Benthic status of near-shore fishing grounds in the central Philippines and associated seahorse densities J.E. Marcus a, * , M.A. Samoilys b,d , J.J. Meeuwig b,e , Z.A.D. Villongco c , A.C.J. Vincent a a Project Seahorse, Fisheries Centre, University of British Columbia, 2202 Main Mall, Vancouver, BC, Canada V6T 1Z4 b Project Seahorse, Zoological Society of London, Regent’s Park, London NWI 4RY, United Kingdom c Project Seahorse Foundation for Marine Conservation, Gaviola Compound, Maria Theresa Village II, Guadalupe, Cebu City 6000, Philippines d IUCN-Eastern Africa Regional Office, P.O. Box 68200, Nairobi, Kenya e School of Plant Biology, M090, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia Abstract Benthic status of 28 near-shore, artisanal, coral reef fishing grounds in the central Philippines was assessed (2000–2002) together with surveys of the seahorse, Hippocampus comes. Our measures of benthic quality and seahorse densities reveal some of the most degraded coral reefs in the world. Abiotic structure dominated the fishing grounds: 69% of the benthos comprised rubble (32%), sand/silt (28%) and dead coral (9%). Predominant biotic structure included live coral (12%) and Sargassum (11%). Rubble cover increased with increas- ing distance from municipal enforcement centers and coincided with substantial blast fishing in this region of the Philippines. Over 2 years, we measured a significant decrease in benthic ‘heterogeneity’ and a 16% increase in rubble cover. Poor benthic quality was con- comitant with extremely low seahorse densities (524 fish per km 2 ). Spatial management, such as marine reserves, may help to minimize habitat damage and to rebuild depleted populations of seahorses and other reef fauna. Ó 2007 Elsevier Ltd. All rights reserved. Keywords: Philippines; Coral reefs; Fishing grounds; Hippocampus comes; Destructive fishing; Benthic condition 1. Introduction Widespread deterioration of coral reefs (Bellwood et al., 2004; Wilkinson, 2004), and the significant contribution of reef fisheries to the nutrition and livelihoods of coastal communities in many developing countries (Polunin and Roberts, 1996; Burke et al., 2002), have created a need to document coral reef status and understand its impact on the associated fish assemblages. The status or ‘‘quality’’ of coral reefs is typically measured in terms of attributes that are widely acknowledged as desirable, such as high live coral cover, low dead coral and rubble cover, low macroal- gal cover and high structural complexity (e.g. Gomez et al., 1994; DeVantier et al., 1998; Jameson et al., 1999). Reefs influence associated species through a host of mechanisms, such as the creation of space and attachment sites, the enhancement of food supply and the provision of refuges from predation (Bruno and Bertness, 2001). There is abun- dant evidence that reef fish are affected by reef quality: a positive correlation between the percentage of hard coral cover and/or the complexity of the benthic substratum and the diversity and abundance of reef fishes is frequently reported (e.g. Hiatt and Strasburg, 1960; Reese, 1977; Talbot et al., 1978; Hixon, 1993; Syms and Jones, 2000; McClanahan and Arthur, 2001; Jones et al., 2004), though the relationships are complex (Roberts and Ormond, 1987; Hourigan et al., 1988). The many natural and anthropogenic factors contribut- ing to degradation of coral reefs include destructive storms, disease, bleaching events, sedimentation, mining and poor fishing practices. Storms can reduce hard coral cover (Gardner et al., 2005) and diseases can be important causes of reef decline (Weil et al., 2006). Bleaching events are 0025-326X/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.marpolbul.2007.04.011 * Corresponding author. Fax: +1 604 827 5199. E-mail address: j.marcus@fisheries.ubc.ca (J.E. Marcus). www.elsevier.com/locate/marpolbul Marine Pollution Bulletin 54 (2007) 1483–1494