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Long Term Monitoring of a Deep-water Coral Reef: Effects of Bottom Trawling.
Abstract and Figures
The deep-water Oculina coral reef ecosystem is unique and exists solely off the east coast of central Florida. Oculina varicosa forms azooxanthellate colonies up to 2 m in diameter which coalesce into dense thickets on 20-m tall mounds that are thousands of years old. Recently restored videotapes that were made in the 1970s with the Johnson-Sea-Link submersibles show large breeding aggregations of grouper associated with the coral habitat. Historical photographic surveys provide evidence of the status and health of the reefs prior to heavy fishing and trawling activities of the 1980s and 1990s. Recent quantitative analyses by point count of photographic images reveal drastic loss of live coral cover between 1975 and present. Submersible and ROV surveys conducted from 2001 to 2006 suggest that much of the Oculina habitat has been reduced to rubble by bottom trawling which unfortunately is a trend for deep-water reefs worldwide. In 1984, the Oculina reefs were the first deep-water coral reefs in the world to be designated a marine protected area (MPA). Unfortunately, the northern two-thirds of the reef system remained unprotected and was legally open to bottom trawling until the year 2000 when the boundaries were expanded to 1029 km 2 (300 nm 2) from the original 315 km 2 (92 nm 2). However, portions of the original reserve are still healthy and signs indicate improving grouper populations. In 2006, a high resolution multibeam map was completed which details the hundreds of pinnacles and ridges making up the reef system. Many new reef features were discovered both inside and outside the designated MPA.
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... Because of the high diversity of associated invertebrates, this habitat is also a feeding ground for groupers (red grouper, warsaw grouper), jacks (greater amberjack, almaco jack), sharks (tiger shark Galeocerdo cuvieri, scalloped hammerhead shark Sphyrna lewini), snappers (red snapper, gray snapper), and black sea bass (Gilmore and Jones, 1992;Reed, 2002b). The location of this habitat is also on the path of highly migratory species including king mackerel, Spanish mackerel, wahoo, and little tunny (Reed, 2002b) Studies in a nearby area within the Oculina Banks indicated that these highly biodiverse and spawning-critical habitats have been extensively degraded and reduced to rubble by destructive fishing practices (Koenig et al., 2000;Reed et al., 2007). Evidence of the threats posed by bottom trawling is unmistakable on the Cape Canaveral Pinnacle reef, which has been destroyed progressively over the past 25 years (Reed et al., 2005;Reed et al., 2007). ...
... The location of this habitat is also on the path of highly migratory species including king mackerel, Spanish mackerel, wahoo, and little tunny (Reed, 2002b) Studies in a nearby area within the Oculina Banks indicated that these highly biodiverse and spawning-critical habitats have been extensively degraded and reduced to rubble by destructive fishing practices (Koenig et al., 2000;Reed et al., 2007). Evidence of the threats posed by bottom trawling is unmistakable on the Cape Canaveral Pinnacle reef, which has been destroyed progressively over the past 25 years (Reed et al., 2005;Reed et al., 2007). In 1976 the Cape Canaveral Reef was colonized by live Oculina of ~1 m tall on the flanks covering 25% of the reef (17% coral rubble) and dominated by several fish species including snowy grouper, greater amberjack, butterflyfish, blue angelfish (Holacanthus bermudensis), damsels, and wrasses. ...
... In 1976 the Cape Canaveral Reef was colonized by live Oculina of ~1 m tall on the flanks covering 25% of the reef (17% coral rubble) and dominated by several fish species including snowy grouper, greater amberjack, butterflyfish, blue angelfish (Holacanthus bermudensis), damsels, and wrasses. By 2001, the same reef had been reduced to unconsolidated dead coral rubble, and the fish assemblage was reduced to amberjack and few small reef fish (Reed et al., 2007). ...
... 62.5 %) are being fished at their maximum sustainable yield or above their maximum reaching unsustainable levels (FAO, 2022;Papaconstantinou and Farrugio, 2000;Tsikliras et al., 2015). Moreover, bottom trawlers disturb and destroy seafloor habitats in their path, including seagrasses, coral reefs, or rock gardens, considered key habitats for multiple species (Stiles et al., 2010;Reed et al., 2007). Bottom trawling can also strongly modify seafloor morphology because of the resuspension and removal of a large amount of sediment by the action of wires, otter doors, sweeps, and nets (Palanques et al., 2006;Puig et al., 2012). ...
