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WOS:000589472000001; International audience; The Native Oyster Restoration Alliance (NORA) supports the protection and ecological restoration of the native European oyster, Ostrea edulis, and its habitat across its current and historical biogeographical range. NORA works to overcome barriers to the conservation, restoration, and recovery of the European oyster by providing a platform for the NORA community to collaborate and participate in knowledge exchange. NORA seeks to support responsible restoration practice, in compliance with biosecurity and sustainability. Against this background, the NORA community formulated a series of specific recommendations, the Berlin Oyster Recommendation, to support native oyster restoration by developing and applying best practice with the aim to recover healthy and resilient marine ecosystems. In combination with the Standards for Ecological Restoration (SER) and the Restoration Guidelines for Shellfish Reefs, the Berlin Oyster Recommendation is a relevant tool for successful and sustainable oyster restoration in Europe. The establishment of NORA working groups will support the implementation and further development of the six corresponding recommendations. Current NORA working groups cover site selection, biosecurity, production, and monitoring. The site selection working group will address the identification of suitable sites for oyster restoration to support policy relevant decision making and the conservation, reinforcement, or reintroduction of native oysters. The biosecurity working group will develop biosecurity guidelines for native oyster restoration in Europe. The production working group will assess the potential of standards for seed oyster production and supply in order to enhance production appropriate for restoration purposes. In close collaboration with the Native Oyster Network - UK & Ireland (NON), the monitoring working group will produce a monitoring guidelines handbook to provide metrics and methods that will be suitable across the range of O. edulis projects in Europe for the documentation of restoration success and ecosystem recovery. The Berlin Oyster Recommendation was examined and interpreted by NORA experts in the context of the further development of joint guidelines for the practice of successful and sustainable native oyster restoration.

Information relating to the effects of phytic acid (PA), an anti-nutritional factor (ANF) commonly found in plant protein ingredients, on the growth performance, feed conversion ratio (FCR), nutrient utilisation and whole proximate composition in the Malaysian giant freshwater prawn, Macrobrachium rosenbergii, is lacking. Replicate groups of M. rosenbergii (mean initial carapace length of 6.03 ± 0.30 mm; mean initial weight of 0.29 ± 0.02 g; n = 20 per replicate group) were fed graded levels of PA for 140 days. The basal diet, to which different levels of PA were added to obtain 0.26 (control), 6.48, 11.28, 16.53, 21.45 and 26.16 g PA kg− 1, contained fishmeal, soy protein concentrate and wheat meal. Terminal sampling indicated that the growth performance, FCR and survival did not differ significantly between the groups receiving the different inclusions of PA within their diets. The apparent protein, lipid and energy utilisation responded negatively, decreasing significantly (p 0.05) on the M. rosenbergii reared under the experimental conditions that were employed here.

Survival and growth of postlarvae (PL) of Macrobrachium rosenbergii (De Man 1879) were investigated under different alkalinity (25 to 500 mg·L− 1 and total hardness (25 to 1000 mg·L− 1). 45 days old PL feed with a rich protein diet (38%) comprising mussels, green beans and commercial shrimp pellets, where individually held in deionised water flow through systems with chemicals added according to the HMSO (1969) formula to make up the required calcium and carbonate concentrations. Increasing alkalinity reduced the growth rate and survival of PL of M. rosenbergii. An alkalinity concentration of 250 mg·L− 1 or above was lethal for PL of the species as total harness increased. Total hardness as high as 1000 mg·L− 1 however, did not have a significant effect in the growth rate or survival as long as the alkalinity was 100 mg·L− 1 or lower. Thus suggesting that water with high hardness and low alkalinity in different countries could be used for the production of the species. Statement of relevance Water suitability for the production of freshwater prawn Calcareous exoskeleton in crustaceans provides protection and support, but also imposes severe limitations, since growth is only possible by moulting. Total hardness and alkalinity of the water are important considerations in the culture of Macrobrachium rosenbergii, since they represent the concentrations of cations (calcium-magnesium) and anions (carbonates), necessary for the mineralization of the exoskeleton. M. rosenbergii has a wide range of tolerance to most of the critical parameters in aquaculture. However, the optimum levels of combinations of both alkalinity and total hardness factors for the species are yet to be fully identified. Therefore, the chemical composition of the different water bodies, and their variations, demonstrate that site selection is of paramount importance for the culture of crustaceans, depending on their requirements for alkalinity and total hardness, and the aim of this study was to investigate the effects of environmental alkalinity and total hardness in the development of PL of M. rosenbergii, as well as to identify the maximum tolerance limits and the optimum range of levels of both factors, individually and as a synergistic effect for the prawns. It was found that alkalinity levels of 250 mg L− 1 as CaCO3 were lethal for the species and that PL of the species could grow and survive at total hardness levels of 1000 mg L− 1 as CaCO3 as long as the alkalinity was lower than 100 mg L− 1 as CaCO3.

