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
Weymouth Back River Whitman's Pond was dammed to turn the machines which processed the natural bog iron for the Weymouth Iron Works. Later, the Commonwealth of Massachusetts installed a herring ladder to allow the herring to bypass the dam on their spawning runs. Historically the herring ran to Whitman's Pond, and beyond up Mill River and Swamp River, to Great Pond. River herring commonly refers to two species, Blueback herring ("Alosa aestivalis") and alewife ("(Alosa pseudoharengus)"). Today, 1/2 million river herring and Rainbow smelt ("Osmerus mordax") run up the river each year to spawn (although they are not able to ascend the fish