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
This report details identifications of bones (fish, turtle, and
bird) from The International Group for Historic Aircraft Recovery’s
(TIGHAR) 2007 excavations of the Seven Site, Nikumaroro, Phoenix
Islands, sent by Dr. Tom King to Sharyn Jones in September 2008.
The analyzed bone includes material from the following features:
SL-2, SL-3, and WR-1.
Methods
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.
Taxa |
NISP |
%NISP |
MNI |
%MNI |
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. |
Element |
count |
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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