TABLE 1. Summary of Biological Observations made at Transect T-1 on the Mokapu Ocean Outfall Diffuser on 
27 July 1998. (Sampling began at the main stake marking this transect and continued in a seaward direction.)


Percent Cover
I. Quadrat Survey

Quadrat Distance Along Transect


0 m
5 m
10 m
15 m
20 m

Algae





Porolithon onkodes 
12.0
4.0
15.0
3.0
9.0
Peyssonellia rubra (?)
9.0
15.0
8.0
7.0
14.0






Hydrozoans





Halocordyle disticha 



1.0







Bryozoans





Reteporellina denticulata 


1.1
1.5







Corals





Porites lobata
39.0

7.0
17.0
17.0
Porites compressa 
0.3










Rubble

12.0



Hard Substratum
39.7
69.0
68.9
70.5
60.0


II. Macroinvertebrate Census (4 m ? 20 m)
No. of 
Individuals





Phylum Annelida

Loimia medusa
1


Phylum Echinodermata

Echinometra mathaei 
3
Echinothrix diadema 
27
Echinothrix calamaris 
6
Heterocentrotus mammillatus 
2

   
III. Fish Census (4 m ? 20 m)






34 Species





1,481 Individuals





Estimated Standing Crop = 1,124 g/m2






NOTE: Results of the 5-m2 quadrat sampling of the benthic community are presented in Part I as percent cover, counts of 
diurnally exposed macroinvertebrates are given in Part II, and a summary of the fish census is given in Part III. Water depth 
is 29.6 m; mean coral coverage is 16.1% (quadrat method).



1
