Aquaculture Fish Ponds Research Articles

Composition and bioaccessibility of elements in green seaweeds from fish pond aquaculture

The elemental composition of five species of green seaweeds (Chaetomorpha linum, Rhizoclonium riparium, Ulva intestinalis, Ulva lactuca, Ulva prolifera) grown in fish pond aquaculture systems were studied. The elemental bioaccessibility in these species was also investigated through the application of an innovative in vitro digestive model of the human gastrointestinal tract.It was observed that R. riparium had the highest levels of Mn, Sr, Cd, Sn, and I and that U. lactuca had the highest Ni and Cu concentrations. The daily amounts of dried green seaweed required for achieving specific dietary intakes were calculated, namely: 7g of dried U. lactuca (for meeting Cu Recommended Daily Allowance, RDA); 173g of dried U. lactuca (Zn RDA); 78g of dried C. linum (Se RDA); 41g of dried C. linum (Mo RDA); and 0.5g of dried R. riparium (I Dietary Reference Intake, DRI). Concerning elemental bioaccessibility, Mn and Cu had the highest values, always above 50%, I values were in the lower range, between 14 and 31%. The elemental bioaccessibility range of R. riparium (31–100%) was higher than the ranges for other species, particularly C. linum (0–56%). The bioaccessibility results entailed higher quantities of dried seaweed for reaching dietary intakes: 10g of dried U. lactuca (Cu RDA); 290g of dried R. riparium (Zn RDA); and 2g of dried R. riparium (I DRI). Accordingly, R. riparium is a very rich I source. This study showed the importance of taking into account bioaccessibility results in estimating dietary intakes.

Large-scale climatic effects on traditional Hawaiian fishpond aquaculture.

Aquaculture accounts for almost one-half of global fish consumption. Understanding the regional impact of climate fluctuations on aquaculture production thus is critical for the sustainability of this crucial food resource. The objective of this work was to understand the role of climate fluctuations and climate change in subtropical coastal estuarine environments within the context of aquaculture practices in Heʻeia Fishpond, Oʻahu Island, Hawaiʻi. To the best of our knowledge, this was the first study of climate effects on traditional aquaculture systems in the Hawaiian Islands. Data from adjacent weather stations were analyzed together with in situ water quality instrument deployments spanning a 12-year period (November 2004 –November 2016). We found correlations between two periods with extremely high fish mortality at Heʻeia Fishpond (May and October 2009) and slackening trade winds in the week preceding each mortality event, as well as surface water temperatures elevated 2–3°C higher than the background periods (March-December 2009). We posit that the lack of trade wind-driven surface water mixing enhanced surface heating and stratification of the water column, leading to hypoxic conditions and stress on fish populations, which had limited ability to move within net pen enclosures. Elevated water temperature and interruption of trade winds previously have been linked to the onset of El Niño in Hawaiʻi. Our results provide empirical evidence regarding El Niño effects on the coastal ocean, which can inform resource management efforts about potential impact of climate variation on aquaculture production. Finally, we provide recommendations for reducing the impact of warming events on fishponds, as these events are predicted to increase in magnitude and frequency as a consequence of global warming.

Fatty acid profiles of the main lipid classes of green seaweeds from fish pond aquaculture.

The lipid composition of five species of green seaweeds (Chaetomorpha linum, Rhizoclonium riparium, Ulva intestinalis, Ulva lactuca, and Ulva prolifera) grown in fish pond aquaculture systems was studied. In particular, the overall fatty acid (FA) profile and the FA profile of each main lipid class found in these seaweed species were thoroughly analyzed. It was found that every seaweed had a specific FA profile, whose specificities were rendered more obvious with the study of the FA profile per lipid class. However, between U. lactuca and U. intestinalis, there were only minor differences. Nonetheless, it was possible to identify significant differences between the palmitic acid content in the phospholipid (PL) and glycolipid (GL) classes of each seaweed. A clear distinction between the FA profiles of R. riparium and C. linum, which belong to the Cladophorales order, and those of Ulva genus, Ulvales order, was also determined. Moreover, there were also differences among lipid classes, yielding large contrasts between PLs + GLs and triacylglycerols (TAGs) as well as between monoacylglycerols (MAGs) and free fatty acids (FFAs). This study also found evidence supporting the location of particular FAs in specific TAG positions. FA profiles have the potential to be used as a chemotaxonomic tool in green seaweeds, providing a simple method to check authenticity of seaweed used as food.