The presence of anti-nutritional factors such as phytic acid (PA) in a number of potentially useful plant ingredients has been a major impediment to their use as replacements for fishmeal in aquafeeds. This study builds on an earlier studying investigating the growth performance and nutrient utilisation in the juvenile Malaysian giant river prawn, Macrobrachium rosenbergii exploring the effects and interactions of dietary PA with minerals on growth (somatic tissue). Additionally, the study set out to determine the changes in whole-body mineral composition and also on muscle tissues and the carapace, when different levels of PA were included within the diet. The hypothesis under test was that PA, as a mineral-binding agent by chelating di- and trivalent cations inhibits mineral availability. To explore this, effects of graded levels of PA (i.e. 0.26–control, 6.48, 11.28, 16.53, 21.45 and 26.16 g PA kg−1) on the moult frequency and mineral availability in juvenile M. rosenbergii (mean initial carapace length of 6.22 ± 0.52 mm; mean initial weight of 0.20 ± 0.01 g; n = 20 per replicate) fed over a period of 140 days were determined. The levels of PA assessed in this feed trial had no major detrimental effects on moult frequency. Negative effects (p, This project was supported by the Ministry of Higher Education Malaysia and University Malaysia Terengganu (UMT) as part of a PhD programme of study.

The African River prawn Macrobrachium vollenhovenii is the largest of the local Palaemonidae prawns along the Cameroonian coast and an important target species for fisheries and aquaculture. A preliminary study on larviculture of this species was carried out at the IRAD-AQUASOL hatchery in Kribi, Cameroon. Berried females M. vollenhovenii were obtained from the Lobe and Lokoundje Rivers in the Southern Region, typical Lower Guinea rainforest streams. The larval rearing system consisted of a single recirculation system of four 65 L cylindrical plastic containers connected to a submerged biological filter container (65 L). Experiments were conducted three times in the same condition, with two batches of larvae reared separately in duplicate per experiment, at a density of 40/L, temperature 26°C, and salinity 16%. Larvae were fed from 1 day after hatching until metamorphosis to postlarvae (PL) with newly hatched Artemia nauplii, three times daily at the rate of 5 nauplii per mL water. The number of newly hat...

Aquaculture is currently the fastest expanding global animal food production sector and is a key future contributor to food security. An increase in food security will be dependent upon the development and improvement of sustainable practices. A prioritization exercise was undertaken, focusing on the future knowledge needs to underpin UK sustainable aquaculture (both domestic and imported products) using a ‘task force’ group of 36 ‘practitioners’ and 12 ‘research scientists’ who have an active interest in sustainable aquaculture. A long list of 264 knowledge needs related to sustainable aquaculture was developed in conjunction with the task force. The long list was further refined through a three stage process of voting and scoring, including discussions of each knowledge need. The top 25 knowledge needs are presented, as scored separately by ‘practitioners’ or ‘research scientists’. There was similar agreement in priorities identified by these two groups. The priority knowledge needs will provide guidance to structure ongoing work to make science accessible to practitioners and help to prioritize future science policy needs and funding. The process of knowledge exchange, and the mechanisms by which this can be achieved, effectively emerged as the top priority for sustainable aquaculture. Viable alternatives to wild fish-based aquaculture feeds, resource constraints that will potentially limit expansion of aquaculture, sustainable offshore aquaculture and the treatment of sea lice also emerged as strong priorities. Although the exercise was focused on UK needs for sustainable aquaculture, many of the emergent issues are considered to have global application.

