The Marine Parks of Johor have two distinct regions, the inshore
islands are Pulau Rawa, Pulau Babi Hujung, Pulau Babi Tengah, Pulau Babi Besar, Pulau
Tinggi, Pulau Mentinggi and Pulau Sibu. Easily accessible, they are popular with
non-divers and snorkellers, so they are very busy over weekends and holidays. The
underwater visibility rarely exceeds 20m this close to the mainland because of river
Offshore, 65km east of Mersing, Pulau Aur, and the three smaller islands of Pulau
Dayang, Pulau Lang and Pulau Pinang, together with Pulau Pemanggil which is 15km
northwest of Pulau Aur, make up the rest of the Johor Marine Park. Most of the rocky
islands are well forested and have isolated coconut plantations. With deep, clear
water, healthy corals and regular encounters with large pelagic species, these islands
have the potential to become international diving locations.
Several underwater Pinnacles on the east side of Pulau Aur rise 30m from the sea
floor to within 10m of the surface with good hard coral growth including undamaged
table corals (Acropora Sp.). 'Rayner's Rock' northeast of Pulau Dayang, is
a similar 33m high, submerged rock where there are impressive Boulder Corals (Porites
Sp.), Whale Sharks have been seen and delightful encounters with large Manta
Rays (Manta birostris) are common.
It is surprising to see extraordinarily large numbers of juvenile fish this far offshore,
many are so different in shape and markings from their adults that they can be mistaken
for different species.
When fish are ready to breed, many strategies have evolved to ensure that only the
strongest males and females mate. In some species, the presence of Alpha (larger)
females prevent smaller fish becoming females. With many other species males fight
to establish domination. With so many fish of similar shapes living in close proximity
on crowded reefs it would be a waste of energy if adults picked unnecessary fights
with juveniles. One way to avoid this happening is for juveniles to be a completely
different colour, pattern or shape from mature adults.