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Galaxias Eldoni
Eldon's galaxias (''Galaxias eldoni'') is an endangered galaxiid fish endemic to New Zealand. One of several fishes in the genus ''Galaxias'' found in Central Otago, it has a very small home range and is at risk of being driven to extinction by trout introduced for recreational fishing. Taxonomy Eldon's galaxias was described in 1997 by New Zealand freshwater ichthyologist Bob McDowall from specimens collected in 1995 and 1996. It is part of the '' Galaxias vulgaris'' species complex, and differs from '' Galaxias pullus'', another new species McDowall had found in the same area genetically and by its colour pattern: irregular stripes that continue across its back. The name recognises the ichthyologist G. A. (Tony) Eldon, who helped collect specimens and had retired not long before McDowall described this species. Description ''Galaxias eldoni'' is an elongated, deep-bodied ''Galaxias'', usually 80 mm in length (although very large individuals can reach 155 mm). Its s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bob McDowall
Robert (Bob) Montgomery McDowall (15 September 1939 – 20 February 2011) was one of New Zealand's most prominent freshwater ichthyologists. Biography McDowall was born on 15 September 1939, the son of dairy scientist Frederick Henry McDowall and entomologist Grace Edith Wall. He attended Palmerston North Boys' High School and went on to study for a BSc at Victoria University in 1958. Despite only receiving a C pass in Zoology, he was accepted into the graduate program where he completed an MSc thesis on the biology of the redfin bully. In 1963 he joined the Fisheries Division of the Marine Department of the Department of Scientific and Industrial Research. At that time, the main laboratories of the Marine Department were housed on the ground floor of the old Wellington City morgue - which McDowall described as an "unhappy and "exceedingly primitive' place with inadequate power and heating. McDowall's dissatisfaction at the Fisheries Division reached Barry Fell, formerly a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tokomairaro River
The Tokomairaro River is located in Otago, New Zealand. It flows southeast for some 50 kilometres (30 mi), reaching the Pacific Ocean at Toko Mouth 50 kilometres (30 mi) south of Dunedin. The town of Milton is located on the Tokomairaro's floodplain, close to the junction of its two main branches (which run past the north and south ends of the town). The name of the river is Māori Māori or Maori can refer to: Relating to the Māori people * Māori people of New Zealand, or members of that group * Māori language, the language of the Māori people of New Zealand * Māori culture * Cook Islanders, the Māori people of the C ..., and translates roughly as 'place where canoe must be poled' (a possible reference to the method needed to travel through the extensive wetlands, instead of the usual paddling). The Tokomairaro River is prone to seasonal flooding during the heavy rainfall months, August to October. Local industrial buildings have been forced to build high co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eldon's Galaxias (Galaxias Eldoni) Electrofishing
Eldon's galaxias (''Galaxias eldoni'') is an endangered galaxiid fish endemic to New Zealand. One of several fishes in the genus ''Galaxias'' found in Central Otago, it has a very small home range and is at risk of being driven to extinction by trout introduced for recreational fishing. Taxonomy Eldon's galaxias was described in 1997 by New Zealand freshwater ichthyologist Bob McDowall from specimens collected in 1995 and 1996. It is part of the '' Galaxias vulgaris'' species complex, and differs from '' Galaxias pullus'', another new species McDowall had found in the same area genetically and by its colour pattern: irregular stripes that continue across its back. The name recognises the ichthyologist G. A. (Tony) Eldon, who helped collect specimens and had retired not long before McDowall described this species. Description ''Galaxias eldoni'' is an elongated, deep-bodied ''Galaxias'', usually 80 mm in length (although very large individuals can reach 155 mm). Its s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Riffle
A riffle is a shallow landform in a flowing channel. Colloquially, it is a shallow place in a river where water flows quickly past rocks. However, in geology a riffle has specific characteristics. Topographic, sedimentary and hydraulic indicators Riffles are almost always found to have a very low discharge compared to the flow that fills the channel (approximately 10–20%), and as a result the water moving over a riffle appears shallow and fast, with a wavy, disturbed water surface. The water's surface over a riffle at low flow also has a much steeper slope than that over other in-channel landforms. Channel sections with a mean water surface slope of roughly 0.1 to 0.5% exhibit riffles, though they can occur in steeper or gentler sloping channels with coarser or finer bed materials, respectively. Except in the period after a flood (when fresh material is deposited on a riffle), the sediment on the riverbed in a riffle is usually much coarser than on that in any other in-chann ... [...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] |
Whitebait
Whitebait is a collective term for the immature fry of fish, typically between long. Such young fish often travel together in schools along coasts, and move into estuaries and sometimes up rivers where they can be easily caught using fine-meshed fishing nets. Whitebaiting is the activity of catching whitebait. Individual whitebait are tender and edible, and are considered a delicacy in New Zealand. The entire fish is eaten - including head, fins, bones, and bowels. Some species make better eating than others, and the particular species that are marketed as "whitebait" vary in different parts of the world. As whitebait consists of immature fry of many important food species (such as herring, sprat, sardines, mackerel, bass and many others) it is not an ecologically viable foodstuff and several countries impose strict controls on harvesting. Whitebait by region Alboran Sea The Alboran Sea is the westernmost element of the Mediterranean Sea. Whitebait have been consumed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paranephrops
