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95-583: There is a popular misconception that the name Nevėžis means "a river without crayfishes " because vėžys is the Lithuanian word for crayfish and ne means "no". In fact, the Nevėžis is known for its variety of fauna which include crayfish. Other ethimology suggested from Proto-Baltic * nevēźā- (ex. Lithuainian ne-vežti 'not to carry') and means 'slow, not-conveying river'. The Soviet-Belarusian geographer Vadim Zhuchkevich  [ ru ] suggested that

190-427: A crab, lobster, or prawn (shrimp), is made up of twenty body segments grouped into two main body parts, the cephalothorax and the abdomen . Each segment may possess one pair of appendages , although in various groups, these may be reduced or missing. On average, crayfish grow to 17.5 cm (6.9 in) in length. Walking legs have a small claw at the end. Crayfish are opportunistic omnivorous scavengers, with

285-458: A day-to-day basis, they consume what they can acquire in their immediate environment in limited space and time available - detritus . At a microbial level, the FPOM has a high surface area of organic particles and consists of a plethora of substrate and bacteria , fungi , micro-algae , meiofauna , partially decomposed organic material and mucus. This mucus or "slime" is a biofilm and can be felt on

380-457: A domestication of the wild rice Oryza rufipogon by cultures associated with pre-Austronesian and Hmong-Mien-speakers. This occurred 13,500 to 8,200 years ago south of the Yangtze River in present-day China. There are two likely centers of domestication for rice as well as the development of the wet-field technology. The first is in the lower Yangtze River , believed to be the homelands of

475-499: A dozen genera . It is home to the world's three largest freshwater crayfish: Many of the better-known Australian crayfish are of the genus Cherax , and include the common yabby ( C. destructor ), western yabby ( C. preissii ), and red-claw crayfish ( C. quadricarinatus ). The marron species C. tenuimanus is critically endangered , while other large Australasian crayfish are threatened or endangered. In New Zealand , two species of Paranephrops are endemic, and are known by

570-620: A family name. Many chose a name based on some geographical feature associated with their residence or occupation, and as nearly three-fourths of the population were farmers, many made family names using ta . Some common examples are Tanaka ( 田中 ), literally meaning "in the paddy field;" Nakata ( 中田 ), "middle paddy field;" Kawada (川田), "river paddy field;" and Furuta ( 古田 ), "old paddy field." In recent years, rice consumption in Japan has fallen and many rice farmers are increasingly elderly. The government has subsidized rice production since

665-553: A great deal of labor and materials to create and need large quantities of water for irrigation. Oxen and water buffalo , adapted for life in wetlands , are important working animals used extensively in paddy field farming. Paddy field farming remains the dominant form of growing rice in modern times. It is practiced extensively in Bangladesh , Cambodia , China , India , Indonesia , northern Iran , Japan , Laos , Malaysia , Mongolia , Myanmar , Nepal , North Korea , Pakistan ,

760-503: A greater understanding of the creatures. The Protivin brewery in the Czech Republic uses crayfish outfitted with sensors to detect any changes in their bodies or pulse activity in order to monitor the purity of the water used in their product. The creatures are kept in a fish tank that is fed with the same local natural source water used in their brewing. If three or more of the crayfish have changes to their pulses, employees know there

855-496: A newly irrigated paddy field, especially those made during or after the Edo period , may be called Nitta or Shinden (both 新田 ), "new paddy field." In some places, lakes and marshes were likened to a paddy field and were named with ta , like Hakkōda ( 八甲田 ). Today, many family names have ta as a component, a practice which can be largely attributed to a government edict in the early Meiji Period which required all citizens to have

950-532: A possible environmental and commercial solution. The word "paddy" is derived from the Malay / Indonesian word padi , meaning "rice plant", which is itself derived from Proto-Austronesian *pajay ("rice in the field", "rice plant"). Cognates include Amis panay ; Tagalog pálay ; Kadazan Dusun paai ; Javanese pari ; and Chamorro faʻi , among others. Genetic evidence shows that all forms of paddy rice, including both indica and japonica , spring from

1045-468: A sense, it has been unable to cope with population growth and other rice economies which utilized fertilizers. Rice is now grown in all the three seasons of Myanmar, though primarily in the Monsoon season – from June to October. Rice grown in the delta areas relies heavily on the river water and sedimented minerals from the northern mountains, whilst the rice grown in the central regions require irrigation from

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1140-452: A similar way to mammals. Then the stress hormone cortisol is released and this leads to the formation of lactic acid in the muscles, which makes the meat taste sour. Crayfish can be cooked more humanely by first freezing them unconscious for a few hours, then destroying the central nervous system along their abdomen by cutting the crayfish lengthwise with a long knife down the center of the crayfish before cooking it. Global crayfish production

