Western Indian Ocean J. Mar. Sci. Vol. 9, No. 1, pp. 115 - 134, 2010 © 2010 WIOMSA SHORT COMMUNICATION Rapid Visual Assessment of Fish Communities on Selected Reefs in the Bazaruto Archipelago Jade Q. Maggs1, Camilla Floros1, Marcos A.M. Pereira2 and Michael H. Schleyer1 1Oceanographic Research Institute, P.O. Box 10712, Marine Parade, 4056 South Africa; 2Associação para Investigação Costeira e Marinha (AICM), P.O. Box 2046, Maputo, Mozambique. Keywords: Bazaruto Archipelago, Mozambique, ichthyofauna, fish surveys, underwater visual census, coral reefs. Abstract— Rapid visual censuses were conducted of fish on eight coral reefs in the Bazaruto Archipelago, Mozambique, in 2007. SCUBA and snorkelling were used for the censuses in depths between 1-20 m, yielding an inventory of 249 fish species belonging to 50 families. This is intended to serve as a baseline for more detailed studies and monitoring programmes in the future. Although fewer species were recorded relative to other studies conducted in the Western Indian Ocean, the trophic structure on Bazaruto’s reefs proved typical for the region, indicating a relative measure of reef health. However, other regional studies were not directly comparable, differing in habitat, duration of sampling effort and methodology. This highlighted the need for a long-term monitoring programme specifically adapted for the Bazaruto reef types to provide a basis for their sound management and conservation. INTRODUCTION Mozambique in the Western Indian Ocean (WIO). The seas around the The Bazaruto Archipelago consists archipelago are rich in marine life of five islands and is located and provide an important source approximately 20 km off the coast of of protein to the local community Corresponding Author: JQM E-mail: [email protected] 116 J. Q. MAGGS ET AL. (Everett et al., 2008; Reina, 1998). beach seines, gamboa traps and The ecological importance of the spearguns. Mozambican citizens living archipelago first received attention outside the BANP are only allowed in 1971 with three of the islands, to use handlines inside the park and Benguera, Magaruque and Bangue, are allowed to use beach-seines in a receiving national park status (area of small area south of Magaruque. Gill- protection ~600 km2); Bazaruto and netting is prohibited and no industrial Santa Carolina were only designated or semi-industrial fishing operations as ‘special surveillance zones’ (Reina, are allowed in the BANP. The no-take 1998). After many years, the Bazaruto zones are Two-mile Reef, Lighthouse Archipelago National Park (BANP) Reef, Santa Carolina and small rocky was proclaimed in 2001, protecting all outcrops on the inside and outside of five islands. The BANP was extended Bazaruto Island (Fig. 1). However, in 2003 to include the Cabo de São only Two-mile Reef, Lighthouse Sebastião peninsula in the south and Reef and Santa Carolina enjoy strong now covers 1430 km2. Mozambique’s compliance. There are no seasonal Ministry of Tourism is responsible for restrictions on fishing in the BANP management of the BANP. and recreational SCUBA diving and The coral and rocky reefs in the snorkelling is allowed in the no-take archipelago provide habitat for a zones. A new management plan is wealth of biodiversity, making it a being developed for the Park but, at popular tourist destination (Schleyer the time of writing, had not yet been & Celliers 2005). Visiting SCUBA implemented. divers and recreational anglers bring The livelihoods of the local in valuable revenue to the area and, communities depend, to a great extent, although fishing is allowed in the on marine and coastal resources BANP, it is regulated by means (Everett et al., 2008). An increasing of permits and no-take zones. All population characterises many coastal recreational fishing requires a permit communities in the WIO, placing and is mostly boat-based, emanating pressure on such resources (Lindén from a number of resorts scattered et al., 2002). Effective management through the islands. A number of is thus required, the success of which seasonal fishing competitions are depends on monitoring programmes hosted by the various resorts, bringing (Obura et al., 2002). These have been in foreign anglers. seen as a priority in the WIO region The artisanal fishery is the main since the 1998 mass coral bleaching economic activity for more than 70% event (Lindén et al., 2002). Monitoring of the local population (Everett et al., of a resource depends on a thorough 2008). Artisanal fishermen harvest knowledge of the biodiversity of an fish using dhows, pirogues, approved area. Species inventories comprise RAPID VISUAL ASSESSMENT OF FISH COMMUNITIES ON SELECTED BAZARUTO REEFS 117 a fundamental baseline in this MATERIALS AND METHODS regard, providing a foundation for an understanding of ecological processes Study Area and the effects of biodiversity loss The Bazaruto Archipelago is a chain on ecosystem function (Bellwood & of four islands, Bazaruto, Benguera, Hughes 2001; Gillibrand et al., 2007). Magaruque and Bangue, with a fifth Baseline fish community data are island, Santa Carolina, lying on the sparse for the WIO region but those inside of the island chain (Fig. 1). published include fish inventories for The reefs around the archipelago are the Glorieuses Islands (Durville et diverse and include rocky patch reefs, al., 2003), Mayotte (Chabanet, 2002), rocky massifs, fringing and barrier Andavadoaka (Gillibrand et al., 2007), coral reefs and deeply submerged Juan De Nova (Chabanet & Durville coral reefs (Schleyer & Maggs 2008). 