Oyster Culture Research Articles

Comprehensive review on oyster mushroom species (Agaricomycetes): Morphology, nutrition, cultivation and future aspects

Huge volumes of organic matter are produced on earth via photosynthesis and their disposal is a serious threat to the environment and public health all over the world. Nevertheless, these agricultural wastes possess a chemical composition conducive to mushroom cultivation. Lignocellulosic wastes, comprising cellulose, hemicellulose and lignin, offer vital nutrients for mushroom growth. Oyster mushrooms are well known for their unique ability to degrade lignocellulosic materials, making them valuable contributors to the process of organic waste decomposition and nutrient cycling in ecosystems. Employing agricultural by-products as a substrate for mushroom cultivation presents a sustainable approach to waste reduction and the production of nutritionally enriched food. Cultivating oyster mushrooms, presents an economically feasible and environment friendly method of transforming waste materials into highly nutritious food. These edible mushrooms are widely grown worldwide, comprising around 27 percent of the total global production. Oyster cultivation has rapidly increased in Asia due to its low production technology, easy availability of substrates, temperature tolerance and high yield capacity. Oyster mushrooms are sought after as a functional food due to their appealing taste, aroma, flavor, nutritional benefits and medicinal properties. They contain high levels of protein, fiber, vitamins B complex, C and D2, as well as minerals like potassium, phosphorus, selenium, zinc and essential amino acids. These mushrooms are versatile, as they thrive in both tropical and temperate regions without requiring complex controlled environmental conditions for growth. This review article provides insights into the cultivation aspects of important oyster species including a novel species called Hypsizygus ulmarius. Oyster mushroom cultivation is rapidly growing in developing countries, where it can contribute to food security for the world's growing population, which is expected to reach 9.7 billion by 2050.

Geographical distribution and ecological niche dynamics of Crassostrea sikamea (Amemiya, 1928) in China's coastal regions under climate change

Global climate change drives species redistribution, threatening biodiversity and ecosystem heterogeneity. The Kumamoto oyster, Crassostrea sikamea (Amemiya, 1928), one of the most promising aquaculture species because of its delayed reproductive timing, was once prevalent in southern China. In this study, an ensemble species distribution model was employed to analyze the distribution range shift and ecological niche dynamics of C. sikamea along China's coastline under the current and future climate scenarios (RCP 2.6–8.5 covering 2050 s and 2100 s). The model results indicated that the current habitat distribution for C. sikamea consists of a continuous stretch extending from the coastlines of Hainan Province to the northern shores of Jiangsu Province. By the 2050 s, the distribution range will stabilize at its southern end along the coast of Hainan Province, while expanding northward to cover the coastal areas of Shandong Province, showing a more dramatic trend of contraction in the south and invasion in the north by the 2100 s. In RCP8.5, the southern end retracts to the coasts of Guangdong, whereas the northern end covers all of China's coastal areas north of 34°N. C. sikamea can maintain relatively stable ecological niche characteristics, while it may occupy different ecological niche spaces under future climate conditions. Significant niche expansion will occur in lower temperature. We concluded C. sikamea habitats are susceptible to climate change. The rapid northward expansion of C. sikamea may open new possibilities for oyster farming in China, but it will also have important consequences for the ecological balance and biodiversity of receiving areas. It's imperative that we closely examine and strategize to address these repercussions for a win-win situation.

Growth of Oyster (Crassostrea virginica) Larvae in Small-Scale Systems Using an Algae Concentrate Food Source

Replicated studies are advantageous for optimizing larval rearing of the Eastern oyster (Crassostrea virginica) and increasing the availability of high-quality seed for the continued expansion of the U.S. oyster aquaculture industry. Although small-scale systems using live algal feeds have been used successfully, rearing larvae on algae concentrate presents additional challenges. To determine the feasibility of rearing oyster larvae in small-scale systems using algae concentrate, oyster larvae were raised for 2 weeks in replicate control (1,000 L) and microcosm (17 L) tanks. Five aeration strategies were tested in the microcosms in two separate trials. Results of this study indicate similar survival in small systems compared to controls through the appearance of eyed larvae. Accumulated algae and pink biofilm formation in microcosms using polyvinyl chloride (PVC) airlifts suggest that this aeration strategy is undesirable. One- and 5-mL air injectors maintained higher overnight oxygen levels than controls. The recovery of more eyed larvae after 14 dpf in control systems may be the result of significant temperature fluctuations in microcosms. Overall, this study demonstrates that algae concentrate can be used to rear oyster larvae in small-scale systems, providing a live feed alternative that saves space and labor in replicated studies.

