Mucilage Problem in the Sea of Marmara
Effect of Mucilage on Fish Health
Tülay Akaylı, Çiğdem ÜrküşMarine mucilage has been widely seen in the Mediterranean in recent years; is a natural phenomenon, also called sea slime, sea slobber, and polluted sea phenomenon. Today; The significant increase in the amount of mucilage in the seas has become a worldwide public health, economic and environmental problem. There are various phytoplankton, colloidal components, and various microorganisms (various prokaryotes such as bacteria, and viruses) in the structure of mucilage. The mucilage layer covers the water's surface; Since it significantly blocks the sunlight reaching the marine ecosystems, it covers the gills of the sea creatures living under this layer, cutting off the oxygen and causing their death. In addition, opportunistic human pathogens in seawater as well as other environmental microorganisms can develop in the mucilage layer. This study was carried out to investigate the effect on the health of some pelagic marine fish species caught by angling of mucilage mass, which was seen intensely in Istanbul in June 2021. Live fish samples used in the study were obtained from 4 different regions. Parasitological, bacteriological, and histopathological examination methods were applied to various fish species such as mullet (Mugil cephalus), bluefish (Pomatomus saltatrix), horse mackerel (Trachurus trachurus), and anchovy (Engraulis encrasicolus) in the laboratories of our faculty. In addition, bacteriological cultivations were made from mucilage samples taken from seawater. While no clinical findings were observed in all fish samples examined, the presence of thin mucilage layers in the wet preparations prepared from the gills and skin of these fish was noted. However, some differences were noted in the internal examination of the autopsied fish samples. Isolates of different Vibrio and Pseudomonas species were obtained as a result of bacteriological cultivation from the liver samples. According to the data from this study, it has been determined that marine fish were stressed because of mucilage and that the gill and liver tissues of these fish were most affected. It has also been determined that the isolated bacterial species were not pathogenic to humans and consisted of bacteria species that could be found in the typical flora of seawater and fish. In addition, in this study, Vibrio diazotrophicus species, which is commonly found in the marine environment and whose nitrogen-fixing ability was detected, was isolated and identified for the first time in mucilage-containing water samples.