Environmental impacts of intensive aquaculture in marine waters

Tovar, Antonio; Moreno, Carlos; Mánuel-Vez, Manuel P.; Garcı́a-Vargas, Manuel

doi:10.1016/s0043-1354(99)00102-5

Cited by 180 publications

(104 citation statements)

References 1 publication

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“…The higher DO concentration at the outlet of Farm-A could be attributed to turbulence of the water. Similar observations were also accounted by Mirrasooli et al (2012) in Iran, Pulatsu et al (2004) in Turkey and Tovar et al (2000) in Arizona where DO concentrations were lower in outlets. Although the trend of turbidity in Farm-A and Farm-C gives an indication that outlets are having higher values (Table 1), there was no significant difference between the reference and impacted sites.…”

Section: Resultssupporting

confidence: 84%

“…It could be due to different sampling time in farms as pH in pond water is lowest during sunrise and increases with light intensity with CO 2 consumption and reaches peak value during afternoon (FAO, 2007). Contrary to this, increasing acidity was observed in downstream by Tovar et al (2000) in Spain. The pH in the impact zone of all the farms lie between 7.3 to 8.4 which falls within the good water quality criteria (6.5-9.5) given by Environmental Protection Agency (EPA, 2001).…”

Section: Resultscontrasting

confidence: 64%

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Assessment of physico-chemical parameters of rainbow trout farms for the evaluation of potential threat to natural streams in Nepal

Ghimire¹,

Niraula²,

Rai³

et al. 2017

Int. J. Environ.

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Three trout farms from Nepal were studied to investigate the changes in physico-chemical parameters and their potential threat to natural water bodies receiving the effluents. Reference and impact sites were determined in each farm so as to find out the level of impacts due to farming activities. Some of the parameters such as dissolved oxygen, turbidity, conductivity, and total dissolve solids were significantly changed in the impacted zones compared to reference sites. Similarly, concentrations of some major ions such as calcium and sodium were increased in the impacted zones. On the other hand, some of the parameters such as pH and potassium did not change in the impacted zone although their concentrations were different among farms studied. Nevertheless, the overall changes in the physico-chemical parameters did not pose health risk to the aquatic ecosystems receiving effluents from these fish farms as the concentrations were below the prescribed levels by Environmental Protection Agency (EPA) as well as Nepal Environment Statistics. This is an indication that, although fish farming activities are degrading water qualities, there is no threat to the water quality receiving the effluents yet probably due to small scale farming. The increase in number of fish farms in the same area, however might pose risk to the ecological health in the region which warrants regular monitoring.

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Section: Resultssupporting

confidence: 84%

Section: Resultscontrasting

confidence: 64%

Assessment of physico-chemical parameters of rainbow trout farms for the evaluation of potential threat to natural streams in Nepal

Ghimire¹,

Niraula²,

Rai³

et al. 2017

Int. J. Environ.

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“…The system can be considered as mesotrophic (sensu Nixon 1995), with nutrient concentrations in the sampling site varying broadly on a seasonal and tidal basis. Maximum concentrations are usually found in the winter, with values (µM) up to 1.4 (NO 2 -), 12 (NO 3 -), 42 (NH 4 + ) and 1.5 (PO4 3 -) (González-Gordillo 1999, Tovar et al 2000). Plants of Z. noltii were gathered carefully to keep belowground structures intact, and transported to the laboratory within 15 min of collection at ambient temperature.…”

Section: Methodsmentioning

confidence: 99%

Effect of shading by Ulva rigida canopies on growth and carbon balance of the seagrass Zostera noltii

Brun¹,

Vergara²,

Navarro³

et al. 2003

Mar. Ecol. Prog. Ser.

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The effects of macroalgae blooms on seagrasses were assessed by shading Zostera noltii Hornem. with Ulva rigida C. Agardh mats under laboratory and field conditions. In the laboratory, where there was no direct contact between U. rigida and Z. noltii, leaf, rhizome, and root elongation rates, as well as gross production, declined as a function of U. rigida layers, causing a mobilization of non-structural carbohydrates in both above-and belowground tissues to meet carbon demands. However, when shading was performed in the field, where direct contact exists between Z. noltii and U. rigida, Z. noltii responses were not proportional to the number of Ulva layers. Elongation rates and gross production were reduced by U. rigida shading, with the lowest values under 2 Ulva layers, while there were no significant differences between controls and 4 U. rigida layers. This suggests another Ulva effect occurs besides shading. To test the likely effect of dissolved organic carbon (DOC) derived from U. rigida, Z. noltii plants were cultured under light limitation with radioactive dissolved organic carbon (DO 14 C) released by U. rigida. Plants cultured under a full DO 14 C load showed a significant enhancement of growth. The DO 14 C disappeared from the culture medium during the first 4 d of culture as a linear function of external DO 14 C concentration. This was coupled to a linear increase of radioactive particulate organic carbon (PO 14 C) in aboveground tissues, while a substantial part of this PO 14 C was allocated in belowground tissues. Overall, the PO 14 C incorporated in Z. noltii plants represented ca. 20 to 25% of the DO 14 C which had disappeared. Therefore, a net transfer of DO 14 C from U. rigida to Z. noltii has been documented. Other additional possibilities, such as a light quality effect or other kind of signals (i.e. growth factors), are discussed.KEY WORDS: Eutrophication · Heterotrophic DOC uptake · Dissolved organic carbon · Seagrass · Non-structural carbohydrates · Light reduction Resale or republication not permitted without written consent of the publisher

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“…In fish culture, it is common to use pour quality feed and inadequate strategies, such as the use of high volumes of feed without considering the load capacity of the culture systems. This leads to an excessive accumulation of organic residues from feed leftovers, and fish excrement, what causes a reduction in the levels of oxygen and increases the concentration of toxic substances (Tovar et al, 2000). In order to minimize the impact of these problems, producers should have minimum protocol to assure safety, respecting the maximum fish load in a given area, improving feed management techniques, minimizing waste by using good quality, highly digestible feed (Rosenthal, 1994), with lower concentrations of nitrogen and phosphorus, without reducing its nutritive value (Boyd, 1999).…”

Section: Introductionmentioning

confidence: 99%

Characterization and evaluation of the impact of feed management on the effluents of Nile tilapia (Oreochromis niloticus) culture

Baccarin

Camargo

2005

Braz. arch. biol. technol.

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Environmental impacts of intensive aquaculture in marine waters

Cited by 180 publications

References 1 publication

Assessment of physico-chemical parameters of rainbow trout farms for the evaluation of potential threat to natural streams in Nepal

Assessment of physico-chemical parameters of rainbow trout farms for the evaluation of potential threat to natural streams in Nepal

Effect of shading by Ulva rigida canopies on growth and carbon balance of the seagrass Zostera noltii

Characterization and evaluation of the impact of feed management on the effluents of Nile tilapia (Oreochromis niloticus) culture

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