Malachite-green-removing properties of a bacterial strain isolated from fish ponds in Thailand

Malachite green (MG) has been focused on as a biotreatment target and its biological properties have also been an issue in food fish aquaculture. An MG-removing bacterium was isolated from aquaculture fish pond sediment samples in Thailand. The isolate, strain T-5-2, is a Gram-negative, aerobic rod-shaped bacterium, and has been identified as a member of the Pseudomonas putida group. Proton nuclear magnetic resonance spectroscopy (1H-NMR) analysis of a broth culture medium containing MG showed that the concentration of MG decreased markedly and that other molecules, including leucomalachite green (LMG), were generated. Moreover, liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis showed that the MG concentration in the broth culture medium continuously decreased. This analysis also demonstrated that the concentration of LMG initially increased and then gradually decreased. Furthermore, gas chromatography–mass spectrometry (GC–MS) analysis showed 4-(dimethylamino)benzophenone (4DABP) as a degradation component of MG, which was confirmed by 1H-NMR and LC–MS/MS analysis. These findings suggest that this bacterial strain can remove MG in broth culture and degrade it to certain metabolites, including LMG and 4DABP. This study is the first detailed evaluation by the combination of LC–MS/MS, GC–MS, and 1H-NMR analyses of an MG-removing bacterium isolated from Thai aquaculture fish ponds.

Economic feasibility of producing oysters using a small-scale Hawaiian fishpond model

Traditional fishpond aquaculture in Hawai‘i has declined since global trade provided access to cheaper, imported food. Farming non-native species like the Pacific oyster may prove more profitable than traditional species, and may help maintain the practice of fishpond aquaculture. Little literature exists on the economics of Hawai‘i’s oyster culture or the unique practices involved in fishpond-based production. Based on information supplied by a currently operating farm, we developed an enterprise budget for a model farm in order to 1) assess profitability, 2) determine sensitive input parameters, and 3) use stochastic modeling to determine the likelihood of different economic outcomes. The budget returned a marginally negative profit, with the bulk of operating costs from labor. Decision reversal analysis showed the model farm can be profitable with an increase in market price from US $1.25 to US $1.35 per oyster or a decrease in mortality rate from 50% to 45.9% – both are within reasonable reach in the near future.

Aquatic plants for bioremediation in red hybrid tilapia (Oreochromis niloticus × Oreochromis mossambicus) recirculating aquaculture

This study investigated using aquatic flowering plants (Canna generalis L., Typha angustifolia L., Echinodorus cordifolius L. and Cyperus involucratus [Rottb].) for nitrogenous waste removal from tropical aquaculture fishponds. Two plants which had higher removal efficiency (Canna generalis L. and Echinodorus cordifolius L.) were selected for further study in different light intensities and substrates. The effects of different light intensities were significantly different (P 0.05), but higher planting densities were counterproductive in terms of both water quality and fish survival. Flow rates of >100 % day−1 were needed for efficient nitrogenous waste removal. Red hybrid tilapia in the optimal setup (50 fish m−2, 12 plants m−2, 100 % water turnover per day) had weight gains of 629 %, a survival rate of 82.7 %, a feed conversion ratio of 0.72, and a specific growth rate of 4.7 % day−1 over a 6-week experimental period.

Sustainability of fish pond culture in rural farming systems of Central and Western Cameroon

In Sub-Saharan Africa, fish ponds are often an integral part of farming systems but have suffered from a lack of viability and sustainability. The present study aims to understand the strategies used by fish farmers to overcome economic and environmental constraints. In 2008 and 2009, fish farmers were surveyed in Central and Western Cameroon, and the fish production systems were classified by cluster analysis. Four broad types were identified according to the complexity of household operations. The development of extensive systems (large-scale and low-input) in rural areas of central Cameroon is induced mainly by abundant available land. For semi-intensive systems in both regions (small-scale and high-input in the Western Region, large-scale and high-input in peri-urban areas of the Central Region), horizontal integration is not sufficient to make fish production profitable and sustainable. More intensive fish farms tend towards vertical integration, in which farmers establish close links with input suppliers. Main causes of low productivity of semi-intensive systems (1–2 t/ha/yr) are both lack of knowledge of fish farming principles by farmers and lack of technical improvement by extension agents and researchers which need to consider the local complexity of farming systems to develop and intensify fish production. The adaptation of development strategies to socio-economic and environmental contexts is a necessity to hope for an increase in fish pond aquaculture production in Africa.

