FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Dentre as espÃcies produtoras de carragenana a Hypnea musciformis à a bastante comum na costa do nordeste Brasileiro. Embora as propriedades da carragenana da H. musciformis sejam promissoras, suas populaÃÃes naturais sÃo geralmente insuficientes a pressÃo da colheita comercial. O cultivo tem sido uma saÃda para incrementar a produÃÃo mundial de algas. Desta forma, o presente trabalho se propÃs a avaliar o potencial para aquicultura da carragenÃfita Hypnea musciformis (Wulfen) j.v. lamour. (Gigartinales - Rhodophyta). Os experimentos foram realizados na praia de Flecheiras, no litoral do estado do CearÃ, Brasil. Foi avaliado o cultivo da H. musciformis em estruturas long-line, o cultivo foi realizado em diferentes Ãpocas do ano (2007) com comprimentos de substratos variados, em diferentes profundidades, sendo avaliado ainda o rendimento da carragenana produzida por algas cultivadas. As mudas cultivadas obtiveram os melhores ganhos de biomassa apÃs 30, 45 e 60 dias de cultivo, para os meses de setembro à novembro 325,7Â44,2g; 359,4Â51,8g e 411,2Â77,8g respectivamente, com taxa de crescimento diÃrio 6,246%; 0,218% e 0,224% respectivamente. Em relaÃÃo à profundidade de cultivo, as algas apresentaram maior ganho biomassa a 0.2 m de profundidade, com taxas de crescimento diÃrio de 5,38 %. Para o comprimento do substrato de cultivo as cordas com 0,8 m apresentaram os melhores resultados, 403,33 g e 616,33g para 30 e 60 dias de cultivo respectivamente. O rendimento de carragenana nÃo apresentou diferenÃas significativas, sendo 32,96 (%) para as algas cultivadas e 32,74 (%) para algas dos bancos naturais / Among the species producing the carrageenan Hypnea musciformis is quite common on the northeast coast of Brazil. Although the properties of carrageenan from H. musciformis are promising, their natural populations are generally insufficient pressure from commercial harvest. The crop has been a way to increase the world production of algae. The present study was to evaluate the potential for aquaculture of Hypnea musciformis (Wulfen) jv Lamour. (Gigartinales - Rhodophyta). The experiments were carried on the Flecheiras beach on coast of CearÃ, Brazil. We evaluated the cultivation of H. musciformis in long-line structures, with adjustments as a substrate for the cultivation of this species, the culture was grown in different seasons (2007) substrates with varying lengths at different depths, and rated the performance of the carrageenan produced by grown algae. Seedlings grown obtained the best gains in biomass after 30, 45 and 60 days of cultivation, for the months of September to November 325.7  44.2 g, 359.4  51.8 g and 411.2  77.8 g respectively with daily growth rate 6.246%, 0.218% and 0.224% respectively. In relation to the depth of cultivation, the algae had greater average biomass to 0.2 meters deep, with daily growth rates of 5.38%. For the length of the growth substrate the strings with 0.8 meters showed the best results, 403.33 g and 616.33 g for 30 and 60 days culture respectively. The yield of carrageenan did not show significant differences, 32.96 (%) for algae grown and 32.74 (%) for algae from natural beds

Sea-bed benthic-invertebrate assemblages of species within and proximal to an existing mussel farm off Taniwhanui Point, eastern Waiheke Island, are reported. Substratum type, whether predominantly mud, gravels or an admixture of the two, mud/gravels, is shown to influence infaunal species assemblage composition; the bivalve Theora lubrica, ostracods, amphipods and polychaetes characterise muddy substrata; polychaetes, particularly spionids and syllids, ostracods, amphipods, bivalves and ophiuroids characterise mud/gravel substrata; and diverse assemblages of polychaetes, bivalves, pagurid crabs, gastropods, ostracods, ophiuroids and nemertean worms characterise gravel substrata. Significant differences in sea-bed assemblages are reported along one transect inside and outside the farm over the three seasons during which surveys were conducted, summer, autumn, winter of 2008. Along the northern side of the mussel farm those sediments beneath the farm are characterised by greater abundances of polychaetes and crustaceans (Malacostraca), whereas sediments outside the farm are characterised by greater abundances of bivalves and ostracods. Sediments both inside and outside the north-eastern border of the farm during summer are characterised by similar abundances of polychaetes, bivalves and ostracods. Similarly, those sediments within and outside the farm along its southern border during summer are characterised by abundances of polychaetes, bivalves, crustaceans (Malacostraca) and gastropods. Measures of relative abundance, rarity and species richness are applied to sea-bed assemblages off eastern Waiheke Island to enable an appraisal of the spatial distribution of each within and outside the farm, and throughout the eastern Waiheke Island region. One of these measures, relative abundance, is then compared with other, albeit limited abundance data from previous soft-sediment surveys conducted throughout Hauraki Gulf. The most species rich and abundant sites off eastern Waiheke Island occur in gravelly substrata between Waiheke Island and Pakatoa Island, and between Rotoroa and Ponui Islands, in addition to beneath