Determination of physical behaviour of feed pellets in Mediterranean water

Vassallo, Paolo; Doglioli, Andrea M.; Rinaldi, Fabrizio; Beiso, Ilaria

doi:10.1111/j.1365-2109.2005.01403.x

Cited by 27 publications

(29 citation statements)

References 14 publications

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“…Differences in fish abundance and species composition recorded at the SB and ABT farms may be related to the type of food used and/or the type of habitat at each farm. Whole baitfish differ substantially in their nutrient composition, food size and settling velocity from the food pellets used at SB farms (Vassallo et al 2006). Šegvić Bubić et al (2011) suggested that the pellets and their fine particulates may attract a more diverse fish community and can be more easily consumed than baitfish.…”

Section: Discussionmentioning

confidence: 99%

Spatial and temporal extension of wild fish aggregations at Sparus aurata and Thunnus thynnus farms in the north-western Mediterranean

Bacher¹,

Gordoa²,

Sagué³

2012

Aquacult. Environ. Interact.

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Fish farms cause wild fish to aggregate nearby and thus act to modify their distribution, but the spatial and temporal extent of the attraction effect around farms is still poorly understood. We examined attraction using an integrated approach combining 3 factors: spatial extent, depth and season. We analysed an Atlantic bluefin tuna Thunnus thynnus (ABT) and a gilthead seabream Sparus aurata (SB) farm off the north-eastern coast of Spain which represent different fish farming models in the Mediterranean. Underwater visual counts were conducted from summer 2010 to spring 2011. We recorded 39 species at the SB farm and 17 species at the ABT farm. The analysis of fish abundance and biomass at 3 stations located along a distance gradient from the farm (SB: 0, 30, 200 m; ABT: 0, 100, 200 m) showed significantly higher values next to the cages than at more distant stations, revealing that the spatial extent of the attraction effect was mainly restricted to the cage rather than following a gradient. The intensity of the cage effect varied according to farm, season and depth, reflecting species-specific behaviours. At the SB farm, the cage effect persisted year round, varying with depth, whereas at the ABT farm, the effect was only detected in summer and spring. These distinct spatial and temporal aggregation patterns suggest that implementation of fishery regulatory measures to protect wild fish should be farm-specific. This study emphasizes the importance of using an integrated approach to study wild fish aggregations at farms.

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Section: Discussionmentioning

confidence: 99%

Spatial and temporal extension of wild fish aggregations at Sparus aurata and Thunnus thynnus farms in the north-western Mediterranean

Bacher¹,

Gordoa²,

Sagué³

2012

Aquacult. Environ. Interact.

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“…Cage aquaculture can release a considerable amount of biogenic waste such as organic wastes and inorganic nutrients that are generated in the production process (Troell & Norberg 1998, Cheshuk et al 2003, Vassallo et al 2006, Redmond et al 2010. The rapid expansion of cage aquaculture has raised a general concern about increasing amounts of solid and dissolved nutrients released to the aquatic environment (Perez 2002, Whitmarsh et al 2006, Redmond et al 2010, Azevedo et al 2011, Skriptsova & Miroshnikova 2011.…”

Section: Introductionmentioning

confidence: 99%

Discharge of nutrient wastes from salmon farms: environmental effects, and potential for integrated multi-trophic aquaculture

Wang¹,

Olsen²,

Reitan³

et al. 2012

Aquacult. Environ. Interact.

208

144

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We quantified release rates of carbon (C), nitrogen (N) and phosphorus (P) waste from Norwegian salmon farms in 2009 in order to evaluate the theoretical environmental influence on surrounding waters and the potential for integrated multi-trophic aquaculture (IMTA) driven by salmon aquaculture. Of the total feed input, 70% C, 62% N and 70% P were released into the environment, equivalent to an annual discharge of about 404 000, 50 600 and 9400 t of C, N and P, respectively, based on total salmon production of 1.02 × 10 6 t. We predicted that 48% of feed C was respired as CO 2 , 45% of feed N was excreted as dissolved inorganic N (DIN), and 18% of feed P was excreted as dissolved inorganic P (DIP). Approximately 44% of feed P was released as particles, dominating solid wastes. The mean food conversion ratio (feed supplied per fish produced) of Norwegian salmon farms was 1.16 ± 0.08 SE in 2009. Estimates of the potential for IMTA driven by salmon farming showed a far higher potential for seaweed production based on the released DIN than for mussel production based on released appropriately sized particulate organic carbon (POC). The daily volumetric loading rates of DIN from salmon farms (range for counties: 40 to 501 µg N m −3 d −1 ) were <15% of the natural loading rate of nitrate from deep water, suggesting that the nutrient loading rate is within safe limits.KEY WORDS: Cage aquaculture · Atlantic salmon · Nutrient wastes · Feed conversion ratio · FCR · Integrated multi-trophic aquaculture · IMTA · Seaweed · Blue mussels Resale or republication not permitted without written consent of the publisher

