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Public Health Assessment
Fish and Shellfish Evaluation,
Isla de Vieques Bombing Range,
Vieques, Puerto Rico

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June 27, 2003
Prepared by:

Federal Facilities Assessment Branch
Division of Health Assessment and Consultation
Agency for Toxic Substances and Disease Registry

Appendices A - C

Appendix A: ATSDR Glossary of Environmental Health Terms

Absorption: How a chemical enters a person's blood after the chemical has been swallowed, has come into contact with the skin, or has been breathed.

Acute Exposure: Contact with a chemical that happens once or only for a limited period of time. ATSDR defines acute exposures as those that might last up to 14 days.

Additive Effect: A response to a chemical mixture, or combination of substances, that might be expected if the known effects of individual chemicals, seen at specific doses, were added together.

Adverse Health Effect: A change in body function or the structures of cells that can lead to disease or health problems.

Antagonistic Effect: A response to a mixture of chemicals or combination of substances that is less than might be expected if the known effects of individual chemicals, seen at specific doses, were added together.

ATSDR: The Agency for Toxic Substances and Disease Registry. ATSDR is a federal health agency in Atlanta, Georgia that deals with hazardous substance and waste site issues. ATSDR gives people information about harmful chemicals in their environment and tells people how to protect themselves from coming into contact with chemicals.

Background Level: An average or expected amount of a chemical in a specific environment. Or, amounts of chemicals that occur naturally in a specific environment.

Biota: Used in public health, things that humans would eat - including animals, fish and plants.

Cancer: A group of diseases which occur when cells in the body become abnormal and grow, or multiply, out of control.

CEL: Cancer Effects Level. Dose that produces significant increases in the incidence of cancer or tumors.

Carcinogen: Any substance shown to cause tumors or cancer in experimental studies.

Chronic Exposure: A contact with a substance or chemical that happens over a long period of time. ATSDR considers exposures of more than one year to be chronic.

Completed Exposure Pathway: See Exposure Pathway.

Comprehensive Environmenta Response, Compensation, and Liability Act (CERCLA): CERCLA was put into place in 1980. It is also known as Superfund. This act concerns releases of hazardous substances into the environment, and the cleanup of these substances and hazardous waste sites. ATSDR was created by this act and is responsible for looking into the health issues related to hazardous waste sites.

Concern: A belief or worry that chemicals in the environment might cause harm to people.

Concentration: How much or the amount of a substance present in a certain amount of soil, water, air, or food.

Contaminant: See Environmental Contaminant.

Dose: The amount of a substance to which a person may be exposed, usually on a daily basis. Dose is often explained as "amount of substance(s) per body weight per day."

Dose / Response: The relationship between the amount of exposure (dose) and the change in body function or health that result.

Duration: The amount of time (days, months, years) that a person is exposed to a chemical.

Environmental Contaminant: A substance (chemical) that gets into a system (person, animal, or the environment) in amounts higher than that found in Background Level, or what would be expected.

Environmental Media: Usually refers to the air, water, and soil in which chemicals of interest are found. Sometimes refers to the plants and animals that are eaten by humans. Environmental Media is the second part of an Exposure Pathway.

US Environmental Protection Agency (EPA): The federal agency that develops and enforces environmental laws to protect the environment and the public's health.

Epidemiology: The study of the different factors that determine how often, in how many people, and in which people will disease occur.

Exposure: Coming into contact with a chemical substance.(For the three ways people can come in contact with substances, see Route of Exposure.)

Exposure Assessment: The process of finding the ways people come in contact with chemicals, how often and how long they come in contact with chemicals, and the amounts of chemicals with which they come in contact.

Exposure Pathway: A description of the way that a chemical moves from its source (where it began) to where and how people can come into contact with (or get exposed to) the chemical.

ATSDR defines an exposure pathway as having 5 parts:

  1. Source of Contamination,
  2. Environmental Media and Transport Mechanism,
  3. Point of Exposure,
  4. Route of Exposure, and
  5. Receptor Population.

