Kagoshima University Research Center for the Pacific Islands, Occasional Papers No.34, 95-100, 2001
Part 1, Section 3, Report 2. The Progress Report of the 1999 Survey of the Research Project“Social Homeostasis of Small Islands in an Island-zone”

95

THE SUPPLY OF ENERGY -SOURCE FOODSTUFFS IN THE YAP ISLANDS:
A PRELIMINARY REPORT
Kazutaka NAKANO

Abstract
Can the Yap Islanders subsist after the foreseeable end of systematic aid programs by the US
Government? A preliminary survey of present and future supply of energy-source foodstuffs for the
Yap islanders was conducted. Among several starchy crops harvested on the islands at present, giant
swamp taro is the islanders’ preferred staple. Its yearly land productivity was calculated at 8 million
kcal/ha roughly, which is comparable to that of the true taro produced in Oceania. The average ratioof the calorific intake of giant swamp taro to total daily intake was tentatively calculated at two thirds
for the islanders. The ratio for rice, totally imported from the US, was calculated as less than a quarter.
Thus, the islands supply the islanders with most of their energy-source foodstuffs. Without the systematic aid programs extended by the US Government, the future prospect for islander subsistence
seems not quite hopeless. However, this will depend on local policies and the attitudes of the islanders
towards cultural change.
Key words: staple food, sustainability of food supply, productivity, consumption, Yap Islands

Introduction
Since the end of World War II, most of the Micronesian islands were under US Government
control until their respective times of independence. Even after political independence the island
countries relied heavily on the US for financial aid to prevent the decline of their economies.
However, the aid amount to the Federated States of Micronesia (FSM) is now being decreased
year by year and will approach zero in a few years. At this time, given the lack of exportablemerchandise to balance the FSM’s international trade, how can the people in the islands subsist?
To answer this question for the Yap Islands which come under the Government of Yap State, oneof the four states of the FSM, I conducted a preliminary survey on present and future supply ofenergy-source foodstuffs.

Energy-source Food Crops Grown on the Yap Islands
From Table 1 in FALANRUW (1994), the following starchy food crops commonly grown on
the Yap Islands can be noted: breadfruit (Artocarpus spp.), true taro (Colocasia esculenta (L.)
SCHOTT), pumpkin (Cucurbita maxima DUCH.), giant swamp taro (Cyrtosperma chammisonis(S CHOTT) M ERRILL), at least five species of yam (Dioscorea spp.), sweet potato (Ipomoea
batatas (L.) LAM.), cassava (Manihot esculenta CRANTZ.), bananas (Musa spp.) and tannia, another kind of taro (Xanthosoma sagittifolium (L.) S CHOTT). Of these crops, at the present timethe most important one seems to be giant swamp taro (F ALANRUW, 1994), which is always
grown in a swampy patch, usually without a fallow period. On the other hand, true taro, whichis considered important for its prestige rather than as a staple (FALANRUW, 1994), is grown inboth swampy and upland patches. Neither species can survive in a swamp with salty water. The

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Kazutaka NAKANO

islanders, however, often convert mangrove areas to taro patches after great and time-consuming
effort. Whereas true taro always requires very sunny patches, giant swamp taro is a more shadetolerant crop and, although it takes a much longer time for its corm to mature, weeding intensity
need not be very high. Furthermore, once the high leaf layer of this crop is densely established,
few weeds can surmount it, as its name, “giant” swamp taro suggests. However, according tosome experts, the area planted with cassava is increasing substantially in the Yap Islands in linewith a world-wide trends in the tropics.
Besides the starchy food crops mentioned above, coconut (Cocos nucifera L.) must be included as an important energy-source foodstuff, because it is consumed daily by the islanders
and contains abundant oil, which has double the energy content of starch.

Land Productivity of Giant Swamp Taro in the Yap Islands
A preliminary estimate of the land productivity of the edible portions of giant swamp taro
on the Yap Islands can be made step by step as follows:
1) at some actual taro patches, the distances from the growing points of individidual plants to thenearest “others” were actually measured;2) using the distribution model shown in Fig. 1 and the mean value of the distances explained
above, the average number of individual plants per hectare was estimated;3) because one individual plant produces one tuber for normal consumption, the average weightof the edible portion of a tuber was multiplied by the value estimated at 2), giving an estimateof land productivity for edible portions of giant swamp taro for the period from planting time toharvest;4) because tubers are harvested several years after planting, to estimate yearly land productivity,

Fig. 1. Distribution model of the individual plants of giant swamp taro grown in a patch.

