Skating through development

Abstract

Oviparity is an ancestral reproductive strategy in which females lay fertilized eggs to the environment. During development, the offspring rely solely on the resources provided by the yolk sac to favor growth and maturation. This type of nutrition is also known as “lecithotrophy.” The clear‐nosed skate (Raja eglanteria) is an Atlantic coast species that uses this reproductive pattern. Skates usually produce two eggs, which are fertilized in the oviduct by stored sperm and subsequently released. The egg, also referred to as Mermaid’s purse, has a horn at each of its four corners with a respiratory canal at the base. By midgestation, tail beating of the embryo brings water inside. The yolk sac diminishes in size as the developing embryo grows. At 12 weeks of development, the skate is ready to hatch and will be fully independent.