Australian Angelshark

Angelsharks grow from 13cm at birth to 152cm in adulthood.

They live in in the subtropical waters of southern Australia from Western Australia to New South Wales, at depths down to 255 metres.

Angelsharks have extensible jaws that rapidly snap upwards to capture prey; they have long, needle-like teeth. They bury themselves in sand or mud lying in wait for prey, which includes fish, crustaceans, and various types of mollusks. They can produce litters of up to 20 pups.

Australian Fur Seal

The Australia fur seal is an amazing swimmer and diver, reaching in excess of 150 metres deep in search of its food.

The fur seal also has carnivorous teeth and long whiskers that it uses to find its food. The Australian fur seal’s diet consists of squids (its favourite!), octopus, crustaceans, rock lobsters, and small fish. It usually hunts schools of fish made up of pilchards or mackerel. This seal is also very talented at getting fish off of a fishing line to the surprise of the fisherman.

The Australian fur seal, arctocephalus pusillus, is the largest of all with large eyes and a pointed face. It has a broad head, pointed snout and long backward sweeping facial vibrissae (whiskers). The body is robust and covered in thick brown layered hair except on the front and back flippers.

The Australian fur seal is sexually dimorphic (males and females are visibly different). The males are larger than females and when mature carry a dark mane of coarse hair. They have a set of carnivore-like teeth similar to those of a large dog or bear. Like all members of the family otariidae (fur seals and sea lions) they can raise their body onto their front flippers to move around on land.

It is the world’s fourth-rarest seal species but was hunted to the brink of extinction last century. Population recovery has been slow and the seals are now wholly protected. The Australian fur seal is found around the coast of NSW, via Victoria, around Tasmania to South Australia.

Australian Giant Cuttlefish

Despite their common name, cuttlefish aren’t fish, but cephalopods in the mollusc family (which includes octopus and squid).

The giant cuttlefish is among the biggest in the world, growing to a whopping 1 metre and weighing up to 10kg. They have two methods of swimming. When speed is required the cuttlefish utilises backward jet propulsion by sucking water into their body then forcefully ejecting it through a funnel. Otherwise they swim by hovering with gentle undulations of their lateral fins (often referred to as a skirt).

While stalking fish and crabs the skin changes colours – tiny elastic pigment sacs expand and contract plus the raised skin flaps help it change texture for a more effective camouflage. Two long tentacles shoot out in a whip like motion to seize the prey, then the other ‘arms’ are used to immobilize it for consumption. The giant cuttlefish hunts other smaller molluscs, including other cuttlefish, as well as shrimp and crabs. Hard shells pose no problem for the bird like beak hiding among the many tentacles nor their tooth lined tongue.

Mating season is the start of winter and larger males will guard smaller females during this frantic time. As a result males can become highly territorial and aggressive. Sadly all this energy spent in breeding and laying eggs means once the season is over most cuttlefish die. The eggs are individually laid in their protective onion-shaped casings and attached to the underside of flat rocks in tight spaces. The average lifespan is 2 to 3 years and as a consequence you will most often spot the giant cuttlefish resting as it channels most of its energy into growth.

Known to be highly inquisitive and attracted to bright colours it’s not uncommon to see them following divers.

Banded Coral Shrimp

Banded coral shrimp are the largest known cleaner shrimp.

They are also called “boxing shrimp” because of the large pinchers on their third set of legs. They often hold these pinchers erect giving the appearance of a boxer ready to fight. They have three antennae which are two-and-a-half times bigger than the shrimp itself.

They are usually found in pairs which mate for a lifetime. The male banded coral shrimp is usually noticeably smaller than the female of the species. The female can also be recognized by the presence of greenish ovaries visible through the transparent carapace. Mating can only occur when the female is molting. After mating the female holds onto the fertilized eggs under her abdomen which hatch after 16 days. After hatching the larvae remain with the female for a few weeks and become planktonic. They undergo seven stages before becoming an adult.

Lost limbs are regenerated quite easily during the next mould. The banded coral shrimp may live 2-3 years, sometimes longer. They like to live in small crevices and discarded man-made objects – like tires and buckets. They are very territorial and occupy territories of 1-2 metres in diameter; other crustaceans are not accepted within their territory.

They remove then eat parasites, injured tissues, and undesired food from a variety of reef life. They can be seen from their crevice although the shrimp remains hidden unless to lure fish in need of cleaning. To let fish know when it wants to clean, it will be seen dancing to attract attention.

Bat Ray

Bat rays can grow a wing span of 1.8 metres and weigh up to 90kgs (although they typically range from 9.07 kg-13.61 kg.)

They live in a wide range of environments. They mostly eat mollusks, crustaceans, and small fish that lay on the seabed. These rays use their wing-like pectoral fins to move sand and expose both prey and prey animals. They do have a poisonous spine on their tails but only use it as defense when scared.

Bat rays can live up to 23 years. They mate annually, in the spring or summer, and have a gestation period of nine to twelve months. Their litters can contain 2-10 pups. When the pups emerge, their pectoral fins are wrapped around the body, the venomous spine is flexible, and covered in a sheath which sloughs off within hours of birth.

