Grey Nurse Sharks are very slow to breed and can only produce a maximum of two pups each year which makes them particularly vulnerable to overfishing. When fish are removed from the environment at a faster rate than they can breed it is inevitable that the species will decline.

The Grey Nurse Shark grows slowly and takes 4 - 6 years to mature with both males and females maturing at about 220cm total length. Many scientists believe that Grey Nurse Sharks come together at certain times of the year in large groups at specific locations which is when mating occurs. The precise timing of mating and pupping in Australian waters is unknown.

Once she has mated the female Grey Nurse Shark stores the sperm inside her body while the ovaries produce eggs that move to the oviduct where they are fertilised. Not all migrating females are sexually active and they generally only reproduce once every two years.

Inside the mothers body the baby Grey Nurse Shark hatch from eggs inside the uterus with only one baby shark fully developing in each uterus. One challenge for the species is that they breed very slowly with only a maximum of two babies being born at any time. Baby Grey Nurse Sharks that are fully formed and independent of their mothers are born between 9 and 12 months after mating.

1. Fishing Impacts: Perhaps the greatest threat to recovery of Grey Nurse Shark populations is animals being killed as “by-catch” when they are caught accidentally in fishing activities that are targeting other species of fish. This occurs both in recreational as well as commercial fishing activity.

Grey Nurse Sharks are however “hooked” accidentally by recreational fishers seeking other species. This is a significant cause of the large numbers of sharks that are seen with wire traces and lures attached to their mouths and bodies. (Link to images of Grey Nurse Shark with lures).

Some sharks are also caught accidentally by commercial fishers as by catch (non-target fish caught in the net). In a few cases Grey Nurse Sharks caught this way have had their fins removed in a practice known as shark finning, an activity that results in many shark species around the world having their fins removed while still alive. The high value of shark fins leads to levels of catch of sharks worldwide that is unsustainable.