Marine Atlas: Maximizing Benefits for Fiji

TRAVELLERS OR HOMEBODIES: MARINE SPECIES RICHNESS Fiji’s marine environment hosts two types of animals: pelagic species and benthic species, both of which are impor- tant and biologically interconnected.

Pelagic species are those that live in the wa- ter column away from the sea floor and coast. Often these species migrate across vast areas of ocean, driven by oceanic conditions and season- al 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 distances, benthic species are often associated with spe- cific sea-floor features and are either attached to the substrate or very site-specific. Both pelagic and benthic species contribute to Fiji’s rich marine biodiversity, are part of complex food chains, and form important habitats. Further- more, many commercially important species of both types are found in Fiji’s waters. Commercially important pelagic species include several species of tuna, such as albacore ( Thunnus alalunga ), bigeye ( Thunnus obesus ), skipjack ( Katsuwonus

pelamis ) and yellowfin ( Thunnus albacares ) tuna, and several important commercial billfish species, such as blue marlin ( Makaira nigricans ), black mar- lin ( Makaira indica ) and swordfish ( Xiphias gladius ). There are also some pelagic shark species, in- cluding the blue shark ( Prionace glauca ), oceanic whitetip ( Carcharhinus longimanus ), shortfin mako shark ( Isurus oxyrinchus ) and silky shark ( Car- charhinus falciformis ). Other sharks such as bull ( Carcharhinus leucas ) or tiger ( Galeocerdo cuvier ) sharks attract countless dive tourists and revenue to Fiji (see also chapter “Beyond the beach”). 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 important consideration for marine management and conservation planning.

Pelagic or benthic?

Some marine species move from one place to another, while others tend to stay in the same location. These species are described as either “pelagic” or “benthic” (see also chapter “Still waters run deep”).

As for Fiji’s numerous benthic species, many invertebrates (those without a backbone) are found in soft sediment habitats. According to its 2016 National Biodiversity Strategies and Action Plan, Fiji has numerous marine invertebrates, including 342 species of hard corals, 760 species of bivalves (such as oysters and mussels) and gastropods (such as snails and slugs), 26 crusta- ceans (such as crabs, lobsters and shrimps) and many echinoderm species (including starfish, sea urchins, and sea cucumbers). Sea cucumbers are particularly important to Fiji, with at least 28 species harvested commercially (see graphic and chapter “Small fish, big importance”). Many ben- thic species form habitats in Fiji’s shallow waters, including corals, seagrass, mangroves 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 compo- sition, nor does it identify whether there are rare

PELAGIC MARINE SPECIES RICHNESS (number of species)

1 - 20 21 - 30 31 - 45 46 - 60 61 - 75 76 - 85 86 - 100 101 - 115 116 - 129

Fiji Provisional EEZ Boundary Archipelagic Baseline

100 50

200 km

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

MAXIMIZING BENEFITS FOR FIJI

HABITAT VALUES

30