Seine(redirected from seine nets)
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Seine(sān, Fr. sĕn), Lat. Sequana, river, c.480 mi (770 km) long, rising in the Langres Plateau and flowing generally NW through N France. It passes Troyes, Melun, and Paris, whence it meanders in large loops through Normandy, past Rouen, and empties into the English Channel in an estuary between Le Havre and Honfleur. With its tributaries (the Aube, Marne, Oise, Yonne, Loing, and Eure) and connecting canals, it drains the entire Paris basin. One of the most navigable rivers in France, it has been a great commercial artery since Roman times. The channel of the Seine is dredged and oceangoing vessels can dock at Rouen. Much of France's internal and foreign trade moves on the Seine. Paris, Rouen, and Le Havre owe their prosperity to their favorable location on the river.
a net for catching fish; it consists of net canvas and ropes. To increase the strength of the net canvas, it is bound around the edges with a single or double thread, and sometimes it is sewn with a strip of even stronger net. Its outer edges are secured to ropes called head and bottom lines; thin strengthening ropes called up-and-down lines pass up, down, and across the net. To keep the seine afloat, the head lines are equipped with floats. The bottom lines are weighted to make them sink.
In seining, part of the body of water is surrounded by the fishing device, which is then pulled from the water onto the shore or a ship, together with the fish it contains. Thus, the seine is an active device—that is, the catch is made mainly through the motion of the device itself. For this reason, all types of seines have drawstrings, called shore lines, attached to the wings of the net. In seine fishing the fish must move along the wings and be confined within a special section called a bunt; they must not become stuck in the mesh or become tangled in the net canvas. To avoid this, the net canvas is made from thick thread. The fish are loaded manually or mechanically from the bunt (for example, with a fish pump).
Seine nets may be of the beach or drag type; the former are used in ocean, river, and lake fishing, and the latter are used in ocean fishing.
A beach seine consists of a bunt, two leads, two wings, and two shore lines. It is thrown into the water and then dragged back onto the shore. Such seines may be of the equal-winged or unequal-winged types. The length of equal-winged nets is 100–1,000 m, with a depth at the center of 2–20 m. Unequal-winged nets are among the largest fishing devices: they are 1,000–3,000 m long and 10–30 m deep.
Drag seines are divided into pelagic types (for fishing in deep water) and bottom types (the latter are thrown into the water from a ship and lifted on board). Pelagic seines are of the purse, two-boat, and ring types. A purse seine is a deep, rectangular net up to 1,500 m long and up to 200 m deep, which surrounds the school of fish. The head line is equipped with floats, and the bottom line is weighted. The bottom line has metal rings attached to it by leads; a line is passed through the rings and gathers the lower edge of the seine so that the fish cannot swim under it. Purse seines may be single-winged and double-winged; the former are most important commercially.
Both types of seines may have walls of equal or unequal depth. The bunt of such a seine is made in the shape of a rectangular section sewn from thicker net canvas. Purse seines are usually used in situations in which the bottom line does not reach the bottom of the water; they are highly efficient and are widely used.
Two-boat seines are structurally similar to beach seines (the most widely used are equal-winged edged nets) and are used for shallow-water fishing. The ring seine is intermediate between two-boat and purse types of net. It has a sacklike bunt (in contrast to the purse seine) and gathering rings along the bottom line (in contrast to the two-boat seine). The ring seine is an equal-winged net consisting of a bunt, two leads, two wings, and two shore lines, whose length is ten times greater than the length of the net portion along the head lines. The length of the ring seine along the head lines is 20–70 m, the depth at the center is 2–8 m, and the shore lines are 2,000–3,000 m long.
V. A. IONAS
until 1964, a department in France, which included Paris and the closest suburbs. In connection with the administrative reorganization of the region of Paris (now the Region Ile de France), the departments Paris, Seine-Saint-Denis, Hautsde-Seine, and Val-de-Marne were formed from the department of Seine.
a river in France. The Seine is 776 km long and drains an area of 78,600 sq km. It originates in the southern part of the Plateau de Langres and flows primarily in the Paris Basin in a broad valley; the channel is meandering, especially below Paris, through which the Seine flows for a distance of approximately 50 km. Near Le Havre, the Seine empties into the Bay of the Seine in the English Channel. The bay forms a funnel-shaped estuary, with a length of more than 25 km and a width of 2–10 km. The principal tributaries of the Seine are the Aube, Marne, and Oise, on the right, and the Yonne, on the left. The Seine is fed primarily by rain. Its level rises between November and March; in the summer there is a brief low-water period. The mean flow rate at Paris is approximately 250 cu m per sec, while near the mouth it is 450–500 cu m per sec. The influence of tides extends 35 km above Rouen, with ranges of 2 m at Rouen and 7.5 m at Le Havre. During periods of strong freshets, there is flooding, although hydraulic-engineering projects on the Seine and its tributaries have reduced the danger of flooding to Paris.
The Seine is France’s most important waterway and is navigable, by way of a lateral canal, from the city of Troyes; below the confluence of the Aube and the Seine, navigation is conducted on the Seine itself. Because of high tides, ships enter the mouth of the Seine through the bypass Tancarville Canal. Sea vessels with drafts of up to 6.5 m can travel as far as Rouen, river vessels with drafts of up to 3.2 m travel between Rouen and Paris, and vessels with drafts of up to 1.3 m can travel farther upstream. The Seine is linked by an extensive network of canals with the Somme, Scheldt, Meuse, Rhine, Saône, Loire, and other rivers. The Seine’s principal ports are Paris, Rouen, and Le Havre.
A. P. MURANOV