When all 5 parts of an exposure pathway are present, it is called a Completed Exposure Pathway. Each of these 5 terms is defined in this Glossary.

Frequency: How often a person is exposed to a chemical over time; for example, every day, once a week, twice a month.

Hazardous Waste: Substances that have been released or thrown away into the environment and, under certain conditions, could be harmful to people who come into contact with them.

Health Effect: ATSDR deals only with Adverse Health Effects (see definition in this Glossary).

Indeterminate Public Health Hazard: The category is used in Public Health Assessment documents for sites where important information is lacking (missing or has not yet been gathered) about site-related chemical exposures.

Ingestion: Swallowing something, as in eating or drinking. It is a way a chemical can enter your body (See Route of Exposure).

Inhalation: Breathing. It is a way a chemical can enter your body (See Route of Exposure).

MRL: Minimal Risk Level. An estimate of daily human exposure - by a specified route and length of time -- to a dose of chemical that is likely to be without a measurable risk of adverse, noncancerous effects. An MRL should not be used as a predictor of adverse health effects.

NPL: The National Priorities List. (Which is part of Superfund.) A list kept by the US Environmental Protection Agency (EPA) of the most serious, uncontrolled or abandoned hazardous waste sites in the country. An NPL site needs to be cleaned up or is being looked at to see if people can be exposed to chemicals from the site.

NOAEL: No Observed Adverse Effect Level. The highest dose of a chemical in a study, or group of studies, that did not cause harmful health effects in people or animals.

No Apparent Public Health Hazard: The category is used in ATSDR's Public Health Assessment documents for sites where exposure to site-related chemicals may have occurred in the past or is still occurring but the exposures are not at levels expected to cause adverse health effects.

No Public Health Hazard: The category is used in ATSDR's Public Health Assessment documents for sites where there is evidence of an absence of exposure to site-related chemicals.

PHA: Public Health Assessment. A report or document that looks at chemicals at a hazardous waste site and tells if people could be harmed from coming into contact with those chemicals. The PHA also tells if possible further public health actions are needed.

Plume: A line or column of air or water containing chemicals moving from the source to areas further away. A plume can be a column or clouds of smoke from a chimney or contaminated underground water sources or contaminated surface water (such as lakes, ponds and streams).

Point of Exposure: The place where someone can come into contact with a contaminated environmental medium (air, water, food or soil). For examples:

the area of a playground that has contaminated dirt, a contaminated spring used for drinking water, the location where fruits or vegetables are grown in contaminated soil, or the backyard area where someone might breathe contaminated air.

Population: A group of people living in a certain area; or the number of people in a certain area.

Public Health Hazard: The category is used in PHAs for sites that have certain physical features or evidence of chronic, site-related chemical exposure that could result in adverse health effects.

Public Health Hazard Criteria: PHA categories given to a site which tell whether people could be harmed by conditions present at the site. Each are defined in the Glossary. The categories are:

  1. Urgent Public Health Hazard
  2. Public Health Hazard
  3. Indeterminate Public Health Hazard
  4. No Apparent Public Health Hazard
  5. No Public Health Hazard

Receptor Population: People who live or work in the path of one or more chemicals, and who could come into contact with them (See Exposure Pathway).

Reference Dose (RfD): An estimate, with safety factors (see safety factor) built in, of the daily, life-time exposure of human populations to a possible hazard that is not likely to cause harm to the person.

Route of Exposure: The way a chemical can get into a person's body. There are three exposure routes:

- breathing (also called inhalation),

- eating or drinking (also called ingestion), and

- or getting something on the skin (also called dermal contact).

Safety Factor: Also called Uncertainty Factor. When scientists don't have enough information to decide if an exposure will cause harm to people, they use "safety factors" and formulas in place of the information that is not known. These factors and formulas can help determine the amount of a chemical that is not likely to cause harm to people.

Source (of Contamination): The place where a chemical comes from, such as a landfill, pond, creek, incinerator, tank, or drum. Contaminant source is the first part of an Exposure Pathway .