The Supply of Energy-source Foodstuffs in the Yap Islands: A Preliminary Report97

the value obtained at 3) must be divided by the average time elapsing from planting until harvest.
The results of the estimation procedure explained above are indicated below:
1) the mean value of the distances between the nearest individual plants is, as shown in Fig. 1,
88.5 cm, with a standard deviation of 23.17 (n = 39);2) according to the distribution model (Fig. 1), planting density is calculated at nearly 15,000 individuals (i. e., 15,000 tubers) per hectare;3) the mean value of the 14 samples of edible portion actually measured at the shops was 1.33
kg (fresh weight). Thus, 1.33 kg/tuber× 15,000 tubers/ha = 19,9500 kg/ha ≒ 20 ton/ha;4) most tubers are dug up between 3 and 4 years after planting (according to UNTAMAN (1982)
the interval is usually 4 years). Thus, if the interval is 3 years, yield = 6.7 ton/ha; if 4 years,
5.0 ton/ha yearly.
Because I was able to stay in the Yap Islands only for a short period, the amount of information available for estimating the land productivity of giant swamp taro is somewhat inadequate. Still, on the rough estimates mentioned above, the yield of edible portions is 6 ton/hayearly. This value is similar to VICKERS’ (1982) tentative estimate (namely, 7.5-10.0 ton/ha for
a growth period of between 18 months and 2 years), and converts to 7,860,000 kcal using
FRENCH’s (1986) data, or 8,440,000 kcal using M AY & ANIANI’s (1984) data. These values forthe energy content of giant swamp taro are in the range of those for true taro and giant taro
(Alocasia macrorrhiza (L.) SCHOTT) sampled in the South Pacific region (HONGO & OHTSUKA,
1993). If we adopt an intermediate value between the preceding two, the calorific yield of edible
portions may be roughly considered to be 8,000,000 kcal/ha yearly.
When this estimate is compared with the yield data of true taro produced in Oceania, excluding the data obtained from fertilized patches, it is low but not outside the range of the data
in anonymous (1982). This finding does not change even if we take into account other data, suchas in O NWUEME (1978) and O HTSUKA (1994).
In conclusion, the land productivity of giant swamp taro in the Yap Islands is comparable
to that of true taro grown on unfertilized patches in Oceania, even after allowing for the fact thattrue taro is usually harvested in less than a year after planting time.

Consumption of Giant Swamp Taro in the Yap Islands
The estimation of per capita daily consumption of foods is notoriously difficult and inaccurate without a person-to-person watch on sampled subjects over a long period. Because circumstances did not allow me to conduct a precise survey and accurately estimate the islanders' daily
consumption of giant swamp taro, I was obliged to rely on information from interviews with people in villages and in one town, Colonia. Most adults eat giant taro twice daily, while some eat
it three times and some only once. The usual consumption at one sitting was suggested by showing me the amount of actually consumed tuber. Thus, the daily consumption of a male adult was
tentatively estimated at about 800g in fresh weight. Based on this value, the mean daily consumption of the islanders was calculated, using sex-age data on the population (anonymous,
1996) and the following values (adapted from H INTON, 1969) in International Scale of Man
Units*:
Age in years
0- 4
5- 9

Male
0.25
0.50

Female
0.25
0.50

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Kazutaka NAKANOAge in years
10-14
15-49
50+

Male
0.75
1.00
0.90

Female
0.75
0.80
0.80

Thus by my calculation explained above, the per capita daily consumption of giant swampt taro
in the Yap Islands is nearly 1,200 g, which converts to about 1,600 kcal using the intermediate
value of energy content mentioned above (FRENCH,1986; M AY & A NIANI, 1984).
According to data based on the FSM 1988 National Nutrition Survey (anonymous, 1997),
per capita daily calorific intake in the FSM is 2,400 kcal. If this value (although its accuracy
may be somewhat problematic) is applied here, approximately two thirds of the calorific intake
of a Yap islander is supplied by giant swamp taro. This ratio seems a little too high. The reason
for the possible overestimate may be that the islanders did not always indicate to me the sizesof the tubers actually consumed, but rather “ideal” ones for ingestion, and also that, although I
used the value 2 for the daily times of ingestion of giant swamp taro, the error owing to rounding
this number may be serious. Furthermore, the islanders do not always consume all of the cooked
quantity of a staple food at each sitting and often abandon the residue. Moreover, they probably
cook of other starchy foodstuffs harvested on the islands, such as true taro, in place of cooked
giant swamp taro rather than in addition to it. In spite of my possible overestimate, the preceding
tentative values for the present per capita daily consumption of giant swamp taro in calorificterms in the Yap Islands can be treated seriously.

