Trophic Relationships of Goatfishes (Family Mullidae) in the Northwestern Bawaiian Islands
TROPHIC RELATIONSHIPS OF GOATFISHES (FAMILY MULLIDAE) IN THE NORTHWESTERN BAWAIIAN ISLANDS
!THESIS SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAII IN PARTIAL FULFULLMENT OF THE REQU.IREl'!EN'fS FOR THE DEGREE O.P MASTER OF SCIENCE IN ZOOLOGY MAY 1982
by
Carol T. Sorde.n
Thesis committee: JulieB.. Brock, Chairman Ernst S. Reese John S. Stimson
- i - We certify that we have read this thesis and that in our opinion it is satisfactory in scope and quality as a thesis for the degree of Master of Science in Zoology.
Thesis committee
Chairman
- ii - lCKBOWLBDGEHEli"lS
'fhis thesis would not have been possible without ·the help of Stan Jazwinski and Alan Tomita wbo collected the samples a·t Midway, and 'fom Mirenda who identif.ied tbemolluscs. Many thanks to all my 'ft:iends in Hawaii and Alaska for all theit:: support, especially Stan Blum and Regie Kawamoto. "I am grateful to the members o.f my committee for encouragement and guidance, particularly my chairman, Dr. J. H. Brock, who gave ccntinued mot::al as well as academic suppot::t. Thanks also to Dr. J • .B. Randall fot: help with the taxonomy of l'Iulloide§, and Dr .E. A. Kay for help wi·th mollusc problems. This thesis is the result of research (Project No. NI/R-tl) supported in part by the university of Hawaii Sea
Grant College Program under Institutional Grant Numbe.rs N1 79 11-D-00085 and N1 811A-D-00070, NOAA Office of Sea Grant, Department of Commerce. Further information on tbe original data may be obtai ned from the Hawaii Cooperative Fishery Research Unit, U.niversity of Hawaii. Last, but not least, I would like to thank my children, Renee, Geoff and Rachelle, who have been through a lot to give their mother an education.
- iii - CONTENTS
ACKNOWLEDGEMENTS ...... ,. ... . ,...... iii
LIST OF TABLES ...... ,...... '. . .,. v LIST OF FIGURES • ...... "...... vi
I. .INTBO.DlJCTION • • ...... 1
II. MATEllIALS AND !!ETHODS .. .. '4 • • ,...... 7
SUBSTRATUM SAMPLING PROCEDDIE • ...... 13 SAMPLE SITES ...... • • 14 III. RESULTS ...... 18 Parupensus porpbyreus ...... • ...... • 18 Mulloides vanicolensis ...... • .. .. 19 Mulloides flavolineatus ...... • 21 Parupeneus multifasciatus ...... • .. 26 Parupeneus pleurostigma ...... • .. 28 Overlap and Preference ...... 31 Benthic samples ...... 40 crustacea _ ...... • .. 41 Other animal groups • ...... 42 Polychaetes ...... 42 Diversity and Similarity analysis .. • 45
IV. DISCUSSION • • .. • ...... • .. • .. • ...... 51
V. CONCLUSIONS ...... • ...... • .. • .. • .. • ...... • .. .. 61
A~dix .£a.9~
A. SPECIES IN BENTHIC SAMPLES • ...... • • .. • ...... 65
BIBLIOGRAPHY .. • .. .. • ...... • .. .. • ...... 81
vii LIST OF TABLES
1. lumbers of each species of goatfisb collected ...... 10
2. Ranks of food items of Parupeneus porpbyreus a ...... 18
3. Banks 0.£ food items of nulloides vanicolensis " .. .. 20 4 .. Ranks of food items of Mulloides f la '10 Ii neat us · 22 5. Polychaete species in the diet of Mulloides flavolineatus ...... " • ...... • ...... · . ,. .. 24 6.. Ranks of food items of Parupeneus multifasciatus .... 21 7. Banks of food items of Parupeneus pleurostigma • .. .. 30 8. Dietary overlap between goatfisb species at Midway .. 38 9. Characteristics of sand samples at Midway · '. . . • 41 10. Molluscs in benthic samples Station 1 · .. .. · ...... 66 11. Molluscs in bentbic samples Station 10 ...... • .. 68 12. Molluscs in bentbic samples station 14 .. • ...... 69
13. Molluscs in bentbic samples Station 16 .. " .. • .. .. • 71 14. Molluscs in benthic samples station 21 .. .. 73 · .. .. " • 15. Animals in benthic samples Station 1 ...... • .. .. • .. 75 16. Animals in bentbic samples Station 10. • .. .. " " .. .. 77 17. Animals in benthic samples Station 14 .. • • ...... • 78 ··18.;- .- An-imalsinbentbic ·samples Station 16 •• · .. . • • 19. Animals in benthic samples Sta tion 21 · . ., .. . . • 80
- viii - LIST OF FIGURES
1. location of sample sites at Midway Islands .. . .
2. Polychaete species in sand and guts Station 14 .. ;0 ;0 33 3. Polychaete species in sand and guts station 21 ...... 36
4. Similarity analysis with qualit ati va data .. ,. .. .. • • 46
5 .. Similarity analysis with quanti tati va data " .. • • .. 49
- ix - I IITBODUCTIOII
Sa:nd and rubble substrata associated with coral reefs may comprise a large percentage of the surface area of the reef
(Thomassin 1918). The infauna of these areas are important food of reef dwellin 1914) and in the trapp.ing and disturbance of sediments (Bailey-Brock 1(19). Analys.is of coral ree.f soft sediment communities has concent.rated on certaintaltonomic groups e.g- polychaetes (Bailey-Brock 1916), molluscs (Salvat 1961, 1910) and crustaceans (Thomassin 1914) •. Studies in the Indo-Pacific region describing community composition of coral reef sediments include Banner and Randall (1952), Salvat and Renaud-PIornant (1969), Gibbs (1978) and Edmondson (1946). The sand and coral infaunal communities of the atolls of the Northwestern Hawaiian Islands (NiHI) are not well known. Preliminary and incomplete data were obtained ·for the sessile benthos from a number of islands in the NiHI chain (Boucher pers. comm.), and the coral cryptofauna of French Frigate Shoals (Sorden 1980). Apart from some studies of micro-molluscs (Kay pers. comm.) the soft sediment - 1 - 2 communi·ty composition bas not. .been described from a.ny of the liRT. The inve.rtebrat.e infauna of soft sediment substrata provide a food resource for many species of coral reef fishes. Among these are a number of species of goatfishes (family Plullidae),whicb possess a pair of sensory barbels to aid in the location of prey amongst the sand. Goatfish barbels, located at the tip of the lower jaw, co.ntain abundant t.astebuds and are enervated by a la.rge branch of the facial nerve (Holland 1976, Suyebiro 1942) •... The barbels are used to detect potential prey in the sand, which is then dis·turbed by 'blowing' (Holland pers. comm. ), or digging with the pectoral fins (pe.rs. obs.). Holland (1976) found that the barbels were essential for the location of food by !~rlU!ene!1SlPorR.h.!.f~!!§. Taste buds a.re also abundant in sensory papillae in the buccal cavity. The mouth is protrusible, with small weak teeth; goatfish lack the crushing dentition found in some other fish families, e .. g_ .. Labridae (A1=Hussaini 1946,1947). Goatfish are often accompanied wbenfeeding by othe.r fish species that prey on the dist.urbed infauna (Robson 1968,1974). The family Plullidae is dist.ributed worldwide in t.ropical waters. All species are marine and carnivorous (Fowler 1933). Ele ven species belonging t.o t.hree genera are represented in the Hawaiian Islands (Gosline and Brock 1960, 3 Randall 1980). In the high Hawaiian Islands there is a commercial and subsistence fishery for goatfish, all species of which are highly esteemed as food. The early Hawaiians used species of Mulloides1 and EarJH!!neus both as food and as offerings to the gods (Titcomb 1912)., Goatfish are also a prey item for pisci vorous fish such as ulna (Ca.rangidae), and are an important diet item of seabirds, at least in the NIlHI (Harrison and Hida 1980). The diet of mnllid species has been studied int.he west Indies (Randall 1961), Puerto Rico (Bauer 1981), India (Thomas 1969) , Madagasca.r (Harmelin-Viv.ien 1919), and Japan (Suyehiro 1942). Pacific studies include Hiatt and strasburg (1960) at Enewetak,Marshall Islands, and Hobson (1914) off Kona, Hawaii. Mahi (1969) did a comprehensive study of the diet of RAIU!!1!~'§l!2!W!.I!!.§both juveniles a.nd adults. Five species of goatfish were included in the large trophic study of fishes of the Kana coast, Hawaii (Hobson 1974). Somewhat incomplete data are available on the diet of lyl!.oides!lSlvol!pefl\u§" from the NYHI (Okamoto and Kawamoto 1980) and ji. " flavolin!.~.1B§, ji.!anicol~n§i§, from Oahu (Kluegel 1921)., There are no data on the diet of fSlrUjeneJ1..e eleures!ig.!A from any location, er of t Dr. Philip Heemstra has found tha·tthere was no need for the establishment of the genus Mulloidicht~I~and that Mulloides·· is the valid genus name (through J •.' E. Randall pars.cemm.) 4 ..f. !U!l ti fasciatlls from NiHI. The mullids include both diu.rnal e.9-. Parup!neu.§ .. !ultil.a~c!atus,. and nocturnal or crepuscular feeders e.g. ,aull.9iges v ani~ol§nsi§, .fa~UBeJ1e!,}s a9.'l!h!!i~Um (Ho bson 1974,. Kahi 1969, Rarmelin-Vivien 1979) •.. The major food items consumed by most species are crabs, shrimps,. amphipods and other small crustaceans,. polychaetes, and bivalve and gastropods molluscs. Species which eat fish include fiu:uj!eneJ!§ luteys (Barmelin-Vivien 1(79) and I. £b'!;Is§,ydr9~ (Hobson 197q). However, diet composition appears to vary with locale and size o.f fish. Within one spec.ies the important p.rey i temsmay differ between islands, or between sites on the same island. In the Marshall Islands fish were the dominant prey of 1. liavolineat.!1:3(Hiatt and Strasburg 1960)where.as at Kona, Hawaii this species ate mostly bivalve molluscs, polychaetes and amphipods {Hobson 19714). l!tenoEYssp. vas one of the major prey of .f. porphl:~'§ at Kaneohe, Oahu but was almost absent from the diet of fish caught at iaikiki, Oahu (Plahi 1(69). Small individuals of .f- J?Q!l!blre.!.§have a dif.ferent diet from intermediate and large fish afthe same species (Plahi 1969). This may be a reflection of localized differences in food or may indicate thatgoatfish are non-specialized feeders eating ·the most common prey available at each location. 5 Feeding selectivity is a measure of the differences between tbe species composition of the diet and the environment (Jacobs 1974, Gabriel 1978, Cock 1978). Assuming that all prey are equally available to afisb then positive selection occurs wbenthe relative abundance of a prey item is greater in the diet than its relative abundance in the e!',vironment. No selection occurs when prey items are eaten in proportion to their relative abundance (lvlev 1961, Gabriel 1978).. This is tbe feeding type described by Birkeland and Neudecker (1981) as a 'passive generalist'. selectivity also depends on other factors such as the distribution and predator defenses of the prey, predator hunger, size of predator and prey, etc (Ivlev 1961, Chesson 1978, Jacobs 1974). While the diet of a number of mullid species bas been determined for several locations the degree of feeding selectivity, if any, bas not been studied. Hobson. (1974) made numerous observations of feeding behavior as well as analyzing gut contents, but be did not determine the composition of the benthic community. Thomas (1969) . correlated diet with fish si2e and seasonality in four species of goatfish in the Indian Ocean. Gut contents and digestive and feeding morphology were used in trophic studies o.f reef fish, including goatfish, in the Marshall Islands (Hiatt and strasburg 1960) and the Red Sea (Al=Hussaini 1947,1949). 