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“…Estos coeficientes fueron corregidos bajo el supuesto de que aproximadamente un 5% del alimento introducido a las jaulas no es consumido por los peces. Este porcentaje es considerado como un valor típico para el alimento no consumido (Vassallo et al 2006), aunque en la actualidad este porcentaje puede variar de valores más pequeños para piscifactorías de salmón Atlántico altamente tecnificadas hasta 20% para piscifactorías más pequeñas y con menos tecnología.…”

Section: Caracterización De Los Residuos De La Piscifactoríaunclassified

“…Las partículas de alimento no consumido caen aproximadamente 3 veces más rápido que las partículas fecales (Gowen et al 1989), pues las velocidades de sedimentación son entre 6 y 14 cm s -1 para partículas de alimento (Panchang et al 1997, Doglioli et al 2004, Vassallo et al 2006, Piedecausa et al 2009), y entre 0.05 y 7.5 cm s -1 para partículas fecales (Panchang et al 1997, Doglioli et al 2004, Piedecausa et al 2009). Con base en estos estudios, las velocidades de sedimentación consideradas en este documento…”

Section: Caracterización De Los Residuos De La Piscifactoríaunclassified

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Modeling the benthic loading of particulate wastes from a gilthead seabream (Sparus aurata) farm during a complete rearing cycle

2016

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INTRODUCCIÓNLa interacción entre la acuicultura y calidad de agua es un tema ampliamente conocido. Mientras que el volumen y la calidad de la cosecha, e incluso la viabilidad de la granja, dependen de la calidad del agua en la que se encuentra ubicada, las actividades de cultivo de peces son también una fuente potencial de deterioro de la calidad del agua, debido al aporte de diferentes tipos de materias y sustancias al medio acuático. Éstas pueden incluir estructuras plásticas y metálicas, alimento no consumido, productos metabólicos, productos químicos, microorganismos, parásitos, o animales ABSTRACT.The relationship between aquaculture activities and water quality plays an important role in determining the volume and quality of production as well as the impact of aquaculture on the aquatic environment. The natural assimilation capacity of a waterbody is often insufficient to cope with the continuous input of wastes from fish farms. Their impact depends not only on the waste itself, but also on other factors such as the local hydrodynamics at the farm site or the cultured species' feeding pattern. We combine a hydrodynamic model with a transport code to simulate the deposition of fecal pellets and uneaten feed from a gilthead seabream farm in the western Mediterranean Sea. The simulation spans a full 17-month rearing cycle and considers the natural variations in the feed demand of the fish during this period. The results indicated that the maximum benthic concentrations of organic matter and nutrients were found within a 100-500 m distance from the cages, depending on the type of particulate waste and on the local current characteristics. The combination of a long simulation period and realistic hydrodynamic patterns highlights the importance of considering long-term current variability when assessing the environmental impact of fish farms, and stresses the limitations of current simplistic assessment practices.

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Determination of physical behaviour of feed pellets in Mediterranean water

Cited by 27 publications

References 14 publications

Spatial and temporal extension of wild fish aggregations at Sparus aurata and Thunnus thynnus farms in the north-western Mediterranean

Spatial and temporal extension of wild fish aggregations at Sparus aurata and Thunnus thynnus farms in the north-western Mediterranean

Discharge of nutrient wastes from salmon farms: environmental effects, and potential for integrated multi-trophic aquaculture

Modeling the benthic loading of particulate wastes from a gilthead seabream (Sparus aurata) farm during a complete rearing cycle

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