639 research outputs found

    The History, Present Condition, and Future of the Molluscan Fisheries of North and Central American and Europe: Volume 1, Atlantic and Gulf Coasts

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    This three-volume monograph represents the first major attempt in over a century to provide, on regional bases, broad surveys of the history, present condition, and future of the important shellfisheries of North and Central America and Europe. It was about 100 years ago that Ernest Ingersoll wrote extensively about several molluscan fisheries of North America (1881, 1887) and about 100 years ago that Bashford Dean wrote comprehensively about methods of oyster culture in Europe (1893). Since those were published, several reports, books, and pamphlets have been written about the biology and management of individual species or groups ofclosely related mollusk species (Galtsoff, 1964; Korringa, 1976 a, b, c; Lutz, 1980; Manzi and Castagna, 1989; Shumway, 1991). However, nothing has been written during the past century that is comparable to the approach used by Ingersoll in describing the molluscan fisheries as they existed in his day in North America or, for that matter, in Europe. (PDF file contains 224 pages.

    The Crustacean and Molluscan Fisheries of Honduras

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    Honduras has many communities of artisanal fishermen who land various species of crustaceans and mollusks, using hands, nets, traps, and free diving from shore and from dugout canoes. It also has industrial fisheries for spiny lobster, Panulirus argus; queen conch, Strombus gigas; and mainly pink shrimp, Penaeus notialis, using traps, scuba divers, and trawl nets

    Molluscan Fisheries of India

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    Molluscs form valuable fisheries in various parts of the coasts of India providing shellfish as food and as source of lime, pearls and decorative shells, as constituents of medicinal preparations etc. The present status of exploitation of molluscan resources in the country and the progress made in researches on the culture of bivalve molluscs are presented and the possibilities for better utilization of the resources by proper exploitation are emphasized. Molluscan resources exist at innumerable places along the coasts of India and are exploited in varying degree of intensity forming valuable fisheries. The fisheries and biological aspects of the major species of molluscs of economic importance have been studied only at a few areas in the last few years. Exploitation of the available molluscan resources it is possible for India to increase production substantially from the present level which will provide greater quantities of wholesome sea-food to meet internal demand and requirements of export industry

    The History, Present Condition, and Future of the Molluscan Fisheries of North and Central America and Europe: Volume 2, Pacific Coast and Supplemental Topics

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    Over 100 molluscan species are landed in Mexico. About 30% are harvested on the Pacific coast and 70% on the Atlantic coast. Clams, scallops, and squid predominate on the Pacific coast (abalone, limpets, and mussels are landed there exclusively). Conchs and oysters predominate on the Atlantic coast. In 1988, some 95,000 metric tons (t) of mollusks were landed, with a value of $33 million. Mollusks were used extensively in prehispanic Mexico as food, tools, and jewelry. Their use as food and jewelry continues. Except in the States of Baja California and Baja California Sur, where abalone, clams, and scallops provide fishermen with year-round employment, mollusk fishing is done part time. On both the Pacific and Atlantic coasts, many fishermen are nomads, harvesting mollusks wherever they find abundant stocks. Upon finding such beds, they build camps, begin harvesting, and continue until the mollusks become so scarce that it no longer pays to continue. They then look for productive beds in other areas and rebuild their camps. Fishermen harvest abalones, mussels, scallops, and clams by free-diving and using scuba and hooka. Landings of clams and cockles have been growing, and 22,000 t were landed in 1988. Fishermen harvest intertidal clams by hand at wading depths, finding them with their feet. In waters up to 5 m, they harvest them by free-diving. In deeper water, they use scuba and hooka. Many species of gastropods have commercial importance on both coasts. All species with a large detachable muscle are sold as scallops. On the Pacific coast, hatchery culture of oysters prevails. Oyster culture in Atlantic coast lagoons began in the 1950's, when beds were enhanced by spreading shells as cultch for spat. (PDF file contains 228 pages.