6 This study attempts to determine the species composition of the sand infaunal community from representative habitats at Midway Islands, NiHI, and the extent of goatfish predation on sand/rubble infauna. By comparing potential prey (from sand samples) with the actual prey (from gut contents) feeding selectivity, if any, is determined. Data on predation en goatfish from published studies assist in establishing the trophic relationships between piscivores, goatfish, and sand dwelling invertebrates. II 8ATEBIALS AND ftETBODS Samples were obtained from the Sidway Islands of both sand and goatfish from five locations in the lagoon, (Figure 1), chosen as represen tat! ve of the diversity of habitat types in the area. Goatfish samples were collected at the same time and location as the sand samples. In most caseS the goatfish ware observed feeding in the areas from which the sand samples werataken. All collections were made during the day between 1000 and 1600 hours. The station numbers for the collection sites at Midway Islands are those established for a larger study on the trophic structure of reef fish communities in the NiHI, of which this thesis is a part. For this reason the stations are not numbered from one to five. A total of 101 individuals belonging to five species were collected from five stations (Table 1). The species were ..ru!llc~ !lav91!neat.Y~ (31 individuals), Lt- .!S!ni£Qlen~.i2 (22 individuals), ~u.een~u2 nm!asciatJ!,2 (20 indivi duals), .f. 1!l~urostig..!l!A (14 individuals) and f. lH2IPh.I~~us (14 individuals). The Hawaiian names for these species are weke 'ula, weke 'a'a, moana, malu and kumu respectively. only at station 1 were all five species collected. - 7 - 8 Figure 1: Location of sample sites at Midway Islands 9 10 TABLE 1 Numbers of each species of goatfish collected Midway Islands August 1980 station Species 1 10 14 16 21 Total ji .. vanicolensis 3 6 8 4 1 22 /1 .. II~voJ.!neati~ 5 10 4 12 31 11· nIt! f~cia.tu.2 4 1 7 Ii 4 20 g. .E}~U1:: o~1i9!ls 2 6 3 3 14 .f. . J2.QrEhI~~J!e 6 8 14 Total number of individuals 20 15 31 15 20 101 21, ~. l?J.S:P.Iostigp!~ and !!!!11:oiQ,es flavolin~atus were not collected at Station 10.. Large schools of !!. 1lA!9.~in~sj;J!§ and !!. v*lli~olelli§ were seen in the lagoon, though ll .. yanic.2l:§t.!!2is was not as common, being observed mostly near caves. .f.gru!!gne'y,,§ EQr2l!I~were usually seen as solitary individuals near caves or on the ocean side of the abundant, with at least one individual observed on every dive.. This species was often associated with ~ .. !!y!:!:i- fascis~ of similar size swimming and feeding together. Parup~.Y2 .!!J!.!t;;ifascia.1l!§ was common, usually seen in groups of two to three and oft·enwitb one g .. J2,ls1!!.2§!.i.9.!.S as fart 11 oftha g.IOUp. Fish species observed feeding with goatfish, especially .f. Jlyltifa§£i.5!i!!2 and.f. plett~§!!9J!AI included labrids and chaetodon tids(Nor.ris pers. comm.). All fish were speared with the Hawaiian pole spear. The gut cavity was injected with 1001 formalin (371 formal dehyde) at the collection site, as soon as possible after spearing. On return to sborethe fish were prese.rved in 101 formalin for transportation to Honolulu. In the laboratory fish were weighed, standard, fork, and total lengths were measured, and the fisb were gutted. Sex and reproductive condi tion, i.e. immature, mature or gravid were dete.rmined from examination of the gonads. Females were classified as gravid when the gonads contained large sepa.rate eggs, and the gonads were large relativetotne size of the body cavity. Mature females were those where the gonads were relatively small and the eggs were recognizable but not separate. The fish guts and gonads were preserved in 70i ethanol for further work. After cut.ting open a fish gut all contents were removed, keeping stomach and intestinal contents separate. Identifiable organisms were counted and volume displacement taken of each prey category, and of unidentified food material. Counts of partially digested and broken animals were determined by dividing the number of crustacean eyes and bivalve valves by two. A set of jaws or a head of a 12 polychaete were counted as one individual. Identification of prey was made to the lowest possible taxon, genus or species in many cases.. As the degr·ee of digestion determined the level of identification the same species may sp., unidentified portunid, or even as unidentified crust acean. The Index of Relati va Importance, IRI (Pinkas ~ al 1965) was calculated for each prey category. The IHI : F (N+Y) , where .F is the fregue ncy of occurrence in per:cent, N the percent of total individuals and Y the percent of total volume. The index allows one to rank diet items, and because it includes both numerical abundance and volume it should not be biased by large numbers of very small organisms, or by the effect of differential digest.ionon volumetric measurements. Dietary overlap between species was calculated from the proportional Similarity Index PSI = 1 - .5(p - q ) where p represents the proportion of the ith category in the diet of one species and q the proportion of the ith prey in the second species. This index has been used in diet studies as a measure of overlap and of niche breadth (Schoener 1968,1970; Colwell and Futuyma 1971). The same overlap was used to assess feeding preferences by calculating the overlap between the prey eaten and the available prey in the 13 benthos. When used as a measure of preference the values of PSI range from 1. 0, which indicates a broad feeding niche, to the min (q ) wben the fish is obt,ainingmost of its food from the rarest prey in the benthos (Feinsinger ~A!" 1981). Although data were collected separately for stomach and intestinal contents the results are combined as no differ ence was found between them. Fo.!' calculation of the Index of Relative Importance (IB1) the prey we.re grouped into larger categories, family or order, even when identified to genus or species. Overlap and diversity indices were calculated at the species level. Th.reereplicate sand samples were taken at each location, using corers made from three pound coffee cans, so that a two li,tre sample was taken with each core. The sand was fixed with 10~ formalin and seawater and rosa bengal was added as a vital stain. In the laboratory a 25 ml subsample was taken for micromolluscs. All macroscopic animals were removed and the remaining sand was dissolved in nitric acid a-ndformalin {Brock--andBrock 1977ltoremove the carbonate fraction. The residue was then sorted under a Bausch and Lomb dissecting microscope and all animals were removed # identified, and counted. The micromolluscs from tbe 25 ml suhsample were identified and counted separately. 14 species diversity was calculated using the Shannon-Weaver information index Ht (Pielou 1966). community similarity was calculated using the community analysis program on the HP 2000 computer (Mueller- Dombois ~Z .a! 1981). In this program a dendrograph is constructed from a similarity matrix based on the Sorensen index of similarity, IS -= 2W/(A + B) x 100 where A is the sum of quantitative values of all species in sample A, E is the similar sum for sample H, and W is the smaller of two quantitative values of species common to A and B. Midway Islands are located at 280 23'N latitude and 1770 23 f t\' longitude near the extreme western end of the NiHI. The atoll consists of a circular coral reef, 24 tm in circumference, which is raised in places up to 1. Sm above sea level. There are two islands in the lagoon, Sand Island (3.84 sq. km.) and Eastern Island (2.4 sq. km.) (Dollar 1(78) • Midway Islands are operated by the O.S. Navy and cOlisiderable alterations have be en- llradeto certain areas of the atoll. A channel and deep water harbor have heen dredged to the south and east of Sand Island (Dollar 1978). The natural channel through Seward Roads into Welles Harbor (see Figure 1) was 'deepened and improved' by the O.S. Navy 15 in 1870 but the work was never finished (Thorp 1960). Because of these alterations and the effect of a lODg-term relatively large population of military personnel at Midway from 1939 to 1978 the atoll does not represent as natural an environment as some other islands in the NiHI chain.. In 1978 Midway Naval Station was changed to an unaccompanied duty station with a corresponding reduction in population. Little fishing is done in the lagoon because of the possibility of ciguatera poisoning. Some recreational boating and diving are the main activities outside of the two islands. Therefor"e, apart from Station 1, tbe sample sites are relatively undisturbed. The locat.ions of the five sample sites are indicated in Figure 1. Station 1 is unde.rneath t.be cargo pier in the harbor on Sand Island, at a depth of 10m. This is an area that has been dredged for harbor construction, and represents a distu.rbed environment. The bottom was very silty and visibility was poor.. Many species of fish, including mullids, were abundant and were regularly seen feeding at Station 1. The sediment samples contained much extraneous material such as wood or concrete, with the sediment itself being very fine and silty. Specific grain size analYSis was not performed on the sediment samples; estimates of particle size are subjective and based on broad categories such as coarse sand, fine sand, etc. 16 stations 10 amd 14 are located together, one inside and one outside the reef. The sand samples at Station 10 were taken iothe bottom cfthe surge channel, at a depth of 6.6m immediately outside the fNotch' (a gap in tbe reef allowing access to the outside).. The three species of goatiish collected there (Table 1) were the only ones observed frequenting tbe area, although they were not observed feeding. At Station 14 the sand was sampled in 2-4m of wa terjust inside the reef wber:e an area of !1onliJ2.2ll s p. and .i9£illopors sp .. end and .f2!i.!~§ comeres§S becomes dominant. There are numerous patches of fine sand where blliide§ !l.a!21in~s.!'y§, fA.t!4R~nil!§ .2li!!I:.Q.§yg,!s and .f. 1l,I,pltilliciat.lH1 were seen feeding. Tha sediment in the samples vas medium sized sand. Station 16 is located in an area of patch l>eefsnearthe canter of the lagoon. The sand was sampled .beside a coral pinnacle at a depth of 6.6m. The pinnacle is composed of mostly livef2!'~ £Q'!!..f1£~'§§A rising to within 2.6m of the surface. All five species of goatfish were seen on and around this and neighbouring pinnacles. The sediment at this station consisted of very fine white sand. station 21 is similar: to Station 14, occupying the same position relative to theree!.. There is more 11Qntlio!:i! Spa present than at Station 14 and the water was 1-2m deep_ Most of the sand was in a layer 1-2cm deep overlying 17 consolidated limestone, wi th very few deep sand patches. The sand was similar in grain size to Station 14. III RESULTS (Table 2). Six fish ate xanthid crabs, two ate stomatopods, and one a E..Q.rtu!!