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38-503: The name is first recorded in the Neptune francois of 1693 as Le Passage de l'Yroise ( passage = " channel "); as Passage de l'Iroise in the 18th century; as Iroise in the 19th century; and as mer d'Iroise ( mer = "sea") in the 1970s, by the seabed exploration industry. The name appears to have been fixed not by local seafarers but rather by staff at the naval base at Brest . The 18th-century maps identify "Passage de l'Iroise" as

76-579: A channel is a landform on which a relatively narrow body of water is situated, such as a river , river delta or strait . While channel typically refers to a natural formation, the cognate term canal denotes a similar artificial structure. Channels are important for the functionality of ports and other bodies of water used for navigability for shipping . Naturally, channels will change their depth and capacity due to erosion and deposition processes. Humans maintain navigable channels by dredging and other engineering processes. By extension,

114-483: A constant flux. Channel heads associated with hollows in steep terrain frequently migrate up and down hillslopes depending on sediment supply and precipitation. Natural channels are formed by fluvial process and are found across the Earth . These are mostly formed by flowing water from the hydrological cycle , though can also be formed by other fluids such as flowing lava can form lava channels . Channels also describe

152-506: A scientific advisory (June 2013), it is stressed that fishing mortality is increasing. The total biomass has been declining since 2005. Total biomass assumed as the best stock size indicator in the last two years (2011–2012) was 32% lower than the total biomass in the three previous years (2008–2010). European seabass was one of Europe's first fish to be farmed commercially. Historically, they were cultured in coastal lagoons and tidal reservoirs before mass-production techniques were developed in

190-546: A year or two. Annual catches of wild European seabass are relatively modest, fluctuating between 8,500 and 11,900 tonnes from 2000 to 2009. Most reported catches originate from the Atlantic Ocean, with France typically reporting the highest catches. In the Mediterranean, Italy used to report the largest catches but has been surpassed by Egypt. The fish has come under increasing pressure from commercial fishing and became

228-420: Is a difference between low gradient streams (less than a couple of percent in gradient or slightly sloped) and high gradient streams (steeply sloped). A wide variety of stream channel types can be distinguished (e.g. braided rivers , wandering rivers, single-thread sinuous rivers etc.). During floods , water flow may exceed the capacity of the channel and flood waters will spill out of the channel and across

266-522: Is also increasingly popular, particularly in view of the many accessible wrecks and spectacular underwater vistas. Owing to the hazardous conditions at sea, the high density of shipping and a number of shipwrecks in recent years, the French authorities have introduced special search and rescue operations. These rely on vessels such as the Abeille Bourbon , as well as a number of large lifeboats based in

304-645: Is also recognized as the richest environment for seaweed in Europe, with some 300 species. As a result, on 2 October 2007, the French authorities designated this area as the country's first marine park, officially labelled Parc naturel marin d'Iroise. Its three main objectives are to increase knowledge of the marine environment, to protect the area's habitats and species, and to develop marine activities of all kinds. The Iroise Marine Park covers an area of 3,550 km (1,370 sq mi) from latitude 48°31′N (the north coast of Ushant ) and latitude 47°59′N (south coast of

342-660: Is found in a large part of the eastern Atlantic Ocean , from southern Norway to Senegal . It can also be found in the entire Mediterranean Sea and in the southern Black Sea but is absent from the Baltic Sea . It has entered the Red Sea through the Suez Canal as an anti-Lessepsian migrant . It is a seasonally migratory species, moving further winter spawning grounds during at least one month before moving towards their summer feeding areas. The European seabass hunts as much during

380-503: Is found in the northeast Atlantic Ocean , and the second is in the western Mediterranean Sea. The two populations are separated by a relatively narrow distance in a region known as the Almeria-Oran oceanographic front , located east of the Spanish city of Almería . The exact reason for this separation is unknown, as the geographic divide should not account for the lack of gene flow between

418-456: Is frequently called a canal , with the Panama Canal providing an example. The term not only includes the deep-dredged   ship-navigable parts of an estuary or river leading to port facilities, but also to lesser channels accessing boat port-facilities such as marinas . When dredged channels traverse bay mud or sandy bottoms, repeated dredging is often necessary because of

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456-579: Is obscure; theories include: From the 1990s, "Iroise" became popular in Finistère in the name of many local businesses and associations. The Pont de l'Iroise bridge was opened in 1994. in maritime weather forecasts by Météo-France and Spain's AEMET , "Iroise" denotes the sea area east of a line from 48°27′N 6°0′W  /  48.450°N 6.000°W  / 48.450; -6.000 to 47°30′N 6°0′W  /  47.500°N 6.000°W  / 47.500; -6.000 ; this corresponds to

494-661: Is the most upslope part of a channel network and is defined by flowing water between defined identifiable banks. A channel head forms as overland flow and/or subsurface flow accumulate to a point where shear stress can overcome erosion resistance of the ground surface. Channel heads are often associated with colluvium , hollows and landslides . Overland flow is a primary factor in channel initiation where saturation overland flow deepens to increase shear stress and begin channel incision. Overland flows converge in topographical depressions where channel initiation begins. Soil composition, vegetation, precipitation, and topography dictate

