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Suggests a greater production of coralline sand (rather than slower Halimeda growth) results from a marked acceleration of bioerosion of abundant dead reefs in the area. -from Authors
The 107-yr growth history of a massive coral Solenastrea bournoni from Florida Bay was reconstructed with X-ray imagery from a single 4 in. diameter (10 cm) core that penetrated the exact epicenter of the 95.3 cm high colony. Growth increments totalled 952.9 mm, averaging 8.9 mm/yr over the life of the coral. Growth rate trends in the Florida Bay coral were compared to those in a Montastraea annularis of similar age from a nearby patch reef on the Atlantic Ocean side of the Florida Keys. It was concluded that growth rate, at least in these specimens, is a questionable indicator of past hurricanes and freezes. There does appear to be, however, a possible cause-and-effect relationship between major man-induced environmental perturbations and a prolonged reduction in growth rate in each coral's growth record. -from Authors
Ecologic studies of benthic Foraminifera in Florida Bay indicate that 1) the bay is a specialized restricted platform interior environment; 2) its fauna is divisible into 3 subfaunas: nearshore, mudbank, and "lake', 3) substrate, currents, wave intensity, and wave direction affect local distribution but do not alter regional patterns; and 4) faunal assemblages rather than individual species of Foraminifera are diagnostic environmental indicators as many species range over several faunal zones. -from Authors
Examination of 16 artificial reef structures in depths ranging from 30-120m indicated that the highest numbers of fish are found around reefs in water shallower than 46m. Fewer fish, especially those with tropical coral reef affinities, <46m was probably caused by a thermocline. Algae and reef community encrusters, abundant on shallower structures, were absent below 46m. Structures that penetrated above the thermocline, such as upright oil rigs and a hopper barge, were also effective reefs. The open structure and high profile of the rigs enhance their use as artificial reefs by providing a range of well-aerated habitats. Greatest diversity and numbers of fish were observed at the Miami sewer outfall. -from Authors
Synonymies, diagnoses, descriptions, illustrations, and spot distribution maps are given for ten species of Opistognathus, including all western Atlantic species that have a cirrus on their anterior nostrils. Three deep-water species lacking nasal cirri are also treated, including O. leprocarus n. sp. (Bahamas and Lesser Antilles), O. melachasme (Yucatan), and O. nothus n. sp. (North Carolina, Gulf of Mexico and Cuba); the latter two species were originally thought to represent different sexes of the same species. The O. macrognathus species group is diagnosed primarily by having sexually dimorphic jaws and sexually dichromatic maxillary markings, and includes the eastern Pacific O. scops and the following five western Atlantic species: O. macrognathus (Florida, Gulf of Mexico, and Bahamas to northern South America), O. brasiliensis n. sp. (southern Brazil), O. cuverii (southern Brazil), O. robinsi n. sp. (South Carolina, Florida, Bahamas, and Gulf of Mexico), and O. signatus n. sp. (Nicaragua, Panama, and northern South America). Opistognathus robinsi and O. signatus are very similar morphologically and here recognized as allopatric sister-species but the possibility exists that their disjunct continental distributions may be a collecting artifact. The broadly distributed and shallow-water species Opistognathus whitehurstii and O. maxillosus are superficially similar to some members of the O. macrognathus species group, including having cirri on their anterior nostrils, but differ most obviously in having non-sexually dimorphic jaws and more numerous cephalic sensory pores. An identification key is provided for all known western Atlantic species of Opistognathus.
In October 1988, a cruise ship dropped its anchor on a coral reef in Virgin Islands National Park, St. John, creating a distinct scar roughly 128 m long and 3 m wide from a depth of 22 m to a depth of 6 m. The anchor pulverized coral colonies and smashed part of the reef framework. In April 1991, nine permanent quadrats (1 m2) were established inside the scar over a depth range of 9 m to 12.5 m. At that time, average coral cover inside the scar was less than 1%. These quadrats were surveyed again in 1992, 1993, 1994, 1995 and 1998. Recruits of 19 coral species have been observed, with Agaricia agaricites and Porites spp. the most abundant. Quadrats surveyed outside the scar in June 1994 over the same depth range had a higher percent coral cover (mean = 7.4%, SD = 4.5) and greater average size (maximum length) of coral colonies than in quadrats inside the damaged area. Although coral recruits settle into the scar in high densities, live coral cover has not increased significantly in the last 10 yrs, reflecting poor survival and growth of newly settled corals. The relatively planar aspect of the scar may increase the vulnerability of the recruits to abrasion and mortality from shifting sediments. Ten years after the anchor damage occurred, live coral cover in the still-visible scar (mean = 2.6%, SD = 2.7) remains well below the cover found in the adjacent, undamaged reef.
