Nonnative Oysters in the Chesapeake Bay (2004) / Chapter Skim
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3. Background on Introduced Species
3. Background on Introduced Species
Pages 28-59
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From page 28... ...
While humans have been transporting marine species for hundreds of years, it has been exceedingly difficult to predict whether a species will become "invasive" (spread from the site of introduction and become abundant; Bergelson, 1994; Crawley, 1989; Kolar and Lodge; 2001; Lohrer et al., 2000; see Appendix I) Most nonnative species do not survive where they are introduced, and few become pests after they are transported to new environments.
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From page 29... ...
(2002b) demonstrated that enhanced species diversity directly increases the resistance of subtidal fouling assemblages to invasion and that surveys in a number of coastal habitats in southern New England also revealed an inverse correlation between resident species richness and the number of nonnative species in those habitats.
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From page 30... ...
Every major marine, freshwater, and terrestrial ecosystem in the United States contains introduced species, and in some ecosystems it is difficult to find a native species (e.g., Cohen and Carlton, 1998~. Nonnative species typically make up a large fraction of the biota of marine and estuarine habitats, largely because of the use of these ecosystems for commerce, fishing, and recreation.
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From page 31... ...
for the transport of nonnative species throughout the world (Naylor et al., 2001~. In some cases the introduced species have become significant competitors with native oysters.
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From page 32... ...
CASE STUDIES OF SHELLFISH INTRODUCTIONS France Commercial oyster landings by French oyster farmers currently rank fourth in the world, behind China, Japan, and Korea with 150,000 metric tons harvested per year. The landings are valued at $280 million and represent 25% of the total gross value of French seafood production.
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From page 33... ...
Presently, the oyster industry is valued at 500 million euros, with more than 4,000 companies and 20,000 direct employees and occupying more than 50,000 acres of state leasing grounds and 10,000 acres of private oyster ponds. Because oyster culture is concentrated in bays and estuaries, usually in rural areas, it has played a critical role in shaping the landscape and stabilizing populations in otherwise economically depressed areas.
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From page 34... ...
edulis production reached 85,000 and 28,000 metric tons, respectively, in 1960, despite a major disease outbreak affecting the flat oyster in 1920 and low C angulata recruitment in the 1930s.
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From page 35... ...
gigas originating from Japan and British Columbia was organized to provide spat to the industry and brood stock to establish new reefs and sanctuaries along the French Atlantic coastline. Introduction of the Japanese Oyster C
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From page 36... ...
The brood stock and spat that generated the present population may be more precisely estimated to be 456 metric tons of brood stock and 3,394 million spat. It should be emphasized that the latter represents 7 years of French hatchery production (500 million spat/year)
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From page 37... ...
At least four invertebrate and three algal species were accidentally introduced during the massive operations even with stringent management. The introduced species have limited biomass and distribution and have negligible impact compared to other invasive species such as the limpet C
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From page 38... ...
The Manila clam showed larger growth rates than the native species R decussatus, a high value, and a high acceptance by consumers.
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From page 39... ...
R philippinarum extensively colonized natural beds in several areas in Europe, leading to an extensive public fishery (65,000 metric tons in 2000)
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From page 40... ...
angasi. The Sydney rock oyster is a native species cultured in estuarine areas and rivers, as well as embayments along the coast of New South Wales and Southern Queensland.
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From page 41... ...
Although rock oyster production reached more than 500 metric tons in the mid-1970s, it began to be overwhelmed by the Pacific oyster, C gigas, which was first found in 1971 (Dinamini, 1991a)
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From page 42... ...
In addition, it provides an example of a shellfish industry largely dependent on hatchery-produced seed that is relevant to the development of aquaculture in the Chesapeake Bay. Historical background Native Oyster Beds Depleted by Fishery The oyster industry on the West Coast of North America started with harvest of natural populations of the native oyster, Ostreola conchaphila.
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From page 43... ...
