Distribution, occurrence and biotoxin composition of the main shellfish toxin producing microalgae within European waters: A comparison of methods of analysis.

Harmful algal blooms (HABs) are a natural global phenomena emerging in severity and extent. Incidents have many economic, ecological and human health impacts. Monitoring and providing early warning of toxic HABs are critical for protecting public health. Current monitoring programmes include measuring the number of toxic phytoplankton cells in the water and biotoxin levels in shellfish tissue. As these efforts are demanding and labour intensive, methods which improve the efficiency are essential. This study compares the utilisation of a multitoxin surface plasmon resonance (multitoxin SPR) biosensor with enzyme-linked immunosorbent assay (ELISA) and analytical methods such as high performance liquid chromatography with fluorescence detection (HPLC-FLD) and liquid chromatography–tandem mass spectrometry (LC–MS/MS) for toxic HAB monitoring efforts in Europe. Seawater samples (n = 256) from European waters, collected 2009–2011, were analysed for biotoxins: saxitoxin and analogues, okadaic acid and dinophysistoxins 1/2 (DTX1/DTX2) and domoic acid responsible for paralytic shellfish poisoning (PSP), diarrheic shellfish poisoning (DSP) and amnesic shellfish poisoning (ASP), respectively. Biotoxins were detected mainly in samples from Spain and Ireland. France and Norway appeared to have the lowest number of toxic samples. Both the multitoxin SPR biosensor and the RNA microarray were more sensitive at detecting toxic HABs than standard light microscopy phytoplankton monitoring. Correlations between each of the detection methods were performed with the overall agreement, based on statistical 2 × 2 comparison tables, between each testing platform ranging between 32% and 74% for all three toxin families illustrating that one individual testing method may not be an ideal solution. An efficient early warning monitoring system for the detection of toxic HABs could therefore be achieved by combining both the multitoxin SPR biosensor and RNA microarray.

Exploring Financial Inclusion for Smallholders: Promoting the Sustainable Development of Smallholder Aquaculture in Developing Countries

Thesis (Master's)--University of Washington, 2016-08

Disponibilité à des fins d'aquaculture des différents âges de thon rouge en atlantique est

In order to clear up possibilities to get bluefin tuna of various age in Eastern Atlantic, main conclusions on availability of bluefin in Eastern Atalntic are given, using results of International Commission for Conservation of Atlantic Tuna.

Improving income and livelihood of poor farming household in Bangladesh through adoption of improved aquaculture technologies and varieties

Fish are an important part of Bangladeshi culture and diet. Bangladesh ranks among the top five freshwater fish producers in the world. Fish are abundant in the thousands of rivers, ponds, lakes and seasonal floodplains across the country. They are a major source of protein for people living near these water bodies. In Bangladesh, many households depend on fish farming for their livelihood. By growing fish in homestead ponds, households have a consistent supply of nutritious fish and can sell the surplus for an income. The USAID-funded Cereal Systems Initiative for South Asia in Bangladesh (CSISA-BD) aimed to increase the income of farming households through increased productivity of aquaculture systems. Key activities of the project included developing and disseminating appropriate improved agricultural technology and quality fish seeds to improve livelihoods, food security and nutrition.

Understanding the gender dimensions of adopting climate-smart smallholder aquaculture innovations

This study explored how climate-smart agricultural and aquaculture innovations may lead to more successful climate adaptation efforts and enhanced resilience for both men and women in households and across communities, as well as to improved and equitable outcomes in terms of income, nutrition and livelihood opportunities. Specifically, it investigated efforts to target women with household aquaculture innovations to understand (1) if such approaches enable women to use or benefit from them; (2) if and how usage impacts the sustained use of these innovations; and (3) if it would be possible to scale out these innovations to achieve large scale development outcomes.

