Observations on fisheries activities at Navassa Island

Marine Fisheries Review, Summer, 2003 by M.W. Miller, D.B. McClellan, C. Begin

Introduction

Despite extremely high rates of primary production in coral reef ecosystems, actual yield of coral reef fisheries is relatively low. In addition, the ecological complexity, richness, and specialized life histories of coral reef organisms and communities make them particularly susceptible to overexploitation (Birkeland, 1997). Results of such overexploitation in Caribbean islands are seen in the documented drastic declines in catch-per-unit-effort, size structure, and/or species shifts in the fisheries of Jamaica, Grenada, the U.S. Virgin Islands, and others (Koslow et al., 1988; Jeffery, 2000; Rogers and Beets, 2001). Indeed, subsistence fishing to support a single family has been described as impacting target populations on the scale of a whole bay in the U.S. Virgin Islands (Coblentz, 1997).

Navassa Island is small and, although claimed by the United States as part of the Caribbean Islands National Wildlife Refuge, sovereignty is disputed by Haiti. Due to its isolation, uninhabited status (except for temporary squatters), and some preliminary quantitative visual fish census work, Navassa Island has been described as displaying a relatively pristine reef community (Anonymous, 2000; Grace et al., 2000; Miller and Gerstner, 2002). However, this interpretation has also been questioned due to the observation of ongoing fishing activity by migrant Haitians, the complete lack of quantitative information regarding the intensity of this fishing activity, and the potential for its rapid escalation (Collette et al., 2003: Grace et al., 2000; Miller and Gerstner, 2002)

Navassa Island is about 5 [km.sup.2] in area and is comprised of a raised plateau surrounded by cliffs which reach down to a submarine terrace at 23-30 m depth (Fig. 1). The primary fishery habitats are reef walls formed by the cliffs and large boulders (or "calves" as analogous to the chunks that fall off of icebergs) that have been dislodged from the cliffs, scattered patch reefs and hardbottom areas on the 25-30 m terrace, and deeper reef slopes and shelves (>30 m) farther offshore that have not been well described.

[FIGURE 1 OMITTED]

Navassa Island's oceanic position in the Windward Passage (Fig. 1) exposes it to substantial physical energy. The east coast, particularly, bears the brunt of persistent swells, regular storms, and hurricanes. Inshore and backreef habitats, which are important in the life history of several reef fish groups, are largely absent.

Despite its status as a National Wildlife Refuge, fisheries at Navassa Island are effectively unmanaged as regulations are not well publicized and enforcement is non-existent due to Navassa's remote location, surrounded by international jurisdictions. Fishing activities are undertaken by migrant Haitian artisanal fishermen, and these activities appear to have been ongoing since at least the 1970's. Anecdotal observations from a previous NMFS expedition (1) reported five Haitians fishing out of a 4.3 m sailboat along the north/northwest coast and "catching only small grunts [Haemulidae] and one small barracuda [Sphyraena barracuda]". Other anecdotal accounts suggest that some technological escalation in this fishery had occurred between scientific expeditions which had occurred in 1997 and 2000. That is, no motors were observed in 1997, while all the vessels observed during the 2000 expedition had 10-15 h.p. motors (Anonymous, 2000: Miller (2)).

Quantification of catch or effort has not been undertaken for the Navassa Island fisheries, though 0-4 small boats per day were observed employing trap and handline fishing during the 2000 expedition (Miller and Gerstner, 2002). Because of this complete lack of quantitative fisheries information and inadequate quantification of reef fish status (particularly in the recent past), the impact of these ongoing subsistence fisheries is difficult to assess. Underwater visual transect census conducted in the western nearshore reef habitats (<20 m) in 2000 reported moderate to high density of large reef fishes (including larger species of Lutjanidae, Serranidae, and Scaridae), suggesting minimal fishery impact in these nearshore habitats (Miller and Gerstner, 2002) though other reports suggest that large fishes had already been greatly reduced at least in the northwest (Collette et al., 2003). Miller and Gerstner (2002) also suggested that strong socioeconomic "push" factors in Haiti made it likely that fishing intensity and impact at Navassa would increase, possibly rapidly. It is well known that reef communities can be readily overfished (Coblenz, 1997).

There are many definitions of overfishing, most of which cannot be evaluated in the absence of quantitative fisheries statistics (e.g. growth overfishing, Malthusian overfishing). However, qualitative fisheries information can be suggestive of patterns indicating, for example, serial overfishing, (i.e. a progression where the largest and most vulnerable species are removed first, followed by shifts to smaller, less-desirable targets as each group is depleted). For Navassa Island, such qualitative observations are all that are available, and the following observations are offered as indicative of such a pattern.

Methods

Observations were made at Navassa from 29 October to 8 November 2002 based aboard the R/V Coral Reef II (Research Vessel of the John G. Shedd Aquarium, Chicago IL). The primary objective of the expedition was the assessment of reef condition (both benthic and fish assemblages (Miller, 2003)). Fishery observations were opportunistic, and each day, note was made of how many fishing boats were present around the island. In addition, direct interviews and observations were made with three different boats on different occasions. A small (~15 ft) boat from the R/V Coral Reef II was used to approach the Haitian fishing boats and engage the occupants in conversation. The interviews were conducted in French and designed to obtain information directly from the fishermen on their fishing practices and catch. Also, the interviews afforded an opportunity to observe the catch directly (species and approximate amounts and sizes) that was visible in each boat, though thorough unpacking or exact measurements were not undertaken.