1235-425: A small portion of the diet by volume. They feed on submerged vegetable material at times, but their ability to catch large living animal material is restricted. They can feed on interstitial organisms if they can be grasped in the small feeding claws. They can be lured into traps with an array of baits from dog biscuits, fish heads, meat, etc., all of which reinforces the fact that they are generalist feeders. On

1330-462: A variety of ray-finned fishes , and are commonly used as bait , either live or with only the tail meat. They are a popular bait for catching catfish , largemouth bass , smallmouth bass , striped bass , perch , pike and muskie . When using live crayfish as bait, anglers prefer to hook them between the eyes, piercing through their hard, pointed beak which causes them no harm; therefore, they remain more active. When using crayfish as bait, it

1425-598: Is a change in the water and examine the parameters. Scientists also monitor crayfish in the wild in natural bodies of water to study the levels of pollutants there. Paddy fields A paddy field is a flooded field of arable land used for growing semiaquatic crops, most notably rice and taro . It originates from the Neolithic rice-farming cultures of the Yangtze River basin in southern China, associated with pre-Austronesian and Hmong-Mien cultures. It

1520-629: Is a potential for ecological damage when crayfish are introduced into non-native bodies of water: e.g., crayfish plague in Europe, or the introduction of the common yabby ( Cherax destructor ) into drainages east of the Great Dividing Range in Australia. Some public schools in the United States keep live crayfish in the classroom and have the students take care of them in order to give the students

1615-669: Is archaeological evidence that unhusked rice was stored for the military and for burial with the deceased from the Neolithic period to the Han dynasty in China. By the late Neolithic (3500 to 2500 BC), population in the rice cultivating centers had increased rapidly, centered around the Qujialing - Shijiahe and Liangzhu cultures. There was also evidence of intensive rice cultivation in paddy fields as well as increasingly sophisticated material cultures in these two regions. The number of settlements among

1710-483: Is available, rice farmers typically plant Green Revolution rice varieties allowing three growing seasons per year. Since fertilizer and pesticide are relatively expensive inputs, farmers typically plant seeds in a very small plot. Three weeks following germination, the 15-20 centimetre (6–8 in) stalks are picked and replanted at greater separation, in a backbreaking manual procedure. Rice harvesting in Central Java

1805-464: Is caused by the North American water mold Aphanomyces astaci. This water mold was transmitted to Europe when North American species of crayfish were introduced. Species of the genus Astacus are particularly susceptible to infection, allowing the plague-coevolved signal crayfish (native to western North America) to invade parts of Europe . Acid rain can cause problems for crayfish across

1900-578: Is centered in Asia, primarily China. In 2018, Asian production accounted for 95% of the world's crawfish supply. Crayfish is part of Swedish cuisine and is usually eaten in August at special crayfish parties ( Swedish : Kräftskiva ). Documentation of the consumption of crayfish dates to at least the 16th century. On the Swedish west coast, Nephrops norvegicus ( Havskräfta , lit.   ' sea crayfish ' )

1995-643: Is considered the main rice growing province of the Philippines . The Banaue Rice Terraces are an example of paddy fields in the country. They are located in Banaue in Northern Luzon , Philippines and were built by the Ifugaos 2,000 years ago. Streams and springs found in the mountains were tapped and channeled into irrigation canals that run downhill through the rice terraces. Other notable Philippine paddy fields are

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2090-457: Is determined by the variety and quality control of water. The tavy is traditionally the culture of flooded upland rice on burning of cleared natural rain forest (135,966 ha). Criticized as being the cause of deforestation, tavy is still widely practiced by farmers in Madagascar, who find a good compromise between climate risks, availability of labour and food security. By extension,

2185-457: Is found in some place names, especially small farming townships and villages. However, the specific Korean term for 'paddy' is a purely Korean word, "non" ( Korean :  논 ). In Madagascar , the average annual consumption of rice is 130 kg per person, one of the largest in the world. According to a 1999 study of UPDRS / FAO: The majority of rice is related to irrigation (1,054,381 ha). The choice of methods conditioning performance

2280-731: Is found in the Pacific Northwest and the headwaters of some rivers east of the Continental Divide . Many crayfish are also found in lowland areas where the water is abundant in calcium , and oxygen rises from underground springs. Crayfish are also found in some non-coastal wetlands; eight species of crayfish live in Iowa , for example. In 1983, Louisiana designated the crayfish, or crawfish as they are commonly called, as its official state crustacean. Louisiana produces 100 million pounds (45 million kilograms) of crawfish per year with

2375-564: Is grown in Northern Italy, especially in the valley of the Po River . The paddy fields are irrigated by fast-flowing streams descending from the Alps . In the 19th century and much of the 20th century, the paddy fields were farmed by the mondine , a subculture of seasonal rice paddy workers composed mostly of poor women. The acidic soil conditions common in Japan due to volcanic eruptions have made