Unveiling CRESS DNA Virus Diversity in Oysters by Virome.

Oysters that filter feed can accumulate numerous pathogens, including viruses, which can serve as a valuable viral repository. As oyster farming becomes more prevalent, concerns are mounting about diseases that can harm both cultivated and wild oysters. Unfortunately, there is a lack of research on the viruses and other factors that can cause illness in shellfish. This means that it is harder to find ways to prevent these diseases and protect the oysters. This is part of a previously started project, the Dataset of Oyster Virome, in which we further study 30 almost complete genomes of oyster-associated CRESS DNA viruses. The replication-associated proteins and capsid proteins found in CRESS DNA viruses display varying evolutionary rates and frequently undergo recombination. Additionally, some CRESS DNA viruses have the capability for cross-species transmission. A plethora of unclassified CRESS DNA viruses are detectable in transcriptome libraries, exhibiting higher levels of transcriptional activity than those found in metagenome libraries. The study significantly enhances our understanding of the diversity of oyster-associated CRESS DNA viruses, emphasizing the widespread presence of CRESS DNA viruses in the natural environment and the substantial portion of CRESS DNA viruses that remain unidentified. This study's findings provide a basis for further research on the biological and ecological roles of viruses in oysters and their environment.

Effects of intensive oyster farming on nitrogen speciation in surface sediments from a typical subtropical mariculture bay

The spatial-temporal distributions of various nitrogen (N) species in surface sediments were examined in a typical subtropical mariculture bay (Maowei Sea) in the northern Beibu Gulf to assess the impact of intensive oyster culture activities on sedimentary N speciation. The results indicated that the mean contents of total nitrogen (TN), extractable (labile) nitrogen (LN) and residual nitrogen (RN) in the surface sediments were 33.3 ± 15.5 μmol g−1, 13.8 ± 1.3 μmol g−1 and 19.5 ± 15.0 μmol g−1, respectively, which lacked significant seasonal variability (P > 0.05). Four forms of LN, namely ion extractable form (IEF-N), weak acid extractable form (WAEF-N), strong alkali extractable form (SAEF-N) and strong oxidant extractable form (SOEF-N) were identified based on sequential extraction. SOEF-N was the dominant form of LN, accounting for 67.8 ± 2.5 % and 63.7 ± 5.9 % in summer and winter, respectively. Spatially, the contents of sedimentary TN, LN, RN, WAEF-N and SOEF-N in intensive mariculture areas (IMA) were significantly higher than those in non-intensive mariculture areas (NIMA) during summer (P < 0.05). Stable nitrogen isotope (δ15N) mixing model revealed that shellfish biodeposition was the predominant source of sedimentary TN in IMA with a contribution of 67.8 ± 23.0 %, approximately 5.4 times that of NIMA (12.6 ± 3.3 %). Significant positive correlations (P < 0.05) were observed between most forms of N species (WAEF-N, SOEF-N, LN and RN) and shellfish-biodeposited N in the surface sediments during summer, indicating that intensive oyster farming greatly enhanced sedimentary TN accumulation.

