Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
3,282
result(s) for
"oyster culture"
Sort by:
Development and Evaluation of High-Density SNP Arrays for the Eastern Oyster Crassostrea virginica
Abstract The eastern oyster Crassostrea virginica is a major aquaculture species for the USA. The sustainable development of eastern oyster aquaculture depends upon the continued improvement of cultured stocks through advanced breeding technologies. The Eastern Oyster Breeding Consortium (EOBC) was formed to advance the genetics and breeding of the eastern oyster. To facilitate efficient genotyping needed for genomic studies and selection, the consortium developed two single-nucleotide polymorphism (SNP) arrays for the eastern oyster: one screening array with 566K SNPs and one breeders’ array with 66K SNPs. The 566K screening array was developed based on whole-genome resequencing data from 292 oysters from Atlantic and Gulf of Mexico populations; it contains 566,262 SNPs including 47K from protein-coding genes with a marker conversion rate of 48.34%. The 66K array was developed using best-performing SNPs from the screening array, which contained 65,893 oyster SNPs including 22,984 genic markers with a calling rate of 99.34%, a concordance rate of 99.81%, and a much-improved marker conversion rate of 92.04%. Null alleles attributable to large indels were found in 13.1% of the SNPs, suggesting that copy number variation is pervasive. Both arrays provided easy identification and separation of selected stocks from wild progenitor populations. The arrays contain 31 mitochondrial SNPs that allowed unambiguous identification of Gulf mitochondrial genotypes in some Atlantic populations. The arrays also contain 756 probes from 13 oyster and human pathogens for possible detection. Our results show that marker conversion rate is low in high polymorphism species and that the two-step process of array development can greatly improve array performance. The two arrays will advance genomic research and accelerate genetic improvement of the eastern oyster by delineating genetic architecture of production traits and enabling genomic selection. The arrays also may be used to monitor pedigree and inbreeding, identify selected stocks and their introgression into wild populations, and assess the success of oyster restoration.
Journal Article
Oyster (Crassostrea virginica) Aquaculture Shifts Sediment Nitrogen Processes toward Mineralization over Denitrification
Filter-feeding bivalves, like oysters, couple pelagic primary production with benthic microbial processes by consuming plankton from the water column and depositing unassimilated material on sediment. Conceptual models suggest that at low to moderate oyster densities, this deposition can stimulate benthic denitrification by providing denitrifying bacteria with organic carbon and nitrogen (N). While enhanced denitrification has been found at oyster reefs, data from oyster aquaculture are limited and equivocal. This study measured seasonal rates of denitrification, as well as dissimilatory nitrate reduction to ammonium (DNRA), and dissolved inorganic N fluxes at a rack and bag eastern oyster (Crassostrea virginica) aquaculture farm. Consistent with models, denitrification was enhanced within the farm, with an average annual increase of 350% compared to a reference site. However, absolute denitrification rates were low relative to other coastal systems, reaching a maximum of 19.2 m⁻² h⁻¹. Denitrification appeared to be nitrate (NO₃) limited, likely due to inhibited nitrification caused by sediment anoxia. Denitrification may also have been limited by competition for NO₃⁻ with DNRA, which accounted for an average of 76% of NO₃⁻ reduction. Consequently, direct release of ammonium (NH₄⁺) from mineralization to the water column was the most significant benthic N pathway, with seasonal rates exceeding 900 μmol m⁻² h⁻¹ within the farm. The enhanced N processes were spatially limited however, with significantly higher rates directly under oysters, compared to in between oyster racks. For commercial aquaculture farms like this, with moderate oyster densities (100-200 oysters m⁻²), denitrification may be enhanced, but nonetheless limited by biodeposition-induced sediment anoxia. The resulting shift in the sediment N balance toward processes that regenerate reactive N to the water column rather than remove N is an important consideration for water quality.
Journal Article
A Social-Ecological System Framework for Marine Aquaculture Research
Aquaculture has been responsible for an impressive growth in the global supply of seafood. As of 2016, more than half of all global seafood production comes from aquaculture. To meet future global seafood demands, there is need and opportunity to expand marine aquaculture production in ways that are both socially and ecologically sustainable. This requires integrating biophysical, social, and engineering sciences. Such interdisciplinary research is difficult due to the complexity and multi-scale aspects of marine aquaculture and inherent challenges researchers face working across disciplines. To this end, we developed a framework based on Elinor Ostrom’s social–ecological system framework (SESF) to guide interdisciplinary research on marine aquaculture. We first present the framework and the social–ecological system variables relevant to research on marine aquaculture and then illustrate one application of this framework to interdisciplinary research underway in Maine, the largest producer of marine aquaculture products in the United States. We use the framework to compare oyster aquaculture in two study regions, with a focus on factors influencing the social and biophysical carrying capacity. We conclude that the flexibility provided by the SESF is well suited to inform interdisciplinary research on marine aquaculture, especially comparative, cross-case analysis.