-.1H! Spa One stomatopod was identified as J!seud.Q~gui!.la£iliata.Fou.rspecies of xan thid crabs were eaten .. TABLE 2 Ranks of food items of P.arupeneus porphyreus All stations combined. Number of fish with gut contents = 8 Prey %N* )tv * %F* IRI Xanthidae 63 .. 0 88.2 75.0 11340.0 Stomatopoda 7.4 4.5 25.0 291.5 Portunus s·p_ ).7 o. 1 12.5 l.17.5 -unidentified--- crustacean fragments 22.. 2 4.5 12.5 333.8 food • 2 .. 8 12.5 15.3 *Percent oftotalnumhers, volume, and frequency of occurrence of pr:ey in guts - 18 - 19 All fourteen specimens collected had empt.y stomachs. Eight had identifiable intes·tinal contents, three collected at 1030, two at 1400 and three at 1500 hours. Because of the small sample size data from all stations are combined_ This species had the largest individuals of any of the five goatfish species collected at Midway, with a mean standard length of 260.07mm, and a range of 151 - 355mm. Six of the specimens were female, only one of which was mature. Four of the eight males were mature. xanthid crabs were the dominant prey followed by gastropod molluscs and polychaetes (Table 3). Species of crabs eaten included the portunid Th~la,!ti:!f& sp. and the x anthid ?,!.jH~todi.!!f! Us!ll!!.!- Thirt y-fi ve of the 38 gastropods in the gut cO.ntents were one species, Cyst.j.cus· huns (family Marginellidae). £y!i£.!!§ U..!S!·' is a carnivore feeding on sponges and ascidians (Kay pers .. ,,' comm.); however no sponge spicules or asci dian remains were found in the ,11. l'.£\nicolensis" guts. Three species of polychaetes were -found ,-NotiIr~a ", holobranchi:ata,-Tvsidice 'sp. and an - .... _- -- ~...... -- unidentified dorvilleid •. Al though !J»lloi£1~§ !ani£.glen!ii.~ was collected at all five st.ations recognizable gut contents were found only in fish from stations 10 and 14. Data from thes-e two stations were 20 TABLE 3 Ranks of food i tams of Mul10ides vanicolensis All stations combined. Number of fish with gut contents = 10 Prey ~N* IV* iF* IRI Xanthidae 17.9 26.2 50.0 2205 .. 0 Gastropoda 40.0 3.0 30.0 1290.0 Polycbaeta 7.1+ 2.3 40.0 388 .. 0 Ostracoda 4.2 0.7 20.0 98.0 Portunidae 2. 1 0.6 20.0 54.0 Fish 1.0 3 .. 3 10.0 43.0 Bivalvia 2.1 0.2 10.0 23.0 Crab megalops 1.0 0.1 10.0 11 .. 0 Caridean shrimp t.O o. 1 10.0 11.0 unidentified food 51.4 90 .. 0 4112 .. 0 unidenti.fied c:rnstacea ns 2J.2 12.0 80.0 3168 .. 0 *PercBnt of total numbers, volume, and frequency of occurren.ce of prey in guts combined because of the small sample size and because there appears to be no difference in diet between stations. All 22 specimens of 11. y'~\!i£,g!~!ls!.i.§· had empty stomachs with 54.51 baving totally empty guts. The sex ratio was 11 males to 9 females witb the sex undetermined in two individuals .. All the females were mature or gravid, and eight of the males were mature. Tne-mean standard length was 185.;04mm with a range of 106 - 235mm. The times of collection were from 1000 hours to 1600 hours. 21 Pclychaetes are the dominant prey of !1ullo!~ tlavolineatYl!; and were found in the gut contents of in all specimens. Bi valve molluscs and xanthid crabs rank second and third (Table 4),. Amphipods, isopods,tanaids, crab megalops and opisthobranch molluscs were ,eaten by 501 or more of the fisb. cyclopoid copepoda and colonial tunicates were each found in only one gut, and brittle stars in two guts.. The xanthid crabs consumed were mostly small individuals (1 - 3mm carapace width). Ocypodid crabs and portunids were larger (mean carapace width 3.87mm) but were infrequent in the guts. Worm tubes were found in one were not included in the IRI.. It is possible that broken worm tubes are included in the volume recorded as unidentifiable food.. The volume of sand was not measured directly as it was not easy to separate, and most of the gut contents contained very little sand. Guts with high volumes of sand usually contained bivalve molluscs and polychaetes; the sand may represent stomach contents of the prey and/or ·tubes .. - .t!yJ.l~.2H~JlaJ!olineal.Y.§ was the only species with measurable amounts of sand in the guts. The other four species examined had little or no sand in their gut contents. 22 TAB.LE 4 Ranks of food items of Mulloides flavolineatus All stations combined. Number of fish with gut contents = 18 Prey lEI Polychaeta 51.5 10.4 100.0 6190.0 Xanthidae 12.5 3.4 66.1 1060 .. 5 Bivalvia 5.8 4 .. 0 83 .. 3 816.3 Amphipoda Gammaridea 9 .. () 0.6 72.2 693 .. 1 1§.E~.Q<;hel}.a dubia 4.9 0 .. 2 66.7 340.2 Crab megalops 2.8 0.4 61.1 195.5 opisthobranch gastropoda 2. q 1.2 50.0 180.0 !!arnphug ost zu;:gasrgj. 2.3 0 .. 2 55.6 139.0 Sipuncula 1.6 0.4 38.9 11.8 Caridean sh.rimp 1.3 0.4 33 .. 3 56.6 Prosobranch gastropoda 0.9 0.1 33.3 33.3 Alpheidae 0.8 0 .. 2 33.3 33.3 Portunidae 0 .. 4 0.4 22 .. 2 11.8 Ocypodidae 0.4 0.3 22.2 15.5 Ophiuroida 0.4 O. if 11 .. 1 8 .. 9 ostracoda 0.2 .. 03 16.7 3.8 Colonial tunicate 0.1 0 .• 2 5.6 1.1 Cyclopoida Copepoda 0 .. 1 .01 5.6 0.6 unidentified eg9s .. O. LJ 5.6 2.2 crustacean fragments 1.2 61. 1 220.0 food .. 74.7 100.0 7LJ10.0 *Percent of total numbers, volume, and f.reguency of occurrence of prey in guts 23 No gut had less than five p.rey types with a maximum of ten. The mean was 7.7. The total number of prey types (larger categories, no·t species) was eighteen. No I.-elationshi p was found bet ween the time of collection and the number of recognizable prey (Spearman' s r = -0.12). The fish had either totally empty guts or food in the stomach and intestine. Fish caught at 1100 and at 1600 hours had empty guts, and fish caught between 1200 and 1500 hours had full guts. Thirteen of the 31 fish collected had empty guts. Sixteen families of polychaetes were found in the gut contents. Species consumed in largest nUlllbers were the onuphid ]otllri,a holob!:sl!£hj.~!A and the opheliid,lUsngia intermedid!. These species comprised approximately two thirds of the total numbers of polychaetes eaten by 11- .f1.a!.2J..iI).eat,!!§ (Table 5).. The remaining one third consists of 21 different species. Only seven polychaete specimens could not be identified at least to family. Apart from the Opheliidae, most of the predation was on .families of errant polychaetes: Onuphidae, Eunicidae, Nereidae, syllidae,Amphinomidae. Very few individuals of the family Capitellidae were eaten, even though this family was very abundant in the benthic samples. Most of the polychaete species found in the sand samples occurred at least once in the gut contents. 24 TABLE 5 Polychaete species in the diet of Mulloidesflavolineatus Percent of total numbers of polycnaetes in gut contents Opheliidae Armandia j.nt~£medi!! 34.98 Pgl~2E!h~!B~§ 2!£!~§ 1.08 onuphidae !Qth£i~ !H21Q.!tr~ncb!.!!.tf! 33 .. 44 Mereidae 7.09 Syllidae 4 .. 93 Eunicidae H~matQnsm§ 1!1li.£.2£n.i§ 3.39 ~U.ni£E sp. ,.46 l.Isi :Ihal.,Sm.ll,S. l'l!s'!'s.!ili .s.9.!~~ was the only portunid iden tifi·ed to species. Ocypodid cr abs included Q£.Illi?g~ sp. and ~jicr!a.ethalm.1l2 ?£Qn'!~J!:!:H~. Most of the amphipods were species of the family Gammaridae. .!!.a~J!9E.!l2 sp., ~'§fs sp., ]l::i,g.E!§S sp. and unidentified Gammaridae comprised 68.ql of the total amphipods consumed. Other amphipod species eaten were !.n.s.l!iID§tebbin,g!, 1llia~u~, andbeuco!h9~ sp. Of the identifiablexanthid crabs 57 .. 6% were?!:!Rtodi.t!s ~xau!.!!2. Tin: •• othe.r species were also distinguished. Thirty seven percent of the xanthid crabs were too small or too digested to be identified further. Isopods occurred in 561 and tanaids in 671 of the guts examined.. Howev;erthese animals are very small and contribute little to the total volume. Gastropods in the diet ofl1Ylliidei!!l.s.!.2J.i~~ty'§ included~Istic,!§ 1!.!!DA, ]!!.!im,S ~alfi,lIocb9-s i.n!u'!u§ and .Ri!r9-s!!i~!ia .b2etp!. The largest gastropods eaten had no shells or very small thin shells. These were treated as a separate prey category because oftha high percent volume and frequency of occurrence.. Large thiCK-shelled gastropods were not found in the guts..r1ost of the bivalve molluscs were S!?D1'!:!kI!Sgul,ys £.Ig.p..I,!.!I!£llim. other bivalve species found were ll.a.I.£a.llA sp •• £1§n.s be!lA, .I!t!li-pa oah.!!slllh LonoS! l!.a.!ai-l:~nsis and gouldi! £Q,Q,tei,. 26 Twenty-three of the fish collected were females, with 17 classed as mature and six gravid. The eight males were all mature. The mean standard length was 210.94mm with a range of 175 - 270mm. Crabs and shrimp are the first five ranked prey of .fll:!UB~p.f::lll.2lliillasqi..a1.Y§ (Table 6) • Ninety-five percent of the guts contained xanthid crabs and 651 portunid crabs. Unidentified caridean shrimp, alpheid shrimp and ~llnc.~.p~m!!i§ Fy.,gulo§..!!2 rank second ,third, and fifth .['especti vel y .,f.. l!ltl1i!sss:is!.!!§ was the only goa tiish species in this study eating ,B. cI!ULY!2§.lH~" There was little difference .in the firstfi veranks between stations. !hyn..shoc~.!!~t~·· was' not consumed at Stations 14 and 21 where the fifth ranked prey were crab megalops and R§~.9.Q§!Uti.l!s ocula.tSl rEspectively. only one .Rltlnchp9in~~..2claw was found in one fish at station 16 giving this shrimp a low rank for that station. Alpheid shrimp were probably all one species (ililUH!§ ?l:.S.E~'!) as only one kind of chela was found. Shrimp were listed as unidentified alpheids when a chela was not attached or in close proximity in the gut to the body of the alpheid. The fish found in one individual at Station 21 is tentatively identified as E.2il.2.9g!!!~ .Yil!.!~Iuiithe species 27 TABLE 6 Ranks of food items of Parupeneus multifasciatus All stations combined. Number of fish with gut contents = 20 Prey %N* %v* %F* Ill! Xantbidae 22.. 0 17.7 95.0 3771.5 unidentified Caridean shrimp 27 .. 1 1.1 75 .. 0 2160.0 Alpheidae 15.4 .3.4 80.0 1504.0 Portunidae 12.2 9.1 65.0 1384.5 Ehlncbino~et!§ rug~lQ§~ 4.4 14.6 30.0 570.0 Crab megalops 2.7 o. 1 20.0 56.0 Amphipoda Gammaridea 2.2 0.1 20.0 46.0 Polychaeta 1.5 0.3 15.0 27.0 Ps~yg.Q~gYil!s. .Q£J!!ass 0 .. 5 1.8 10.0 23 .. 0 ostracoda 0 .. 5 .. 02 5.0 2.6 f§il.Q.9.9~i.!,l§ sp. 0.2 0.2 5.0 2.0 Bivalvia 0.2 0 .. 1 5.0 1.5 Sipuncula 0.2 .. 02 5.0 1. 1 unidentified crustacean fragments 11.0 17 .. 0 80.0 2240.0 food " 33.9 80.0 2712.0 *Percentof total nllmbers, volume, and frequency of occurrence of prey in guts 28 of goby tbat shares a bUrI:owwith A!J2beus +-sei!.!· (Baldwin 1972). Definite identification was not possible because of digestion. Pour alpheid shrimps were found in the same gut. The portunid c.rabs consumed by g. !!mltifa.§£j.atu,§ all belonged totha same genus, lll.9.1am~!~.. Two species were identified: 1 .. .integrA and I .. ill~.§.Twelve species of xanthid c.rabs were eaten, with 44 of the 90 crabs found being l&zll.!l!.l!!~.J.a~!..!!.2. The polychaetes eaten were tbe glycer id fi!!gestes§~ll2!~' the ol)neliids !;g'!!~'pd.!a .i:nte.E1!!ed.!s and ,follonhg,J...!!lll§ n£!.Y§, and two nereid species. All twenty ,f. '!J!l!!.I§;§~.u!.l!