the southern portion of the existing mussel farm. Gravel-based substrata are recognised to be the most species rich and densely populated with invertebrates for this sediment type in Hauraki Gulf. Similarly, the muddy substrata off eastern Waiheke Island region appear to host more individuals and species than any other reported muddy substratum in Hauraki Gulf. The existing mussel farm is shown to significantly affect sea-bed communities, but in a manner that has not been previously reported in New Zealand. Species richness and abundance are greater beneath the farm, as are the proportions of very rare and uncommon taxa to more common and ubiquitous taxa. Sediments beneath the farm are not characterised by elevated abundances and richness of opportunistic species; and no obvious difference in sediment grain size is apparent along a transect extending from 20 m inside the farm to at least 110 m outside it. The biological footprint of the farm is limited, appearing to extend no further than 20 metres from the northern physical boundary of the farm; the gross sedimentary characteristics (grain size) do not differ significantly within and outside the farm. Within and immediately outside the farm species richness and abundance tend to increase during colder seasons; beneath the farm, species richness (d), abundance (N), Shannon index (H’) and Simpson index (1-λ’) were higher during May (autumn) and August (winter) than during February (summer); diversity values outside the farm were similar during summer and autumn, but species richness (d), evenness (J’), Shannon index (H’) and Simpson index (1-λ’) were all greater during winter. No opportunistic taxa are considered to be appropriate indicators of organically enriched environments, at least enrichment that can be intuitively linked to any direct effect of the existing mussel farm. One species, the heart urchin Echinocardium cordatum, only rarely occurs inside the physical farm boundary, so its relative abundance renders it an appropriate indicator species of mussel-farm impacts.

This study focused on the optimisation of offshore marine fish-cage farming in Tenerife, Canary Islands. The main objective was to select the most suitable sites for offshore cage culture. This is a key factor in any aquaculture operation, affecting both success and sustainability. Moreover, it can solve conflicts between different coastal activities, making a rational use of the coastal space. Site selection was achieved by using Geographical Information Systems (GIS) based models and related technology, such as satellite images and Global Positioning System (GPS), to support the decision-making process. Three different cage systems were selected and proposed for different areas around Tenerife. Finally, a particulate waste distribution model (uneaten feed and faeces) was developed, also using GIS, for future prediction of the dispersive nature of selected sites. This can reduce the number of sites previously identified as most suitable, by predicting possible environmental impacts on the benthos if aquaculture was to be developed on a specific site. The framework for spatial multi-criteria decision analysis used in this study began with a recognition and definition of the decision problem. Subsequently, 31 production functions (factors and constraints) were identified, defined and subdivided into 8 sub-models. These sub-models were then integrated into a GIS database in the form of thematic layers and later scored for standardization. At this stage, the database was verified by field sampling to establish the quality of data used. The decision maker's preferences were incorporated into the decision model by assigning weights of relative importance to the evaluation under consideration. These, together with the thematic layers, were integrated by using Multi-criteria Evaluation (MCE) and simple overlays to provide an overall assessment of possible alternatives. Finally, sensitivity analysis was performed to determine the model robustness. The integration, manipulations and presentation of the results by means of GIS-based models in this sequential and logical flow of steps proved to be very effective for helping the decision-making process of site selection in study. On the whole, this study revealed the usefulness of GIS as an aquaculture planning and management tool. Cage systems that can withstand harsh environments were found to be suitable for use over a broader area of Tenerife's coastline. Thus, the more robust self-tensioned cage (SeaStation®) could be used over a greater area than the weaker gravity cages (Corelsa®). From the 228 km2 of available area for siting cages in the coastal regions with depth of 50 m, the suitable area (sum of scores 6, 7 and 8) for siting SeaStation® cages was 61 km2, while the suitable area for SeaStation® and Corelsa® cages was 49 and 37 km2 respectively. Most of the variation between these three cage systems was found among the intermediate suitability scores. It was concluded that the biggest differences in suitable area among cage systems are between Corelsa® and SeaStation® systems, followed by differences between Corelsa® and OceanSpar® cages, and OceanSpar® and SeaStation® respectively. This variability was mostly located on the N and NNW of the island, where waves, both long and short-term, are higher.

