COMMUNITY STRUCTURE OF FISH AND MACROBETHOS
AT SELECTED SITES FRONTING SAND ISLAND, OAHU,
IN RELATION TO THE SAND ISLAND DEEP OCEAN OUTFALL,
DECEMBER 1991 SURVEY





Richard E. Brock






Special Report 04.30:92








August 1992







PREPARED FOR
City and County of Honolulu
Department of Public Works
Project Completion Report
for
The Assessment of the Impact of Ocean Outfalls
on the Marine Environment off Oahu, Hawaii
Project No.:  C-59390
Project Period:  27 December 199031 December 1990
Principal Investigator:  Roger S. Fujioka


WATER RESOURCES RESEARCH CENTER
University of Hawaii at Manoa
Honolulu, Hawaii  96822

ABSTRACT
This report constitutes the second year of an annual monitoring (carried out on 56 
December 1991) of shallow marine communities inshore of the Sand Island deep ocean 
outfall. This quantitative monitoring effort focuses on benthic and fish community 
structure and is designed to detect changes in these communities. Marine communities 
offshore of Honolulu have received considerable perturbation over the last 100 years. 
Raw sewage was dumped in shallow water until 1978; point and non-point sources of 
pollution from both urban sources and industry continue. All of these disturbances may 
serve to obscure any possible impacts from the deep ocean outfall discharge. The marine 
communities show a considerable range in development that is probably related to past 
(historical) impacts. Stations have been sited to take advantage of these gradients. 
Analysis of the first years data show that there has been no statistically significant 
change in the biological measures quantified in this study. These measures include the 
percent coral cover, number of coral species, number of invertebrate species, total 
number of invertebrates counted, number of fish species, total number of fishes counted, 
and the biomass of fishes present at each station. Thus, in this second year, there has not 
been a quantitatively discernable impact to the shallow water benthic and fish 
communities that could be attributed to the operation of the deep ocean outfall.

INTRODUCTION
Purpose
In recent years controversy has arisen regarding the impact that sewage effluent from the Sand Island 
Wastewater Treatment Plant may have on inshore coral reef species. Much of the geographical area of 
concern in this study was impacted by the release of 3 m3/sec (62 mgd) of raw sewage in 10 m of water off 
Sand Island from 1955 to 1977. Starting in 1978 sewage received advanced primary treatment and was 
released further offshore of Sand Island from a deep ocean outfall (6773 m depth). Despite studies that 
demonstrated the recovery of inshore benthic communities once the shallow sewage stress was removed 
(e.g., Dollar 1979), concern continues over the possible impact that the release of sewage from the deep 
ocean outfall may be having in the shallow (< 20 m) marine communities fronting Honolulu and Sand 
Island. Accordingly, this study was undertaken commencing in 1990 in an attempt to quantitatively 
ascertain the impacts that may be occurring. This document presents the results of the second annual 
survey, carried out in 1991.
Strategy
Marine environmental surveys are usually performed to evaluate feasibility of, and ecosystem response to, 
specific proposed activities. Appropriate survey methodologies reflect the nature of the proposed action(s). 
An acute potential impact (as channel dredging) demands a survey designed to determine the route of least 
harm and the projected rate and degree of ecosystem recovery. Impacts that are chronic or progressive 
require different strategies for measurement. Management of chronic stress to a marine ecosystem demands 
identification of system perturbations which exceed boundaries of natural fluctuations. Thus a thorough 
understanding of normal ecosystem variability is required in order to separate the impact signal from 
background noise. 
The potential impacts confronting the marine ecosystem offshore of Sand Island and 
Honolulu Harbor are most probably those associated with chronic or progressive stresses. 
Because of the proximity of the population center and industry, marine communities 
fronting Honolulu Harbor are subjected to a wide array of impacts not usually occurring 
in other Hawaiian coral communities. Thus a sampling strategy must attempt to separate 
impacts due to wastewater treatment plant effluent on coral reef communities located at 
some distance shoreward, from a host of other perturbations occurring in the waters 
fronting Honolulu.
Honolulu Harbor has been the primary commercial port for the State of Hawaii since 
before the turn of the century (Scott 1968). The harbor is the result of dredging what was 
originally the drainage basin of Nuuanu Stream. This dredging commenced before 1900 
and periodic maintenance dredging has been undertaken up to the present time. Up until 
about 1960 dredging spoils were dropped just outside of the harbor; generally to the east 
of the Sand Island Sewer Outfall. In addition to shipping, the harbor is ringed with 
industry; pineapple canneries, gas and oil storage, and numerous other businesses operate 
around the harbor. Storm drainage into the harbor and nearby Keehi Lagoon carries 
runoff from Honolulus streets and suburbs into the ocean. Pollution is well known in the 
harbor. Cox and Gordon (1970) cite references describing these conditions as early as 
1920. Sewage has been pumped into the ocean offshore of Kewalo and Sand Island since 
the 1930s. These early inputs were all raw sewage, released in water not exceeding 20 m 
in depth. The actual point of release varied through time as different pipes were 
constructed and used. The multitude of perturbations that have occurred, or are still 
occurring, in shallow water (< 20 m) up until the construction of the present deep water 
outfall in 1978 serve to obscure the impacts that the present discharge of effluent may be 
having.