Comparison of live and dead molluscan assemblages suggests recent human-driven decline in benthic diversity in Phetchaburi (NW Gulf of Thailand)

Dead and live molluscan assemblages from the coastal area of Phetchaburi (NW Gulf of Thailand) were compared by means of multivariate analysis.Seven thanatofacies were recognized, thriving in the area after the 1960s. Five of them, scattered along the tidal flat, represent oligotypic intertidal biotopes linked to a variety of environmental factors; the remaining two mirror high-diversity infralittoral associations.Conversely, only two poor, ill-defined biofacies thrive at present between the intertidal and the shallow infralittoral zones, somewhat resembling two of the thanatofacies.Diversity indexes reveal a dramatic biodiversity decline occurred from the 1960s onwards, far beyond the effects of time-averaging and accumulation. The responsibility for this reduction is largely attributable to the high impact of human activities, such as the intensive sea bottom trawling, the wastewaters from aquaculture (shrimp and fish ponds) and dense coastal villages, and, at a minor extent, the digging of edible molluscs from the tidal flat.

PRESENCE AND ABUNDANCE OF CYANOBACTERIA IN SELECTED AQUACULTURE PONDS IN PERAK, MALAYSIA AND THE RELATIONSHIPS WITH SELECTED PHYSICOCHEMICAL PARAMETERS OF WATER

The presence of cyanobacteria in aquaculture ponds can disrupt the water quality. This study was conducted to determine the abundance of cyanobacteria in selected aquaculture systems in Perak, Malaysia. This study also aimed to identify the relationships between cyanobacterial biomass with physicochemical properties of water. In this study, a total of 40 aquaculture fish ponds were sampled between December 2013 to March 2014 from 10 locations in Perak, Malaysia. The results revealed that cyanobacteria were present in all of the sampled aquaculture ponds. Among all, 75% of the sampled ponds contained chlorophyll-a exceeded 50 µg chl-a L-1 and the highest chlorophyll-a concentration was recorded at 436 µg chl-a L-1. This indicates that cyanobacteria are present in abundance in aquaculture water and could pose health risk to human through aquaculture fish consumption. Pearson’s correlation analysis suggests that cyanobacterial biomass was significantly correlated to temperature, DO and pH. However, there was no correlation detected among nutrients with cyanobacterial concentration in water column. Regular monitoring of temperature, DO and pH are crucial for an early detection of cyanobacterial occurrence in aquaculture industry in order to avoid economic losses, as well as adverse health impact to consumer.

Effect of Fish Transportation on immunological response and Bacterial Diseases in Anabas Testudineus Fish

This study was conducted to determine the condition of immunological response of and the presence of bacterial diseases in Anabas Testudineus fish was transported from pond culture towards Segiri Market. Transport system carried out by the fishmonger supposed to influence the health conditions of fish as well as the presence of bacteria on the fish's body. The sample was 30 fish from Muara Kaman pond and Markets Segiri as a fish marketing. Some parameters were observed among others: changes in swimming behavior, pathology anatomy organs, aemotology and inventory of bacterial diseases. The results showed that the samples of fish from the pond aquaculture generally have normal conditions of organ anatomy, symptom behavior swim also normally, otherwise fish from marketed in the Market Segiri, as much as 60% of fish have abnormal behavior of swimming, 73% have pathology on external anatomy and 53% fish have abnormalities in organs. Results of the isolation and identification of bacterial disease found that there are 5 types of bacteria Aeromonas, Pseudomonas, Staphyllococcus, Streptococcus and Basillus, and only bacteria Staphyllococcus and Basillus not found in fish pond aquaculture origin. The health condition of the fish pond aquaculture origin betook better, judging from the hemoglobin, hematocrit, total leukocyte and total erythrocyte that is within the normal range. While the blood picture fish from Segiri market is generally higher in all parameters that indicate health problems. It can be concluded that the transport system carried out by the wet etching fishmonger effect on the occurrence of abnormalities in behavioral symptoms, anatomic pathology outer and inner organs, the presence of bacterial disease and the decline in fish health conditions. Keywords : Betok fish, bacterial, transportation

First report on Asian fish tapeworm (Bothriocephalus acheilognathi) infection of indigenous mahseer (Tor tambra) from Nagan Raya district, Aceh province, Indonesia

