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南太平洋海域調査研究報告 No.54（2014年12月）
OCCASIONAL PAPERS No.54（December 2014）

Integrated-Disciplinary Evaluation of Ecology-Economy
Interacting System in Marine Resources in Fiji
KAWAI Kei1, KOBARI Toru2, TORII Takashi2 and NISHIMURA Satoru3
1: Research Center for the Pacific Islands, Kagoshima University
2: Faculty of Fisheries, Kagoshima University
3: Faculty of Low, Economics and Humanity, Kagoshima University

Abstract
Republic of the Fiji Islands (Fiji) is one of the Melanesian countries. There are social systems
dependent on the nature that is highly productive for fishery resources in mangrove-coral ecosystems. Suchbeautiful natures and specific cultures are tourist resources for not only Fiji but also the other islands, but
the tourism has been resulted in various problems. Thus, it is a challenge to make a good living for island
people with “symbiosis” between the natures and human activities. In the present study, we evaluate therelationships of ecological and social systems on fishery resources in a Fijian local village from theviewpoint of natural and social sciences (integrate-disciplinary study).
In the objective village, there was a life style dependent on farming and fishing. The number of people
in a family was less than those in the neighboring village because young people were working in urban
areas or overseas to send living expenses to the village people. A major fishery resource was a bivalve“kaikoso” which was collected and sold by women and important seafood and income for the village
people. Kaikoso inhabited at the coastal sites between mangrove and coral reef and was more abundant thanthe other islands.
In this paper, we will show a simple model which factors have most affected the fishery resource andalso we introduce a significance to study the lure of islands from the viewpoint of “integrate-disciplines”.
Keywords: bivalves, ecology, economy, Fiji, integrate-disciplinary

Introduction
The Republic of the Fiji Islands (Fiji) is one of the Melanesian countries. Fiji’s socialsystems depend on a natural environment that has highly productive fishery resources inmangrove-coral ecosystems. This beautiful natural environment and Fiji’s many different
cultures are tourist attractions, not only for Fiji, but also for other islands in the region.
Tourism, however, has resulted in various problems. Thus, it is a challenge for island people
to make a good living while depending on the co-existence of nature and human activities. In48
KAWAI Kei, KOBARI Toru, TORII Takashi and NISHIMURA Satoru

the present study, we evaluate the influences of ecological and social systems on fisheryresources in a local Fijian village, from the interdisciplinary viewpoint of the natural andsocial sciences.
Natural environments and their resources are vital to human existence. Human activities
in many localities have led to environmental pollution and decreased biodiversity, and thisphenomenon has become global in scale. Understanding the relationship between humankind
and the nature from a global perspective is crucial.
In a traditional village, the lifestyle was dependent on farming and fishing. A bivalve
called “kaikoso,” which was major fishery resources, was collected and sold by women, andprovided important seafood and income for the village people. Kaikoso inhabited coastal sites
between mangroves and coral reefs, and is more abundant here than in the other islands.
The relationship between the nature and human activities encompasses a complicatedsystem affected by many factors. Therefore, the study of such systems requires aninterdisciplinary perspective (e.g., REPKO 2012). For example, coastal marine resource
management is related to a wide array of academic fields, including sociology, economics,and ecology. Consequently, it is preferable to study this topic from both ecological andsocio-economical perspectives, as advocated by interdisciplinary research.

Interdisciplinary Study
The primary component of the present study’s research method is the integrateddisciplinary evaluation of ecology and economics. A complicated ecosystem comprising tidal
flats, mangrove forests, and coral reefs is important to both the islands’ environment and its
society (Fig. 1), due to its high biodiversity and its residents’ reliance on marine resources for
consumption and commercial purposes.
Ecologists and economists participated in our research group, and although groupmembers focused on their own respective fields, collective meetings were held monthly. Also,
because field research occurred concurrently in the same village, a shared experience andunderstanding of kaikoso existed, which was further enhanced through frequent discussions.
Since group members shared their data, experiences, and thoughts, it was possible tocomprehensively

understandotheracademic

specializations

andtoconduct

aninterdisciplinary evaluation. Finally, group members proposed a conceptual model of theinteractions between ecological and economic systems and their relationships with the marine
resources, and assessed this model using a statistical method, namely, Structural Equation
Modeling (SEM) (BOWEN and GUO 2011).

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Integrated-Disciplinary Evaluation of Ecology-Economy Interacting System in Marine Resources in FijiFig. 1. The coastal area, coexisting mangrove forest, tidal flat, andcoral reef on the Viti Lavu Island in Fiji.