The waters fronting Sand Island, into which the deep ocean outfall discharges, may 
be considered in terms of gradients. There are numerous gradients due to point (storm 
drains, streams, etc.) and non-point inputs into Honolulu Harbor and environs from the 
above-mentioned activities. Because many of these inputs have been occurring for a 
considerable period of time, the species composition and functional relationships of the 
benthic and fish communities at any given location in the waters offshore of Honolulu are 
those that have evolved under the influence of these ongoing perturbations.
As noted above, if impacts are occurring in the shallow marine communities fronting 
Honolulu due to the deep ocean outfall, these are probably chronic in nature thus causing 
a slow decline in the communities so impacted. Gradients of stress or impact should 
be evident with distance from impact source(s). Thus to quantitatively define these 
impacts, one should monitor these communities through time in areas suspected of being 
impacted as well as in similar communities at varying distances away from the suspected 
source(s). This rationale has been used in developing the sampling strategy for this study.
MATERIALS AND METHODS
The quantitative sampling of macrofauna of marine communities presents a number of problems; many of 
these are related to the scale on which one wishes to quantitatively enumerate organism abundance. Marine 
communities in the waters fronting Sand Island may be spatially defined in a range on the order of a few 
hundred square centimeters (such as the community residing in a Pocillopora meandrina coral head) to 
major biotopes covering many hectares. Because considerable interest focuses on visually dominant corals, 
diurnally exposed macroinvertebrates, and fishes, a sampling program was designed that attempted to 
delineate changes that may be occurring in communities at this scale.
Three sites were selected for the monitoring of benthic and fish community response 
to possible sewage impacts. The approximate locations of these sites are given in Figure 
1. The sites were close to some stations used by Dollar (1979). Site locations and the 
rationale for their selection are given below:
Station A (Kewalo Landfill) lying east of the present deep ocean outfall in about 16 m 
of water was utilized as a control area (Fig. 1). Prevailing currents create a westerly 
movement of sewage effluent (Dollar 1979) thus the shallow Kewalo Landfill area is 
probably not directly impacted. At this location, corals occur in areas of emergent 
limestone. Local coverage over short linear distances may exceed 30 percent. This station 
is in the vicinity of Dollars (1979) Station 2.
Station B (Kalihi Channel) was located about 120 m east of the Kalihi Entrance 
channel in approximately 15 m of water. This station was about 900 m west of the of the 
bypass (old) outfall in an area heavily impacted by the old (19551977) shallow water 
discharge and was very close to Dollars (1979) Station 14. Again, there was emergent 
limestone at this station but coral coverage was low (>1%).
Station C (Reef Runway) was located in an area of complex limestone substratum, in 
water ranging from 7.5 to 12 m deep, fronting Honolulu International Airports Reef 
Runway. This station location was close to Brocks (1986) station that was monitored 
quarterly in 19771978 (AECOS, Inc. 1979) and again in 1986. It was close to Dollars 
(1979) Station 19. This site was moderately impacted by the old, shallow water sewage 
outfall (Dollar 1979).
At each site two transect lines were permanently established using metal stakes and 
plastic coated no. 14 copper wire. Transects were 20 m in length and were orientated 
perpendicular to shore. Two transects were established at each location to provide some 
replication. At each station, both transects sampled approximately the same benthic 
community. On each transect there were five permanently marked locations (0 m, 5 m, 10 
m, 15 m, and 20 m) for the taking of photographs of the benthic communities. Cover 
estimates were also made in the field with a 1 ??1 m quadrat placed at the -1 to 0 m, 4 to 
5 m, 9 to 10 m, 14 to 15 m, and 19 to 20 m marks on the transect line in the first (1990) 
survey.
Fish abundance and diversity is often related to small-scale topographical relief over 
short linear distances. A long transect may bisect a number of topographical features 
(e.g., coral mounds, sand flats, and algal beds) sample more than one community and 
thereby obscure distinctive features of individual communities. To alleviate this problem, 
a short transect (20 m in length) has proven adequate for sampling many Hawaiian 
benthic communities (see Brock 1982; Brock and Norris 1989).