§collected haa full guts. Fish were collected between the hours of 1000 and 1600.Tbe size range was 136 - 245mm, with a mean of 201.25mm. Ten of the fish were male, eight of which were immatur:e.Eight were female, four immature, two matu.re and two gravid. Sex was not determined in two individuals .. Xanthid crabs were the dominant prey, with nine species eaten (Table 7). seventy-nine of the 162xantbid crabs (LJ8.-8%)- were ?J,.e.E!odiJ!.2.5.!ll.2!.!!.2. Prey found in the guts of 501 or more fish were polychaetas, portunid crabs, aDd alpheid shrimp_ with the addi tion of polychaetes the first. six ranked prey of .f...a!:.!!l!!!L~'y§ J21~'y.£.Qsti9.!.!! are very similar to the first fivera oks of .f. mul tiiasc.iat:Y§ (Ta ble 6) .. 29 Portunid crabs identified to species were portunqs !2ngi~u!inosg§ and Iha!.!!itj inte.!!!._ Fgrtunus .. species comprised 57.1" of the portunids eaten •. Two fish ate the ocypodid crab ~croR!!.!lmu§ j::!lescopic9.~, and one a majiid crab. The amphipods, LIsidinaf?~!U!s and ~rio.ei§A· spo were eaten by one fish, as was the isopod la~a~thu!,!.·ostergaar4i", .. Polychaete prey species include an unidentified polynoid, NothriaholobJ:anchia!,§, two eunicids, Nematonere.i§ ypicorni§ and Ilni£! sp.,1N2tocirr!l§ sp., Ql!ce~1esselata, Capi tells £api t:;ata, and the opbeliids !Emspdi,g., iDliermedia and .fol'fopthjlmll~ 2:.\g!U- There were mo:re polychaete species consumed by!. mY!2sti9ms than hy .f. !!llJ)..ti: fasciatu! but fe·wer species than were eaten by .!1Jllgide§ gljvo!ineat.!!§. Fourtee.n specimens were collected between the hours of 1300 and 1S00.. One .fish collected at 1400 bours had -an empty stomach but with food in the intestine; the rest had full s·tomachs and intestines. The mean number of prey categories pe.r gut was 5 .. 1 with a maximum of eight.. A total of fourteen .recognizable prey types were found. Nine of the fourteen fish collected were male, eiqht of which were immature •. Three of the four females were immature. Sex was not determined for one fish. The size range was 183 - 240mm standard length with a mean of 212mm. 30 TABLE 7 Ranks o.f food items of Parupeneus pleurostigma All stations combined. Number offish with gut contents = 14 Prey IN* "V* IF* 1R1 Xanthidae 41.1 14.8 85.1 5304.e Polychaeta 11. '9 6.5 51.1 1050.6 Alpheidae 9.6 3.1 11.4 949.6 Portunidae 6.1 5.7 11.4 842 • .5 Crab megalops 4.6 0.2 35.1 111.4 unidentified Caridean shrimp 1.7 1.7 28.6 97.2 l1S!.c:ro ,2±h a!'Jl§ :t~ 1§s~5U~i'Y§ 2.0 2.9 14 • .3 70.1 Colonial tunicate 0.6 3.9 14.3 64.4 Gastropoda 1.2 0.2 21.4 30.0 Sipuncula o. '9 0.3 21.4 25.7 Ophiuroida 0 .. 6 0.3 14.3 12.9 Amphipoda Gammaridea O.g 0.2 7.1 7.8 Majidae 0.3 0.4 7.1 5.0 l!i.'p'antbY.tA ost,-!g~a!1S!i 0.3 0.1 7.1 2.8 unidentified crustacean frag.ments 12.2 13.6 18.6 2021.9 food • 45.5 100.0 4550.0 *Percent of total numbers, volume, and frequency of occurrence 0.£ prey in guts 31 Because polychaetes were so important in the diet of Nullo1:.de.§ !lSl'!.2J,ineg!.J!§ and the benthic samples a:re a good estimate of the abundance of polychaete species in the sand, dietary preference using the Proportional similarity Index {PSI} was calculated for polychaetes in the benthos and the diet of 11- fla.yol;ineqtJ!§ at the stations with largest number of fish with guts, i.e. stations 14 and 21. Selective feeding in J!i!!:..l.m!Ul~§ !.yltiill£i1!!J!.§ and .f. £!g.Y:!:.2§~.~~HI'!l! is harder to estimate because the numbers of crabs and shrimps, important prey fo.r both species, are underestimated in the benthic samples. Only two species of xanthid crabs were found in the sand samples. Twelve species of xanthid crabs, plus three species of port.unids and two species of ocypodids, were eaten by g .. .E.!§l!,!,Q~ti9.!!!A and g. ulii fass;ia!J!.2'" The values of PSI for polychaetB species at Station 14 were 0.1167, and 0.2695 for Station 21. It Station 14 461 of the total numbers of polychaetes eaten were Nothili l!.2.!2.!?!:anch:i-aJ;..£l,33.5% were !!:!n~ndiSl j.p.te!!~dij:! (Figure 2). In the benthic samples these two species compI:isedl.~ and 3.5 percent respectively of the total numbers of poly chaetes. Seven ty-th.ree percen t of the polychaetes in the 32 sand were a species of capitellid but this species comprised only 0.61 in the diet. Syllids were 15.41 of the polychaetes in the benthos and 2.91 of the gut co.ntents. Several species found in the guts were not present in the sand samples and vice versa. ~.bfi.J..ina sp. ~.!2o.t:vill~,£! sp., Risi.Q.nid~ns ,j..!Hti~ and .£isi2~ s p. were not found in the gut contents. Nf;!matonerra.i§ :gllic~,. it.!U!i£g sp., lX~!dic.§ sp.,. ~aEi tell,£! capiti.!1!1.a, p'a§! hriUA.£hus sp., !£!t2mastns sp., GI'y£§rs !rui§illU, ,!.in.2.El!~£!!§ sp.,Ph!.llocl;~toRteru§ J!~r,£iJ..ll, and an unidentified hesionid were not represented in the sand samples. 33 Figure 2: polychaete species in sand and guts Station 14 N 1 " / " r '- / I -~~ 16 c I ,In • I J f G {.... ,---- ... , ,'" - -, \ \ I .. , I I I I ~ II I:'tI~ i , _--...--:;.,;;.::;:: I I \ . , \ , ' OJ1- ---:fl~-+-'I 2 _---,~ km 35 Similar results vere found at Station 21 (Figure 3). !otjr~~.s!t219RIsnchis!J! and !!!~!l,giJ! ill~£.!~!iJ! compcised 56'% of the polychaeteseaten at this station, but only 3.1% in the benthic samples. Thirteen percent of the polychaetes eaten were Nerft.i§ ~!.J.iaA' and 7",LJ' were 51'l1ids3 A species of Dorvill!ia comprised 12.8% oftha polychaetes in the sand, and 4.4% oft.be gut contents. Species that represented more than 1% of the total number of polychaetes i.n the guts were Nema!~ili .!!.Dis;:orni~ (3 .. 01), Li.nopheru,2 sp (3.8%), ~Y£H?th~~.Ei£!.Y.§· (1.7%), capitellids(4. 7%) and spionids(1. 3%)" As at Station 14 g..pic!"y,§· was consumed in approximately the same proportion as it occurred in the benthos.. The percentage of capitellids eaten at Station 21 was larger than at station 14, but the numbers eaten were still low compared to their abundance in the benthos. 36 Figure 3: Polychaete species in sand and guts Station 21 45" 45 Station 21 o Guts ~ Sand 40 35 .. II II 30 a ..r:. u >- -0 ~ '0.. 25 II ..Il E ::> Z -0 20 ....0 19" 0 c: II ~ 15 II ~ 10 5 0 .EL II II a .. .. Q. II .. ::> II ., II II a a a ..., a :: ~ .. ..co. .~ .:;; -a -a ~ u II ..r:. c: ~ -a ..c II "0.. ·E a a "c :~ a. ~~ E =>- 0 c: .. .! a.: 0 0 Z ." :;c "0.. ::> Z.. "ii 0 c: II) w a .... .< U 38 Dietary overlap (PSI) between g .. E+'~urg:stigmg and g. 1!U!1!ifasc,j.~1.Y2 was 66.6% calculated using the INI (Table 8). Most of the dietary overlap between ,E. !tultif.s§£i~.tus and g. ,Ele,gros,t..is!!g is based on xanthid crabs and shrimps. Xantbid crabs are the top ranked prey for both species. Caridean shrimp are a more important prayforg .. .!!.y:1ll.:. ,fasci~, and polychaetes are more important for g. 2l~\l.rosti51'!s. !l!lI.n~.!JJ~ £'ygulo~!U? rankedfi.fth for ! . .!!Y.llifa-Sicla!l!§but was not eaten by g • .E1~M~.9.!A. The other prey eaten only by g .. J!YJtj.!s§cj.,at.,Wi (fis.h, stomatopods,ostracods, and bivalves) were relatively unimpcrtant prey. Similarly prey items eaten only by g • ..El~.YFos~ti.g.!!!.~, were relatively unimportant to that fish species .. TAB.LE 8 Dietary overlap between goat fish species at Midway overlap calculated using Proportional Similarity Index 100.00 4 t. 00 100.00 28.15 66 .. 59 100.00 39 Dietary overlap (PSI) for tlgllg.ides lliyoline4£.!!2 with garu.E~.Y§' El~.!!rqstigli was 41..0% andwitb ~ • .!ultifs.§£!.g,!'y§' was 28.75'; Crable 8} ..Xanthid crans are important prey for all three species. The mean size {carapace width) of crabs eaten by each species was 3 .. 85mm forg .. .e1e'y&'Qstig.!!Ul, 5.15mm fO.r g_l!ultifa§qi?tp..§, and 2 .. 67mm~for 11- lifl.!21iAeatYe-To test for differences in the size of crabs eaten by each species an analysis of covariance was performed on regression lines of crab carapace width on fish standard length,. Within each speciesthe.re was significant regression of crab carapac·e width on fish standard length. The standard errors of the slopes were large so that no significant difference betwe·enthe slopes could be shown. The analysis of covariance show·ed no difference in the adjusted means at P).05. Dietary overlap between .f • .E,QrEhlreq§ and 11- .!.i.!l'!5r.9!~ll.§i§ and the other three species was not calculated because the high proportioD of empty guts in .:e.~ltlreu§ and 11_ vanicpls;nsl§' resulted in a very small sample size for prey items. Several authors (Suyehiro 1942, Al=Hussaini 1946, Thomas 1969) have stated that little or no feeding occurs in goatfishes during spawning periods when the gonads are large relative to the size of the body cavity. Inthe case of the species collected at Midway empty guts seem to be related more to the time of feeding and of collection than to 40 gonadal size. Gut fullness was independent ofwbether a fish was gravid or not (G-statistic = .128, DOt significant at P>.05).. Five of the six .f.E9.rphlr~.!:!2 specimens with empty guts were immature, as WElre half of the 11. ,!sD-.ig~ l~i§" All 1!= .t.l!iY9.1in~a111§ collected were matu.re,. and 58'1' had full gut contents. Pull stomachs and intestines were found in individuals where the gon.ads occupied one half or more of the gut cavity. The most abundant animals in the benthic samples were polychaetes a,nd molluscs. The total number of speCies, excluding molluscs, was '12 (Table 9) • Forty-th.tee species belonging to 22 families of polychaetes were found. One hundred and twenty six mollusc species representing 50 families were found in the 25 ml subsamples. Most of the animals were small, the largest being the mole crab .Hi,E!!,! ~acif.i.£S and the fish fu§.ull.Q!I~§ £Q2£!!.i. 41 TABLE 9 Characteristics of sand samples at Midway Numbers ar,ethe means of three 2 litre samples/station STATION 1 10 14 16 21 Number of species 23 17 18 14 16 Number of individuals 565 100 615 91 275 Number of polychaete species 15 9 10 8 11 Number of polychaetes 484 57 226 31 108 Diversity fl' 2.09 2 .. 14 1.77 1.79 1.48 Evenness J .67 .78 .49 .68 .55 Pew crabs or shrimp were found in the sand samples. Shrimp were present only in samples from stations 14 and 16. Xanthid crabs, a total of five, were found at stations 10, 14 and 21. One mole crab, t!!.E.Es.e.§..£:if~£.9:" was found at Station 10. The isopod ~ll!.hl1Is ,2stfZJ:.£lp..a.IS! was found at Stations 1, 10 and 14, with most of the individuals in sample 1-3. Harpacticoid cope pods were found at all stations, in varying numbers. One cyclopoid copepod was mpresent at Stationu -2t; . -The tu.bed-wei:ltng tanaid 1.i12!Q:£heli,g Aubia occurred only in samples from Stations 1, 14 and 21. Gammaridean amphipods were most abundant at Station 10, with the common species being .tla~F'p; sp. and ili§J!!.2.E!!§ sp. Othe.r species identified, but represented by only one 4.2 individual of each species 'We.r ,e Leucothoe sp., EJ!.2iroid~ ~i.Elon.Ix and lluu.sID! ·· ami!