Showing papers on "Oyster published in 1994"
TL;DR: The oyster population in the Maryland portion of the Chesapeake Bay, USA, has declined by more than 50 percent since the early part of this century as discussed by the authors, due to habitat loss associated with intense fishing pressure early in this century.
Abstract: The oyster population in the Maryland portion ot Chesapeake Bay, USA, has declined by more than 50-Iold since the early part of this century. The paper presents evidence that the mechanical destruction of habitat and stock over fishing have been important factors in the decline, even thouqh it is commonly thought that 'water quality' and, more recently, oyster diseases are critical. Quantitative analyses show that the long-term decline 01 oysters largely resuIts from habitat loss associated with intense fishing pressure early in this century and stock over fishing from early in the century throuqh recent limes. Furthermore, the major ecological effects on Chesapeake Bay occurred weIl betore World War II, before industrialization and the reported prevalence of disease. To effect the recovery of the ailing Chesapeake Bay oyster stock, a 4-point management strategy is proposed.
468 citations
TL;DR: Adding bacteria (strain CA2) as a food supplement to xenic larval cultures of the oyster Crassostrea gigas consistently enhanced growth of larvae during different seasons of the year.
194 citations
TL;DR: Molecular data from domains D1, D2, and partial D3 of the 28S rDNA supply sufficient phylogenetic information to determine systematic relationships among the extant oyster taxa, from the major species groups to the family level, thus providing valuable characters that are able to supplement the paucity of morphological characters so far recognized.
175 citations
TL;DR: This investigation provides the first experiimental evidence to demonstrate that dissolved chemical cues can mediate settlement by larvae under hydrodynamic conditions approaching those of natural benthic habitats.
Abstract: Although previous evidence indicates that larvae of benthic marine invertebrates can respond to waterborne cues in still water, the importance of waterborne cues in mediating natural settlement out of flowing water has been questioned. Here, we summarize the results of flume experiments demonstrating enhanced settlement of oyster larvae in small target wells (circles of 7-cm diam) with the release of a waterborne settlement cue compared to identical substrates without the cue. In concurrent still-water experiments, more oyster larvae settled in solutions of waterborne cue than in seawater controls. Velocity and electrochemical measurements of a conservative tracer verified that at low flow velocities (2 and 6 cm s-l) with U, values ~0.25 cm s-l, the waterborne cue was present above the targeted substrate to a height of 14 mm. Rapid vertical swimming or sinking in response to the waterborne cue can concentrate larvae in near-bottom waters and enhance larval settlement. Our investigation provides the first experiimental evidence to demonstrate that dissolved chemical cues can mediate settlement by larvae under hydrodynamic conditions approaching those of natural benthic habitats.
162 citations
Journal Article•
TL;DR: Observations with transmission electron microscope showed the presence of herpes-like virus particles in infected larvae and young spats, and the viruses observed in diseased larvae and affected young spat oysters were very similar.
Abstract: Sporadic mortalities were reported in june and july of 1992 and 1993 among batches of hatchery-reared larval Pacifie oyster, Crassastrea gigas, and at the beginning of July and in August of 1993 among five batches of 3-7 month old young spats, C gigas Observations with transmission electron microscope showed the presence of herpes-like virus particles in infected larvae and young spats The viruses observed in diseased larvae and affected young spat oysters were very similar Elevated temperature and crowding may increase susceptibility of oysters to these herpes-like virus infections
146 citations
Journal Article•
TL;DR: During the summer of 1993, abnormal sporadic mass mortalities and morbidities occurred among four batches of young Japanese oyster (Crassostrea gigas) spat from the French Atlantic coast.
Abstract: During the summer of 1993, abnormal sporadic mass mortalities (80-90%) and morbidities occurred among four batches of young Japanese oyster (Crassostrea gigas) spat from the French Atlantic coast. These mortalities were only observed in July. Samples of affected animaIs were examined by electron microscopy. This paper reports the presence and appearance of herpes viruses in these samples.
127 citations
TL;DR: Suspension-feeding processes in the eastern oyster Crassostrea virginica were examined, in vivo, with an endoscope linked to a video image-analysis system, finding that previously published concepts of particle transport and processing in this species are incomplete or inaccurate.
