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
Herring scad shallow coastal regions where it inhabits the surface layers of the ocean over a variety of substrates. The herring scad is a carnivorous species, known to consume a variety of crustaceans including shrimps, copepods and decapods as well as other small fishes. It is one of a number of pelagic fish from the Red Sea found to have high numbers of luminescent bacteria in its gut, living symbiotically with the fish as part of the gut flora. Parasites of the herring scad include the philometrid nematode "Philometra austropacifica", which lives inside the ovary of the females. The species is of