In the context of marine conservation, trawl fishing activity is the most important ecosystem stressor in demersal Mediterranean waters. Limited management measures in bottom trawling have caused deep-sea stocks of the iconic Norway lobster Nephrops norvegicus to decrease over the last decade. This crustacean acts as an umbrella species for co-existing megafauna. Here, we used non-invasive Remote Operated Vehicle (ROV) video-surveys to investigate the status of a pilot deep-sea no-take reserve implemented in the northwestern Mediterranean by quantifying demographic indicators of Norway lobsters and the co-existing benthic community, seafloor restoration, and the presence of marine litter. The results revealed that in the no-take reserve the Norway lobster stock showed higher abundance and biomass, and slightly larger body sizes than the control area without fishing prohibition. Some taxa, such as the fishes Helicolenus dactylopterus and Trigla lyra and anemones of the family Cerianthidae, had increased in abundance. We also observed that all trawling marks were smoothed and most of the seafloor was intact, clear indicators of the recovery of the muddy seafloor. The accumulation of marine debris and terrestrial vegetation was similar in the no-take reserve and the fished area. On the basis of the results of this study, we suggest that the use of no-take reserves might be an effective measure for recovering the Norway lobster stock, its co-existing megafauna community, and the surrounding demersal habitat. We also suggest that ROV video-survey might be a useful, and non-invasive method to monitor megafauna and seafloor status in protected deep-sea environments.
... Bottom trawling represents one of the main threats to benthic ecosystems (Clark et al., 2016;Hall-Spencer, Allain, & Fossa, 2002), resulting in a severe oversimplification of benthic communities (Reed, Koenig, Shepard, & Gilmore, 2007;Thrush & Dayton, 2002;Watling & Norse, 1998). However, in rocky areas with complex topography inaccessible to trawling, artisanal fishing can also jeopardise the integrity of benthic ecosystems (Angiolillo & Canese, 2018;Sampaio et al., 2012). ...
Gorgonians dwelling on the Mediterranean continental shelf are among the most frequent fishing bycatch taxa. These species display several traits, such as long lifespans and slow growth, which make them very vulnerable to the impacts caused by fishing activities with far‐reaching and long‐lasting effects.
Hence, restoration and mitigation actions are crucial to enhance and speed up the natural recovery of damaged cold‐water coral gardens. Given the growing concern to develop effective and affordable restoration actions, the present study aims to propose and technically validate a new large‐scale and cost‐effective restoration method.
This technique, named ‘badminton method', consists of attaching bycatch Eunicella cavolini colonies to cobble supports and returning them to the continental shelf by gently throwing the gorgonian transplants directly from a boat.
Two consecutive field experiments were conducted in order to find the best cobble type support and gorgonian size to be used: first, to evaluate the landing efficiency of gorgonian transplants at different depths (from 5 to 30 m) and second, to evaluate their capability to maintain a correct position over time.
Natural cobbles with large gorgonians attached were the best option. Field results and modelling approaches suggest that the transplants would correctly land on the continental shelf seabed in a predicted area of around 60 m ² . Moreover, they would successfully maintain an upright position ensuring gorgonian survival over time.
The success of this method highlights the feasibility of large‐scale and low‐cost restoration actions with promising results for the conservation and recovery of cold‐water coral gardens.
... Recentemente os drones ganharam atenção devido ao grande número de mortes de civis provocadas por ataques dos Estados Unidos utilizando UAV's no Afeganistão e no Iraque (Weber, 2009). É crescente o número de projetos científicos que estão utilizando drones em pesquisas sobre agricultura (Costa et al., 2012), ambientes marinhos e oceânicos (Reed et al., 2007) e florestas tropicais (Koh & Wich, 2012). Protei se difere dessas iniciativas ao utilizar a apropriação crítica de tecnologias e o conhecimento ecológico local para desenvolver pesquisas, processos e produtos socioambientais colaborativos sob licenças livres de uso, compartilhamento e modificação. ...
This paper identifies and evaluates the Points of Culture in the city of Santos, Sao Paulo State, aiming to detect possibilities for future developments of experimental laboratories as nuclei for co-management. The survey, which used as source the Network Catalog of Culture Points of Sao Paulo State to identify points (BRAZIL 2012), was carried out between June and July 2012. It was identified two Points of Culture: the “Project Parcel”, located in the continental area, and the “Station of Citizenship and Culture”, in the insular area of Santos. Both have potential to develop experimental activities related to the theme and could subsidize activities of co-management.