''Paranephrops'' is a genus of freshwater crayfish found only in New Zealand. They are known by the English common names freshwater crayfish and koura, the latter from their Māori name of ''kōura''. The two species are the northern koura, ''Paranephrops planifrons'', found mainly in the North Island, but also in Marlborough, Nelson, and the West Coast of the South Island, and the southern koura, ''Paranephrops zealandicus'', found only in the eastern and southern of the South Island and on Stewart Island/Rakiura. Both species are a traditional food for Māori, and a small koura aquaculture industry supplies the restaurant market. Description The northern koura (''P. planifrons'') reaches lengths of about , whereas the southern koura (''P. zealandicus'') is slightly larger – – with relatively shorter antennae. Their first pair of legs ( chelipeds) are pincers used for scavenging food and warding off predators or other koura. The chelipeds in ''P. zealandicus'' are much hairi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mayfly
Mayflies (also known as shadflies or fishflies in Canada and the upper Midwestern United States, as Canadian soldiers in the American Great Lakes region, and as up-winged flies in the United Kingdom) are aquatic insects belonging to the order Ephemeroptera. This order is part of an ancient group of insects termed the Palaeoptera, which also contains dragonflies and damselflies. Over 3,000 species of mayfly are known worldwide, grouped into over 400 genera in 42 families. Mayflies have ancestral traits that were probably present in the first flying insects, such as long tails and wings that do not fold flat over the abdomen. Their immature stages are aquatic fresh water forms (called "naiads" or "nymphs"), whose presence indicates a clean, unpolluted and highly oxygenated aquatic environment. They are unique among insect orders in having a fully winged terrestrial preadult stage, the subimago, which moults into a sexually mature adult, the imago. Mayflies "hatch" (emerge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plecoptera
Plecoptera is an order of insects, commonly known as stoneflies. Some 3,500 species are described worldwide, with new species still being discovered. Stoneflies are found worldwide, except Antarctica. Stoneflies are believed to be one of the most primitive groups of Neoptera, with close relatives identified from the Carboniferous and Lower Permian geological periods, while true stoneflies are known from fossils only a bit younger. Their modern diversity, however, apparently is of Mesozoic origin. Plecoptera are found in both the Southern and Northern Hemispheres, and the populations are quite distinct, although the evolutionary evidence suggests species may have crossed the equator on a number of occasions before once again becoming geographically isolated. All species of Plecoptera are intolerant of water pollution, and their presence in a stream or still water is usually an indicator of good or excellent water quality. Description and ecology Stoneflies have a generaliz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brook Trout
The brook trout (''Salvelinus fontinalis'') is a species of freshwater fish in the char genus ''Salvelinus'' of the salmon family Salmonidae. It is native to Eastern North America in the United States and Canada, but has been introduced elsewhere in North America, as well as to Iceland, Europe, and Asia. In parts of its range, it is also known as the eastern brook trout, speckled trout, brook charr, squaretail, brookie or mud trout, among others. A potamodromous population in Lake Superior, as well as an anadromous population in Maine, is known as coaster trout or, simply, as coasters. The brook trout is the state fish of nine U.S. states: Michigan, New Hampshire, New Jersey, New York, North Carolina, Pennsylvania, Vermont, Virginia, and West Virginia, and the Provincial Fish of Nova Scotia in Canada. Systematics and taxonomy The brook trout was first scientifically described as ''Salmo fontinalis'' by the naturalist Samuel Latham Mitchill in 1814. The specific epithet "''fontina ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rainbow Trout
The rainbow trout (''Oncorhynchus mykiss'') is a species of trout native to cold-water tributaries of the Pacific Ocean in Asia and North America. The steelhead (sometimes called "steelhead trout") is an anadromous (sea-run) form of the coastal rainbow trout or Columbia River redband trout that usually returns to freshwater to spawn after living two to three years in the ocean. Freshwater forms that have been introduced into the Great Lakes and migrate into tributaries to spawn are also called steelhead. Adult freshwater stream rainbow trout average between , while lake-dwelling and anadromous forms may reach . Coloration varies widely based on subspecies, forms, and habitat. Adult fish are distinguished by a broad reddish stripe along the lateral line, from gills to the tail, which is most vivid in breeding males. Wild-caught and hatchery-reared forms of the species have been transplanted and introduced for food or sport in at least 45 countries and every continent except ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brown Trout
The brown trout (''Salmo trutta'') is a European species of salmonid fish that has been widely introduced into suitable environments globally. It includes purely freshwater populations, referred to as the riverine ecotype, ''Salmo trutta'' morpha ''fario'', a lacustrine ecotype, ''S. trutta'' morpha ''lacustris'', also called the lake trout, and anadromous forms known as the sea trout, ''S. trutta'' morpha ''trutta''. The latter migrates to the oceans for much of its life and returns to fresh water only to spawn. Sea trout in Ireland and Britain have many regional names: sewin in Wales, finnock in Scotland, peal in the West Country, mort in North West England, and white trout in Ireland. The lacustrine morph of brown trout is most usually potamodromous, migrating from lakes into rivers or streams to spawn, although evidence indicates some stocks spawn on wind-swept shorelines of lakes. ''S. trutta'' morpha ''fario'' forms stream-resident populations, typically in alpine stre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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