2005), Tuléar (Harmelin-Vivien, The fish community assessment was 1979) Geyser and Zéléé (Chabanet et undertaken on all these reef types in al., 2002), Réunion (Chabanet, 1994), depths from 1-20 m. A range of reef Sodwana Bay (Chater et al., 1993; habitats within these reef types was 1995) and Bassas da India (van der sampled with varying coral cover and Elst & Chater 2001). topographic complexity. Pereira (2000) prepared a general Twelve-mile Reef is a submerged checklist of reef-associated fishes for sandstone coral reef roughly twelve Mozambique, Benayahu & Schleyer nautical miles (18 km) north of (1996) and Schleyer & Celliers (2005) Bazaruto’s northern point in the compiled coral inventories for the open sea. It is open to fishing and Bazaruto reefs, Motta et al., (2002) and SCUBA diving but is relatively Rodrigues et al., (2000) quantified fish inaccessible for artisanal fisherman communities at two sites off Bazaruto using traditional pirogues and dhows. and van der Elst & Afonso (2008) However, recreational fishers and compiled a fish inventory based on SCUBA divers, using large boats with work undertaken at Bazaruto in the outboard engines, are able to access late 1980s. However, there appears this reef. Relative to the other reefs to have been no further ichthyofaunal sampled in this study, Twelve-mile research in the Bazaruto Archipelago. Reef lies furthest from the waters This paper, therefore, presents a recent enclosed between the islands and the and more comprehensive inventory mainland. The reef was sampled at of the fish community as a precursor depths between 15-20 m. to further ecological studies on the Tubarão, Garoupa and Kingfish Bazaruto reefs and highlights the need Reefs are sedimented rocky patch for long-term monitoring. reefs which are open to fishing and 118 J. Q. MAGGS ET AL. Fig. 1. Map of the Bazaruto Archipelago, Mozambique. Study sites are indicated by (♦). RAPID VISUAL ASSESSMENT OF FISH COMMUNITIES ON SELECTED BAZARUTO REEFS 119 SCUBA diving. Garoupa lies nine km Data Collection north of Bazaruto and was sampled at Two fish surveys were conducted, one 16-20 m. Tubarão lies 19 km north- in February 2007 and one in November east of Inhassoro and was sampled 2007. Surveys were undertaken in the at 13-18 m. Kingfish Reef is 13.5 km late morning on a low to outgoing east of Inhassoro and was sampled at spring tide. Fish communities 6-11 m. High turbidity is common on were sampled on the reefs using an these reefs. underwater visual census technique Lighthouse Reef is a fringing coral adapted from Samoilys (1997) in reef located on the north-eastern tip of which three divers recorded the Bazaruto. It is a no-take zone and is presence of fish species on slates. closed to fishing (including artisanal A combination of diving methods fishing) but open to SCUBA diving was used with SCUBA being used and snorkelling. Only the inner lagoon for deeper locations and snorkelling was sampled and the depth ranged for shallow inner lagoons. Divers between 1-3 m. conducted a 45 minute timed swim Two-mile Reef is a barrier coral following a random path. Although reef which lies four kilometres the underwater visual census method out to sea between Bazaruto and is known to underestimate small and Benguera Islands. This reef is also a cryptic species, it was employed no-take zone being closed to fishing because it provides a means of (including artisanal fishing). Although sampling the fish community with little fishing is prohibited, Two-mile Reef disturbance (Fowler, 1987; Harmelin- is subjected to diver pressure and Vivien et al., 1985). Identification of anchor damage from visiting small species was confirmed after sampling craft, recreational dive operators and using appropriate reference books tourists. All reef habitats at Two-mile (King, 1996; King & Fraser 2001; Reef were sampled at depths between Lieske & Myers 1999; Smith & 1-18 m. Heemstra 1986). Amphitheatre and Camel’s Hump are submerged rocky massifs located Trophic Categorisation two kilometres seaward of Cabo de Fish species were assigned to one São Sebastião. They are open to fishing of ten trophic categories based on and SCUBA diving but turbidity classifications by Harmelin-Vivien is high on these reefs. Sampling at (1979); Hiatt & Strasberg (1960); Camel’s Hump ranged between 13- Hobson (1974) and Myers (1999) 16 m in depth and at Amphitheatre, as cited by Chabanet & Durville between 14-19 m.