&.. Fourteen amphipods could not be identified, because the third uropod was missing. They are probably all species of the family Gammaridae. polyclad flatworms were collected only at station 10, the site with coarse sand/rubble substrata and high wave energy_ station 10 was the only site where nematodes were not relatively abundant. A total of seven nematodes were fou ~nd in the three samples taken at Station 10. Two small fish, g!stallQp.lt~.§CO~, found at Station 10 are species of the family Trichonotidae, the sand di verse They dive into the sand when disturbed, (Gosline and Brock 1960) but do not construct or live in burrows in the sand (w.J. Walsh pers. comm.). Sipunculans were collected in small numbers at all stations. The phoronid,fltQ£Qll!.2.E§{l.mmo,Ehilawas present only at station 16. This is a new distributional record for this species in the Hawaiian Islands. Pol!chae!~~ . A total o.f 44 polychaete species were found in the fifteen samples. Sample 1-3 had the greatest number of 43 polychaetes! 22 species and 723 individuals. The smallest number was found in sample 10-2 with fifteen individuals from six species. only three families. spionidae. Phyllodocidae, and Capitellidae, were recorded from all five stations. Eight families occurred only at one station. and two families from two stations only.. The numbers of capitellid polychaetes were very variable between stations, from five to 498 individuals per station. Neither spionids or phyllodocids were very abundant at any station. station 10 was the only site with the tube dwelling onuphidl!£ll!ri!!lliobrj.ngiisli in any quantity, although this species was also found at Stations 14 and 21~ No species of the family Opbeliidaewere collected at Station 10. Species of the family Pisionidae were found in all three samples at Station 10. This family is previously unrecorded from Hawaii. sample 10-3 had the highest Ht valu~. 2.34, of any sample. The families that were numerically dominant at Station 1 were Chaetopteridae, Cirratulidae, syllidae and Eunicidae. The large numbers of chaetopterid species may indicate that the samples were taken within chaetopterid 'mounds' (Bailey Brock 1979). A considerable amount of wood and algae was present in sample 1-3. species found only at Station 1 vere l!.I2£.Q ide2 ~.h.Yacan.!!u! ,~~!:J2'yla .!~.IlJI.icu;tar i~ I ;Eu!,li£§ !.i..!J. .s!!.s, Q.lI~.t,S 1essellli, and the besionid 19,Q.9i!!:.1F~ Euge't;tensi,§. However remains of QlI£lls !~1?selatE and hesionid species were found in the gut contents of fish from station 14. Apart from one individual of ,£i,Fr:ifor!!ia §emicinc!1 from Station 21 all specimens of this genus occurred at station 1. syllidswere not collected at Station 16~ although this family vas abundant in all other samples, and is a commonly occurring family in coral reef polychaete communities (Hutchings 1974, Reichelt 1979). Although not present in the benthic samples ~~.1§ sp. and an unidentified polynoid were found in the gut contents offish speared at Station 16. The families Bunicidae, Cirratulidae and Chaetopteridae, which were abundant at the other stations, were absent at Station 14. Two species of the family pisionidae were present in samples 14-1 and 14-3. ,.1-inq.E~~ sp. and li..Y.!!.1£@ sp. we.re present in the gut contents from Station 14. Tube dwelling species such as chaetopterids, spionids and lio,:tP.I;;ll .b.52!ill~.£J!i~tE were represented by relatively few individuals at Station 21. This was the station with the most individuals of .!2.QIX1~ sp_ andlfer~i.§ £.2.£lll.iaa- This last species is considered intertidal; Station 21 was the shallowest site with a depth of 1 - 2m. 45 Di versitI 914 siailar.j.!.I a!liISis Diversity (H') values ranged from 0.91 in sample 14-3 to 2.~4 in sample 10-3 •. The Ht values were most variable between samples at station 14, from 0.91 to 2.31. Station 1 had the most consistent diversities between repl.icates, with H' values of 1.95, 1.99 and 2.33. The mean diversity pe.r station (i.e. mean Ht values for three samples) was lowest at station 21, 1.98, a.nd highest at Station 10,2.14. Stations 14 and 16 had almost identical mean H'values 1.77 and 1.79 respectively. Station 1 was the closest to Station lOin mean di versi ty with a value of 2.09. Dendrog.raphs were constructed using both qualitative (i.e. species presence/absence) and quantitative data, as differen·tresults may be obtained (cf. Stephenson ~. U 1970). The qualitative data (Figure 4) show low similarity values between stations. The highest value (411) was between samples from stations 14 and 21 (14-1 and 21-1) '" The most dissimilar sites were Stations 1 and 10, connected at 15~similarity. Station 10 was mostly rubble and coarse sand and Station 1 was very fine silty material. 46 Figure 4: Similarity analysis with qualitative data Numbers indicate percent similarity at fusion levels r__ ~PI3~4~------~1~0~-~3 .10 -2 .-__-.J28 I 10 -1 ~ __~f414~3~------21~6~-~3L ... I II- 16 -2 Ir------.l 3 3 16 I - 21 - 2 ~~~6~------~2Ll-~3~ t------.J 3 2 I 21 -] 15 21 1_---'41 14- 3 r n 52 IL- 25 I 14 2 50 I 14 -1- _ Ir--- ...... --,...~~~r5~2L---;------_~I~-~3 I 1-2 1____ ~36 1______~I~-~1 48 If clusters are defined on the basis of 50S or greater similarity, the dendrograph showstwel ve clusters, ten of which represent single samples. This would indicate considerable heterogeneity within and between most stations. Onlytbe three samples from station 14 are clustered together at the 50" similarity level, and two of the three samples f.rom Statio.n 1. The dendrograph .resulting from quantitative data analysis (Figu.re 5) shows eight clusters at 50" similarity, only three of which are single samples. The only consistency between quali tati ve and quan titati ve analysis is the large differ.ence between stations 1 and 10, which are linked quantitatively at 81 similarity. The similarity values in general are higher with quantitative data. Wi·th qualitative data ·the samples are clustered according to station and grain size, with stations 14 and 21 linked. With quantitative data the pattern is not as clear; the three samples at station 21 are linked at 661 similaJ:ity, but the samples from Stations 14 and 16 are mixed up. 49 Figure 5; Similari ty analysis with quantitative data Numbers indicate percent similaI:ity at fusion levels 10-3 28 10-2 51 10-1 . 14-3 54 14-2 - 21-2 . 66 2 1-3 49 76 21-] r--- 23 32 16 -3 8 19 . ]6-2 58 16 -I I--- 37 , • 14 -I -- 1-3 ------~------~~ - -- ~------56 1-2 69 I-I IV DISCUSSION The prey items eaten by goatfish species at Midway are very similar to those eaten by the same species at Kana and Oahu Hawaii (Mahi 1969 r Hobson 1974).. tanthid crabs w'sre the dominant prey of ~E~~.Y§ E9fEhI.t:!u!§f.rom Midway and Kana, and in fish from Oahu of 110 - 180mm standard length. In fish large.rthan180mm fish become the co-dominant prey with xanthid crabs for l .. .eQE2.!.!Ieyp on Oahu (Mahi 1969). No fish remains were found in the Midway gut contents, although most of the .f .. 2,Q!..el!..!l£~.Y~ with recognizable gut contents were larger than 180mm. The importance of fish in the diet of large !!. R.2£.eh.lJ;~'y§ on Oahu may reflect utilization of a seasonally abundant prey, e.g. a recruit ment event of larval fish to the reef. However the collection time on Oahu (June to November) overlap the Midway collections which were made in August. If there is a seasonal peak in the abundance of fish as prey it should show up in the diet of the Midway samples. Echinoderms were important prey for !!.ull.£i,g~§· ,!~;gl:e-nsi:§--at-··K~:rna-,--nawa~ii-1Hob-sun--J974rnuu-t.--wen;:r not n found in the gut contents of the Midway fish. otherwise the diet of It.y'anicolensi.§ was similar at Kana and Midway. Marginellid gastropods which comprised most of the gastropods eaten byll .. .!.2Jli&.2.!§!l.§i§·at Midway were present - 51- 52 in the sand samplesthougb. not particularly abundant. Perhaps their abundance in the diet. of !. 'yanicQ!~nsi§ reflects nocturnal activity of this gastropod. ].~!:Y.2~n§:y.§ 129.rehlrsy§ and ~J.J.o!.4es!s!i£.Qlen.2i2 are both nocturnally active (Hobson 1974) so that fish speared during the day have a higb percentage of empty guts, resulting in a small sample size. There is some dietary overlap between ]il!!12!i~'y§ seen feeding together (Jazwinski pers.comm.) If food is limiting then the diets of these two species would be expected to be di fferent.There was no significant difference in the sizes of xanth.id crabs eaten by the two species of ?qrUE!!!!g'y'§ and subjectively there was no differ·ence in sizes of other prey ite.ms.. The size distribution of xanthid crabs in the gut contents probably reflects the size distribution of these crabs in the benthos.. Dietary overlap does not necessarily imply competition for food (Colwell and Futuyma 1971). Goatfish species at Midway are probably not food limited, as suitable prey are available in the benthos and other fish species adapted to feeding on sand infauna e.g. rays, flatfish, are rare or absent at Midway. 53 Lack of overlap between .f.iirupe»~.u~ J!y.lJ:.ifasciatJ!§ and .f. 1!leurosti~.l!a with 11'l1l.l2!g~ ··lla.!olin~alJ:!§ is a result of differences in the dominant prey of the three species. Polychaetes are the dominant prey o.f 11. !l~gl;i.!le.a!,g§ and c.rabs and sh.rimp are dominant in the diet of the two species in feeding behavior. ~J!!loig~!>li.§.j!()li!fea:.t..!e forages more over open sand and digs a deeper hole while f. multifas::. £i~!J!§ and .f • .2leur9s!..!.9.!~tend to feed closer to the co.ral and rocky substrata, and in sand patches on the reef (pars. obs.). Xanthid crabs would be more abundant closer to the coral reef than in open sand. Subjectively the diet of overlap that of .f.J2lStJ!!.Qsti.!l!.s and .,e • .multiJa.~s;!s:!y~than that of 11. :ela volineaiY~ because of the dominance of xanthid crabs. ~J![!en!U!.! eor,E!!':U:;!J!§ ate larger crabs than the other two species, but the fish collected were also larger .. of the animals found in the sand samples (Table 4), implying that this species is eating available prey as encountered .. The Proportional Similarity Index (PSI) calculated on polychaete species shows dietary specialization, especially on two species of polychaetes !!:!aq,,gis. intermed1,S and Not.hfia p.o1.2.p.I~n£!!.!ata (Table 5). The relative abundance of these two species in the diet is greater than their relative 54 abundance in the sand samples. Species of capitellids which are very abundant in the benthos constitute a relatively small percentage of the diet. The consumption of some species increases as their abundance in the sand increases e .. g. nereid and dorvil1eid species were more abundant and were eaten more at Station 21 than at station 14 (cf. Vivien and Peyrot-clausada 1914). !.Q!hri~ hQlob~ancJ:li.a:tath.e onuph id polychaete, builds a permanent tube covered with sand grains. This species has been previously recorded only from deep water habitats in Hawaii; all deep water species of !.!2llii1! are sessile (Fauchald and Jumars1919). Other sessil,e onuphid species e. g. J2.i:.2.Q~!ll species are gregarious and form mounds of vertically arranged tubes and compacted sediments, with an associated community of tanaids, amphipods, and polychaetes, etc (Bailey-Brock 1980). Onuphids such as .N2'!:hIi~ and !t!o12atIS species are surface feeders, and are capable of retracting into their tubes when disturbed (Fauchald and Jumars 1979, Hulberg and Oliver 1978). It is possible that the concentration of animals and/or fecal material aI:ound the tubes of ,!g:Hlrif1 l!.Q+..o~r1!Dchlat,e:. provide a means whereby l1Jlll.Q~§ lli!!oJ.in~asu 'keys in' on the presence of potential prey (Holland pers. comm.). Opheliid polychaetes do not build tubes, but burrow in the sand.