NATIONAL PARK SERVICE Research in the Parks NPS Symposium Series No. 1

In the years following 1934, when submerged marine lands were included within Everglades National Park, the marine resources responsibility of the National Park Service (NPS) has expanded rapidly, now including hundreds of thousands of acres of submerged and coastal lands in eight national seashores and seven national parks and monuments. An additional 30 units of the Service, including large areas in Alaska and Hawaii, Washington State, California, and Maine, are located along, and intimately related to, submerged marine lands. With the inclusion of these areas in the park system, there has evolved an interest in research and management of the full range of marine ecosystems—invertebrate benthic and planktonic communities and intertidal associations—as well as the fisheries. With SCUBA, snorkeling gear, and other viewing devices, it is now common practice to confront underwater systems visually and directly. Such confrontation has brought increasing awareness by visitor and park manager alike that these habitats, like those on land, deserve preservation and enjoyment intact, not merely as what remains following policies of fisheries exploitation.

The following paper briefly traces the evolution of marine research and management activities in one of these marine areas—Virgin Islands National Park, on the island of St. John, in the U.S. Virgin Islands. I believe that the research which the National Park Service has supported there reflects a general Service-wide interest in a comprehensive understanding of the marine habitats within its jurisdiction, and an increased awareness that marine environments are often intolerant of excessive change.

The northern Virgin Islands, including St. John, are centered at about 18°30'N, 64°30'W. Geologically a part of the Greater Antilles, like Puerto Rico just 100 km to the west, the principal islands of the group are typically low and mountainous with altitudes of less than 500 m, of mixed sedimentary and volcanic origins. Receiving 100-150 cm of rain each year, they are clothed with mixtures of moist deciduous forest and dry, wind-adapted scrub and cactus. Sea surface temperatures are consistently above 20°C and the shallow coastal waters support a moderately diverse assemblage of reef-building corals (30+ species) and alcyonarians (45+ species) as well as extensive areas of coarse, clean sand and productive turtle grass beds.

Although the terrestrial boundaries of Virgin Islands National Park were authorized in 1956, submerged lands adjacent to the park were not incorporated until 1962. During that interval, the Service, recognizing the importance of an inventory of the submerged resources, participated in a 2.5-year marine biological and fisheries survey of the waters of St. John. The project's principal investigator was John Randall, now of the Bishop Museum in Hawaii. Others involved included staff from the Virgin Islands Government, Bureau of Sport Fisheries and Wildlife, National Science Foundation, and the Marine Laboratory of the University of Miami. These workers produced a remarkable series of maps and scientific publications on the distribution of shallow habitat types (Kumpf and Randall 1961), the sport fishery, fish food habits, shellfish ecology (Randall 1964), and the systematics of Caribbean reef fishes (Randall 1968). It was primarily from observations on St. John that Randall derived his hypothesis that the bare sand band commonly separating reefs from adjacent grass beds is due in certain areas to the grazing of herbivorous reef fishes who venture only a short distance from the protection of the reef (Randall 1965).

With a biological inventory at hand, the potential park value of the waters of St. John and of Buck Island off St. Croix were readily recognized by the Territorial and Federal governments, resulting in formal designation of these areas as underwater reserves within the National Park System.

In 1966, in response to a request by local college and government research interests, Virgin Islands National Park entered into a cooperative agreement for the establishment of an ecological field station within the park. Lameshur Bay, on the southern shore of St. John, was selected as the site of the Virgin Islands Ecological Research Station. During the station's 8-year history, staff and visiting workers have undertaken a diversity of projects with park approval and support, including a number of research problems of special interest to park resource management. These range from an analysis of local fishing practices and intensity and the repopulation dynamics of overfished reefs (Dammann 1969) to a better understanding of the ciguatera fish-poisoning problem (Dammann 1970). The Service is continuing to work closely with the research station in order to stimulate further basic and management oriented research in both terrestrial and marine subjects.