2470-532: Is important to fish in the same environment where they were caught. An Illinois State University report that focused on studies conducted on the Fox River and Des Plaines River watershed stated that rusty crayfish , initially caught as bait in a different environment, were dumped into the water and "outcompeted the native clearwater crayfish". Other studies confirmed that transporting crayfish to different environments has led to various ecological problems, including

2565-467: Is in the end phase of decomposition and is recognised as black organic mud. The crayfish usually ingest the material in only a few minutes, as distinct from grazing for many hours. The material is mixed with digestive fluids and sorted by size. The finer particles follow a slower and more exacting route through to the hindgut , compared to the coarser material. The coarser material is eliminated first and often reappears in approximately 10 to 12 hours, whereas

2660-480: Is more commonly eaten while various freshwater crayfish are consumed in the rest of the country. Prior to the 1960s, crayfish was largely inaccessible to the urban population in Sweden and consumption was largely limited to the upper classes or farmers holding fishing rights in fresh water lakes. With the introduction of import of frozen crayfish the crayfish party is now widely practiced across all spheres in Sweden and among

2755-542: Is often performed not by owners or sharecroppers of paddies, but rather by itinerant middlemen, whose small firms specialize in the harvest, transport, milling, and distribution of rice. The fertile volcanic soil of much of the Indonesian archipelago—particularly the islands of Java and Bali—has made rice a central dietary staple. Steep terrain on Bali resulted in complex irrigation systems, locally called subak , to manage water storage and drainage for rice terraces. Rice

2850-645: Is running, while others thrive in swamps , ditches, and paddy fields . Most crayfish cannot tolerate polluted water , although some species, such as Procambarus clarkii , are hardier. Crayfish feed on animals and plants, either living or decomposing , and detritus . The term "crayfish" is applied to saltwater species in some countries . The name "crayfish" comes from the Old French word escrevisse ( Modern French écrevisse ). The word has been modified to "crayfish" by association with "fish" ( folk etymology ). The largely American variant "crawfish"

2945-483: Is similarly derived. Some kinds of crayfish are known locally as lobsters , crawdads, mudbugs, and yabbies . In the Eastern United States , "crayfish" is more common in the north, while "crawdad" is heard more in central and southwestern regions, and "crawfish" farther south, although considerable overlaps exist. The study of crayfish is called astacology. The body of a decapod crustacean , such as

Nevėžis - Misplaced Pages Continue

3040-606: Is the largest in the world, only about 15% of its total land area can be cultivated. About 75% of the cultivated area is used for food crops. Rice is China's most important crop, raised on about 25% of the cultivated area. Most rice is grown south of the Huai River , in the Yangtze valley, the Zhu Jiang delta, and in Yunnan , Guizhou , and Sichuan provinces. Rice appears to have been used by

3135-465: Is unique because it breeds and tries to protect from extinction wisents , the European bison. Even with two canals supplying Nevėžis with water, it becomes very shallow during a drier summer. Regularly it is between 4 and 9 meters deep. In more recent years, a number of grass carp was introduced to the river for aquatic weed control. The Nevėžis, due to its low level of water, slow current, and influx of

3230-855: The Comoros , and the coast of East Africa around the 1st millennium AD by Austronesian settlers from the Greater Sunda Islands . There are ten archaeologically excavated rice paddy fields in Korea. The two oldest are the Okhyun and Yaumdong sites, found in Ulsan , dating to the early Mumun pottery period . Paddy field farming goes back thousands of years in Korea. A pit-house at the Daecheon-ni site yielded carbonized rice grains and radiocarbon dates, indicating that rice cultivation in dry-fields may have begun as early as

3325-526: The Irrawaddy River . The fields are tilled when the first rains arrive – traditionally measured at 40 days after Thingyan , the Burmese New Year – around the beginning of June. In modern times, tractors are used, but traditionally, buffalos were employed. The rice plants are planted in nurseries and then transplanted by hand into the prepared fields. The rice is then harvested in late November – "when

3420-613: The Italian agile frog and the painted frog in Malta . Crayfish are eaten worldwide. Like other edible crustaceans, only a small portion of the body of a crayfish is eaten. In most prepared dishes, such as soups, bisques and étouffées , only the tail portion is served. At crawfish boils or other meals where the entire body of the crayfish is presented, other portions, such as the claw meat, may be eaten. Research shows that crayfish do not die immediately when boiled alive, and respond to pain in

