Nick Piekarski. Rapid Bay Dive Site Report

Leafy Seadragon, (Phycodorus eques). Endemic to southern Australian waters, it is the aquatic emblem of South Australia. Many divers have not seen them but have no problem at Rapid Bay as the following report suggests.

One jetty among all stands alone - Rapid Bay. This particular site is overwhelming, even after many years it never ceases to amaze; gin clear water is usually the case and although surge is sometimes present it is never threatening. A sandy bottom, underneath most of the jetty, surrounded by lush green sea-grass is proof of a healthy environment. Situated on the north western coast of the Fleurieu Peninsula, Rapid Bay is the most southerly accessible jetty dive within easy reach of metro Adelaide. It sources life from the wild and tumultuous Southern Ocean and everything and anything can show up there. During the cooler months, copious quantities of Leafy Sea Dragons (Phycodures eques) can be found on the seaward side of the T-section and many are of impressive size. As you swim towards the centre you soon realise what makes Rapid Bay special, the amount of fish life is awesome. Everywhere you look you are bombarded by countless varieties of marine life, some stand out immediately while others meld slowly in to complete the big picture. Large schools of Pike, Tommy Ruff and Yellowtail are always present, continuously moving about between one another on endless sojourns.

Paul Groves, Underwater World, Perth.

Tony Flaherty — Marine & Coastal Community Network/Dragon Search (SA)

Usually leafy seadragons are found only individually or in pairs in the wild. In captivity they are very sociable and frequently huddle together in groups of up to four individuals, all with fins entangled in each others. With the approach of spring, male and female seadragons form pairs. Once paired, both seadragons keep close together, sometimes entangling fins together but very rarely moving away more than one metre from one another in their search of food. Once this initial pairing has formed, the seadragons begin their preparation for breeding. The female leafy seadragon starts to develop around 300 orange eggs within the lower abdominal cavity. As her eggs develop, she develops a very wide girth in the vicinity of her second pair of ventral fins and down through to her anal fins. Just before the release of eggs, her anus enlarges to several times its normal size. During this period the male also goes through some transformations. As the eggs begin developing in the female, the tail of the male begins to swell in size and become wrinkled. Fine blood vessels can be seen forming in the tail also. Once the tail is swollen and wrinkled about 120 small pits or egg cups begin to appear on the tail in preparation for the receipt of the eggs. pits on the swollen tail of a male dragon whilst in the company of a female are a good indicator of impending egg transfer. During the weeks that these changes are occurring, the male leafy seadragon can often be seen ‘displaying’ to the female. He will swim along side of her in a distinct ‘head up head down style’ type of swimming motion. Sometimes she will reciprocate with a similar motion. Occasionally he will approach the female front on in an upside down position, as if to show off his readiness to reproduce. The male also becomes very protective of the female during this period and will aggressively chase away any other males that come too close. He also attacks with an aggressive ‘snapping’ of the jaws, as if he is trying to bite the fins of the offending male, although the lack of teeth usually prevents any damage occuring to the other male.

Females transfer their eggs to the males’ tails for incubating around September to December. They are attached to pits on the underside of the male’s tail in a process that usually totally exhausts the female. It is theorised that the eggs may derive some nutrition from blood vessels in the tail of the male. Male leafy seadragons are seen carrying eggs during the spring and summer months. The young juveniles hatch out with a small yolk sac, and are free swimming almost straight away. They usually start hunting for small items of food almost immediately. Young Dragons are fast growing and may be old enough to reproduce by the following summer.