Concern for possible environmental damage constrains development of the aquaculture
industry in the United States. Potential environmental interactions, including degradation
of water quality, introduction of exotic species, pollution of the seafloor, adverse interaction
with the seafloor benthic community, adverse interactions with protected species, and genetic interactions of potential escapees are all generally viewed as negative interactions, and thus are of substantial concern to the public and to regulators. Certainly, the culture of finfish in cages can be detrimental to the local water quality and the benthos beneath the cages when the fish are overfed or when too many production units are located in an area of limited carrying capacity or restricted circulation, as has been demonstrated by numerous published reports (see Black 2001 for a summary).
Digital library
-
-
The United States has a small net-pen salmon industry dating back over 40 years and a nascent net-pen industry for other marine fish. The United States net-pen aquaculture sector has improved its resource efficiency in terms of the amount of fish meal and fish oil used in feeds and reduced its environmental impacts in terms of the mass loading and impact of nutrient discharge on the receiving ecosystem, the incidence and treatment of fish diseases, the use of antibiotics, and the number and impact of fish escapes, while increasing production. These changes can be attributed to a combination of advances in science and technology, rising cost of fish meal/oil, improved management, and informed regulatory practices. Net-pen aquaculture has become an efficient food production system. Existing laws and regulations in the United States effectively address most of the potential adverse environmental effects of net-pen aquaculture.
-
Finfish aquaculture in Australia is presently dominated by two species: Thunnus maccoyii (southern bluefin tuna) in South Australia and Salmo salar (Atlantic salmon) in Tasmania.
Other species farmed include yellowtail kingfish (Seriola lalandi), snapper (Pagrus auratus), and barramundi (Lates calcarifer) with others, such as striped trumpeter (Latris lineata) and mulloway (Argyromonas holoepidotus), in development. The finfish industry in Australia is comparatively small by world standards, but in the regional areas where the farms are located, it contributes hundreds of millions of dollars to the local economy (Table 1). Southern bluefin tuna (SBT) farming is unusual in that it relies on farming fish that have been obtained from wild capture of a quota-limited stock subject to international regulation. -
Culture studies have been carried out on a local population of the agar-producing red seaweed Graci/aria verrucosa to ascertain the optimum range of environmental factors for growth, with a view to potential mariculture. The plants grew well at 15 - 25°C, poorly at cooler temperatures, and did not survive 30°C. Despite little salinity variation in the natural habitat, the population was shown to be euryhaline, with reasonable growth from 9 to 45%0 salinity, although plants grew maximally around the salinity of full seawater. An irradiance of 80 fl.mol m-2 S-l was sufficient for maximal growth, and growth was not severely reduced at 850 fl.mol m-2 S-l (the highest experimental irradiance). Agar content was 32 - 34% of the dry weight, and this level was not significantly affected by 4 weeks' growth at various temperatures.
Kultuurstudies is uitgevoer op 'n inheemse populasie van die agar-produserende rooi seewier Graci/aria verrucosa om die optimale bereik te bepaal van omgewingsfaktore wat die groei be·fnvloed, met die oog op moontlike marikultuur. Plante groei goed tussen 15 en 25°C, swak by laer temperature, en hulle oorleef nie 30°C nie. Ondanks min skommelinge in die soutgehalte van die natuurlike omgewing, blyk die populasie eurihalien te wees, met 'n redelike groei tussen 9 en 45%0 soutgehalte, alhoewel plante maksimaal gegroei het by 'n soutgehalte rondom die van normale seewater. 'n Beligting van 80 fl.mol m-2 S-l is voldoende om optimale groei te bewerkstellig, terwyl groei nie ernstig afgeneem het by 250 fl.mol m-2 S-l (die hoogste eksperimenteel toegepaste beligting) nie. Die agargehalte bedra 32 - 34% van die droe gewig, en hierdie waarde is nie beduidend be·fnvloed deur vier weke se groei by verskillende temperature nie.
-
Culture studies have been carried out on a local population of the agar-producing red seaweed Graci/aria verrucosa to ascertain the optimum range of environmental factors for growth, with a view to potential mariculture. The plants grew well at 15 - 25°C, poorly at cooler temperatures, and did not survive 30°C. Despite little salinity variation in the natural habitat, the population was shown to be euryhaline, with reasonable growth from 9 to 45%0 salinity, although plants grew maximally around the salinity of full seawater. An irradiance of 80 fl.mol m-2 S-l was sufficient for maximal growth, and growth was not severely reduced at 850 fl.mol m-2 S-l (the highest experimental irradiance). Agar content was 32 - 34% of the dry weight, and this level was not significantly affected by 4 weeks' growth at various temperatures.
