Jobos Bay National Estuarine Research Reserve
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The Jobos Bay National Estuarine Research Reserve (JBNERR) (Coordinates: 17°57'27.26"N, 66°13'20.13"W)[(http://ctp.uprm.edu/jobos)], originally known as the Jobos Bay National Estuarine Sanctuary (JBNERR), was designated in September 1981 by agreement between the Commonwealth of Puerto Rico Department of Natural and Environmental Resources (DNER)[(http://www.drna.gobierno.pr/)] and the National Oceanic and Atmospheric Administration (NOAA)[(http://www.noaa.gov)]. Designation established Jobos Bay as the eleventh site in the National Estuarine Research Reserve System (NERRS) [(http://www.nerrs.noaa.gov)], as defined in Section 315 of the Coastal Zone Management Act of 1972 (CZMA), as amended. With this designation, Puerto Rico reaffirmed its commitment to develop an estuarine research and education program, preserving, through fee simple acquisition, valuable coastal mangrove forests and associated habitats for the benefit of the general public and ensuring their long-term availability as natural field laboratories to provide information for coastal decision-making. As 2007 NOAA has designated 27 reserves in the USA. Jobos Bay is the second largest estuarine area in Puerto Rico, with three times as much shoreline as any other estuarine zone on the Island. The Bay has a total surface area of 11 square kilometers and depths of up to 8 meters. The Reserve comprises an area of 2,800 acres located at the west end of Jobos Bay, while the Aguirre State Forest (total area, 2,393 acres) borders the north shore and the east end of the Bay.
Prior to its designation in 1981, a large part of the present Reserve area was owned by the Aguirre Corporation, and was known as the Lugo Viñas farm. During the early 1970's, the area was considered as a potential site for an oil transhipment port, in response to the world-wide energy crisis resulting from the oil embargo imposed by the Organization of Petroleum Exporting Counties (OPEC).
However, the lifting of the oil embargo, combined with the enactment of the Puerto Rico Environmental Policy Act (Law # 9 of June 18, 1970, as amended), the creation of the Puerto Rico Department of Natural Resources, and the enactment of the U.S. Clean Water Act, interest in developing the Lugo Viñas farm for industrial purposes declined dramatically. This was due, in great part, to the stringent environmental policies and regulations adopted under the new legislation.
The Commonwealth of Puerto Rico demonstrated interest in the National Estuarine Research Reserve System (formerly known as the National Estuarine Sanctuary Program) in 1974. In 1975, staff from the NOAA Office of Ocean and Coastal Resource Management (OCRM) [formerly known as the NOAA Office of Coastal Zone Management (OCZM)] visited the Island to inspect potential marine sanctuary sites. However, it was not until 1981 that serious consideration was given to the establishment of a National Estuarine Sanctuary under Section 315 of the CZMA.
By 1980, the Aguirre Corporation ceased operations and was in process of liquidation. That year, the Corporation contacted the Sanctuary Programs Division of OCRM/NOAA, proposing to sell the Lugo Viñas farm. Based on the provision of Section 315 of the CZMA, NOAA advised the Aguirre Corporation to re-direct its offer to the Department of Natural Resources.
Early in 1981, DNR submitted a formal application to NOAA for the establishment of the Aguirre Estuarine Sanctuary. The proposal called for the acquisition of approximately 1,205 acres of estuarine property (the Lugo Viñas farm) located on Puerto Rico's south coastal plain. To meet NOAA's match requirements, the Commonwealth proposed to incorporate the Cayos Caribe, a group of seventeen state-owned mangrove islets adjacent to the Lugo Viñas farm, into the Sanctuary. Fifteen of these islets were transferred to the Reserve to comply with the matching requirement. The other two are part of the Aguirre State Forest.
In an extensive estuarine sanctuary site selection process, personnel from OCRM and DNR visited and evaluated several prospective sites in Puerto Rico. These sites, all of which had been included in previous lists of important coastal areas, included the following estuaries: Torrecillas-Piñones (Loíza), Espíritu Santo (Río Grande), El Faro (Fajardo), Humacao Pterocarpus Forest (Humacao), Aguirre/Jobos (Guayama-Salinas), Caño La Boquilla (Mayagüez), and Tortuguero Lagoon (Manatí-Vega Baja). After a careful feasibility analysis, in which both the ecologic and economic realities of the sites were considered, the Jobos site was selected.
