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Mangrove Whipray
The mangrove whipray (''Urogymnus granulatus'') or whitetail stingray, is a species of stingray in the family (biology), family Dasyatidae. It is widely distributed in the Indo-Pacific region from the Red Sea to northern Australia and Micronesia. A benthic fish, benthic inhabitant of shallow inshore waters, juvenile mangrove whiprays favor mangrove and estuary, estuarine habitats, while adults favor sandy to rocky areas in lagoons and coral reefs. This species can be identified by its thick, oval pectoral fin disc that is dark gray above with numerous white flecks, and by its relatively short, whip-like tail that is white past the stinging spine. It grows up to across. Solitary in nature, the mangrove whipray preys mainly on small, benthic, bottom-dwelling bony fishes and invertebrates. It is, like other stingrays, aplacental viviparous, with the females nourishing their unborn young via histotroph ("uterine milk"). The mangrove whipray is caught for its meat, shagreen, skin, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William John Macleay
Sir William John Macleay (13 June 1820 – 7 December 1891) was a Scottish-Australian politician, Natural history, naturalist, zoologist, and Herpetology, herpetologist. Early life Macleay was born at Wick, Highland, Wick, Caithness, Scotland, second son of Kenneth Macleay of Keiss and his wife Barbara, ''née'' Horne. Macleay was educated at the Edinburgh Academy 1834–36 and then to studied medicine at the University of Edinburgh; but when he was 18 years old his widowed mother died, and he decided to go to Australia with his cousin, William Sharp MacLeay. They arrived at Sydney in March 1839 on HMS Royal George (1827), HMS ''Royal George''. William Macleay took up land at first near Goulburn, New South Wales, Goulburn, and afterwards on the Murrumbidgee River. He is noted as the last of the naturalists in a family active in this field; his uncle was Alexander Macleay, Colonial Secretary of New South Wales from 1826 to 1836, and a member and fellow of societies concerned wit ... [...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] |
Commercial Fishing
Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often pursue fish far into the ocean under adverse conditions. Large-scale commercial fishing is also known as industrial fishing. The major fishing industries are not only owned by major corporations but by small families as well. In order to adapt to declining fish populations and increased demand, many commercial fishing operations have reduced the sustainability of their harvest by fishing further down the food chain. This raises concern for fishery managers and researchers, who highlight how further they say that for those reasons, the sustainability of the marine ecosystems could be in danger of collapsing. Commercial fishermen harvest a wide variety of animals. However, a very small number of species support the majority of the world ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artisan Fishing
Artisanal fishing (or traditional/subsistence fishing) consists of various small-scale, low-technology, low-capital, fishing practices undertaken by individual fishing households (as opposed to commercial fishing). Many of these households are of coastal or island ethnic groups. These households make short (rarely overnight) fishing trips close to the shore. Their produce is usually not processed and is mainly for local consumption. Artisan fishing uses traditional fishing techniques such as rod and tackle, fishing arrows and harpoons, cast nets, and small (if any) traditional fishing boats. For that reason, socio-economic status of artisanal fishing community has become an interest of the authorities in recent years. Artisan fishing may be undertaken for both commercial and subsistence reasons. It contrasts with large-scale modern commercial fishing practices in that it is often less wasteful and less stressful on fish populations than modern industrial fishing. Target 14.b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southeast Asia
Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consisting of the regions that are situated south of mainland China, east of the Indian subcontinent, and north-west of mainland Australia. Southeast Asia is bordered to the north by East Asia, to the west by South Asia and the Bay of Bengal, to the east by Oceania and the Pacific Ocean, and to the south by Australia (continent), Australia and the Indian Ocean. Apart from the British Indian Ocean Territory and two out of atolls of Maldives, 26 atolls of Maldives in South Asia, Maritime Southeast Asia is the only other subregion of Asia that lies partly within the Southern Hemisphere. Mainland Southeast Asia is completely in the Northern Hemisphere. East Timor and the southern portion of Indonesia are the only parts that are south of the Equator. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endangered
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and invasive species. The International Union for Conservation of Nature (IUCN) Red List lists the global conservation status of many species, and various other agencies assess the status of species within particular areas. Many nations have laws that protect conservation-reliant species which, for example, forbid hunting, restrict land development, or create protected areas. Some endangered species are the target of extensive conservation efforts such as captive breeding and habitat restoration. Human activity is a significant cause in causing some species to become endangered. Conservation status The conservation status of a species indicates the likelihood that it will become extinct. Multiple factors are considered when assessing the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vulnerable Species