Kultuurstudies is uitgevoer op 'n inheemse populasie van die agar-produserende rooi seewier Graci/aria verrucosa om die optimale bereik te bepaal van omgewingsfaktore wat die groei be·fnvloed, met die oog op moontlike marikultuur. Plante groei goed tussen 15 en 25°C, swak by laer temperature, en hulle oorleef nie 30°C nie. Ondanks min skommelinge in die soutgehalte van die natuurlike omgewing, blyk die populasie eurihalien te wees, met 'n redelike groei tussen 9 en 45%0 soutgehalte, alhoewel plante maksimaal gegroei het by 'n soutgehalte rondom die van normale seewater. 'n Beligting van 80 fl.mol m-2 S-l is voldoende om optimale groei te bewerkstellig, terwyl groei nie ernstig afgeneem het by 250 fl.mol m-2 S-l (die hoogste eksperimenteel toegepaste beligting) nie. Die agargehalte bedra 32 - 34% van die droe gewig, en hierdie waarde is nie beduidend be·fnvloed deur vier weke se groei by verskillende temperature nie.
-
Fermentation and enzyme-assisted extraction (EAE) improve nutritional and functional properties of foods by increasing the extraction of active compounds, ingestion rates, and body absorption. In this study, we investigated whether applying the EAE process improves the extraction and isolation efficiency of a polysaccharide from fermented Ecklonia cava (FE), which inhibited NO production in lipopolysaccharide (LPS)-activated RAW 264.7 cells. The results showed that the FE using the fungi Candida utilis and two different bacteria, namely Lactobacillus brevis and Saccharomyces cerevisiae increased protein and carbohydrate contents in comparison with those in non-fermented E. cava (NE). Aqueous extracts of fermented E. cava increased extraction yields and carbohydrate content, compared with the aqueous extract of NE. In addition, treating LPS-stimulated RAW 264.7 cells with aqueous extracts resulted in reduced NO production compared to that in LPS-treated cells. Ten EAEs of L. brevis-fermented E. cava (LFE) improved NO inhibitory effects in LPS-activated RAW 264.7 cells and the Viscozyme extract (VLFE) from the resulting extracts showed the highest NO inhibitory effect. We found that the >30 kDa fraction of VLFE led to markedly high inhibition of LPS-induced NO production as compared to that in the 30 kDa fraction (VLFEP) consisted of fucose and markedly decreased NO production induced by LPS stimulation. VLFEP could be useful as an anti-inflammatory agent to suppress macrophage activation.
-
A fundamental investigation of the biosorption of Cd2+from aqueous solution by the edible seaweedSargassum fusiformewas performed under batch conditions. The influences of experimental parameters, such as the initial pH, sorption time,temperature, and initial Cd2+concentration, on Cd2+uptake byS. fusiformewere evaluated. The results indicated that thebiosorption of Cd2+depended on the initial Cd2+concentration, as well as the pH. The uptake of Cd2+could be described bythe Langmuir isotherm model, and both the Langmuir biosorption equilibrium constant and the maximum biosorptioncapacity of the monolayer decreased with increasing temperature, thereby confirming the exothermic character of thesorption process. The biosorption kinetics follows the pseudo-second-order kinetic model, and intraparticle diffusion is thesole rate-limiting step for the entire biosorption period. These fundamental equilibrium and kinetic results can supportfurther studies to the removal of cadmium fromS. fusiformeharvested from cadmium-polluted waters.