Information collected at each transect location included a visual assessment of fishes 
and benthic quadrats (for cover estimates of sessile forms; e.g., algae, corals, and colonial 
invertebrates) and counts along the transect line for diurnally exposed motile macro-
invertebrates. Fish censuses were conducted over a 20 ??4 m corridor (the permanent 
transect line) and all fishes within this area to the waters surface were counted. A single 
diver equipped with SCUBA, slate and pencil entered the water, counted and noted all 
fishes in the prescribed area (method modified from Brock 1954). Besides counting the 
numbers of individuals of all fishes seen, the length of each was estimated; these length 
data were later used in the estimation of fish standing-crop by linear regression 
techniques (Ricker 1975). Species specific regression coefficients have been developed 
over the last thirty years by the author and others at the University of Hawaii, Naval 
Undersea Center (see Evans 1974) and the Hawaii State Division of Aquatic Resources 
through capturing, weighing and measuring fishes; for many species, sample sizes were 
in excess of a hundred individuals. Two weeks were allowed to elapse from the time of 
station selection and marking to the time of the first fish census to reduce the bias caused 
by wary fishes. The same individual (R. Brock) performed all fish censuses to reduce 
bias. 
Besides frightening wary fishes, other problems with the visual census technique 
include the underestimation of cryptic species such as moray eels (Family Muraenidae) 
and nocturnal species, e.g., squirrelfishes (Family Holocentridae), bigeyes or aweoweos 
(Family Priacanthidae), etc. This problem is compounded in areas of high relief and coral 
coverage that affords numerous shelter sites. Species lists and abundance estimates are 
more accurate for areas of low relief, although some fishes with cryptic habits or 
protective coloration (e.g., the nohus [Family Scorpaenidae] and the flatfishes [Family 
Bothidae]) might still be missed. Obviously the effectiveness of the visual census 
technique is reduced in turbid water and species of fishes which move quickly and/or are 
very numerous may be difficult to count. Additionally, bias related to the experience of 
the diver conducting counts should be considered in making comparisons between 
surveys. In spite of these drawbacks, the visual census technique probably provides the 
most accurate nondestructive assessment of diurnally active fishes presently available 
(Brock 1982).
A number of methods were utilized to quantitatively assess benthic communities at 
each station; these methods included the use of photographs taken at locations marked for 
repeated sampling through time (each covering 0.67 m2) and the establishment of 1 ? 1 m 
quadrats also placed at marked locations for repeated measurements. The photographs 
and quadrats were both used to estimate coverage of corals and other sessile forms. 
Photographs provided a permanent record from which to estimate coverage and were 
used in 1991. The 1???1 m quadrats were used for an in the field appraisal of coverage 
in both 1990 and 1991. Cover estimates from photographs and quadrats were all recorded 
as percent cover. Diurnally exposed motile macroinvertebrates greater than 2 cm in some 
dimension were censused in the same 4 ??20 m corridor used in the fish counts. 
If macrothalloid algae were encountered in the 1 ??1 m quadrats or photographs, they 
were quantitatively recorded as percent cover. Emphasis was placed on those species that 
were visually dominant and no attempt was made to quantitatively assess the multitude of 
microalgal species that constitute the algal turf so characteristic of many coral reef 
habitats. 
As requested by permit agencies, simple physical measurements were made at the 
three sites while in the field. Measurements were made of percent oxygen concentration 
and temperature with a YSI Model 57 oxygen meter, salinity was measured with a hand 
held refractometer, and a 12-inch secchi disk was used to determine water clarity.
Data were subjected to simple non-parametric statistical procedures provided in the 
SAS Institute statistical package (SAS Institute 1985). Non-parametric methods were used 
to avoid meeting requirements of normal distribution and homogeneity of variance in the 
data. Data analysis utilized the Wilcoxon matched-pairs signed-ranks test as outlined by 
Siegel (1956).
During the course of the fieldwork, an effort was made to note any green sea turtles (a 
threatened species) within or near the study sites.
RESULTS
Field sampling was first undertaken on 2729 December 1990. Station locations were selected and marked 
in November 1990. The permanent pins were deployed about a week later. Figure 1 presents the 
approximate locations of the three stations, each with a pair of transects. Figures 2, 3, and 4 are sketches 
showing the orientation of the permanent photographic quadrats on each transect line. The 1991 data were 
collected on 56 December 1991 from the same locations.
Malfunction of a new camera caused the loss of all photographic quadrat data for all 
stations in the previous (1990) field effort. After having photographed all quadrat sites in 
December 1990, the camera and undeveloped film were placed in a drawer and left until 
mid-1991 when the film was submitted for development. Camera malfunction was 
responsible for this loss of data and the camera was subsequently repaired. To avoid a 
recurrence of this problem, the 1991 photographic data were collected by Mr. A. 
Muranaka (City and County of Honolulu) for the 1991 survey. However, the 1990 square 
meter quadrat data provided information on benthic coverage in the first annual effort. In 
the 1991 survey both photographic and quadrat methods were used to assess the benthic 
communities.
The results are presented below by station.
Station A  Kewalo Landfill Station
This station was located 600 m offshore of the old Kewalo Landfill in water ranging from 17 to 18 m deep 
on a substratum dominated by limestone with moderate coral community development. The two transects 
were 35 m apart, out of visual range of one another (see 
Fig. 2). Visibility at this station usually ranged from 15 to 20 m.