Sea-bed benthic-invertebrate assemblages of species within and proximal to an existing mussel farm off Taniwhanui Point, eastern Waiheke Island, are reported. Substratum type, whether predominantly mud, gravels or an admixture of the two, mud/gravels, is shown to influence infaunal species assemblage composition; the bivalve Theora lubrica, ostracods, amphipods and polychaetes characterise muddy substrata; polychaetes, particularly spionids and syllids, ostracods, amphipods, bivalves and ophiuroids characterise mud/gravel substrata; and diverse assemblages of polychaetes, bivalves, pagurid crabs, gastropods, ostracods, ophiuroids and nemertean worms characterise gravel substrata. Significant differences in sea-bed assemblages are reported along one transect inside and outside the farm over the three seasons during which surveys were conducted, summer, autumn, winter of 2008. Along the northern side of the mussel farm those sediments beneath the farm are characterised by greater abundances of polychaetes and crustaceans (Malacostraca), whereas sediments outside the farm are characterised by greater abundances of bivalves and ostracods. Sediments both inside and outside the north-eastern border of the farm during summer are characterised by similar abundances of polychaetes, bivalves and ostracods. Similarly, those sediments within and outside the farm along its southern border during summer are characterised by abundances of polychaetes, bivalves, crustaceans (Malacostraca) and gastropods. Measures of relative abundance, rarity and species richness are applied to sea-bed assemblages off eastern Waiheke Island to enable an appraisal of the spatial distribution of each within and outside the farm, and throughout the eastern Waiheke Island region. One of these measures, relative abundance, is then compared with other, albeit limited abundance data from previous soft-sediment surveys conducted throughout Hauraki Gulf. The most species rich and abundant sites off eastern Waiheke Island occur in gravelly substrata between Waiheke Island and Pakatoa Island, and between Rotoroa and Ponui Islands, in addition to beneath the southern portion of the existing mussel farm. Gravel-based substrata are recognised to be the most species rich and densely populated with invertebrates for this sediment type in Hauraki Gulf. Similarly, the muddy substrata off eastern Waiheke Island region appear to host more individuals and species than any other reported muddy substratum in Hauraki Gulf. The existing mussel farm is shown to significantly affect sea-bed communities, but in a manner that has not been previously reported in New Zealand. Species richness and abundance are greater beneath the farm, as are the proportions of very rare and uncommon taxa to more common and ubiquitous taxa. Sediments beneath the farm are not characterised by elevated abundances and richness of opportunistic species; and no obvious difference in sediment grain size is apparent along a transect extending from 20 m inside the farm to at least 110 m outside it. The biological footprint of the farm is limited, appearing to extend no further than 20 metres from the northern physical boundary of the farm; the gross sedimentary characteristics (grain size) do not differ significantly within and outside the farm. Within and immediately outside the farm species richness and abundance tend to increase during colder seasons; beneath the farm, species richness (d), abundance (N), Shannon index (H’) and Simpson index (1-λ’) were higher during May (autumn) and August (winter) than during February (summer); diversity values outside the farm were similar during summer and autumn, but species richness (d), evenness (J’), Shannon index (H’) and Simpson index (1-λ’) were all greater during winter. No opportunistic taxa are considered to be appropriate indicators of organically enriched environments, at least enrichment that can be intuitively linked to any direct effect of the existing mussel farm. One species, the heart urchin Echinocardium cordatum, only rarely occurs inside the physical farm boundary, so its relative abundance renders it an appropriate indicator species of mussel-farm impacts.

