Ecology

Jervis Bay is enclosed by two rocky peninsulas; Beecroft in the north and Bherewerre at the south. On the seaward side is a line of sheer cliffs which not only tower above the sea to a maximum of 135 metres north of Steamers beach ( the highest in N.S.W.), but also plunge to a depth of up to 40 metres straight down with no intervening rock platform. This great wall follows the line of the Pt Perpendicular wall on the north side which also extends around the entrance to the bay. As a landscape these walls are geologically unique with a complex combination of structural warping and faulting of Permian rock strata, followed by post glacial flooding by the ocean. The syncline warping of the 230-280 million old Permian sandstone forming a saucer shaped depression in the earths crust evidence of this can be seen at Vincentia and Beecroft peninsular. The seawalls have great diversity of form and feature,. The comb-like profiles were sculptured by the searching wind, rain and relentless sea weathering the alternate harder and softer layers of sandstone.

The rocky shores of Bowen Island , Pt Perpendicular and Bherewere shorelines extend to deep submerged reefs of 25 - 40 meters depth , they are festooned with sea life of bewildering variety and beauty. With the might of the sea , the rugged coastline the area is classed as being one of the great coasts of Australia.

The richness of the bay's plants, animal life and crystal clear waters makes it a divers, snorkelers and photographers delight. Divers describe it as like descending into a wonderful life size aquarium. The underwater habitat includes weed covered and bare shallow rocky reefs, sand zones, seagrass meadows, sand deltas, cliff platforms, blocks, boulders, many swim throughs and caves.

Wetlands Jervis Bay wetlands are comparatively small in relation to the size of the bay, however these wetland are important as they are the breeding grounds for fish that are essential to maintain stocks in the bay. Wetlands also provide habitats for water birds. crustaceans, mulluscs and a nursery for other marine species.

Sea grasses in the Bay grow at deeper depths than elsewhere on the east coast. The seagrass beds cover an area of 906 hectares and contain examples of all seagrass species found in N.S.W. The largest area of posidonia Australis in Australia is located in the Bay. Sea grasses help stabilise the seabed and are an important part of fish nurseries.

Mangroves The Bay contains two species of mangroves. The grey mangrove avicennia Marina and the river mangrove aegiceras Corniculatum, they both cover 12.5 hectares of the bay area, predominantly at Moona Moona creek ,Currambene creek, also at Cabbage Tree creek, Wowly Gully, Callalh creek and Carama inlet on the north eastern corner of the Bay.

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Flora & Fauna. Jervis Bays marine habitat support an extremely rich marine fauna including some 200 species of fish ,also invertebrate animals such as sponges , hydroids , bryozoan , masses of sessile animals , molluscs , crustaceans, worms , anemones nudibranchs .Weedy sea dragons abound as well as seahorses. Stingrays reside and have been recorded up to 2 meters wide

Dolphins abound living and breeding in the Bay ,their numbers are unknown , but at least 60 recognisable individual resident bottlenose Tursiop dolphins are evident. Nomadic common Delphinus dolphins also visit the Bay on a regular basis in large pods of over 100.

Seals can also be seen frolicking on the surface ,cooling themselves by holding their flippers above water. These individuals have ventured from their colony located near Steamers beach.

Whales visit the Bay , as they migrate North in Autumn and South in Spring ,often bringing their new born calves in for rest.

Records show that over 200 bird species inhabit around the area including many endangered species. The Ground Parrot and the Eastern Bristle Bird. There are about 2000 Eastern Bristle Birds in Australia, about 600 of them in the Jervis Bay area. Peregrine falcons are found on the bay's high cliff faces, these birds swoop down on their prey with a speed in excess of 300km/hour stun them then catch them before they hit the water or ground. White Breasted Sea eagles can be seen regularly patrolling the beaches of the bay in search of food. The Sooty Owl, Barking Owl & Southern Logrunner frequent the Bay's rain forests. 38 different species of mammals and reptiles including the rare Broad Headed snake and the Jervis Bay frog ,the Large Footed Mouse-eared Bat ,the new Holland Mouse and the Diamond Python. There exists a unique mix of flora species having their northern and southern boundary limits in Jervis Bay (some of these can be seen in the Botanic gardens in the national park). The Bay's vegetation is varied and ranges from small patches of rain forests, the largest on the western slopes of Beecroft peninsular to the woodlands which has no less than 30 different species, ( some 30 metres high) mainly eucalypt, redwood, blackbutt, swampy mahogany , lillypili while the dunes are covered in lillydilli wattle, teatree and banksia ,waratah ,heath and many other native species.

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Lagoons The two fresh water lagoons ,Lake Windermere and Lake McKenzie both have deep layers of sediment contains diatoms ,pollen spicules and skeletons of aquatic fauna. They provide evidence for scientists to reconstruct past environments of the region ,as well as valuable habitat today for water fowl and aquatic animals.

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