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Kagoshima Univ. Res. Center S. Pal., Occasional Papers, No. 21, 33 - 38, 1991
Survey Team 2, Report4. The Progress Report of the 1990 Survey of the Research Project,
"Man and the Environment in Papua New Guinea"
33
NOTES ON MUnLuS POMPHuS CAPTURED FROM PORT MORESBY AREA,
PAPUA NEW GUINEA
Kazushige TANABE, Junzo TsUKAHARA, Akihiko SHINOMIYA
and Kimihiko OKI'
Introductio∩
Chambered nautiles (genus Nautilus LINNAEUS, 1758) is one of the well-known living
fossils, which belongs to the family Nautilidae of the cephalopod molluscs. Among five
or six currently recognized species of Nautilus, N. pomDilius LINNAEUS, 1758 has the widest
geographic range in the tropical South Pacific from the Philippines in the northwest to
American Samoa in the southeast (SAUNDERS, 1987).
During the expedition in Papua New Guinea by T. V. Keiten一maru in November -
December, 1990, with the aid of bailed traps we collected live animals of N pompilius and
other nektobenthic fauna from the water in the southeast of Port Moresby. In this report
we describe the trapping records and biological data ot the captured Nauh'lus.
Trapplng Records
1) Methods of trapping
Trapping experiments were carried out using the R. V. Somber of the Motupore Island
Research Center, at six points (Tl-T6) in Padana Nahua Channel, about 15 km ESE from
Port Moresby City (Fig. 1). A single entry wireイlamed crab pot of about 150 cm (basal
diameter) Ⅹ loo cm (height) size COVered by the nylon net (1.5 cm in mesh size) was used
in trapplng.
Menu 三,:,-++
∴1、 -..i;....i.;.?.
I.._.?.i:.''.-.∴言.S'-ヽ宗主
くさ.,.
9035'S
147 彦ィテ2
T5--●_Je
015.と†2●●
・eeo.亨態 ...、.、."《
PortMoresby
0 凵怎012tm
coRALSEA'-.
eilT'
Fig. I. Map of Padana Nahua Channel, southeast of Port Moresby, Papua
New Guinea, showing the trapping locations. Dotted line indicates
20 m contour line.
34
K. TANADE al al.
Two crab pots with bait (Japanese sardine) Were set in the morning on the bottom
with a line and attached to the surface buoy with a floating line, and drawn up the next
morning. Trapping points and their depths were determined by a triangular net on navigational
markers and the echo-sounding profiles respectively. All of the trapping points are located
at the abruptly dropping scarf of the outer reef margin (see eKI et al. in this volume).
2) Basic data of Nautilus
As a result of six trapping trials, a total of 34 individuals of N. Dombilius were captured
from five points at either 200 m or 250 m in depth (Table 1). Other animals in the traps
were extremely rare, and only two large conger eels were found in one of the traps at
T6. At T3 (140 m in depth) We only collected three snappers.
Table I. Measurements of the specimensii Of Nautilus bomDilius captured
from the Port Moresby area, Papua New Guinea in 1990.
.B.::C..iO.fn specimen Sex T。.a.Wei:shstue'g'sh。1- SDhel霊(mmi 鰭/DFormH,rDatio:,H Re-arks
Nov. 21-22 PM-I M 663.5 511.4 140.5 149.1 76.6 97.3 .514 .653 .787 Dissected(Nov.22)
TR-I(200m) PM-2 M 609.3 450.I 152.8 149.2 74.7 95.7 .501 .641 .781 ditto
PM-3 M 558.8 408.2 145.3 148.0 71.8 94.8 .485 .641 .757 ditto
Nov. 21-23 PM-4
TR-2(Zoom) PM-5
PM-6
PM-7
PM-8
PM-9
PM-10
PM-ll
Died (Nov. 23)
ditto
ditto
ditto
ditto
ditto
ditto
ditto
Nov. 23-24 PM-12 M 823.4 634.3 179.3 165.7 79.5 103.3 .480
TR-6(200m)
.623 .770
Dissected (Nov. 24)
Nov. 23-24
TR-5(250m)
Nov. 23-24
TR-4(250m)
Naulilus PomPilius Captured from Port Moresby Area, PNG
35
After capture, each animal was labeled, weighed, sexed and measured following the
methods described elsewhere in the previous reports (TANABE, 1985, 1988). The captured
animals consisted of mature or submature males only. Soft and shell parts of each animal
were removed separately, and weighed by means of a dial scale (accuracy±0.01 g) (Table
1). Furthermore, fresh gonad and a small piece of mantle were removed from the soft
tissue of 26 animals from four points (Tl, 4, 5 and 6). They were frozen or fixed for
further genetic and/Or histological examinations.
Although we did the trapping experiments during a limited period in November, the
absence of females in the total catch seems to interesting. Such an extremely high male/
female ratio was recognized in the large samples of N. Dompilius from Fiji (date of capture :
August - September, 1983 and 1986)(TANABE, 1985, 1988)・
Discussion
Distribution of N. bomDilius in the waters around Papua New Guinea has been documented
in a number of references literatures (WILLEY, 1895 ; SAUNDERS & DAVIS, 1985 ; SAUNDERS,
1987 among others). Morphological variation within and among populations in this region
has been further analyzed by SAUNDERS & DAVIS (1985) and SwAN & SAUNDERS (1987).
Measurements of the specimens from the Port Moresby area correlate well with the data
by these authors.
