Invasive Species Science, Planning & Stewardship (TNC)

Fish spawning aggregations are extremely important to local ecosystems and economies, but they are not resilient to anything greater than light fishing pressure. In some cases, FSAs have been lost even from subsistence fishing1, which is often considered sustainable2.

The reasons for FSA vulnerability vary, but often it is a result of the predictable nature of FSA formation, and the life history characteristics of many FSA-forming species. Moreover, spawning in FSAs is considered to represent 100% of the total reproductive output for most species studied to date3, such that FSA fishing can have profound effects on populations, often over brief time spans4.

Characteristics of FSA-forming species may include:

• Slow growth rates
• Late sexual maturity
• Small home-range size as adults
• Complex life cycle
• Protogynous hermaphroditism

This module of the Reef Resilience Toolkit focuses mainly on the conservation of Reef Fish Spawning Aggregations (FSAs). Although the problems facing global fisheries are diverse, we have chosen to focus on fish spawning aggregations because of their extreme susceptibility to over-fishing, and their importance as part of the resilience model.

Maintaining healthy breeding populations (seed sources) of reef fish is critical for the sustainability and health of coral reef systems. Fish spawning aggregations are an example of Critical Areas that need special protection and management in order to build resilience into a comprehensive reef management program.

Key Sections of the website include:

• Introduction
• FSA Basics
• Identifying FSAs
• Protection Priorities
• FSA Management
• FSA Monitoring
• Communicating FSAs
• Case Studies
• Resources
  

Four Case Studies are detailed in the ToolKit. Here is some detail on two:

Belize

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In 2001, all of the major governmental and non-governmental organizations working on spawning aggregation monitoring and conservation in Belize formed the National Spawning Aggregations Working Group, which was chaired by The Belize Audubon Society for several years, and now by Friends of Nature. This informal group has worked to validate, monitor and describe 13 multi-species spawning aggregation sites in Belize, and has involved local aggregation fishers in the monitoring and research at these sites. Armed with three years of monitoring data, the group proposed sweeping national legislation to protect endangered Nassau groupers by means of a closed season. The enacted legislation protects all of the viable spawning aggregation sites that are known to harbor multi-species aggregations.

During its initial years of existence, the National Spawning Aggregations Working Group raised the issue of conserving spawning aggregations using a variety of techniques. The Minister of Fisheries visited traditional fishing sites, talked with fishers directly, and came to understand the issues. Various members of the group conducted workshops, developed posters, radio and television spots, infomercials and short videos, and gradually raised the nation’s consciousness on the subject. Fishers were involved in all major research and monitoring, and were paid for their assistance as boat captains and as research assistants. Fishers in the primary communities that exploited the FSAs were also provided training in alternative livelihood activities, such as SCUBA dive guiding, kayaking and fly-fishing. The local fishing cooperatives, which act as the main fish buyers/exporters, support the idea that FSA protection enhances the future of sustainable fisheries, and now actively participate in spawning aggregation protection.

The Nature Conservancy then developed a series of maps that located reef promontory spawning aggregations. These maps were based on the analysis of geo-referenced satellite imagery. Using Tip(gps)">GPS , 13 spawning aggregation sites were mapped into buffer zones of about 6–8 square miles. When presented with these maps in a public forum, the fishers agreed with the concept, but suggested that the size of the aggregation closures be reduced. New maps were created and shared with fishers who agreed to the new boundaries.

Prior to signing the legislation to protect spawning aggregations, the Minister of Fisheries requested that patriarch fishers join him in a public forum, to ensure that he was adequately representing their interests. Each fisher offered support, which prompted the Minister to sign the legislation in November, 2002. The legislation created a closed season for Nassau grouper between December and March, and fully protected 11 new marine reserves surrounding the spawning aggregation sites that were previously established. The signing ceremony took place at a public Fisherman’s Festival, sponsored by TIDE, the Toledo Institute for Development and Environment. TIDE is an important advocate of conservation and local sustainable development, and is involved in the co-management of protected areas in Belize’s southern Toledo District, including Port Honduras Marine Reserve and Payne's Creek National Park.

