Measuring mangrove-fishery benefits in the Peam Krasaop Fishing Community, Cambodia
Introduction
The role of mangroves in enhancing fishing production for coastal fishing and thus providing important income and subsistence to fishing communities is now widely recognised (Carrasquilla-Henao and Juanes, 2017; Hutchison et al., 2014; Manson et al., 2005). Also recognised is that loss of mangrove area for other uses will likely have negative impacts on fisheries productivity in such communities, due to a reduction in available fish habitat (Barbier, 2007; Brander et al., 2012; Estoque et al., 2018). Hence, several studies have reported the regional economic value of mangroves, or reported positive correlations with fisheries catches, to promote their economic value in land use planning (Aburto-Oropeza et al., 2008; de Graaf and Xuan, 1998; Kenyon et al., 2004; Ley, 2005; Loneragan et al., 2005; Malik et al., 2015; Ronnbaack, 1999; Vázquez-González et al., 2015).
At the household level, estimates have shown mangrove associated catches to make substantial contributions to household incomes (Abdullah et al., 2016; Aye et al., 2019; Barbier, 2006; Malik et al., 2015; Rumahorbo et al., 2019). Thus for example, using a Total Economic Value method, Malik et al. (2015) estimated that mangrove-fishing households in the Takalar District, South Sulawesi, Indonesia receive an annual net use value of 1221 US$, 1088 US$ and 480 US$ from fish, crab and shrimp capture respectively. In the Ayeyarwaddy Region, Myanmar, Aye et al. (2019) estimated that 43% of household income comes from mangrove products, of which 73% is from mangrove-fishery products. Mangrove-fishing communities can therefore have high dependency on fishery products for their economic income.
Studies conducted from a socio-ecological perspective have found mangrove-fisheries to be complex socio-ecological systems. For instance, mangrove-fishers in the Sao Francisco River Estuary, Northeastern Brazil, reported exploiting at least 2 different fishery resources (88% of fishers interviewed) and fishers often (75% of those interviewed) targeted all resources available (which included a number of fish, crab, mollusc and shrimp species) (Santos et al., 2017). In the Ciénaga Grande de Santa Marta lagoon system in the Colombian Caribbean, mangrove-fisheries were also multi-species and multi-gear in nature, with 5–9 species within catches across communities and 8 different types of fishing gear. Over a 10 year period, both spatial and temporal patterns in fishing sites were variable, in part related to the use of different gear types (Carrasquilla-Henao et al., 2019). Individual mangrove-fishing communities can also show a high degree of localism in their socio-ecological characteristics (Hoque Mozumder et al., 2018). As a result, understanding the system's unique seasonal and spatial interactions with mangrove becomes important for appropriate management. Yet reporting on these complex interactions has been limited (Hoque Mozumder et al., 2018). Further, many quantitative valuations of mangrove resources been limited to single fishing sectors, gear types or species groups. Estimates that fail to capture the full diversity of fishing practices may, therefore, underestimate the true socio-economic benefits of mangrove-fishing.
Moreover, many studies take a snapshot view of mangrove use by fisheries, often using annual catch statistics which do not elucidate either the spatial or the temporal variability in the benefits received. Research on the impact of fishing on mangrove fish assemblages has also highlighted the importance of understanding the spatial distribution of fishing pressure in mangroves, as both fish species abundance and richness has been found to be lowest in areas of high fishing pressure, with richness and presence of larger bodied fish being highest, and at similar levels, in areas of lower fishing pressure and areas of no fishing (Reis-Filho et al., 2019). Understanding all the ways in which communities interact with the mangrove, both spatially and temporally, is also important. Undervaluation of mangrove value to communities can lead to land use decisions that do not take into account important services needed for community livelihoods. The use of local ecological knowledge to better understand mangrove socio-ecological systems should be encouraged (Reis-Filho et al., 2019; Santos et al., 2017). This study therefore aims to take a more holistic, yet still quantitative, view of the benefits mangrove-fishing communities receive from all fishing activities associated with mangroves.