In 1969 the Virgin Islands (specifically Lameshur Bay on the southern shore of the park on St. John) were selected as the site for an ambitious man-in-the-sea project called "Tektite I." Although directed by the Office of Naval Research, other agencies including the Department of the Interior, National Aeronautics and Space Administration, and the General Electric Corporation participated. In Tektite I, four Department of the Interior aquanaut-scientists spent 60 consecutive days on a 16 m-deep reef in Lameshur Bay in an underwater habitat (Pauli and Cole 1970). In a subsequent return in 1970, 11 teams totaling 55 highly qualified geologists, oceanographers, marine biologists, animal behaviorists, and habitat engineers spent a combined total of 6 months living and working out of the same structure. Projects undertaken from the habitat were selected for their potential contribution to a better understanding of local marine natural history, fish behavior, reef structure, and geologic history (Clifton et al. 1970; Miller et al. 1971; Collette and Earle 1972). The National Park Service, especially in the 1970 Tektite II operation, was an active contributor to the program, providing personnel support, services, and direct contributions in excess of $100,000. Of particular interest was the spiny lobster (Panulirus argus) investigation, begun in Tektite and continued from the research station facilities for an additional 6 months. Through tagging and sonic tracking, considerable information of management value to the park is now available on population-limiting factors, growth, mortality, and movements of local spiny lobsters, plus a reasonable estimate of island-wide abundance (Olsen et al., 1971).

In 1970 the Service was able to assign a full-time research biologist to the Virgin Islands, whose responsibilities include marine and terrestrial research in Virgin Islands National Park and Buck Island Reef National Monument. In that position it has been my function to serve as liaison with the research station, with the Tektite project, and to develop a reasonable, long-term set of research goals and resource management plans.

In conjunction with local park staff and personnel in the Office of the Chief Scientist, a resources management plan (Robinson 1971) has been prepared which sets priorities on various projects and aids in efficient programming of needed funds. Since a number of natural resource problems encountered in Virgin Islands National Park are peculiar to marine parks, these are briefly described in the remainder of this report.

CONSUMPTIVE USES

Special regulations allow limited sport and domestic fishing within park waters. Seining and spearfishing are prohibited, but a substantial amount of fishing continues by trapping, using single-entry, fine wire mesh traps of a traditional Caribbean design. Since these traps are usually placed adjacent to reef structures, they tend to trap selectively the common and frequently territorial reef species. The effect of this trapping on the composition, density, and territorial dynamics of the general reef fish population is still poorly understood. Observations made during one of the Tektite II missions (High and Beardsley 1971) and a long-term investigation by workers at the University of the West Indies, Jamaica (Munro et al. 1970), have provided some data necessary for a reevaluation of fishing practices in the park. Particular attention has been focused on the fineness of the mesh used and the effects of lost traps which continue to fish for extended periods.

VISITOR IMPACT ON CORAL REEFS

With greater numbers of park visitors actually entering the marine environment with SCUBA and snorkeling gear, there is increasing opportunity for physical damage to reef structures. There is also a potential for alteration in reef fish behavior and dynamics which is very difficult to assess. These problems are particularly acute in areas which may have been set aside and appropriately marked as underwater nature trails, and which consequently receive a heavy concentration of visitors.

Two such underwater trails were set up in park waters in the Virgin Islands in the early 1960s. At the time the trails were first established, visitation was low, and unfortunately little attempt was made to document the initial condition of the area. It quickly became apparent that indiscriminate anchoring by visiting boats was a serious cause of breakage, and mooring buoys were installed to control boat access. A program has now been implemented to accurately map and survey each trail area periodically to monitor visitor impact. It has become obvious that we need to know considerably more about natural reef changes in order to distinguish the effects of visitor impact from natural factors—for instance, periodic influxes of bottom sand may destroy large areas, and reexpose old basement reefs; heavy siltation associated with landslides or land-derived erosion may cause die-off on horizontal surfaces. Violent wave action can devastate whole sections of reef, the extreme situation being a hurricane, where whole reefs and other benthic systems may be extensively modified (Glynn et al. 1964).

As one means of determining recovery rates of disturbed areas, NPS is continuing to monitor the hard and soft coral growth on an 11-year-old artificial reef on a sandy bottom in Little Lameshur Bay. Growing conditions there are not ideal, since the reef is subjected to some abrasion by shifting sand, and observed rates are probably minimal. Eventually, results of such studies on visitor impact and on recovery rates will allow reasonable management decisions on the carrying capacity of a given underwater area and the feasibility of establishing a rotation schedule for heavily used areas (Robinson 1973).