Thesis (M.Sc. (Ichthyology & Fisheries Science)) - Rhodes University, 2008.

Thesis (Ph. D.)--Rhodes University, 2004. / Title from PDF t.p. (viewed on May 2, 2006). Includes bibliographical references (p. 159-206).

A maricultura, ou mais especificamente a mitilicultura, tema deste trabalho, é uma das áreas da aquicultura que mais tem crescido nos últimos tempos. Muito embora possa ser praticada como atividade empresarial, vem se constituindo mais e mais como alternativa viável de geração de renda para pescadores artesanais profissionais e produtores individuais autônomos, devido ao baixo custo de implantação e manutenção, graças à extensa faixa litorânea e a condições climáticas ideais para o desenvolvimento desse tipo de atividade. Esta pesquisa objetivou proporcionar uma visão do estado atual da mitilicultura, notadamente na cidade de Ubatuba, Estado de São Paulo, Brasil, e investigar ações que possam promover o processo de forma financeiramente viável, de modo a tornar-se esta uma atividade geradora de trabalho e renda para as comunidades locais e colaborar com a diminuição da extração dos estoques pesqueiros. Especificamente, a pesquisa objetiva identificar as áreas produtivas, de acordo com a legislação vigente no Estado de São Paulo, caracterizar a mitilicultura implantada no município de Ubatuba e o perfil dos produtores, analisar economicamente o cultivo de mexilhões no município de Ubatuba. Foi realizado um estudo de caso sobre criação do mexilhão Perna perna, no qual se colheram dados por meio de entrevistas semi-estruturadas, sendo utilizada a abordagem qualitativa. A análise qualitativa dos dados utilizou a técnica da Análise de Conteúdo. A presente pesquisa mostra que a mitilicultura, como atividade geradora de trabalho e renda para as comunidades locais, pode ser estimulada no município de Ubatuba. Isto colaboraria para a diminuição da extração dos estoques pesqueiros, e o consequente impacto sobre o meio ambiente, aliado à geração de emprego e renda para as populações menos privilegiadas. / The mariculture, or more specifically the mitiliculture, theme of this investigastion, is one of the fastest growing areas of aquaculture in recent times, and although it can be practiced as a business activity, it is becoming more and more as a viable alternative for generating income for fishermen and professional autonomous individual producers due to the low cost of deployment and maintenance, thanks to the extensive coastline and ideal climate conditions for the development of this type of activity. This study aims to provide an overview of the current state of the mitiliculture, especially in the city of Ubatuba, State of Sao Paulo, Brazil, and to investigate actions that may promote the process in an financially available in order to become an activity that creates jobs and income for local communities and collaborate with the decrease in extraction of fish stocks. Specifically, the study attempts to identify productive areas, according to the law in the state of Sao Paulo, to describe mitiliculture deployed in Ubatuba and profiles of producers, and an economic analysis cultivation of mussels in Ubatuba. A case study was conducted on creation of the mussel Perna perna, in which data was collected through semi-structured interviews, and used the qualitative approach. The qualitative data analysis used the technique of content analysis. This research showed that the mitiliculture, as an activity which generates work and income for local communities, can be stimulated in Ubatuba. This would work to reduce the extraction of fish stocks, and the consequent impact on the environment, coupled with the generation of employment and income for the under-served.