An increase in human occupancy on the 435 km coastline bordering the Gulf of Thailand, particularly in the past two decades, along with fishery expansion, has put pressure on coastal resources in Cambodia. Declines in both fishing productivity (catch per unit effort) and mangrove extent have been observed (Srean, 2018). Data on coastal fishing is lacking from Cambodian fisheries statistics, as management in Cambodia has focussed mainly on inland fishing thus far (Teh et al., 2014). In particular, small-scale coastal fisheries are most likely underreported (which includes artisanal and subsistence activities), as landings statistics only consider catches taken by taxable vessels (Teh et al., 2014). Boats with engines of 30 horse power or less, which are characteristic of those used by mangrove-fishers, do not appear in such returns. To capture these small-scale activities, this study uses socio-economic interview surveys to collect quantitative data from local fishers at a case study site in Cambodia. Total landings estimates were sought from fisher interviews and a market price method, a method of ecosystem valuation used to estimate the value of products sold in commercial markets based on current market prices, was conducted. Throughout this study, the objective was to estimate the benefits received by the community through catch and income from mangrove-fishing.
Fishing communities in the Peam Krasaop Wildlife Sanctuary (PKWS), Koh Kong Province, Cambodia are highly dependent on the local mangrove forest (PMMR team, 2000). Qualitative studies of the PWKS have suggested that the communities are involved in gathering of invertebrates in the mangrove and offshore fishing for fish and invertebrates, as well as some mariculture activities (PMMR team, 2000). The value derived from mangrove ecosystem services can influence land use decisions; a holistic overview of the socio-economic importance of mangroves is therefore important in the management of mangroves and their associated resources. Where mangrove-fishery interactions are complex, as in Peam Krasaop, exposing the intricacies of mangrove-fishery value to communities is especially important. This study therefore aims to i) quantify the mangrove benefits from all of these activities, and, through interviews with local fishers, ii) determine when and where mangrove-fishery benefits are derived by the community.
Section snippets
Location
The Peam Krasaop Wildlife Sanctuary (PKWS), Koh Kong Province was designated as one of 23 Protected Areas (PA's) in Cambodia in 1993. The protected area covers 25,897 ha and includes 23,750 ha of mangrove forest (2003 estimate; Fig. 1) (Dara et al., 2009). It also makes up 60% of the Koh Kapic and Associated Islets site, a Wetland of International Importance under the Ramsar Convention, incorporated into the Convention in 1999 (Pillai, 2003). The PKWS hosts 64 mangrove species. Along the
Social and historical context of the Peam Krasaop Fishing Community (PKFC)
The Peam Krasaop Fishing Community (PKFC) is a newly formed fishery. There has been a complex history in the past 40 years, including mangrove destruction for charcoal production, the subsequent ban on charcoal production enforced by the provincial authority to protect the mangrove forest from cutting, and therefore changing uses of mangrove by the community (Fig. 2). In 2004, in order to provide villagers with access to facilities such as schools and health care, and to offer new job
Discussion
The PKFC is highly dependent upon mangrove-associated fish and invertebrate catches. The estimate of 90% of the total fishery catch landings of mangrove-associated species is a conservative one, as species groups with any non-mangrove associated species, regardless of proportion in that group (such as grouper and shrimp species), were coded as non-mangrove associated species. There is, however, a large range of catch volumes and gross incomes between households in the PKFC. This estimate of
Conclusions
In Cambodia, year-round mangrove-fishing livelihoods are maintained through seasonal switching between gathering, fishing and mariculture activities, with the majority of catch and income being derived from mangrove-associated species. The complexity of mangrove-fishing activities, through varying target species, locations and seasons, and diversity of activities within households, makes definitive quantification of mangrove ecosystem service value challenging. Furthermore, there are leaders
CRediT authorship contribution statement
Rachel Seary: Investigation, Formal analysis, Writing - original draft, Conceptualization, Methodology. Tom Spencer: Supervision, Writing - review & editing, Conceptualization, Methodology. Mike Bithell: Supervision, Writing - review & editing, Conceptualization, Methodology. Chris McOwen: Supervision, Writing - review & editing, Project administration, Conceptualization, Methodology.
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgments
This research was supported by the Nippon-Foundation Nereus Program (https://nereusprogram.org/). The fieldwork aspects of the project were funded by the Royal Geographical Society (with IBG). We thank Kheang Ratana and Sum Dara for their role as interpreters, and Isobel Shears for her research assistance, during the field period in Cambodia. This research would not have been possible without the participation of the Peam Krasaop Fishing Community. To them we extend a special thanks.
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