The linear chain transect method and videography were used to quantify the percent cover by corals, macroalgae, gorgonians, other living organisms, and substrate along permanent transects on two fringing reefs off St. John. Both methods were used simultaneously on Lameshur reef in November 1998, and on Newfound reef in March and October 1998. Hurricane Georges passed over St. John in September 1998, and a severe coral bleaching episode began the same month. Both methods gave remarkably similar values for coral cover, while the video method gave consistently higher values for gorgonians and macroalgae. The most dramatic difference was in the quantification of bleaching. At Newfound, the chain method indicated 13.4% (SD = 14.1) of the coral tissues were bleached and the video method, 43.4% (SD = 13.0). Corresponding values at Lameshur were 18.1% (SD = 22.3) and 46.5% (SD = 13.3). Although hurricane damage was conspicuous at Newfound reef, neither method showed significant changes in coral cover or other categories as a result of the storm.
The reproductive biology of Cheilopogon melanurus (Valenciennes, 1847) was examined off North Carolina during the summers of 1991–1992 and 1999–2003. Specimens were collected using a small mesh neuston net and dip nets. A spawning event, the first observation of mating behavior for this species, was recorded off Cape Fear, North Carolina, on 19 August 2003. It was considered to be a spawning event due to: 1) unusual coloration of both sexes, 2) unusual swimming behavior of both sexes, and 3) ready release of gametes by both sexes upon capture. The spawning event occurred in the presence of small clumps of floating Sargassum , but the fish did not appear to use the algae. Over all collections, female gonadosomatic indices were highest in June and July, but mature females were collected each month (June, July, and August). The overall female to male sex ratio did not vary significantly from 1:1. Number of ova increased with increasing fish size, but the relationship was not strong. Our data indicate a spawning season of at least June through August off North Carolina due to high female gonadosomatic indices, large egg diameters, presence of egg filaments, presence of spent females in July and August, and presence of small juveniles (≤ 25 mm) in July and August. This is the first report of single pair spawning for this family; other species reportedly spawn in large aggregations.
This study was conducted to determine the distribution, abundance, and demography of a wood boring isopod, Sphaeroma terebrans Bate, 1866, within the prop roots of the red mangrove, Rhizophora mangle L., in eight sites within Tampa Bay, Florida. Sphaeroma terebrans in Tampa Bay displayed reproductive activity year-round and bay-wide synchrony in their density pattern. On average approximately 60% (range: 25%-86%) of the intertidal aerial roots surveyed were occupied by S. terebrans. Although infestation levels by S. terebrans in Tampa Bay were similar to that of more tropical regions, the distribution of S. terebrans was not continuous throughout the study sites. A substantially higher occurrence and density of S. terebrans was found in the northern compared to more southern study sites within the Bay. Additionally, some seemingly suitable areas of the bay (i.e., Pinellas Point, Skyway, Fort Desoto) were actually unoccupied on some dates. Although sites differed in the frequency with which roots were attacked, the density of burrows and isopods in an occupied root was similar, with most attacked roots containing 3-5 burrows. The results of a transplantation experiment indicated that neither abiotic factors nor substrate quality limit the burrowing capabilities or survival of adult S. terebrans in the areas where they are absent. Instead, dispersal limitation, linked with differential juvenile survival, most likely controls isopod distribution and abundance within Tampa Bay.