3515-618: The Late Triassic (~230-200 million years ago) Chinle Formation of North America, assigned to the species " Enoploclytia " porteri and Camborygma eumekenomos, which are not assigned to any modern families. An indeterminate member of the modern family Cambaridae is known from the Late Jurassic Morrison Formation of North America. The earliest records of other modern families date to the Early Cretaceous, including

3610-641: The Lėvuo river, the Sanžilė Canal was dug in 1930. A draft to connect these rivers was first written in 1797. The location was very convenient: about 9,000 years ago Nevėžis was a tributary to Lėvuo. The land between the rivers was low and there was a small Sanžilė rivulet which could serve as the basis for the new canal. In the 19th century the Neman delta belonged to the Germans. This was an obstacle in trading. The Russian Empire

3705-611: The Malaysian Peninsula , with most of the fields being located in the northern states such as Kedah , Perlis , Perak , and Penang . Paddy fields can also be found on Malaysia's east coast region, in Kelantan and Terengganu . The central state of Selangor also has its fair share of paddy fields, especially in the districts of Kuala Selangor and Sabak Bernam . Before Malaysia became heavily reliant on its industrial output, people were mainly involved in agriculture, especially in

3800-531: The Māori name kōura . In Australia, New Zealand, and South Africa , the term "crayfish" or "cray" generally refers to a saltwater spiny lobster , of the genus Jasus that is indigenous to much of southern Oceania , while the freshwater species are usually called yabbies or kōura , from the indigenous Australian and Māori names for the animal, respectively, or by other names specific to each species. Exceptions include western rock lobster (of

3895-557: The National Park Service as well as video and anecdotal reports by aquarium owners indicate that crayfish will eat their moulted exoskeleton "to recover the calcium and phosphates contained in it." As omnivores, crayfish will eat almost anything; therefore, they may explore the edibility of aquarium plants in a fish tank. However, most species of dwarf crayfish, such as Cambarellus patzcuarensis , will not destructively dig or eat live aquarium plants. In some nations, such as

Nevėžis - Misplaced Pages Continue

3990-584: The Northern Hemisphere and one in the Southern Hemisphere . The Southern Hemisphere ( Gondwana -distributed) family Parastacidae , with 14 extant genera and two extinct genera, live(d) in South America , Madagascar , and Australasia . They are distinguished by the absence of the first pair of pleopods . Of the other three Northern Hemisphere families (grouped in the superfamily Astacoidea ),

4085-666: The Palinuridae family) found on the west coast of Australia (it is a spiny lobster, but not of Jasus) ; the Tasmanian giant freshwater crayfish (from the Parastacidae family and therefore a true crayfish) found only in Tasmania; and the Murray crayfish found along Australia's Murray River . In Singapore , the term crayfish typically refers to Thenus orientalis , a seawater crustacean from

4180-863: The Philippines , South Korea , Sri Lanka , Taiwan , Thailand , and Vietnam . It has also been introduced elsewhere since the colonial era, notably in northern Italy , the Camargue in France , and in Spain , particularly in the Albufera de València wetlands in the Valencian Community , the Ebro Delta in Catalonia and the Guadalquivir wetlands in Andalusia , as well as along

4275-541: The Philippines , bringing rice cultivation technologies with them. From Luzon, Austronesians rapidly colonized the rest of Maritime Southeast Asia , moving westwards to Borneo , the Malay Peninsula and Sumatra ; and southwards to Sulawesi and Java . By 500 BC, there is evidence of intensive wetland rice agriculture already established in Java and Bali , especially near very fertile volcanic islands. Rice did not survive

4370-579: The Spring and Autumn period (722–481 BC), two revolutionary improvements in farming technology took place. One was the use of cast iron tools and beasts of burden to pull plows, and the other was the large-scale harnessing of rivers and development of water conservation projects. Sunshu Ao of the 6th century BC and Ximen Bao of the 5th century BC are two of the earliest hydraulic engineers from China, and their works were focused upon improving irrigation systems. These developments were widely spread during

4465-661: The Swedish-speaking population of Finland . In the United States, crayfish production is strongly centered in Louisiana , with 93% of crayfish farms located in the state as of 2018. In 1987, Louisiana produced 90% of the crayfish harvested in the world, 70% of which were consumed locally. In 2007, the Louisiana crayfish harvest was about 54,800 tons, almost all of it from aquaculture . About 70–80% of crayfish produced in Louisiana are Procambarus clarkii (red swamp crawfish), with

4560-480: The United Kingdom , United States , Australia , and New Zealand , imported alien crayfish are a danger to local rivers. The three most widespread American species invasive in Europe are Faxonius limosus , Pacifastacus leniusculus and Procambarus clarkii . Crayfish may spread into different bodies of water because specimens captured for pets in one river are often released into a different catchment. There