Abstract: Suspension-feeding processes in the eastern oyster Crassostrea virginica (Gmelin, 179 1) were exam- ined, in vivo, with an endoscope linked to a video image- analysis system. We found that many of the previously published concepts of particle transport and processing in this species, obtained using surgically altered specimens or isolated organs, are incomplete or inaccurate. In par- ticular, our observations demonstrate that (1) captured particles are transported along the gills by both mucocil- iary (marginal grooves) and hydrodynamic (basal tracts) processes; (2) the labial palps accept material from the gills both in mucus-bound particle strings (transported in marginal grooves), and suspended in particle slurries (transported in basal tracts); (3) the labial palps reduce the cohesive integrity of the mucous strings and disperse and sort the entrapped particles; (4) particles are ingested in the form of a slurry; and (5) ciliary activity on the labial palps is independent of that on the lips, allowing the oyster to filter particles from suspension and produce pseudo- feces without ingesting any particulate matter. Because many ostreids have the same plicate gill structure, we be- lieve that our conclusions are applicable to other oyster species. In addition, the present observations are consis- tent with other endoscopic examinations recently made on bivalves in different families. We conclude that ac- cepted theories of particle handling in suspension-feeding bivalve mollusks must be modified to accommodate ob- servations made with the endoscope.
115 citations
TL;DR: The effect of a complex mixture of sediment derived pollutants on the susceptibility of the eastern oyster, Crassostrea virginica, to an infectious disease was investigated and enhanced preexisting P. marinus infections and increased the oysters' susceptibility to experimentally induced infection, in a dose-dependent manner.
98 citations
TL;DR: The effects of mercury (Hg) concentrations upon embryogenesis, survival, growth, growth and metamorphosis of Crassostrea gigas (Thunberg) oyster larvae were investigated and growth, the most sensitive physiological process studied, was significantly retarded.
Abstract: The effects of mercury (Hg) concentrations ranging from 0 (control) to 1024 µg 1-1 upon embryogenesis, survival, growth and metamorphosis of Crassostrea gigas (Thunberg) oyster larvae were investigated. Embryogenesis was abnormal in 50 % of the individuals at 11 µg 1-1 . The 48 h LD50 for D·shaped, umbonate and pediveliger larvae were 33, 115 and 200 µg 1-1 respectively. The increase in LD50 was partially explained by the larval weight increase, although weight-specific tolerance to Hg was higher in smaller larvae. Growth, the most sensitive physiological process studied, was significantly retarded at 4 µg 1-1. The metamorphosis rate was significantly reduced when competent pediveligers were exposed to 64 µg 1-1 for 48 h prior to the addition of the metamorphosis inducer epinephrine. The implications of the present results for monitoring pollution by utilising different bivalve larval stages are discussed.
92 citations
TL;DR: In this paper, the abundances of the xanthid crabs Panopeus herbstii and Eurypanopeus depressus were examined relative to surface shell cover, surface oyster cluster volume, subsurface shell content, substrate sand and silt composition, and oyster reef elevation.
Abstract: The abundances of the xanthid crabsPanopeus herbstii andEurypanopeus depressus were examined relative to surface oyster shell cover, surface oyster cluster volume, subsurface shell content, substrate sand and silt composition, and oyster reef elevation. During August 1986 through July 1987, xanthid crabs were collected monthly from twelve 0.25 m2×15 cm deep quadrats, during low tide, from intertidal oyster reefs in Mill Creek, Pender County, North Carolina, USA, with respective quadrat details recorded. The abundance ofP. herbstii, and to a lesser degreeE. depressus, was positively correlated with surface shell cover. The abundance ofE. depressus, and to a lesser degreeP. herbstii, was positively correlated with surface cluster volume. The majority ofP. herbstii inhabited the subsurface stratum of the oyster reef, whereas the majority ofE. depressus inhabited the cluster stratum. Seasonality (i.e., temperature) appeared to influence the strata habitation of both species, with a higher incidence of cluster habitation during warmer months and a lower incidence during colder months. Crab abundance was not related to other factors examined, such as subsurface shell, substrate sand and silt composition, or elevation within the oyster reef. The analyses show thatP. herbstii andE. depressus have partitioned the intertidal oyster reef habitat, withE. depressus exploiting surface shell clusters andP. herbstii the subsurface stratum.