In September 1981, the Aguirre site was officially designated as the eleventh National Estuarine Sanctuary, later becoming the Jobos Bay National Estuarine Research Reserve.
The Jobos Bay National Estuarine Research Reserve (JBNERR) covers an area of approximately 1,140 hectares (2,800 acres). The northern limit of the Reserve abuts properties owned by the Puerto Rico Land Authority which are leased to the Gonzalez Farm for crop cultivation, principally fruits and corn. On the northeast boundary of the Reserve is the Aguirre Thermoelectric Power Plant (ATPP) and the old Central Aguirre sugar mill which is no longer operating. Bordering the western limits of the Reserve is the Las Mareas community, and residential construction along El Camino del Indio. Settlement has occurred over the course of years, largely as a result of illegal construction and the filling of wetlands. A section of wetlands in this same general area is owned by the Puerto Rico Housing Department, and is classified for future development. The Reserve's southern boundary extends seaward into Jobos Bay. The Aguirre State Forest is situated along the northern and eastern shores of the Bay.
The legal boundaries of the Reserve are described on property maps and deeds. A recent ground survey has been conducted to ascertain precise boundaries to establish markers for the posting of signage. The absence of boundary markers, particularly along the northern and western perimeters of the Reserve, may have contributed to the illegal filling of property belonging to the Reserve.
A. RESERVE RESOURCES
1. General Description
JBNERR is composed of two major areas: (1) Mar Negro, located on the western margin of the Bay, and (2) Cayos Caribe, a chain of 15 tear-shaped islets located to the southeast. The Mar Negro area comprises the bulk of the Reserve, and consists of mangrove forests and a complex system of lagoons and channels interspersed with salt and mud flats. The Cayos Caribe area consists of mangrove islands fringed by coral reefs and seagrass beds, with small beach sand deposits and upland areas.
2. Physical Resources
a. Climate
JBNERR lies in the south coastal plain within the Subtropical Dry Forest Zone (described by Ewel and Whitmore, 1973). The mountains of the Cordillera Central serve as a barrier to the moisture-laden northeast trade winds. Orographic factors give rise to a zone of low precipitation throughout the entire length of the south coast. Mean annual rainfall is 1,129 mm. The monthly average for the Aguirre station rain gauge, for the 30-year period 1960-90, showed October to be the wettest month, with an average rainfall of 228.6mm (9 inches), and March, the driest, with an average precipitation of 5.4 mm. (1 inch).
Temperature at JBNERR shows little seasonal fluctuation. The mean annual temperature is 26.55 C, with a maximum of 27.4 C during August and a minimum of 24.77 C during February (National Weather Service, 1959, 1965, and 1970). Winds in the Reserve blow regularly from an easterly direction, averaging between six and seven knots.
b. Geology
Berryhill (1960) mapped and described the geological formations and units in the Central Aguirre quadrangle, in which most of JBNERR is located. All of the superficial unconsolidated deposits within JBNERR are mainly Quaternary in age and consist of lagoon, swamp, beach, and alluvial deposits.
Lagoon and swamp deposits cover most of the surface of the Reserve. They consist of unconsolidated clay, silt, and organic matter. These deposits are covered almost entirely by mangroves. Beach deposits occur along the islets of Cayos Caribe. They are composed of sand, gravel, volcanic rock cobbles, and shell fragments. Beaches along the coastal margin consist mainly of carbonate sand derived from nearby fringing reefs. Alluvial plain deposits dominate the northern part of the Reserve, and consist of unconsolidated sand, gravel, and pebbles, which comprise the major water bearing materials of the aquifer. The coastal portion of the aquifer is overlain by permeable, fine grained material. (Renken R.and Gomez, 1987)
An ancient inactive fault, known as the Esmeralda Fault, runs in a northwest-southeast direction north of Jobos Bay. A projection of the fault suggests that it probably passes under Jobos Bay towards the Caribbean Sea. Calcite deposits tightly seal this system below weathering penetration. There are no metallic mineral deposits of commercial value in the general areas of the Reserve. Small amounts of hematite are found several kilometers northeast of Jobos Bay.