4655-638: The parastacid Palaeoechinastacus from Australia which is 115 million years old, the cambaroidid Palaeocambarus from the Yixian Formation of China which is likely around 120 million years old ( Barremian - Aptian ), and the astacid " Austropotamobius " llopisi from the Las Hoyas site in Spain (Barremian). Crayfish are susceptible to infections such as crayfish plague and to environmental stressors including acidification. In Europe, they are particularly threatened by crayfish plague, which

4750-447: The red swamp and white river crawfish being the main species harvested. Crawfish are a part of Cajun culture dating back hundreds of years. A variety of cottage industries have developed as a result of commercialized crawfish iconography. Their products include crawfish attached to wooden plaques, T-shirts with crawfish logos, and crawfish pendants, earrings, and necklaces made of gold or silver. Australia has over 100 species in

4845-512: The slipper lobster family. True crayfish are not native to Singapore, but are commonly found as pets, or as an invasive species ( Cherax quadricarinatus ) in the many water catchment areas, and are alternatively known as freshwater lobsters . In the United Kingdom and Ireland, the terms crayfish or crawfish commonly refer to the European spiny lobster , a saltwater species found in much of

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4940-523: The tanety , which literally means "hill," is also growing upland rice, carried out on the grassy slopes that have been deforested for the production of charcoal (139,337 ha). Among the many varieties, rice of Madagascar includes: Vary lava - a translucent long and large grain rice, considered a luxury rice; Vary Makalioka - a translucent long and thin grain rice; Vary Rojofotsy - a half-long grain rice; and Vary mena , or red rice, exclusive to Madagascar. Paddy fields can be found in most states on

5035-504: The 1970s, and favors protectionist policies regarding cheaper imported rice. Arable land in small alluvial flats of most rural river valleys in South Korea are dedicated to paddy-field farming. Farmers assess paddy fields for any necessary repairs in February. Fields may be rebuilt, and bund breaches are repaired. This work is carried out until mid-March, when warmer spring weather allows

5130-641: The Austronesian voyages into Micronesia and Polynesia ; however, wet-field agriculture was transferred to the cultivation of other crops, most notably for taro cultivation. The Austronesian Lapita culture also came into contact with the non-Austronesian ( Papuan ) early agriculturists of New Guinea and introduced wetland farming techniques to them. In turn, they assimilated their range of indigenous cultivated fruits and tubers before spreading further eastward to Island Melanesia and Polynesia . Rice and wet-field agriculture were also introduced to Madagascar ,

5225-613: The Early Neolithic populations of Lijiacun and Yunchanyan in China. Evidence of possible rice cultivation from ca. 11,500 BC has been found, however it is still questioned whether the rice was indeed being cultivated, or instead being gathered as wild rice. Bruce Smith, an archaeologist at the Smithsonian Institution in Washington, D.C., who has written on the origins of agriculture, says that evidence has been mounting that

5320-569: The Early Mumun pottery period (c. 1100–850 BC). KUM has conducted excavations, that have revealed similarly dated paddy field features, at Yaeum-dong and Okhyeon, in modern-day Ulsan . The earliest Mumun features were usually located in low-lying narrow gullies, that were naturally swampy and fed by the local stream system. Some Mumun paddy fields in flat areas were made of a series of squares and rectangles, separated by bunds approximately 10 cm in height, while terraced paddy fields consisted of long irregular shapes that followed natural contours of

5415-481: The East Atlantic and Mediterranean. The only true crayfish species native to the British Isles is the endangered white clawed crayfish . Fossil burrows very similar in construction to those of modern crayfish and likely produced by early crayfish are known from the Early Permian (~300-270 million years ago) of equatorial Pangea , in what is now North America ( Washington Formation ), and Europe ( Sardinia ). The oldest body fossils assigned to crayfish are known from

5510-406: The Middle Jeulmun pottery period (c. 3500–2000 BC) in the Korean Peninsula . Ancient paddy fields have been carefully unearthed in Korea by institutes such as Kyungnam University Museum (KUM) of Masan . They excavated paddy field features at the Geumcheon-ni Site near Miryang , South Gyeongsang Province . The paddy field feature was found next to a pit-house that is dated to the latter part of

5605-553: The Monsoon . The paddy cultivation plays a major role in socio-cultural life of rural India. Many regional festivals celebrate the harvest, such as Onam , Bihu , Thai Pongal , Makar Sankranti , and Nabanna . The Kaveri delta region of Thanjavur is historically known as the rice bowl of Tamil Nadu , and Kuttanadu is called the rice bowl of Kerala . Gangavathi is known as the rice bowl of Karnataka . Prime Javanese paddies yield roughly 6 metric tons of unmilled rice (2.5 metric tons of milled rice) per hectare . When irrigation

