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Report: Faunals

Report on Zooarchaeological Remains from the Seven Site,
Nikumaroro, Phoenix Islands

July 5, 2008

Sharyn Jones
Department of Anthropology
University of Alabama at Birmingham
Heritage Hall, Rm. # 315
Birmingham, AL 35294-3350
Email: sharynj@uab.edu


All fauna from the 2007 Seven Site excavations was identified using comparative collections held in the Zooarchaeology Laboratory at the University of Alabama at Birmingham. The comparative collection includes hundreds of skeletons of marine fishes from the tropical Pacific Islands, including materials from the geographic areas of Micronesia, Polynesia, and Fiji. Multiple individuals of various size classes of the most common species have facilitated identification and the development of secondary data such as biomass and size classes. The collection contains numerous individuals in the following families: Scaridae, Labridae, Serranidae, Carangidae, Acanthuridae, Scombridae, Lutjanidae, Mullidae, Siganidae, and Holocentridae.

Zooarchaeological methods follow techniques developed by Reitz and Wing (1999) and are explained elsewhere in detail (see O’Day 2001). All efforts were made to identify faunal specimens to the lowest taxonomic level possible, that is, with as much specificity as possible. Fish taxonomy followed Myers (1991) and Froese and Pauly (2004).

All faunal material was counted and weighed and modifications such as cut marks or burning were recorded. The number of identified specimens (NISP) is the basic specimen count used. Minimum number of individuals (MNI) were determined by paired elements and estimated age or size-class for vertebrates. Following Reitz and Wing (1999:194), MNI was defined as the smallest number of individuals that is necessary to account for all skeletal specimens of a given species within the assemblage. Initially, when I estimated the MNI, each provenience (unit or feature) was considered separately. This is a non-conservative method of estimation that results in more MNI for the entire Seven Site faunal assemblage. For comparative purposes I also estimated the MNI using the more conservative method of deriving MNI from the combined taxa identified from all the features/units. The conservative estimate is compared to the non-conservative estimate in Appendix A. The non-conservative estimate, total MNI of 74, is significantly larger than the conservative estimate of 46, but I believe that the non-conservative estimate is a more accurate representation of the actual foods that were consumed in discrete cooking and eating incidents, as evident in each of the features (M-2, 2D, 3D, BR-1, WR-1, SL-1, etc.).

Estimating Fish Size

The Seven Site assemblage contained a total of 570 fish vertebrae. A sample of the anterior widths of the vertebral centra were measured as a proxy for fish size, following the assumption that the fish vertebrae (identified and unidentified) provide a representative cross-section of the species in the assemblage (O’Day 2001; Wing 1998). The vertebral centra width data will be used to estimate the average body size of fish in the assemblage.

Estimates of Dietary Contribution

Calculated sample biomass was used to estimate the relative dietary contribution from the skeletal weight of archaeological specimens.  These calculations provide information on the quantity of meat potentially supplied by an animal based on allometric principles that an animal’s body mass, skeletal mass, and skeletal dimensions change in proportion with body size increases (Reitz et al. 1987).  Biomass estimates provide information that cannot be ascertained from specimen weights alone, such as those presented in Tables 2-4. 

The following allometric equation was applied to data from the Seven Site assemblages in order to describe the relationship between body weight and skeletal weight, estimating the amount of meat or soft tissue related to the archaeological materials:

Y = aXb   or  log10 Y= a + b (log10X)  where:
Y = estimated sample biomass (kg) contributed by the archaeological specimen for a taxon
X = specimen weight (kg) of the archaeological specimen for a taxon
a = the Y-intercept of the linear regression line
b = slope of the regression line

Sample biomass, or soft tissue weight, was predicted for each identified faunal group (i.e. fishes, birds, and turtles) using specimen weight for X, in the above allometric formula.  The allometric constants, a and b, were obtained from Reitz and Wing (1999:72) who originally derived the constants from a large set of reference specimens (Florida Museum of Natural History, University of Florida) with known whole body weights and dimensions of the skeletal elements. 