Spatial and temporal variability in infestation of Oregon oyster farms by shell-boring polychaetes

Shell-boring polychaetes burrow into the shells of cultivated and wild molluscs, leading to the formation of unsightly blisters that fill with mud, detritus, and fecal material. Infestation of cultivated oysters poses economic risks for the Pacific Northwest’s shellfish mariculture industry because the blisters reduce the aesthetic quality and market appeal of oysters sold on the half-shell market. To help Oregon’s multimillion-dollar mariculture industry develop resilience against this emerging biosecurity threat, we quantified seasonal variability and spatial differences in the infestation of Pacific oysters (Crassostrea gigas) by shell-boring polychaetes, and assessed whether prevalence varied among grow-out methods, seasons, and host traits (shell height and tissue mass). In 2019–2021, we obtained 829 Pacific oysters from seven commercial shellfish farms spanning the Oregon coast (Tillamook Bay, Netarts Bay, Yaquina Bay, and Coos Bay), and observed a mean statewide infestation rate of 11–31% over four sampling seasons. We observed the highest prevalence of infestation by shell-boring polychaetes (72%) in Netarts Bay. Oysters cultivated off-bottom exhibited lower prevalence of infestation than oysters grown on-bottom. Our study also revealed a significant effect of seasonality, with higher rates of infestation during winter. Oyster shell height and tissue mass were not significantly associated with the prevalence of infestation. Our observations identify an infestation hotspot in Netarts Bay, and suggest that off-bottom culture may help reduce infestation rates, mitigating damage caused by shell-boring polychaetes in Oregon bays and estuaries.

Evaluation of Mud Worm (Polydora spp.) Infestation in Cupped (Crassostrea gigas) and Flat Oyster (Ostrea edulis) Broodstocks: Comparison between Magnetic Resonance Imaging and Computed Tomography.

The Polichete worms of the genus Polydora are considered very destructive for oysters, excavating channels in their shell and inducing oysters to create mud blisters in response to the irritation, interfering with their physiology and ethology. The parasite also causes important economic damage for oyster farmers, as products with a high degree of infestation cannot be commercialized. The present study aims to evaluate whether two non-invasive advanced diagnostic techniques, computed tomography scans (CT) and magnetic resonance imaging (MRI), are suitable to show the alterations induced by this parasite on live Crassostrea gigas and Ostrea edulis oyster broodstocks. A CT scan is also able to identify small lesions in the shell during the first stage of infection. MRI allows for the visualization of the advanced status of the lesions when blisters occupy the inner surface of the shell and can impact the health status and the economic value of the mollusk. Both techniques resulted in satisfactory spatial resolution, and no motion artifacts were reported, thus enabling the authors to faithfully visualize in vivo the damage caused by the parasite.

Tidal asymmetry and mud transport in Oualidia Lagoon: Actual conditions in 2012 and rehabilitation scenarios

Oyster aquaculture in Oualidia Lagoon, Morocco, has suffered from poor water quality and water confinement in its upstream region. Tidal asymmetry (TA) has been suggested as a possible cause, and a sediment trap was dredged in 2011 to mitigate this condition. This study addresses TA in the lagoon using field measurements and numerical modeling in the presence of the sediment trap. Results indicate that the lagoon is flood-dominated mostly in its upstream end, where frictional forces exceed inertia accelerations during the tidal cycle and fine sediments settle on the tidal flats and inside the sediment trap. However, this study shows that a large mass of suspended sediments is exported to the ocean, which is contrary to expectations in flood-dominated lagoons. Defining the sediment trap as the rehabilitation scenario S1, the impacts of three additional scenarios on TA are examined. These are scenario S2 (dredging the upstream section of the main channel), scenario S3 (dredging the channels surrounding the flood delta near the inlets), and scenario S4 (raising the ocean level by 0.5 m following climate change predictions). Results show that none of these scenarios modify the tidal flood dominance in the lagoon, although scenarios S2 and S4 decrease its intensity in the upstream region. Nevertheless, all scenarios still contribute to a significant export of sediments to the ocean. This suggests that lagoon management activities should not rely on tidal asymmetry analyses that normally predict upstream sediment transport in flood-dominated lagoons.