Journal Article
Sea Anemone Aiptasiomorpha minuta (Verrill, 1867) as a Possible Agent to Control Biofouling in Oyster Culture and the Optimal Conditions for Its Mass Rearing under Laboratory Conditions
The potential use of the sea anemone Aiptasiomorpha minuta as an agent for controlling biofouling on cultured oysters and the optimum culture conditions for its mass culture were evaluated. Field experiments showed that nineteen species (eight phyla), including two seaweed species, sponges, hydroids, bryozoans, mollusk/bivalve species, barnacles, and tunicates were found as biofouling assemblages on the oyster collectors. The ability of A. minuta to accumulate biomass on oyster collectors, thus, minimizing colonization by problem species; was also demonstrated to promote better oyster growth, condition index, and survival. Favorable mass culture conditions of A. minuta in laboratory trials were found at 28 °C, fed with Artemia salina (1000 individuals/day), and at 23 psu for the optimum temperatures, diet regimen, and salinity, respectively. These mass culture conditions could be useful for the purpose of producing enough biomass for attaching the sea anemones, A. minuta, to oyster collectors. The use of A. minuta could be a preventive strategy against biofouling that may be useful for oyster farmers; it is safe from the viewpoint of food hygiene, and is also environment-friendly.
Journal Article
Chesapeake Gold
The figure of an old man poling a skiff toward shore against the evening light engaged Susan Brait to learn about Chesapeake Bay, and it is that image which opens this her book on the oystermen of the Bay and the sapping of their traditional life, and even the bounty of the Bay itself, by the demands of American society.
With directness and poetic economy Brait takes the reader into the life of the Bay and into the complex relationships that affect oysters and those who make their living from them. Her account weaves easily from the daily work of oystermen to the natural forces that have shaped the Bay, from the experimental culture of oysters by marine biologists to the plans of businessmen who expect to grow and harvest the mollusks on privately owned reefs, from efforts to legislate control of the Bay and its resources to the upper reaches of the Susquehanna River where increasing pollution of the Bay originates from agricultural practices of the Amish and other farmers. These and other disparate elements are gracefully woven into a seamless web that represents the complex wholeness of the Bay itself.
Chesapeake Goldis a sensitive portrayal of people and their place, but it is also more. The oystermen and their efforts to maintain their traditional life become a figure for our society's struggle to find an ethic that will serve both man and the natural world that man is apart from and a part of.
eBook
Simulation of oyster ecological carrying capacity in Sanggou Bay in the ecosystem context
Aquaculture is a rapidly increasing industry, and managers in China are searching sustainable development in the context of much more intensive culture. Our study area focused on an embayment that exposed to suspended culture of oysters. Impact of oyster expansion was evaluated in the context of ecosystem which do not limits to the phytoplankton−oyster relationship but other interspecific relations by the use of food web model. Following recently proposed measures, the ecological carrying capacity (ECC) was defined as the maximum amount of oyster biomass that would not yet cause ecosystem function to depredate beyond their resilience capacity, i.e., not to cause any other group’s biomass to fall below 10% of its original biomass. The result suggests that an increase of oyster biomass caused negative impact on the ecosystem in terms of biomass of the most of functional groups and ecosystem indicators such as flow diversity and transfer efficiency. The ECC of oyster in suspended culture was 976 t km−2 (1.8 times of present biomass), and exceeding the levels will cause zooplanktivorous fish biomasses to fall below the 10% threshold. The ecosystem-based ECC assessment method in the present simulation dynamically predicted the impact of oyster development on other organisms in the environment to guide the sustainable development of bivalve culture in Sanggou Bay and provides an approach for the assessment of bivalve ECC in other parts of the world.
