| 1. |
- Andrade, Carlos A. P., et al.
(author)
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Red Porgy, Pagrus pagrus, Larvae Performance and Nutritional Condition in Response to Different Weaning Regimes
- 2012
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In: Journal of the World Aquaculture Society. - : Wiley. - 0893-8849 .- 1749-7345. ; 43:3, s. 321-334
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Journal article (peer-reviewed)abstract
- Red porgy, Pagrus pagrus, is a candidate species for aquaculture diversification. The aim of this work was to assess whether an early supply of enriched Artemia (D1) or a direct step to dry diets (D3) would be advantageous weaning strategies for red porgy larvae, compared to a later supply of Artemia followed by dry diets (D2). Direct weaning to dry diet resulted in significantly lower growth, survival, pancreatic (trypsin and lipase), and intestinal (alkaline phosphatase) enzyme-specific activity, with the exception of leucine-alanine peptidase. The direct weaning strategy presented severe nutritional restrictions from early weaning stages with an associated delay of the maturation of digestive system. The two-step strategy presented in D1 and D2 resulted in comparable results in most parameters, including survival. Weaning using enriched Artemia as an intermediate step is confirmed as the most adequate strategy for red porgy larvae. Digestive enzymes and selected fatty acids correlated well with performance responses to dietary regimes, thereby supporting the use of these parameters as sensitive and reliable indicators of red porgy nutritional or physiological status during larval stages.
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| 2. |
- Duy, Duong The, et al.
(author)
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Assessment of technical, economic, and allocative efficiencies of shrimp farming in the Mekong Delta, Vietnam
- 2023
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In: Journal of the World Aquaculture Society. - : Wiley. - 0893-8849 .- 1749-7345. ; 54:4, s. 915-930
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Journal article (peer-reviewed)abstract
- This study applied a stochastic frontier production model to analyze the technical (TE), allocative (AE), and economic (EE) efficiencies of intensive shrimp farming households, and to identify socioeconomic and shrimp farm-specific factors (farm size, labor, feed, seed, chemicals/medicine) that influence the TE, AE, and EE of shrimp production in the Ca Mau, Ben Tre, Bac Lieu, and Tra Vinh provinces of the Mekong Delta, Vietnam. The AE was calculated based on TE and EE. The stochastic frontier production and cost function model were used to evaluate the EE and TE at the shrimp farming household level. The results showed that the mean TE, AE, and EE of shrimp farming systems were 75%, 68.5%, and 61.4%, respectively. Age, gender, education, experience, cooperatives, and technical training significantly impacted the efficiency of shrimp production. The results suggest that shrimp farmers can improve shrimp productivity and EE by decreasing feed cost (FEE) and medicine/chemical cost (MED) of farm inputs. The study showed that shrimp farmers who participated in training activities, cooperatives, or management boards of aquaculture associations were more technically efficient than other farmers. The findings of this study provide essential information about the TE, AE, and EE of shrimp production, which can help local policy makers and shrimp farmers in the region to make better decisions on how to improve the EE and sustainability of shrimp production in the future. There is a need for recommendations on how to improve policies, technical guidance, and training courses on feed management and feeding practices, water quality, and disease management, to help shrimp farmers in the coastal provinces of the Mekong Delta to improve their shrimp production efficiencies in the future.
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| 3. |
- Sauvage, Justine, et al.
(author)
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Bacterial exudates as growth-promoting agents for the cultivation of commercially relevant marine microalgal strains
- 2022
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In: Journal of the World Aquaculture Society. - : Wiley. - 0893-8849 .- 1749-7345. ; 53:6, s. 1101-1119
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Journal article (peer-reviewed)abstract
- In laboratory and industrial cultivation of marine microalgae, it is customary to enrich cultures with macronutrients (N, P), chelated trace metals, and vitamins at similar to 10(4) x concentrations found in nature to obtain high culture densities. Other naturally occurring growth-promoting compounds found in local seawater are not enriched and remain at environmental concentrations. Microalgae may thus be deprived of the mutualistic contributions of co-occurring microorganisms with which they have evolved complex chemical relationships. In the present study, we assess the direct (mixed bacteria-microalgae cultivation) and indirect (exposure to exudates only, without physical contact) effects of 10 bacterial strains on the growth of five marine microalgal strains used as feeds in marine aquaculture hatcheries. Bacterial strains were selected based upon previously reported growth-promoting characteristics in plants or microalgae, or known release of probiotics. Our experiments demonstrate superior stimulation of microalgal growth by bacterial exudates, and without the presence of the bacteria that produced these exudates. However, response to bacterial exudate enrichment was dependent upon the microalgae strain and bacterial pairing. Exudates from Bacillus, Mesorhizobium, arid Phaeobacter strains were most effective, with 22%-69% increases in microalgal specific growth rate. Such findings indicate that bacterial exudates accelerate rate-limiting processes governing nutrient acquisition, assimilation, or anabolism, and possibly algal release of exopolymeric substances. Maximal cell density, however, remained constrained by macronutrient limitation. Scaledup trials in an oyster hatchery confirmed the practical benefit of bacterial exudate culture medium enrichment and demonstrated the suitability of exudate-enriched microalgae to feed hatchery-reared bay scallops. This work presents a promising strategy to improve microalgal culture media formulations using bacterial exudate components as growth promoters, and is the first such study to identify specific pairings with relevance for aquaculture production.