Study Site
The study village—Viti Lebu—is located on the eastern side of the main island of Fiji.
Although the mangrove forests are not rich, they grow in the island’s coastal areas; coral reefs
are present in the offshore areas (KAWAI et al. 2008, MANABE et al. 2008).
The village’s lifestyle is dependent on farming and fishing (NISHIMURA 2006). The
number of members in each household is less than the number of household members in theneighboring village. This is so because many youths are employed in the tourism industry,and live either in urban areas or overseas, and regularly send money home to sustain theirrelatives in the village. Kaikoso is a major fishery resource. It is collected by the women andsold to earn an income. Kaikoso is a bivalve, and feeds on organic matter in the seawater; itinhabits the coastal sites between mangroves and coral reefs, and is more abundant in Viti
Lebu than on other islands.

Objectives
This paper will begin by demonstrating the ecological importance of kaikoso tomangrove-tidal flat ecosystems, and the island’s economic and social systems. Then, a Fijian
village’s kaikoso resource management practices will be evaluated from a natural and social
science viewpoint. The model is simple, and considers which factors have most affected thisfishery resource, while also explaining the significance of studying the location from aninterdisciplinary perspective.

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KAWAI Kei, KOBARI Toru, TORII Takashi and NISHIMURA Satoru

The Impact of Kaikoso Feeding on Nature
An experiment was conducted to determine the importance of kaikoso feeding activities
on the mangrove-tidal flat ecosystem. Four aquarium tanks were prepared and filled withseawater, with one pair of tanks containing kaikoso and the other none. The dry weight of thesuspended particles and plankton biomass (i.e., food organisms for kaikoso) were compared
between both pairs of tanks. In natural seawater, suspended particles and plankton increased
without the kaikoso; however, in the presence of filter-feeding kaikoso, the opposite occurred.
This result is in agreement with BUHADI et al. (2013), who suggested that kaikoso feeding
plays an important role in the removal of tidal flat particles supplied by the mangrove.
Kaikoso is usually found near sandy shallow areas of tidal flats that are easily accessible
from the shore by foot. The average density of kaikoso varies between 13 and 15 each/m2(unpublished data). However, the density of a bivalve of the same genus in Kiribati isapproximately 5 each/m2. This suggests that even under the impact of an intense fishery, thedensities reported in Fiji are higher than those in other Pacific Islands. Furthermore, theresults indicate that kaikoso plays a very important role in the research location’s coastalecosystem.

The Economy: A Case for Women Collecting Kaikoso
A household survey was conducted to investigate the kaikoso fishing habits of women inthe village. The sample included 15 women who regularly collect kaikoso. The average
number of households surveyed was 4.3 ± 0.38 (mean ± SE), with an average income per
week of 116.7 ± 28.03 F$ (mean ± SE) (unpublished data).
The daily catch of kaikoso varied between 2 to 5 heaps, while the women’s weekly
catches were between 5 to 15 heaps, with an average of 11 (unpublished data). Each heap
includes approximately 65 individual kaikoso. Because each heap is worth 2 F$ at the Suva
Market, the weekly income generated from the kaikoso is 22 F$, or approximately 20%(22 F$/117 F$) of the total weekly income. These results indicate that kaikoso is a very
important source of income for the community.

Structural Equation Modeling: Natural-Social System Concept
A model depicting the relationship between the ecological and economic factors ofkaikoso fishing activities was developed. The natural and social parameters were collected inFig. 2 (unpublished data). Ovals indicate concepts describing natural-social systems. The51
Integrated-Disciplinary Evaluation of Ecology-Economy Interacting System in Marine Resources in Fijimodel’s hypothesis is that Fijian people have a “consciousness of the ecosystem’s service”
and a “monetary lifestyle,” both of which affect the environmental conditions of kaikoso andthe villagers.

Modeling Results
There were no significant interactions between villagers’ consciousness of theecosystem’s services and monetary lifestyles. However, villagers’ consciousness of monetarylifestyles significantly affected the number of kaikoso sold and collected. This means thatwhen a small amount of money is needed, the villagers collect kaikoso to sell at markets,
which subsequently indicates that sustainable resource use exists in the study location.

Summary1) The kaikoso feeding activities are of significant ecological importance to the tidal flatecosystem
2) The kaikoso is an important source of income for women in the village
3) SEM is a powerful tool for evaluating natural-social system concept, and interdisciplinary
research promotes a better understanding of the relationship between the nature andhumansFig. 2. Results of SEM. NS: not significant, S**: significant.

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KAWAI Kei, KOBARI Toru, TORII Takashi and NISHIMURA Satoru

Acknowledgments
The authors wish to express their thanks to Dr. Joeli VEITAYAKI for his kind help andcooperation in conducting the fieldwork and respiratory experiments at the University of theSouth Pacific. A portion of this study was supported by the Japan Society for the Promotion ofScience (JSPS) (21401013). This report was modified by the report of KAWAI et al. presented
at the 1st East Asian Island and Ocean Forum on 11 November, 2013, which will be publishedsoon.

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Anadara spp. in Fiji. Pacific Science, 67(4): 539-551.
KAWAI, K., KOBARI, T., MANABE, H. and ZANN, L. 2008. Fisheries and Marine Environmentsin the Coastal Area in the Island Coexisting Mangrove Forest and Coral Reef – A Case
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