Niche Width or Diversity Measures

In this study I applied the Shannon-Wiener Measure of niche breadth or diversity to the zooarchaeological data from the Seven Site in order to measure the degree of specialization found in the assemblage.  The measure quantitatively characterizes the variety of animals used within an assemblage and the relative importance of the species present.  Niche breadth was measured by observing the distribution of individual organisms within a set of resource states.  The formula used is (following Krebs 1989:376):

H′ = - ∑(pi)(loge pi)

where H′ is the information content of the sample and pi is the relative abundance of individuals or resources for each taxa in the collection. For bone, niche breadth was calculated based on MNI measures. MNI is the preferable measure for obtaining niche breadth because it places diverse organisms, with uneven numbers of elements per individual, on a more uniform basis.

Since this diversity measure ranges from 0 to ∞, it can be standardized on a scale from 0-1 by using an evenness or equitability measure, V′. Equitability indicates the evenness with which species, or animal resources, in a given assemblage are used. The equitability formula used in the analysis is (following Reitz and Wing 1999):

V′ = H′/ loge S

where H′ is the Shannon-Wiener function and S is the number of taxa for which MNI or NISP was estimated. Both diversity and equitability indices were calculated based on MNI for vertebrate remains, including: turtle, shark, and bony fish. 


The 2007 Seven Site faunal assemblage contained a total of 1401 bones, including 1168 fishes (shark and boney fishes), 78 fragments of turtle bone, 155 bird bones, and one highly fragmentary bone of a medium-sized mammal (likely a dog or small-medium sized pig).  The vast majority (>90%) of the faunal material was burned and highly fragmentary. 

Table 1. Summary of Faunal Identifications in taxonomic order from the 2007 excavations of the Seven Site, Nikumaroro; this includes the features: SL-2, SL-3, and WR-1.

Mass (g)
% Mass
biomass (g)
% Biomass
Cheloniidae 78 5.6 7 9.5 85 30.1 1330.47 29.5
Carcharhinidae 3 0.2 1 1.4 1.2 0.4 34.88 0.8
Muraenidae 2 0.1 1 1.4 0.1 0.0 4.90 0.1
Belonidae 5 0.4 1 1.4 0.41 0.1 14.93 0.3
Holocentrinae 24 1.7 1 1.4 1.9 0.7 50.14 1.1
Myripristis sp. 3 0.2 1 1.4 0.2 0.1 8.47 0.2
Serranidae 34 2.4 3 4.1 5.4 1.9 111.66 2.5
Cephalopholis sp. 12 0.9 3 4.1 2.7 1.0 62.81 1.4
Epinephelus merra 3 0.2 1 1.4 0.11 0.0 4.41 0.1
Epinephelus sp. 30 2.1 3 4.1 6.71 2.4 133.71 3.0
Plectropomus sp. 3 0.2 3 4.1 0.2 0.1 7.24 0.2
Carangidae 41 2.9 4 5.4 5.7 2.0 116.78 2.6
Caranx sp. 65 4.6 8 10.8 28.64 10.1 445.95 9.9
Pseudocaranx dentex 1 0.1 1 1.4 0.6 0.2 18.02 0.4
Lutjanidae 7 0.5 1 1.4 0.8 0.3 22.89 0.5
Lutjanus sp. 1 0.1 1 1.4 0.1 0.0 4.07 0.1
Caesio sp. 1 0.1 1 1.4 0.01 0.0 0.60 0.0
Lethrinindae 1 0.1 1 1.4 0.1 0.0 4.07 0.1
Mullidae 1 0.1 1 1.4 0.1 0.0 4.07 0.1
Parupeneus sp. 10 0.7 2 2.7 0.9 0.3 25.24 0.6
Labridae 1 0.1 1 1.4 0.7 0.2 20.48 0.5
Scaridae 8 0.6 4 5.4 2.1 0.7 50.98 1.1
Scarus sp. 5 0.4 3 4.1 2 0.7 48.96 1.1
Acanthuridae 12 0.9 3 4.1 2.1 0.7 50.98 1.1
Naso sp. 11 0.8 3 4.1 1.4 0.5 36.42 0.8
Siganus sp. 1 0.1 1 1.4 0.01 0.0 0.60 0.0
Balistidae 7 0.5 3 4.1 2.7 1.0 62.81 1.4
Scombridae 22 1.6 3 4.1 4.8 1.7 101.26 2.2
Perciformes 62 4.4 1 1.4 8.5 3.0 162.71 3.6
Unidentified fish 792 56.5 7 9.5 90.2 31.9 1155.64 25.6
Bird 155 11.1 0 0.0 27.1 9.6 411.15 9.1
TOTAL 1401 100.0 74 100.0 282.49 100.0 4507.00 100.0

