Grow-out Systems Research Articles

Optimal growth and feeding behaviour of the valuable bait Halla parthenopeia (Polychaeta: Oenonidae) in small-scale rearing systems

Commercial farming of polychaetes used as baits in recreational fishing and feed supplements for aquaculture has been regrettably limited to a few species. The rearing conditions and diet that optimize the survival and growth remain largely unknown for most species. This study aimed at improving the current knowledge on the rearing of the large bivalve-feeder polychaete Halla parthenopeia, one of the most appreciated and expensive baits by Mediterranean fishermen. We set up a laboratory rearing system for H. parthenopeia to address several management procedures and solutions aimed at improving the rearing method that has been employed so far. We also provide a detailed reconstruction of feeding behaviour and prey preferences which were unknown for the Mediterranean populations. Finally, we assessed growth when fed on commercial, intact clams or artificially opened clams. The latter fed has been never tested in previous studies on Halla species and simulates commercial waste clams, a potential low-cost resource for polychaete maintenance. The setting up of a grow-out system based on single worms maintained in small PET containers on the bottom of recirculating aquaria permitted the non-stressful manipulation of H. parthenopeia and an easy management of the aquarium system. We observed that polychaetes consumed both C. gallina and R. philippinarum, showing a nocturnal foraging behaviour consisting in three phases: searching, handling, and feeding. The duration of handling + feeding period (1–4 h) depended on bivalve size. Offering intact R. philippinarum clam, a significant positive correlation between the predator and prey size occurred i.e. the smaller the predator, the smaller the prey-size selected, probably because less time and energy were required for handling. The same behaviour was observed also for the congeneric Halla okudai and in H. parthenopeia from the Suez Canal. Polychaetes preferred feeding on open clams than intact clams, independently from clam and worm size. An increase in the daily predation rate (up to 300%) and growth increment (up to 250%) was found for H. parthenopeia feeding on open clam, maybe for the lack of energetic cost for prey handling. These results suggest that an indoor small-scale production of H. parthenopeia fed with waste clams could meet the demand of the angling community and support further biotechnological applications of this polychaete.

Assessing Productivity and Economic Potential of Pond-Based Culture of Sandfish (Holothuria scabra) and Babylon Snail (Babylonia areolata) in Monoculture and Four Different Coculture Arrangements

The aim of this study was to create an economic decision-making tool to allow farmers and stakeholders to make informed decisions around costs, benefits, and risks involved in production of sandfish, Holothuria scabra, and Babylon snail, Babylonia areolata, in different coculture arrangements based on a sound economic framework. A small-scale (0.16 ha) farm operation in Vietnam was modelled using production data obtained in previous studies to represent the costs and returns of rearing sandfish in tank-based nursery systems and in pond-based coculture grow-out systems. Sandfish and Babylonia monoculture was compared with three coculture models where the two species were separated, and the amount of pond area allocated to each ranged from 25% to 75%. A fourth coculture model (Co-4; “comingled”) was assessed where the two species were not separated and shared 100% of the substrate. The sandfish monoculture system produced 487 kg of sandfish at an annual cost of USD 5,616, providing an annual return of USD –3,521. The largest annual cost associated with sandfish monoculture was labor (USD 8.04 per kg). Pond monoculture of Babylon snail returned USD 1,876 annually, with an annual production cost of USD 19,858. Feeding represented the largest production cost associated with Babylonia monoculture of USD 14,340 per annum, or USD 5.11 per kg. Sandfish monoculture and Babylonia monoculture returned benefit–cost ratios of 0.37 and 1.09, respectively. The coculture model with pond area divided 50:50 between sandfish and Babylonia during grow-out, produced 258 kg of sandfish and 2,584 kg of Babylonia over a 359-day production cycle. This equates to USD 1,108 and USD 20,001 annual production of sandfish and Babylonia, respectively. After production costs, this model provided a return of USD 2,309 annually at a benefit–cost ratio of 1.12. The comingled culture model, Co-4, provided the greatest annual return of USD 6,019 and a benefit–cost ratio of 1.24. Results of this study build on previous research into practical aspects of sandfish/Babylonia coculture and provide a more complete picture of the potential application of this research to improve livelihoods and income of small-scale farmers in Vietnam.