Principal challenges to the protection of Belizean FSAs include lack of enforcement and lack of funding. Enforcement at all closed sites is not 100 percent effective, as evidenced by fishers’ observations of boats at the FSAs during spawning seasons, and observations of Nassau grouper in the marketplace during spawning months. This is particularly disturbing to the compliant fishers who support the closures and hope to see improvements in the spawning populations. A related problem is a lack of funding for both enforcement and monitoring. Members of the committee note that the lack of funding prevents the above noted problems with enforcement from being addressed fully.

U.S. Virgin Islands

Overfishing is a major concern in the USVI, with approximately 350 licensed commercial fishermen using a variety of gear, including Antillian fish traps, hand lines, gill nets, long lines and seine nets. Trap fishermen deploy over 5000 fish traps throughout the shelf of St. Thomas, St. Croix and St. John, and catch a wide assortment of reef fish (snapper, grouper, grunts, triggerfish, surgeonfish, parrot fish, angelfish, and jacks), most of which are sold at local fish markets and to restaurants. Artisanal and recreational fishing is concentrated mostly along the shoreline or in near-shore waters. It is thought that most fish stocks in the Virgin Islands are overfished, as evidenced by the absence of large predatory species (i.e., snapper and groupers).

The fish spawning aggregation (FSA) monitoring project at Grammanik Bank began as a collaborative effort with the USVI Division of Fish and Wildlife, which provided funding to collect baseline data on an exploited yellowfin grouper spawning aggregation. The information collected included number of fish within the aggregation, size frequency of males and females, location of the spawning sites, and the specific area used by aggregating groupers. Cooperation by local fishermen allowed the search for the spawning aggregation sites to be narrowed. Over two spawning seasons, nearly one hundred hours of visual censuses were completed, using timed swims and scooter surveys. Based on these surveys, the actual spawning site was identified, and initial boundaries for protecting the spawning aggregation site were established. Through monitoring activities, several other species of grouper and snapper (including the endangered Nassau grouper) were discovered to have used the same spawning aggregation site.

The information from this study was compiled in the form of a letter to the Caribbean Fisheries Management Council, and to NOAA’s National Marine Fisheries Service (NMFS), which recommended immediate seasonal closure of the site. Public discussion forums were then initiated to discuss the proposed closure with commercial fishermen, scientists, and management and enforcement agencies (U.S. Fish and Wildlife, Coast Guard, U.S.V.I. Division of Environmental Enforcement). These discussions resulted in three proposed closure boundaries which varied considerably in size, from 100 km2 to 4.5 km2 plus the protection of coral reef habitat of the Grammanik Bank. After a series of meetings, the commercial fishermen rejected the two larger closures (20 km2 and 100 km2) and accepted the smaller closure, due to a lack of scientific data justifying a larger closure and the severe impact it would impose from loss of fishing grounds.

Since the establishment of the Grammanik Bank closure, UVI scientists have continued to monitor yellowfin and Nassau grouper spawning populations, through underwater surveys, catch and release, and conventional tagging programs, with funding from NOAA’s NMFS, Puerto Rico Sea Grant and National Institutes of Health. Currently, acoustic tracking of grouper movements are being used to identify areas occupied during spawning and migratory pathways of yellowfin and Nassau grouper. This information will be used to make recommendations to management agencies and commercial fishermen for altered boundaries.

Since the closure of the FSA, the number of groupers and other species that occupy the spawning aggregation site during the spawning season have increased. Prohibiting fishing has allowed populations to increase, and spawning to take place undisturbed. The issue of the FSA closure has motivated fishermen to organize and take an active role in fisheries management. This resulted in the formation of the St. Thomas Fishermen’s Association, who hold fund raisers so that they can attend Caribbean Fisheries Management Council meetings, as well as publish a quarterly newsletter (The Olewife). Another closure, the Red Hind Bank Marine Conservation District (MCD), has been extremely successful in rebuilding the spawning population of red hind, and has resulted in fishermen catching greater numbers and larger sizes of red hind in surrounding areas. This positive impact of a fishery closure makes more fishermen receptive to MPAs as a viable management option.