Improving Employment and Income through Development of Egypt’s Aquaculture Sector (IEIDEAS) project

The Swiss Agency for Development and Cooperation (SDC)-funded Improving Employment and Income through Development of Egypt’s Aquaculture Sector (IEIDEAS) project was implemented by WorldFish in partnership with CARE Egypt and the Egyptian Ministry of Agriculture and Land Reclamation from 2011 to 2014 and later extended to November 2015. The project focused on four governorates with significant aquaculture production (Kafr El Sheikh, Behera, Sharkia and Fayoum) and one governorate (El Mineya), where aquaculture was a new activity. The project was based on a value chain analysis conducted by WorldFish in September 2011 that identified the aquaculture value chain as a significant employer, particularly in rural areas. The analysis suggested that there was scope to increase employment of youth and women in the aquaculture sector The main objective was to increase aquaculture production by 10% and create 10,000 jobs. Other objectives included improving profitability for existing producers, securing employment for women fish retailers, expanding aquaculture in El Mineya and improving the policy environment for aquaculture.

Astaxanthin profiles and corresponding colour properties in Australian farmed black tiger prawn (Penaeus monodon) during frozen storage

The colour of commercial cooked black tiger prawns (Penaeus monodon) is a key quality requirement to ensure product is not rejected in wholesale markets. The colour, due to the carotenoid astaxanthin, can be impacted by frozen storage, but changes in colour or astaxanthin profile, during frozen storage, have not been studied in detail. Subsequently in this study, the aims were to define the astaxanthin (as cis, trans, mono-ester and di-ester forms) content, together with the colour properties, in both pleopods (legs) and abdominal segments. Changes in astaxanthin content and colour properties were further determined during frozen storage (−20°C). Total astaxanthin content was seen to decrease in all samples over time, with the rate of degradation being significantly greater (P < 0.05) in pleopods than abdomen. In both pleopods and abdomen, rate of degradation of esterified forms was significantly greater (P < 0.05) than non-esterified forms. Hue angle (increase), a* value (decrease) and L value (increase) were all seen to significantly change (P < 0.05) during storage, with changes being more prevalent in the pleopods. The pleopods are the key indicator of astaxanthin and colour loss in cooked black tiger prawns and preservation strategies are required to preserve astaxanthin and colour during frozen storage.

Processing traits of European catfish (Silurus glanis Linnaeus, 1758) from outdoor flow-through and indoor recycling aquaculture units

The quality of fish cultured using recycling units may differ from that of fish from outdoor farming units due to a range of deviating environmental determinants. This applies not only to flesh quality but also to morphological (processing) traits. This study evaluates processing yields of sibling fish cultured in two different farming units: (i) an outdoor pond aquaculture system with a flow-through regime (24.6 ± 0.2°C), and (ii) indoor tanks using a recirculation aquaculture system (RAS; 26.0 ± 1.0°C). Clear differences were observed in the most important processing traits, i.e. skinned trunk and fillet yields, which were both significantly higher (P < 0.01) in RAS fish due to significantly smaller (P < 0.05) head weight in fish of the flow-through system. Skin represented a significantly higher (P < 0.01) proportion of total weight in both RAS males and females. The most obvious difference was in the deposited fat weight, which was significantly higher (P < 0.01) in RAS fish. Visceral fat deposits were significantly higher (P < 0.01) in females and ventral and dorsal fat deposits higher (P > 0.05) in males.

Interaction between mercury (Hg), arsenic (As) and selenium (Se) affects the activity of glutathione S-transferase in breast milk: possible relationship with fish and shellfish intake