Special Populations: People who may be more sensitive to chemical exposures because of certain factors such as age, a disease they already have, occupation, sex, or certain behaviors (like cigarette smoking). Children, pregnant women, and older people are often considered special populations.

Statistics: A branch of the math process of collecting, looking at, and summarizing data or information.

Synergistic effect: A health effect from an exposure to more than one chemical, where one of the chemicals worsens the effect of another chemical. The combined effect of the chemicals acting together are greater than the effects of the chemicals acting by themselves.

Toxic: Harmful. Any substance or chemical can be toxic at a certain dose (amount). The dose is what determines the potential harm of a chemical and whether it would cause someone to get sick.

Toxicology: The study of the harmful effects of chemicals on humans or animals.

Tumor: Abnormal growth of tissue or cells that have formed a lump or mass.

Uncertainty Factor: See Safety Factor.

Urgent Public Health Hazard: This category is used in ATSDR's Public Health Assessment documents for sites that have certain physical features or evidence of short-term (less than 1 year), site-related chemical exposure that could result in adverse health effects and require quick intervention to stop people from being exposed.




Appendix B: Sampling Methods for ATSDR's Fish and Shellfish Investigation

Sampling Techniques

At each location, field personnel collected fish and shellfish using the following methods:

  • Spearfishing. Divers used spearguns, aided by self-contained underwater breathing apparatus (SCUBA), to collect fish. Where possible, the divers aimed for the fish's abdomen to avoid damaging the body meat (see Picture 11).
  • Fishing poles. While on board the surface support boat, field personnel used fishing poles baited with squid.
  • Hand capture. Lobster and conch were collected by hand, while snorkeling or while using SCUBA. Fiddler crabs were also collected by hand.
  • Traps. Large wooden traps baited with fruit (e.g., mangos) were used to capture land crabs (see Picture 12).
  • Field purchase. Field personnel purchased fish and lobsters from a local fish market. No attempt was made to verify the area from which the fish and lobsters were caught, though the market staff stated that all fish and lobsters sold in the market were caught locally.

Fish identifications were made using the field guide "Reef Fish Identification; Florida, Caribbean, Bahamas" (Humann 1994) and invertebrate identifications were made using the field guide "Caribbean Reef Invertebrates and Plants" (Colin 1978).

An attempt was made to collect organisms of the same approximate size (by species) at each location so that final tissue concentrations would be comparable. Because the reefs around Vieques are heavily fished, many of the fish and shellfish collected by field personnel were small, and it was not possible to collect five individuals of each of the species at every sampling location, as originally planned. Though yellowtail snapper was listed as the most commonly caught and consumed fish in Vieques (Caro et al. 2000), few yellowtail snappers were seen at any of the sampling locations, and those that were approachable were quite small (less than 30 cm).

The Caribbean Fishery Management Council size regulations were observed where possible (see text box for details). Because the field sampling trip was scheduled for mid-July, during the closed season for collecting queen conch and land crabs, field personnel were not able to abide by the seasonal regulations. The Puerto Rico Department of Natural and Environmental Resources (DNER), however, granted permission to collect these specimens.

The Caribbean Fishery Management Council size regulations were observed where possible
Species Regulation
Yellowtail Snapper minimum total length = 12 inches [30 centimeters (cm)]
Queen Conch minimum total length = 9 inches (23 cm), with greater than 3/8 inch (1 cm) lip thickness
Spiny Lobster minimum carapace length = 3.5 inches (9 cm)
Organism Collection

Fish and shellfish were collected using the commercial dive charter boat, "Moonglow," operated by the Blue Caribe Dive Center, in Esperanza, Vieques (see Picture 13). The captain made suggestions regarding specific reefs at the desired sampling locations. Reef names, where known, were supplied by the boat captain. Areas unfamiliar to the captain, and/or not named on nautical charts, were named (for the purposes of this study) by field personnel. The latitude and longitude of the approximate center of each sampling location was determined using a global positioning system (GPS) unit made available on the chartered dive boat. Fish and shellfish were collected from July 16-20, 2001. Sample locations are depicted in Figure 3.

