda that have a coiled gastropod shell, shell that is large enough for the animal to retract completely into. When the word "snail" is used in this most general sense, it includes not just land snails but also numerous species of sea snails and freshwater snails. Gastropods that naturally lack a shell, or have only an internal shell, are mostly called ''slugs'', and land snails that have only a very small shell (that they cannot retract into) are often called ''semi-slugs''. Snails have considerable human relevance, including Snails as food, as food items, as pests, and as vectors of disease, and their shells are used as decorative objects and are incorporated into jewellery. The snail has also had some cultural significance, tending t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mussels
Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which are often more or less rounded or oval. The word "mussel" is frequently used to mean the bivalves of the marine family Mytilidae, most of which live on exposed shores in the intertidal zone, attached by means of their strong byssal threads ("beard") to a firm substrate. A few species (in the genus '' Bathymodiolus'') have colonised hydrothermal vents associated with deep ocean ridges. In most marine mussels the shell is longer than it is wide, being wedge-shaped or asymmetrical. The external colour of the shell is often dark blue, blackish, or brown, while the interior is silvery and somewhat nacreous. The common name "mussel" is also used for many freshwater bivalves, including the freshwater pearl mussels. Freshwater mussel speci ... [...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 the Ancient Greek word (), 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, known as bottom dwellers, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molluscivore
A molluscivore is a carnivorous animal that specialises in feeding on molluscs such as gastropods, bivalves, brachiopods and cephalopods. Known molluscivores include numerous predatory (and often cannibalistic) molluscs, (e.g. octopuses, murexes, decollate snails and oyster drills), arthropods such as crabs and firefly larvae, and vertebrates such as fish, birds and mammals. Molluscivory is performed in a variety of ways with some animals highly adapted to this method of feeding. A similar behaviour, durophagy, describes the feeding of animals that consume hard-shelled or exoskeleton bearing organisms, such as corals, shelled molluscs, or crabs. Description Molluscivory can be performed in several ways: *In some cases, the mollusc prey are simply swallowed entire, including the shell, whereupon the prey is killed through suffocation and/or exposure to digestive enzymes. Only cannibalistic sea slugs, snail-eating cone shells of the taxon Coninae, and some sea anemones use th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrodotoxin
Tetrodotoxin (TTX) is a potent neurotoxin. Its name derives from Tetraodontiformes, an Order (biology), order that includes Tetraodontidae, pufferfish, porcupinefish, ocean sunfish, and triggerfish; several of these species carry the toxin. Although tetrodotoxin was discovered in these fish, it is found in several other animals (e.g., in blue-ringed octopus, blue-ringed octopuses, Taricha, rough-skinned newts, and Naticidae, moon snails). It is also produced by certain infectious or symbiotic bacteria like ''Pseudoalteromonas tetraodonis, Pseudoalteromonas'', ''Pseudomonas'', and ''Vibrio'' as well as other species found in symbiotic relationships with animals and plants. Although it produces thousands of intoxications annually and several deaths, it has shown efficacy for the treatment of cancer-related pain in phase II and III clinical trials. Tetrodotoxin is a sodium channel blocker. It inhibits the firing of action potentials in neurons by binding to the voltage-gated sodiu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