-
Sea ranching of sandfish is being piloted as a means to enhance the recovery of depleted natural stocks and provide a supplemental source of income for artisanal fishers. Participatory and adaptive approaches were employed in the establishment and management of sea ranches to ensure that benefits accrue to both the ‘rights-holders’ and other community members. Three pilot sea-ranching sites have been established in north-western Luzon, the Philippines. The sites are managed by members of a local association of small fishers with the support of the municipal government, which granted limited exclusive-use rights to the sea-ranch managers. Each site was delineated into two major use zones: the 1-ha no-take release and nursery area, and the 4-ha reserve area. Multiple releases of cultured sandfish juveniles produced from local wild broodstock were conducted in the sites. Within 7–10 months, effective spawning populations were established in the sea-ranching sites when the density of reproductively mature (>200 g) individuals (ind) exceeded 100 ind/ha. Growth and survival rates were variable among sites. At the Bolinao sea ranch, the maximum estimated overall density reached 1,119 ind/ha, with an estimated survival rate of 39% after 19 months. Mass spawning of sandfish in the sea ranch further demonstrated that community-based sandfish sea ranching can help rebuild depleted wild populations. Among the major threats to sustainability are periodic poaching and storms, which reduce harvestable biomass and economic returns to the rights-holders. Sea ranching should be integrated within a broader fishery management framework to improve the management of sea cucumber fisheries.
-
The amount of macroalgal biomass is an important ecosystem variable. Estimates can be made for a sampled area or values can be extrapolated to represent biomass over a larger region. Typically biomass is scaled-up using the area multiplied by the mean: a non-spatial method. Where algal biomass is patchy or shows gradients, non-spatial estimates for an area may be improved by spatial interpolation. A separate issue with scaling-up biomass estimates is that conventional confidence intervals based on the standard error (SE) of the sample may not be appropriate. The issues around interpolation and confidence intervals were examined for three fucoid species using data from 40 × 0.25 m-2 quadrats thrown in a 0.717 ha sampling plot on the shore of Galway Bay. Despite evidence of spatial autocorrelation, interpolation did not appear to improve estimates of the total plot biomass of Fucus serratus and F. vesiculosus. In contrast, interpolated estimates for Ascophyllum nodosum had less error than those based on the non-spatial method. Bootstrapped confidence intervals had several benefits over those based on the SE. These benefits include the avoidance of negative confidence limits at low sample sizes and no assumptions of normality in the data. If there is reason to expect strong patchiness or a gradient of biomass in the area of interest, interpolation is likely to produce more accurate estimates of biomass than non-spatial methods. Development of methodologies for biomass would benefit from more definition of local and regional gradients in biomass and their associated covariates.
-
Oito carragenófitas, da costa portuguesa, representando sete géneros e quatro famílias das Gigartinales, foram estudadas na baía de Buarcos durante cerca de um ano (estudo da variações sazonais) e em quinze estações costeiras (estudo das variações geográficas), localizadas entre o Baleal (Peniche), na zona Centro, e Moledo, na zona Norte. A determinação da variação sazonal e geográfica do estado reprodutor, comprimento, peso seco e conteúdo em carragenana, foi feita com base no método de amostragem aleatória. Em geral, o comprimento e a biomassa das carragenófitas estudadas apresentam variações sazonais, com um incremento no início da Primavera (Abril), um aumento acentuado no início do Verão (Junho/Julho) e valores reduzidos no final do Verão, Outono e Inverno. O baixo conteúdo em colóide registado no Inverno (Dezembro) e, em oposição, o elevado teor em carragenana verificado nas amostras colhidas no Verão (Julho), podem estar relacionados, respectivamente, com os elevados e reduzidos níveis de nutrientes (Azoto e Fósforo) presentes na água. O maior conteúdo médio em carragenana foi registado numa amostra de Chondracanthus acicularis (40.1 %), seguido dos valores registados nas amostras de Gigartina pistillata (38.7 %) e Chondracanthus teedei var. lusitanicus (34.9 %). O método de amostragem aleatória (com quadrados) foi usado na determinação da biomassa e o método de “amostragem em contínuo sobre um transepto” no cálculo da percentagem de cobertura de cada carragenófita, em dois períodos: Outono/Inverno e Primavera/Verão. As carragenófitas com maior cobertura e biomassa foram as seguintes: Chondrus crispus (3.75 % - 570 g m -2); C. acicularis (3.45 % - 99 g m-2); C. teedei var. lusitanicus (2.51 % - 208 g m-2); Mastocarpus stellatus (2.02 % - 520 g m-2).