90 citations
Journal Article•
TL;DR: Comparisons of adult size and reproductive effort between oyster populations can only be made within the context of a complete environmental analysis of food supply and associated physical parameters and an energy flow model.
Abstract: A time-dependent model of energy flow in post-settlement oyster populations is used to examine the factors that influence adult size and reproductive effort in a particular habitat, Galveston Bay, Texas, and in habitats that extend from Laguna Madre,. Texas to Chesapeake Bay. The simulated populations show that adult size and reproductive effort are detennined by the allocation of net production to somatic or reproductive tissue development and the rate of food acquisition, both of which are · temperature dependent. For similar food conditions, increased temperature reduces the allocation of net production to somatic tissue and increases the rate of food acquisition. This temperature effect, however, is mediated by changes in food supply. Within the Gulf of Mexico, oyster size declines from north to south because increased temperature deer.eases the allocation of net production to somatic growth. An increase in food supply generally results in increased size as more energy is used in somatic growth; however, at low latitudes, as food supply increases, adult size decreases because the allocation of more net production to reproduction outweighs the -effect of increased rates of food acquisition. Variations in temperature and food supply affect reproductive effort more than adult size because the rate of energy flow through the oyster is higher in wanner months when most net production is allocated to reproduction and small changes in temperature substantially change the spawning season. The wide range of reproductive effort expected from small changes in temperature and food supply suggest that comparisons of adult size and reproductive effort between oyster populations can only be made within the context of a complete environmental analysis of food supply and associated physical parameters and an energy flow model.
TL;DR: It is shown that predation by P herbstii inflicted the greatest mortality on mussels of intermediate (20 to 40 mm shell length) size because larger mussels have a refuge in size and small mussels has a spatial refuge within the interstices of oyster clumps.
Abstract: The predatory xanthid crabs Eurytjum limosurn and Panopeus herbstii are common components of benthic assemblages in different intertidal habitats within salt marshes around Sapelo Island. Georgia, USA. E. limosum feed primarily on other crabs and are found where cordgrass Spartina altemiflora stems are the dominant structural elements in the environment. P: herbstii feed largely on bivalve molluscs and are abundant in intertidal creeks where oyster Crassostrea virginica reefs are the predominant structural elements. We designed laboratory experiments to measure prey consumption rates by these 2 predators under conditions that simulated those experienced by each species in its respective habitat. Biogenic structure within the environment of each species reduced prey consumption rates. The mean (i. SD) number of fiddler crabs Uca puynax killed in 24 h by E. limosum was less (2.0 t 0.87 individuals) in the presence of stems than in their absence (2.9 + 1.63 individuals). Fiddler crabs had no refuge in size from predation by E. limosum. However, mortality rates of fiddler crabs exposed to predation by E. lirnosum were sex-dependent. Males of U. pugnax sometimes escaped the predator's grasp by autotomizing their prominent major chela and consequently when prey were offered in an equal sex ratio significantly (paired t-test, p = 0.03) fewer males (4.3 f 2.55) than females (5.7 + 2.65) were killed by E. limosurn in 48 h. We believe that predation by mud crabs may contribute to male-biased sex ratios that are commonly observed in natural populations of fiddler crabs. Oyster shell clumps influenced the predator-prey interaction between P herbstil and the ribbed mussel Geukensia dernissa In a simulated intertidal creek environment. Mussels attached to the exterior (exposed) surfaces of an oyster clump suffered a 3.5 times greater mortality than those attached to the inside (concealed) surface of the clump. Results of previous studies in whlch prey were offered as isolated individuals suggest that k? herbstii should have the greatest impact on small (<20 mm shell length) mussels. However, by simulating natural conditions, we showed that predation by P herbstii inflicted the greatest mortality on mussels of intermediate (20 to 40 mm shell length) size because larger mussels have a refuge in size and small mussels have a spatial refuge within the interstices of oyster clumps. Our findings suggest that xanthid crabs have a greater impact within salt marsh communities than previously recognized and emphasize the importance of using 'context-sensitive' experiments to explore predator-prey interactions.