The livelihoods of a large number of farmers are associated with freshwater prawn (Macrobrachium rosenbergii) farming in gher (modified rice fields with high, broad peripheral dikes) systems in southwest Bangladesh. Most farmers integrated prawn with fish and rice in their gher and followed extensive methods using low inputs. Although farmers have improved their social and economic conditions through prawn farming, constraints include high production costs, low supply of wild fry and snail meat as prawn feed, lack of technical knowledge of farmers, and negative environmental impacts.

There is a growing need to control, prevent or minimise the devastating effects of disease in crustacean culture without recourse to toxic chemicals or antibiotics. In keeping with approaches to disease control in fish and higher mammals, interest is developing in compounds that confer protection and/or enhance immune reactivity to likely pathogens in shellfish (sometimes, erroneously, referred to as as "shellfish vaccines"). The agents currently under scrutiny for crustaceans include glucans, lipopolysaccharides and killed bacterial cells. They are thought to act as "immuno-stimulants" because of their known effects on the crustacean immune system in vitro. A number of papers are now appearing in the literature claiming to demonstrate their positive impact on immunity and immunity and disease resistance. This review article considers the problem of disease and its control in crustacean farming, describing the types of capability in cultured species. Analysis of the validity of the results of many of the published studies raises questions about the value of these compounds for cost-effective control of infection in aquaculture, especially for long lasting protection in both adults and juveniles. This review further discusses the potential risks to the wellbeing of the stock animals from repeated use of these agents and makes the case for rigorous testing of putative stimulants, at the gene, protein and functional levels, as well as for the need to consider alternative strategies and approaches to disease control.

Forty post-larval giant freshwater prawns (Macrobrachium rosenbergii) were weighed, measured, marked and placed in groups of 4. Social interactions were screened daily, moults were recorded and the nature and stability of dominance interactions characterised. Half of the prawns were screened for resting oxygen consumption before group formation. In most groups, one or two individuals ('dominants') consistently won the majority of interactions in which they were involved, while others ('subordinates') consistently lost; the remainder were classified as of intermediate social status. Prawns lost more fights on the day before a moult, but despite this, rank was retained after moults. Neither initial size nor growth rates varied with status, but prawns that became dominant had significantly higher resting metabolic rates before group formation than those that became subordinate. Thus in M. rosenbergii the outcome of aggressive interactions can be predicted from the metabolic physiology of the animals although...

This paper describes the successful use of two tagging systems, both produced by Northwest Marine Technology Inc., on larval and postlarval giant freshwater prawns, Macrobrachium rosenbergii. Visible implant (VI) elastomer tags (a coloured liquid that solidifies under the epidermis) were used on stage XI larval prawns (mean weight 0.01 g) and postlarval prawns (mean weight 0.07 g). VI alphanumeric tags (small biocompatible plastic labels also inserted under the epidermis) were tested on postlarval prawns (from a weight of 0.5 g). Tags were inserted using clove oil as anaesthetic, and survival, mortality and growth rates of tagged animals were compared with those of controls that were handled but not anaesthetized or marked. Twenty per cent of the larval prawns (the smallest of the group) died just after tagging, but thereafter the remaining prawns survived well, as did all the tagged postlarval prawns. Visibility of the VI elastomer tags in larval prawns deteriorated with time, though 79% of marks were still visible to the naked eye 70 days after tagging. VI elastomer tags in the postlarval group remained clearly visible for up to 100 days. Visibility of the VI alphanumeric tags fell shortly after tagging, but remained adequate thereafter. Moult rates in control and tagged animals were the same in larvae with VI elastomer tags and postlarvae with VI alphanumeric tags, but the moult rate in the postlarval prawns given elastomer tags was slower than in controls. Rates of growth were similar in tagged (elastomer and alphanumeric) and control postlarval prawns, once the size-dependent mortality of tagged larval prawns was taken into account. We conclude that VI elastomer tags could be used to mark small numbers of individual larval and immediately postlarval prawns for periods of several months, and that VI alphanumeric tags could be used to mark an unlimited number of individuals from a size of approximately 0.5 g.