The spotted grunter, Pomodasys commersonnii, has been identified as a candidate species for mariculture in South Africa due to its high market demand and apparent biological suitability for culture. In common with most other potential mariculture species the spotted grunter has an estuarine juvenile phase. In this respect, the difficulties encountered in determining the optimum environmental requirements of spotted grunter are applicable to the majority of other potential mariculture species. Due the variability of estuarine habitats determination of the optimum environmental requirements of estuarine species under laboratory conditions are a prerequisite to subsequent evaluation of aquaculture potential. Therefore, using the spotted grunter as a representative of a typical potent ial mariculture species, the aim of this study was to contribute to the protocol for evaluating the environmental requirements of potential aquaculture species. The growth of fish is dependent on the relationship between food intake, metabolism and environmental factors. In this relationship, environmental factors do not act on growth per se, but rather act through metabolism on growth. Consequently, the environmental factors affecting the growth of a fish species can be classified into functional categories according to their respective influence on metabolic processes. Five functional categories are recognised, namely: controlling, limiting, masking, directive and lethal factors. In this study, the functional categories were sequenced to develop a theoretical protocol for determining the optimum environmental requirements of potential mariculture species under artificial conditions. It was hypothesised that the correct sequence for experimentally determining the optimum environmental requirements of a species should correspond to theoretical protocol. The hypothesis was tested from the experimental investigation into the individual effects of temperature, salinity, light intensity, photoperiod and food intake on growth performance of juvenile spotted grunter. The investigations quantified the relative effects of controlling, masking, directive and limiting factors on growth performance. The results of the studies were statistically compared to obtain a ranking of the effects of the environmental factors (e.g. temperature, salinity, etc.) on growth performance of juvenile spotted grunter. The statistical ranking facilitated the formulation of a second protocol for sequentially determining the optimum environmental requirements of a species. The second protocol was derived purely from the experimental data. Based on the corroboration between the theoretical protocol and that formulated from the experimental investigations, the hypothesis was accepted. Confirmation of the protocol for examining the effects of controlling, limiting, masking and directive factors provided a basis for the development of a preliminary experimental sequence for determining the optimum environmental requirements of juvenile marine fish. In the development of the experimental sequence, the protocol was interpreted in conjunction with the experimental methods used to determine the effects of environmental factors on the growth of juvenile spotted grunter. The experimental sequence provides a logical frame work within which the optimum environmental requirements of other marine fish species can be determined. In addition, evaluation of growth performance by this method provides a basis for comparison of the mariculture potential between species.

Kappaphycus alvarezii (Doty) Doty ex P. C. Silva é uma alga vermelha comercialmente importante por ser a principal fonte de carragenana kappa, hidrocolóide utilizado como agente espessante e estabilizante em alimentos, fármacos e cosméticos. Devido à sua importância, é fundamental desenvolver bases tecnológicas visando sua maricultura sustentada e a seleção de linhagens mais produtivas com carragenanas de melhor qualidade. Esse trabalho teve como objetivos: 1. desenvolver a cultura de tecidos para a propagação de plantas matrizes, selecionar as melhores linhagens para cultivo in vitro e produzir novas linhagens; 2. testar a espécie como biofiltro em cultivos integrados com peixes e 3. analisar os efeitos de diferentes condições de cultivo no rendimento e na qualidade das carragenanas, segundo parâmetros comerciais. Para o primeiro objetivo, foram testadas cinco linhagens (tetrasporófitos marrom, verde e vermelho, gametófito feminino e linhagem “Edison de Paula”, EP, selecionada a partir da germinação de tetrásporos) para definir o sistema experimental mais adequado para a micropropagação. Explantes da linhagem EP foram tratados com colchicina com a finalidade de induzir linhagens poliplóides. Essa linhagem foi selecionada por apresentar maior tolerância aos procedimentos de esterilização utilizados na cultura de tecidos. Apesar das altas taxas de indução de calos observadas em todas as linhagens, a regeneração de talos a partir dos calos (regeneração indireta) foi difícil. A regeneração de talos a partir dos explantes (regeneração direta) foi estimulada pela utilização de fitorreguladores e da colchicina. A contaminação dos cultivos por uma espécie filamentosa Acrochaetium no talo da linhagem EP foi inibida com a adição de 90 mM de glicerol. A formação de novas linhagens poliplóides através da utilização de colchicina não foi demonstrada. Os resultados indicaram que é possível utilizar a micropropagação através da produção de explantes para manutenção de um estoque de plantas matrizes de diferentes linhagens em laboratório. Para o segundo objetivo, o tetrasporófito marrom da espécie foi cultivado em tanques com água do mar e com efluente da criação de peixes da espécie Trachinotus carolinus (pampos) por 