TL;DR: In general, cytochrome P450 content, NADPH-cytochrome c (P450) reductase and microsomal NAD(P)H-dependent DT-diaphorase activities correlated well with tissular PAHs concentrations, whereas a certain correlation between glutathione peroxidase (GPX) activity and organochlorinated compounds accumulation was also detected.
TL;DR: Triploid Sydney rock oysters can reach market size 6–18 months faster and maintain better meat condition than diploid oysters without an increased risk of winter mortality, have major implications for the N.S.W. oyster industry.
TL;DR: Histological examination revealed infections with Bonamia ostreae in 34 and 45% of the flat oysters from Maine and in 31 and 12% of those from California, and the history of oyster movements between geographic locations suggested that the source of bonaniasis inflat oysters in Maine was infected flat oyster from California.
Journal Article•
TL;DR: This method is the first report of a successful experimental transmission of a viral diseasc affecting bivalve molluscs and develops a method for diagnosis and production of C. XiXas to shellfish culture.
Abstract: Summary A herpes-like virus associatcd with mortalities among hatchery rearcd larvae of Pacifie oyster. Crassoslrca XiXas. has been described in France and New Zealand. Considering the economic importance of C. XiXas to shellfish culture, we have dcveloped a method for diagnosis and production of C. gigas herpes-Iike virus on axenic C. giXas larvae. The virus spreads quite quickly: 100% larvae showed lesions within 48h post infection. and cumulative mortalities reached 100% on the sixth day p.i. Ultrastructural examination revealed the presence of the same viral particles as previously described in infectcd larvae from hatcherics. Virus stoch werc still infectious aftcr being stored at -20°C for several months. Wc failed to obtain infcction of fiaI 0ysler, Oslrca cdulis. larvae. This method is the first report of a successful experimental transmission of a viral diseasc affecting bivalve molluscs. Authors address * IFREMER. Unite de Recherche cn Pathologie et Immunologie Generales, B.P. 133. 17390 La Tremhladc, France.
TL;DR: It is concluded that oysters have the ability to feed at nearly all stages of settlement and metamorphosis and that hypoxic conditions will affect the feeding activities of only the youngest post-settlement oysters while microxic conditions will affected all post- settling oysters.
TL;DR: It is concluded that low oxygen conditions, in particular those that are microxic and last longer than 24 h , have detrimental effects on the development, growth, and mortality of postsettlement oysters.
Abstract: Four phases of metamorphosis in the eastern oyster Crassostrea virginica were characterized: 'settlers' have attached to the substrate but retain larval characteristics; metamorphosis and degeneration of the velum has begun in 'prodlssoconch postlarvae'; in 'dissoconch postlarvae' shell growth beyond the prodissoconch has begun but the foot persists; and 'juveniles' have lost all larval organs and metamorphosis 1s complete. These phases were used in exarmning the metamorphic process dunng and following continuous and short-term exposures to hypoxia (1.5 mg 0, I ' , 20% of air saturation) and microxia (<0.07 mg O2 1-l, < 1 % of air saturation) We observed no abnormal development in the oysters, but development was delayed following 3 d exposures to hypoxia, and 2 and 3 d exposures to microxia. Under continuous exposure to microxia, oysters did not develop to the dlssoconch postlarva or juvenile phases Approximately 50% of the control oysters died within the 2 wk penod following settlement I\?ortality was virtually confined to the settler and prodissoconch postlarva phases. Short-term exposures to hypoxia ( l to 3 d) and microxia (1 d) had little effect on the median mortality time or final total mortality, compared to controls. Microxic treatments longer than 1 d did affect mortality and oysters continuously exposed to rnicroxia had a median mortality tune of 87 h . Short-term exposures to low oxygen did not have permanent effects on post-settlement growth rates. Oysters exposed to microxic treatments, however, appeared to have slower growth rates dunng the exposure penod. We conclude that low oxygen conditions, In particular those that are microxic and last longer than 24 h , have detrimental effects on the development, growth, and mortality of postsettlement oysters.