The application of different combinations and levels of pellet formulated feed and chicken manure to ponds stocked with Macrobrachium rosenbergii (de Man) did not result in any significant differences in water quality, sediment chemistry, or benthic macroinvertebrate populations. Water chemistry data indicated that all ponds were eutrophic. Chlorophyll was strongly correlated with total nitrogen, but not with total phosphorus, suggesting that nitrogen limited algal biomass. There was evidence that added organic matter was rapidly decomposed and mineralized. The sediments appeared to act alternately as sources and sinks of nutrients, although there was least variation in sediment nutrient levels in the treatment which received manure only. Applied pelleted feed was directly consumed by the prawns. In the absence of pelleted feeds, macrobenthos appeared to limit prawn growth after 1 month of culture. Simple nutrient mass-balance equations indicated that the losses of nitrogen, phosphorus and carbon from the treatments receiving feed were not dissimilar to previously reported values in finfish culture.

The effects of the frequency of manure application (twice weekly, weekly and fortnightly) on prawn production and pond dynamics in culture of Macrobrachium rosenbergii (de Man) were assessed. Juvenile freshwater prawns were cultured for 100 days using pelleted feed and organic fertilizer. Results showed that the greatest (but not significantly different) marketable prawn yield was achieved with fortnightly manuring, but the most stable pond environment as based on oxygen dynamics, developed with weekly fertilization. The highest concentrations of chlorophyll, nitrogen and phosphorus occurred with fortnightly applications, but so too did the lowest ratio of gross primary production: respiration. System dynamics are discussed.

Three meals were prepared from Penaeus monodon head waste by drying the raw material in a solar simulator, drying in an oven or blanching the raw material followed by partial de-watering under pressure and air drying. A further three meals were prepared by passing batches of raw or blanched shrimp head waste through a commercial meat/bone separator. The meat fraction was subsequently dried (MBDD) or ensiled. Separated meals contained around 6% less ash, 5% less chitin and 7.5% more protein than unseparated meals but the procedure failed to remove all the exoskeletal material. Separated meals also contained higher levels of astaxanthin and canthaxanthin than solar or oven-dried meals. The highest levels of n−3 polyunsaturated fatty acids (PUFAs) were found in separated meals. However, blanching the raw material prior to processing led to decreased PUFA content, higher free fatty acid levels and significantly higher (P < 0.05) peroxide values. All the meals were found to be deficient in arginine and methionine plus cystine but separated meals contained greater quantities of the remaining essential amino acids and had essential amino acid indices greater than 0.70. Experimental rations were prepared incorporating either 54% fish meal or 31% of the solar-dried, oven-dried or MBDD shrimp head meals plus sufficient fish meal to generate isoproteinaceous diets. Each diet was fed to triplicate groups of 40, juvenile Penaeus monodon in a 50-day growth trial. Diets containing shrimp head meal performed significantly (P < 0.05) better in terms of final individual weight, feed conversion ratio and production compared with the 54% fish meal based diet. The diet containing separated shrimp head meal produced the best response, followed by the diets containing oven-dried and solar-dried meal, but the differences were not statistically significant. Similar trends were noted for specific growth rate (SGR) and survival. Tests on the experimental diets indicated that the incorporation of shrimp head meals reduced water stability but increased diet palatability when compared to the fish meal based diet.