Quantitative Importance of Rice Consumption in the Yap Islands
From general observation, the quantitatively important energy-source foodstuff next to giant
swamp taro in the islands seems to be rice, which is totally imported from the US. To estimate
the weight quantities imported annually, the data in the book of official statistics (anonymous,
1998a) are not very useful because only the amount of money paid for the imported rice is shown
there. Furthermore, the book does not show data for the Yap Islands as such but only for Yap
State. Based on these figures, nevertheless, we can estimate the weight quantities of rice annually imported for the consumption of the Yap Islanders.
According to one source, the amount of money paid for rice import to Yap State in 1996
was US$178,810, a drastic decrease from the amount paid in 1995, $245,834 (annonymous,
1998a). The first problem to consider is whether these values are based on CIF or FOB price.
I fortunately was able to persuate the leading merchant on the islands to give me copies of all
the papers of invoice which show CIF prices of rice for his orders in 1996. Another merchantgave me copies of papers where shipping charges for the freight of rice are indicated.
Combining these data, we can conclude that the preceding official statistics are based on FOB
price, since, if they were based on CIF price, the calculated total weight of rice imported to Yap
State in 1996 would have been less than the total import weight reported by the above-mentioned
two merchants in 1996. Calculating the export price (FOB) in the USA for 1995 and 1996 bymeans of FAO’s data, we obtain the price values US$323 and $390/ton respectively (anonymous, 1998b). If these are applied here, the total weight of rice imported to Yap State in 1995
and 1996 was 761 and 458 tons respectively. Owing to a distinct rise in the export price in the
US during from 1995 to 1996, the relative difference in the total weight of imported rice forthese two years is much greater than the relative difference in the amounts of money paid for

The Supply of Energy-source Foodstuffs in the Yap Islands: A Preliminary Report

99

imports. The leading merchant explained to me the prime reason for the drastic decrease of riceimport to Yap State in 1996. It was that the outer islanders of Yap State suffered disastrous typhoon damage that year and thus directly received large quantities of foodstuff, including rice,through the local US agent under the terms of a special aid program for them. As a consequence,
they did not need to purchase much rice from the merchants in the Yap Islands and, necessarily,
the quantity of imported rice dropped drastically from the previous year.
Taking this into account, we can estimate that most of the rice imported into Yap State in1996 was consumed by the Yap Islanders. If their total population is estimated to be approximately 7,000 (anonymous, 1996), then their per capita daily consumption of rice was roughly
180 g. This value is obviously an overestimate, because, even if the quantity sold to the outerislanders was small, it was not zero. Thus, the per capita daily consumption of rice in the Yap
Islands in 1996 is here estimated tentatively at 160 g, which converts to a little more than 500
kcal, that is, less than a quarter of 2,400 kcal, which the National Nutrition Survey mentioned
above gives as the per capita daily calorific intake in FSM (anonymous, 1997).

Future Prospects and Conclusion
The Yap Islanders are generally said to be upholders of tradition. And indeed most of theirenergy-source food intake seems to be still derived from crops traditionally harvested on the islands, as indicated above. Of these crops, giant swamp taro is most prominent. Reportedly, potential areas for new taro patches have not yet been fully utilized. However, in the Yap Islands
we very often heard about and observed symptoms of taro blight, the cause of which has notreally been identified yet. The damage caused by this blight is becoming serious. Furthermore,
inasmuch as the cooking time for giant swamp taro is rather lengthy, about one hour
(U NTAMAN, 1982), it is not suitable for people who commute to an office every morning.
Besides being unsuitabe for people adopting a modern life style, other disadvantages are that few
young people like working in a muddy swamp to grow it, and while children on the islands prefer rice, by far, to taro, partly because the latter is hard to chew.
Given the present size of the islander population, self-subsistence and sustainability in the
production of energy-source foodstuffs in the Yap Islands is quite possible. The last resort forincreasing production of energy-source foodstuffs could be enlargement of the production area
for cassava in the vast savannah grasslands available (more than one fifth of the islands in area
(N AKANO et al., 1987; FALANRUW et al., 1987)), where soil fertility is probably sufficient. On
Batiki Island in Fiji the production of cassava in such grasslands has already become dominant(BAYLISS-SMITH, 1978).
In conclusion, whether the Yap islanders can subsist without a systematic aid program will
depend on local policies and the attitudes of the islanders towards cultural change.