Journal Article
Nitrogen Uptake and Internal Recycling in Zostera marina Exposed to Oyster Farming: Eelgrass Potential as a Natural Biofilter
Oyster farming in estuaries and coastal lagoons frequently overlaps with the distribution of seagrass meadows, yet there are few studies on how this aquaculture practice affects seagrass physiology. We compared in situ nitrogen uptake and the productivity of Zostera marina shoots growing near off-bottom longlines and at a site not affected by oyster farming in San Quintín Bay, a coastal lagoon in Baja California, Mexico. We used benthic chambers to measure leaf NH₄⁺ uptake capacities by pulse labeling with ¹⁵NH₄⁺ and plant photosynthesis and respiration. The internal 15N resorption/recycling was measured in shoots 2 weeks after incubations. The natural isotopie composition of eelgrass tissues and vegetative descriptors were also examined. Plants growing at the oyster farming site showed a higher leaf NH₄⁺ uptake rate (33.1 mmol NH₄⁺ m⁻² day⁻¹) relative to those not exposed to oyster cultures (25.6 mmol NH₄⁺ m⁻² day⁻¹). We calculated that an eelgrass meadow of 15-16 ha (which represents only about 3-4 % of the subtidal eelgrass meadow cover in the western arm of the lagoon) can potentially incorporate the total amount of NH₄⁺ excreted by oysters (~5.2 × 10⁶ mmol NH₄⁺ day⁻¹). This highlights the potential of eelgrass to act as a natural biofilter for the NH₄⁺ produced by oyster farming. Shoots exposed to oysters were more efficient in re-utilizing the internal ¹⁵N into the growth of new leaf tissues or to translocate it to belowground tissues. Photosynthetic rates were greater in shoots exposed to oysters, which is consistent with higher NH₄⁺ uptake and less negative δ¹³C values. Vegetative production (shoot size, leaf growth) was also higher in these shoots. Aboveground/belowground biomass ratio was lower in eelgrass beds not directly influenced by oyster farms, likely related to the higher investment in belowground biomass to incorporate sedimentary nutrients.
Journal Article
The Influence of Oyster Farming on Sediment Bacterial Communities
Aquaculture currently provides half of all fish for human consumption, and this proportion is expected to in crease to meet the growing global demand for protein. As aquaculture, including oyster farming, expands, it is increas ingly important to understand effects on coastal ecosystems. The broad-scale ecological effects of oyster aquaculture are well documented; however, less is known regarding the influence of oyster aquaculture on sediment bacterial communities. To better understand this relationship, we compared three different oyster farming practices that varied in oyster biomass and proximity of oysters to the sediment. We used high throughput sequencing and quantitative polymerase chain reaction to examine the effect of oyster farming on sediment bacterial communities. We examined the entire bacterial community and looked specifically at bacteria that support essential estuarine ecosystem services (denitrifiers), as well as bacteria that can be detrimental to human health (members of the Vibrio genus). We found that oyster biomass increased Vibrio richness and sediment carbon content, which influenced bacterial community composition. When compared to reference sites, the overall abundance of bacteria was increased by the bottom planting method, but the associated increases indenitrifiers and Vibrio were not significant. We were unable to detect V. parahaemolyticus, V. vulnificus, or V. cholera, the three most common Vibrio pathogens, in any sample, suggesting that oyster farming did not enhance these potential human pathogens in sediments at the time of sampling. These results highlight how differences in oyster farming practice can affect sediment bacterial communities, and the ecosystem services they provide.
Journal Article
Meteorological and Water Quality Factors Associated with Microbial Diversity in Coastal Water from Intensified Oyster Production Areas of Thailand
Coastal pollution is of public health concern due to the possibility of bacterial contamination in aquaculture affecting health risk and seafood safety. This study determined the concentrations of total coliforms, fecal coliforms, E. coli, and V. parahaemolyticus and the presence of V. cholerae and Salmonella in water and measured water quality and meteorological factors from the major oyster cultivation areas in Thailand. The water samples (n = 363) were collected from Surat Thani (n = 60), Chanthaburi (n = 60), Trat (n = 60), Phetchaburi (n = 60), Chonburi (n = 63), and Phang Nga (n = 60) from February 2021 to January 2022. The prevalence of total coliforms (96.7%), fecal coliforms (60.6%), E. coli (22.9%), along with the prevalence of Salmonella (2.5%), Vibrio parahaemolyticus (74.9%), and V. cholerae (11.3%) were determined. Common Salmonella serovars were Othmarschen and Lamberhurst. The concentration of E. coli was significantly associated with dissolved oxygen and precipitation (p < 0.0001). Therefore, continuing microbiological monitoring and surveillance of water for coastal aquaculture is important to produce safe aquatic products. Furthermore, raising awareness of coastal pollution and seafood safety will help enhance sustainable coastal fisheries in Thailand.
Journal Article