Evidence of calcium-stimulated dephosphorylating enzyme activity was found in the gills of the giant freshwater prawn Macrobrachium rosenbergii . The activity of the enzyme was influenced by environmental alkalinity. Branchial enzyme activity was measured in postmoult and intermoult prawns exposed to low (25 mg/l) and high (250 mg/l) alkalinity waters maintained at 20 mg/l total hardness. At low environmental alkalinity, the enzyme activity was higher in postmoult (2.11 μmol Pi mg/protein/hr) than in intermoult prawns (0.58 μmol Pi mg/protein/hr) while at high alkalinity enzyme activity was equally high in both postmoult and intermoult prawns (1.29 and 1.30 μmol Pi mg/protein/hr respectively). The activity in postmoult prawns did not differ significantly at the low and high alkalinities.

Eight semi-purified diets were formulated to investigate the effects of dietary lipid and lecithin levels on the performance and carcass composition of post-larval Penaeus monodon Fabricius. Supplementary soyabean lecithin levels from 0 to 9% and total dietary lipid (cod liver oil:soyabean oil at a ratio of 3:1) levels from 3·5 to 12·5% at 3% increments were tested in diets that were isonitrogenous and isoenergetic. The diets were fed for 50 days to triplicate groups of post-larval P. monodon held in a laboratory marine recirculated water system. Despite poor overall performance due to the purified dietary ingredients, the absence of basal lipids and/or lecithin was found to result in the poorest performance. Optimum production was obtained with a diet containing 3% basal lipid and 3% lecithin at a total lipid level of 6·5%. The addition of dietary lecithin (particulariy at 46·63% of the total lipid) at up to 3% in terms of growth, feeding efficiency and production or 6% in terms of survival significantly (P < 0·05) increased shrimp production. Lecithin was therefore probably acting as a growth, survival and/or phago-stimulant in P. monodon. The total lipid requirements are consistent with those reported by other workers for penaeid shrimp, and are probably a result of the requirement for essential fatty acids, the stimulant properties of lecithin and the calorigenic effects of high dietary lipid levels.

The effects of formulated feed and organic fertiliser on aquatic and benthic bacterial populations and on production of the freshwater prawn Macrobrachium rosenbergii (de Man) were assessed. Prawns were cultured in pond enclosures to which pelleted feed and/or chicken manure were added. Prawn survival was high but growth poor. Total bacterial abundance, mean cell volume and biomass, determined respectively by epifluorescence microscopy, image analysis and conversion calculation, illustrated the effect of treatment on the water and sediment bacterial populations. Differences in bacterial abundance and mean cell size were evident between treatments. The discussion considers the importance of bacterial productivity and food web dynamics.

Growth and carapace mineralization of Macrobrachium rosenbergii juveniles, (0.01–0.5 g) were investigated under conditions of different water hardness from 9 to 326 mg l −1 CaCO 3 . Growth was maximal at −1 CaCO 3 , did not change significantly at lower hardness levels but declined at higher levels. Survival was impaired at the highest hardness levels tested. Greater deposition of calcium in the carapace occurred in low-hardness water and the lower levels of calcium found in cast carapaces from these prawns indicated greater withdrawal of calcium from the carapace before moulting.

The survival and development rate of Macrobrachium rosenbergii and M. nipponense larvae were compared. M. nipponense was found to have 20% higher survival and a faster rate to metamorphosis than M. rosenbergii . Almost two larval cycles of M. nipponense could be completed within the time required for one cycle with M. rosenbergii . Based on the larval stage alone, culture of M. nipponense is attractive.

