Hindawi Publishing Corporation Journal of Marine Biology Volume 2012, Article ID 721483, 18 pages doi:10.1155/2012/721483 Research Article Modelling Reef Fish Population Responses to Fisheries Restrictions in Marine Protected Areas in the Coral Triangle Divya Varkey,1 Cameron H. Ainsworth,2 and Tony J. Pitcher1 1 Fisheries Center, AERL, University of British Columbia, 2202 Main Mall, Vancouver, BC, Canada V6T1Z4 2 College of Marine Science, University of South Florida, St. Petersburg, FL 33701, USA Correspondence should be addressed to Divya Varkey, d.varkey@fisheries.ubc.ca Received 14 June 2011; Revised 18 October 2011; Accepted 8 November 2011 Academic Editor: Ricardo Serrao˜ Santos Copyright © 2012 Divya Varkey et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Marine ecosystem models are used to investigate marine protected area (MPA) benefits for coral reef ecosystems located in Raja Ampat, in the heart of the Coral Triangle. Field data from an integrated and diverse research project is used to develop a spatial ecosystem model using Ecopath, Ecosim, and Ecospace modelling software. The ecological and fisheries responses of a reef ecosystem to different levels of fishing effort restrictions inside MPAs are explored. The trade-offs of allowing some fisheries to operate inside the MPAs versus designating the MPAs as no-take zones are highlighted. The results show that rapid rebuilding of reef fish populations, especially the large charismatic species, requires no-take areas. Distinct trade-offs in spillover benefits are observed between partially fished and no-take MPAs. 1. Introduction an important role in the ability of the ecosystems to respond to fishing and other stressors [17]. Fishing has A global review of the status of coral reefs found that several resulted in changes to the target and nontarget reef fish coral reef ecosystems have declined; the review suggests communities [18–21]. Local abundances of coral reef fish are that management for status quo is a “weak” goal; rather also determined by the relative magnitudes of larvae recruit- efforts should be made to restore the reefs [1]. Marine ment, colonization by juveniles and adults, predation, and protected areas (MPAs) have been advocated to rebuild competition for refuges [22]. Similar to the changes observed fish populations, mediate habitat damage, and preserve with fishing, recovery is also dependent on the competitive ecosystem biodiversity [2, 3]. Review of empirical results of balance and trophic composition of reef ecosystems [23, 24]. the effects of marine reserves (i.e., no-take MPAs) shows A spatial ecosystem model of the coral reef ecosystem can that on average the density, biomass, diversity, and size of offer insights into the complexity of relationships and suggest organisms are significantly higher inside the reserves [4]. options for management of MPAs. An important question in Marine reserves appeared to promote an increased density designing MPAs for reef ecosystems is what level of fishing of exploitable fishes in reef ecosystems in the Philippines restriction inside MPAs is necessary to obtain increased size [5, 6], the Caribbean [7, 8], and wherever they are adequately and abundance of reef fish species—could some fisheries be implemented and enforced [9]. Modelling studies have also allowed or should MPAs be designated as no-take zones? demonstrated the biomass and spillover enhancing potential And, are the responses similar for all reef fish species? The of reserves [10, 11]. The type of response depends on the objectives of this study are to explore different types of species protected [12–14], location, size, spacing of protected fishing restrictions inside an MPA and the implications for areas [15], growth of tourism, diving operations [16], and (i) resulting rebuilding effect on the fish populations inside other factors. the MPA under full restriction or partial restrictions on Coral reefs are magnificent marine ecosystems; their commercial and destructive fisheries, (ii) fisheries within the incredible species richness and species composition play spillover region and fisheries within the MPA under partial 2 Journal of Marine Biology fishing closures, and (iii) the effect of adjacent (spillover) system [36] that maps the interspecies interactions through fisheries on population dynamics within the MPA. predator-prey linkages. Ecosim is dynamic and allows modelling of species composition changes over time [37, 38]. Ecospace integrates Ecopath and Ecosim across a two 2. Methods dimensional spatially explicit domain [39, 40]. Following is 2.1. Study Area. Raja Ampat, in Eastern Indonesia, is located a brief description of the underlying Raja Ampat Ecopath in the