10 dias. As taxas de crescimento das algas cultivadas nos tanques foram mais baixas que às obtidas em cultivo no mar. Os valores máximos da taxa de remoção nos efluentes foram: NO3- = 18,2%; NO2- = 50,8%; NH4+ = 70,5% e PO43- =26,8%, nas condições testadas. Todas as plantas sobreviveram até o final do período experimental, mas apresentaram sinais de "ice-ice", doença associada ao estresse fisiológico. Diferenças entre os rendimentos de carragenana de algas cultivadas em água do mar ou em efluente de criação de peixes não foram significativas. Esses resultados demonstraram que é possível utilizar K. alvarezii como biofiltro de águas eutrofizadas derivadas da criação de peixes embora a espécie seja típica de águas oligotróficas. Para o terceiro objetivo, o gametófito feminino foi cultivado em balsas flutuantes segundo diferentes condições de cultivo (período de cultivo, profundidade e densidade do plantio). As carragenanas das plantas cultivadas nesses tratamentos foram extraídas e algumas propriedades foram determinadas. As taxas de crescimento variaram de 5,2 a 7,2% dia-1, com as maiores taxas obtidas em 28 dias de cultivo, em profundidade de 0 e 0,5 m e densidade do plantio de 12 e 8,4 plantas m-2. As condições de cultivo que forneceram melhor carragenana, segundo padrões comerciais foram: 45 dias de cultivo, na superfície, com densidade de 12 plantas m-2. Considerando que esse cultivo foi realizado na estação menos favorável do ano (inverno) para o crescimento das plantas, esses resultados indicam que o local onde a espécie foi introduzida é adequado para a implementação do cultivo comercial. Através dos resultados obtidos nesse trabalho, desejamos contribuir com a maricultura sustentável de uma espécie promissora no Brasil, com excelente potencial econômico reconhecido mundialmente, além de deixar algumas sugestões e propostas para novos estudos. / Kappaphycus alvarezii (Doty) Doty ex P. C. Silva is a red seaweed commercially important for being the main source of kappa carrageenan, hydrocolloid utilised as thickener and stabiliser in foods, medicaments and cosmetics. Due to its importance it is fundamental to develop technological bases on purpose of its sustainable mariculture and the selection of more productive strains with best qualities carrageenans. The objectives of this work were: 1. to develop the tissue culture for micropropagation of matrix plants, to select the better strains for in vitro culture and to produce new strains; 2. to test the species as biofilter in integrated cultivation with fishes and 3. to analyse the effects of different cultivation conditions in carrageenan yield and quality, according to commercial parameters. For the first objective, five strains (brown, green and red tetrasporophytes, female gametophyte and "Edison de Paula" strain, EP, selected from tetraspores progeny) were tested to define the experimental system suitable for micropropagation. Explants from EP strain were treated with colchicine with the aim of induce polyploid strains. This strain was selected by presenting high tolerance to sterilization procedures used in tissue culture. Despite the high rates of callus induction observed in all strains, thallus regeneration from callus (indirect regeneration) was difficult. Thallus regeneration from explants (direct regeneration) was stimulated by phytorregulators and colchicine. The culture contamination by a filamentous species Acrochaetium in the tallus of EP strain was inhibited with addition of 90 mM glycerol. The formation of polyploid strains by colchicine treatments was not proved. The results indicated that it is possible to use the micropropagation through the production of explants for maintaining matrix plants stocks from different strains in laboratory. For the second objective, the brown tetrasporophyte was cultivated in tanks with seawater and with effluents of the fish Trachinotus carolinus (pampos) rearing for 10 days. Growth rates of seaweeds cultivated in tanks was lower than those cultivated in the sea. The maximum values of removal rates from the effluents were: NO3- = 18.2%; NO2- = 50.8%; NH4+ = 70.5% and PO43- =26.8% in the conditions tested. All plants survived until the end of experimental period, but they presented signals of "ice-ice", disease associated to physiological stress. Differences between the carrageenan yields from plants cultivated in seawater and in effluents of fish rearing were not significant. These results showed that it was possible utilised the seaweed K. alvarezii as biofilter in effluents from fish rearing, although the species is typical of oligotrophic waters. For the third objective, the female gametophyte was cultivated from floating raft according to different cultivation conditions (i.e. cultivation period, depth and planting density). Carrageenan from the plants cultivated under these treatments was extracted and some properties were determined. Growth rates ranged from 5.2 to 7.2% day-1, with the higher rates obtained in 28 day cultivation period, at 0 and 0.5 m of depth and planting density of 12 and 8.4 plants m-2. The cultivation conditions that supplied the best carrageenan, according to commercial patterns were: 45 days of cultivation, in surface, with planting density of 12 plants m-2. Considering that this cultivation was conducted in the unfavourable season of the year (winter) for the growth of K. alvarezii, the results indicated that the site where the species was introduced is adequate to the implementation of commercial cultivation. Through the results obtained in this work, we wish to contribute with sustainable mariculture of a successful species in Brazil, with excellent economic potential recognised in all world, besides leave some suggestions and proposes for new studies.