1. 1. The proximate (water, protein, lipid, mineral ash) and elemental (carbon, nitrogen, phosphorus) composition of eggs of the freshwater prawn Macrobrachium rosenbergii (de Man, 1879) (Crustacea, Decapoda) were determined in relation to embryonic development. Eggs were sampled at four intervals during development, ranging from day 1 (newly spawned) to day 16 (about to hatch). 2. 2. Egg dry mass, lipid and carbon content all decreased during development as reserves were utilized; at the same time both water and mineral ash content increased. Although the mean content of both nitrogen and protein declined during development these were not statistically significant due to a high variance. Egg phosphorus content remained constant throughout development. 3. 3. In the lipid fraction triacylgycerol fatty acids provided the major fuel, although phospholipid was also utilized. The most important substrates were 16:0 and 18:1 fatty acids. 4. 4. There were strong suggestions of an initial increase in egg lipid content during the first 5 days of development, though this was not statistically significant and the source of the extra material is unknown.

In a study of the factors that influence metabolic rate in the giant freshwater prawn Macrobrachium rosenbergii, resting oxygen consumption (ROC) was measured in 90 post-larvae ranging in size from 0.1 to 2.8 g. As in many other animal species, ROC was strongly negatively related to body weight. A stressful event (anaesthesia with or without tagging) caused a sharp increase in the ROC that disappeared over a time scale of hours. As has been demonstrated for other species of crustaceans, ROC was highest in prawns in the pre-moult stage. Individual differences in ROC among prawns handled in the same way and in the same moult stage persisted over a period of hours, but not over days. It remains unclear, therefore, whether early differences in resting metabolic rate can explain the conspicuous differences in growth rate that are found in this species during the first few weeks of life and that profoundly influence subsequent life history events.

The potential of organic fertilizer as a partial replacement for formulated feeds in pond culture of Macrobrachium rosenbergii (de Man) was assessed. Stocking densities reflected commercial semi-intensive levels and the duration of the trial approached a complete grow-out cycle. Mean weight and growth rate were examined in four treatments receiving varying levels of feed and manure. Heaviest prawns and fastest growth were evident in the treatment with decreased-feed-increased-manure. Production assessed as marketable percentages (74.56, 52.21, 13.28 and 11.12) resulted in significantly different marketable yields of 2029, 1284, 336 and 103 kg/ha/year for decreased-feed-increased-manure, feed-plus-manure, feed-only, and manure-only respectively assuming 2-6 batch cycles per year under prevailing conditions. Total survival was significantly highest in feed-only (72.80%), intermediate in feed-plus-manure (40.59%) and decreased-feed-increased-manure (36.32%), and lowest in manure-only (26.77%) treatments. Prawns were separated at harvest into four morphotypes as berried females, females without eggs, immature males and adult males. Average individual weight and group bicmass were determined for each morphotype. Only prawn production data are presented here. Analyses of water, soil and benthic fauna will be presented in future publications.

A survey was carried out in Karimun Jawa, a group of islands off the north coast of Central Java, in order (1) to investigate the environmental effect of the collection of giant clam shells used for floor tile manufacture, (2) to investigate the distribution and abundance of living populations of Tridacna spp. and to determine whether the larger species of giant clams are still to be found in the area and (3) to determine the suitability of this area for reseeding of giant clam species for mariculture and/or fishery development. Results showed that the collection of T. gigas shells for the manufacture of floor tiles did not have the same damaging effect on the coral environment as reported elsewhere. They also showed that populations of T, crocea, T. maxima and T. squamosa were still thriving while T. gigas, H. hippopits and T. derusa were extremely rare if not actually extinct, one individual alone of T. derasa being found. The potential for reintroduction of these latter species and for the encouragement of mariculture or fishery development into these islands seems great and is strongly advocated.

The uptake and accumulation of inorganic mercury by lobsters, from seawater containing levels of 10 to 100 ppb, was studied over periods of up to 50 days, using radiochemical neutron activation analysis. These results were amplified by the use of radioisotope tracer experiments. It was found that the gills and the green glands accumulated the most mercury and that the metal could be excreted via the urine. Histological studies showed that long-term exposure to mercury resulted in progressive necrosis of the green glands, whereas other organs were unaffected.