    Implications of historic development and economic performance of molluscan fisheries in China 1950-2017

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    1667-1679This is the first attempt that discusses molluscan fisheries of China in terms of economic perspective. The originality of this research stems into the analysis of a long series of data, 1950-2017, 68 years covering pre and post-reform era, starting from the time when China had limited infrastructure to becoming world’s largest producer of aquatic products. Since its liberation, the Chinese economy has gone through various disruptions and transformations, which include famine, Cultural Revolution and accession to world trade organization during the late 1950s, the late 1960s and in 2011 correspondingly. Coupled with various macroeconomic perturbations, Chinese fisheries sector has also gone through various transformations of its own such as the shift from inshore to offshore fishing with the passage of time. Consequently, molluscan fisheries sector has experienced remarkable changes. Molluscan fisheries landings have considerably increased from 1950 (90500 t) to 2017 (1797475 t). However, the decline in the capture production has been observed after 2000 due to overexploitation. Trade (export + import) of molluscs (volume + value) is on the move since 1984 as a result of market liberalization and development policies. The tendency for molluscs consumption is also increasing with the passage of time

    The molluscan fisheries of Germany

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    The German molluscan fishery has always concentrated on the North Sea. Mollusks occur in the Baltic Sea, but are not as marketable. In prehistory and the Middle Ages, coastal inhabitants gathered mussels, Mytilus edulis, cockles, Cerastoderma edule, and flat oysters, Ostrea edulis, for food and also used mussels as agricultural fertilizer. An organized oyster fishery developed in the 16th century and had considerable economic importance for 300 years. Oysters were dredged with sailing vessels near the coast, as well as far offshore. Catches peaked in the second half of the l 9th century at 3-5 million oysters per year. They declined dramatically in the following decades due to permanent recruitment failures, and the flat oyster finally disappeared from the German coast in the l 950's. An organized fishery for freshwater pearl mussels, Margaritifera margaritifera, also developed at the end of the Middle Ages, but mismanagement and environmental degradation since the late 19th century have brought this species to the brink of extinction as well. Other mollusks harvested on a smaller scale in the past have been softshell clams, Mya arenaria, and whelks, Buccinum undatum. The modern mussel fishery for human food began in 1929 with the introduction of novel dredging methods. Annual catches were in the order of a few thousand tons during the first half of this century and have attained 20,000-60,000 tons since the early l980's; concomitantly, prices have increased five-fold in recent decades. The fishery is now based on 14 highly specialized vessels harvesting from 3,800 ha (9,500 acres) of culture plots which are seeded with mussels from natural beds. Pacific oysters, Crassostrea gigas, were first introduced in the l970's, and a natural population has recently begun to establish itself. They are cultured by one company which imports half-grown seed from the British Isles. A nearshore hydraulic dredge fishery for cockles began in 1973, but was banned for political reasons in 1992. It was replaced by a new offshore fishery for hard clams, Spisula solida, which ended when the clam stock suffered total mortality in the 1995-96 ice winter. The molluscan fisheries and aquaculture sector (production and processing) in 1995 employed almost 100 people year-round and another 50-100 seasonally. The annual product is about US$35 million

    The Fisheries for Mangrove Cockles,Anadaraspp., from Mexico to Peru, With Descriptions of Their Habitats and Biology, the Fishermen’s Lives, and the Effects of Shrimp Farming