~IIqsn,gi~ .!lJill~.iA is active at the sand/water 55 interface,feediog by ingesting sand grains and associated organic matter (Fauchald and Jumars 1979). This behavior would seem to make this species vulnerable to predation by fish feeding with.in the sand. Larger species of capitellids e.g.. !Q.t.Hma.2!~ and nas!branpb~J'§ species build deep burrows and are not active near the surface, but £s.R!~ll.s £SE1,ta!£! burrows at or near the surface" This species was eaten bY!l!!J..~~g~~ fl.s'!9.1in~atY!! more often than other capitellids. The depth distribution of the capitellid polychaetes at Midway is unknown, due to sampling constraints. It is likely that capitellid species 2, like £. £SEij:a;tg is active near the surface. Individuals of capitellid sp. 2 are very small and may be energetically • unattractive' as food. The gut contents of the goatfishes collected at Midway may contain prey eaten at locations other than those of the sand samples. However, every effort was made to spear goatfish while they were feeding, and species were observed feeding at the locations where the sand samples were taken. speared while schooling_ Heavily ornamented tubes such as that of the chaetopterid .f!u~l!o£h~o.Et~ ~£lil!i are apparently some protection from predation as only the heads of this species were found 56 functi.on as predator defenses f.or the worms and the fauna associated with the tubes (Brenchley 1916, Woodin 1976, 1978). Regenerating heads of ,Q. l~,.gckaI!j.from Oahu, Hawaii are evidence of predation on the anterior portion of this species (Bailey~Brock pers .. comm.).. Regenerating palps were also found in chaetopterid species in this study.. onuphid polycbaetes extend some distance out from their tubes when feeding (Fauchald and Jumars 1(19). Wbo1e or large sections of NQt;hr;:j.a W.Q.P.IAn Hu1berg and Oliver 1978). The apparent selectivity of ~. t..!?volj.neatu,§to feed on certain polychaet.e species is more a reflection .of the biology and behavior of predatol:' and prey than real selecti vefeedin g. Goatfisb are adapted for locating prey that ara undetected by other fish, and for capturing prey that are 57 sheltering in the sand (Hobson 1974). This is demonstrated by the incidence of !!h.!Dchocinf:teprllqulos'y'§ in the diet of ,Farupene'y§ Iiillltifasc,lS\;!y§ at Midway.. This shrimp is nocturnally active and was the most abundant invertebrate on night transects at Puako, Hawaii (D. Walsh pers .. carom.) • .f.Y.Y..E6.!!!a'y'§ .!u]J:i~ascis1l!.2 at Kona, Hawaii was aa ting stenopid shrimps (Hobson 1974), which are also nocturnal animals. The incidence of large shelled gastropods in the diet of goatf ish species is constr ained by lack of s·trong teeth and crusbing dentition (AI=Hussaini 1946, Suyehiro 1942). Crabs, even large individuals, w,ere rarely crushed in tbe guts, wbole carapaces often being :found close to tbe rectum. The soft body parts of crustaceans arB apparently digested after the legs and/or abdomen a:re broken off. There was no relationship between the number of empty guts and the number of gravid fish at Midway. Fish species that show parental care may reduce feeding levels during spawning periods; there would seem to be little reason for broadcast spawners like goatfish to cease feeding while spawning. Perhaps the incidence of empty stomachs in spawning fish in other studies (Suyehiro 1942, Al=Hussaini 1946, Thomas 1969) was coincidental. Most of the polychaete families collected at other Pacific locations e.g. Oahu, Hawaii (Bailey-Brock 1919), the 58 Cook Islands (Gibbs ~ a1 1975), and the Great Barrier Reef (Hutchings 1974, Gibbs 1978) were also collected at Midway. several genera, and scm.€ species e. g. l!emato!!Zl.!'~i§ llDic,2J;ni§, were common to two or more locations indicating a wide distribution for many species of polychaetes (cf. Kohn and Lloyd 1973). The numbers of families, species and individuals of polychaetes collected at Midway are comparable with those of other Pacific areas such as Australia (Reichelt 1979, Gibbs 1978, Hutchings 1974) and tbe Coot Islands (Gibbs 1975). Little is known of the distributions of some oftha other animal taxa found in the benthic samples. The isopod, ParapthllJ;!! .Q§i§:rg~2lliwas described from the Hawaiian Islands (Miller and .Menzies 1952). BoUt the tanaid 1&.E15!£~lii\ gyp-ia a nd the xanthid crabLe2t~i~ ~J:arq1J!§ bavea wide distribution in the Pacific (Edmondson 1962, Miller 1940) and occur in sand and coral samples from other Hawaiian islands. Soft-sediment samples from the Great Barrier Reef (Reichelt 1979) yielded 26- 29 polychaete specimens/litre, with six to eight families represented~ These numbers a.re comparable only to Station 16 at Midway, which had eight families of polycbaetes and a mean density of sixteen individuals/litre sand. Station 10 had a mean of 29 individuals/litre but fifteen polychaete fa.milies were represented. Samples from the other three stations at 59 Midway had larger densities and more families of polychaetes than the Australian samples (Table 8) • The diversity (R' = 2.65) of the Australian fauna (Beichelt 1979) is not included in the range of Ht values found at Midway, 0.91 to 2.34. The higher diversity of the Australian samples may be related to the high evenness found, J = .96 (Reichelt 1919). Evenness at Midway was lower, from .34 to .82. The numbers of polycbaete species from Oahu, Hawaii (Bailey-Brock 1979) are higher (15 - 22 species/sample) than at Midway with 9 to 15 species/sample. Diversity is also somewhat different at Oahu, H' = 1.44 to 1.52, although there is some overlap with the diversities of the Midway samples. The corers used in the Oahu study sampled a larger area than those used at Midway, which would affect the numbers of species found. Higher species diversity have been found within mounds created by aggregations of tube dwelling polychaetes (Bailey-B.rock 1979, Woodin 1976). Chaetopterid polychaetes were most abundant at Station 1 which bad a mean Ht of 2.09. Slightly higher diversity was found at Station 10 at Midway, mean H' = 2.14, where the samples were coarse sand and rubble • .Hot.h!:is l!.Q!Q!lIsUl£his.1A was collected in intertidal samples from Low Isles, Australia (Gibbs 1978). This species probably occurs in Shallow water at Midway because of colder water temperatures than in the high Hawaiian 60 islands. No data are a vai lable on water temperatu.r:es of the Australian locations. ______Nothria holobranchiata • I... • ... ____ was most abundant at Midway at the station with the greatest water movement (Station 10). This is the opposite of the situation with !.21~ ili.9l!.!!.§ in California where its abundance was negatively correlated with wat'er mOVEHRent COli ver ~ al 1919} .. The numbers of individuals and species was variable between replicates at stations at Midway, as were diversity (H') values. Reichelt (1919) found similar heterogeneity between sand samples from the Great Barrier Reef. The physical instability of soft sediment substrata and disturbance due to factors such as wave motion have been considered to contribute to localized variability of infauna (Oliver at .a! 1919, Reichelt 1919).. Tube dwelling species such as chaetopterid and onuphid polychaetes contribute to sediment and community stability by binding and trapping sediments,tbus creating a more stable environment (Bailey- Brock 1979, Virnstein 1919).. Sediment type is a significant factor in the distribution of species in soft-sediment habitats (stephenson,!U.a! 1910). Water movement is also important and is linked wi th. sediment s1 ze (Southward 1951, Oliver ~ al 1919) .. Differences in species composition between stations at Midway probably relate largely to the differences in the sand grain sizes and water movement. V CO NCI.USIONS Goatfish species at Midway Islands are generalized feeders, eating mostly small crustaceans, polychaetes, and bivalve and opisthobranch molluscs. Polychaetes weretbe dominant prey of 11\1lloides i'!syoli,!le,gtu,::; withxanthid crabs second in importance. Kanthid crabs and shrimps were the dominant prey taxa .for gaI.Y.E~n~J!§!ll\1Jtifa§£!~!.1!,2 and ,f. lieurpstig.!!2. Po1ychaetes were relatively important for of • .el~.!!£o§1ig!s. but less so for i.. mul!ifas~j.a!!!2. The sample size for Parl!J2~neM J2QJ;.Ehn::~l!§ and Jjy,ll;oidi!§ ,!api90l§n?!e is small becallse of the nocturnal activity of these species. Xanthid crabs are the dominant prey for the latter two species with 11 • ..!.s.n!£Ql~n~j.s also eating small gastropods. There was some dietary overla p between gart'U!SUl~'!!§ .!R.!ll!ifasr;!i!tu~ and i.• .EleUr2,2!ill~, but less overlap in diet betweentheset.wo species and f'lullQ~desflavoli,!les:tl!§ .. Although xanthid crabs were important prey for all three species no difference was found in the size of crabs eaten -by each species. -Larger fish - do eat larger crabs, but they also consume many small crabs, contributing to large variances. Differences in die-t bet ween goatfish species at Midway are the result of differences in feeding behavior. ~g;I..!..Qjgfa.2 lli.!olineatJ!§feeds more in open sand and digs a - 61 - 62 deep hole. This species is eating more polycnaetes and sand dwelling infauna than i.!!.Yllifi.s<;j~tus which forages closer to the reef and in shallow sand patches on the reef. The feeding behavio.r of ,f • .E.!~.l!ros!.!g!s· appears to be inter mediate between that of 11.. i.l.s.!2ll.neatA§ and ,g. !Byl!.!=. fasci,iitlls, accounting for the importance of polychaetes as well as c.rabs and shrimp in the diet ofi• .2J.~!!.E.2~t:j.gJ!!i!. The diet of g • .E.2!:.£hll~~ andl'l • .!~nico!~11!i..§ may r·eflect the nocturnal activity of their prey. The small sample size for the gut contents of these two species mates it difficult to draw definite conclusions. overlap in resourc's use does not imply competition (Colwell and Futuyma 1971). Food may not be limiting to goatfisb species at Midway. 'Ths.re ars few other fish species feeding consistently in the sand, and data from the benthic samples indicate that suitable prey is available in the benthos • .t!J!.!12lli.! fl~!.!.n~.s!J!2 appears to be showing positive selection for certain polychaete species and negative selection for others. The capitellid polychaetes which were negatively selected were extremely small, making them energetically unatt.racti ve as food. 1!Q.thllil!QlQY.an£h i.s!.! and Armang.!.!! !