Environmental Monitoring Around an Offshore Fish Farm with Copper Alloy Mesh Pens in the Northern Aegean Sea

Abstract

In the present study, environmental monitoring was undertaken around an offshore fish farm with copper alloy mesh pens located in the Northern Aegean Sea. From the water velocity results obtained at the farm site, located in the Strait of Canakkale (formerly the Dardanelles) it was recorded that the horizontal water velocity reached 36cms^-1 at select times. The average water velocity was found to be 22cms^-1. Water quality measurements were made over an 11 months period between September 2011 and July 2012. Other than occasional wind drawn mixing events, the two different water masses can be clearly indicated depending on the temperature and salinity values recorded throughout the study period in the Strait of Canakkale. Inorganic nutrient concentrations such as NO^-₂+NO^-₃, NH₄, PO₄, TP and SiO₂, changed from low to moderate through most of the sampling period. The data for TSS varied among sampling depths between 0.06 and 10.40 mgL^-1, being below the typical seawater quality measurement threshold of 30 mgL^-1 pronounced by Water Pollution Control Regulations. Chlorophyll-a concentration, ranged between 0.143-2.633μgL^-1, 0.055-1.519 μgL^-1, and 0.110-2.288 μgL^-1, at the surface, 15m, and 30m, respectively. It has been observed that starting from March 2012, especially in Stations 2 and 3, the phytoplankton abundance controlled the TSS, rather than terrestrial sources.