Contents lists available at ScienceDirect Marine Pollution Bulletin journal homepage: www.elsevier.com/locate/marpolbul Over a decade monitoring Fiji's seagrass condition demonstrates resilience to anthropogenic pressures and extreme climate events Len J. McKenzie a,b, ⁎ , Rudi L. Yoshida a,c a Centre for Tropical Water and Aquatic Ecosystem Research (TropWATER), James Cook University, Cairns, Qld 4870, Australia b Seagrass-Watch, Cairns, Qld 4870, Australia c SeagrassFutures Fiji, Ma'afu St, Suva, Fiji ARTICLE INFO Keywords: Seagrass Habitats Threats Resilience Monitoring Management ABSTRACT Seagrass are an important marine ecosystem of the Fiji Islands. We confirm six seagrass species from the ar- chipelago and defined five broad categories of seagrass habitat. We report, with high confidence, seagrass meadows covering 59.19 km 2 of Fiji's shallow water habitats from literature and this study. Long-term mon- itoring of seagrass abundance, species composition, and seed banks at eight sentinel sites, found no long-term trends. Examination of key attributes that affect seagrass resilience identified meadows as predominately en- during and dominated by opportunistic species which had moderate physiological resistance, and high recovery capacity. We examined threats to Fiji's seagrass meadows from extreme climatic events and anthropogenic ac- tivities using a suite of indicators, identifying water quality as a major pressure. Based on these findings, we assessed existing protections in Fiji afforded to seagrass and their services. This understanding will help to better manage for seagrass resilience and focus future seagrass research in Fiji. 1. Introduction Seagrasses are marine flowering plants that grow in the intertidal and shallow subtidal marine waters of sheltered near-shore environ- ments throughout the Fiji Islands (McKenzie and Yoshida, 2007). As a foundation species for marine biodiversity, seagrasses (locally known as veivutia or co ni waitui) play a supporting role in fisheries production and contribute significantly to the wellbeing of Fijians through their provision of food and a source of livelihoods (Butler, 1983; Choy, 1982; Cullen-Unsworth and Unsworth, 2013; Cullen-Unsworth et al., 2014; Richards et al., 1994). Seagrasses play a critical role in coastal eco- system dynamics, such as coastal protection by stabilizing sediments and sediment accretion (Gacia et al., 2003; Madsen et al., 2001). Sea- grasses also produce natural biocides and improve water quality by controlling pathogenic bacteria to the benefit of humans, fishes, and marine invertebrates such as coral (Lamb et al., 2017). Nutrient cycling in seagrass meadows makes them one of the most economically valu- able ecosystems in the world (Costanza et al., 1997), and the retention of carbon within their sediments contributes significantly to Blue Carbon sequestration (Duarte and Krause-Jensen, 2017; Fourqurean et al., 2012; Macreadie et al., 2017; Unsworth et al., 2012). Fiji's seagrasses are also a significant resource for green turtles in the central south Pacific region (Craig et al., 2004; Piovano et al., 2020) and the primary food for the occasional dugong (Hill-Lewenilovo et al., 2018). These non-reef habitats are particularly important to the main- tenance and regeneration of populations of reef fish such as Emperor fish (Lethrinus spp) (Cullen-Unsworth et al., 2014; Richards et al., 1994; Unsworth et al., 2009), with much of the connectivity in reef ecosys- tems dependant on intact and healthy non-reef habitats (Waycott et al., 2011). In addition, the incorporation of carbon within seagrass tissues can affect local pH and increase calcification of coral reefs, thereby mitigating the effects of ocean acidification affecting coral reefs (Fourqurean et al., 2012; Unsworth et al., 2012). The ecosystem ser- vices provided by seagrasses therefore make them a high conservation priority (Cullen-Unsworth and Unsworth, 2013; Unsworth et al., 2019). Despite being economically valuable (Costanza et al., 1997; Costanza et al., 2014), little is known of the status of Fiji's seagrass resources, which are likely under increasing threats from anthropogenic activities and global climate change (Waycott et al., 2009; Waycott et al., 2011). Local threats include coastal development, inappropriate methods of solid waste disposal, sewage pollution, and siltation of coastal areas as a result of agriculture, forestry and mining runoff (McKenzie and Yoshida, 2007; Singh, 2019; Vuki et al., 2000). These pressures are further exacerbated by global pressures related to climate change, such as increasing cyclone incidence/strength and alterations to rainfall, temperature and light levels (Cullen-Unsworth and https://doi.org/10.1016/j.marpolbul.2020.111636 Received 20 March 2020; Received in revised form 30 August 2020; Accepted 31 August 2020 ⁎ Corresponding author at: Seagrass-Watch, Cairns, Qld 4870, Australia. E-mail address: Len.McKenzie@jcu.edu.au (L.J. McKenzie).