532-540: The British Isles , it is known as the "European bass," "European seabass," "common bass," "capemouth," "king of the mullets," "sea bass," "sea dace," "sea perch," "white mullet," "white salmon," or simply "bass". M. mississippiensis [REDACTED] M. chrysops [REDACTED] M. americana [REDACTED] M. saxatillis [REDACTED] D. punctatus D. labrax There are two genetically distinct populations of wild European seabass. The first

570-510: The Crozon peninsula in the roadstead of Brest . Fishing, though less important than in the past, is still practised, especially through the ports of Le Conquet , Douarnenez , Camaret and Brest. Catches range from crabs to sardines and monkfish . The area is also popular for sailing and pleasure boating, particularly in the less exposed areas along the coast and in Douarnenez Bay . Diving

608-550: The Raz de Sein or the Goulet de Brest . Many lighthouses were erected in the area to guide sailors. Many local legends describe lost ships and tragedies at sea. The Iroise Sea enjoys a variety of activities. The French navy has been active there since 1631, when Brest was established as a naval base . Since the late 20th century, it has been a centre of submarine activity, owing to the nuclear submarine base established at Île Longue on

646-476: The branzino , European bass , sea bass , common bass , white bass , capemouth , white salmon , sea perch , white mullet , sea dace or loup de mer , is a primarily ocean-going fish native to the waters off Europe 's western and southern and Africa 's northern coasts, though it can also be found in shallow coastal waters and river mouths during the summer months and late autumn. It is one of only six species in its family , Moronidae , collectively called

684-581: The valley bottom, floodplain or drainage area . Examples of rivers that are trapped in their channels: Grand Canyon and Black Canyon of the Gunnison . In a larger nautical context, as a geographical place name, the term channel is another word for strait , which is defined as a relatively narrow body of water that connects two larger bodies of water. In this nautical context, the terms strait , channel , sound , and passage are synonymous and usually interchangeable. For example, in an archipelago ,

722-587: The Île de Sein ), the mainland coastline to the east except for the Rade de Brest, and the 12-nautical-mile (22 km) limit on French territorial waters to the west. The Iroise Sea is among the world's most important biogeographic transition zones. This is a dividing line between the temperate marine and the cold-temperate and boreal marine animals. 48°13′N 04°48′W  /  48.217°N 4.800°W  / 48.217; -4.800 Channel (geography) In physical geography and hydrology ,

760-545: The amount and rate of overland flow. The composition of a soil determines how quickly saturation occurs and cohesive strength retards the entrainment of material from overland flows. Vegetation slows infiltration rates during precipitation events and plant roots anchor soil on hillslopes. Subsurface flow destabilizes soil and resurfaces on hillslopes where channel heads are often formed. This often results in abrupt channel heads and landslides. Hollows form due to concentrated subsurface flows where concentrations of colluvium are in

798-401: The century and a half following, it was classified under a variety of new synonyms, with Dicentrarchus labrax winning out as the accepted name in 1987. Its generic name, Dicentrarchus , derives from Greek , from the presence of two anal spines, "di" meaning two, "kentron" meaning sting, and "archos" meaning anus. The European bass is sold under dozens of common names in various languages. In

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836-500: The channel leading north-west from Pointe Saint-Mathieu and keeping south of Ushant (Ouessant) and the Ponant Islands. From the 19th century, the term Iroise encompassed all the sea along the west coast of Brittany between Ouessant and Sein. While this remains the limit used by mariners, some twentieth-century sources have used mer d'Iroise to denote the entire Celtic Sea as far as Ireland and Great Britain. The meaning of Iroise

874-453: The day as it does at night, feeding on small fish (both pelagic, such as sardines , sprats , and sand smelts , and demersal, such as sand eels ), polychaetes , cephalopods (such as squid ), and crustaceans . The big fish weighing more than 4 kg (8.8 lb) are mostly night hunters. They spawn from February to June, mostly in inshore waters. As fry they are pelagic, but as they develop, they move into estuaries, where they stay for

912-554: The deeper course through a reef , sand bar , bay , or any shallow body of water. An example of a river running through a sand bar is the Columbia Bar —the mouth of the Columbia River . A stream channel is the physical confine of a stream ( river ) consisting of a bed and stream banks . Stream channels exist in a variety of geometries. Stream channel development is controlled by both water and sediment movement. There

950-457: The focus in the United Kingdom of a conservation effort by recreational anglers. The Republic of Ireland has strict laws regarding bass. All commercial fishing for the species is banned, and several restrictions are in place for recreational anglers: a closed season from May 15 – June 15 inclusive every year; a minimum size of 400 mm (16 in); and a bag limit of two fish per day. In

988-465: The late 1960s. It is the most important commercial fish widely cultured in the Mediterranean. Greece, Turkey, Italy, Spain, Croatia, and Egypt are the most important farming countries. Annual production was more than 120,000 tonnes in 2010. The world's biggest producer of European seabass is Turkey. Branzino, sometimes known as "spigola" in southern Italy, is popular in Italian cuisine as a main course. It