A vulnerable species is a species which has been Conservation status, categorized by the International Union for Conservation of Nature as being threatened species, threatened with extinction unless the circumstances that are threatened species, threatening its survival and reproduction improve. Vulnerability is mainly caused by habitat loss or destruction of the species' home. Vulnerable habitat or species are monitored and can become increasingly threatened. Some species listed as "vulnerable" may be common in captivity (animal), captivity, an example being the military macaw. There are currently 5196 animals and 6789 plants classified as Vulnerable, compared with 1998 levels of 2815 and 3222, respectively. Practices such as cryoconservation of animal genetic resources have been enforced in efforts to conserve vulnerable breeds of livestock specifically. Criteria The International Union for Conservation of Nature uses several criteria to enter species in this category. A tax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Union For Conservation Of Nature
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natural resources. It is involved in data gathering and analysis, research, field projects, advocacy, and education. IUCN's mission is to "influence, encourage and assist societies throughout the world to conserve nature and to ensure that any use of natural resources is equitable and ecologically sustainable". Over the past decades, IUCN has widened its focus beyond conservation ecology and now incorporates issues related to sustainable development in its projects. IUCN does not itself aim to mobilize the public in support of nature conservation. It tries to influence the actions of governments, business and other stakeholders by providing information and advice and through building partnerships. The organization is best known to the wider pu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shark Cartilage
Shark cartilage is a dietary supplement made from the dried and powdered cartilage of a shark; that is, from the tough material that composes a shark's skeleton. Shark cartilage is marketed under a variety of brand names, including Carticin, Cartilade, or BeneFin, and is marketed explicitly or implicitly as a treatment or preventive for various illnesses, including cancer. There is no scientific evidence that shark cartilage is useful in treating or preventing cancer or other diseases. Controlled trials have shown no benefit to shark cartilage supplements, and shark cartilage contains potentially toxic compounds linked to Alzheimer's disease and amyotrophic lateral sclerosis. However, shark cartilage supplements are still marketed using the misconception that sharks do not get cancer, a myth that was as popularized by the 1992 book ''Sharks Don't Get Cancer''. In the United States, the Federal Trade Commission has taken legal action against such fraudulent promoters. Tumors of m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shagreen
Shagreen is a type of rawhide consisting of rough untanned skin, historically from a horse's or onager's back, or from shark or ray. Etymology The word derives from the French ''chagrin'' and is related to Italian ''zigrino'' and Venetian ''sagrin'', derived from the Turkic ''sağrı'' / ''çağrı'' 'rump of a horse' or the prepared skin of this part. The roughness of its texture led to the French meaning of anxiety, vexation, embarrassment, or annoyance. Preparation and uses Shagreen has an unusually rough and granular surface, and is sometimes used as a fancy leather for book bindings, pocketbooks and small cases, as well as its more utilitarian uses in the hilts and scabbards of swords and daggers, where slipperiness is a disadvantage. In Asia, the Japanese tachi, katana, and wakizashi swords had their hilts almost always covered in undyed rawhide shagreen, while in China, shagreen, whose use dates back to the 2nd century CE, was traditionally used on Qing dynasty c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Histotroph
Uterine glands or endometrial glands are tubular glands, lined by ciliated columnar epithelium, found in the functional layer of the endometrium that lines the uterus. Their appearance varies during the menstrual cycle. During the proliferative phase, uterine glands appear long due to estrogen secretion by the ovaries. During the secretory phase, the uterine glands become very coiled with wide lumens and produce a glycogen-rich secretion known as ''histotroph'' or ''uterine milk''. This change corresponds with an increase in blood flow to spiral arteries due to increased progesterone secretion from the corpus luteum. During the pre-menstrual phase, progesterone secretion decreases as the corpus luteum degenerates, which results in decreased blood flow to the spiral arteries. The functional layer of the uterus containing the glands becomes necrotic, and eventually sloughs off during the menstrual phase of the cycle. They are of small size in the unimpregnated uterus, but shortly aft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aplacental Viviparous
Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop inside eggs that remain in the mother's body until they are ready to hatch. The young of some ovoviviparous amphibians, such as ''Limnonectes larvaepartus'', are born as larvae, and undergo further metamorphosis outside the body of the mother. Members of genera ''Nectophrynoides'' and ''Eleutherodactylus'' bear froglets, not only the hatching, but all the most conspicuous metamorphosis, being completed inside the body of the mother before birth. Among insects that depend on opportunistic exploitation of transient food sources, such as many Sarcophagidae and other carrion flies, and species such as many Calliphoridae, that rely on fresh dung, and parasitoids such as tachinid flies that depend on entering the host as soon as possible, the embr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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