A summary of the data collected at Transect 1 in December 1991 is presented in 
Table 1. In the quadrat survey, five coral species were encountered having a mean 
estimated coverage of 18 percent; the dominant species were Porites lobata and 
Pocillopora meandrina. One red sponge (Spirastrella coccinea) was noted in the 
quadrats. The macroinvertebrate census noted one cone shell (Conus miles), a polychaete 
(the Christmas tree worm [Spirobrachus giganteus corniculatus]), and two echinoderms 
(the sea cucumber [Holothuria atra] and the long-spined sea urchin or wana [Echinothrix 
diadema]). The results of the fish census carried out at Transect 1 are given in Appendix 
Table A. Table 2 presents the results of the photographic survey. The mean coral 
coverage in the photographic survey was estimated to be 12 percent with Porites lobata 
being the dominant coral.
In total, 31 species of fishes and 260 individuals were encountered on Transect 1. The 
most common species included:  the manybar goatfish or moano (Parupeneus 
multifasciatus), the damselfish (Chromis vanderbilti), saddleback wrasse or hinalea 
lauwili (Thalassoma duperrey), smalltail wrasse (Pseudojuloides cerasinus), and the 
brown surgeonfish or maiii (Acanthurus nigrofuscus). The standing crop of fishes on 
this transect was estimated to be 148 g/m2. The species contributing most heavily to this 
biomass were the yellowmargin moray eel or puhi-paka (Gymnothorax flavomarginatus), 
the saddleback wrasse or hinalea lauwili (Thalassoma duperrey), and the orangebar 
surgeonfish or naenae (Acanthurus olivaceus).
Transect 2 was also established offshore of the Kewalo Landfill approximately 35 m 
west of Transect 1 in water ranging from 17 to 18.2 m deep. Table 3 presents a summary 
of the biological information collected at this transect site. The quadrat survey noted one 
macroalgal species (Desmia hornemanni) and four coral species (Porites lobata, P. 
compressa, Pocillopora meandrina, and Montipora verrucosa) having an average 
coverage of 29.3 percent. The largest contributor to this coverage is Porites lobata. The 
invertebrate census counted one cone shell (Conus lividus), two polychaete species (the 
Christmas tree worm [Spirobranchus giganteus corniculatus] and the feather duster 
worm [Sabellastarte sanctijopsephi]), and one sea urchin species (Echinothrix diadema). 
The photographic quadrat survey noted two algal species (Porolithon onkodes and 
Corallina sp) as well as three coral species having a mean coverage of 24 percent. Also 
present was an unidentified sponge which was probably Spirastrella coccinea (Table 2).
The results of the fish census are presented in Appendix Table A. Twenty-six fish 
species were counted (240 individuals) on this transect. The most abundant species 
included the yellowstripe goatfish or weke (Mulloides flavolineatus), damselfish 
(Chromis vanderbilti), the saddleback wrasse or hinalea lauwili (Thalassoma duperrey), 
the smalltail wrasse (Pseudojuloides cerasinus), the brown surgeonfish or maiii 
(Acanthurus nigrofuscus), and the sleek unicornfish or kala holo (Naso hexacanthus). 
The standing crop of fishes was estimated to be 221 g/m2 and the species that contributed 
the most to this estimated weight included the yellowstripe goatfish or weke (Mulloides 
flavolineatus), the saddleback wrasse or hinalea lauwili (Thalassoma duperrey), and the 
brown surgeonfish or maiii (Acanthurus nigrofuscus).
Station B  Kalihi Entrance Channel
Two transects (numbers 3 and 4) were established on a limestone substratum about 120 m east of the Kalihi 
Entrance Channel in 13.7 to 15 m of water. This station was located about 2.2 km seaward of Mokauea 
Island situated in Keehi Lagoon and about 900 m west of the old outfall which is presently used as an 
emergency bypass. Much of the substratum in the vicinity of this station was comprised of sand and rubble. 
An area of low emergent limestone approximately 60 m wide and 110 m in length with the long axis 
oriented perpendicular to shore was present; Transect 3 was located on the deeper end of this hard 
substratum area. Transect 4 paralleled Transect 3 but was shoreward of this, and approximately 8 m to the 
west (see Fig. 3). Visibility at this station ranged from 6 to 10 m. The lack of appropriate hard substratum 
necessitated establishing the two transects at this station on an end to end fashion relatively close to one 
another (8 m apart). Because of the close proximity, the fish censuses at these stations were carried out on 
both transects prior to any other data collection.
