Impact of aquacultures on the marine ecosystem: Modelling benthic carbon loading over variable depth

Jusup, Marko; Geček, Sunčana; Legović, Tarzan

doi:10.1016/j.ecolmodel.2006.08.007

Cited by 34 publications

(33 citation statements)

References 18 publications

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“…Different sets of biological and chemical variables have been proposed for evaluating the local-scale interaction between fish cages and the benthic ecosystem (Giles 2008, Hargrave 2010. Most mathematical models which, thus far, have been applied to EIA net pens, only permit modifications of benthic indicators to be predicted at a local scale (González et al 2002, Holmer et al 2005, Jusup et al 2007, Cromey et al 2012; see also www.ecasatoolbox.org).…”

Section: Introductionmentioning

confidence: 99%

Modelling biogeochemical fluxes across a Mediterranean fish cage farm

Brigolin¹,

Meccia²,

Venier³

et al. 2014

Aquacult. Environ. Interact.

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An integrated approach is described for modelling interactions between off-shore fish cages and biogeochemical fluxes of carbon (C), nitrogen (N) and phosphorus (P). Two individual-based population dynamic models for European seabass Dicentrarchus labrax and gilthead seabream Sparus aurata were coupled with a Lagrangian deposition and a benthic degradation model. The individual models explicitly take into account the effects of water temperature and feed availability on fish growth. The integrated model was tested at a Mediterranean fish farm where a comprehensive set of in situ environmental and husbandry data was available. Tests were performed to compare the predicted and observed total organic carbon (TOC) concentrations in surface sediment under and near fish cages. At a local scale, the model output simulated the spatial distribution of 4 biogeochemical indicators, namely: TOC concentrations, C fluxes towards the seabed and C:N and C:P ratios. These allowed the most impacted areas and more extended areas of intermediate organic enrichment to be identified. The model was also used for estimating the mass balance of C, N and P, in order to determine the potential cumulative effects of multiple fish farms in the same area. The C, N and P fluxes among feed, fish and environment were calculated for each fish species over 24 mo of farm activity. The results showed that the amount of dissolved N directly released into the water column in inorganic form (ammonia/urea) was comparable to that deposited on the seafloor in particulate form as uneaten feed and faeces. A larger fraction of P (about 65%) was released as faeces. Results from the integrated model yielded useful information for assessing the sustainability of an area for aquaculture activities that could be used to provide a scientific rationale for fish farm development in new areas.

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Section: Introductionmentioning

confidence: 99%

Modelling biogeochemical fluxes across a Mediterranean fish cage farm

Brigolin¹,

Meccia²,

Venier³

et al. 2014

Aquacult. Environ. Interact.

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“…The number of events was imposed on the basis of the 2010 current time series and of previous current meter deployments available for this area (Rampazzo et al, 2013;Giovanardi et al, 2003). The effects of tide and storm events were therefore accounted for in the final time series, while short-term fluctuations related to turbulence were accounted for by the deposition model, as reported by Jusup et al (2007).…”

Section: Est1 Est2 In1 Est1mentioning

confidence: 99%

“…The bathymetry of the farmed area can either be specified through an external file or assumed to be flat. Faeces and pseudofaeces deposition from mussel lines is simulated by means of a Lagrangian technique, consistent with the advection-diffusion equation (details in Jusup et al, 2007). The effect of structures on the current within the farm was not accounted for in the present work, due to the lack of 2-D current meter data required (e.g.…”

Section: Model Theory: Mussel Farm Deposition Model and Early Diagenementioning

confidence: 99%

“…Current meter data were first processed by means of a classical harmonic analysis, in order to extract tidal components as well as long-term residual means (Pawlowicz et al, 2002). On the basis of the procedure proposed by Jusup et al (2007), the residual currents were therefore edited randomly for short periods of time in order to reproduce the variability recorded from current meter measurements during extreme events (i.e. storms).…”

Section: Est1 Est2 In1 Est1mentioning

confidence: 99%

“…The ordinary differential equations were integrated numerically by means of a fourth-order Runge-Kutta scheme (Press et al, 1987). The Lagrangian equation for the deposition model was solved following Jusup et al (2007). The set of partial differential equations in the EDM was numerically solved by means of an implicit method; details on the operator splitting technique -a sequential non-iterative approach -and the definition of the function residuals and the Jacobian matrix are provided in Aguilera et al (2005) and Regnier et al (2002).…”