c. Hydrology
The hydrologic conditions of the area are typical of a semiarid region. The principal streams draining the watersheds from Salinas to Patillas are the Río Salinas, Río Seco, Quebrada Melanía, Río Nigua and Río Grande de Patillas. Of these, only the Río Seco drains into Jobos Bay, near the Puente de Jobos community, to the east of the Reserve. Various small streams flow into the Bay from the north. Two of these, Quebrada Aguas Verdes and Quebrada Coqui, join and flow directly into the Bay. Many of these streams cease to flow in the upper part of the valley due to infiltration into the aquifer through the highly permeable material of the alluvial valley.
The South Coastal Plain aquifer extends from Ponce to Patillas. The coastal plain consists of a series of successive fan deltas formed by steep gradients, and intermittent streams having small drainage areas. The hydrogeologic characteristics of the South Coastal Plain vary considerably from site to site. Hydrological studies conducted by USGS in the south suggested the existence of six subsystems from Salinas to Patillas, based on local hydrogeologic characteristics. These were, in turn, classified into three main prototypical groups, the Salinas fan delta, the Jobos area, and the Arroyo fan delta. Within these areas, the main aquifer is adjacent to the coast (Quiñones, V., 1990). Jobos Bay NERR is within the Salinas fan delta group.
Groundwater is the main source of freshwater for the Jobos Bay estuary. Three main geohydrologic units constitute the aquifers in the South Coastal Plain; 1) a shallow water table and confining clay unit, 2) the main groundwater flow zone and, 3) the regolith geohydrologic unit (Quiñones V. and others 1990). The confining formation, mainly present along the coastal area, is a fine grained, barely permeable clay or silt bed, averaging about 20 feet in thickness, although in some areas it is less than 10 feet in thickness. It extends from one mile (at Bahia de Jobos) to four miles in the Salinas fan delta. Freshwater inflow to the mangrove wetlands occurs from the shallow aquifer and from the principal flow zone, (Quiñones V. And others, 1997). Aquifer water flow closely follows topographic patterns in these areas.
Prior to development in the area, the aquifer was recharged mainly by stream seepage and by rainfall. Mean annual rainfall in Aguirre is 40 inches, and 77 inches in the mountains. Runoff from heavy rains in the mountains recharge the aquifer by infiltration through riverbeds. Irrigation practices, principally for sugar cane cultivation, resulted in modifications to the hydrological pattern. Between 1914 and the early 1990s, an extensive network of canals and a diversion tunnel were used to carry water from Lago Carite and Lago Patillas to the coastal plain from Salinas to Patillas. A considerable percentage of this irrigation water acted as a source of aquifer recharge.
B. Biological Resources
a. Mangroves: Overview
The principal plant associations of JBNERR are mangroves and associated salt flats. Mangroves act as sediment traps that retard water movement and trap suspended materials, gradually raising the land level and producing organic soil. The rich protected substrate provides habitat for a large variety of organisms, which in turn serve as the food base for marine animals. Some fish and shellfish found in the mangrove roots are of commercial value, while others spend only a part of their life cycles breeding or spawning there. Mangroves provide nesting sites for both native and migratory birds. In addition, mangroves offer excellent opportunities for recreation, as well as for scientific research.
Four species of mangroves are found within the Reserve: Red Mangrove (Rhizophora mangle); White Mangrove (Laguncularia racemosa); Black Mangrove (Avicennia germinans); and Buttonwood Mangrove (Conocarpus erectus). Three of the five mangrove forest types (described by Lugo and Snedaker, 1973) occur within the Reserve: fringe forests, basin forests, and overwash forest. Riverine and dwarf forests are not found in JBNERR.
(1) Fringe Mangrove Forests: These occur along the seaward edge and along the coastal lagoons and channels that connect the entire system and the open sea. The degree of structural development of these mangroves is controlled primarily by the quality of the soil in which they grow, and the wave intensity. Fringe mangroves are usually exposed to the tides, a relatively constant salinity regime, low nutrient concentration, wave action, salt spray, and strong winds. Based on tree density, red mangroves comprise about 75 per cent of the fringe forest, and white mangroves comprise the remaining 25 per cent
A wide assortment of marine organisms is associated with the submerged prop root system of the red mangrove. Competition for space on these roots is high. Invertebrates present include crustaceans, mollusks, bryozoans, sponges, echinoderms, polychaetes, and cnidarians. Vertebrates include fish and a wide variety of tunicates. Algae from different taxonomic groups are abundant.