Summary Muchlisin, Z. A., Z. Fuadi, A. M. Munazir, N. Fadli, W. Winaruddin , C. Nanda Defira & A. Hendri, 2015. First report on A sian fish tapeworm ( B othriocephalus acheilog nathi ) infection of indigenous mahseer ( T or ta m bra ) from N agan R aya district, A ceh province, I ndonesia . Bulg. J. Vet. Med. (online first). The aim of the present study was to examine the prevalence and intensity of the Asian fish tapeworm, Bothriocephalus acheilognathi on the indigenous mahseer fish Tor tambra . The fish samples were collected from Isie p River, Nagan Raya District as representative of wild population and from aqu a- culture ponds as representative of captive population. A total of 30 fish sam ples from Krueng Isep river and 30 fish samples from aquaculture fish ponds were examined in this study. The fish samples were abdominally dissected and t he alimentary tract s were taken and perforated . The alimentary co n- tents were placed onto P etri dish a nd observed for tapeworms. The samples of worm were photographed using stereo microscope. The results showed that the fish samples from aquaculture fishponds were infected by Bothriocephalus acheilognathi with the prevalence and intensity of 53.33% and 8.0 6, respectively, while no fish from the river was infected by cestoda.

Application of a Sustainable Fisheries Development Indicator System for Taiwan’s Aquaculture Industry

The benefits of aquaculture for humans worldwide have become increasingly important, especially in Asia. Although Taiwan does not have a high aquaculture output, the superior aquaculture techniques employed allow Taiwan to maintain competitiveness in the Asian region. The objective of this study was to evaluate the trend of sustainable aquaculture fishery development in Taiwan, and the potential problems that exist. This study used a sustainable development indicator framework with 4 dimensions to analyze the sustainable development of Taiwan's aquaculture fisheries. The results showed that between 2004 and 2009, economic indicators declined, posing substantial concerns for the sustainable management of Taiwan's aquaculture. The results for the ecological, social, and institutional dimensions demonstrated stability or slight increases. Although the indicators partially reflect the effects of government aquaculture policies, problems such as illegal aquaculture fish ponds, inaccurate sales data, and sales channels controlled by a limited number of fishmongers and middlemen remain. In summation, current aquaculture fisheries cannot achieve sustainability through production alone; instead, integrating the aquaculture fisheries with social humanities, environment and ecology, and resource management is required. • The results of this study showed that sustainable fisheries development indicator system (SFDIS) can be applied to evaluate the aquaculture policy performance well. • The experience of Taiwan's aquaculture policy could be a reference for the other countries, especially in East Asian region. • Taiwan experience shows, current aquaculture fisheries cannot achieve sustainability through production alone; instead, integrating the aquaculture fisheries with social humanities, environment and ecology, and resource management is required.

FISHPOND AQUACULTURE INVENTORY IN MAROS REGENCY OF SOUTH SULAWESI PROVINCE

Currently, fishpond aquaculture becomes an interesting business for investors because of its profit, and a source of livelihood for coastal communities. Inventory and monitoring of fishpond aquaculture provide important baseline data to determine the policy of expansion and revitalization of the fishpond. The aim of this research was to conduct an inventory and monitoring of fishpond area inMaros regency of South Sulawesi province using Satellite Pour l’Observation de la Terre (SPOT -4) and Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Apeture Radar (PALSAR). SPOT image classification process was performed using maximum likelihood supervised classification method and the density slice method for ALOS PALSAR. Fishpond area from SPOT data was 9693.58 hectares (ha), this results have been through the process of validation and verification by the ground truth data. The fishponds area from PALSAR was 7080.5 Ha, less than the result from SPOT data. This was due to the classification result of PALSAR data showing someobjects around fishponds (dike, mangrove, and scrub) separately and were not combined in fishponds area calculation. Meanwhile, the result of SPOT -4 image classification combined object around fishponds area.