Transect 3 had an orientation perpendicular to shore on the limestone substratum in 
water from 14.6 to 15 m in depth. Table 4 presents a summary of the biological 
observations made at Transect 3. The quadrat survey noted one sponge species 
(Microciona maunaloa), a soft coral (Anthelia edmondsoni), and three coral species 
(Porites lobata, Pocillopora meandrina, and Montipora verrucosa). The corals had an 
estimated mean coverage of 3.9 percent with Pocillopora meandrina providing the 
greatest coverage. The invertebrate census noted one rock oyster (Spondylus tenebrosus) 
and three sea urchin species (Echinostrephus aciculatum, Echinometra mathaei, and 
Echinothrix diadema). The photographic quadrat survey found an unidentified red sponge 
species (probably Microciona maunaloa which is in the area) and three coral species 
(Porites lobata, Pocillopora meandrina, and Fungia scutaria) having a mean coverage of 
4 percent.
The fish census (App. Table A) found 22 species, 138 individuals, and an estimated 
standing crop of 72 g/m2. The most abundant fishes at Transect 3 included the manybar 
goatfish or moano (Parupeneus multifasciatus), damselfish (Chromis vanderbilti), 
smalltail wrasse (Pseudojuloides cerasinus), and the brown surgeonfish or maiii 
(Acanthurus nigrofuscus). The fish species contributing heavily to the biomass on 
Transect 3 included the manybar goatfish or moano (Parupeneus multifasciatus), the 
tableboss or aawa (Bodianus bilunulatus), and the barred filefish or oili (Cantherhines 
dumerili).
Transect 4 also sampled the benthic and fish community present in the vicinity of the 
Kalihi Entrance Channel. As with the previous transect, Transect 4 sampled the limestone 
substratum at a depth ranging from 13.7 to 14 m. Table 5 presents a summary of the 
biological data collected on Transect 4. The quadrat survey noted one sponge species 
(Tedania ignis) and three coral species (Porites lobata, Pocillopora meandrina, and 
Montipora verrucosa). Coral coverage was estimated to be 3.4 percent. Porites lobata as 
well as Pocillopora meandrina were the major contributors to this coverage. The 
invertebrate census noted one small cone shell (Conus lividus) and five sea urchin species 
(the boring urchin  [Echinostrephus aciculatum], the black urchin [Tripneustes gratilla], 
the green urchin [Echinometra mathaei], and long spined urchins or wana  [Echinothrix 
diadema and E. calamaris]). In the photographic quadrat survey an unidentified red 
sponge species was seen and three corals (Porites lobata, P. compressa, and Pocillopora 
meandrina) having a mean coverage of 4 percent were also identified.
The fish census noted 68 individual fishes among 12 species (App. Table A). The 
most common fishes present on this transect included the damselfish (Chromis 
vanderbilti) and the smalltail wrasse (Pseudojuloides cerasinus). The standing crop of 
fishes on Transect 4 was estimated to be 20 g/m2. Important contributors to this biomass 
included the devil scorpionfish or nohu omakaha (Scorpaenopsis diabolus) and the lei 
triggerfish or humuhumu lei (Sufflamen bursa).
Station C  Reef Runway 
Two transects (numbers 5 and 6) were established on limestone substratum offshore of the Honolulu 
International Airport Reef Runway. This station lay between 760 and 840 m seaward of the runway in 
water ranging from 9.1 to 11.6 m in depth. The substratum in this area is a mosaic of emergent limestone 
spur and groove formations grading seaward into a series of low limestone mounds. The general orientation 
of the spur and groove formations was perpendicular to the shoreline and direction of usual wave impact. 
The spurs were from 5 to 40 m in width, 30 to 80 m in length, spaced from 10 to 100 m apart. Sand was the 
dominant substratum in the intervening areas. The maximum topographical relief formed by these spurs 
was about 3.5 m. Just seaward of this was a zone of low emergent limestone. These patches of hard 
bottom were from 5 ??10 m to several hundred square meters in size. Spacing of these limestone areas was 
between 10 to 50 m and sand was again found in the intervening areas. Corals were restricted to the areas 
of hard substratum. Visibility at this station ranged from 4 to 15 m. Usually visibility did not exceed 12 m.
Both transects were established on spurs or ridges of limestone (see Fig. 4). Transect 
5 was established on a limestone ridge in a depth from 9.1 to 11 m. Table 6 presents the 
results of the biological survey carried out at Station 5. The quadrat survey noted two soft 
corals (Anthelia edmondsoni and Palythoa tuberculosa) and five coral species (Porites 
lobata, P. compressa, Pocillopora meandrina, Pavona varians, and Montipora 
verrucosa) having a mean coverage of 2.1 percent. The invertebrate census found two sea 
urchin species, the long-spined urchin or wana (Echinothrix diadema) and the green sea 
urchin (Echinometra mathaei). The photographic quadrat survey noted the encrusting 
coralline algae (Porolithon onkodes) as being the dominant benthic form. Other species 
seen in this survey included the soft coral (Palythoa tuberculosa) and three coral species 
(Porites lobata, P. compressa, and Pocillopora meandrina) having a mean estimated 
coverage of 2 percent.