Growth. mortality. production. physiology and seasonal cycles of condition index and proximate biochemical composition of experimental populations of blue mussels (Mytilus edulis L.) were studied at different sites in Loch Etive and Loch Leven on the West coast of Scotland between May 1990 and September 1992. The main objective of the study was to evaluate current suspended mussel culture practices and to establish the basis for their possible integrated cultivation with salmon cage fanning. In addition. a preliminary investigation on employment of the . Charm IT' system as a rapid method for detecting residues of drugs used for treating cultured salmon in the tissues of mussels was carried out. There were some differences between sites in salinity, seston and particulate organic matter, but not in chlorophyll-a. Food availability (as particulate organic matter and chlorophyll-a) showed a clear seasonal cycle and in consequence growth of mussels were relatively rapid from late-spring until mid-autumn (g 6 months) and very slow or absent during the rest of the year. This period of rapid length and tissue growth coincided with relatively optimum environmental conditions and there were apparent positive relationships between monthly growth rates and temperature and chlorophyll-a values, indicating the limiting effect of these two primary factors on growth during autumn-winter and even in early spring. Almost all growth parameters examined were showed significant differences between the lochs. Growth performance of both native and transplanted mussels in Loch Leven was quite poor. Overall annual length increments were 25.1-25.9 mm at sites in Loch Etive and Dunstaffnage Bay, but 20.1-22.8 mm in Loch Leven. A crosstransplantation experiment showed that site rather than stock is the main reason for differences in growth parameters between Lochs Etive and Leven. These observed growth differences between sites and stocks were also confirmed by physiological measurements and estimated growth potential or scope for growth. Growth of mussels at salmon farms was faster than at neighbouring mussel farms during two annual experiments, but only meat weight at one salmon farm during experiment I, and length and live weight at the salmon farm in Loch Etive as well as all growth parameters at the salmon fann in Loch Leven during experiment II were significantly greater (}>sO.05). These differences were most likely a result of high particulate organic matter levels at salmon fanns. Similar to growth, biomass and production, the condition index and biochemical composition of mussels showed a clear seasonal cycle. Meat content, condition index and glycogen values were high during summer, started to decline in late autumn and reached minimum values in April before showing maximum increases in May. This reflects the typical storage and reproductive cycle of mussels in Northern Europe: accumulation of reserves during summer and their utilization during winter and early spring as energy resources for metabolism and reproduction. This cycle clearly showed that the main spawning of mussels on the West coast of Scotland occurred during March-May, and primary spat settlement from June to August. Heavy losses occurred from French socks, causing substantial amounts of eliminated biomass during experiment I, but when these fall outs were eliminated during experiment II by using lantern nets, it was clear that natural mortality rates were quite low and similar at all sites. Apart from growth characteristics and physiological responses, there were persistent morphological differences between the Loch Etive and Loch Leven populations. Cross-transplantation and physiological measurements after various acclimatization periods showed that, while morphological differences might be related to genetic origin, all other differences between the two popUlations are governed by environmental factors. The practical implications of these findings for developing suspended mussel culture on the West coast of Scotland and the possibility of a simple integrated salmon-mussel fanning system, which could be effective in controlling potential eutrophication from intensive salmon cage fanning and the removing large amounts of organic matter by mussels leading alterations in ecosystem, are discussed. A preliminary study with the Chann II Test has showed that the system is not so appropriate method as expected for screening mussel tissue sampled straight from the field, since mussel tissues require purification due to interference from bacteria or microbial detritus, before screening.