Stable isotopes reveal intertidal fish and crabs use bivalve farms as foraging habitat in Puget Sound, Washington

Bivalves such as oysters and clams have been farmed in intertidal zones across the Puget Sound region of the Salish Sea for thousands of years. The variety of gear types used on bivalve farms creates complex vertical structure and attachment points for aquatic epiphytes and invertebrates which increases habitat structural complexity, but may alter eelgrass cover in areas where bivalve farms and eelgrass meadows overlap. Eelgrass meadows are highly productive and ecologically foundational nearshore habitats that provide valuable ecosystem services including the provision of nursery, refuge, and foraging habitat. Aquaculture has been a key feature of the environment in the Puget Sound for millennia, however, little is known about how well aquaculture practices are integrated into the system, and what services they provide to mobile species assemblages relative to unfarmed eelgrass meadows. We used stable isotope mixing models to estimate, for several species of nearshore fish and crab in two areas of North Puget Sound, Washington, the percent diet originating from either a natural bottom habitat (eelgrass meadows), farm habitat (oyster farms), or pelagic planktonic sources. Our results indicate that several species of nearshore fish such as surf perch and staghorn sculpin derive a significant proportion of their diets from farm areas, while crabs derive most of their diets from eelgrass habitat, and stickleback derive a significant proportion of their diets from planktonic sources. The results indicate that foraging habitat uses are species specific, and that several species that spatially overlap bivalve farms obtained a large percentage of their diets from adjacent bivalve farm habitat.

Optimizing the post-harvest salting of cultured oysters (Crassostrea virginica) using a recirculating wet storage system by monitoring adductor hemolymph osmolality

The oyster aquaculture industry is steadily growing in the United States, principally driven by the rise of small farms. With an increasingly crowded marketplace, farmers are searching for methods to diversify their crops and remain competitive. Enhancing oyster liquor in wet storage while preserving the water's signature flavor, or ‘merroir,’ is one way to create a new product line and differentiate crops, especially with oysters grown in low-salinity environments. Previously, growers have attempted to increase the salinity of their product by ‘finishing’ their oysters in a saltier water body; however, mass mortality may accompany such a transfer. Therefore, implementing a wet storage system may be a useful intermediary step to reduce crop mortality prior to ‘finishing’ oysters in alternative waters. This project sought to understand how to effectively use recirculating aquaculture systems (RAS) as wet storage to expose harvested oysters to a chosen salinity and temperature to function as a modified wet storage system. Additionally, this experiment describes the effects of both short-term and long-term salinity and temperature stress on the survival, condition index, and shelf life of adult oysters. The shelf life and rate of osmoconformity of low-salinity adult oysters depend on ambient temperature and acute changes in salinity. While increasing ambient temperature improves the rate of hemolymph osmoconformity, we observed high mortality above 25 °C. Additionally, the shelf life of oysters was negatively affected by the length of exposure time to higher salinity and increasing temperature. These data can guide oyster growers in low-salinity regions who wish to diversify their product using recirculating tanks or better understand the potential risks associated with transferring cultured oysters across water bodies of varying salinity.

Relationships between high temperatures and Pacific Oyster disease and mortality in southeast Tasmania, Australia

Warm ocean temperature extremes, including marine heatwaves, have profound impacts on natural marine systems and aquaculture industries across the globe. In Tasmania, Australia, one aquaculture industry that has been significantly impacted by warm temperatures is Pacific Oyster (Magallana gigas, previously named Crassostrea gigas) farming, due to recurring outbreaks of the virus Ostreid herpesvirus 1. Such viral outbreaks are understood to be driven by high seawater temperatures, but the temperature threshold or duration for triggering disease and mortalities remain unclear. This study investigates the relationship between in-situ farm temperatures and oyster disease and mortality on the southeast coast of Tasmania, Australia using daily observations from three oyster growing areas (Pipe Clay Lagoon, Upper Pittwater, and Lower Pittwater) over three seasons. It is found that a 12-day averaged daily mean temperature is an excellent measure of the occurrence of high mortality. Specifically, a 21-day mean of 23.7 °C resulted in a 70% likelihood of high mortality, which is defined here as oyster losses of >15%. On the other hand, for lower levels of disease and mortality, a 12-day average of daily mean temperature gave the strongest relationship. A 12-day mean of 19.7 °C led to 70% probability of some disease and low mortality. The analysis also found in-situ farm temperature generally correlates well with remotely sourced temperature observations, indicating their potential usability for operational management. This study demonstrates a statistical risk analysis framework for the oyster farming industry, helping to improve the understanding of the detrimental impact of high temperatures on Pacific Oysters.