Para a caracterização dos diferentes tipos de carragenana foram usadas as técnicas espectroscópicas: FTIR-ATR, FT-Raman, 1H e 13C-RMN. Com base nestas técnicas, nomeadamente em FTIR-ATR e FT-Raman, foram desenvolvidas metodologias inovadoras que nos permitiram a correcta identificação das diversas fracções de carragenana, em particular das variantes da família lambda (carragenana lambda, ksi e theta) e dos precursores biológicos (mu e nu) das carragenanas gelificantes (kappa e iota, respectivamente). Visto que as amostras foram sujeitas a uma manipulação mínima (as algas são simplesmente secas e moídas), a composição determinada representa, o mais fielmente possível, a composição natural dos ficocolóides. Nas análises espectroscópicas foram usados, como referência, os espectros de amostras comerciais de carragenana e de carragenófitas utilizadas com fins industriais. A espectroscopia de ressonância magnética nuclear do protão e do carbono 13 foi usada na caracterização e quantificação dos diferentes componentes das carragenanas extraídas (extracção aquosa e alcalina). De acordo com as recomendações da IUPAC foi apresentado, relativamente ao DSS como standard interno, um novo conjunto de deslocamentos químicos de 1H e 13C-RMN dos principais tipos de carragenana. Além disso, foram reportados os deslocamentos químicos relativos ao ácido pirúvico e ao amido florídeo, compostos que surgem normalmente associados às carragenanas.
Relativamente aos diferentes tipos de carragenana produzidos pelas espécies estudadas, devem ser realçados os seguintes resultados: os gametófitos femininos e talos não frutificados do C. crispus, M. stellatus. C. teedei var. lusitanicus, G. pistillata e C. acicularis produzem carragenanas híbridas com diferentes rácios kappa/iota (copolímeros de carragenana kappa/iota); O G. crenulatus e o A. devoniensis produzem uma grande diversidade de híbridos, com diferentes rácios kappa/iota, dependentes de variações sazonais; as carragenanas da família lambda estão presentes nos tetrasporófitos de C. crispus (carragenana lambda), M. stellatus (carragenana lambda), C. teedei var. lusitanicus (carragenana híbrida ksi/theta), C. acicularis (carragenana híbrida ksi/theta) e G. pistillata (carragenana híbrida ksi/lambda); as diferentes gerações do Calliblepharis jubata produzem carragenana do tipo iota.
Com base nos nossos resultados, baseados em FTIR-ATR, FT-Raman e 1HRMN, muito mais sensíveis do que a 13C-RMN, podemos concluir que a carragenana kappa e iota têm precursores biológicos distintos, respectivamente mu e nu.
O método de extracção laboratorial alcalino, usado neste trabalho, possibilita a extracção de carragenanas com baixo índice de degradação e elevado peso molecular, vindo confirmar a ideia de que a extracção de ficocolóides, mesmo em condições “suaves”, possibilita a ciclização das suas unidades constituintes.
A combinação de uma grande cobertura, de uma elevada biomassa disponível e um elevado teor em carragenana das espécies pertencentes ao género Chondracanthus e de Gigartina pistillata, permite-nos considerar que estas carragenófitas constituem uma potencial fonte industrial de copolímeros de carragenana kappa/iota, em adição às carragenófitas tradicionalmente colhidas em Portugal (C. crispus e M. stellatus). No entanto, atendendo a que na actividade de apanha de algas marinhas, em populações selvagens existentes no patamar médiolitoral, existe o risco de sobre-colheita e subsequente perda económica, para além da redução ou até destruição da biodiversidade algal, é necessário desenvolver estudos com vista à inclusão destas carragenófitas em sistemas integrados de aquacultura.
Em diversas estações costeiras encontrámos talos heterospóricos de G. pistillata (contendo, simultaneamente, soros de tetrasporocistos e cistocarpos), os quais foram objecto de estudos morfológicos, citológicos e bioquímicos. Estes estudos foram alargados a outras carragenófitas seleccionadas, o que nos permitiu analisar alguns aspectos da carposporogénese, tetrasporogénese (C. teedei var. lusitanicus) e distribuição dos polissacarídeos (celulose e carragenana) nos talos e paredes celulares (G. crenulatus, A. devoniensis e G. pistillata)
Pages
Marine Agronomy Group, CAFNRM, UH-Hilo
200 W. Kawili st., HI 96720, USA
Contact: Marine.Agronomy.Group@gmail.com
Funding for this web portal is provided by the World Wildlife Fund and the University of Hawaii-Hilo.