FISHERY BULLETIN: VOL. 71, NO. 4 



I I I I I I I I I 

 5 10m 



Figure 2.— Schematic diagram of Pink Cliff study area, Isla Partida, showing the relative positions and movements of the 

 nine tagged Acatuhaster ellisii during the 48-h study period. Depth of water at the interface between hard and soft bottoms 

 is about 10 m. 



Daytime underwater visibility in 1970 was 

 about 20 m; in 1971, it varied between 6 and 

 15 m. Night visibility was reduced by swarms 

 of mysids, polychaetes, and larval fishes which 

 concentrated in the beams of our hand-held 

 lights. Water temperatures were 27 °C during 

 the fall visit, 18°-21°C in the spring. 



The Coral Fauna 



Pocillopora is the conspicuous coral, al- 

 though there are less than 20 large heads; the 

 majority stand as scattered individuals in the 

 "coral garden" near the cliff base in the north- 

 east part of the platform. Several are inhabited 

 by hawkfish (see Figure 3) and anomuran crabs. 

 A few small Pocillopora grow on the lower 

 vertical surfaces of the cliffs and monument 

 rocks. Scattered small colonies of the den- 

 drophyllid coral, Tubastrea aurea, are restricted 

 to the deeply shaded sides of the monument 

 rocks and cliff walls. 



The large number of small encrusting Pontes 

 californka contradicts the first impression of a 

 sparse coral fauna. In the deeper regions, these 

 scablike coralla (see Figure 4) are about 4-5 cm 

 in diameter and well separated from one ano- 

 ther; with increasing height, they become pro- 

 gressively larger and less regular in outline, 

 encrusting the pits and crevices, or covering 

 small protuberances to form knobs. 



The abundant Pontes on the cliff face is so 

 highly irregular in outline that it was impos- 

 sible to distinguish individual colonies, but we 

 attempted to count the coralla within a 0.5 m- 

 diameter ring placed in five locations on each of 

 two transects along the platform. Numbers 

 increased from 50 coralla/m- on the seaward 

 edge of the platform to 100 coralla/m- at the 

 cliff base. In the surge shadow cast by a 3 m- 

 high rock, and on the adjacent region of the 

 platform which is protected from surge by the 

 reef, there were as few as 10 coralla/m-. 



932 