The fish census (App. Table A) counted 176 individuals amongst 28 species. The 
most common species included the manybar goatfish or moano (Parupeneus 
multifasciatus), the yellowfin goatfish or wekeula (Mulloides vanicolensis), the 
saddleback wrasse or hinalea lauwili (Thalassoma duperrey), the brown surgeonfish or 
maiii (Acanthurus nigrofuscus) and the goldring surgeonfish or kole (Ctenochaetus 
strigosus). The standing crop of fishes on Transect 5 was estimated to be 101 g/m2. The 
most abundant species were also the most important contributors to the estimated 
standing crop.
Transect 6 was established approximately 80 m seaward of Transect 5. The 
substratum at Transect 6 was similar to Transect 5 and was situated on a limestone spur 
that was about 40 m in width and 80 m in length. Water depth at this site varied between 
10.7 and 11.6 m. A summary of the biological observations made on Transect 6 are given 
in Table 7. The quadrat survey again found two soft coral species (Anthelia edmondsoni 
and Palythoa tuberculosa) as well as five coral species (Porites lobata, P. compressa, 
Pocillopora meandrina, Montipora flabellata and M. verrucosa) having a mean coverage 
of 6.7 percent. The census of macroinvertebrates noted just two species:  the banded 
shrimp (Stenopus hispidus) and the green sea urchin (Echinometra mathaei). The photo 
quadrat survey noted coralline algae (Porolithon onkodes) with a mean coverage of 19 
percent as well as two coral species (Porites compressa and P. lobata) with a mean 
coverage of 6 percent. 
The fish census found 202 individuals belonging to 29 species in the 4 ??20 m census 
area. The most abundant fishes on Transect 6 include brick soldierfish or mempachi 
(Myripristes amaenus), saddleback wrasse or hinalea lauwili (Thalassoma duperrey), the 
bullethead parrotfish or uhu (Scarus sordidus), the brown surgeonfish or maiii 
(Acanthurus nigrofuscus) and the goldring surgeonfish or kole (Ctenochaetus strigosus). 
The standing crop of fishes on this transect was estimated to be 183 g/m2. The largest 
contributors to this biomass included the brick soldierfish or mempachi (Myripristes 
amaenus), the bluespot grouper or roi (Cephalopholis argus), the yellowfin goatfish or 
wekeula (Mulloides vanicolensis), the bullethead parrotfish or uhu (Scarus sordidus), 
and the goldring surgeonfish or kole (Ctenochaetus strigosus).
Usually present at Transect 6 were from one to three green sea turtles (Chelonia 
mydas). During the present survey one individual was seen resting on the bottom in the 
transect area; this individual had an estimated straight line carapace length of 60 cm. In 
the 1990 survey three green turtles were seen; one of these was in the same location 
(carapace length 70 cm) as the turtle encountered in the 1991 survey. Green turtles are 
regularly encountered in the vicinity of Transect 6. None of these turtles appeared to have 
tags or obvious tumors present.
Physical measurements were made on the morning of 6 December 1991. These data 
are presented in Table 8. Little variation was noted in temperature (24.9 to 25.1C), 
percent oxygen saturation (101 to 102%) or salinity (all 34) despite the fact that 
measurements for oxygen and temperature were made both at the surface and about 1 m 
above the bottom. In all cases secchi disk measurements did not yield an extinction value; 
water clarity was such that the disk on the bottom was still plainly visible from the 
surface. Probably a better method of determining water clarity would be to collect water 
samples and measure turbidity with a nephalometer in the laboratory.
The biological data for both 1990 and 1991 were summarized as means for each 
transect in Table 9. The 1990 data, other than for fish, were from Brock (1991). The 1990 
fish census data is presented in Appendix Table B. Inspection of some parameters (e.g., 
coral coverage, number of coral species, and number of invertebrate species) suggest 
little change between the two sample periods. Other parameters (number of fish species, 
number of fish individuals, and fish biomass) suggest that some change has occurred. 
However, statistical comparison of the parameters between the two annual surveys shows 
that none of the changes are statistically significant (Wilcoxon matched-pairs signed-
ranks test for coral coverage P > 0.86, N.S.; number of coral species P > 0.62, N.S.; 
number of invertebrate species P > 0.69, N.S.; number of fish species P > 0.29, N.S.; 
number of individual fish P > 0.13, N.S.; and fish biomass P > 0.38, N.S.).
The biological parameters measured in the 1990 and 1991 surveys (i.e., number of 
coral species, percent cover, number of macroinvertebrate species, number of fish 
species, number of individual fish, and biomass of fishes), point to the fact that the 
Kewalo Landfill site has the most diverse communities, followed by the Reef Runway. 
The least diverse community appears to be at the Kalihi Entrance Channel site; this 
hierarchy did not change between the two surveys. The low biological diversity at the 
Kalihi Entrance Channel site is not surprising in view of the fact that this station was 
heavily impacted by the old shallow water sewage outfall until 1978. 