  • On the first sampling day, field personnel traveled to Location 3. Dives were made on Bucky Reef and Patti Reef, which are regularly visited by recreational divers and fisherman. Fish were collected using spearguns and a single lobster was collected by hand.
  • On the second sampling day, field personnel traveled to Location 2. Dives were made on the former USS Killen. Fish were collected using spearguns and fishing poles, and conch were collected by hand. Field personnel were unsuccessful in their attempt to collect lobster from Location 2. Land crabs and fiddler crabs were collected from the shore area adjacent to the former USS Killen.
  • On the third sampling day, field personnel traveled to Location 1. Dives were made on two small, unnamed reefs. The first small unnamed patch reef (North LIA 1) was visible from the surface, since the reef crest was partially emergent at low tide. The other reef (North LIA 2) was located by towing a diver behind the boat (see Picture 14). Fish were collected using spearguns and fishing poles, lobster and conch were collected by hand. Land crabs and fiddler crabs were collected from the shore area adjacent to the patch reef at North LIA 1.
  • On the fourth sampling day, field personnel traveled to Location 4. Dives were made on two unnamed reefs (Isabel 1 and Isabel 2) and under a dock near the end of the Mosquito Pier. Fish were collected using spearguns and fishing poles. Field personnel were unsuccessful in their attempt to collect lobster and conch from Location 4.
  • On the fifth sampling day, field personnel split into two teams. The first team traveled to Locations 3, 5, and 6. At Location 6, dives were made on an unnamed reef (West End). Fish were collected using spearguns and conch were collected from a nearby seagrass bed by hand. Field personnel were unsuccessful in their attempt to collect lobster from Location 6. On the return trip from Location 6 to Esperanza, field personnel stopped at Location 3 (Arena Reef) to collect conch. The second team retrieved land crabs from traps that had been set the previous day on land near Location 6 and purchased fish from a fish market in Isabel Segunda (Location 5).
Tissue Sampling

ATSDR is aware that some residents of Vieques may eat more than the fillet of a fish (e.g., residents may use the whole fish to make soup stock). However, the bones and organs of the fish are typically not consumed. ATSDR chose to sample fish fillets to evaluate the maximum exposure potential to chemicals in the fish. This procedure tends to be more sensitive than analyzing the whole fish, which may cause the concentrations to be diluted. In addition, by sampling fish fillets, ATSDR is following standard protocol for human health evaluations and allowing for a comparison of these results to other studies.

Fish were processed according to EPA's Standard Operating Procedure # 2039 Fish Handling and Processing (EPA/ERT 1998). Each fish was weighed, measured for total length, and observed both externally and internally for obvious abnormalities (e.g., neoplasms, parasites, deformities) (see Pictures 15 and 16). Fish were filleted, taking care not to include any portion of the meat that had been damaged by the spear, and a sample of the fillet was wrapped in plastic wrap, placed in a sealable plastic bag, and placed on wet ice until it could be frozen (in less than 6 hours). Sometimes fillets from both sides of the fish were collected in order to obtain sufficient tissue mass for analytical requirements.

Each lobster was weighed whole, measured for carapace length, and observed externally for obvious abnormalities. Lobster abdomens (i.e., tails) were separated from the carapace and the meat removed. The entire tail meat sample was wrapped in plastic wrap, placed in a plastic bag, and placed on wet ice until it could be frozen (in less than 6 hours).

Each conch was weighed (in its shell), measured for total shell length, and observed externally and internally for obvious abnormalities (see Pictures 17 and 18). Conch were removed from their shells by punching a hole in the shell at the second or third spire whorl, cutting the animal's attachment with a fillet knife, and pulling the animal out of the shell by its operculum. The conch meat was then separated from the operculum, mouth and eyes, and internal organs, wrapped in plastic wrap, placed in a plastic bag, and placed on wet ice until it could be frozen (in less than 6 hours).