The Features

Each unit or feature was analyzed separately and then amalgamated to estimate the total assemblage overall secondary data, such as biomass and diversity and equitability (Table 1).  Summaries of the identified fauna from each feature are presented in the tables below (Table 2-4).1 A list of common names for the identified species is provided in Appendix B.

Table 2. Unit/Feature SL-2 Faunal Summary.

The material from SL-2 was dominated by unidentified fish bone fragments (Table 2). The classification, “unidentified fish,” in all of the units refers to bone that was primarily composed of fragments of elements, or of elements that are not identifiable to family, genus, or species (for example, spines and rays, which are so copious in fish skeletons).2 The unidentified fish was often broken and highly fragmentary, in addition to being burned, therefore making identification of some of the material impossible.

All of the bone in this unit was burned or it had ash or charcoal on it, indicating that it was excavated from a fire feature. The fishes represented by the bone in SL-2 include, in decreasing order of abundance: Carangids (Jacks), Acanthurids (Tangs), Balistids (Triggerfish), and Scarids (Parrotfish). Bird bones and fragments of turtle bone were also identified from SL-2. The turtle remains included fragments of Cheloniid (Sea Turtle)3 carapace and/or plastron from two individuals. One of the turtles is a very young individual (perhaps recently hatched) and the second was also a sub-adult individual, but appears to be older than the first. Nesting turtles are notoriously easy to capture, as are their offspring.
Taxa Count weight (g) MNI
Unidentified fish 38 8.7 2
Acanthuridae 1 0.2 1
Balistidae 2 2 1
Caranx sp. 6 10.84 2
Naso sp. 8 1.1 1
Scaridae 1 1 1
Bird 1 0.1 1
Cheloniidae 6 4.3 2
Total 63 28.24 11
Table 3. Unit/Feature SL-3 Faunal Summary.  

Taxa Count weight (g) MNI
Acanthuridae 4 1.1 1
Carangidae 9 2.5 3
Caranx sp. 12 3.4 2
Carcharhinidae 3 1.2 1
Mullidae 1 0.1 1
Muraenidae 2 0.1 1
Pseudocaranx dentex 1 0.6 1
Scaridae 2 0.4 2
Serranidae 3 0.2 2
UID fish 74 8.4 2
Total 111 18 16

The fauna from SL-3 was slightly more abundant than that from SL-2 (Table 3). The fauna from SL-3 is entirely fish bone. Carangids (Caranx sp., Pseudocaranx dentex, Carangidae) were the most frequently identified fishes (MNI = 6); Serranids and Scarids were the second most common taxa. This feature contained two vertebrae identified as Moray eel (Muraenidae) and three vertebrae of a small reef shark (Carcharhinidae). These identifications are notable since these taxa do not occur in the other features. Both moray eels and small reef sharks could have been collected in the lagoon or on the seaward edge of the reef.