Emergent segments of the prop roots, as well as the stems of other mangrove species, are used as substrate for invertebrates, especially crustaceans and mollusks. Associated with these diverse root and stem communities is a rich variety of abundant wildlife, especially birds. Fringed mangroves serve as nurseries for many species of fish, which migrate from nearby coral reefs and seagrass beds during part of their life cycle. Many species of reef fish seek refuge in fringe mangroves after reefs are damaged by hurricanes, such as David in 1979. Dissolved and particulate organic material and other nutrients are exported to adjacent sub-tidal communities.
Fringe mangroves play an important role in protecting coastal lands, as they act as buffers that absorb wave energy, thereby attenuating their force and preventing coastal erosion.
(2) Basin Mangrove Forests: These mangroves forests are better developed along the north coast of Puerto Rico, but some are present in JBNERR, in close association with the fringing forest. These forests are normally separated from direct contact with the ocean, except during very high tides or during storms. The dominant species in this forest type is the salinity-tolerant black mangrove, and to a lesser degree, white mangrove. Occasionally, the buttonwood mangrove is found within the innermost reaches of the basin forest. The northern part of the Reserve is a basin forest in which fresh water species such as ferns and palm trees are found in association with the black mangrove. Two species of decapod crustaceans are conspicuous in this type of forest: the fiddler crab (Uca pugnax) and the colorful mangrove crab (Goniopsis cruentata). Many bird species use these habitats.
(3) Overwash Mangrove Forests: These forests develop off-shore over shallow platforms of cays on the inner insular shelf. These are overtopped daily or less frequently by high tides or storm surges. As this forest type develops, the extensive prop root system causes a reduction of water circulation within the inner zones of the islets, and the inner red mangrove trees eventually die due to salt accumulation. These are replaced by stunted black mangroves, which also die as the soil salinity increases beyond their threshold tolerance, creating a hypersaline lagoon in the center or core of the islet. All stages of this process are represented within the Reserve, particularly in the Cayos Caribe area. The overwash mangroves also support healthy prop root marine communities, and serve as rookeries for several bird species found in the region.
b. Salt Flats
Hypersaline lagoons and salt flats occur inland from the mangrove forests. They are formed as a result of reduced inland runoff, higher evaporation rates, and reduced rainfall. Dead black mangroves are often seen in these lagoons. Where vegetation does exist, it consists mainly of salt-tolerant species, such as Batis maritima and Sesuviun portulacastrum, which have thick fleshy leaves adapted for water storage. Generally, these species are not intermixed. Sesuviun appears to prefer drier soils and typically grows on higher ground, while Batis is often found in wetter substrates like those associated with the mangrove fringe.
c. Other Forest Types
The native vegetation of the Jobos Bay area has been altered almost entirely by agriculture, urban development, and industrialization. Little is known about the early history, ecology, and physiographic features of the area. Gleason and Cook (1926, as cited in PRDNR, 1983) described the original vegetation types of the area surrounding JBNERR as a semi-evergreen seasonal forest type which covered the great majority of the area from the coast to medium elevations in the hills. Dominant species were Bucida buceras and Guazuma ulmifolia. This forest was separated from the mangrove forest by salt flats. Today, the following vegetation types exist: secondary forest, secondary woodland, evergreen littoral woodland, coconut palm plantations,mangroves, swamps, salt flats, sugar cane, and minor fruit crops.
The area north of Jobos Bay, formerly in sugar cane, is now planted mainly in corn, fruits, beans and other vegetables. Two coconut palm (Cocos nucifera) stands are located near the central area of Mar Negro. Royal palm stands are also present. The area is inhabited by the land crab (Cardisoma guanhumi) and the plant (Typha dominguensis).