Breast milk is regarded as an ideal source of nutrients for the growth and development of neonates, but it can also be a potential source of pollutants. Mothers can be exposed to different contaminants as a result of their lifestyle and environmental pollution. Mercury (Hg) and arsenic (As) could adversely affect the development of fetal and neonatal nervous system. Some fish and shellfish are rich in selenium (Se), an essential trace element that forms part of several enzymes related to the detoxification process, including glutathione S-transferase (GST). The goal of this study was to determine the interaction between Hg, As and Se and analyze its effect on the activity of GST in breast milk. Milk samples were collected from women between day 7 and 10 postpartum. The GST activity was determined spectrophotometrically; total Hg, As and Se concentrations were measured by atomic absorption spectrometry. To explain the possible association of Hg, As and Se concentrations with GST activity in breast milk, generalized linear models were constructed. The model explained 44% of the GST activity measured in breast milk. The GLM suggests that GST activity was positively correlated with Hg, As and Se concentrations. The activity of the enzyme was also explained by the frequency of consumption of marine fish and shellfish in the diet of the breastfeeding women.

Vitamin A supplementation enhances Senegalese sole (Solea senegalensis) early juvenile’s immunocompetence: new insights on potential underlying pathways

Senegalese sole (Solea senegalensis) has been considered since the 1990´s to be a promising flatfish species for diversifying European marine aquaculture. However, pathogen outbreaks leading to high mortality rates can impair Senegalese sole commercial production at the weaning phase. Different approaches have been shown to improve fish immunocompetence; with this in mind the objective of the work described herein was to determine whether increased levels of dietary vitamin A (VA) improve the immune response in early juveniles of Senegalese sole. For this purpose, Senegalese sole were reared and fed with Artemia metanauplii containing increased levels of VA (37,000; 44,666; 82,666 and 203,000 total VA IU Kg-1) from 6 to 60 days post-hatch (early juvenile stage). After an induced bacterial infection with a 50 % lethal dose of Photobacterium damselae subsp. damselae, survival rate, as well as underlying gene expression of specific immune markers (C1inh, C3, C9, Lgals1, Hamp, LysC, Prdx1, Steap4 and Transf) were evaluated. Results showed that fish fed higher doses of dietary VA were more resistant to the bacterial challenge. The lower mortality was found to be related with differential expression of genes involved in the complement system and iron availability. We suggest that feeding metamorphosed Senegalese sole with 203,000 total VA IU Kg-1 might be an effective, inexpensive and environmentally friendly method to improve Senegalese sole immunocompetence, thereby improving survival of juveniles and reducing economic losses.

Bioremediation of phosphates in seawater: approach for recirculating marine aquaculture effluents

Marine Recirculating Aquaculture Systems (RAS) produce great volume of wastewater, which may be reutilized/recirculated or reutilized after undergoing different treatment/remediation methods, or partly discharged into neighbour water-bodies (DWW). Phosphates, in particular, are usually accumulated at high concentrations in DWW, both because its monitoring is not compulsory for fish production since it is not a limiting parameter, and also because there is no specific treatment so far developed to remove them, especially in what concerns saltwater effluents. As such, this work addresses two main scientific questions. One of them regards the understanding of the actual (bio)remediation methods applied to effluents produced in marine RAS, by identifying their advantages, drawbacks and gaps concerning their exploitation in saltwater effluents. The second one is the development of a new, innovative and efficient method for the treatment of saltwater effluents that potentially fulfil the gaps identified in the conventional treatments. Thereby, the aims of this thesis are: (i) to revise the conventional treatments targeting major contaminants in marine RAS effluents, with a particular focus on the bioremediation approaches already conducted for phosphates; (ii) to characterize and evaluate the potential of oyster-shell waste collected in Ria de Aveiro as a bioremediation agent of phosphates spiked into artificial saltwater, over different influencing factors (e.g., oyster-shell pre-treatment through calcination, particle size, adsorbent concentration). Despite the use of oyster-shells for phosphorous (P) removal has already been applied in freshwater, its biosorptive potential for P in saltwater was never evaluated, as far as I am aware. The results herein generated showed that NOS is mainly composed by carbonates, which are almost completely converted into lime (CaO) after calcination (COS). Such pre-treatment allowed obtaining a more reactive material for P removal, since higher removal percentages and adsorption capacity was observed for COS. Smaller particle size fractions for both NOS and COS samples also increased P removal. Kinetic models showed that NOS adsorption followed, simultaneously, Elovich and Intraparticle Difusion kinetic models, suggesting that P removal is both a diffusional and chemically rate-controlled process. The percentage of P removal by COS was not controlled by Intraparticle Diffusion and the Elovich model was the kinetic model that best fitted phosphate removal. This work demonstrated that waste oyster-shells, either NOS or COS, could be used as an effective biosorbent for P removal from seawater. Thereby, this biomaterial can sustain a cost-effective and eco-friendly bioremediation strategy with potential application in marine RAS.