5700-485: The Nevėžis with the Šventoji was finished. It is 12 km in length. There is a pumping station near Kavarskas to supply the canal with water. Crayfish Crayfish are freshwater crustaceans belonging to the infraorder Astacidea , which also contains lobsters . Taxonomically, they are members of the superfamilies Astacoidea and Parastacoidea . They breathe through feather-like gills . Some species are found in brooks and streams, where fresh water

5795-402: The Yangtze cultures and their sizes increased, leading some archeologists to characterize them as true states , with clearly advanced socio-political structures. However, it is unknown if they had centralized control. In the terminal Neolithic (2500 to 2000 BC), Shijiahe shrank in size, and Liangzhu disappeared altogether. This is largely believed to be the result of the southward expansion of

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5890-461: The Yangtze was probably the site of the earliest rice cultivation. In 1998, Crawford & Shen reported that the earliest of 14 AMS or radiocarbon dates on rice from at least nine Early to Middle Neolithic sites is no older than 7000 BC, that rice from the Hemudu and Luojiajiao sites indicates that rice domestication likely began before 5000 BC, but that most sites in China from which rice remains have been recovered are younger than 5000 BC. During

5985-425: The Yangtze, but by 1250, 75% of China's population lived south of it. Such large-scale internal migration was possible due to introduction of quick-ripening strains of rice from Vietnam suitable for multi-cropping. Famous rice paddies in China include the Longsheng Rice Terraces and the fields of Yuanyang County, Yunnan . India has the largest paddy output in the world and is also the largest exporter of rice in

6080-426: The ability to filter and process mud. In aquaculture ponds using isotope analysis they were shown to build body tissue selectively from the animal protein portion of pelleted food and not the other components of the pellet. They have the potential to eat most foods, even nutrient poor material such as grass, leaves, and paper, but can be highly selective and need variety to balance their diet. The personalities of

6175-469: The archaeological site of Matsutaka in Mie Prefecture that dates to the late 2nd century. Ta ( 田 ) is used as a part of many place names as well as in many family names. Most of these places are somehow related to the paddy field and, in many cases, are based on the history of a particular location. For example, where a river runs through a village, the place east of the river may be called Higashida ( 東田 ), literally "east paddy field." A place with

6270-411: The area along and the delta of the Kaladan River , and the Central plains around Mandalay , though there has been an increase in rice farming in Shan State and Kachin State in recent years. Up until the later 1960s, Myanmar was the main exporter of rice. Termed the rice basket of Southeast Asia, much of the rice grown in Myanmar does not rely on fertilizers and pesticides, thus, although "organic" in

6365-411: The diet of these creatures was considered too complex since the first book ever written in the field of zoology, The Crayfish by T.H. Huxley (1879), where they were described as " detritivores ". This is why most researchers have not attempted to understand the diet of freshwater crayfish. The most complex study which matched the structure and function of the whole digestive track with ingested material

6460-589: The early Sino-Tibetan Longshan culture . Fortifications like walls (as well as extensive moats in Liangzhu cities) are common features in settlements during this period, indicating widespread conflict. This period also coincides with the southward movement of rice-farming cultures to the Lingnan and Fujian regions, as well as the southward migrations of the Austronesian, Kra-Dai, and Austroasiatic -speaking peoples to Mainland Southeast Asia and Island Southeast Asia . The spread of japonica rice cultivation and paddy field agriculture to Southeast Asia started with

6555-476: The eastern coast of Brazil , the Artibonite Valley in Haiti , Sacramento Valley in California , and West Lothian in Scotland among other places. Paddy cultivation should not be confused with cultivation of deepwater rice , which is grown in flooded conditions with water more than 50 cm (20 in) deep for at least a month. Global paddies' emissions account for at least 10% of global methane emissions . Drip irrigation systems have been proposed as

6650-505: The elimination of native species. Transporting crayfish as live bait has also contributed to the spread of zebra mussels in various waterways throughout Europe and North America, as they are known to attach themselves to exoskeleton of crayfishes. Crayfish are kept as pets in freshwater aquariums. They prefer foods like shrimp pellets or various vegetables, but will also eat tropical fish food, regular fish food, algae wafers, and small fish that can be captured with their claws. A report by

6745-471: The ensuing Warring States period (403–221 BC), culminating in the enormous Du Jiang Yan Irrigation System engineered by Li Bing by 256 BC for the State of Qin in ancient Sichuan . During the Eastern Jin (317–420) and the Northern and Southern Dynasties (420–589), land-use became more intensive and efficient, rice was grown twice a year and cattle began to be used for plowing and fertilization . By about 750, 75% of China's population lived north of