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    This paper provides the first description of the mangrove cockle, Anadara spp., fisheries throughout their Latin American range along the Pacific coast from Mexico to Peru. Two species, A. tuberculosa and A. grandis, are found over the entire range, while A. similis occurs from El Salvador to Peru. Anadara tuberculosa is by far the most abundant, while A. grandis has declined in abundance during recent decades. Anadara tuberculosa and A. similis occur in level mud sediments in mangrove swamps, comprised mostly of Rhizophora mangle, which line the main-lands and islands of lagoons, whereas A. grandis inhabits intertidal mud flats along the edges of the same mangrove swamps. All harvested cockles are sexually mature. Gametogenesis of the three species occurs year round, and juvenile cockles grow rap-idly. Cockle densities at sizes at least 16–42 mm long ranged from 7 to 24/m2 in Mexico. Macrofaunal associates of cockles include crustaceans, gastropods, and finfishes. The mangrove swamps are in nearly pristine condition in every country except Honduras, Ecuador, and Peru, where shrimp farms constructed in the 1980’s and 1990’s have destroyed some mangrove zones. In addition, Hurricane Mitch destroyed some Honduran mangrove swamps in 1998. About 15,000 fishermen, including men, women, and children, harvest the cockles. Ecuador has the largest tabulated number of fishermen, 5,055, while Peru has the fewest, 75. Colombia has a large number, perhaps exceeding that in Ecuador, but a detailed census of them has never been made. The fishermen are poor and live a meager existence; they do not earn sufficient money to purchase adequate food to allow their full health and growth potential. They travel almost daily from their villages to the harvesting areas in wooden canoes and fiberglass boats at low tide when they can walk into the mangrove swamps to harvest cockles for about 4 h. Harvest rates, which vary among countries owing to differences in cockle abundances, range from about 50 cockles/fisherman/day in El Salvador and Honduras to 500–1,000/ fisherman/day in Mexico. The fishermen return to their villages and sell the cockles to dealers, who sell them mainly whole to market outlets within their countries, but there is some exporting to adjacent countries. An important food in most countries, the cockles are eaten in seviche, raw on the half-shell, and cooked with rice. The cockles are under heavy harvesting pressure, except in Mexico, but stocks are not yet being depleted because they are harvested at sizes which have already spawned. Also some spawning stocks lie within dense mangrove stands which the fishermen cannot reach. Consumers fortunately desire the largest cockles, spurning the smallest. Cockles are important to the people, and efforts to reduce the harvests to prevent overfishing would lead to severe economic suffering in the fishing communities. Pro-grams to conserve and improve cockle habitats may be the most judicious actions to take. Preserving the mangrove swamps intact, increasing their sizes where possible, and controlling cockle predators would lead to an increase in cockle abundance and harvests. Fishes that prey on juvenile cockles might be seined along the edges of swamps before the tide rises and they swim into the swamps to feed. Transplanting mangrove seedlings to suitable areas might increase the size of those habitats. The numbers of fishermen may increase in the future, because most adults now have several children. If new fishermen are tempted to harvest small, immature cockles and stocks are not increased, minimum size rules for harvestable cockles could be implemented and enforced to ensure adequate spawning

    Status of Molluscan Fisheries of India

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    Status of Molluscan Fisheries of Indi

    The History and Literature of America's Oysters

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    Historically, America's use and enjoyment of the oyster extend far back into prehistoric times. The Native Americans often utilized oysters, more intensively in some areas than in others, and, at least in some areas of the Caribbean and Pacific coast, the invading Spanish sought oysters as eagerly as they did gold-but for the pearls. That was the pearl oyster, Pinctada sp., and signs of its local overexploitation were recorded early in the 16th century. During the 1800's, use of the eastern oyster grew phenomenally and, for a time, it outranked beef as a source of protein in some parts of the nation. Social events grew up around it, as it became an important aspect of culture and myth. Eventually, research on the oyster began to blossom, and scientific literature on the various species likewise bloomed-to the extent that when the late Paul Galtsoff wrote his classic treatise "The American oyster Crassostrea virginica Gmelin" in 1954, he reported compiling an extensive bibliography of over 6,000 subject and author cards on oysters and related subjects which he deposited in the library of the Woods Hole Laboratory of the Bureau of Commercial Fisheries (now NMFS). That large report, volume 64 (480 pages) of the agency's Fishery Bulletin, was a bargain at $2.75, and it has been a standard reference ever since. But the research and the attendant literature have grown greatly since Galtsoff's work was published, and now that has been thoroughly updated
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