The Cayos Caribe [1] also contain small areas of evergreen littoral woodland and/or secondary vegetation, which includes five species of trees, four species of shrubs, and three species of vines.
d. Seagrass Beds
Three species of seagrasses occur in the Reserve: Turtle grass (Thalassia testudinum), manatee grass (Syringodium filiforme), and Halophila decipiens. The first two are abundant. They have similar ecology and grow intermixed at some locations while Halophila is typical of deeper areas.
Seagrass beds develop mainly in low energy zones protected by fringing reefs. Light penetration and turbidity of the water column are the major limiting factors in their distribution. Thalassia beds are present from the intertidal zone to depths of up to ten meters. Large, well-developed meadows occur at depths of two meters or less. These meadows occupy most of the shallow bottoms just offshore from the mangrove fringe. Dense beds of thalassia are also present in semi-enclosed areas with good circulation and clear waters. They are absent from the exposed reef fronts which are subject to high energy wave action, but may develop on the inundated central portion of the reef flats. Thalassia meadows are also present in the shallow lagoon side of the reefs, where they grow in a rather variable band just behind the reef flat.
Seagrass beds serve as habitat and feeding and nursery ground for a wide variety of marine organisms, including conch, octopus, squid, shrimp, and juvenile lobster. Some of these organisms, especially lobster, octopus and conch, are of considerable commercial value. The grunt (Haemulon flaveolineatum) depends entirely on seagrass beds as a food source. The endangered hawksbill sea turtle (Erectmochelys imbricata), the green sea turtle (Chelonia mydas), and the West Indian manatee (Trichechus manatus) [2] have been sighted in the seagrass beds of the Reserve.
e. Coral Reefs
Coral reefs, together with mangroves and seagrass beds, form one of the most complex, diverse, and productive coastal associations in the world. The islets of Cayos Caribe are fronted by a reef-flat terrace containing patches of green zoanthis (Zoanthus sociatus), seaward of which the coral reef begins to appear.
The coral reefs at Jobos Bay present the typical zonation of Caribbean reefs (Figure). Finger corals, gorgonians, zoanthids, and seagrass beds characterize the scoured channels between the Cayos Caribe islets. The reef flat, usually less than 0.5 m deep and exposed during low tide, is dominated by an intermixed association composed of isolated coral heads of finger coral (Porites asteroides), Favia fragum, and fire corals (Millepora). Zoanthids, mainly Zoanthus sociatus, are also a principal component of the reef platforms.
The reef's surge zone is a high wave energy area that ranges in depth from one to six meters. The dominant coral species in this area are the fire coral and the elkhorn coral (Acropora palmata). The reef slope drops off the depths of 18 meters, and contains massive heads of hard coral, including brain coral (Diploria), star coral (Montastrea) and various species of gorgonian soft corals. Eleven species of hard corals and ten species of soft corals have been reported in the area.
García and Castro (1976) have provided a more complete description of the corals present in the reef flat, the Millepora-Palithoa zone, the Acropora zone, the Butress zone, and the reef slope of Cayos Caribe. The reef flat is mainly composed of Porites porites, P. asteroides, Favia fragum, Agaricia agaricites and Siderastrea radians. Encrusting zoanthis were also observed. The Millepora-Palithoa zone is composed of Acropora palmata, Millepora complanata, Palithoa caribaea, and Erythropodium caribaeum. Calcareous algae and sea unchins were also reported. The Acropora zone was composed of A. palmata and small scattered colonies of massive corals, zoanthids, turf algae and gorgonians. The butress zone is composed of massive and scleractinian corals, encrusting corals reaching their optimal development at this reef. The reef slope is composed of whip-like gorgonians, erect and encrusting sponges and scattered colonies of scleractinian corals.
f. Plankton
-- Phytoplankton [3]
The most recent samplings for phytoplankton have shown a dominance of diatoms species. Thirty-six different diatom [4] genera and seven dinoflagellate [5] genera were represented in samples obtained in 1995. Dinoflagellates constituted the second most abundant group. The average total density of phytoplankton ranged from less than 200 cell/ml near Cayos Caribe to a maximum of 1150 cells/ml in Mar Negro. (See Appendix C).