Regenerative Aquaculture: Designing for Resilience of the Chesapeake Tidewater

The Chesapeake Bay is out of balance. As the effects of decades of overharvesting, overdevelopment, and pollution have taken their toll, tidewater communities are confronted with a loss of culture, livelihood, and the environment in which they live. This thesis seeks to reframe the problem of regeneration of community and environment, through the use of resilient design. Resilient design is the process of designing for an uncertain at risk future. Through resilient design, architecture and aquaculture can be combined with food culture to foster stewardship of place. This thesis will explore interconnectedness of tidewater food culture, the waterman culture, aquaculture, and regenerative design in an effort to generate a holistic solution. The final product will consist of a methodology of planning for resilience at a framework scale, and will also propose an architectural solution that combines educational facilities with commercial aquaculture, to foster stewardship and regeneration in the Chesapeake Tidewater.

Prevalence and characterization of Salmonella spp. in three shellfish-harvesting areas in France

Shellfish farming is an important economic activity in the Brittany and Normandy regions. However, a part of the production sites corresponds to relatively sensitive areas where the presence of faecal microorganisms is a major concern for shellfish and constitutes a possible health risk. Indeed, shellfish bioaccumulates in their tissues pathogenic contaminants present in water and can cause food-borne diseases such as salmonellosis. During a two-year study, we evaluated the presence of faecal indicators, measured the prevalence of Salmonella spp., isolated and characterized Salmonella spp. from three French shellfish-harvesting areas (shellfish and sediment) and their watersheds (from river water samples).

Seaweed Aquaculture and Marine Biotechnology

Macroscopic marine algae, typically known as macroalgae or seaweeds, form an important living resource of the oceans, as primary producers. People have collected seaweeds for food, both for humans and animals for millennia. They also have been a source of nutrient rich fertilizers, as well as a source of gelling agents known as phycocolloids. More recently macroalgae are playing significant roles in medicine and biotechnology. Although Biotechnology and in particular marine biotechnology may have different meanings for different people, under the present context we will consider a broader definition. Marine biotechnology consists on the use of biological knowledge and/or the application of biological techniques on marine organisms, for the development of products in some way beneficial for humans. Seaweed aquaculture is, therefore a biotechnology activity. It is also one that can allow for further development of the industry. Today, seaweed cultivation techniques are standardized, routine and economical. Several factors, including understanding the environmental regulation of life histories and asexual propagation of thalli, are responsible for the success of large-scale seaweed cultivation. Presently, seaweed aquaculture represents approximately 23% of the world’s aquaculture production, including fish, crustaceans and other animals. A promising approach for the development of seaweed aquaculture, and aquaculture in general, is the integrated multi-trophic aquaculture (IMTA). In these systems, fed-aquaculture is combined with extractive organisms like bivalves and/or algae. The constraints and advantages of IMTA will be discussed. In particular, land based IMTA systems allow for much greater environmental and input controls. Traceability, security of supply, high-quality standards and safety should be the future of seaweed aquaculture and contribute for the development of marine biotechnology.

Espèces de thonidés d'intérêt potentiel pour l'aquaculture en Méditerranée

Bluefin tuna is particularly concerned in the project of tuna rearing in the Mediterranean sea. However there are no reasons to neglect the other tuna species of the Mediterranean sea which present an interesting material for the development of the research on tuna cultivation.