The bones in SL-3 were the least burned of the three features examined. Many of the bones exhibited evidence of burning on an open fire or they came from a fire feature (covered in ash or charcoal), but were not burned. The shark vertebrae appear to have weathered on the surface of the site, resulting in a pitted and worn exterior.
Table 4. Unit/Feature WR-1.  
Taxa Count weight (g) MNI
Acanthuridae 7 0.8 1
Balistidae 5 0.7 2
Belonidae 5 0.41 1
Bird 154 27 2
Caesio sp. 1 0.01 1
Carangidae 32 3.2 1
Caranx sp. 47 14.4 4
Cephalopholis sp. 12 2.7 3
Epinephelinae 10 1.5 0
Epinephelus merra 3 0.11 1
Epinephelus sp. 30 6.71 3
Holocentrinae 24 1.9 1
Labridae 1 0.7 1
Lethrinidae 1 0.1 1
Lutjanidae 7 0.8 1
Lutjanus sp. 1 0.1 1
Myrpristis sp. 3 0.2 1
Naso sp. 3 0.3 2
Parupeneus sp. 10 0.9 2
Perciformes 62 8.5 1
Plectropomus sp. 3 0.2 3
Scaridae 5 0.7 1
Scarus sp. 5 2 3
Scombridae 22 4.8 3
Serranidae 31 5.2 1
Siganus sp. 1 0.01 1
UID fish 680 73.1 3
Cheloniidae 72 80.7 1
Medium mammal 1 1.7 1
Total 1238 239.45 47

WR-1 contained the vast majority of bones by all measures (NISP, MNI, and weight), and the assemblage is more diverse than that from the other features (including the 2001-analyzed material). Bird bone was especially abundant in this feature, contributing 154 NISP and 27 grams to the assemblage (Table 4). I made a gross estimate of the number of birds (MNI) represented by the avian bone, based on the size of the elements present: there are at least two individuals represented, but likely more. These bird bones should be sent to a specialist for identification.

Turtle bone was identified from WR-1. Like the turtle bone from SL-2, the bones are highly fragmentary, burned, and broken up (a possible indicator that the turtle was cooked in its shell). Unlike the SL-2 turtle, the WR-1 turtle represents an adult individual and a third MNI overall, for the Seven Site.

A single mammal bone was recovered from the surface of WR-1. I was unable to identify this bone to species, but this vertebral spine fragment comes from an animal the size of a small or medium bodied pig or a dog (“medium mammal”). This is the only mammal bone present in the 2007 excavation material faunal assemblage.

A variety of reef fishes are represented in the WR-1 fish fauna (Plectropomus, Epinephelinae, Epinephelus spp. and Cephalopholus). A total of 11 MNI are attributed to groupers. Small-bodied groupers are commonly found on inshore reefs and in lagoons. The second most common taxa are Carangids (Jacks), represented by five MNI, including Caranx sp. and the family level identification, Carangidae. Acanturids (Tangs), Acanthrudidae and Naso sp., were represented by 10 elements and three individuals. Holocentrids (Squirrelfish and Soldierfish), including the sub-family Holocentrinae and the genus Myrpristis, were also frequently identified form WR-1 (NISP = 27; MNI = 2). Ten elements, mostly vertebrae representing two Parupeneus sp. (Goatfish) individuals were also identified.& Two Balistids (Triggerfish) and two Lutjanids (Snapper) were recovered from this feature. Less common are the following taxa: Caesio sp. (Fusiliar), Labridae (Wrasse), Lethrinidae (Emperorfish), and Siganus sp. (Rabbitfish).

In addition to the fish and turtle bones recovered from WR-1, the assemblage contained a small amount of shell (gastropod and bivalve fragments that were not identifiable to a specific taxa) that was burned and highly fragmentary. It is unclear if this material represents food remains or if it is simply beach rubble that was incorporated into the combustion features. Burned and fragmentary bits of an exoskeleton of a lobster and a crab were also recovered in small quantities (2.6 grams total).