~t!!F-II!eg!i!i the two polychaetes which comp:rised two thirds of the total numbers of polychaetes eaten by 11. flayoline.s!.!llh are surface acti VB, and in the case 0 f 63 !. illtermeg!a, lack a protective tube •.. ,!,otb!U" holoj}ransthiAta· lives in a permanent sand g.rain covered tube whicb may be less protective than the more heavily ornamented tubes of othel: onuphid species (ioodin 1976, 1918, Brenchley 1976). It is probable that the feeding activity of 11.flavolinea!n may force !.holobF~!Ht.~iA!..q to leave its tube. This may account for the presence in the gut contents of whole or large sections of worms. Mutloid~§ flaI5!lipeittY.§ is probably best described as an 'active generalist' (Birkeland and Neudecker 1981)tban a specialized feeder •. Goatfishes arepa.rticula.rly well adap·ted to seeting out cryptic prey or anlmals buried ln the sand, which would be unavailable to visual predators (Hobson 197~.. The presence in the gut contents of nocturnally active animals e.g. lrhync.iocin~tes'[l!gulo~i13confirms this. targer crustaceans and large hard shelled gastropods were mostly absent from the gut contents. The feeding morphology and dentition of goatfish species limits them to small and/or so.ft-bodied prey (Hiatt and strasburg 1960, Al=Hussaini 1947). There was considerable heterogeneity between and within sample stations at Midway.. Reichelt (1979) found similar heterogeneity in soft sediment samples from the Great Barrier Reef, Australia.. The depth and sediment type varied between stations at Midway; this may account for much of the 64 heterogeneity (cf. Oliver ~ .91 1979, Southward 1957). The polychaete familIes, and some gene.r a and species.. found at Midway were common to other Pacific locations such as the Cook Islands (Gibbs 1975) .. Australia (Hutchings 1974, Gibbs 1978) and Oahu, Hawaii (Bailey-Brock 1979). This is more evidence for the widespread distribution of polychaete species in the Indo-Pacific region (Kohn and Lloyd 1973). The location of Midway Islands is approach.ingthe northet:D 1imi ts for coral reefs .. and water t·emperatures are colder than in the high Hawaiian Islands. Some species which are restricted to deep water in the high Hawaiian Islands, e.g. the polycbaetetJ,2t.!.rris· hol~.!is!.S and the gastropod ..a!illlocer9-§§'ybSlnnulatym, were abundant in Shallow locations at Midway_ Appendix A SPECIES IN BENTHIC SAMPLES - 65 - 66 TABLE 10 Molluscs in benthic samples Station 1 Numbers of individualsl 25 ml sample 1-1 1-2 1-3 Trocbidae .!2anilia~!l~lif.Ql;l!!j,s · · 2 ,. • 'l'urbinidae 1~.et.Q!,hIPs; 9!)9j.ilSl • • 1 1· . r,g~.fi.£i!l~.u .. .. 1 Pbasianellidae ~rico!i.a .!s;!j.~!!j,li§ 3 6 31 RissoidaeM§rel.!n.§. ~E .. .. 2 M. wanawana 3 3 1 j. iiiii~Ii • .. 1 ~2inal!!i!!o~9'!!s; " 2 " R• . turricula • 1 ighiictZIeIIA !:£iticea 1 • litiici!upa marl!!.Ql;.s1A 7 6 28 Paraskielabeetsi • 2 6 Vermetidae _. --- 1 " 1 Caecidae ~ecum·· §~.ej.~.D!.Yl!! 1 1 Dialidae l!iili .!s£:iA 7 1 18 .Q.. §£g.eJllo r.YJl! 1 ce!:Uhigi,g.! ~.!a!:.!.!!!.!l!l 2 3 Ceri thidae Bittitlm n12!y.! 43 • l!.. im12enflen§ 6 !!i t ll.!Ul .§2. 2 9 Triphoridae 3 2 Eulimidae .l!ili.i:§ sp. 1 .. 1 Calypt.raeidae ~r?pidu.!A A£.!!J&g~ .. 2 Buccinidae • .. 1 Columbellidae ~!uui~a !"Yr;:.ur!,DA 2 Marginellidae Q.£:a,nu!s sa.nm£~lli2 1 ganuli,n,g .!i!I~ 12 Costiel1aridae !exilluJ!! sp. 1 'l'ur.I:idae MitrolumlH! J!!§lls 2 pyramidellidae Plra!!!g~lli sp. 6 .. - ]llID!!2s . ingi£:2- 3 PI:£SlJ!!i.nAQ.2g~ 2 ScaphandridaeActeocil!A llg,niiSlnsi§ 1 1 .Atyidae .Pinill.!§ ~itSlI 2 1 siphonariidae .¥l!!liamis {adis!;A 2 Pteriidae Pinctada radiata . • 1 pectinidae--pe£liill £ti~iilgl!2 1 ChlaJ!!ll £.Q!:.!!scans !ls!ill.!l2.!.2 1 ostreidae Ostrea sandvicensis 1 Chamidae Cham~ sp. ---- • 2 tucinidae £!:~ bells 1 1 1 67 TABLE 10 (continued) Molluscs in benthic samples Station 1 1-1 1-2 1-3 S po r t e 11 ida e Ani so!!2.n!:l! l!!!.9J;! I.Sl!:.s 1 .• • A. lutea • • 1 Carditidae Tia£hi9a~~iY~ Q££i!s .. 1 Tellinidae Tellj·.I!i! rpQ.Yns 16 2 23 Veneridae f.2rigl.I.£!.a £s..ti£.Yls!:s • .. • 68 TABLE 11 Molluscs in benthic samples station 10 Numbers of individuals/25 1111 sample 10-1 10-2 10-3 Stomatellidae SlJ1S!J2tocpchm £.2ps:1:.!!!!.S 2 Turbinidae 1~t.2.tllI"s .!:ybIicin£ll 6 7 1. y:erI.!lca 6 Phasianellidae -_.Tricolia -- variabilis- -...... - ..... 6 Planacidae Plan~ill ID!111.!:~li§ 3 Bissoidae _-....--_Barleeia ._._calcarea ....IV •• __ 1 Me+e~ ~~pulq§a 10 1 11· l!ilW;~ 1 l1..wanavans 4 7 11. !ennen 2 jj§§2in~ J2Yl£~~!!2 2 !!. .!!!iltQZ2!lll 1 Vitricithna marmorata 8 ------, .. - ... -----..,.- £5~asbie!a ~~~~i 1 .§.£hw;artziella .9ha~!!i§ 1 Vermetidae 1 Cascidae £Aecu..!! ~.2im~!l,:tY1! 6 .. • Cerithidae ,Qi;t~ i!.E~.!!.2~ 3 • .. Triphoridae 7 2 4 Bulimidae Balcis brunnimaculata 1 vanikoridae!anI!Qr2actii:i--- 1 Cymatiidae 1 Columbellidae unidentified .. 1 • !uelicA ,!arig1}§ 1 Costellariidae yexi.!.!.!!l! sp. 1 2 ! .. §1\sXis 1 !. ~QJ!!Bi\l.!:l.l! 1 1- ilJ!!.lU! 2 Turridae ~inA.Ee! sp. 1 t;lav\1§ ]2QXe11i 1 unidentified 1 Conidae Conus abbreviatus • 1 .. Buecin idae~!i VIeolJ.i~!All .. q 1 PyramidellidaeFyrgy!i..!ll! .Q.Q4~§ 1 • .. Siphonariidae ]j.!liA.!l!i.S! .!:Alli.s!A 1 • • Areidae ~2r;12s1is sp. • .. 1 Pectinidae illll.I§ £orusean§ hawAiep,ill 1 Lucinidae 1 69 TABLE 12 Molluscs in benthic samples S·tation 14 Numbers of individuals/ 25 al sample 14-1 14-2 14-] Trochidae Troehus-intextus 3 1 .. ianiii.l euch~lii.9Iais 1 .. • Stomatel1idae ~ yna1?tocochlea .s:gncitllU\ 1 4 3 'furbinidae 1!H?to,!.h!ra .saU'!diga 5 5 6 !. I:gp,ric;j.nct,Sl 12 11 19 1. !eI;~.u.s:~ 2 • Phasiane11idae Tricolia variabilis· 30 34 33 Rissoidae !1e,elina.9iiiuIg~--·"'-- 3 1. J!ewa 3 5 6 I. wanawana 8 6 4 11 .. !~Inen .3 4 9 lissoin~am~igu~ 1 I_ l!1l1che11.1 2 3 I. miltozons 4 1 1 Sc.h wlrt zi~l:,la !"i:tiQ!.i 1 1 Vitricithna . msrmgf,£i'!:,e 9 13 9 farashie!a !!eetsi 3 4 1 Orbiteste1lidae or!'!i t,!sl.!J.la ~!gina·· 3 1 Oma109y·r1dae QJla1ogyr! j512pnica 1 Caecidae Caee!! sp. c.f .9..+,aR§ll.l 1 • £. S!eiBllntu,! 24 10 16 £. Ul29It lt" 2 £. °ll!uenu • 1 C. exile .. • 1 Dialidae iiala varu 7 12 11 ~i:thidi!!, R~'l?iI!.vlu 1 12 17 ~£s~i9Ai! sp. 1 • Cerithidae Bittium l?arcD 9 !!. i meepgens 19 1 15 m - --ee-titlIiY.lr-i!!terst&:!nlllu 1 Ceritbiopsidae ~S!~uli!.2I!!!it.l!l!!m 2 Citrithiopsi§ .u.s.a 1 Triphoridae 20 23· 30 Eulimidae j}alci§brunl!i!acg1at~·· 2 1 4 Vanikoridae !.inikoro·· illbli£.I!.1 • 1 • Hipponicidae .§i\bis· £.2nicl 1 • .. Marginel1idae Granul!§ii}lg.!i~ensis· 3 2 • .!olvariu sp.. • 1 cIsticu§ !Yn.l .. • 2 Columbellidae ID!plica·.!llii\ns· 1 ... • 70 TABLE 12 (continued) Molluscs in benthic samples Station 14 14-1 14--2 14-3 Conidae £Ql!.~ sp. 1 • • Thaididae Mgry.1:B sp. • 1 • ,Peotb als luu:.p.s co 2 • Pyramidellidae unidentified • 2 • Li£gYli~~ Q~ 1 Scapahandr idae ).cte~£in1! ~g!cen.2i.2. 1 Sipbonariidae!i}.!i.s.!t!.A lliillll 2 2 Aplysiidae 1 2 Bivalia unidentified • 1 Arcidae Bjir!!.i!1is sp.. 1 Pectinidae £lli..m.I§ corusc TABLE 13 Molluscs in benthic samples Station 16 Numbers of individualsl 25 ml sample 16-1 16-2 16-3 Scissurellidae .§~iss'y:{e :tJa · l?§eu,goeg.~stori-s 1 • • Fissurellidae .Qiodora~!l.l22~l.!i .3 .. • Trochidae liyche).'!U?~J!!m!!§ 3 • • Troe.h'!~ ' inte,;xtus 7 .. • G ibbula marmorea 1 • • Dinii~ieueh.elj,f oill.§ 3 2 2 Turbinidae Leptot.blra sp. .- 1 • L. candida 9 2 2 i:.iibriein9J;q. 1 3 1 ,1- ,!J~rEuea " 2 " • Phasianellidae ~rieolia variabilis 8 1 2 Rissoidael1'§!E~)'lqa~wa --_. 8 3 1 11. n.!!awall~ 24 22 1 iisspi llf.\!l.2.bs!i!15 • 1 " ,E. !;urriculs " 7 .. 2 .y itri.eithna · ,!~.J;!.Q.{.sll 46 6 5 Parashielabeetsi 6 • 3 ZeMna .tride.ntata 1 • .- IsseI1a hiloense~ • 1 • orbitestelIId'aeorbIt~§ii!.!5! ,Iegipg, 7 3 5 Omaloqyridae .2l!!!.!g9.!!l!japgj!iga 5 • Vermetidae ,. 1 ;0 Caeeidae ~e£1J..!!sepim~.!! 7 4 2 Dialidae piala Isri£l: 57 56 18 .Q..§Qpeg~o!:y.m • 2 " ~erithidj.y R~~..I2al:!.Y!.Y.m 5 2 1 Cerithidae li!!!ilu!l sp. 1 ]. paJ;P!!!! 10 • !! ·al2!:.!!.!! 65 • 7 Tri·ph oridae- · ··· --_ .. - ·23 3 · 3 Eulimidae Bal£i.§ ~.!.2 1 • • ]u1ims ., e~~§~i 1 " • Strombidae .§tro!bus sp. juv 1 '. " calyptridae £1£eeidula i!£.Y!~ 3 1 2 Marginellidae Q..ran.!!l~ §,S.!!g.~i£~~ 7 2 2 Qll.!!uli.!!2 "~i!:I~ • 1 • Turridae llitro!~ sp. 2 • " M. metula 1 1 • iie~iih~ ' !!.i£h~ 1 • ,. pyramidel1idae Qd9§!.2.!!ia ·· sp. 1 • • 72 TABLE 13 (continued) Molluscs in benthic samples Station 16 16-1 16-2 16--3 Q.dos;t.gmU n.isrnsiel.1a • 2 • Q. gu!19£i 1 .. 8inemo.l i!uli£A 1 • Turboni!!! !iral~ 1 • 1. thaal!Jl.li • 1 ,fyrqul,.:iJlsS!ode§ 3 2 1.31&;n21s l.flct~o1:i .. 1 Atyidae Ham.ingea CUEts 1 • !!iniat1s ,gs;otifer 1 A.U.2 §elistr:iatD 1 • .. Scaphrandridae Ag~eog.i.n.lllA.!n~nsi§ 1 1 Aplysiidae .. 1 .. Arcidae Barl>!·tj&·sp•.... 12 3 1 unidentified .. 3 • Pectinidae Chlam.,!s corqsca,Ds ... hawaiensis 1 .. L'uCI'iiidaeunidentified -- .. 2 .. &tenA ;bella 3 .. Lasaeidae .!.!sobornia barts£!li 1 iadobgrnia hIya!! 1 • • Te11inidaeunidentified .. 1 • 'fe 1: 1iU nhust§: .. 9 .. Semelidae · . §i.le1angl1!11§ c£ebrimacyla!n 3 • 11 73 TABLE 14 Kolluscs in benthic samples Station 21 Numbers of individuals/ 25 ml sample 21-1 21-2 21-3 Fissurellidae ~margip\4.1s sp.. 1 • .. E. dilecta 1 • • i!i;idora-~~!!iUu ,. 1 .. Trochidae Gibbula marmorea 1 1 1 ----,TiOC'huS intextus ... -- 4 4 1 stomatellidaa a.IllAEtocgcbl§S ~onqi.nnA 11 7 Skeneidae102.bg~2chli.a§ .!!!i.n.l:!ll§!1~ .. 1 Tur:binidaeLeptotb.II! ~Ang!,gl! 12 1 1 1. IY~!ic~n£!s 50 19 9 1. IitlIuca 12 5 Phasianellidae Tt;:i:~oliA U!!sJ2i,lis 39 30 9 Rissoidae 11Si!::ili~ sp. 2 11· 5l.Ian!lq§s 1 11· !.t~U 2 6 7 11. .!inawap,!! 7 9 8 11· !sU!.n~.I! 5 10 6 .Ei§§9inA ambigY9 3 3 4 ,E. 21' 1~hel1a 2 1! • .!!!il toZ; Q!.U! 3 7 4 11· !l1!Ii~Mla 1 1 .§£~.!.Q!;!~i~!li\ !I!!j.~~~ 3 3 1 ~" SU:a~il!§ t Vi!rici~hnp. miU.!!U2IsI:s 3 6 11 .fA rSls;hisall .!UU~ :t§! 2 1 6 !.§~elii .kiloen~~ 1 • Rastodentidae lastode.n§ sp. 17 '" Orbitestel1idae Q!!li.t~§t§!J..!i !~gina 2 Varmetidae 2 Caecidae £i!2~.!!!·§~1?j.~$Intu!!! 9 20 17 c. vertebrale 5 • 1 $:treblo~Ii§- §uQanlPJ.!~tu.!!!· .. 1 • Dialidae 11isl.s..!..QI!,S • • 3 ]. §£.P~!llorum .. 1 C~~!1Aidi~ ~~~~~£!~!~ 3 11 3 Cerithidae !!illW sp. 4 • ]. Rarcum 41 22 8 .f!. .u!l}l.!!.!!! 10 5 ·to !!.. im2€.ngen§ 18 8 Cerithiuminterstriatum .. 1 1 ~~SIQii£:Yi-- -- 1 .. 3 74 TABLE 14 (continued) Molluscs in benthic samples Station 21 21-1 21-2 21-3 Cerithidae f:eri!.hi!ll'! ·§geny.! .. 1 'l'ripboridae 23 28 16 Cerithiopsidae .h,grit.qiol!si,§ sp. • .. 2 J9cul~t~~ ~~~ 1 • .. Eulimidae l!S\lc~ s1'. 3 • .. ~~hi1!e.!!.!lli sp. '" 1 • ID!~ .eea~~i 1 • Buccinidae EngiDs·ID.g.§i§£i.s 1 • .. Columbellidae ~qelica var!s!!.§ 2 1 • ll.!.Q~! l.lr i !}s 1 '" .. Marginellidae Granulasandwicensis 3 2 • §!i:gnulina.!ii!=~i- • 2 Costellaridae l@xlilum s~ 1 • nUs! os:i-lls 3 • .. 'l'urridae £~rinsl:!~x YDutj.§§i.ms: ·· 4 • 1 Keqllis sp • . it 1 • 1£. melanoxyt!1.m .. 