Influence of the fish pond aquaculture effluent discharge on abiotic environmental factors of selected rivers in Northwest Poland

Pollution of rivers caused by human activity is a widely discussed problem, however there is not much attention paid to the changes of water quality that result from the inflow of effluent discharged from fish breeding ponds. The paper presents results of studies on changes of the abiotic parameters (hydrochemical and hydrological) of water observed in the yearly cycle between 2004 and 2008 in selected rivers of Northwest Poland. It was proved that the fastest reaction on the inflow of the effluent discharged from the fish ponds was reflected in changes of biogenic and organic compounds in the river water. The largest, i.e. threefold (rivers Krąpiel and Tywa) or even fourfold (rivers Rurzyca and Stepnica) increase in nutrients and organic matter was recorded during the pond effluent discharge into the rivers. At that time values of the organic matter ranged from 8.9 to 18.3mgO2/dm3 (BOD5), the nitrogen compounds from 16.868 to 26.930mgN/dm3, while the phosphorus from 1.928 to 6.353mgP/dm3. Interestingly, an additional dry mass of seston was recorded no earlier than the activity of the harmful element had been stopped and the river had resumed to the “initial” state (i.e. before the effluent discharge); that period varied from one to two months, depending on the river characteristics. The highest values of the dry seston mass (580.9mg/dm3) was recorded in river Krąpiel in November 2006. It seems that in spite of remarkable influence on values of individual physical and chemical indices of the river water quality, the effluent discharge from the fish ponds is not a factor hampering the self-purification processes of the rivers.

Geospatial modeling of pre-contact Hawaiian production systems on Molokaʻi Island, Hawaiian Islands

The geographic distribution and relative importance of traditional agricultural systems in Hawaiʻi, based on ethnohistoric and archeological data, is only partially understood. Knowledge of the size and distribution of these systems is critical in estimating island populations, production, and surplus, as well as for assessing societal dynamics and the sustainability of indigenous agricultural systems. We employ geospatial modeling using rainfall, elevation, soil type, streamflow, slope, and substrate age, to create a geographic information system (GIS) model for the distribution of four major production systems on Molokaʻi Island – intensive pondfield irrigation, intensive dryland cropping, extensive colluvial slope agriculture, and fishpond aquaculture. Model results were checked against archaeological data sets for known areas, testing for goodness of fit between model predictions and empirical field evidence. Our model predicts that Molokaʻi could have sustained 9.52 km 2 of irrigated pondfields, 7.98 km 2 of intensive dryland systems, and 18.5 km 2 of colluvial slope agriculture. Fishponds are estimated to have yielded 17.98 metric tons of fish protein per year. The total agricultural production for the island is calculated to be 41,490 metric tons per year (wet weight), with pondfield, dryland, and slope systems yielding 46, 17, and 37 percent of total production respectively. Our results indicate that colluvial slope cultivation, which has been largely ignored in previous studies, was a major contributor to Hawaiian agricultural production, especially on the geologically older islands. Pondfield irrigation and colluvial slope systems had higher caloric efficiency than intensive dryland field systems, providing greater surplus to labor ratios in areas with abundant land suitable to irrigation and slope cultivation. Surplus discrepancies likely influenced population distribution as well as sociopolitical dynamics between districts and among neighboring islands. The model has applicability to the entire Hawaiian archipelago and to other islands in Polynesia, where it may be used to estimate pre-contact agricultural production and carrying capacities, two main factors influencing pre-contact social and political dynamics in Hawaiʻi and other island groups.

Fish Pond Aquaculture in Cameroon: A Field Survey of Determinants for Farmers' Adoption Behaviour

Although fish farming in Cameroon started in the late 1940s, currently the country meets only half of its domestic demand for fish. This article examines the complex issue of farmers’ adoption decisions and attempts to answer why there is a lag in the diffusion process. The theory of behaviour modification and key variables of adoption form the conceptual framework of this study. The paper makes use of primary data obtained through semi-structured interviews, key informants and focus group discussion. This paper reveals that inputs provided by public or non-governmental bodies, favourable environmental conditions and socio-cultural attitudes act together as driving factors towards fish farming adoption. Little administrative presence and a low local effective demand for fish have a negative effect on the adoption process. Characteristics like trialability, relative advantage and complexity of the innovation exert a significant hindrance on farmers’ adoption behaviour, while compatibility and observability provide a certain explanation. The findings clearly support the observation that fish farming is an attractive activity for medium-scale farmers most of whom are able to: run several ponds, and manage feeding, maintenance, storage, transportation and marketing effectively. With regard to small-scale farmers, staple food cropping is seen to have a comparative advantage over fish farming. This study fills gaps in existing knowledge of fish pond aquaculture diffusion in Cameroon. To realize a positive impact on the adoption decision process of this activity, this article suggests donors focus on medium-scale farmers, on improving organizational structures of farmers, and on strengthening the fragile extension system and the research on fingerlings production.