heart of the Coral Triangle (Figure 1). The area and Ecosim model which was used for the Ecospace model encompasses a variety of marine habitats including some of presented here; an extended summary of data sources is the most biodiverse coral reef areas in the world [25, 26]. provided in Appendix A and more detail on data and model It is estimated that Raja Ampat possesses over 75% of the development is documented in technical reports [34, 35]. world’s known coral species [27]. The coral reef ecosystem Functional groups in EwE models are either species or is still relatively intact. A survey across 45 reef sites in species groups that can be aggregated based on feeding guild, 2002 in Raja Ampat revealed that 50% of reef sites were in habitat, body size, or other niche determinants. The Raja “excellent” to “good” condition measured in terms of fish Ampat EwE model has 98 functional groups—57 fish groups diversity, coral diversity, and coral cover, although some form representing 1203 fish species, 22 groups of invertebrates, of stress or damage was observed on 85% of the surveyed 9 groups of mammals, turtles, or birds, 4 groups of sites [28]. The predominant stressors were fishing pres- jellyfish or zooplankton, 4 groups of primary producers, sure (including destructive fishing methods), siltation, and and 2 detritus groups (Table 2). With a limited number of eutrophication/pollution. A decree by the Bupati (Regent) in functional groups, we are forced to limit our representation 2003 declared Raja Ampat a maritime regency “Kabupaten of noncommercial species (e.g., cryptobenthic species which Bahari” [29]; the regency adopted the goal of improving the function predominantly as detritivores and small carnivores welfare and prosperity of human communities by promoting in the reef ecosystem [41]). However, cryptic species are fisheries, conservation, and tourism [30]. Studies of fisher aggregated into functional groups (e.g., small demersal fish perceptions in Raja Ampat showed that the fishers believed and small reef fish), and these functional groups would tend that fish catch had declined over the past 10 to 20 years to partly reflect the cryptic behaviour through vulnerability [31, 32]. Concerned with the issues of fisheries manage- parameters in Ecosim. Commercial importance of species ment and with the intention to develop environmentally and their functional roles were considered in designing sound ecosystem-based policies, the government in 2006 the functional groups in the model—the groups were first set up a network of seven MPAs encompassing 44% of the established based on literature [17, 25] and then revised at a “model coordination workshop” with local scientists and reef area. The Regency government also participated in a ff collaborative project—the Birds Head Seascape Ecosystem- field sta held in 2007 in Sorong, Indonesia. The predator- Based Management (BHS EBM) project—involving three prey interactions between species were described by diet link- environmental NGO partners—Conservation International ages. Stomach content analysis on fish purchased from the (CI), The Nature Conservancy (TNC), and World Wide markets in Sorong was used to inform the diet interactions Fund (WWF)—in a science-based initiative in partnership (source: Christovel Rotinsulu, Conservation International, with local stakeholders and academic partners to explore JL Gunung Arfak. No 45. Sorong, Papua, Indonesia. Email: ecosystem processes relevant to management. Raja Ampat [email protected]). For noncommercial species, a diet ecosystem models were developed as part of this project algorithm was designed based on the FishBase diet table using the Ecopath with Ecosim (EwE) modelling framework [42] and the size of the fish in the functional group. For [33–35]. With respect to marine protected areas, the research invertebrate species, diet information was obtained from a questions explored were identified through discussions with literature review. Reef monitoring SCUBA and snorkeling the Regency fisheries managers and scientific partners work- diving transects on reef sites selected using a stratified ing in Eastern Indonesia. Ecological responses in three of random approach were used to inform the biomass estimates the seven MPAs (Kofiau 328 km2; Southeast Misool 943 km2; for several functional groups and coral coverage in the Dampier Strait 202 km2) are investigated in this paper. model. Biomass for other functional groups was obtained Kofiau is a small island with only a few fishing villages from previous reef surveys in Raja Ampat [43], estimates (Figure 1), Misool is more densely populated island, is closer from literature, and in some cases the EwE model was to the industrial