After passage of the Bush and Callow Acts in 1895, the Washington oyster industry began to aggressively culture the native oyster. Efforts were particularly successful in southern Puget Sound, where more than 1,000 acres of tidelands were leveled and diked for native oyster culture (Lindsay and Simons, 1997~.
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From page 44... ...
An 1875 issue of the Manufacturer and Builder observed: "Every year some 500 carloads of small oysters are transported across the continent, to be brought up in the Pacific." The article further noted, "There appears to be a limit to the growth of any kind of Eastern oyster in Pacific waters; after a certain period, a year and half at the utmost, for some reason as yet not well understood perhaps the meat becoming too large for the shell planted the oyster dies." Between 1887 and 1900, 33,480 bushels of Eastern oysters were shipped annually, constituting 80% of the total oyster production from San Francisco Bay during these years (Gordon et al., 2001~. The availability of more popular Eastern oysters in San Francisco markets severely depressed the value of local oysters shipped from Washington.
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From page 45... ...
From 1872 until the early l900s the Eastern oyster dominated West Coast oyster production, peaking in 1899 with an estimated 1,134 metric tons of shucked oyster meat (Conte et al., 1996~. Urbanization of the San Francisco Bay area degraded water quality, and by 1908 Eastern oyster production had fallen 50%.
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From page 46... ...
During the summer of 1936, Pacific oysters bred successfully in Dabob Bay on the Hood Canal, southern Puget Sound, and Willapa Bay. The resulting adult oysters provided a large brood stock as well as an important source of market oysters to carry through World War II when lapanese seed shipments were halted.
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From page 47... ...
Washington state oyster production was estimated by the Pacific Coast Shellfish Growers Association in 2000 at 35,000 metric tons live weight. Most of the production consisted of C
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From page 48... ...
, and importation of Japanese seed ended around 1961. As in Washington state and the rest of the North American West Coast, the British Columbia industry today has transitioned to a significant reliance on hatchery-produced Pacific oyster seed.
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From page 49... ...
Washington and British Columbia have areas where natural spatfall occurs. In these areas (Willapa Bay and Hood Canal in Washington, Pendrell Sound and the Strait of Georgia in British Columbia)
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From page 50... ...
, Totten and Eld inlets (southern Puget Sound) , and Willapa Bay suggests that oyster seed shipments from Japan and the U.S.
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From page 51... ...
It reproduces successfully in a number of areas in Puget Sound, Willapa Bay, and British Columbia. Production in 2000 in Washington state alone was estimated by the Pacific Coast Shellfish Growers Association to be in the neighborhood of 7 million pounds valued at $14 million.
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From page 52... ...
It first gained a solid foothold in British Columbia waters between 1941 and 1945 (Quayle, 1988~. It is thought to have been introduced to the Puget Sound in the 1930s with Pacific oyster seed.
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From page 53... ...
Spartina has also infested parts of Puget Sound but was more likely deliberately introduced by duck hunters as a duck blind or by cattle operations as an alternative food that would grow well in the salty soil recovered by building dikes in the bays. Although many nonnative species were probably introduced to the West Coast with foreign oyster seed, only one significant disease is thought to have resulted from such shipments.
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From page 54... ...
In notably warm years successful breeding continues to occur in certain areas of Washington and British Columbia; however, the Pacific oyster fails to breed over most of the West Coast of North America, limiting its ability to invade new areas. · There were few or no protections to prevent unintentional species or disease introductions with oyster seed imports from the East Coast or Japan until 1945.
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From page 55... ...
gigas in France occurred after an estimated 562 metric tons of adults and several billion spat were imported and planted between 1971 and 1975 (Grizel and Heral, 1991~. Further, naturally occurring populations of C
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From page 56... ...
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From page 58... ...
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From page 59... ...
gigas, led to revitalization of the oyster industry, but in New Zealand and Australia, the Pacific oyster outcompeted the commercially viable native oyster in some areas. · The oyster industry on the U.S.
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