Seaweeds are among the most valuable of the aquatic resources of the Japanese Empire, and conduce largely to the prominent rank attained by the fisheries of that country. While marine plants are extensively utilized in France, Ireland, Scotland, and other European countries, in the East Indies, in China, and elsewhere, in no other country are such products relatively and actually so important or utilized in such a large variety of ways as in Japan. The seaweed industries of Japan owe their importance to the great extent of the coast line (estijnated at 18,000 miles); to the abundance and variety of useful alga?; and to the ingenuity of the people in putting the different kinds of plants to the most appropriate uses and in utilizing them to the fullest extent. The value of the seaweeds prepared in Japan at the present time exceeds $2,000,000- annually, this sum excluding the value of very large quantities of marine plants which do not enter into commerce but are used locallj' in the families of the fishermen. In view of the extent and long continuance of these industries, some diminution in the supply of economic alga? might reasonably be looked for, and this has in fact occurred; but while excessive gathering has influenced the abundance of some species, much more serious decrease has been brought about by conditions not connected with the seaweed industries. Investigations conducted by the imperial fisheries bureau have indicated that the disappearance of useful algie on a number of sections of the coast has resulted from a temporary freshening of the littoral waters, probably owing to improper lumber operations near the headwaters of streams. The denuded areas have always been contiguous to the mouths of rivers or within the possible range of influence of streams during freshets. It is reported that in a few places certain algae have been able partly to reestablish themselves, but the process is very slow, and complete replenishment will require many years, even if no lowering of water density ensues in the meantime. Some experimental planting in the denuded districts has been undertaken with favorable results, but on a very small scale. In other parts of Japan cultivation is extensively carried on, but as yet is directed to practically only one species, the laver {Porjihyra ladniata). It is noteworthy that the disappearance of seaweeds has injuriously affected another fishery—namely, that for abalones, which rank among the important water products of Japan. These mollusks feed among the alga? and are no longer found on large areas of bottom on which they formerly abounded.
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The present paper deals with the Indian seaweeds of economic value and the potential resources available in the inshore waters of the country. Results of the sample surveys carried out to estimate the standing crops of all marine plants growing in the Palk Bay area are given. Possibilities of cultivating the commercially valuable species in sheltered and calm areas of the coastline are indicated based on the culture experiments conducted with Gracilaria lichenoides and G. corticata.
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Canada occupies a special place among the world producers of seaweeds, mostly because it ranked first, from approximately 1950 to 1970, as a producer of the red alga Chondrus crispus (Irish moss), historically the first source of raw material for carrageenan extraction. However, seaweed harvesting along the coasts of the Maritimes is not a long-standing tradition, except in the case of Palmaria palmata (dulse), which has been harvested along the Bay of Fundy (especially on Grand Manan Island) for more than a century (even if the start of this cottage industry is difficult to date precisely). This chapter will focus on the seaweed industry on the Atlantic (East) Coast of Canada, the Pacific (West) Coast industry being treated in a separate chapter by S. Lindstrom. Along the East Coast, the emphasis will be on the Maritimes, which include the provinces of Prince Edward Island (PEI), Nova Scotia (NS) and New Brunswick (NB) (Fig. 1). The two provinces of Québec, and Newfoundland and Labrador are omitted, even though they have been the subject of numerous surveys, exploratory missions and reports, because no significant industry is presently operating there, except the sporadic harvesting of Laminaria sp. (kelp) in Québec (along the St. Lawrence Estuary and the Baie des Chaleurs) which was estimated at 500 wet tons (WT) in 1994 (Bodiguel 1995), and the harvesting of Ascophyllum nodosum (rockweed) and Laminaria sp. by a few small companies in Newfoundland.
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Filamentous species of Ulva are ideal for cultivation because they are robust with high growth rates and maintained across a broad range of environments. Temperate species of filamentous Ulva are commercially cultivated on nets which can be artificially ‘seeded’ under controlled conditions allowing for a high level of control over seeding density and consequently biomass production. This study quantified for the first time the seeding and culture cycle of a tropical species of filamentous Ulva (Ulva sp. 3) and identified seeding density and nursery period as key factors affecting growth and biomass yield. A seeding density of 621,000 swarmers m-1 rope in combination with a nursery period of five days resulted in the highest growth rate and correspondingly the highest biomass yield. A nursery period of five days was optimal with up to six times the biomass yield compared to ropes under either shorter or longer nursery periods. These combined parameters of seeding density and nursery period resulted in a specific growth rate of more than 65% day21 between 7 and 10 days of outdoor cultivation post-nursery. This was followed by a decrease in growth through to 25 days. This study also demonstrated that the timing of harvest is critical as the maximum biomass yield of 23.068.8 g dry weight m21 (228.76115.4 g fresh weight m21 ) was achieved after 13 days of outdoor cultivation whereas biomass degraded to 15.567.3 g dry weight m21 (120.2671.8 g fresh weight m21 ) over a longer outdoor cultivation period of 25 days. Artificially seeded ropes of Ulva with high biomass yields over short culture cycles may therefore be an alternative to unattached cultivation in integrated pond-based aquaculture systems.
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Recent food crises and growing concerns about global climate change have placed agriculture on top of the international agenda. governments, international organizations, and civil society groups gathered at the group of eight (g8), the group of twenty finance Ministers and central bank governors (g20) and rio+20 summits in 2012 have recognized a convergence between the dual goals of eradicating hunger and making agriculture sustainable. achieving these goals will require a significant increase in agricultural investment but, more importantly, it will require improving the quality of this investment.
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In addition to striving to meet the United Nations Millennium Development Goals, the global community is also grappling with other pressing and complex challenges such as the widespread economic crisis and the effects of climate change. It is in this context that this edition of The State of World Fisheries and Aquaculture highlights the vital role of fisheries and aquaculture in both food and nutrition security as well as economic expansion.