From a commercial fisheries standpoint, a number of important species were 
encountered at both the Kewalo Landfill and Reef Runway sites including goatfishes 
(weke [Mulloides flavolineatus] and wekeula [M. vanicolensis]), emperor or mu 
(Monotaxis grandoculis), and the squirrelfish or menpachi (Myripristes amaenus).
DISCUSSION
Since their delineation in December 1990, the six transects were visited on a number of occasions to insure 
that the permanent markers remained in place, etc. During these visits reconnaissance surveys were carried 
out in the areas surrounding the selected stations. At a minimum, these quantitative surveys covered about 
4 hectares around each of the three sites. These qualitative observations suggest that the marine 
communities sampled at the three stations are representative of those found in the surrounding areas.
The working hypothesis is that all three study sites, being situated in relatively 
shallow water, are outside of the zone of influence of the present deep water outfall. 
However, if impacts from the present deep ocean outfall are occurring in the shallow 
water coral reef areas shoreward of the outfall, our monitoring should be able to 
quantitatively discern these impacts. Because of bottom time constraints, potential 
dangers with deep diving, and the fact that coral community development is usually 
greatest in water less than 30 m deep, the placement of biological monitoring stations was 
restricted to waters 20 m or less in depth in this study. Monitoring the shallow-water 
stations provided additional information regarding the recovery of these communities 
from the damage done by the release of raw sewage from the old shallow-water outfall, a 
practice terminated in 19771978. Dollar (1979) showed that the Kewalo Landfill station 
was not directly impacted by the old outfall, but the Kalihi Entrance Channel station was 
acutely perturbed and the station offshore of the Reef Runway experienced an 
intermediate level of disturbance. The result of these impacts was still evident in the 
average coral cover estimates made at these stations:  the mean coverage offshore of the 
Kalihi Entrance Channel was only 4 percent, at the Reef Runway station it was 5 percent, 
and offshore of the Kewalo Landfill it was 24 percent.
The shallow marine ecosystem fronting Sand Island and Honolulu has been subject to 
considerable disturbance from human activity over the last 100 years. Among the 
disturbing factors was the disposal of raw sewage effluent in shallow water from the 
1930s up until 19771978 when the deep ocean outfall became operational. In the period 
from 1955 to 1977 the shallow outfall released 3 m3/sec (62 mgd). Dollar (1979) noted 
two distinct zones of impact to marine communities:  the area of acute impact was an 
ellipse 500 m to the east and 1,000 m to the west of the outfall. Outside of this area the 
impacts were evident in a decreasing gradient with distance from the outfall. The 
maximal extent of impact attributed to this sewage input was 1.9 km to the east and 5.8 
km to the west of the outfall. The elliptical shape of the zone of influence was attributed 
to the predominant westerly direction of current flow.
The Kewalo Landfill station was 4.75 km east and inshore of the terminus of the deep 
ocean outfall, the Kalihi Entrance Channel station was about 2.1 km east and inshore of 
the terminus and the Reef Runway station was about 3.25 km inshore and west of the 
deep ocean outfall terminus (Fig. 1). Presumably the present outfall releases the sewage 
below the thermocline and little interaction occurs with the inshore biota. If, however, the 
effluent was carried into inshore waters, impacts to shallow marine communities would 
occur in those communities situated primarily to the west of the outfall based on Dollars 
(1979) findings.
The Kewalo Landfill station served as a control site in this study; despite the fact 
that coral coverage and fish community development was greater at this location, the 
Kewalo Landfill station has been subject to sewage impacts in the past. The two transects 
(T-1 and T-2) at the Kewalo Landfill site were situated close to an old, non-operable 
sewage discharge pipe. Operations utilizing this pipe ceased sometime prior to 1955. The 
pipe was probably used sometime in the 1940s (Mr. A. Muranaka, Oceanographic 
Section, Division of Wastewater Management, City and County of Honolulu). The 
development of Kewalo Basin and the entrance channel 200 m to the east in the mid-
1930s would have created considerable turbidity that probably impacted this site. From 
the historical perspective, human impacts have probably occurred in all marine 
communities situated in shallow waters fronting Honolulu over the last 100 years. The 
Kewalo Landfill site was selected as the control site for this study because of the 
relatively diverse coral and fish communities present and because it was well to the east 
of the present deep ocean outfall (presumably out of the zone of influence).
The data over the two observation periods (December 1990 and December 1991) 
show that no statistically significant change has occurred in the biological parameters 
measured in this study. Inspection of Table 9 (the summary table) suggests that some 
change has occurred in the numbers of fishes identified and counted and the standing 
crop or biomass of fishes at several of the transect sites between the two surveys. In 
particular, the number of individual fish and biomass decreased between the two surveys 
at Transects 1 and 2 (the Kewalo Landfill station). Relative to many other locations in the 
Hawaiian Islands, the fish community was well developed at the Kewalo Landfill station. 
