Environmental effects of a marine fish farm of gilthead seabream (Sparus aurata) in the NW Mediterranean Sea on water column and sediment

Abstract

WileyMorata Higón, T.; Falco Giaccaglia, SL.; Gadea, I.; Sospedra Ciscar, J.; Rodilla Alamá, M. (2013). Environmental effects of a marine fish farm of gilthead seabream (Sparus aurata) This study examined the effects of organic enrichment on water column, sediments and macrofauna caused by a fish farm in the Mediterranean Sea. Samples were collected on four sampling campaigns over a one-year cycle. Significant differences were found in the water column in dissolved oxygen, dissolved inorganic nitrogen, phosphate and total phosphorus concentrations between the fish farm and the control. The increase in the dissolved inorganic nitrogen and phosphate concentrations at the fish farm modified the stoichiometric ratios between nutrients, with silicate acting as limiting nutrient at the fish farm 11% more than at the control. Nevertheless, chlorophyll a concentration in the water column was higher at the control station, probably due to the fouling of the underwater fish farm structures. Significant differences were found in sediment concentrations of organic matter, total phosphorus and redox potential between the fish farm and the control. The Canonical Correlation Analysis indicated that organic matter, total phosphorus, redox potential and % of gravels accounted for 68.9% of the total variance in the species data. Changes were observed in macrofauna, with a decrease in number of species and up to a nine-fold increase in abundance with respect to the control.

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

“…This can lead to an alteration of the distribution, type, and physiological activity of the benthic communities. Morata et al (2015), for instance, found a notable decrease in specific richness and a 9-fold increase in abundance under a NW Mediterranean seabream farm, similar to the one considered here, as compared to a control station.…”

“…The highest concentrations are found relatively close to the individual fish pens, within a 100-m radius, but this distance depends strongly on the physical characteristics of the waste particles and on the variability of the prevailing water currents. The abundance of C at the seabed in this area modifies the redox potential (turning it more negative, Morata et al 2015) and increases the metabolism of the sediment, enhancing also oxygen consumption. This can lead to an alteration of the distribution, type, and physiological activity of the benthic communities.…”

“…Las concentraciones más altas se encuentran relativamente cerca de las jaulas, dentro de un radio de aproximadamente 100 m, aunque esta distancia depende fuertemente de las características físicas de las partículas de residuos y, sobre todo, de la variabilidad de las corrientes marinas dominantes. La abundancia de C orgánico en el fondo marino modifica el potencial redox (haciéndolo más negativo, Morata et al 2015) y, por tanto, aumenta el metabolismo de los sedimentos e incrementa el consumo de oxígeno, lo cual puede provocar una alteración en el tipo, la distribución y la actividad fisiológica de las comunidades bentónicas. Morata et al (2015), por ejemplo, encontraron accumulate, the selection of easily accessible but representative sampling points might be a difficult task.…”

“…La abundancia de C orgánico en el fondo marino modifica el potencial redox (haciéndolo más negativo, Morata et al 2015) y, por tanto, aumenta el metabolismo de los sedimentos e incrementa el consumo de oxígeno, lo cual puede provocar una alteración en el tipo, la distribución y la actividad fisiológica de las comunidades bentónicas. Morata et al (2015), por ejemplo, encontraron accumulate, the selection of easily accessible but representative sampling points might be a difficult task. Often, sampling will be replaced by estimations done using simplified models (e.g., based on one-day current data, constant waste production, uniform bathymetry) that only provide a simple description of the real problem.…”

Benthic Recovery after the Cessation of a Gilt‐head Seabream, Sparus aurata, Farm in the Mediterranean Sea

“…The differences in macrofauna, found in the farming area and the control station before cessation, were largely as a consequence of organic enrichment occurring in sediments under the cages (Morata et al ). C. capitata was found under the cages before the cessation in densities of 31,151 ind/m 2 , and it is thought to be an indicator par excellence of anoxic conditions (Rosenberg ) and is classified as an opportunistic species (Pinedo et al ).…”