The Jervis Bay Environment
Sharks and Rays
Jervis Bay is home to a vast number of cartilaginous fish - the sharks, skates and rays, of which can be seen all year round.
Grey Nurse Sharks migrate to our southern waters in the summer months where they form aggregations in shallow waters, most commonly at our dive sites around Bowen Island. In the winter, Port Jackson Sharks move in from the deeper waters to form huge breeding aggregations, where they mate and lay spiral shaped eggs that take nearly a year to hatch. The Gulf Wobbegong and Spotted Wobbegong are huge bottom dwelling sharks that can be found all year round. As well as Blind Sharks, which can be seen hunting at night, and hiding in rock crevices during the day. If you're lucky, the elusive Angelshark can be spotted, perfectly camouflaged in it's ambush position on the sandy bottom.
Sightings of huge Smooth Stingrays are a common occurrence, as well as the much smaller stingarees (both Common and Kapala stingarees) that lay still on the sandy bottom. The Fiddler Ray (or Guitar Shark), a species halfway between a ray and a shark, are also regularly encountered. Southern Eagle Rays are a shy species, and a rarer sighting in Jervis Bay. One of the most interesting ray species in the area, the Numb Ray, are also found both during the day and night. But don't get too close - their electric shock is not one to be played with!
Outside the heads of the bay, there are two seal colonies, at Drum and Drumsticks and Ellisa's Playground. These colonies are a mix of both Australian Fur Seals and New Zealand Fur Seals, both of which are found at these haul outs all year round. However, weather conditions make April to December the best time of year to dive with these colonies.
Approximately 40,000 Humpback Whales migrate along the east coast of Australia, and their population continues to grow. Coming from the cold feeding grounds in the Antarctic, they make their way towards warmer waters for breeding. Along the way, they show off a constant stream of 'acrobatic' behavior - breaching, fin-slapping and tail slapping all the way up and down the coast.
Exciting encounters of rarer species include the Southern Right Whale. An endangered species that is easily distinguishable by its short pectoral fins and large white callosites on their heads.
Jervis Bay is home to nearly 100 resident Bottlenose Dolphins. Found in groups of anywhere from just one or two, to over 40 individuals, they travel in nursery pods, family groups and bachelor pods.
Outside the heads, the Common Dolphin can be found in huge pods of 20 - 30, to hundreds and thousands of individuals! Easily identified by their slightly yellow hourglass marking, and often feeding alongside Australasian Gannets.
Even though they are called Killer Whales, Orcas are actually a member of the dolphin family. On the very rare occurrence, they are spotted off the coast of Jervis Bay, usually alongside the whale migration...
While many are familiar with the turtle filled waters of warmer waters, it is often not realised how many turtles are found in cooler waters including Jervis Bay. Originally named the Green Turtle by fisherman, not because of their appearance, but after the colour of their flesh, many Green Turtles find solace in and around the bay. They are distinguished from other turtles by their small round head, large front flippers and number of scales on their carapace (shell). Check out our Turtle Tracker project to see recent sightings of Green Turtles within Jervis Bay!
Hawksbill Turtles are less regularly seen, however also reside within the bay. Readily identified by their large hawk like bill, their pointed jaws are well adapted for prying food from crevices in and around coral, however also consume seagrasses, algae, sea cucumbers and shellfish.
Unlike the Green Turtle and Hawksbill Turtle which reside in the bay, the remarkable Leatherback Turtle is a pelagic (deep water) species that migrates through the area. A sighting of these incredible marine turtles is a very lucky one. Unlike other common turtles, they have thick black leathery skin with five ridges that run along their back. Make sure to report a sighting if you are lucky enough to see one!
Cephalopods are one of the most interesting group of marine creatures, and we have an incredible range of species in Jervis Bay.
Gloomy Octopus (Sydney Common Octopus): Although common, this species is one of the most interesting to encounter underwater. Most often seen hiding within their dens, armored with discarded shells, these octopus are extremely intelligent, curious and often playful. With their inquiring tentacles, impressive colour changing abilities, and so much more - they are truly unbelievable creatures.
Blue Lined Octopus: Only 5cm, and often extremely camouflaged, these tiny octopus have enough venom to kill 10 people. A member of the Blue Ringed Octopus genus, they only show their bright blue markings when agitated or excited, and can often be mistaken for another species of juvenile octopus.
Giant Cuttlefish: One of the most sought after being the Giant Cuttlefish. While they can be seen year round, they are most often seen around the winter months during breeding season. They are the largest cuttlefish in the world, and their curiosity, shape shifting talents and colour changing abilities make them one of the most exciting animals to see.
Reaper and Mourning Cuttlefish: While a lot smaller than their larger Giant Cuttlefish cousin, they are no less mesmerising. Although they look very similar, Reaper Cuttlefish have a yellow tinge under the eye, whereas Mourning Cuttlefish have a blue tinge.
Pyjama Squid: Although they are only small, approximately 10cm in length, this small cuttlefish packs a punch! Being one of the only species that is both venomous and poisonous, of which it is said that it's pyjama like stripes are a signal.
Eastern Blue Devil Fish
This shy and secretive fish is always an exquisite sight to see. Still threatened by poaching for aquariums, and a history of targeted spearfishing - this species is now heavily protected.
Often occupying rocky overhangs, small caves and ledges, they are a solitary species and usually timid. However, in their breeding season pairs can be observed, which are often much braver and if you're lucky, you can also witness courtship behaviour.
Weedy Sea Dragon
The Weedy Sea Dragon is a member of the Sygnathidae family, a relative of other sea dragons, pipefishes and seahorses.
Often much larger than people initially imagine, these Sea Dragons can reach up to 46cm. Their camouflage is almost impeccable, replicating the golden kelp they are usually found in. However, under sun or torch light, their bright purple stripes and yellow spots are a beautiful giveaway. If you're lucky, you'll catch the males carrying their bright purple eggs along their tail.
Not very shy, this species presents a great photographic opportunity for divers, and scientists alike! As their spots are unique to each individual, photos are often used by citizen science projects such as SeaDragon Search.
Nudibranchs and Other Sea Slugs
These colorful sea slugs are incredibly diverse, and are an underwater macro photographers ideal subject.
The name nudibranch, means naked gills, describing the branchial gills in the shape of a rosette found on the backs of most nudibranchs.
As diverse as their colours are, so are their lifestyles, behaviour and physiologies. For example, the 'Blue Dragon' (Pteraeolidia ianthina) (pictured left) resembles a purple chinese dragon. This nudibranch eats hydroids and farms the derived algae in its cerata, so that they continue to photosynthesise and the nudibranch gains the sugars made from the process. Some nudibranchs can be identified by the algae they are found on, others are cannibalistic, and others poisonous to predators that may consume them!
Seahorses and Pipefish
Jervis Bay is lucky enough to be home to a wide variety of Sygnathidae species, although they might not always be so easy to see.
This seahorse is the largest species of seahorse in the world, but it does not make them easy to see! They have been seen clinging to golden-kelp or sea tulips, as well as man-made structures. Just like other seahorses, the male carries the eggs inside a pouch, and can give birth to hundreds of young at a time.
This pipefish can grow up to 25cm and can be seen lying on the sandy bottom. However, even when laying exposed on white sand, it remains hidden from potential predators (and divers) as they are perfectly camouflaged, looking more like decaying seagrass, algae and detritus.
Named the upside-down pipefish because of their unusual behavior, they are often seen clinging to the underside of small crevices, ledges and caves, usually in pairs. They only grow up to 10cm, and are often spotted first by their spiky tail fin.