TL;DR: A positive correlation between oyster size and the estimated days to spawn suggests that larger oysters require longer to prepare to spawn, and the range in observed somatic and gametic growth emphasizes the conservatism of somatic growth and the volatility of gonadal growth that is borne out by the results of population dynamics models of oysters.
Abstract: An immunoprecipitation assay was developed for measuring instantaneous reproductive effort in female American oysters, Crassostrea virginica. Oysters were in- jected with 14C-leucine and incubated in situ for 1 to 30 h periodically throughout the annual gametogenic cycle. Gonadal protein labeled with 14C-leucine was precipitated from an oyster homogenate with rabbit anti-oyster egg IgG as the primary antibody. Antibody-oyster egg protein complex was further purified by immunoadsorption with staphylococcal protein A cell suspension. The quantity of oyster eggs was determined by single-ring immunodiffu- sion. A mathematical model was developed to calculate the instantaneous reproductive rate of oysters and to es- timate the number of days required from the initiation of gonadal development to spawning. The oyster popu- lation was lightly to moderately infected with a protozoan parasite, Perkinsus marinus. A negative correlation be- tween the intensity of infection and the rate of gonadal production suggests that P. marinus retards the rate of gamete development. The seasonal cycle of gamete pro- duction determined by direct measurements of egg protein production was not equivalent to that determined by standard gonadal-somatic index (GSI), except at the most basic level. GSI was highest during the spring spawning peak, but the rate of gamete production was highest in the fall. Accordingly, the two measurements, rate versus
TL;DR: The benefits of group foraging for individuals in the marine gastropod Stramonita (=m&) haemastoma, which preys on the oyster Crassostrea virginica along the coast of Louisiana, USA, are studied.
Abstract: We studied the benefits of group foraging for individuals in the marine gastropod Stramonita (=m&) haemastoma, which preys on the oyster Crassostrea virginica along the coast of Louisiana, USA. From 40 to 58 % of the snails at 2 sites on 2 dates were feeding with at least 1 additional snail, suggesting group feeding occurs frequently in the field. In the laboratory, we studied the feeding of solitary foragers as well as groups of 4 snails, and found that, for snails feeding in groups on both small (<70 g wet mass) and large oyster prey, per capita feeding rates actually decreased. However, the fraction of tissue removed per oyster was on average 21 % greater for the snails feeding in groups. resulting in similar per capita oyster tissue consumption rates and growth rates for solitary and group foragers. Inter-feeding intervals also decreased for snails feeding in groups. Oyster-handling times were similar for snails feeding in groups and for solitary snails, indicating little benefit in subduing prey, but handling times did increase with prey size, suggesting large oysters may be more difficult to consume. Feeding rates and percent consumption were also lower for large oysters, and snails fed in larger groups when feeding on larger oyster prey. In the group feeding treatment, snails joined oysters already under attack much more frequently than they initiated an attack, joined with others to initiate an attack, or fed alone. These trends were also more pronounced for snails feeding on larger prey, and most snails pursued a mixed strategy, both initiating and joining oyster prey. Most additional foragers joined early in the foraging bout. We suggest several explanations for the existence of group foraging: not that it increases individual feeding rates, but that it occurs instead because (1) there is no measur- able cost in rates of tissue consumption for individuals feeding in groups, (2) not all oyster tissue can be removed by solitary foragers, (3) there is no mechanism available for snails to defend a prey, and (4) it may provide a mechanism for handling larger oyster prey.
TL;DR: Between 1985 and 1992, mortality due to infestation by the protistan Bonamia sp.
Abstract: Between 1985 and 1992, mortality due to infestation by the protistan Bonamia sp. severely reduced the numbers of the oyster, Tiostrea chilensis in Foveaux Strait, New Zealand. In 1990, two dredge surveys gave relative estimates, and a dive survey an absolute estimate, of the size of this oyster population; this allowed us to estimate dredge efficiency precisely. This estimate was used to re‐evaluate the dredge survey of 1975–76 and relate the size of the population in 1990 to that in 1975. By 1990 the population density had declined by 67% while a dredge survey in 1992 showed that the population density had declined by 91% from 1975. A dredge survey in 1993 showed that the population had increased slightly (but not significantly) over the 1992 level. By 1992 the population had probably been reduced below 10% of the virgin level. The fishery was closed in 1993 to allow the population to rebuild. The population surveys have followed stratified random and grid pattern sampling designs and the merits...