Recent advances in seaweed seedling production: a review of eucheumatoids and other valuable seaweeds

Modern seaweed farming relies heavily on seedlings from natural beds or vegetative cuttings from previous harvests. However, this farming method has some disadvantages, such as physiological variation in the seed stock and decreased genetic variability, which reduces the growth rate, carrageenan yield, and gel strength of the seaweeds. A new method of seedling production that is sustainable, scalable, and produces a large number of high-quality plantlets is needed to support the seaweed farming industry. Recent use of tissue culture and micropropagation techniques in eucheumatoid seaweed production has yielded promising results in increasing seed supply and growing uniform seedlings in large numbers in a shorter time. Several seaweed species have been successfully cultured and regenerated into new plantlets in laboratories using direct regeneration, callus culture, and protoplast culture. The use of biostimulants and plant growth regulators in culture media increases the seedling quality even further. Seedlings produced by micropropagation grew faster and had better biochemical properties than conventionally cultivated seedlings. Before being transferred to a land-based grow-out system or ocean nets for farming, tissue-cultured seedlings were recommended to undergo an acclimatization process to increase their survival rate. Regular monitoring is needed to prevent disease and pest infestations and grazing by herbivorous fish and turtles during the farming process. The current review discusses recent techniques for producing eucheumatoid and other valuable seaweed farming materials, emphasizing the efficiency of micropropagation and the transition from laboratory culture to cultivation in land-based or open-sea grow-out systems to elucidate optimal conditions for sustainable seaweed production.

​​Nursery Rearing of Penaeus vannamei in Biofloc Systems with Different Salinities and Organic Carbon Sources

Background: Nursery rearing of Penaeus vannamei became inevitable in the Indian shrimp farming industry, since intensification of culture practices in grow-out systems caused nitrogenous wastes accumulation, diseases, mortality and premature harvests resulted in high food conversion ratio, lower production and profits. The nursery rearing in traditional water exchange systems often getting failure because of nitrogenous waste accumulation. Hence, the present experiment was planned to rear P. vannamei in bioflocs systems (BFS) with different salinities and carbon sources. Methods: The experiment was conducted in 0.22 m3 tanks with three different salinity groups viz., 35 ppt, 20 ppt and 5 ppt and in each salinity sugar, molasses used as carbon sources to maintain an estimated C/N ratio of 15:1 and controls without carbon sources. Experimental tanks were stocked @6 post larvae/l, with pre-salinity acclimatized P.vannamei seeds having 0.0029±0.0003g size and nursed for a period of 5 weeks. Result: The nitrogenous waste accumulation was reduced significantly (p less than 0.05), also average body weight and survival rate of the seeds showed significant difference (p less than 0.001) between treatments and controls and within treatments (p less than 0.05). Salinity, carbon sources and their interaction influenced the growth characteristics significantly (p less than 0.01). The present experiment manifested promising results of bioflocs nurseries in rearing of P. vannamei seeds at different salinities.

Forests, plantations and orchards

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Typology of farming systems in brackishwater ponds in the Philippines

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Institution and governance - PROSHIKA's role as a civil society organization in aquaculture

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Open sea

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Mudflats

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Large sustainable integrated shrimp farm in Indonesia

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Environmental carrying capacity for sustainable shrimp farming

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Shrimp and prawn post-larvae collection and impacts in Bangladesh

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Effectiveness of children as a transfer agent for basic aquaculture technology in rural Bangladesh

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Developing akoya pearl culture on the Australian east coast, challenges and constraints

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Seed production and grow-out of walking catfish (Clarias macrocephalus)

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Commercial aquaponic system prototype, University of the Virgin Islands

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Seed production and grow-out of sand goby (Oxyeleotris marmoratus) in Vietnam

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Periphyton-based aquaculture

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Seed production and grow-out of yellow catfish in China

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Farming carps in leased ponds by groups in Chandpur, Bangladesh

This datasheet on Farming carps in leased ponds by groups in Chandpur, Bangladesh covers Identity, Overview, Environmental Requirements, Growout Systems, Related Content, Further Information.