1 .. ,tJitr5!l.l!.!.!!.s .metlllg. • 1 2 !a- ni .. 2 • ~. alphonsian.s '" 1 pyramidellidae .1'yrbo»illi sp. 3 • .. Aplysiidae • 1 1 S iphonariidae!JJ.lia mis ~giil!1\ 1 3 1!i.eboP51riSl sp. 1 ~. lU2~'p]iili§ 2 Arcidae llarbn!.s sp. 1 2 1 Pect i nl d·ae£!!l.a!!tI§ 1 r re g~!yi.2 1 c. coruscans hawaiensis 1 Lucinidae Ctena bEd:ra- ---- 1 1 Telli nidae-- _. -. 1 Semel idae 1ono~ ~~~ili~§· · • '" 1 75 TABLE 15 Animals in benthic samples Station 1 Numbers of individuals; 2 litre sand sample 1-1 1-2 1-3 Nematoda 28 24 99 Sipuncula 1 2 1 Polychaeta Polynoidae 2 Amphinomidae .1inophe!:us sp. .. • 40 Pbyllodocidae pbyllodocid sp. 2 • 3 Hesionidae ? J?2q?.t;~~ J2J!9s!:!dHH3i.=? .. 5 3 Syllidae 41 66* 119* Nereidae nereid epitoke 1 Glyceridae Gly;£§.~ g§se!f!ls • 1 1 Eunicidae1Isid-i~ £.Qj.lari§ .. 1 .. .Nemsto!le~ .. .1Uli£Qni~ 36 40 87 Eunice vittata .• 1 24 Dorvilleidae ~~,!Jtlei~SDgQls~ .,. 1 Spionidae !.Q.!li~ .2!I£~..eh~.1& 2 ,. 23 spionid sp .3 .. • 11 Cirratulidae Dode£~.s!:i.s W.!l! • 1 £i,!;,rifQI.!ia sp. 56 98 112 Opbeliidaelrmandia illua~.ili.s 1 17 Capiteilidae S;;aP.!1211l! £.s211atft • 5 2 ~aSlbr~n£hu~ SPa 2 ~Qi2.!!!iUr!.Y§ sp,. 3 capitellid sp. 2 10 38 30 Sabellidae 1BIBiscom~§ sp. .. .. 1 ~~l!l.2~~s !~~~ • • 1 sabellid sp. 1 1 Serpulidae ,!!IQroide§ 12!:A£9..Is£.s:plli 1 1 ~~Ilt!!l.sy~u:;micllill§ 1 Oligocbaeta 1 ostracoda 2 .. .. Copepoda Harpacticoida- . 2 - 7 27 1~J2to£~~lis 9.Y~iA .. 6 2 fars~!hu~a ,g~~gA~~gi 1 1 32 Amphipoda unidentif.ied • • 1 tls.~,g sp .. • 1 ]la§'!9l?.!!.2 sp. 1 1 • 1l'.1!.Y.slll! s!!j.kaj, .. • 1 J.eu£otho~ sp. 1 .. • Al ehe..Y§ sp. .. • 1 16 Table 15 (continued) Animals in benthic samples station 1 1-1 1-2 1-3 Number of species 20 19 30 Number of individuals 297 508 890 Diversity H' 1*95 1 .. 99 2 .. 33 Evenness J .. 65 .68 .69 * plus 3 juveniles in 1-2 and 5 juveniles in 1-3 77 TABLE 16 Animals in benthic samples Station 10. Numbers of individuals/2 litre sand sample 10-1 10-2 10-3 Nematoda 3 4 Platyhelminthes polycladida 8 9 14 Sipuncula 4 6 6 Po1ychaeta Palymridae PalmI!.\! sp_ 1 Amphinomidae~j.no.Eher.!!2 sp. 1 Pisionidae f!§i~sp. 8 7 2 Fisionidaas indica 5 Phyllodocidae PhxIiid~ce-!~bJf.2ls • 10 phyllodocid Spa 2 2 1 Sy11idae 2 1 26 Eunicidae 1IsAdic~ £.Qjl.!Ii§ 1 Nematoperei§ P.PA£.Q!1li§. 6 Onuphidae J!othris !!.212i!!.f!A£!tAsis 13 3 68 Arabellidae Arabel!s illi£21Q,£ 1 Dorvilleidae l!g£Iil;l~5! .s!!9QIgn.f! • 1 Spionidaa ,Rg!.ZS9'!;;1l sp. 2 Aoniqe,§ oXI£~Il!!s1.s 1 Cirratulida€! 12.Q5!~£aQ§.!:ia !.~di 1 C.haetopteridae .fl:UJ.locha~tol?j;ef..!!§ nrrilli 1 Cossuridae £ossuil sp. ·1 • Capitellidae capitellid Spa 2 • • 5 Sabellidae labriciA Spa 1 Archiarrnelida 1 • copepoda Harpacticoida 1 • Isopoda ,.earantbu£,.a .Q.2~e!gAA!.li 2 4 amphipoda ~usirpide.§ .die;tp.!!u 1 M~ Spa 2 17 ElasmoEu~ Spa 10 16 uniden-tified 2 10 !liepa Ei!vif.lli • 1 • Crab megalops • • 2 ?LeE!cdiusexa.t;e.!ys 1 £r.!stallodytes £2Qkei 1 Number of species 11 14 25 Number of individuals 47 48 204 Diversity H' 1.94 2.15 2.34 Evenness J .81 .82 .73 78 TABLE 17 Animals in benthic samples station 14 lumbers of individuals; 2 litre sand sample 14- 1 14-2 14-3 Nematoda 35 673 383 SipunC'ula 2 • .. Polychaeta Pisionidae Pis.i£U!Jg sp .. 2 .. 1 .e!fliopid.e.n.2 .i1!giz,S! 3 .. .. Phyllodocidae J?!!.X1lod,Q£Jg .t.!l!!.i&.9l&t .. 1 .. Syllidae Mereidae Nareis corallina 1 --- ...... _- Onuphidae!oUIU b21QR!:IDl~!1i-a~ 8 1 1 Dorvilleidae Qor!!lles ?.sJ!'s2l.s1!s LJ 5 1 S pion idae!\pnides £t!:l£Jg.E1!sla 1 6 3 uniden tified spionid 1 .. Opheliidae ArlR.~n~:.j.~ iJ!termS!gia 3 9 12 .fUI.2.E!Ehs.!!t.!H? .e.iZt.J!!l 4 1 • Opb.!!.!.!!! sp. .. • 2 Ostracoda 1 1 • Copepoda Barpacticoida 16 15 1~Q£h~~~~gybi! 3 8 5 .fy!'!!hu~9-·ost~rga.f1I4.i 2 .. • Amphipoda unidentified Gammaridae 1 .. .. Mae!:! SPa 3 1 3 J?:!Ssmo.E.1!§ sp .. 3 1 4 unidentified family 1 .. proze§§i! sp. • • 2 Caridean Spa 1 " 1 • Xanthid Spa 2 1 .. ? ~.E!odiu2 ~!:.s!~ 1 • • Number·-of -species 21 Ht- 14 Number of individuals 102 1262 482 Diversity H' 2. 31 1. 09 o. 91 Evenness J .. 76 .38 .. 34 79 TABLE 18 Animals in benthic samples Station 16 !lumbers of individuals; 2 litre sand sample 16-1 16-2 16-] Nematoda 14 31 86 Sipuncula " 2 1 ~.!l2.LQl!i§£2smBloEpi:ta 4 8 Polycbaeta Phyllodocidae flfyJ:l.9.d,Qg .tYB.igo!a . 2 • Eunicidae l!~g!Qner~i§ .Y.!!i£,g!l!~ 1 • • Spionidae !gniilloxyqttEAsl& 4 4 2 ! l!Inchospio .. sp. • 1 Cirratulidae ]9g,!cecaria!,g~lgi • 1 17 Chaetopteridae ~J2i.Q£~.2R!~£.!!§.!itrari.!!§ 1 3 OrbiniidaelIaiMW la~vig,g,t:s 1 5 1 Opbeliidae JI!.An9!A in:t~!'!\jdia 10 13 8 .Q1!i!~lin€! sp. 2 2 Capitellidae £€!Ri!ell9. £l!e:j.t!!!.s; 1 12UIRran£w sp. 2 1!.Q!9.!!la§,.!t§ sp .. 1 capitellid SPa 2 4 3 capitellid sp. 3 • 3 .• ostracoda .. 6 11 Copepoda Harpacticoida " 1 " E 1,!S .!.2.ID!§ sp. 1 Caridean Spa 1 2 1 2 Caridean Spa 2 " • 1 Crab megalops 1 ? 1&2 t g,giy§ ~ln£iU.!!§ .. • 1 Holot huroida " • 1 Number of species 11 18 13 .. N1l1l'lber of individuals 44 88 140 Diversity Hf 1.81 2.17 1.32 Evenness J .. 78 .75 .52 80 TABLE 19 Animals in benthic samples Station 21 Numbers of individuals/ 2 litre sand sample 21-1 21-2 21-3 Cerianthidae 1 • Nematoda 149 126 183 Sipuncula 2 • .2 Polychaeta Amphinomia.ae 1i!lo.eh~IU.2 sp. 6 21 • PhyllodocidaePhyllog~ ~£.2!2 7 1 • Syllidae 14 8 22 Eunicidae ------Nematonereisunicornis-_. --- 1 Onuphidae !othrig. holoh.I2~£hiA!i\ 1 • Dorvilleidae yor.!ilJ&.s 121HIP!slUt. 6 8 27 Spionidaa Aonig~2 qXY~!a.2!!~1.s. .. 1 unidentified spionid 2 Cirratulidae Dodeceearialaddi 8 8 £it!:J.-fg!ili~ICin~!!·· • ;0 1 Chaetopteridae Sl:i2.£haetoj!!~!!!§ ,!ills1=lY§ 1 • Paraonidae1.f.~!!Q!l!'§ sp. 2 o pbeliidae AnSJ!lli i!!.!st~!!I~!li& 2 7 .f2!I9.Eth aJ:J!l!§ :e.!£!.!!§ 2 2 1 Qphe],iD,!J; s p .. 7 • 1 Capitel1idae .Qll~.!bU!nc»!l§ sp. .. 1 capitellid sp. 2 52 14 78 ostracoda 1 ;0 Copepoda Harpacticoida 17 Copepoda Cyclopoida 1 • • 12.EfRc.Mlli~~!211 4 8 lilssmopus sp. .. • 2 ?~Ptog!~2 ~~~ 1 NUiiiber of species 22 9 16 Number of individuals 289 189 346 Diversity H' 1.76 1.21 1.48 Evenness J .57 .55 .53 BIBLIOGRAPHY Al=Hussaini A.H. 1946. The anatomy and histology of the alimentary tract of the bottom-feeder Mulloides .u£ifl's.!ti (Forsk.) J.Morph. Philad. -78: 121::153 ------1947. The feeding habits and the morphology of the alimenta.ry tract of some teleosts living in the neighbourhood oftha Marine Biological Station, Ghardaqa, Red Sea. Publ. Mar. BioI. Station Ghardaqa (Red Sea) No. 5 Bailey-Brock J.H. 1976. Habitats of tubicolous polychaetes from the Da waiian Islands and Johnston Atoll. Pac.. Sci. 30 (1):69-81 ------1979. Sediment trapping by chaetopterid polychaetes on an Hawaiian fring inqreef.. J.. Mar. Res. 31 (4) :: 643-656 ------1980. The community associated with ]2ipJ!,SUA ~!ckar!i, a sand-fixing polychaete, in Hawaii. Am.Zool. 20(4):929 Baldwin W.. J. 1972. A new genus and new species of Hawaiian Gobiid fish. Pac. Sci. 26:125-128 BannerA.H. and J.E.Randall. 1952. preliminary report on a marine biology study of onotoa Atoll, Gilbert Islands. Pac. Sci. Bd. Nat. Research Council Bauer C.F.. 1981. The food and feeding habits of two species of goatfishes (Mullidae) ofPuertoRico.M. S. theSis. University of Puerto Rico, Mayaquez, Puerto Rico. Birkeland C. and s. Neudecker. 1981. Foraging behavior of two Caribbean Chaetodontids:£,Pset,QQ.Ql; c:aEi.§!.!~ and £. ac.Yl§:~tu§ copelia 1981(1):169-118 B.renchleyG.A~ 1976. Predator detection and avoidance: Ornamentation of tube-caps of1!i<2R~!'[A species (Polychaet a: Onllphidae).. Mar. BioI. 38: 179-188 Brock B.E. and J. H. Brock. 1917. A method for quantita ti vely assessing the inf aunal community in coral rock. Limn. and Ocean. 22(5):948-951 Chesson J.. 1918.. Measuring preference in selective predation. Ecology 59(2) :211-215 - 81 - 82 Cock fil.J. W. 1918. Tbeassessment of p.refere.Dce. ..1. An. Ecol. 41:805-816 Colwell B.R .. and D • .1. Futuyma. 1971.. On the measurement of nicbe breadth and overlap. Ecology 52:567-516 Dollar s • ..1. 1978. Guide to research logistics in the Northwest Hawaiian Islands.. working Paper No. 33. Sea Grant College Program.. UraiV'. of Hawaii Edmondson C. H.. 1946. Reef and shore fauna of Hawaii. Bishop Museum, Honolulu. 381 pp ------1962. Xanthidae of Hawaii. Bernice P.Sishop Museum Occ. Papers XXII(13):215-309 Fauchald K. and P.A. Jumars. 1979. The diet of wo.rms: a study of polychaete feeding guilds. Oceanogr. Mar. BioI. Ann. Bev. 17:193-284 Fowler H.i. 1933. Contributions to the biology of the Philippine Archipelago.. The fishes of the families Banjosidae... " ... Mullidae. u.S. Nat. Plus. Bull.. 100 (12). 465 pp Feinsinger P., E.E. Spears and B. W. Poole. 1981. A simple measure of niche breadth. Ecol. 62(1):27-32 Gabriel w. t. 1978. Statistics of selectivity. i.n Fish Food Habits Studies.Proc. 2nd Paci fie North west Tech. Workshop. S.J. Lipovsky and C.l. Simenstad (edit): 62-66. Unlv.of Wash. Sea GrantPubl. WSG-WO·-79-1 Gibbs P.E. 1975. Survey of the macrofauna inhabiting lagoon deposits on Aitutaki, Cook Islands. Atoll Bes. Bull. 190: 123-131 ------1978. Macrofauna oftha intertidal sand .flats on low wooded islands, northern Great Barrier Reef. Pbil. Trans. R. Soc. tond. B 284:81-97 .. Gi-bos P. E.,. H. G.Vevers, and D .. R .-st-oddar-t. 1975.-Marine fauna of the Cook Islands: check-list of species collected during the Cook Bicentenary Expedition in 1969. Atoll Res. Bull. 190:133-148 Gosline iiI.A. and V.E.. Brock. 1960.. Handbook of Hawaiian fishes. Univ. Press of Hawaii. 372 pp 83 Harmelin-Vivien M.L. 1979. Ichtyofaune des recifs coralliens de Tulear (Madagascar): Ecologie et relations t.rophiques. D.Sc. Thesis. LtlUnive.rsi te d t Aix-Marseille 11 Harrison C.S .. and T. S. Hida.1980. The status of seabird research int.ueNortuwest Hawaiian Islands In Proc. Symp. on the status of resource investigations in the HWHI ... Ed. R.i.Grigg andR.~. Pfund.,' Sea Grant Misc. Rpt. UNIHI-SEAGBAHT-MR-80-04 Hiatt B. W. and D. W.. Strasbu.rg. 1960. Ecological relationships of the fish fauna on coral reefs of the Marshall Islands. Ecol. Mono. 30(1):67-127 Hobson E.S. 1968. Predatory behavior of some shore fishes in the Gulf of California. u.s. Fishiidllife Serve ,es. :apt. 73:1-92 ------1974. Feeding relationships of teleostean fishes on coral reefs in lona, Hawaii. u.s. Fish. Bull. 72 (4) :915-1()31 Holland K.H. 1976.. A behavioral and electrophysiolo Hulberg t.W •.. and J.S. Oliver.. 1979.. Prey availability and the diets o.f two cooccurring fla tfish. In C. A. Simenstad and S.J. Lipovsky (edit) Fish food habit studies.. Proc. 2nd Pacific No.rthwest Tech. Workshop 1978. Univ •.. Wash. Press, Seat.tle. Ivlev V. S. 1961. .Experimental ecology of the feeding of fishes. Yale Univ.press.. New Haven. 302 pp Jacobs J. 1914. Quantitative measurements of .food selection. A modification of the Forage Ratio and rvlev's Electivity Index. Oecoloqia 14:413-411 KluegelE. 1921. The food of Hawaiian food fishes. .M.s. - TbcesisUniv .;oflta11 a-i~i Kahn A.J. and K.C. Lloyd. 1973. 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