Courtship in sevengill sharks is complex. The exact form of courtship is unknown, but it involves the male continuously biting the female to attract her attention. Eventually, the male lies side-by-side with the female, inserts his claspers and holds on during mating by grasping onto the gill opening or pectoral fins by biting into them. What leads to courtship is unknown because it has rarely been observed.
Mating System: polygynandrous (promiscuous)
The mode of reproduction is ovoviparous. Spawning frequency for broadnose sevengill sharks occurs in one clear seasonal peak per year. Females move to shallow bays to give birth after a gestation period of 12 months, which occurs during spring and early summer. Sevengill sharks have large litters of 82 to 95 young each about 40 to 45 cm in length. For the first few years, young pups remain in coastal shallow bays, which provide protection from predators, until they are mature enough to migrate to offshore environments. The average reproductive age is not known but is believed to be between 20 to 25 years in females. Females give birth every two years (every 24 months) after consecutive year-long ovarion and gestation cycles meaning the reproductive cycle is biennial.I n general, this species has low fecundity, is slow growing, gives birth to large young, matures late, lives long, and has high survival rates.
Breeding interval: Breeding occurs once every two years.
Breeding season: Breeding occurs in spring and early summer months.
Range number of offspring: 82 to 95.
Range gestation period: 12 (high) months.
Range age at sexual or reproductive maturity (female): 11 to 21 years.
Range age at sexual or reproductive maturity (male): 4.3 to 5 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); ovoviviparous
The young are nurtured internally. The eggs hatch within the females body and the young are nourished via an independent yolk sac located within the female's uterus. Upon depletion of the yolksac, the embryo obtains nutrients from uterine secretions until birth occurs. After birth, young feed independently lacking maternal or paternal assistance, there is no post-birth parental care.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female)