About the Author
Author

Kini Koto (aka KK) is a WCS Fiji Field Officer and our resident freshwater expert. He often performs the traditional ceremonies carried out at the start and end of our village visits or workshops - the sevusevu and tatau.

Mapping barriers to fish migration

WCS Fiji field officers recently completed a mission to find hanging culverts in Vanua Levu. Hanging culverts are a major barrier to migration of endemic fish from the oceans to upstream areas. Knowledge of hanging culvert locations will help us evaluate threats to biodiversity in the rivers and creeks of the important corridor between Mt. Kasi in the east, and Mt. Navotuvotu in the west. This will help to focus upcoming biodiversity survey effort on the least obstructed rivers which are likely to still be home to healthy populations of endemic fish.

After a 4am start in Suva, work began in as soon as Waisea and I got off the ferry at Nabouwalu, working our way eastwards from there towards Wailevu East in Cakaudrove. Every dusty, bumpy road or track was explored in search of the troublesome culverts. The survey took a total of 5 days to complete, with approximately 280 culverts being mapped, photographed and described. We identified about one third of these as the type of hanging culvert which blocks fish migration routes.

About 98% of Fiji’s freshwater fauna make contact with the sea to complete their lifecycle. So at certain periods in their lives they migrate down to the sea, and ultimately will need to return upstream to complete their lifecycle. These fish are skilled at navigating natural obstacles on their upstream migrations, but unfortunately culverts which hang away from the river surface present an impossible obstacle even for the most intrepid climbers.

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In recent freshwater surveys in Fiji, the presence of hanging culverts correlated with low species diversity and abundance relative to similar areas without hanging culverts, even in areas where the river was surrounded by intact forest. This implicates the hanging culverts as a possible cause of the decline in fish diversity and abundance.

It can be concluded from the culvert survey that most major catchments which have bridges do not have culverts, whilst small creeks do have culverts. This was a promising sign since most of these major catchments therefore run right up to the headwaters without migration barriers. There were also good indications of intact forest within some areas of Wainunu and Dama districts.

This project is kindly supported by the Critical Ecosystem Partnership Fund (CEPF), a joint program of l’Agence Française de Développement, Conservation International, the Global Environment Facility, the Government of Japan, the John D. and Catherine T. MacArthur Foundation, and the World Bank.

First steps to clean drinking water

Well-forested water catchments are the perfect way to manage and maintain drinking water supply. A small group from WCS Fiji last week visited Nadivakarua and Namalata, two villages in Kubulau District, Bua Province, to map out their water sources and assess any environmental threats to the future sustainability of the water source. Protecting the catchment immediately surrounding the water source is the first step to having a reliable source of clean water for the future.

Following the survey, Namalata village has decided to draw a 200 metre radius buffer around their water source where farming and clearing will be prohibited. Currently, farming has crept up to around 50 metres from the water source in places, meaning that the water source is at risk of drying up in a drought. Already, the water source is only a small creek which is a worrying sign.

The survey found a well-forested area around the water source for Nadivakarua village – village elders agree this water source has never dried up, even when some other villages in Kubulau district run short of water during the dry season. Nadivakarua have marked a track around the water source, to make sure that farming doesn’t encroach on the forest near the source. These community decisions will be incorporated into the Kubulau ecosystem-based management plan which is currently being updated as part of an adaptive management process.

Comics Delight Kids

WCS Fiji have just returned from launching a comic book titled “The Adventurers of Joji Goby” at 5 different schools in Kubulau and Wainunu, Bua. The comic is about the life-cycle of Joji a freshwater goby, which hatches in freshwater before migrating to sea as larvae and migrating back as post-larvae. Joji met with a lot of obstacles upon his return journey, on his quest to find his parents. The launch included a puppet show of Joji’s adventure followed by the designation of Goby Youth Ambassadors for each village, who will help with the enforcement of rules in ecosystem-based management plans for the two districts. The comic was created using funds from the Disney Friends for Change Program. You can see more photos of the launch and the very special puppets on the WCS Fiji Facebook page, at www.facebook.com/wcsfijiprogram.