6840-613: The farmer to buy or grow rice seedlings. They are transplanted (usually by rice transplanter ) from the indoors into freshly flooded paddy fields in May. Farmers tend and weed their paddy fields through the summer until around the time of Chuseok , a traditional holiday held on 15 August of the Lunar Calendar (circa mid-September on the Solar Calendar). The harvest begins in October. Coordinating

6935-542: The finer material is usually eliminated from 16 to 26 hours after ingestion. All waste products coming out through the hindgut are wrapped in a peritrophic membrane , so they look like a tube. Such an investment in the wrapping of the microbial free faeces in a protein rich membrane is most likely the reason they are coprophagic. Such feeding behaviour based on selection, ingestion, and extreme processing ensures periodic feeding, as distinct from continuous grazing. They tend to eat to satiation and then take many hours to process

7030-422: The four genera of the family Astacidae live in western Eurasia and western North America , the 15 genera of the family Cambaridae live in eastern North America , and the single genus of Cambaroididae live in eastern Asia . The greatest diversity of crayfish species is found in southeastern North America, with over 330 species in 15 genera, all in the family Cambaridae. A further genus of astacid crayfish

7125-399: The harvest can be challenging because many Korean farmers have small paddy fields in a number of locations around their villages, and modern harvesting machines are sometimes shared between extended family members. Farmers usually dry the harvested grains in the sun before bringing them to market. The Hanja character for 'field', jeon ( Korean :  전 ; Hanja :  田 ),

7220-551: The individual crayfish can be a key determinant in the food preference behaviour in aquaria. Crayfish all over the world can be seen in an ecological role of benthic dwellers, so this is where most of their food is obtained - at the sediment/water interface in ponds, lakes, swamps, or burrows. When the gut contents are analysed, most of the contents is mud: fine particulate organic matter (FPOM) and mixed particles of lignin and cellulose (roots, leaves, bark, wood). Some animal material can also be identified, but this only contributes

7315-623: The land at various levels. Mumun Period rice farmers used all of the elements that are present in today's paddy fields, such as terracing, bunds, canals, and small reservoirs. We can grasp some paddy-field farming techniques of the Middle Mumun (c. 850–550 BC), from the well-preserved wooden tools excavated from archaeological rice fields at the Majeon-ni Site. However, iron tools for paddy-field farming were not introduced until sometime after 200 BC. The spatial scale of paddy-fields increased, with

7410-425: The material, leaving minimal chance of having more room to ingest other items. Crayfish usually have limited home range and so they rest, digest, and eliminate their waste, most commonly in the same location each day. Feeding exposes the crayfish to risk of predation, and so feeding behaviour is often rapid and synchronised with feeding processes that reduce such risks — eat, hide, process and eliminate. Knowledge of

7505-558: The migrations of the Austronesian Dapenkeng culture into Taiwan between 3500 and 2000 BC. The Nanguanli site in Taiwan, dated to ca. 2800 BC, has yielded numerous carbonized remains of both rice and millet in waterlogged conditions, indicating intensive wetland rice cultivation and dryland millet cultivation. From about 2000 to 1500 BC, the Austronesian expansion began, with settlers from Taiwan moving south to migrate to Luzon in

7600-461: The name Nevėžis could be derived from a Finnish word nevo meaning "swamp". The upper river has swampy banks. The name also relate by N phoneme to the rivers Neris and Nemunas that takes flow of the other two. The river gave name to many things including Panevėžys, the fifth largest city in Lithuania. Its name means "[Town] near Nevėžis." FK Nevėžis and KK Nevėžis are also named after

7695-419: The paddy field the most productive farming method. Paddy fields are represented by the kanji 田 (commonly read as ta or as den ) that has had a strong influence on Japanese culture. In fact, the character 田 , which originally meant 'field' in general, is used in Japan exclusively to refer to paddy fields. One of the oldest samples of writing in Japan is widely credited to the kanji 田 found on pottery at

7790-680: The pre-Austronesians and possibly also the Kra-Dai , and associated with the Kuahuqiao , Hemudu , Majiabang , Songze , Liangzhu , and Maquiao cultures . The second is in the middle Yangtze River, believed to be the homelands of the early Hmong-Mien speakers and associated with the Pengtoushan , Nanmuyuan , Liulinxi , Daxi , Qujialing , and Shijiahe cultures . Both of these regions were heavily populated and had regular trade contacts with each other, as well as with early Austroasiatic speakers to

7885-619: The production of rice. It was for that reason, that people usually built their houses next to paddy fields. The very spicy chili pepper that is often eaten in Malaysia, the bird's eye chili , is locally called cili padi , literally "paddy chili". Some research pertaining to Rainfed lowland rice in Sarawak has been reported. Rice is grown in Myanmar primarily in three areas – the Irrawaddy Delta ,