The high standing crop estimates in 1990 were much greater than those found on most 
coral reefs; the maximum fish standing crop encountered on natural coral reefs is about 
200 g/m2 (Goldman and Talbot 1975; Brock et al. 1979). There are two explanations for 
the high biomass of fishes at the Kewalo Landfill site:  (1) the shelter created by the old 
sewer pipe locally enhanced the fish community, and (2) chance encounters with roving 
predators or planktivorous schooling species during censuses.
Space and cover are important agents governing the distribution of coral reef fishes 
(Risk 1972; Sale 1977; Gladfelter and Gladfelter 1978; Brock et al. 1979; Ogden and 
Ebersole 1981; Anderson et al. 1981; Shulman et al. 1983; Shulman 1984; Eckert 1985; 
Walsh 1985; and Alevizon et al. 1985). Similarly, the standing crop of fishes on a reef is 
correlated with the degree of vertical relief of the substratum. Thus Brock (1954) using 
visual techniques on Hawaiian reefs estimated the standing crop of fishes to range from 4 
g/m2 on sand flats to a maximum of 186 g/m2 in an area of considerable vertical relief. If 
structural complexity or topographical relief is important to coral reef fish communities, 
then the addition of materials to increase this relief in otherwise barren areas may serve to 
locally enhance the biomass of fish. The additional topographical relief is usually in the 
form of artificial reefs but any underwater construction activity (such as the deployment 
of a sewer line) will have a similar effect. The old sewer discharge pipe was set above the 
seafloor creating considerable local topographical relief (about 2 m high) in an area 
where the maximum natural vertical relief does not exceed 25 cm. The shelter and high 
topographical relief must foster greater development of the fish community (see Brock 
and Norris 1989).
Chance encounters with large roving predators (such as uku [Aprion virescens], mu 
[Monotaxis grandoculis], kahala [Seriola dumerili], papio [Caranx melampygus or C. 
orthrogrammus]) or schools of planktivorous fishes (opelu [Decapterus macarellus], kala 
holo [Naso hexacanthus], kala lolo [N. brevirostris], lauwiliwili [Chaetodon milaris], and 
mamo [Abudefduf abdominalis]) may greatly increase the counts and biomass of a 
particular transect. The presence of the sewer pipe serves to focus numerous predators 
and planktivorous fishes in the vicinity of the two transects at the Kewalo Landfill site 
and encounters with these fishes during a census will result in high biomass estimates. 
Chance encounters with a small school of mu or emperor (Monotaxis grandoculis) at 
Station 6 (Reef Runway) accounted for 51 percent of the biomass of that station in 1990. 
On Transect 2 (Kewalo Landfill) the two planktivorous surgeonfishes (kala holo and kala 
lolo [Naso hexacanthus and N. brevirostris]) accounted for 40 percent of the biomass and 
the two roving predators the kahala (Seriola dumerili) as well as the papio (Caranx 
orthogrammus) contributed 21 percent to the biomass estimate for that transect in 1990. 
In 1991 these planktivorous surgeonfishes and some predators were present around 
Transects 1 and 2 at the Kewalo Landfill site but did not enter the actual census area 
while the counts were proceeding and thus do not appear in the data.
Making biological measurements underwater can often be a time-consuming process; 
use of the photographic technique lessens bottom time in measuring coral and other 
benthic species coverage. However, inspection of the results of the coral coverage data 
from visual appraisal of quadrats in the field (Tables 1, 3, 4, 5, 6, and 7) relative to the 
data from the photographic method (Table 2) points out several things. First, mean coral 
coverage estimates are in reasonable agreement by either method. Regressing the 1991 
visual versus photographic coverage data results in a statistically significant relationship 
(r2 = 0.98), given by the equation Y = 1.29X  0.67 where X is the coral coverage 
measured by photo techniques on a transect and Y is the expected coverage obtained by 
visual techniques on that same transect. A drawback to the photo quadrat technique is 
that it does not discern small coral colonies or other small colonial benthic species such 
as the soft coral Anthelia edmondson. These are easily seen in the field using the visual 
assessment method. Both methods work but method selection should be done keeping the 
objectives of the study in mind.
The six transects selected for this study showed a considerable range in community 
development probably related to past (historical) impacts. Separating the impact of 
advanced primary treated effluent released at depth, from a multitude of other ongoing 
and historical impacts that have occurred in and to the shallow marine communities 
fronting Sand Island is difficult at best. However, the siting of these permanent stations to 
capitalize on presumed gradient(s) of impact created by the variety of land derived 
sources as well as the repeated sampling of these permanent stations should allow 
delineation of any changes attributable to the Sand Island deep ocean outfall. The 
sampling of these stations one year apart shows that there has been little change to the 
communities over that period of time. This finding suggests that over this one year 
period, there has not been a quantitatively definable impact to shallow water benthic and 
fish communities due to the operation of the Sand Island deep ocean outfall.
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