Influence of some physico-chemical variables on wild fish richness beneath sea-cage fish farms in the Aegean Sea, Turkey

Abstract

This study aims to determine the relationship between physico-chemical variables on a seasonal basis and wild fish assemblages beneath sea-cage fish farms. Assemblages of wild fish were counted monthly on two separate days at each of six fish farms between August 2015 and July 2017, by six rapid visual counts (RVC) in 5 minutes with scuba by two divers. Seawater samples were simultaneously taken by a Nansen bottle during the RVC from the fish farm barge. SST (°C), salinity (ppm), dissolved oxygen (mg l−1) and pH were measured by YSI multiparameter, while Secchi disk was also used for light transmittance. Wild fish species richness went up with increasing temperature and salinity in the Izmir region, however, this stopped at about 26°C and about 39 ppm. Wild fish richness increased when the DO was at a level of 7 mg l−1 and the pH at about 7.9 in Izmir. Between 10 and 20 m, light transmittance showed greater wild fish species richness in Izmir region. In contrast, the wild fish species richness of the Muğla region fluctuated more. In terms of wild fish species richness, these fluctuations increased with salinity and DO, while they decreased with SST, pH and light transmittance. However, the range of variation of the recorded physico-chemical variables is rather narrow. The results of the correlation matrix indicate that the relationship between wild fish species richness and pH and SST was statistically significant in Izmir region (P < 0.05).

Effects of anthropogenic activities on nutrient parameters in the North Eastern Mediterranean Sea (Bay of Sığacık/Aegean Sea)

“…This situation, together with the effect of winds, resulted in a homogeneous mixing of the water column. Akyol et al (2020) determined that the salinity value was high in the Aegean Sea between August and September. Similar results regarding the formation of high salinity in summer and low in winter were reported by Kucuksezgin et al (2019), Kaymaz & Özdemir (2019), Aydin-Onen et al (2012) and Orçun & Sunlu (2007).…”

“…Research on marine pollution is essential to maintain the continuity of populations of existing species living in the seas and to enable future generations to develop in a healthier and more suitable environment. In this regard, there are numerous individual or institutional studies on physicochemical parameters and sediment samples from the Aegean Sea (Aksu 2009;Aydin-Onen et al 2012;Başaran et al 2006;Başaran et al 2010;Kaymakçı et al 2001;Kükrer & Aydın 2006;Kükrer & Büyükışık 2013;Kontaş et al 2004;Küçüksezgin et al 2006;Kocataş 2004;Orçun & Sunlu 2007;Sunlu et al 2012;Kucuksezgin et al 2019;Türk Çulha & Karaduman, 2020;Akyol et al 2020;Kucuksezgin et al 2021). These studies are quite extensive and efforts have been made to identify major pollution points in the Aegean Sea.…”

Aquaculture monitoring system using multi-layer perceptron neural network and adaptive neuro fuzzy inference system

“…In a study conducted by Zhang et al [6] in the Zhuanghe River of China, the most significant indicators affecting water quality were found to be DO, water temperature, and pH value. Akyol et al [7] studied fish farm species richness in the Aegean Sea and determined that water temperature, pH value, and DO content were the three primary factors influencing fish richness. Jafari and Khayamian [8] employed corona discharge ion mobility spectrometry (CD-IMS) in their research.…”

Evaluation of Aquaculture Water Quality Based on Improved Fuzzy Comprehensive Evaluation Method

“…Zhang Xianyu et al, researched the water quality of pond and cage-aquaculture areas in Zhuanghe River, China, and the results show that among multiple indicators, dissolved oxygen, water temperature and pH value are the most important factors affecting the water quality [7]. Akyol O et al, monitored species richness of the fish farms in the Aegean Sea [8]. The results showed that water temperature, pH value and dissolved oxygen content were the three main factors that determined fish richness.…”