Sockeyes spawn mostly in streams having lakes in their watershed. Most species have separate female and male sexes, but there also are many species that are hermaphrodites, meaning that a private has both testes and ovaries. Generally, a hermaphrodite can only produce one type of gamete, sperm or eggs, at a time, so their gametes must be cross-fertilized by another member of the species. Until fairly recently, this type of reproduction had only been shown in bony fish. In 2007, scientists confirmed that a pup born to an isolated female hammer head shark. Since most fish species undergo external fertilization, it only makes sense that, for the vast majority of fish species the eggs develop outside of the mother’s body. This mode of development is called oviparity and is used by many species that undergo internal fertilization as well. In these cases, the eggs are released into the water for external development only after fertilization has taken place. In contrast, most shark and ray species develop their eggs inside of their bodies but without direct nourishment from the mother, a system called ovoviviparity. Developing ovoviviparous embryos are nourished internally from a yolk sac, and they are delivered as live young. There are also some species of sharks, such as lemon sharks, that do provide maternal nourishment for their internally developing eggs. This is called Vivi parity, and nutrients are usually supplied through an organ called the placenta that connects to the mother’s blood supply. In order that survival of young be more than optimum, the timing of spawning by the mature adult fish is so adjusted that must be closely linked to the availability of maximum congenial environment added by increased food availability of food for the newly hatched young ones