The sector remains a major supplier of high-quality animal protein and supports the livelihoods and well-being of more than ten percent of the world’s population. International trade in fish has reached new peaks as overall production has continued to rise. Yet, as the document underlines, an array of problems – ranging from the need for more effective governance to that of ensuring environmental sustainability – threatens to undermine the sector’s valuable contribution to alleviating hunger and reducing poverty.
Using the latest available statistics on fisheries and aquaculture, this edition presents a global analysis of the sector’s status and trends. It also examines broader related issues such as gender, emergency preparedness and the ecosystem approach to fisheries and aquaculture. Selected highlights, from ecolabelling and certification to the effects of fisheries management policies on fishing safety, provide insights on specific topics. Finally, the document looks at the opportunities and difficulties for capture fisheries in the coming decades.
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The Status of Kelp Exploitation and Marine Agronomy, with Emphasis on Macrocystis pyrifera, in Chile
Kelp cultivation started in Japan, China and Korea, mainly for human consumption; new applications are still expanding. In Chile, three "wild" Lessonia species and Macrocystis pyrifera are under a strong and increasing pressure of exploitation mainly for alginate production and as a source of feed for abalone. Regulatory restrictions for kelp exploitation and the increased demand for biomass provided a positive environment for the installation of a kelp farming industry. Pilot-production studies demonstrated that 200 tonnes (fresh)/ha/year can be achieved and genetic diversity and breeding studies suggested that this volume could be increased. Kelp disease research is a necessary condition for securing the future development of this industry, as are environmental studies on the impacts of large-scale aquaculture. Beyond the positive bioremediation, ecosystem service effects that kelp farming can provide, especially in a region such as in southern Chile, where intensive salmon and mussel cultivation occurs. Life Cycle Assessment suggests that the energy returns on investment in kelp farming are positive, but more detailed data are still required.
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The People’s Republic of China has a long history of mariculture production. The mariculture industry in China has achieved breakthroughs in the hatchery, nursery and culture techniques of shrimp, molluscs and fish of high commercial value since the 1950s.
The first major development was seaweed culture during the 1950s, made possible by breakthroughs in breeding technology. By the end of the 1970s, annual seaweed production had reached 250 000 tonnes in dry weight (approximately 1.5 million tonnes of fresh seaweed). Shrimp culture developed during the 1980s because of advances in hatchery technology and economic reform policies. Annual shrimp production reached 210 000 tonnes in 1992. Disease outbreaks since 1993, however, have reduced shrimp production by about two-thirds. Mariculture production increased steadily between 1954 and 1985, but has been growing exponentially since 1986, mostly driven by mollusc culture. Mollusc culture in China began to expand beyond the four traditional species (oyster, cockle, razor clam and ruditapes clam) in the 1970s. Mussel culture was the first new industry to emerge, followed by scallop aquaculture in the 1980s. Abalone culture has become a major industry in the 1990s. Traditional oyster and clam culture has also advanced and expanded in recent years. Now more than 30 species of marine molluscs are cultured commercially in China. Because of the rapid development in recent years, mollusc culture has become the largest sector of the Chinese mariculture industry, accounting for 81 percent of the total production by weight.
Therefore, the industrialization level and culture techniques for the major species in China have reached an advanced international level, with some leading the world aquaculture sector. China is also the largest country in mariculture.
Marine aquaculture has grown rapidly over the last decade. Marine cultivable areas in China, which include shallow seas, mudflats and bays, are estimated to occupy more than 1.33 million ha, as most marine plants and animals can be cultivated within the 10 m isobath using current culture technologies. In 2002 the area under cultivation and the output reached 1 352 000 ha and 12.1 million tonnes, respectively.
The principal species cultured in northern China are listed in Table 1.
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The galactans extracted with hot water from Kappaphycus alvarezii, after previous extraction at room temperature, are mainly composed of j-carrageenans (~74%) and l-carrageenans (~3%). However, a significant percentage of these galactans (at least 14%) is composed of sulfated agarans and, possibly, agaran-type sulfated DL-hybrid galactans. These agarans are partially substituted on C-2 or C-4 or disubstituted on both positions of the b-D-galactose units and on C-3 or C-2 and C-3 of the a-L-galactose residues with sulfate groups or single stubs of b-D-xylopyranose, D-glucopyranose, and galactose or with D-glucopyranosyl-(1!4)- D-glucopyranose side chains. Significant quantities of 2-O-methyl- and 3-O-methyl-L-galactose units are also present. A great tendency to retain Ca2+ and Mg2+, in spite of massive treatments with Na+ and K+ salts, was observed. The complexation between agarans and agarans–j-carrageenans through divalent cations and the possible zipper-type carbohydrate–carbohydrate interactions would be two complementary mechanisms of interactions.
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Gambierdiscus toxicus gen. et sp. nov. is described. This is a toxin producing dinoflagellate which was collected in a ciguatera-endemic area. Observations were made using both a light microscope with or without phase-contrast and a scanning electron microscope. This species is distincdve in its antero-posterior compressed body shape, with a circular narrow deep cingulum and a deep hollow sulcus. The theca consists of 33 plates: Po, 3', Oa, 7", 6c, 8s, 6"', 1p, 1"". The plate pattern of this species is characteristic in having extremely reduced precingulars 1" and 7", which are situated between apical 1' and the sulcal excavation and are clearly separate from apical 2" and 4". These features and others indicate that this genus should be assigned to the Heteraulacaceae family. This species is always sessile and attaches to dead coral and seaweed, especially brown alga, Turbinaria ornata J. AGARDH. A large number of this species were taken around the Gambier Islands, French Polynesia, in May 1975.
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