The sex of the land crabs was recorded and the crab meat was "picked" from the chelipeds and the body (see Pictures 19 and 20). Since a single crab could not supply enough easily picked meat to meet the sample quantity needed for chemical analyses, the meat from several crabs was composited until a sufficient quantity of meat was obtained. Land crab composite samples were made from an equal number of male and female crabs. The meat was wrapped in plastic wrap, placed in a plastic bag, and placed on wet ice until it could be frozen (in less than 6 hours).

Fiddler crabs were analyzed for whole body burdens; therefore, they were weighed en masse to ensure a sufficient sample was collected for analysis. Though fiddler crabs were not individually weighed or measured, notes were made of obvious external abnormalities. Rinsing fiddler crabs of sand and dirt was inadvertently omitted prior to placing them into sample containers. The composite sample of crabs was placed in a plastic bag and placed on wet ice until it could be frozen (in less than 6 hours).

Tissue Analysis

All tissue samples were shipped on dry ice, via overnight delivery to EPA's subcontracted laboratory, Compuchem, for analysis of heavy metals, explosives compounds, percent lipids, and percent moisture. One gram tissue samples were analyzed for heavy metals according to EPA Method 6010B (utilizing inductively coupled argon plasma-atomic emission spectrometry and co-vapor atomic absorption; the method description can be found at the following URL: http://www.epa.gov/epaoswer/hazwaste/test/6010b.pdf). Two gram tissue samples were analyzed for explosives compounds according to EPA Method 8330 (utilizing high performance liquid chromatography; the method description can be found at the following URL: http://www.epa.gov/epaoswer/hazwaste/test/8330.pdf>). One specimen of each of the four species purchased from the fish market (red hind, white grunt, yellowtail snapper, and spiny lobster) was submitted to Brooks Rand Ltd. for separate methylmercury analysis. Methylmercury was determined using Brooks Rand method BR-0011 (utilizing aqueous phase ethylation, Tenax trap collection, gas chromatograph separation, isothermal decomposition, and cold vapor atomic fluorescence spectroscopic detection).

Quality Control

A qualified third party validator, the Response, Engineering and Analytical Contract (REAC), validated the results from the labs.

Metals analysis. Matrix spike/matrix spike duplicates were performed for the metals analysis. Percent recoveries ranged from 42 to 118; all 272 values were within acceptable quality control (QC) limits. The relative percent differences ranged from zero to two; all 136 values were within the acceptable QC limits. Laboratory duplicates were analyzed; relative percent differences ranged from zero to 154. A laboratory control sample standard was analyzed for each data package; percent recoveries ranged from 54 to 116.

Explosives Analysis. Matrix spike/matrix spike duplicates were performed for the explosives analysis. Percent recoveries ranged from 0 to 142; 178 or 192 values were within acceptable QC limits. The relative percent differences ranged from zero to 101; 88 of 93 values were within the acceptable QC limits. A laboratory control sample standard was analyzed for each batch. Percent recoveries ranged from 8 to 154; 90 of 96 values were within the acceptable QC limits. Each sample was spiked with 1,4-dinitrobenzene (surrogate) prior to extraction. The surrogate percent recoveries ranged from 63 to 158; 153 of 154 vales were within acceptable QC limits. The data associated with the only explosives compound detected, HMX, in fiddler crabs, fell within acceptable QC limits.




Appendix C: Conditions of the Reef

The following general reef conditions were noted by the lead Marine Scientist during ATSDR and EPA/ERT's fish and shellfish sampling. He is a certified diver with over 20 years experience diving on coral reefs, with formal training at the West Indies Laboratory (St. Croix, US Virgin Islands) in scientific diving, coral reef biology, and tropical marine ecology. Throughout his career he has made more than 500 dives on Caribbean reefs and seagrass beds in the Florida Keys, the US and British Virgin Islands, the Cayman Islands, St. Martin, and Vieques. His Master's degree focused on natural and anthropogenic stresses to seagrass beds and assessing population dynamics of resident green sea turtles. In addition, he managed an aquatic toxicology laboratory that studied the effects of environmental pollution to freshwater and marine fish, invertebrates, and plants and assisted the National Park Service and EPA with coral disease monitoring studies in St. John and St. Croix, respectively.