Fish Vertebral Measurements – Fish Body Sizes

A total of 202 fish vertebrae were measured in order to estimate the average size of the fishes represented in the assemblage. The vertebrae ranged from 2.8-20.0 mm in anterior width, representing fishes from about 16 cm in total length (TL) to 70 cm TL. The average body size of the reef fishes represented in this assemblage is 28 cm TL (as estimated from the average size of the vertebral centra in the assemblage, 6.6 mm). The standard deviation of the vertebral centra widths is 2.8 mm. It should be noted that the vast majority of the fish vertebra, and bone in general, are burned, which likely caused the bone to shrink slightly.

Fish Body Elements

Table 5. Identified fish bone elements from the Seven Site, Nikumaroro.
A total of 704 fish body elements were identified from the Seven Site assemblage. Of these the vast majority, 570 elements are vertebrae (Table 5). Only 128 elements, 22 %, are cranial elements and 576 bones or 78 % are postcranial. The average reef fish has about 56 cranial bones, between about 24 to 36 vertebrae, and numerous additional postcranial elements, including hundreds of bony spines and rays; note that this is an estimate, and depending on the fish species the number of bones overall and per body region varies widely. Regardless of the species of fish, the postcranial elements far out number the cranial elements by about three or four times in the average fish skeleton. The Seven Site identified fish assemblage includes a portion of cranial bones that approximates the natural distribution of cranial to postcranial bones in the average fish. I interpret this pattern as reflecting an unbiased deposition of fish in the archaeological record. That is, the person or people who cooked and consumed the fish represented in the Seven Sites threw out all the bones in virtually the same way (consuming all or part of each fish and disposing of all of the remains in the fire features). This depositional pattern is different from the pattern I have observed in Fiji where cranial bones are deposited differently than post-cranial bones, due to preference for the head and particular eating habits (Jones, in press). Moreover, fauna from archaeological sites I have worked on elsewhere in the Pacific Islands typically occur in midden contexts or earth ovens. Pacific Islanders generally do not cook fish on an open fire; when they do, the material deposited often reflects a biased deposition of bone. That is, the pattern of deposited bones results from preference, the way Pacific Islanders eat the whole fish and relish the head, and the habit of throwing bone refuse in areas that are distinct from the place where the fish is cooked.
1st dorsal spine 1
vertebrae 570
articular 10
atlas 12
basioccipital 1
cadual (scute, peduncle) 6
clethrium 2
misc cranial frags 3
dentary 32
hyomandibular 11
premaxilla 14
maxilla 21
pharyngeal plate 1
quadrate 14
vomer 6
Total 704

Niche Width/ Diversity and Equitability

The Seven Site fish and turtle bone were analyzed using the diversity and equitability measures described above (Appendix C). I did not include bird bone in this portion of the analysis because I did not identify the bird bone to species and did not identify the elements, therefore accurate MNIs could not be calculated. The bird bone should be sent to a specialist for identification.

The Shannon Weiner measure of diversity (H′) (or the variety of marine resources used at the site and their relative importance) for the Seven Site bone is 3.14. This level of diversity is moderate-high. Generally, more taxonomic categories lend to greater diversity. There are 30 taxonomic categories in the Seven Site assemblage.

Since diversity is calculated on a scale of one to infinity, the equitability measure V′ was used to standardize H′. When interpreting equitability values it should be recognized that equitability measures close to 1 indicate an even distribution of taxa, while lower values suggest dominance of one taxon or a few taxa. The calculated V′ value for this assemblage is 0.9236, suggesting a relatively even exploitation or use of taxa.  This even distribution of taxa and moderate to high diversity is the type of pattern one would expect when resources are exploited without preferences, resulting in a broad-based pattern of indiscriminate exploitation.  

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1 The fauna is in alphabetical order rather than taxonomic order in tables 2-3. 
2 In my database I made notes on that spreadsheet indicating bones that are identifiable that I was unable to identify. These make up less than 2% of the overall unidentified bone.
3 The Green sea turtle (Chelonia mydas) and the Hawksbill (Eretmochelys imbricate) have been recorded on Nikumaroro in marine biological surveys; both species are also known to nest on this island and to occur in abundance (Uwate and Teroroko 2007:46 & 53).

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