Showing papers on "Oyster published in 1971"
TL;DR: Over a period of 6 weeks in aquaria, Portuguese oysters Crassostrea angulata, accumulate 65Zn to a greater extent than do native Ostrea edulis, although intake rates for any particular organ in either species are quite similar.
Abstract: Over a period of 6 weeks in aquaria, Portuguese oysters Crassostrea angulata, accumulate 65Zn to a greater extent than do native Ostrea edulis, although intake rates for any particular organ in either species are quite similar. The general distribution pattern of radioactivity in the tissues is similar to that observed for stable zine and 65Zn in other oyster species, concentration occurring to the greatest extent in gills and mantle, and least in muscle. The observed equilibrium concentrations and biological half-lives are considerably less than those measured in the natural environment, and the significance of this and its bearing on the mechanism of uptake is discussed. Cobalt and iron depress the rate of 65Zn uptake by both oyster soft tissues and the shell. The limiting effect in soft tissues is probably due to competition for sites at the actual point of uptake. The distribution of 65Zn in tissue subcellular fractions separated by centrifugation shows the greatest concentration of the radioisotope in the insoluble tissue components of gills, mantle and heart. Appreciable amounts of 65Zn are associated with tissue proteins.
71 citations
59 citations
TL;DR: A substance which stimulates the gregarious setting of oyster larvae has been partially purified and these same substances are associated with the biological activity as they too will stimulate setting of larvae, although much higher concentrations are necessary for activity comparable to that of the conjugate protein.
Abstract: A substance which stimulates the gregarious setting of oyster larvae has been partially purified. This material, which is present in the oyster shell liquor, is a protein of molecular weight in excess of 100,000 Daltons. Thyroxine, and possibly 3,5-diiodotyrosine and 3-iodotyrosine are freed by enzymatic or alkaline hydrolysis of the protein. These same substances are associated with the biological activity as they too will stimulate setting of larvae, although much higher concentrations are necessary for activity comparable to that of the conjugate protein.
55 citations
54 citations
TL;DR: It is indicated that the unspecialized monocyte-type agranular amebocytes observed in amebocyte plugs from early wounds may have differentiated into the fibroblasts and myoblasts typical of late wounds (144- and 240-hr-old wounds).
54 citations
TL;DR: Crassostrea gigas (Thunberg), the Japanese oyster, is recorded for the first time in New Zealand and may have been introduced accidentally.
Abstract: Crassostrea gigas (Thunberg), the Japanese oyster, is recorded for the first time in New Zealand. This exotic species may have been introduced accidentally.
35 citations
TL;DR: In these experiments, accumulation by direct absorption alone cannot account for the large concentration factors implied from field assays of 51 Cr in Columbia River organisms.
33 citations
TL;DR: Respiration rates of gill and mantle declined by about 17% in the autumn, while adductor muscle respiration increased by about 14%.
Abstract: Respiration rates of excised gill, mantle, and adductor muscle of the American oyster, Crassostrea virginica (Gmelin), were measured by the Warburg technique at a number of temperatures and salinities and at various times during the year. Dilution of the seawater medium stimulates gill respiration, has no significant effect on mantle respiration and inhibits adductor muscle respiration. Rate–temperature curves are presented for all three tissues. Respiration rates of gill and mantle declined by about 17% in the autumn, while adductor muscle respiration increased by about 14%. A number of possible explanations for the seasonal changes are discussed.
23 citations
TL;DR: Bay beds were badly depleted whereas certain rivers showed potential as seed areas, and the association of high oyster production with a hard shell substrate was demonstrated which emphasized the need for a regular shell planting program.
Abstract: Delaware oyster beds in the Bay and associated tributaries were studied from 1968 to 1970 to determine their general condition following mass mortalities from MSX (Minchinia nelsoni) during the late 1950's and 1960's. Estimates of standing crop of oysters yielded a total of 54,582 bushels covering 236.9 acres (95.9 hectares) in the river beds and 65,482 bushels covering 941 acres (380.8 hectares) in the bay beds. Bay beds were badly depleted whereas certain rivers showed potential as seed areas. The association of high oyster production with a hard shell substrate was demonstrated which emphasized the need for a regular shell planting program. Spat monitoring indicated that setting occurred in two waves and extended from July 4 to early in September. River mouths generally received the heaviest set. Since there has been practically no oystering in Delaware for twelve years, an experimental planting of seed on three planted beds was carried out in 1969–1970. Although all the experimental beds were...
17 citations
TL;DR: In this paper, the operation of a prototype (24-bushel capacity) depuration plant for the bacteriological cleansing of oysters was evaluated under prevailing Gulf Coast environmental conditions, and the results indicated that with proper plant location and basic engineering design of the system, commercial depuration of shellfish is a feasible method for purifying oysters harvested from restricted waters.
Abstract: The operation of a prototype (24-bushel capacity) depuration plant for the bacteriological cleansing of oysters was evaluated under prevailing Gulf Coast environmental conditions. Results indicated that with proper plant location and basic engineering design of the system, commercial depuration of shellfish is a feasible method for purifying oysters harvested from restricted waters. Eight trials were conducted over a 15-month period to cover seasonal changes. The depuration tank design permitted three pallets, each holding 16 baskets of one-half bushel capacity, to be stacked in the tank. A fecal coliform MPN of 130 or less/100 g for depurated oysters was established as the maximum level of acceptability for a 72 hour period of depuration. Physical parameters of the sea water which were measured included salinity, temperature, turbidity, pH, and dissolved oxygen. Determinations of the percent wet/dry weight and percent glycogen of depurated oyster meats revealed no adverse effect on quality.
30 Jul 1971
TL;DR: In this article, it was found that drilling fluid reduced the survival of oysters to a significant degree in concentrations above 200 ppm and at turbidities between 200 and 500 ppm, there was 50% survival on the seventh day.
Abstract: In 1965, 970.12 m3 of oil drilling fluid were spilled in the Laguna de Tamiahua, Mexico. Laboratory experiments were carried out to determine possible effects of this upon the oyster Crassostrea virginica. It was found that drilling fluid reduced the survival of oysters to a significant degree in concentrations above 200 ppm. At turbidities between 200 and 500 ppm, there was 50% survival on the seventh day. Tunino in concentrations between 90 and 170 ppm had a drastic effect upon survival which was 50% between the fourth and fifth days. Bentonita in 110 to 190 ppm resulted in 50% survival on the eighth day. Barita in concentrations between 50 and 65 ppm did not produce noxious effects on the survival of the oysters. Natural mud in concentrations from 200 to 500 ppm was favorable for the survival of oysters.
Patent•
23 Sep 1971
TL;DR: In this paper, a plurality of seed oysters are provided and a cement other than that excreted by the oyster seed is used to secure the seed to the member.
Abstract: Apparatus for growing oysters in sea water comprising a member mounted in sea water so that it is above the bottom level of the sea water at all times and below the top surface of the sea water for a substantial period of each 24 hours. A plurality of seed oysters are provided and a cement other than that excreted by the oyster seed secures the oyster seed to the member. The oysters are arranged in a predetermined pattern and are spaced in such a manner that the oysters can grow to a substantially larger size on the member without deforming each other. In the method, a member is positioned in the sea water so that it is disposed above the bottom level of the sea water and for a substantial period of time of each 24 hours, below the top surface of the sea water. Seed oysters are secured to the member using an adhesive and the oysters are arranged in a predetermined pattern and are spaced in such a manner so that they can grow to a substantially larger size without deforming each other.
Journal Article•