Alosa "oligorakered." The multirakered are primarily plankton feeders, the oligorakered have large rakers and are predators, and the medium-rakered generally consume a mixed diet. Most current species of the genus "Alosa" in North America can be found in Florida, whereas the distribution of most of them is broader. Morphology is notoriously liable to adapt to changing food availability in these fish. Several taxa seem to have evolved quite recently, making molecular analyses difficult. In addition, hybridization may be a factor in shad phylogeny. Nonetheless, some trends are emerging. The North American species except the American shad "A. sapidissima" can probably be
Alosa Most individuals die shortly after spawning. "Alosa" species are seemingly very adaptive vertebrates, so can change readily to adapt to their environments, as species are found in a variety of temperatures and waters. As "Alosa" species are generally anadromous, they are faced with various obstacles to survival. They may have to pass through numerous barriers and waters to get to either their spawning grounds or normal habitats (the sea in most cases). Estuaries are a major factor in numerous "Alosa" species' migration. Estuaries can be highly variable and complex environments contributing to fluctuating biological interactions, with shifts in osomolarity, food