WATER QUALITY AND ENVIRONMENTAL MONITORING

Within National Park Service areas, it is axiomatic that natural water quality should be maintained; but the ease with which this can be done is in direct proportion to the amount of control over the watershed which the Service can exert. Virgin Islands National Park, like some other relatively new parks, still contains large inholdings of private land. Developments on these lands frequently result in increased erosion and fresh-water runoff into park waters. There are also increasing numbers of overnight boat visits and municipal developments on park boundaries, with consequent sewage pollution and solid waste disposal problems.

The island of St. John is fortunate in being situated in an area of strong surface currents; at present the islands immediately up-current (the British Virgin Islands) are relatively undeveloped and are not significantly affecting the quality of marine waters down-current. Should there be considerable industrial development on adjacent islands without safeguards, there is a real danger that incoming water quality will be degraded both chemically and biologically. There exists a serious potential threat, at least esthetically, from local up-current islands and from general surface pollution of the Caribbean, as evidenced by the quantity of nondegrading solid waste and oil residues already accumulating on the east-facing beaches of St. John.

The park personnel have outlined a series of studies which should result in a comprehensive understanding of water movements and water quality around St. John. In cooperation with local government programs the first stages have concentrated on establishing baselines of water quality on which to judge subsequent changes (unpubl. EPA-NPS data). Permanent sampling stations still must be established in critical areas of heavy use and in waters which retain essentially wilderness character. Concurrently, projects are proposed to study the nearshore fixed and tidal currents in order to determine circulation and flushing in certain bays and provide an objective basis for determining the density of boat use allowable in heavy use areas.

BEACHES AND SAND TRANSPORT DYNAMICS

The succession of coral sand beaches along the northern coast is a major esthetic and recreational asset of Virgin Islands National Park. The highly sculptured nature of the coast, with successive bays separated by rocky headlands and varying degrees of wave exposure, creates a complex and largely unstudied pattern of circulation and sand movement. Annual changes in beach character are sometimes great, with cut-back associated with heavy swells arriving from far-distant winter Atlantic storms, and deposition occurring generally during calmer summer conditions. A number of beaches appear to be undergoing net regression, in certain eases altering or eliminating recreational swimming areas and destroying the protective line of sea grape trees. Although some short-term protective measures have been taken, local park managers have resisted major beach management schemes until a full-scale analysis of sand transport, sand sources, wave energies, beach profiles, and historical changes has been effected.

The first phases of such an investigation have been completed through intensive monitoring of a full annual cycle of several north shore beaches by a joint NPS-University of Virginia team. Incoming wave energy parameters including height, approach angle, period, and the duration of storm-produced swell were recorded in conjunction with daily responses of the beaches. Transects with SCUBA and fathometers extended the data collection into the critical sand zones directly offshore. Preliminary analysis shows that 95% of the material making up these beaches is directly derived from nearshore coral reefs (Hoffman et al. 1973). In addition, this material is typically very fine (75% <200 microns), suggesting that even small alterations (natural or artificial) in the incoming wave-energy pattern could have considerable effect on redistributing the beach material, possibly causing it to be deposited on the critical supply reefs offshore.

Decisions regarding the feasibility or appropriateness of any beach management scheme must await final analysis of the current investigations. Presumably additional factors relating to recreational value and the protection of outstanding natural features or established developments will enter into the final determination. Current local policy seems to be tending toward the realization that beaches are dynamic structures whose presence is transient. Dependence upon a given extent or form of a beach is unrealistic, and natural features, facilities, or other developments on such a transient base should be considered expendable. Interruption of the dynamic process, regardless of the sophistication of the scheme, usually requires an energy input of great cost and low efficiency, producing ecological consequences too often unpredicted and unwanted.

SUMMARY

The highest priorities, then, lie in these four areas—visitor impact, consumptive uses, water quality, and beach dynamics. In addition, we have identified a number of further research needs within the park. Some relate to the ecology of coastal wetlands, including salt ponds and mangrove swamps, since these areas play important roles in providing breeding sites for sea birds or act as nursery grounds for juvenile reef fishes. Saltponds are also important buffers between land and sea since the ponds tend to trap silt-laden runoff and prevent turbid waters from flowing directly onto nearshore reefs.

