A. The Need for Conservation

Spawning aggregations are predictable in time and space and are particularly vulnerable to fishing. Moreover, many of the more vulnerable reef fish species (i.e., long lived, late maturing) are the ones that aggregate to spawn and are also particularly valued for food. The World Conservation Union (IUCN) Red List of Threatened Species includes a number of reef species that aggregate to spawn; several are presently listed as endangered or vulnerable, or are being considered for such a listing by the IUCN (http://www.redlist.org). These include the Nassau grouper (Epinephelus striatus), the humphead wrasse (Cheilinus undulatus), and several other groupers. Their inclusion in the Red List has much to do with their tendency to form spawning aggregations that are targeted by fishermen. In the Indo-Pacific, threatened or vulnerable species have been listed largely because of declines associated with demand for them in the Live Reef Fish Trade (LRFT). The LRFT is discussed below.

Most effort going into studying reef fish spawning aggregations is focused ultimately on their preservation through complete protection or management. Intelligent conservation decisions require good biological knowledge. Although it would be shortsighted to attempt to plan detailed conservation and management initiatives without the appropriate scientific underpinning, we do already understand enough to know that all exploited aggregations must be protected or managed in some way, otherwise there is a good chance that they will decline and ultimately cease to form. With very few exceptions, it is non-precautionary to exploit spawning aggregations that are not managed.To fine-tune conservation and management measures, however, to ensure the best possible protection, solid knowledge regarding the timing, duration, location, migration distances, physical oceanography of sites, and other aspects of spawning aggregations are essential, knowledge to be gained through sound science.

So, should aggregations be fished at all? Although aggregations have been exploited for long periods at very low levels of fishing in the past, and although there are sizeable social and economic incentives to continue to exploit spawning aggregations, we do not know what are sustainable levels of exploitation for any aggregation. Most importantly, it is patently clear that aggregations can not withstand modern levels of fishing pressure or modern techniques of fishing. Until we understand more about aggregation dynamics and the effects of the total sum of fishing pressure on a species both on their spawning aggregations as well as at non-aggregating times, the literature and experiences elsewhere strongly suggest that unmanaged aggregations should not be fished at all. All aggregations that are being monitored are showing probable decreases in abundance of fish, increasing bias in sex ratios (e.g., Koenig et al., 1996) or other changes, although unfortunately relatively few are currently being monitored over the long term, or in a consistent and standardized way.

If aggregation sites are known, it might be feasible to close only the aggregation sites to fishing with no other management measures needed. However, this does little to protect fish that might be migrating to the site (e.g., lane snapper, Lutjanus synagris; Claro et al., 2001), or fish occurring at an aggregation that is not widely known. In such cases, a seasonal closure on the species may be appropriate, so that all aggregation sites (known and unknown) are protected. In some extreme cases, where a species does aggregate to spawn but overall its populations are under heavy fishing pressure, it might be advisable to close the entire species to exploitation. This was the case for the goliath grouper (jewfish), Epinephelus itajara, in Florida, where in 1990 the species was declared a no-take fish. Incidental fish caught on hook and line had to be released. For possible management options other than seasonal and spatial closures see Domeier et al., (2002).

In some locations regulations have been put in place that have not fulfilled their objectives due to insufficient scientific information. In Palau, western Pacific, a closed season was initially instituted for various groupers, extending from April through the end of July. Subsequent observations of aggregation presence indicated, however, that these fishes continued to aggregate until at least the end of August, leaving them open to fishing during a portion of their aggregation period (Johannes et al., 1999).

Rhodes (1999) detailed a number of management steps that were taken in Pohnpei (Federated States of Micronesia) to modify existing regulations protecting grouper aggregation after a survey indicated they were not adequately protecting the aggregations. This sort of active revision of regulations in light of new biological information is important for any management program. In the case of Pohnpei, various fishers were able to access much of the total aggregation legally (up to one third of the aggregation in 1999) at times and locations outside of those protected by regulations (Rhodes, 1999).

Such examples illustrate the importance of having sound information on which to base management action if it to fulfill its intended protection effectively. They also illustrate why regulations always need to be open for amendment, to continually improve protection and management initiatives as new information becomes available or as new markets, and hence new pressures, open up.

Figure 55. This male humphead wrasse, Cheilinus undulatus, is a prime target for the Live Reef Fish Trade (PLC).

The Live Reef Fish Trade (LRFT) represents a relatively new and heavy pressure on reef fish resources of the Indo-Pacific (Fig. 55). Prior to its emergence, fishing on aggregations was limited to subsistence and modest freezing or export levels. However the LRFT has been growing steadily since the early 1990s and is now big business, currently worth over a billion US$ annually (Sadovy and Vincent, 2002). The LRFT involves the capture of a relatively small number of reef fish species, predominantly groupers, that are maintained alive until they reach

Figure 56. A large humphead wrasse, Cheilinus undulatus, freshly dead on a sidewalk in Hong Kong. Taken from a coral reef somewhere in the vast Indo-Pacific, shipped alive from the point of capture to Hong Kong, held in a tank until someone willing to pay the premium price (sometimes>US$100 a kg), then dispatched and quickly cooked and eaten as a special meal to impress business clients or celebrate special events, the Live Reef Fish Trade threatens survival of fishes such as these in many parts of their ranges (PLC).

demand centers such as Hong Kong and mainland China where they are sold as food. Consumers are prepared to pay a premium price for these fish and so business can be extremely lucrative for traders and importers. As wealth increases in China, so demand for these live fish is predicted to increase (Fig. 56). There is growing evidence that fishers and traders are looking to source live reef fish at spawning aggregations for these are lucrative and efficient to target. In most places in the Indo-Pacific there is no management of spawning aggregations at all, and, given the high demand for live fish and the large size of the live fish transporter vessels (Fig. 57), large numbers of fish are likely to be removed if a spawning aggregation should be targeted (Fig 58). Indeed, there are already several examples where aggregations have been fished out as a result of being targeted for live fish. Moreover, mortality of fish removed from aggregations can be high maybe because they are stressed at this time (Johannes, 1997; Johannes et al., 1999; Johannes and Lam, 1999). Aggregations should not be targeted for the LRFT.

Mapstone et al. (2001) felt that Plectropomus leopardus populations were at relatively low risk from targeted harvesting for the live reef fish trade because of the small size of its spawning aggregations, their scattered locations and the limited percentage of the total population present at aggregations at any given time. They felt, however, that species with larger, more predictable aggregations may be more vulnerable to fishing pressure on aggregations.

Ideally conservation organizations and fishery management authorities should adopt and promote the concept that reef fish aggregations should be protected from nearly all direct fishing effort, at least as a precautionary position in the absence of effective management and appropriate biological information. Aggregating fishes are often easily disturbed and until we have a clear understanding of the effects that fishing (and other human) activities have on reproduction, we need to reduce overall fishing effort. This requires, at the minimum, that all known aggregation sites not effectively managed already be protected and/or that all relevant species are not fished during their reproductive season(s). Concepts, such as "pulse fishing" (Graham 2001) or other more complex forms of exploitation that require tight compliance and heavy enforcement are unlikely to be feasible in most fisheries and may, instead, be detrimental to aggregations overall.