Alosa algeriensis Alosa algeriensis Alosa algeriensis, the North African shad, is a Mediterranean species of clupeid fish in the shad genus "Alosa". "Alosa algeriensis" is primarily found in the Mediterranean Sea from northern Morocco to northern Tunisia. They are also found in Sardinia, Italy with landlocked populations in Lake Ichkeul, Tunisia and Sardinia, Italy. "Alosa algeriensis" males will begin upriver migration at about 3–4 years old while females do not begin until about 4–5 years old. The juveniles migrate to the mouth of rivers until they mature. Once temperatures rise above 20 degrees Celsius, they will begin their spawn. Mortality usually occurs
Subterranean river Subterranean river A subterranean river is a river that runs wholly or partly beneath the ground surface – one where the riverbed does not represent the surface of the Earth (rivers flowing in gorges are not classed as subterranean). It should also not be confused with an aquifer which may flow like a river but is contained within a permeable layer of rock or other unconsolidated materials. Subterranean rivers may be entirely natural, flowing through cave systems. In karst topography, rivers may disappear through sinkholes, continuing underground. In some cases, they may emerge into daylight further downstream. Some fish (popularly