7980-718: The regular use of iron tools, in the Three Kingdoms of Korea Period (c. AD 300/400-668). The first paddy fields in Japan date to the Early Yayoi period (300 BC – 250 AD). The Early Yayoi has been re-dated, and based on studies of early Japanese paddy formations in Kyushu it appears that wet-field rice agriculture in Japan was directly adopted from the Lower Yangtze river basin in Eastern China. Although China's agricultural output

8075-437: The remaining 20–30% being Procambarus zonangulus (white river crawfish). Optimum dietary nutritional requirement of freshwater crayfish, or crayfish nutrient specifications are now available for aquaculture feed producers Like all crustaceans, crayfish are not kosher because they are aquatic animals that do not have both fins and scales . They are therefore not eaten by observant Jews . Crayfish are preyed upon by

8170-641: The rice bends with age". Most of the rice planting and harvesting is done by hand. The rice is then threshed and stored, ready for the mills. In Nepal, rice (Nepali: धान, Dhaan) is grown in the Terai and hilly regions. It is mainly grown during the summer monsoon in Nepal . Paddy fields are a common sight in the Philippines. Several vast paddy fields exist in the provinces of Ifugao , Nueva Ecija , Isabela , Cagayan , Bulacan , Quezon , and other provinces. Nueva Ecija

8265-675: The river. The Nevėžis is important in Lithuanian culture because it flows through the middle of Lithuania. During the Middle Ages, the river was considered to be a natural border between two regions of Lithuania : Samogitia and Aukštaitija . Nevėžis has about seventy tributaries. The largest are: In 1992, the Krekenava Regional Park was established in order to preserve the Middle Nevėžis ecosystem and natural surroundings. The park

8360-423: The run-off of fertilizers from agriculture, was becoming more and more overgrown with weeds. It was hoped that the introduction of grass carp would help to control the process. Critics argued that the fish would not survive in the relatively cold climate. However, local fishermen still catch carp introduced several years ago. The Nevėžis is connected with two other large rivers by canals. In order to reduce floods on

8455-434: The surface of leaves and sticks. Also crayfish have been shown to be coprophagic - eating their own faeces, they also eat their own exuviae ( moulted carapace ) and each other. They have even been observed leaving the water to graze. Detritus or mud is a mixture of dead plankton (plant and animal), organic wastes from the water column , and debris derived from the aquatic and terrestrial environments. Mostly detritus

8550-621: The west, and early Kra-Dai speakers to the south, facilitating the spread of rice cultivation throughout southern China. The earliest paddy field found dates to 4330 BC, based on carbon dating of grains of rice and soil organic matter found at the Chaodun site in Kunshan . At Caoxieshan, a site of the Neolithic Majiabang culture , archaeologists excavated paddy fields. Some archaeologists claim that Caoxieshan may date to 4000–3000 BC. There

8645-420: The world as of 2020. In India, West Bengal is the largest rice producing state. Paddy fields are a common sight throughout India, both in the northern Gangetic Plains and the southern peninsular plateaus. Paddy is cultivated at least twice a year in most parts of India, the two seasons being known as Rabi and Kharif respectively. The former cultivation is dependent on irrigation, while the latter depends on

8740-626: The world. In whole-ecosystem experiments simulating acid rain at the Experimental Lakes Area in Ontario, Canada , crayfish populations crashed – probably because their exoskeletons are weaker in acidified environments. In several countries, particularly in Europe, native species of crayfish are under threat by imported species, particularly the signal crayfish ( Pacifastacus leniusculus ). Crayfish are also considered an invasive predatory species, endangering native European species such as

8835-496: Was looking for ways to direct ships from the Neman directly to the port of Riga . The plan was abandoned because of insufficient funds. The idea was revisited again in 1914, the preparations for construction started but were interrupted by World War I . After reclaiming the origin of the Lėvuo, heavy rains would cause the flood of as many as twenty villages. It was decided to dig an 8 km length canal. In 1961–63 another canal connecting

8930-519: Was performed in the 1990s by Brett O'Brien on marron , the least aggressive of the larger freshwater crayfish with aquaculture potential, similar to redclaw and yabbies. Crayfish are closely related to lobsters , and together they belong to the infraorder Astacidea . Their phylogeny can be shown in the simplified cladogram below: Enoplometopidae Nephropidae Parastacidae Cambaroididae Astacidae Cambaridae Four extant (living) families of crayfish are described, three in

9025-470: Was spread in prehistoric times by the expansion of Austronesian peoples to Island Southeast Asia , Madagascar , Melanesia , Micronesia , and Polynesia . The technology was also acquired by other cultures in mainland Asia for rice farming, spreading to East Asia , Mainland Southeast Asia , and South Asia . Fields can be built into steep hillsides as terraces or adjacent to depressed or steeply sloped features such as rivers or marshes . They require

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