We investigated the effects of mangrove cutting on fish assemblages in Twin Cays, Belize, in two habitat types. We conducted visual censuses at two sites in adjoining undisturbed/disturbed (30%–70% of shoreline fringe removed) sub-tidal fringing Rhizophora mangle Linnaeus, 1753. Observers recorded significantly more species and individuals in undisturbed sites, especially among smaller, schooling species (e.g., atherinids, clupeids), where densities were up to 200 times greater in undisturbed habitat. Multivariate analyses showed distinct species assemblages between habitats at both sites. In addition, extensive trapping with wire minnow traps within the intertidal zone in both undisturbed and disturbed fringing and transition (landward) mangrove forests was conducted. Catch rates were low: 638 individuals from 24 species over 563 trap-nights. Trap data, however, indicated that mangrove disturbance had minimal effect on species composition in either forest type (fringe/transition). Different results from the two methods (and habitat types) may be explained by two factors: (1) a larger and more detectable species pool in the subtidal habitat, with visual "access" to all species, and (2) the selective nature of trapping. Our data indicate that even partial clearing of shoreline and more landward mangroves can have a significant impact on local fish assemblages.
[No abstract available]
We mapped and briefly describe the surficial geology of selected examples of shelf-edge reefs (50–120 m deep) of the southeastern United States, which are apparently derived from ancient Pleistocene shorelines and are intermittently distributed throughout the region. These reefs are ecologically significant because they support a diverse array of fish and invertebrate species, and they are the only aggregation spawning sites of gag ( Mycteroperca microlepis ), scamp ( M. phenax ), and other economically important reef fish. Our studies on the east Florida shelf in the Experimental Oculina Research Reserve show that extensive damage to the habitat-structuring coral Oculina varicosa has occurred in the past, apparently from trawling and dredging activities of the 1970s and later. On damaged or destroyed Oculina habitat, reef-fish abundance and diversity are low, whereas on intact habitat, reef-fish diversity is relatively high compared to historical diversity on the same site. The abundance and biomass of the economically important reef fish was much higher in the past than it is now, and spawning aggregations of gag and scamp have been lost or greatly reduced in size. On the west Florida shelf, fishers have concentrated on shelf-edge habitats for over 100 yrs, but fishing intensity increased dramatically in the 1980s. Those reefs are characterized by low abundance of economically important species. The degree and extent of habitat damage there is unknown. We recommend marine fishery reserves to protect habitat and for use in experimentally examining the potential production of unfished communities.
Long-term annual growth rates were determined for 25 Montastrea annularis colonies at eight reef sites in Biscayne National Park, Florida. X-radiographs of slabbed coral cores revealed chronologies that averaged 113.5 years in length with a range of 40 to 242 years. A total of 2,837 annual growth increments were identified and measured. Dating of density bands was verified by visually crossdating fluorescent bands within the coral skeleton. Average accretion rates of individual colonies varied from 5.0 mm·yr −1 in the northernmost sector of the Park to 11.3 mm·yr −1 in the southernmost sector. Long-term growth rates of most corals in this study were greatest prior to about 1950 except for a major, 3–5 year, decline in the growth record of older corals centered around 1878. Waxing and waning coral growth rates are discussed in relation to natural and anthropogenic perturbations that impact this high latitude reef ecosystem. Attention is drawn to nutrients from sewage outfalls as a possible contributing factor to observed growth rate decline since 1950.
The tilefish, Lopholatilus chamaeleonticeps , constructs burrows in carbonate sediments off the central east coast of Florida at similar temperatures (8.6-15.4°C) and in similar sediment textures (high proportion of silts and clays) to conspecifics in the Mid-Atlantic Bight. The depths at which we observed tile fish off Florida (150-290 m), based on submersible observations and sidescan sonar operations during 1983 and 1984, were similar to those recorded in 1975-1977 (137-266 m) before the inception of the directed fishery. Both are similar to the range observed in the Mid-Atlantic Bight although tilefish there can be found at shallower and slightly deeper depths (80-305 m). The largest burrows off Florida (1.5-m diameter) were smaller than those observed in the Mid-Atlantic Bight (up to 5 m). The behavior of tile fish around the burrow and the invertebrates and fishes co-inhabiting the burrows off Florida are nearly identical to those in the Mid-Atlantic Bight. Despite the relatively narrow annual temperature range observed off Florida, abrupt changes in temperatures (+6°C) occurred over a 48-h period based on thermograph records. Our observations, and those of others from several areas along the U.S. east coast, suggest that this species probably constructs burrows throughout its geographic range, and that temperature and sediment composition largely determine its distribution. Exclusion experiments off Florida, along with prior removal experiments in the Mid-Atlantic Bight, indicate that tilefish construct and maintain the burrows.