-- Zooplankton [6]
Copepods [7], including larval stages, were the dominant group in zooplankton samples obtained from the mangrove lagoons and the bay sampling stations during 1995. The Cyclopoida copepods were the most abundant in all sampling stations during most of the period covered, from February through August. Average total counts of copepods in Mar Negro ranged from 20,000/m3 to 260,000 /m3, while in the Cayos Caribe area the counts ranged from about 500/ m3 to 11,000 /m3. Cyclopoida, and Harpacticoida copepods are the most common in samples. (See Appendix C).
g. Benthos
By definition, benthic organisms are those living in or on the sea bottom. Assessments conducted prior to the construction of the thermoelectric plant identified a great diversity of benthic organisms in association with Thalassia [8] beds and mangrove roots.
h. Ichtiofauna
The Jobos Bay area was divided by Martin and Pathus (1975) into four zones to conduct a fish survey. A survey conducted by DNR in 1981 accounted for 68 families and 263 fish species. The most common sport and commercial fishes are whalebone anchovies, herrings, jacks, and parrotfish. García and Castro (1996) reported a total of 33 species, representing 13 families of diurnal non-cryptic reef fish at the reef crest of Cayos Caribes. A total of 40 species of diurnal non-cryptic reef fish, distributed in 16 families were identified during a visual survey at the butress zone of Cayos Caribe. Fourteen species were identified at Cayo Puerca. García and Castro (1996) reported 18 species during a visual survey at the root community on the fringing mangrove stations in Cayos Caribe on September 1996.
i. Reptiles and Birds
Garcia and Rivera (1981) studied the lizard populations in the mangroves of the southern region of Puerto Rico. Anoles (Anolis cristatellus, A. pulchellus, and A. stratulus) and the ground lizard (Ameiva exsul) were the only lizards present in the Jobos Bay area. Tree frogs (Eleutherodactylus sp.) and the marine toad (Bufo marinus) were the only amphibians inhabiting JBNERR.
The relatively undisturbed mangrove ecosystem of Mar Negro makes the area a haven for pelicans, herons, shorebirds, and waterfowl. A total of 87 bird species have been sighted in Jobos Bay.
j. Endangered Species
The Reserve is a very important habitat for endangered species. As far as is known there is no record of exotic species in the Reserve. The brown pelican, the peregrine falcon, the Puerto Rican plain pigeon, and the yellow-shouldered blackbird are endangered bird species found in JBNERR. Two other endangered species encountered in the Reserve are the hawksbill sea turtle (Eretmochelys imbricata) and the West Indian manatee (Trichechus manatus). The hawksbill turtle forages in shallow waters and feeds on the bottom of reef areas and Thalassia beds. It has a preference for invertebrates, algae, and submerged roots.
The manatee historically was found in shallow coastal waters and inland lakes throughout much of the tropical and subtropical regions of the New World Atlantic, including the Caribbean islands. However, at the present time, manatees are rare or extinct in most parts of their former range (Brownell, 1980). Recent surveys indicate a total Puerto Rican population of less than 100 animals. Small groups are frequently sighted on the south coast and around the estuary of the Fajardo River on the east coast. Manatees have also been sighted in Mar Negro and the Jobos Bay area.
4. Cultural and Historic Resources
The Reserve and adjacent areas contain several important archaeological sites. A large Indian settlement was located at the Carmen site adjoining the Reserve. The casual discovery of stone figurines ("Cemi") [9] in the Central Aguirre area reflects settlements of the Taino Indians [10], the most important indigenous cultural group of the Island. However, the area has never been surveyed in a systematic manner by an archaeological team (Fewkes, 1904; Anon. 1975), and it is possible that the area contains other important archaeological sites (Ovidio Davila, pers. com.). While a desirable future activity, funds for such a survey are not currently available.
The Aguirre Sugar Mill itself is an important cultural and historic asset. In 1898, an American company bought the Aguirre properties. They modernized the sugar technology and developed a complex on Jobos Bay that included the sugar mill and refinery, plus administrative, commercial, institutional, recreational, and residential areas. The recreational facilities included a golf course, a hotel, a swimming pool, and a social club. The residence of the company's president was located on the highest point of the property, and commanded an excellent vista of the Bay. The house is typical of the architectural style of the great plantation mansions of the southeastern United States.
