Reproduction
Young-of-the-Year Atlantic Sharpnose Sharks
Elasmobranch life history patterns are commonly characterized by slow growth, long life, large adult size, late sexual maturity, annual or biennial reproduction, long gestation period, reduced fecundity, and well-developed, highly mobile offspring.
Elasmobranchs display three distinct embryonic developmental strategies:
- oviparity - producing embryos in eggcases that hatch outside the body (e.g., sharks in the order Heterodontiformes and rays in the order Rajiformes)
- aplacental viviparity - producing embryos that come to term in utero and draw nourishment from a yolksac (e.g., some sharks and all non-Rajiform rays)
- viviparity - producing embryos that come to term in utero and draw nourishment from the female via an umbilical attachment (e.g., all reqiuem and hammerhead sharks).
Atlantic Angel Shark Embryo and Yolksac
For a quantitative study regarding life history patterns in sharks and an examination of potential correlations between traits related to body size, reproduction, age, and growth, see: Cortés, E. (2000) Life-history patterns and correlations in sharks. Rev. Fish. Sci. 8:299-344.
The Shark Population Assessment Group is currently conducting reproduction studies on several species, including the Atlantic angel shark Squatina dumerili, blacknose shark Carcharhinus acronotus, blacktip shark C. limbatus, cownose ray Rhinoptera bonasus, sandbar shark C. plumbeus, finetooth shark C. isodon, and roundel skate Raja texana. Results from previous reproduction and life history studies can be found by clicking the Publications link on the right.