It's this marine life that makes the area a very popular destination for scuba divers to visit and enjoy and the protection provided by the marine park is to the benefit of these species.

The offshore islands of the marine park are renowned diving destinations with local dive boats visiting them on a daily basis.

The most popular location is Broughton Island that has resident Grey Nurse sharks at several sites whilst the 'Looking Glass' is a must do dive site and is spectacular when the sun is shining and water is clear.

Looking Glass also has resident Blue Devilfish and if one is fortunate, they may even come across the protected Weedy Seadragon.

North Rock is another great boat dive at Broughton Island and is the best location to see the endangered Grey Nurse shark and also has extensive sponge gardens below 18m where the protected Elegant Wrasse can be found.

Another popular island for diving around is Cabbage Tree Island located just outside the Port Stephens heads.

The Little Wreck is a protected dive site from winds and swells and the remains of two old boats have become home to a variety of fish including wobbegongs, flathead and blue gropers.

This is also the site to look for the rare but spectacular Donut Nembrotha nudibranch and the Red Indianfish.

Other dive sites around Cabbage Tree include the wreck of the SS Oakland. Boondelbah and Little Island nearby provide a good alternative option.

Port Stephens is considered to have the best shore diving in all of Australia with several well-known dive sites found in the Nelson Bay area.

The dive sites are commonly known as Halifax Park, Little Beach, Fly Point, Seahorse Gardens and the Pipeline. Each site is uniquely different.

Halifax Park

This site has strong tidal currents so it's important to dive on slack high tide.

This site experienced a large sand inundation event in 2010 which changed the dynamics and habitats of the site.

There is now a lot of sand built up across this site but in among the sand there are large bommies to be found covered in sponges and marine life.

It's these outcrops that are the best spots to dive as all the fish congregate around the sponges as well as green and sawtooth morays, blue groper, tusk fish, nudibranchs, schools of bullseyes and just so much more!

Little Beach

This site is becoming more popular to dive as a result of limited park availability at Fly Point.

Enter the water between the two jetties at the western end of the beach and swim towards Fly Point at a depth of about 9m.

You will come across the sunken barge and A-Frame at 12m which are covered in fish and it's usually a good location to find a turtle.

Also, under the southern section of the barge there is a colony of Pineapple fish and this is one of the more reliable spots in the bay to find them.

Fly Point

Best location to visit is the 'ledges' which can be found around 11m to the north-west of the entry point.

Species to look for include the pineapple fish and the tame Maori cod and Fly Point is also a great place to find nudibranchs.

A completely different type of dive can be found if you swim towards the east and keep to a depth of 8-10m you will find unusual species such as walking gurnards, striped pyjama squid, pipefish and the occasional seahorses.

This site has been protected from fishing since 1983 and hence the fish life is incredibly abundant and diverse.

If you are feeling adventurous, hop in the water about 1 hour before the high tide and do a leisurely drift dive around to the west and exit at the Seahorse Gardens dive site.

Seahorse Gardens

This site was initially named for the abundance of the endangered White's seahorse that previously occurred here.

Unfortunately, as a result of a large decline in the endangered cauliflower soft coral at this site, seahorses are now rarely seen here.

The site still is a good spot to search for small macro critters such as nudibranchs, octopus, Bobbit worms and pyjama squid.

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It's also a very good site to find anglerfish, a sought-after fish by underwater photographers.

The best time to scuba dive this site is approximately 2 hours before high tide and you enter the water in front of the toilet block at the Fly Point end of Nelson Bay main beach.

Stick to a depth of 8-10m and head in a southerly direction towards the marina .

Pipeline

Back in 2010, the Pipeline was recognised as one of the best shore dives in the world but unfortunately a lot has changed over the past decade at this site.

The cauliflower soft corals, once prolific at this site, have all disappeared and hence the White's seahorse is not as common here anymore as they don't have the habitat to live on.

However, it's still probably the best location in the bay to find unusual critters and after a 90-minute dive you can leave the water scratching your head at all the critters you have just seen.

This is the site where rare and unusual species can be found such as the velvetfish, the blue ringed octopus and the elusive Nelson Bay anglerfish.

The best area to find the marine critters is now on the western side of the old sewage pipe searching around the sponges at a depth of 7-10m.

Don't forget that you are diving within a marine park so the taking and harming of marine life is prohibited so please ensure you respect and look after the marine environment.

Dr David Harasti is a senior marine scientist with the NSW Department of Primary Industries Fisheries, based at Taylors Beach.

To showcase the Port's incredible underwater world the Examiner has collaborated with regular Nelson Bay divers and photographers on a series that explores life Beneath the Surface.