General

When comparing the sampling locations, it is important to note that the different locations exhibited varied depths, bottom structures (e.g., reef, rubble, wreck), currents, and fishing pressures. All descriptions of the appearance and general health of the sampling locations are subjective. No quantitative data were collected on the numbers of species or the number of individuals of each coral or fish species observed. In general, it appeared that all sample locations supported diverse, healthy populations of marine organisms. The impression of each of the divers was that the reefs were in good condition and that the fish appeared healthy.

All of the reefs and structures that were bordered by seagrass beds were surrounded by a sandy "halo" and then a healthy seagrass bed that was dominated by turtle grass (Thalassia testudinum). The halo is a typical feature of reefs and underwater structures that is caused by grazing organisms (most commonly the sea urchin, Diadema antillarum) leaving the shelter of the reef at night to feed on the surrounding seagrass beds (see Picture 21). Lack of a halo would have been indicative that grazers were not present. Turtle grass is the climax species in the succession from bare sand to algae to seagrass, and a dense bed of turtle grass is an indication of a mature, healthy system (McRoy and Helfferich 1977; Zieman and Zieman 1989).

At Locations 1, 2, and 6, many conch shells were found that had holes punched out by fishermen who pulled the meat out and threw the shells back before leaving the area. A number of holed shells were clearly not of legal size. Location 3 had a healthy population of conch, most likely because it was significantly deeper and; therefore, less accessible than the other locations.

At all sampling locations fish were plentiful and appeared to be in good health, but were generally small and wary of divers. Larger individuals appeared to be heavily fished from the reefs around Vieques.

At the Mosquito Pier location, the remains of a freshly butchered green sea turtle (Chelonia mydas) were found. The turtle was quite small, definitely immature, and all that was left was the neatly cut away plastron, still attached to the foreflippers. Since the green sea turtle is an endangered species and is protected by federal law, the finding was reported to the Puerto Rico Department of Natural and Environmental Resources (DNER). While green sea turtles are a common inhabitant of seagrass beds throughout the Caribbean, they were conspicuously absent from the seagrass beds during the dives conducted for this study.

Location 1

The first unnamed reef visited on the north shore of the LIA was a small, shallow, well developed patch reef, labeled "North LIA 1" by field personnel. The reef appeared to be in good health, with a diverse population of corals and fish. The reef was shallow, from 5 meters to emergent, composed of large head corals (e.g., Montastrea sp. and Diploria sp.) and soft corals (e.g., gorgonians and sea fans), with a lot of structure (hiding places for reef organisms) (see Pictures 22, 23, and 24). The reef was surrounded by a halo and a healthy turtle grass bed. Conch were collected in the turtle grass, but were very sparse and only a few legal sized specimens were found. Unexploded ordnance was visible in the seagrass bed.

The second unnamed reef visited on the north shore of the LIA was a small barrier type reef, extending east to west for approximately 250 meters from a small island, and labeled "North LIA 2" by field personnel. The reef was shallow, to a depth of 7 meters, but had relatively high relief (3 to 5 meters off the sand) and good structure. The reef appeared to be in good health, with a diverse population of corals and fish. On the shore side of the reef, there was a narrow halo and a healthy turtle grass bed. No ordnance was observed in this area. Field personnel did not dive on the seaward side of the reef.

Location 2

The first section of the former Navy vessel visited, on the south shore of the LIA, is in approximately 8 meters of water and is home to a diverse population of fish, all of which appeared to be healthy. One section had high relief (approximately 5 meters off the sand) but the smooth sides and top offered no habitat. Nonetheless, dozens of several different kinds of fish were seen inside that section. The other sections ranged from flat plates to broken sections with a lot of structure for fish habitat. There was a spotty distribution of small head corals (e.g., Montastrea sp., and Diploria sp.) growing on the surfaces of the wreck exposed to current and sunlight. All corals observed appeared to be in good health. The wreck was surrounded by a large halo and a healthy turtle grass bed. Unexploded ordnance was a common sight around the wreck and in the surrounding seagrass bed.