1026-420: The most common size is only about half of that at 0.5 m (1 ft 8 in). Individuals are silvery grey and sometimes a dark-bluish color on the back. Juveniles form schools and feed on invertebrates , while adults are less social and prefer to consume other fish. They are generally found in the littoral zone near the banks of rivers, lagoons, and estuaries during the summer and migrate offshore during

1064-691: The northern part of the UK shipping forecast sea area of Biscay . The Iroise coastline consists of a rich variety of beaches, rocky cliffs, sand dunes, coves and islands such as the Île de Sein and the Island of Molene . The considerable differences in depth and the adjacent English Channel create the strong currents through the Iroise. High tides in the Channel bring about strong north-easterly currents, which reverse at low tide. The currents can reach particularly high speeds at

1102-479: The ports of Douarnenez , Camaret , Le Conquet , Molène and Ushant . Despite several major oil spills and cases of overfishing , the Iroise Sea is still rich in flora and fauna. It is especially well known for its seabass , its shoals of dolphin , seals , lobsters and, on occasion, sunfish , basking shark and whales . The many varieties of seabird include cormorants , guillemots and herons . The sea

1140-400: The product of the sediment load and bed Bukhara size is proportional to the product of discharge and channel slope. A term " navigable channel " is used as a nautical term to mean a lane for ship travel, frequently marked (cf. Buoy ) and sometimes dredged . Thoresen distinguishes few categories of channels, from A (suitable for day and night navigation with guaranteed fairway depth ) all

1178-765: The temperate basses. It is fished and raised commercially and is considered the most important fish currently cultured in the Mediterranean . In Ireland and the United Kingdom, the popular restaurant fish sold and consumed as sea bass is exclusively the European bass. In North America, it is widely known by one of its Italian names, branzino . European seabass is a slow-growing species that takes several years to reach adulthood. An adult European seabass usually weighs around 2.5 kg (5.5 lb). European seabass can reach measurements of up to 1 m (3 ft 3 in) in length and 12 kg (26 lb) in weight, though

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1216-430: The term also applies to fluids other than water, e.g., lava channels . The term is also traditionally used to describe the waterless surface features on Venus . Channel initiation refers to the site on a mountain slope where water begins to flow between identifiable banks. This site is referred to as the channel head and it marks an important boundary between hillslope processes and fluvial processes. The channel head

1254-420: The two populations. The larval stage of the European seabass can last up to 3 months, during which it cannot swim well, and even a small amount of water flow should transport some individuals between the two regions. In addition, juveniles can survive temperature and salinity changes, and adults can migrate hundreds of miles. European seabass habitats include estuaries , lagoons , coastal waters, and rivers. It

1292-678: The unstable subsequent movement of benthic soils. Responsibility for monitoring navigability conditions of navigation channels to various port facilities varies, and the actual maintenance work is frequently performed by a third party. Storms, sea-states, flooding, and seasonal sedimentation adversely affect navigability . In the U.S., navigation channels are monitored and maintained by the United States Army Corps of Engineers (USACE), although dredging operations are often carried out by private contractors (under USACE supervision). USACE also monitors water quality and some remediation. This

1330-512: The water between islands is typically called a channel or passage . The English Channel is the strait between England and France. The channel form is described in terms of geometry (plan, cross-sections, profile) enclosed by the materials of its bed and banks. This form is under influence of two major forces: water discharge and sediment supply. For erodible channels the mutual dependence of its parameters may be qualitatively described by Lane's Principle (also known as Lane's relationship ):

1368-400: The way to D with no navigational aids and only estimated depths provided to the shipmaster . With regard to the dredging , channels can be unrestricted (wide enough to accommodate 10-15 widths of a largest ship used in this channel, semi-restricted with limited dredging in shallow waters, and fully restricted , where the entire channel is dredged. The latter, entirely human-made, channel

1406-474: The winter. European sea bass feed on prawns, crabs and small fish. Though it is a sought-after gamefish, it is listed as Least Concern by the International Union for Conservation of Nature because it is widespread and there are no known major threats. The European seabass was first described in 1758 by Swedish zoologist Carl Linnaeus in his work Systema Naturae . He named it Perca labrax . In

1444-1313: Was first established under the Rivers and Harbors Act of 1899 and modified under acts of 1913, 1935, and 1938. For example, the USACE developed the Intracoastal Waterway , and has the Mississippi Valley Division responsible for the Mississippi River from the Gulf to Cairo, Illinois , the North Atlantic Division for New York Harbor and Port of Boston , and the South Pacific Division for Port of Los Angeles and Port of Long Beach . Waterways policing as well as some emergency spill response falls under United States Coast Guard jurisdiction, including inland channels serving ports like Saint Louis hundreds of miles from any coast. The various state or local governments maintain lesser channels, for example former Erie Canal . European seabass The European seabass ( Dicentrarchus labrax ), also known as

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