The Structure and Distribution of Coral Reefs noted the location of the different types of coral around the reef and in the lagoon. In his diary, he described, "examining the very interesting yet simple structure & origin of these islands. The water being unusually smooth, I waded in as far as the living mounds of coral on which the swell of the open sea breaks. In some of the gullies & hollows, there were beautiful green & other colored fishes, & the forms & tints of many of the Zoophites were admirable. It is excusable to grow enthusiastic over the infinite numbers of organic beings with which
Coral Sea whitetip reef shark ("Triaenodon obesus", 21%), silvertip shark ("Carcharhinus albimarginatus", 10%), tiger shark ("Galeocerdo cuvier", <1%) and great hammerhead ("Sphyrna mokarran", <1%). The interaction rate (free diving) at the Coral Sea reefs ranged from a few to 26 sharks per hour. The rare "Etmopterus dislineatus" shark species is endemic to the central part of the Coral Sea. It has been observed at depths of 590–700 m on or near the continental slope. The coastal areas of the Coral Sea were populated at least 40,000 years ago by prehistoric people descending through the northern islands. Those Aboriginal tribes have been dispersed