The second portion of the vessel was a large structure which provided habitat for fish. Located approximately 100 meters southeast of the first portion, it is also in about 8 meters of water and is home to a diverse population of apparently healthy fish. The ship offered high relief (approximately 5 to 6 meters off the sand), with a lot of structure for fish habitat. There was a spotty distribution of small, healthy head corals growing on the surfaces of the wreck which were exposed to current and sunlight (see Pictures 25 and 26). The wreck was surrounded by a large halo and a healthy turtle grass bed. Conch were collected in the halo area and the seagrass bed. Unexploded ordnance was a common sight around the wreck and in the surrounding seagrass bed.

Location 3

The first reef visited on the south shore near the town of Esperanza was Bucky Reef. The reef was approximately 18 meters deep and had high relief (5 to 7 meters off the sand), with a lot of structure. The reef appeared to be in good health, with a diverse population of both corals and fish. The top of the reef was mainly soft corals (e.g., gorgonians and sea fans) interspersed with small head corals, while the base of the reef had numerous holes and undercut ledges for fish habitat. The ocean bottom near the reef was coarse sand with some coral rubble.

The second reef visited on the south shore near Esperanza was Patti Reef. The reef was approximately 10 meters deep and had a lower profile than Bucky Reef, with isolated head corals and less structure. There were many healthy soft corals and a wide diversity of fish. The reef was spread out over a large area and the ocean bottom was sand and rubble. Most of the fish observed on this reef were small, probably a result of the lack of hiding places suitable for use as refuge from predators.

The third area visited was the seagrass area inshore of Arena Reef, in approximately 15 meters of water. The seagrass bed was sparse, but there were quite a few large conch present.

Location 4

The first reef visited on the north shore near the town of Isabel Segunda was an unnamed reef that field personnel labeled "Isabel 1." The reef was shallow, from 5 meters to emergent, and it was similar in structure to Patti Reef, with a low profile and many healthy soft corals. The isolated head corals and numerous fish all appeared healthy. The reef was spread out over a large area and the bottom was sand and rubble (see Picture 27).

The second reef visited on the north shore near the town of Isabel Segunda was also unnamed, and was called "Isabel 2" by field personnel. The reef was growing on a gradual slope that rose from a sand flat at approximately 13 meters deep to approximately 3 meters deep. The sand flat demonstrated the typical halo away from the reef into a seagrass bed. The reef had a lot of structure and supported a diverse, healthy population of hard and soft corals and fish (see Pictures 28 and 29).

The third location visited on the north shore near the town of Isabel Segunda was Mosquito Pier. The pier is a large earthen structure extending approximately one-half mile to the north from land. In order to accommodate large vessels a dock extends to the west, near the end of the pier, into approximately 13 meters of water. Diving to collect fish was limited to the area under the dock. The dock had a lot of structure, mostly concrete rubble, at its origin and supported a large population of small fish. Toward the end of the dock, there was very little bottom structure except for the dock pilings. There were no hard corals present, though the pilings displayed nearly complete encrustation with a diverse population of invertebrate and plant life.

Location 6

The unnamed reef visited on the west end of the island was southwest of the Monte Pirata Conservation Zone, labeled "West End" by field personnel, and was in 20 meters of water. The reef was a spur and groove type reef with low relief (less than 3 meters off the sand), but had a lot of structure for fish. Spur and groove reefs are characterized by a series of long (100 meters), usually narrow (7 meters wide) coral spurs, with a narrow (7 meters wide) bare sand channel between each spur. The reef had diverse, apparently healthy, populations of corals and fish. The tops of the spurs had many soft corals and small head corals, and the bottom of the spurs had many small holes and undercuts for fish habitat.

Conch were collected from a healthy turtle grass bed approximately 500 meters northeast of the reef in approximately 7 meters of water. Conch were plentiful, but most visible animals were below legal size.



 
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