Section: Model Theory: Mussel Farm Deposition Model and Early Diagenementioning

confidence: 99%

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Modelling biogeochemical processes in sediments from the north-western Adriatic Sea: response to enhanced particulate organic carbon fluxes

et al. 2018

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Abstract. This work presents the result of a study carried out in the north-western Adriatic Sea, by combining two different types of biogeochemical models with field sampling efforts. A longline mussel farm was taken as a local source of perturbation to the natural particulate organic carbon (POC) downward flux. This flux was first quantified by means of a pelagic model of POC deposition coupled to sediment trap data, and its effects on sediment bioirrigation capacity and organic matter (OM) degradation pathways were investigated constraining an early diagenesis model by using original data collected in sediment porewater. The measurements were performed at stations located inside and outside the area affected by mussel farm deposition. Model-predicted POC fluxes showed marked spatial and temporal variability, which was mostly associated with the dynamics of the farming cycle. Sediment trap data at the two sampled stations (inside and outside of the mussel farm) showed average POC background flux of 20.0-24.2 mmol C m −2 d −1 . The difference of organic carbon (OC) fluxes between the two stations was in agreement with model results, ranging between 3.3 and 14.2 mmol C m −2 d −1 , and was primarily associated with mussel physiological conditions. Although restricted, these changes in POC fluxes induced visible effects on sediment biogeochemistry. Observed oxygen microprofiles presented a 50 % decrease in oxygen penetration depth (from 2.3 to 1.4 mm), accompanied by an increase in the O 2 influx at the station below the mussel farm (19-31 versus 10-12 mmol O 2 m −2 d −1 ) characterised by higher POC flux. Dissolved inorganic carbon (DIC) and NH + 4 concentrations showed similar behaviour, with a more evident effect of bioirrigation underneath the farm. This was confirmed through constraining the early diagenesis model, of which calibration leads to an estimation of enhanced and shallower bioirrigation underneath the farm: bioirrigation rates of 40 yr −1 and irrigation depth of 15 cm were estimated inside the shellfish deposition footprint versus 20 yr −1 and 20 cm outside. These findings were confirmed by independent data on macrofauna composition collected at the study site. Early diagenesis model results indicated a larger organic matter mineralisation below the mussel farm (11.1 versus 18.7 mmol m −2 d −1 ), characterised by similar proportions between oxic and anoxic degradation rates at the two stations, with an increase in the absolute values of oxygen consumed by OM degradation and reduced substances re-oxidation underneath the mussel farm.

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Fish farming and its appeal to common bottlenose dolphins: modelling habitat use in a Mediterranean embayment

Bonizzoni

Furey

Pirotta

et al. 2013

Aquatic Conservation

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1. Common bottlenose dolphins Tursiops truncatus interact with fish farms in the Mediterranean Sea. These interactions were investigated in a Greek bay by incorporating multiple geographic, bathymetric, oceanographic, and anthropogenic variables. 2. Generalized additive models (GAMs) and generalized estimation equations (GEEs) were used to describe dolphin presence. Visual surveys were conducted over 2909 km under favourable viewing conditions that included 54 dolphin group follows for 457 km. Sea surface temperature (SST) and chlorophyll‐a (Chl‐a) data were obtained from remote sensing imagery, and distances to sources of human influences including fish farms, a ferro‐nickel plant, and a slag disposal area were calculated within a geographic information system (GIS). 3. Bottlenose dolphins were encountered mainly in the south‐eastern portion of the study area, and occurrence was not clearly related to SST and Chl‐a, nor the ferro‐nickel plant or nearby slag disposal area. 4. Dolphin occurrence generally increased within 20 km of fish farms, with four farms and dolphins displaying a positive relationship, seven no clear relationship, and two a negative one. 5. While it is likely that uneaten food and other detritus attract dolphin prey, individual farms (or clusters of farms) clearly had a different appeal. The proximity of the ferro‐nickel plant and slag disposal area to ‘attractive’ fish farms could compromise dolphin health, but physiological data are unavailable. 6. The modelling of multiple variables allowed for a description of dolphin habitat use and attraction to some fish farms. More such data analysed in similar manner would be instructive for other areas where marine mammals and fish farms co‐occur. Copyright © 2013 John Wiley & Sons, Ltd.

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Impact of aquacultures on the marine ecosystem: Modelling benthic carbon loading over variable depth

Cited by 34 publications

References 18 publications

Modelling biogeochemical fluxes across a Mediterranean fish cage farm

Modelling biogeochemical fluxes across a Mediterranean fish cage farm

Modelling biogeochemical processes in sediments from the north-western Adriatic Sea: response to enhanced particulate organic carbon fluxes

Fish farming and its appeal to common bottlenose dolphins: modelling habitat use in a Mediterranean embayment

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