The demersal fish fauna of Lophelia pertusa (Linnaeus, 1758) coral reefs and associated hard-bottom biotopes was investigated at two depth horizons in the northern Gulf of Mexico using a manned submersible and remote sampling. The Viosca Knoll fauna consisted of at least 53 demersal fish species, 37 of which were documented by submersible video. On the 325 m horizon, dominant taxa determined from frame-by-frame video analysis included Stromateidae, Serranidae, Trachichthyidae, Congridae, Scorpaenidae, and Gadiformes. On the 500 m horizon, large mobile visual macrocarnivores of families Stromateidae and Serranidae dropped out, while a zeiform microcarnivore assumed importance on reef "Thicket" biotope, and the open-slope taxa Macrouridae and Squalidae gained in importance. The most consistent faunal groups at both depths included sit-and-wait and hover-and-wait strategists (Scorpaenidae, Congridae, Trachichthyidae), along with generalized mesocarnivores (Gadiformes). The specialized microcarnivore, Grammicolepis brachiusculus Poey, 1873, appears to be highly associated with Lophelia reefs. The coral "Thicket" biotope was extensively developed on the 500 m site, but fish abundance was low with only 95 fish per hectare. In contrast to Lophelia reefs from the eastern the North Atlantic, the coral "Rubble" biotope was essentially absent. This study represents the first quantitative analysis of fishes associated with Lophelia reefs in the Gulf of Mexico, and generally in the western North Atlantic.
The first comprehensive evaluation of stream fauna in the Eastern Caroline Islands resulted from collections on Ponape, a 334-km- island having more than 40 streams, many of which arise along 700-m-high interior ridges. Field surveys centered on the Nanpil-Kiepw River below 170 m elevation, a bouldery reach with water of low mineral content and frequent surging flows. Faunal specimens were collected by electrofishing, rotenone treatment, netting, and hand picking. Discharge character of the Nanpil-Kiepw River is similar to but more extreme than that of other streams of Oceania with which it was compared. Drastic flow surges appeared to be a major factor affecting community structure. At least 44 faunal species were present, 36 of them representing taxons primarily of marine origin that are characteristic of oceanic islands: 15 fishes (5 families), 10 decapod crustaceans (3 families), and 11 snails (2 families). Larvae of aquatic moths were the only insects of significance. Four sicydiine gobies are new species possibly endemic to Ponape or the Eastern Caroline Islands. Based on numbers of species within prominent taxons and diadromous groups, Ponape’s faunal diversity exceeds that of Samoa, Guam, and Hawaii, but is lower than that of Palau. Similarities of Ponape's identified fish species to those of Palau suggest that Ponape was colonized from the west along the “Caroline conduit.”
Ten species of caridean shrimps, representing nine genera in five families, have been found in exposures of the marine water table at 28 islands from Hawaii to the western Indian Ocean. Synthesis of literature information and personal observations indicate that, as a group, these shrimps are characterized by red body pigment, reduced but pigmented eyes, euryhalinity, a proclivity for interstitial seawater in limestone or lava rock, generalized food requirements, and probable pre-Pleistocene origins. The shrimps have not been found in waters cooler than about 20°C. Species are often solitary, but as many as five are known to coexist. Six of the species have widely scattered populations, some as far apart as Hawaii and the Red Sea. Passive oceanic dispersal is endorsed as a general explanation for such apparently disjunct distributions. On the basis of an assumed primary habitat requirement of interstitial marine water, which could include that in shallow submerged rock as well as that in emergent (insular) rock, I hypothesize a much more cosmopolitan distribution of these shrimps in the Indo-Pacific Tropical Zone.
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