Marine Atlas: Maximizing Benefits for Kiribati

TRAVELLERS OR HOMEBODIES: MARINE SPECIES RICHNESS

Kiribati’s marine environment hosts two types of animals: pelagic species and benthic species, both of which are important and biologically interconnected.

Pelagic species are those that live in the water column away from the sea floor and coast. Often these species migrate across vast areas of ocean, driven by oceanic conditions and seasonal food availability (see also chapter “Go with the flow”). On the other hand, benthic species are those that live on or close to the sea floor. Unlike pelagic species, which migrate large dis- tances, benthic species are often associ- ated with specific sea-floor features and are either attached to the substrate or very site-specific.

Both pelagic and benthic species contrib- ute to Kiribati’s rich marine biodiversity, are part of complex food chains, and form important habitats. Furthermore, many commercially important species of both types are found in Kiribati’s waters. Com- mercially important pelagic species include several species of tuna, such as alba- core ( Thunnus alalunga ), bigeye ( Thunnus obesus ) and yellowfin ( Thunnus albacares ) tuna, and several important commercial billfish species, such as blue marlin ( Makai- ra nigricans ), black marlin ( Makaira indica )

and swordfish ( Xiphias gladius ). There are also some pelagic shark species, which are now protected by the world’s sec- ond largest shark sanctuary and a ban on commercial shark fishing within the entire Kiribati EEZ. Pelagic species also include the smaller species that support these large commercially important species (see also chapter “Fishing in the dark”). The routes these species take to migrate, and thus the connectivity of their habitats, are an impor- tant consideration for marine management and conservation planning.

As for Kiribati’s numerous benthic species, many invertebrates (those without a back- bone) are found in soft sediment habitats. According to the Ocean Biogeographic Information System, Kiribati has at least 84 species of corals, 68 species of bivalves (such as oysters and mussels) and 261 species of gastropods (such as snails and slugs), 300 species of crustaceans (such as crabs, lobsters and shrimps) and 68 spe- cies of echinoderms (including starfish, sea urchins and sea cucumbers). Many benthic species form habitats in Kiribati’s shallow

waters, including corals, seagrass, man- groves and algae (see also chapter “Home, sweet home”). In general, species richness can be used as an indicator of conservation significance. It does not, however, provide information on species composition, nor does it identify whether there are rare or priority species in an area. Further, areas with similar species richness may have very different species present, which would affect the conserva- tion and management measures required.

5°N

PELAGIC MARINE SPECIES RICHNESS (number of species)

5°N

1 - 23 23 - 41 41 - 61 61 - 79 79 - 93 93 - 103 103 - 112 112 - 129

0°

Kiribati Provisional EEZ Boundary

200 100

400 km

0°

Copyright © MACBIO Map produced by GRID-Arendal Sources : Becker et al, 2009; Claus et al, 2016; Kaschner et al, 2016; Smith and Sandwell, 1997.

5°S

170°E

175°E

180°

175°W

170°W

5°S

0°

10°S

5°S

160°W

155°W

150°W

MAXIMIZING BENEFITS FOR KIRIBATI

OCEAN VALUES

26