References
Anonymous 1982. “The cultivation of taro: Colocasia sp.” Taro cultivation in the South Pacific(ed. LAMBERT, M.): South Pacific Commission handbook, no. 12, 10-31, South PacificCommission, Noumea, New Caledonia.
1996. Yap State detailed tables: 1994 FSM census of population and housing. 16 + 342
pp. Office of Planning and Budget, Yap State Government, Colonia, Yap, FSM.
1997. Yap State: Agricultural marketing assessment and guidelines (Prepared under the
Asian Development Bank Technical Assistance to the Federated States of Micronesia,

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Kazutaka NAKANO

Department of Resources and Development for the Strengthening of Agricultural Support
Services, TA Project No. 2484-FSM). 8 + 79 pp. Yap State Division of Agriculture andForestry and Yap State Division of Commerce and Industry, Colonia, Yap, FSM.
1998a. “Chapter A: Exports and imports by FSM and each state, 1992-1996.” Federated
States of Micronesia trade bulletin, no. 9, 1-105, Statistics Unit, Department of Economic
Affairs, FSM Government, Palikir, FSM.
1998b. FAO trade year book, vol. 50, 1996. 31 + 398 pp. FAO, Rome.
BAYLISS-SMITH, T. P. 1978. “Batiki in the 1970s: satellite of Suva.” The small islands and thereefs: Island reports 4, the UNESCO/UNFPA population and environment project in theeastern islands of Fiji (ed. BROOKFIELD, H.), 67-128, Australian National University,
Canberra.
FALANRUW, M. V. C. 1994. Isla: A Journal of Micronesian Studies, 2:5-22.
, WHITESELL, C. D., COLE, T. G., M ACLEAN, C. D., & A MBACHER, A. H. 1987.
Vegetation survey of Yap, Federated States of Micronesia. 9pp. + 11 folded maps. PacificSouthwest Forest & Range Experiment Station, Berkeley.
FRENCH, B. P. 1986. Food plants of Papua New Guinea: A compendium. 5 + 405 pp. Australian
Pacific Science Association.
H INTON, P. 1969. The Pwo Karen of northern Thailand: A preliminary report. 65 (text) + 29
(notes and other items in addition to text) pp. Tribal Research Center, Chiangmai, Thailand.
(Mimeo.)H ONGO, T. & O HTSUKA, R. 1993. Man and Culture in Oceania, 9: 103-125.
M AY, R. J. & A NIANI, K. 1984. A guide book to bush foods, markets and culinary arts of Papua
New Guinea. 5 + 178 pp. Robert Brown & Associates, Bathurst, Australia.
N AKANO, K., POLLOI, K., & A YIN, L. O. 1987. “On the devastated grassland in Palau and Yap,
the Western Carolines.” The prompt report of the 5th scientific survey of the South Pacific(ed. N AKANO, K. et al.), 10-14, Kagoshima Univ. Research Center for the South Pacific,
Kagoshima, Japan.
O HTSUKA, R. 1994. Man and Culture in Oceania, 10: 103-115.
O NWUEME, I. C. 1978. The tropical tuber crops: Yams, cassava, sweet potato, and cocoyams.
14 + 234 pp. John Wiley & Sons, Chichester, New York, Brisbane, and Toronto.
U NTAMAN, V. 1982. “Cultivation of giant swamp taro Cyrtosperma chamissonis (SCHOTT)MERR. in Yap, Trust Territory of the Pacific Islands.” Taro cultivation in the South Pacific(ed. L AMBERT, M.): South Pacific Commission handbook, no. 12, 97-100, South PacificCommission, Noumea, New Caledonia.
V ICKERS, M. E. H. 1982. The agronomy of Cyrtosperma chamissonis (SCHOTT) M ERR . in
Kiribati. Taro cultivation in the South Pacific (ed. LAMBERT, M.): South PacificCommission handbook, no. 12, 90-97, South Pacific Commission, Noumea, New
Caledonia.

Note*A measure first used in the 1960s (HINTON, 1969).