Predicting restoration and aquaculture potential of eastern oysters through an eco-physiological mechanistic model

A simple, non-negotiable truth of ensuring success in the restoration of ecological engineers (EE) and the functions they support is the need for the focal species to survive, grow and reproduce. Using mechanistic modeling, such as a dynamic energy budget (DEB), to map an EE's fundamental niche supports restoration and management predictive of EE resilience under current and future conditions. One EE, the eastern oyster, Crassostrea virginica, provides critical estuarine habitat and supports a valuable fishery across the northern Gulf of Mexico. Recent declines in oyster populations in this region from anthropogenic activities and extreme events have led to significant efforts to restore wild, self-sustaining broodstock reefs, and develop off-bottom aquaculture. To explore potential outcomes for oyster restoration and aquaculture development, we used an individual bioenergetic model based on DEB theory to derive an aquaculture index, based on survival and time to market size, and a restoration index, based on survival and reproductive output. The model was run across six major Texas and Louisiana estuaries under current (2014–2020) and future (2041–2050) projected environmental conditions. Aquaculture scores using daily averaged current conditions reproduce an observed gradient of oyster growth success increasing from the upper estuary to lower estuary (Texas) or offshore areas (Louisiana), with lower variation occurring in Texas estuaries. Restoration scores under daily averaged current conditions showed similar trends with more variability than the aquaculture index due to spawning potential, which is important for reef sustainability. In general, Louisiana estuaries showed higher growth rates and reproduction than Texas estuaries, but due to the higher variability and more frequent extremes in salinity and temperature, Louisiana estuaries were more likely to experience mortal conditions in any given year, as compared to Texas estuaries. Comparison between current and future conditions indicated that oyster aquaculture and restoration potential in presently occupied areas might decrease in the future; however, the spatial resolution of currently available climate model outputs within coastal and estuarine areas limits planning information. Addressing this gap represents a necessary improvement to better evaluate the physiological response of EE to future conditions, especially since most aquaculture and restoration developments are likely to occur close to the coastline. Finally, this work demonstrates the potential of mechanistic modeling to inform future planning under environmental conditions not currently within the realized niche of EE.

Advancing The Blue Economy Through Sustainable Mariculture: The Prospect of Pearl Oyster and Sponge Cultivation in St. Vincent and The Grenadines

The Blue Economy is estimated to be worth over USD 2.5 trillion annually, or almost 3% of the world’s GDP in 2020. St. Vincent and the Grenadines (SVG) in the Caribbean region has a vast and rich marine space that is underutilized. This study aimed to explore the feasibility of pearl oyster and sponge farming to advance the country’s Blue Economy through sustainable mariculture. A qualitative approach was applied, using a literature review and thematic analysis of data gathered through semi—structured interviews and focus group discussions with relevant stakeholders. Among several species evaluated, the result of the study revealed that the Pinctada imbricata oyster species and Hippospongia lachne sponge species are the most suitable for cultivation in SVG coastal waters, specifically in the Ashton Lagoon of Union Island. The study concluded that while there is strong support from the stakeholders in SVG for pearl oyster and sponge farming in the country, challenges still exist. Nevertheless, it has been found that by learning and adopting the strategies of the leading Small Island Developing States (SIDS) in the Blue Economy development combined with the critical enablers such as meticulous planning, stakeholder collaboration, establishment of legal frameworks, and ecosystem—based management, pearl oyster and sponge mariculture in the identified location in SVG could potentially aid the expansion of the country’s Blue Economy.

Growing a Domestic Workforce for Oyster Aquaculture Through Operation of a Demonstration Oyster Farm in Maryland

The oyster aquaculture industry presents employment opportunities for a range of skill sets, education levels, and backgrounds (Engle, 2021), including but not limited to farm owners/operators, farm workers, food safety specialists, engineers, regulators, and researchers. Labor challenges pose an obstacle to growth, driven in part by lack of awareness of job opportunities in domestic aquaculture and lack of a trained workforce prepared to drive the industry forward (Sandolo, 2021).