The widespread species N. DomDilius exhibits high levels of genetic and morphological
differentiation among local populations (WooDRUFF et al., 1987 ; SwAN & SAUNDERS, 1987 ;
TANABE & TsuKAHARA, 1987 ; TANABE et al., 1990). It is also closely allied morphologically
to the population from Palau distinguished as N. belauensiS SAUNDERS, 1981, suggesting that
the latter merely represents a geographic variant of the former, or otherwise they are closely
related sibling species (TANABE et al., 1990). Summarization of the available measurements
tor large collections ot N pomDilius from the Philippines, Fiji and Papua New Guinea (Port
Moresby area), and of N. belauensis from Palau shows that the Port Moresby population
is intermediate in shell size, animal weight and shell proportion at maturity between the
Fiji and Philippine populations (Figs. 2-4).
SAUNDERS & DAVIS (1985) first described the sympatric occurrence of N・ bomDilius and
N. scrobiculatus lLIGHTFOOT, 1786] in the waters off Manus Island, about 800 km north ot
Port Moresby. These two species are easily distinguished both genetically (WooDRUFF et
al., 1987) and morphologically (SwAN & SAUNDERS, 1987). Furthermore, specimens of N
pomDilius from Manus Island are essentially similar in external shell morphology, Coloration
and size to those from the Port Moresby area. The phylogenetic relationships and the
isolation mechanism of the two species, however, have not yet been sufficiently elucidated.
We should further investigate these problems from comparative morphological, ecological
and genetic points of view.
Acknowledgment. We thank Dr. Neil H. LANDMAN for critical reading of the manuscript・
36
K. TANABE at al.
500 1000 1500
0 0 TヤUtuT比T
皿_h33‥3629"39
0 1 SfニFSr
PALAU 麻モSri_-1255 偵S
2○=〃漢音■漢音〇一〇〇
oo●'500 ii 姪*リ,カs*r
wEIc HT (9)
Fig. 2. Geographic variation of the total live weight for male specimens
of Nautilus DomCilius from Fiji, Papua New Guinea, Philippines
and N. belauensおfrom Palau. Data for the Fiji, Philippine and
Palau populations are from TANABE (1985, 1988), HAYASAKA et
al. (1982) and TANABE (in prep.) respectively.
FIJI h316●
_.88 iBlCC.7lTllTl
opApUANEWcUINeAh=28
i=156.2mm 0
Om..150.i200.
: 'lu THI:Ip:'ipLiO・'f・3.-
opALAUr"7 oi=2017m 〇一
.m o
1000150 "メ
SHEししoIAM∈T∈鼠(mm)
Fig, 3. Geographic variation of shell diameter for male specimens of
Nautilus DomDilius from Fiji, Papua New Guinea, Philippines and
N. belauensiS from Palau. Data for the Fiji, Philippine and Palau
populations are from TANABE (1985, 1988), HAYASAKA et al. (1982)
and TANABE (in prep.).
1.0
Nautilus Pombilius Captured from Port Moresby Area, PNG
・Fij主N=164
・ phi一ippines, N=10
●palau,Nニ57
年papua New Guinea,N=28
〟
事享"十●
・‡隷;.
●● ●●
-・.. !..
●
●:㍗.〟
● ●● ′
∫
●● ● ● ● ●
●
● ●
150
Diameter (mm)
200
37
Fig, 4. Scatter plot of shell breadth/height retio vs. shell diameter for
male specimens of Nautilus pomDilius from the Philippines, Fiji
and Papua New Guinea and N. belauensis from Palau. Data tor
the Fiji, Philipplne and Palau populations are from TANABE et
al. (1990).
References
HAYASAKA, S., SAISHO, T., KAKINUMA, Y., SHINOMIYA, A., OKI, K., HAMADA, T., TANABE,
K., KANIE, Y., HATTORI, M., VussE, F.V., ALCALA,し., CoRDERO, P.C. Jr., CABRERA, J・
J. & GARCIA, R. G. 1982. Men. Kagoshima Univ. Res. Ctr. S. Pacific, 3: 67-137.
SAUNDERS, W. B. 1987. ''The species ot Nautilus. "Nautilus. The biology and paleobiology
of a living fossil (eds. SAUNDERS, W.B. & LANDMAN, N・ H・), 35-52・ Plenum, New York・
- & DAVIS,し.E. 1985. S°i. Papua New Guinea, ll: 60-69.
SwAN, A. R. H. a SAUNDERS, W. B. 1987/.Morphological variation in Nautilus trom Papua
New Guinea. "Nautilus. The biology and paleobiology or a living fossil (eds. SAUNDERS
W.B. & LANDMAN, N.H.), 85-104. Plenum, New York.
TANABE, K. 1985. Kagoshima Univ. Res. Ctr. S. Pacific, Occas. Paps., 4: 10-17.
- 1988. Kagoshima Univ. Res. Ctr. S. Pacific, Occas. Paps., 15: 5-14・
- & TsUKAHARA, ∫. 1987. ``Biometric analysis of Nautilus DomDilius from the Philippines
and the Fiji Islands. ''Nautilus. The biology and paleobiology or a living Fossil (eds. L
ANDMAN, N.H. & SAUNDERS, W.B.), 105-113. Plenum, New York.
- , - & HAYASAKA, S. 1990. Malacologia, 31: 297-312.
WILLEY, A. 1895. Nat. S°i., 6: 405-414.
WooDRUFF, D. S., CARPENTER, M. P〟, SAUNDERS, W. B. & WARD, P. D. 1987. "Genetic variation
and phylogeny in Nautilus・ ''Nautilus・ The biology and paleobiology ot a livlng FOSSIL
(eds. LANDMAN, N.H. & SAUNDERS, W. B.), 65-83. Plenum, New York.