TL;DR: P mannusis a potential source of oyster mortality in these coastal lagoons; more intensive sampling is necessary to determine the mortality attributable to P madnus.
Abstract: Poorly documented, but apparently sporadic oyster Crassostl-ea v~rginjca mortality in the coastal lagoons Carmen, Machona and Mecoacan at the southern extreme of the Gulf of Mexico inTabasco, Mexico, has been attributed by local oystermen to pollution resulting from oil refinery operations. In September 1992 we sampled oysters in these lagoons to investigate the potential for disease-induced mortality from the oyster pathogen Perkinsus marinus. Prevalence of P marinus was 100% at Lodazal, a high salinity (31 ppt) site in Carmen lagoon and 60% at Rio San Felipe, a low salinity (15 ppt) site. At Los Jimenez. a high salinity (32 ppt) site in Machona lagoon with previous high mortality, prevalence of P marinus was 90% and weighted prevalence, a measure of intensity, was 3.1, a high value associated with heavy infections and mortality. Samples collected at the Buena Vista aquaculture facility in Mecoacan lagoon revealed 60 to 100 % prevalence of P marinus, although most infections were low intensity. P mannusis a potential source of oyster mortality in these coastal lagoons; more intensive sampling is necessary to determine the mortality attributable to P madnus.
TL;DR: In this article, the authors compared four methods for drying oyster soft tissues: oven-drying at 105, 100, 80°C and freeze-doughnut drying, and found that the average ratio of wet to 5-day dry weight ranged from 9.07 to 9.47 for ovendrying, but was only 7.35 for freezedrying.
TL;DR: It is shown that there remains considerable scope to improve the conditions for broodstock maintenance for aquaculture purposes, as oysters pre-conditioned in fertilised sea water for 42 days prior to warm-water conditioning in the hatchery produced more broods of larvae than oyster pre- conditioned in unfertilisedSea water.
Journal Article•
TL;DR: Simulations showed that oyster populations are more susceptible to population declines when mortality is restricted to the summer months, and management decisions on size limits, seasons and densities triggering early closure must differ across the latitudinal gradient.
Abstract: -:A time-dependent energy-flow model was used to examine how mortality affects oyster populations over the latitudinal gradient from Galveston Bay, Texas, to Chesapeake Bay, Virginia. Simulations using different mortality rates showed that mortality is required for market-site oysters to be a component of the population's size-frequency distribution; otherwise a population of stunted individuals results. As mortality extends into the juvenile sizes, the population's size frequency shifts toward the larger sizes. In many cases adults increase despite a decrease in overall population abundance. Simulations, in which the timing of mortality varied, showed that oyster populations are more susceptible to population declines when mortality is restricted to the summer months. Much higher rates of winter mortality can be sustained. Comparison of simulations of Galveston Bay and Chesapeake Bay showed that oyster populations are more susceptible to intense population declines at higher latitudes. The association of population declines with disease agents causing summer mortality and the increased frequency of long-term declines at high latitudes result from the basic physiology of the oyster and its population dynamics cycle. Accordingly, management decisions on size limits, seasons and densities triggering early closure must differ across the latitudinal gradient and in populations experiencing different degrees of summer and winter mortality relative to their recruitment rate. More flexible size limits might be an important management tool. When fishing is the primary cause of mortality, populations should be managed more conservatively in the summer. The latitudinal gradient in resistance to mortality requires more conservative management at higher latitudes and different management philosophies from those used in the Gulf of Mexico. Manuscript accepted 12 October 1993 Fishery Bulletin 92:347-373 (1994) Modeling oyster populations. IV: Rates of mortality, population crashes, and management*
TL;DR: In this article, two temporally separate larval fish assemblages were identified from ichthyoplankton samples collected between November 1987 and January 1990 along a transect from offshore to Oyster Bayou tidal pass into Four League Bay, Louisiana.