Bigscale Bullseye

The bigscale bullseye is pale to dark brown or silvery with thick brown stripes along the scale rows.

The fins are dusky. Juveniles are paler with black-tipped and yellow pelvic fins. It is a deep-bodied, compressed species with a very large eye, and a large oblique mouth. The bullseye live in temperate waters of southern Australia. They are a common fish found in large schools on rocky reefs in depths from 4 to 30 metres. They grow to approximately 22cm. They feed on plankton, small crustaceans, and cephalopods. This species usually shelters in caves and ledges during the day, venturing out at night to feed.

Blue Groper

The word “groper” comes from the word for the fish, most widely believed to be from the Portuguese name, ‘garoupa’.

Gropers are teleosts, typically having a stout body and a large mouth. They are not built for long-distance or fast swimming. They can be quite large with lengths over a meter and weights up to 100kg not uncommon; though obviously in such a large group, species vary considerably.

They swallow prey rather than biting pieces off it. They do not have many teeth on the edges of their jaws, but they do have heavy crushing tooth plates inside the pharynx. They habitually eat fish, octopus, crab, and lobster.

Most fish spawn between May and August. The young are predominantly female but transform into males as they grow larger. They grow about a kilogram per year. Generally they are adolescent until they reach three kilograms, when they become female. At about 10 to 12kg they turn to male. Usually, males have a harem of three to fifteen females in the broader region. In the rare case that no male exists close by, the largest female turns faster.

Blue Swimmer Crab

The blue swimmer crab is a tropical species of crab that has acclimatized to the cooler conditions of southern Australia.

They are found in lots of different places but they prefer sandy bottoms and sea grass meadows. Swimmer crabs are distinguished by the fact that their last pair of legs are swimming paddles.

They bury themselves leaving only their eyes, antennae, and gills exposed. They stay buried under sand or mud most of the time, particularly during the daytime and winter. They come out to feed during high tide; on various organisms such as bivalves, fish, and, to a lesser extent, macroalgae.

To mate the male swimmer crab will court a female for four to ten days – this is done by carrying her underneath him. After spawning, the larvae go through lots of different stages before taking on the adult shape.

Bottlenose Dolphin

Bottlenose dolphins are the most common type of dolphin.

They inhabit warm and temperate waters all over the world. They live in pods of ten to thirty members although group sizes can vary dramatically from one to more than one-thousand!

Dolphins often work together to hunt schools of fish. They enjoy small fish, crustaceans, and squid. They search for prey by using echolocation which is similar to sonar. They make clicking sounds and listen for the echo to work out the location, shape, and size of nearby items. They also use this clicking for communication as well as whistles from their blowhole, sounds through body language, leaping through the water, and slapping their tails on the water.

Dolphins are extremely intelligent, they are popular in aquarium shows, television programs, and are even trained by the military to detect sea mines or to detect and mark enemy divers. Adults range from 2 to 4 metres in length and weigh between 150 and 650kgs. Males are on average slightly longer and heavier than females. They live to around 40 years. Births occur all year round however it is more common in the warmer months. Females usually give birth to one pup every two to six years.

Boxfish

The hexagonal plate-like scales of these fish are fused together into a solid, triangular, box-like carapace, from which the fins and tail protrude.

Young boxfishes are more round in shape and may exhibit bright colors. Because of their body scale structure, boxfish are limited to slow movements.

The boxfish are a family, ostraciidae, of squared, bony fish belonging to the order tetraodontiformes – closely related to the pufferfish and filefish. They come in a variety of different colors, notable for the hexagonal or “honeycomb” patterns in their skin and skeletons. They swim in a rowing manner. Fish in the family are known variously as boxfish, cofferfish, cowfish and trunkfish.

Brittle Star

Brittle star crawl across the seafloor using their flexible whip like arms which can reach a length of 60cm in the larger specimens.

Different types of brittle star live in an abyssal depth of deeper than 6,000 metres. They are common in reef communities where they hide under rocks.

They are generally scavengers but may also prey on small crustaceans or worms. Brittle star become fully grown in three to four years and can live up to five years. They, like lizards, can shed their arms to escape predators then regenerate them; it can also regenerate its stomach.

Eastern Blue Devil

Commonly regarded as one of the most beautiful reef fish in NSW, this shy and secretive species is of low abundance due to natural rarity.

Its population was further harmed by over hunting and collection by humans making it now fully protected under NSW Fisheries Laws. Blue Devils are found in 3 to 30 metres of water and prefer to reside near caves, crevices, and rock ledges – where they hang out during the day. If approached by a diver, or overzealous photographer, they tend to move into the back of the overhang to remain safe.

The breeding season is from October to March, and males are thought to defend a territory with a promising overhang in order to attract a mate. The female then lays groups of bright yellow eggs and glues them to the roof of the cave, or ledge, until they hatch. 4mm long, free-swimming larvae wriggle out and settle around nearby reef areas. There have been very few sighting of juveniles but when fully grown Blue Devils can become as big as 40cm. They delight in eating brittle sea stars.

They have been known to reside in the same cave over several years and are thought to be more active at night. Usually sighted individually or as part of a mated pair, we are proud to say that our local dive site Blue Devil Cave has been a host to these photogenic beauties for many years now.