Producing Supersaturated Dissolved Oxygen Seawater by Photosynthesis of Ulva sp. and Its Applications

In order to create new value in biomass production using sterile Ulva with high production efficiency, we selected sterile Ulva with high culture stability from the coast of Imari City in Japan and investigated the conditions for generating high concentrations of dissolved oxygen through photosynthesis using the sterile Ulva. In the cultivation of sterile Ulva, we investigated the conditions for generating high concentrations of dissolved oxygen (DO) by controlling conditions such as aeration, NO3‐N concentration, and population density. As a result, we found that under the cultivation control conditions we found, DO reached about 3.8 times the saturation concentration after 3 h. It was found that this high level of DO can be maintained if the supersaturated DO seawater obtained here is properly sealed. Seawater containing high levels of DO is essential for the cultivation of oysters and shellfish, which also prefer a growth temperature of 20°C−25°C. Therefore, from the perspective of creating new value in biomass production, we developed a new system for simultaneously cultivating sterile Ulva and cultivating oysters.

Oyster aquaculture enhances sediment microbial diversity: insights from a multi-omics study

Oyster aquaculture enhances sediment microbial diversity: insights from a multi-omics study

Diversifying Louisiana’s Oyster Industry Through Alternative Oyster Culture

At the behest of the state and industry, Louisiana Sea Grant (LSG) facilitated the expansion of alternative oyster culture (AOC) across Louisiana’s coastal zone through a $3 million, three-year aquaculture grant program launched in 2021.

Inovasi desain keramba untuk budidaya tiram dalam meningkatkan ekonomi masyarakat pesisir di Gampong Cot Seurani, Kabupaten Aceh Utara (Innovation of cage design for oyster cultivation on improving the economy of coastal communities in Cot Seurani Village, Aceh Utara District)

Cot Seurani Village is one of the coastal villages in Muara Batu District, North Aceh Regency which has fisheries and marine potential that can be used as oyster cultivation land. The people in Cot Seurani Village predominantly work as fishermen, the potential of existing oysters has not been utilized optimally, they still collect them directly from nature, such as on rocks at TPI and its surroundings. The aim of this service activity is to introduce, socialize and directly practice the innovation of oyster cages which can be used as oyster cultivation business land in Cot Seurani Village, North Aceh in order to encourage oyster farmers to open oyster cultivation businesses independently and in a measurable manner using economical materials. The stages of this activity include program planning, preparation, socialization on making oyster cages, lowering oyster cages into the sea and monitoring and evaluating to publishing the results of the service in print media and scientific journals, as well as making reports on the results of the service. The final result, in the form of samples of oyster cage products that have been lowered into the sea, can be used by oyster farmers as an environmentally friendly oyster cultivation area to facilitate the production process and improve the welfare of oyster farmers in Cot Seurani Village.

Taxon-Specific Habitat and Tidal use by Birds in an Oyster Culture Estuary

Taxon-Specific Habitat and Tidal use by Birds in an Oyster Culture Estuary

Pathology associated with summer oyster mortality in North Carolina

Expansion of oyster aquaculture industries throughout the southeastern United States has been met with recurring, often catastrophic mortality events, limiting capacity for industry growth. Numerous etiologies have been proposed, including regional extensions of enigmatic mortality episodes that have been observed in triploid oysters in Chesapeake Bay as well as the mid-Atlantic and Gulf of Mexico coasts. To better understand associated pathology and begin to address etiology, we conducted a longitudinal histological survey at a commercial oyster farm in North Carolina that experiences recurring mortality. Our survey was timed with dramatic mortality experienced across North Carolina oyster farms, with farmer-reported mortalities exceeding 90% of near market-sized oysters. Surveyed oysters presented with persistent digestive diverticula pathology in the weeks leading up to and through the mortality event and suggest that mortality was ultimately a result of nutritional deprivation. These observations are inconsistent with pathology associated with recent observations of triploid associated mortality in eastern oysters, however similar diverticula pathology has been observed with summer mortality in Pacific oysters. Expanded research into comparative etiology throughout impacted regions and across oyster species will help address oyster mortality events worldwide. Further efforts for eastern oysters are now being concentrated toward understanding variation in resistance to recurring mortality events across commercially available oyster lines.