Abstract: Two temporally separate larval fish assemblages were identified from ichthyoplankton samples collected between November 1987 and January 1990 along a transect from offshore to Oyster Bayou tidal pass into Fourleague Bay, Louisiana. The warm water species (e.g. bay anchovy, naked goby, Microgobius sp., spotted seatrout and skilletfish) dominated in water temperatures >23 °C and the cooler water species (e.g. gulf menhaden and Atlantic croaker) dominated in water temperatures <23 °C. These assemblages were characterized by different life-history strategies, distributions, and seasonal abundances suggesting that they utilize resources in different locations and times. Analysis of Oyster Bayou tidal pass data indicated that larvae from all species were more abundant on flood than ebb tides and larval fish densities were often statistically greater near bottom, suggesting tidal transport and/or retention. In addition, larger larval bay anchovy and gulf menhaden were taken in the middle of the tidal pass during flood tides. During ebb tides, however, larger bay anchovy larvae were taken along the pass edges, suggesting behaviourally mediated transport into and/or retention within the estuary.
TL;DR: Survival was higher when DMSO was combined with acetamide than when using D MSO or acetamide alone at high concentration (5 M), and the use of trehalose or glucose reduced toxicity of high cryoprotectant concentrations.
01 Jan 1994
TL;DR: The abundance of Eurypanopeus depressus and Panopeus herbstii was positively correlated with surface shell cover and surface cluster volume in the intertidal oyster reef as mentioned in this paper.
Abstract: The abundances of the xanthid crabs Panopeus herbstii and Eurypanopeus depressus were examined relative to surface oyster shell cover, surface oyster cluster volume, subsurface shell content, substrate sand and silt composition, and oyster reef elevation. During August 1986 through July 1987, xanthid crabs were collected monthly from twelve 0.25 m2 X 15 cm deep quadrats, during low tide, from intertidal oyster reefs in Mill Creek, Pender County, North Carolina, USA, with respective quadrat details recorded. The abundance of P. herbstii, and to a lesser degree E. depressus, was positively correlated with surface shell cover. The abundance of E. depressus, and to a lesser degree P. herbstii, was positively correlated with surface cluster volume. The majority of P. herbstii inhabited the subsurface stratum of the oyster reef, whereas the majority of E. depressus inhabited the cluster stratum. Seasonality (i.e., temperature) appeared to influence the strata habitation of both species, with a higher incidence of cluster habitation during warmer months and a lower incidence during colder months. Crab abundance was not related to other factors examined, such as sub- surface shell, substrate sand and silt composition, or elevation within the oyster reef. The analyses show that P. herbstii and E. depressus have partitioned the intertidal oyster reef habitat, with E. depressus exploiting surface shell clusters and P. herbstii the subsurface stratum.
01 Jul 1994-Comparative Biochemistry and Physiology Part C: Pharmacology, Toxicology and Endocrinology
TL;DR: The results indicate that copper is a potential environmental immunotoxicant for mollusks, imparing the ability of the cells to mount a typical protective response.
TL;DR: The content of cholesterol in the serum and liver of male Wistar rats fed, for the period of 8 weeks shortly after weaning, a diet containing 0.3% of cholesterol was reduced by 33 and 27% by the addition of 5% of dried oyster mushroom powder.
Abstract: The content of cholesterol in the serum and liver of male Wistar rats fed, for the period of 8 weeks shortly after weaning, a diet containing 0.3% of cholesterol was reduced by 33 and 27% by the addition of 5% of dried oyster mushroom powder. Although the level of serum triacylglycerols was not affected by oyster mushroom, their content in liver of rats on mushroom diet was reduced by 41%. Very-low-density lipoproteins and low-density lipoproteins participated by 55 and 38%, respectively, in the total reduction of serum cholesterol. Cholesterol content in high-density lipoproteins was not significantly affected by oyster mushroom. Cholesterol absorption as determined by dual-isotope plasma ratio method was significantly reduced by 14% with oyster mushroom diet. Similarly, this diet increased by 42% the fractional catabolic rate of cholesterol determined by the analysis of decay curve of [4−14C]cholesterol.