In addition to its support of research aimed specifically at park management problems, Virgin Islands National Park has elected to cooperate with research agencies and conservation groups in the Virgin Islands and in the Caribbean as a whole. This effort generally takes the form of participation in advisory councils and regional conferences, and jointly reviewing proposals for applied and basic research by outside workers. The park is increasingly called upon to provide advice and guidelines for the development of other marine and island parks. An encouraging number of such requests have already been met, from Barbados, Costa Rica, Curacao, Dominica, Guadeloupe, Hawaii, and Vieques.

It is hoped that the National Park Service can continue to provide such advice and services, in the conviction that the role of the Virgin Islands National Park includes not only the preservation and interpretation of the island of St. John, but also an obligation to resource conservation and a rational development of the Caribbean as a whole.

REFERENCES

CLIFTON, H.E., C.V.W. MAHNKEN, J.C. VAN DERWALKER, and R.A. WALLER. 1970. Tektite 1. Man-in-the-Sea project: Marine Science Program. Science 168(3932):659-663.

COLLETTE, B., and S.A. EARLE (eds.). 1972. Results of the Tektite program: ecology of coral reef fishes. Los Angeles County Nat. His. Mus. Sci. Bull. 14, 180 p.

DAMMANN, A.E. 1969. Studies of the fisheries potential of the Virgin Islands. Contrib. No. 1, Virgin Islands Ecological Research Station. 197 p.

DAMMANN, A. E. (ed.). 1970. Exploratory fishing for a source of non-ciguatoxic sport and food fish. Contrib. No. 2, Virgin Islands Ecological Research Station. 48 p.

GLYNN, P.W., L.R. ALMODOVAR, and J. GONZALEZ. 1964. Effects of Hurricane Edith on marine life in La Parguera. Puerto Rico. Crib. J. Sci. 4(2 & 3):335-345.

HIGH, W.L., and A.J. BEARDSLEY 1971. Observations of fish behavior in relation to fish pots. In J.W. Miller, J.G. Van Derwalker, and R.A. Waller (eds.) Tektite 2, Scientists-in-the-Sea. Dept. of Interior-USGPO Report, Stock No. 2400-0682.

HOFFMAN, S., A.H. ROBINSON, and R. DOLAN. 1973. Virgin Islands beach processes investigation: preliminary report. 8p., 3 tables and 28 figs.

KUMPF, H.E., and H.A. RANDALL, 1961. Charting the marine environments of St. John, Virgin Islands. Bull. Mar. Sci. Gulf Caribb. 11(4):543-551.

MILLER, J.W., J.G. VAN DERWALKER, and R.A. WALLER (eds.). 1971. Tektite 2, Scientists-in-the-Sea. Dept of Interior-USGPO Report, Stock no. 2400-0682.

MUNRO, J.L., P.H. REESON, and V.C. GAUT. 1970. Dynamic factors affecting the performance of the Antillean fish trap. Gulf Caribb. Fish. Inst. Proc. 23rd Annual Meeting, Curacao.

OLSEN, D.A., W. HERRNKIND, and I.G. KOBLICK. 1971. Ecological study for the development of lobster management techniques. Puerto Rico International Undersea Laboratory Special Report No. 1. 54 p., 24 figs.

PAULI, D.C., and H.A. COLE. 1970. Summary report on Tektite I. Office of Naval Research Rep. DR 153 S, 53 p.

RANDALL, J. 1964. Contributions to the biology of the Queen Conch, Strombus gigas. Bull. Mar. Sci. Gulf Caribb. 14(2):246-295.

RANDALL, J. 1965. Grazing effect on sea grasses by herbivorous reef fishes in the West Indies. Ecology 46(3):255-260.

RANDALL, J. 1968. Caribbean Reef Fishes. T.F.H. Publications, Jersey City, N.J. 318 p. illus.

ROBINSON, A.H. 1971. Resources management plan, Virgin Islands National Park. unpubl.

ROBINSON, A.H. 1973. Natural vs. visitor-related damage to shallow water corals; recommendations for visitor management and the design of underwater nature trails in the Virgin Islands. V.I. National Park Special Report, 24p. 20 photos.