From Exotic to Familiar, a Taste for Every Bud

From Exotic to Familiar, a Taste for Every Bud

Methanofollis formosanus sp. nov., isolated from a fish pond

A mesophilic, hydrogenotrophic methanogen, strain ML15(T), was isolated from an aquaculture fish pond near Wang-gong, Taiwan. The cells were irregular cocci, non-motile, 1.5-2.0 microm in diameter and Gram-negative. Cells of strain ML15(T) lysed easily in the presence of SDS (0.1 g l(-1)) and the S-layer protein had an M(r) of 138 800. The catabolic substrates utilized by this strain included formate and H(2)/CO(2), but not acetate, methanol, trimethylamine or secondary alcohols. Growth did not occur in minimal medium, but was observed when yeast extract and tryptone were added. Strain ML15(T) grew fastest at 37 degrees C, pH 6.6-7.0 and with 3 % NaCl. Acetate was not required for cell growth. Trace amounts of tungstate promoted cell growth. The G+C contents of DNA of Methanofollis aquaemaris N2F9704(T) and strain ML15(T) were 59.1 and 58.4 mol%, respectively. Sequence analysis of the 16S rRNA genes of strain ML15(T) and selected Methanofollis species revealed similarities of 95-97 %. Based on the data presented here, it is proposed that strain ML15(T) (=OCM 789(T)=DSM 15483(T)) represents a novel species, Methanofollis formosanus sp. nov.

Methanocalculus chunghsingensis sp. nov., isolated from an estuary and a marine fishpond in Taiwan.

Three novel halotolerant, hydrogenotrophic methanogens, designated strains K1F9705bT, K1F9705c and O1F9704a, were isolated from an estuary in Eriln Shi, Taiwan, and from a nearby marine water aquaculture fishpond. These isolates were irregular cocci that stained Gram-negative. Strains K1F9705bT and K1F9705c were non-motile, but strain O1F9704a was weakly motile with flagella. They were able to use formate and H2/CO2 to form methane, but they could not catabolize acetate, methanol, trimethylamine or secondary alcohols. Acetate was required for cell growth. Tungsten greatly stimulated the growth of strains K1F9705bT and K1F9705c, but did not affect the growth of strain O1F9704a. Optimal pH and temperature for growth of these three isolates were respectively 7.2 and 37 degrees C. Optimal NaCl concentration for growth was 0.5% for strain O1F9704a and 1.0% for strains K1F9705c and K1F9705bT. Moreover, all strains grew well at up to 8-12% NaCl. Analysis of the 16S rRNA gene revealed that these isolates are members of the genus Methanocalculus, but are distinct from Methanocalculus taiwanensis, Methanocalculus pumilus and Methanocalculus halotolerans, with sequence similarities of 98.4, 98.3 and 98.2%, respectively. In addition, strain K1F9705bT possessed 85, 80, 37, 29 and 10% DNA-DNA relatedness to strain K1F9705c, strain O1F9704a, M. pumilus, M. halotolerans and M. taiwanensis, respectively. Analysis of protein profiles and the Mr of surface (S)-layer glycoprotein subunits showed that these three new isolates are closely related to, but distinct from, known Methanocalculus species. A novel species, Methanocalculus chunghsingensis sp. nov., is proposed for strains K1F9705bT, K1F9705c and O1F9704a. The type strain is K1F9705bT (=OCM 772T=DSM 14646T).

Methanofollis aquaemaris sp. nov., a methanogen isolated from an aquaculture fish pond.

A novel methanogen, designated strain N2F9704T, was isolated from an aquaculture fish pond near Wang-gong, Taiwan. The cells were irregular cocci, non-motile, 1.2-2.0 microm in diameter and stained gram-negative. Cells of strain N2F9704T lysed easily by SDS treatment (0.1 g l(-1)) and the S-layer protein had an Mr of 137000. The catabolic substrates used included formate and H2+CO2, but not acetate, methanol, trimethylamine or secondary alcohols. The optimal growth parameters for strain N2F9704T were pH 6.5, 37 degrees C with 0.5% NaCl. Trace amounts of tungstate not only promoted growth but also extended the range of growth conditions. Analysis of the 16S rDNA sequence revealed a phylogenetic relationship to Methanofollis species and the name Methanofollis aquaemaris sp. nov. is therefore proposed for strain N2F9704T (= OCM 746T = CCRC 16166T). Additionally, the strain was infected with a novel coccus-shaped, enveloped virus with a diameter of 200 nm.