Ecosystem and Commercializing of Fish in a Rich-Minerals, Low-Salinity Closed Lake

Abstract

Wadi El Natrun is an elongated narrow depression in the Western Desert of Egypt. The depression characterized by many ancient alkaline salt lakes. These lakes are filled with water in winter and dried up in summer. Recently, some lakes become permanently dried, while others become submerged throughout the year as El Bieda Lake. El Bieda Lake has undergone ecological changes due to the prolonged extraction of minerals and the continual discharging of freshwater. This study investigates the recent biotic and abiotic changes of this lake and discusses its fisheries opportunities. The lake’s water is well-oxygenated, rich with different inorganic nutrients, and characterized by a low salinity. Sodium and chloride ion concentrations are lower than the equivalent surface seawater, while magnesium, calcium, potassium, sulfate, and bicarbonate ions are higher. The lake has low plankton species richness with high biomass and high nutritional values. More recently, two cichlid species, Oreochromis aureus and Coptodon zillii, have colonized the lake. Summer characterized by a very low mortality for Oreochromis aureus and a poor representation of Coptodon zillii. However, both species shared the catch the rest of the year. The high biomass and nutritional quality of plankton communities, as well as the dense phytobenthic film, indicate that the lake is currently below its carrying capacity. The well-oxygenated water, high biomass of plankton and phytobenthic diatoms, and the expected changes in salinity suggest that introducing the euryhaline, commercially valuable, and fast-growing Mugil cephalus or Chelon ramada in El Bieda Lake is highly advisable.

Chemical, biochemical, and bioactivity studies on some soda lakes, Wadi El-Natrun, Egypt

“…3.28 mg/L). This is due to increasing salinity in H1 and temperature elevation during summer (Abdelkarim et al, 2023 ). The average values of both BOD and COD at H2 ( avr.…”

“…Extending approximately 60 km from north to south, this depression is renowned for its historical and ecological significance and characterized by a series of hypersaline lakes, including Um Risha, Ruzita, El-Khadra, Abou Jiyad, and El-Hamra. Some lakes completely evaporated with precipitated minerals on the overlying sediment, whereas others are still filled with water mainly regenerated from the underground regime (Abdelkarim et al, 2023 ). The two hypersaline lakes, i.e., El-Hamra Lake 1 (H1) and El-Hamra Lake 2 (H2), are in the middle of Wadi El-Natrun Lakes.…”

“…Salt lakes are distributed worldwide and across various African countries, particularly in the East African Rift System (EARS) where tectonic activities have led to the formation of several alkaline and saline lakes such as Lake Turkana in Kenya and Ethiopia and Lake Natron in Tanzania (Lameck et al, 2023 ). Other soda lakes are found in northern African countries, e.g., Wadi El-Natrun in Egypt, Chott El-Jerid in Tunisia, and Algeria (Abdelkarim et al, 2023 ; Achour & Saadi, 2023 ). Certain soda lakes are characterized by distinct colors: faint yellow, deep green, and red.…”