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
Mattapoisett River mill purposes" and featured three herring weirs; the "Upper Herring Weir" in Rochester, the "Middle Weir" or "Church's Weir", and the "Lower Herring Weir" at the entrance to Mattapoisett Harbor. Fish populations drastically declined during the twentieth century until they were almost extinguished, but local restoration efforts from the 1980s onwards have fostered a slow recovery. The principal restoration tactic has been to remove snags and other obstacles from the river that serve to impede fish migrations. The Lower Herring Weir is one of the few rivers emptying into Buzzards Bay that has electronic fish counters installed. Reports from Alewives