Water quality observations in the marine aquaculture complex of the Deeba Triangle, Lake Manzala, Egyptian Mediterranean coast

Abstract

Coastal aquaculture is faced with extreme variation in water quality. The Deeba Triangle on Lake Manzala is the largest marine coastal aquaculture-producing area on the Egyptian Mediterranean. Samples from 16 ponds were taken during four seasons (2014-2015), to investigate the variation of 12 water quality parameters at that region. We tested the hypothesis that there is no spatial or temporal variation in water quality of the fish ponds. Fish ponds were statistically clustered into three groups (p = 0.0005) coincident with their geographical location. Hypersaline and transparent waters characterized the western ponds; higher dissolved oxygen and higher nutrients characterized the central region. These spatial differences were principally due to variations in salinity and nutrients of the water sources used for irrigation of the ponds and to differences in the aeration management styles. Strong seasonality was seen in water temperature (following air temperature), nutrients, and turbidity (following the seasonal cycles of various water sources from the Lake Manzala and the seasonality of the petrochemical plants effluents close to these ponds). We conclude that municipal effluents significantly affected, spatially and temporally, the quality of the irrigation water used for coastal aquaculture purposes, which consequently might affect fish yield.

Growth and nutrient bioextraction of Gracilaria chorda, G. vermiculophylla, Ulva prolifera, and U. compressa under hypo- and hyper-osmotic conditions

“…Although the land crops grew well in fish effluent, the bioremediation capacity of these plants was not promising. Fish production from brackish water aquaculture is significant, >9% of global fish production (Food and Agriculture Organization of the United Nations 2018) but there are serious water quality issues (El-Mezayen et al 2018).…”

Ecoepidemiology and Potential Transmission of Vibrio cholerae among Different Environmental Niches: An Upcoming Threat in Egypt

“…Islam [ 11 ] reported the synergistic association between the recurrence of cholera in Bangladesh and periods of high temperature with prolonged hours of sunshine, during which increasing photosynthesis and decreasing water volume resulted in a higher concentration of nutrients, green algal growth, and an increase in the aquatic bacterial load due to bacterial growth inside the algal sheaths. Another supportive study hypothesized that the onset of cholera epidemics after a period of endemicity is related environmentally to the decomposition of the algal bloom, which is also regulated climatically by the atmospheric water temperature and sunshine hours, in addition to the nutrient threshold conditions in the water [ 36 ]. Consequently, this scenario results in the release of bacteria into the aquatic environment in a condition associated with changes in reservoir growth and behavior and ultimately to the recovery, growth, proliferation, and sustainability of V. cholerae in the environment during the interepidemic periods.…”

The Problem of Environmental Pollution in the Mediterranean Sea Along the Coast of Turkey

“…Mainly, the organic nutrient loads discharged into the receiving waters cause eutrophication. Eutrophication is also lethal for fish species due to its toxic effect and oxygen depletion in the case of algal blooms [19]. Hence, river pollution control in the Mediterranean Sea area of Turkey is crucial to prevent nutrient discharge into the sea.…”