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| 4. |
- Schagerström, Ellen, et al.
(author)
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Controlled spawning and rearing of the sea cucumber, Parastichopus tremulus
- 2022
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In: Journal of the World Aquaculture Society. - : Wiley. - 0893-8849 .- 1749-7345. ; 53:1, s. 224-240
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Journal article (peer-reviewed)abstract
- The red sea cucumber, Parastichopus tremulus, a cold water species with commercial potential, has recently attracted attention for wild harvest as well as for potential use in integrated multi-trophic aquaculture in Scandinavian countries. Overharvesting has put natural stocks of sea cucumbers at risk in several countries. Our goal was to develop a rearing protocol for P. tremulus to enable sustainable production of this species. This study presents results from spawning and larval rearing conducted in both Norway (NO) and Sweden (SWE) during May-August 2019. We describe spawning induction and behavior, fertilization success, embryonic and auricularia larval development rate for this species under laboratory conditions. The larvae were fed a mixture of three species of live microalgae (SWE) and algal paste (NO). Larval development rate and survival were monitored at four different temperatures (7, 10, 13, and 16 degrees C). Results showed faster development with increasing temperature. Daily food consumption rate was highest at the highest temperature. The combined effects of temperature and food availability on survival were investigated for the same four temperatures and three different feed concentrations. Only food availability affected the mortality rate, with the highest mortality in the low feeding regime of 1,000-2,000 cells ml(-1) day(-1).
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| 5. |
- Troell, Max, 1962-, et al.
(author)
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Perspectives on aquaculture's contribution to the Sustainable Development Goals for improved human and planetary health
- 2023
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In: Journal of the World Aquaculture Society. - 0893-8849 .- 1749-7345. ; 54:2, s. 251-342
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Research review (peer-reviewed)abstract
- The diverse aquaculture sector makes important contributions toward achieving the Sustainable Development Goals (SDGs)/Agenda 2030, and can increasingly do so in the future. Its important role for food security, nutrition, livelihoods, economies, and cultures is not clearly visible in the Agenda 21 declaration. This may partly reflect the state of development of policies for aquaculture compared with its terrestrial counterpart, agriculture, and possibly also because aquaculture production has historically originated from a few key hotspot regions/countries. This review highlights the need for better integration of aquaculture in global food system dialogues. Unpacking aquaculture's diverse functions and generation of values at multiple spatiotemporal scales enables better understanding of aquaculture's present and future potential contribution to the SDGs. Aquaculture is a unique sector that encompasses all aquatic ecosystems (freshwater, brackish/estuarine, and marine) and is also tightly interconnected with terrestrial ecosystems through, for example, feed resources and other dependencies. Understanding environmental, social, and economic characteristics of the multifaceted nature of aquaculture provides for more context-specific solutions for addressing both opportunities and challenges for its future development. This review includes a rapid literature survey based on how aquaculture links to the specific SDG indicators. A conceptual framework is developed for communicating the importance of context specificity related to SDG outcomes from different types of aquaculture. The uniqueness of aquaculture's contributions compared with other food production systems are discussed, including understanding of species/systems diversity, the role of emerging aquaculture, and its interconnectedness with supporting systems. A selection of case studies is presented to illustrate: (1) the diversity of the aquaculture sector and what role this diversity can play for contributions to the SDGs, (2) examples of methodologies for identification of aquaculture's contribution to the SDGs, and (3) trade-offs between farming systems' contribution to meeting the SDGs. It becomes clear that decision-making around resource allocation and trade-offs between aquaculture and other aquatic resource users needs review of a wide range of established and emergent systems. The review ends by highlighting knowledge gaps and pathways for transformation that will allow further strengthening of aquaculture's role for contributing to the SDGs. This includes identification and building on already existing monitoring that can enable capturing SDG-relevant aquaculture statistics at a national level and discussion of how a cohesive and comprehensive aquaculture strategy, framed to meet the SDGs, may help countries to prioritize actions for improving well-being.
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