Underwater Pulse Position Modulation (PPM) transmission uses acoustic pulses since these allow communication, remote control of underwater vehicles and positioning estimation, this last when more than one detector is present by using only one technology, that is, the same transmission module. On the other hand PPM pulses are difficult to detect since they carry information on signal delays, so assuring reliable information delivery both in shallow and deep sea channels may be considered a timely challenge due to strong multipath and other interference sources/causes giving rise to signal fluctuation and high noise level. This paper proposes a transceiver architecture characterized by a signal analyzer and an
adaptive detection based on the channel features. The signal analysis is based on the Wigner-Ville Transform (WVT) that converts a one-dimensional signal into an image. Edge detection procedures performed on the obtained image so to discover the interference features and understand the main characteristics of multipath with their adverse effects on detection of pulse position information have been taken into account. Basing on this, Maximal Ratio Combining (MRC) and Equal Gain Combining (EGC) for RAKE reception and truncated channel equalization have been considered. Numerical results showing the ability of this the proposed transceiver to detect pulses in the presence of multipath, interference generated by external acoustic sources have been carried out also by taking into account
the estimation error effects and by comparing the actual performance with ideal cases. Finally field tests corroborate the reliability of the proposed approach.
For decades remotely-operated vehicles (ROVs) have been designed and implemented in various size and shape. Among them, very small-sized ROV which is called micro ROV has the working range with tens of meters and takes the place of divers. In this paper, we develop a micro ROV operating not by umbilical cable which is troublesome for movements but by wireless acoustic communication. The micro wireless ROV is designed to conduct the commands of movement and measurement from a remote user and to report the result. Experiments in water tanks have verified functional operations of the vehicle and shown the feasibility for applications.
The growth form of the scleractinian ivory tree coral Oculina varicosa (also known as fused ivory tree coral) that occurs on the shelf edge off Florida's eastern coast is unique for this species. Here, the branching coral colonies coalesce into thickets supporting high vertebrate and invertebrate biodiversity and high densities of economically important reef fish. In 1984, the South Atlantic Fishery Management Council took the first step to protect the area from trawling and other disruptive bottom activities. Despite these protective measures, however, there is evidence that trawling has damaged previously intact coral habitat. In this paper, we describe results from mapping studies conducted in 2001 and improvements to reef fish populations that have occurred in the last few years. We find that less than 10% of the area contains intact Oculina coral thickets, which we continue to attribute primarily to trawling. In addition, we find increased grouper density and male abundance inside the protected area, suggesting population recovery, and the appearance of juvenile speckled hind Epinephelus drummondhayi (family Serranidae), suggesting nursery function for this and possibly other commercially important species.
In 1984, a portion of the deep-water Oculina coral reef ecosystem off eastern Florida was protected as the Oculina Habitat Area of Particular Concern (OHAPC), prohibiting bottom trawls, longlines, dredges, and anchors. Unfortunately, the northern two thirds of the reef system remained open to these gear until 2000 when the OHAPC boundaries were expanded to 1029 km2. In the 1970s, the Oculina reefs were teeming with large spawning aggregations of grouper and snapper. By the early 1990s, commercial and recreational fishing had decimated the fish populations, and the coral had been severely impacted by bottom trawling for rock shrimp. Historical photographic transects, taken in the 1970s with the Johnson-Sea-Link sub-mersibles, provide crucial evidence of the status and health of the reefs prior to heavy fishing and trawling activities. Quantitative analyses of photographic images by point count reveal drastic loss of live coral cover between 1975 and 2001. Six coral reef sites had nearly 100% loss of live coral, whereas only two reefs which were within the boundaries of the original OHAPC since 1984 survived and were not impacted by trawling. Management and conservation plans for deep-sea coral reef ecosystems worldwide must be based on sound scientific understanding as well as adequate surveillance and enforcement; this study will help build a foundation for this understanding.
Deep-water Oculina coral reefs, which are similar in structure and development to deep-water Lophelia reefs, stretch 167 km (90 nm) at depths of 60–100 m along the eastern Florida shelf of the United States. These consist of
numerous pinnacles and ridges, 3–35 m in height, that are capped with thickets of living and dead coral, Oculina varicosa. Extensive areas of dead Oculina rubble are due in part to human impacts (e.g., fish and shrimp trawling, scallop dredging, anchoring, bottom longlines, and
depth charges) but also may be due in part to natural processes such as bioerosion, disease, or global warming. In the 1970s,
the reefs were teeming with fish. By the early 1990s, both commercial and recreational fisheries had taken a toll on the reefs,
especially on the coral habitat and populations of grouper and snapper. In 1984, 315 km2 (92 nm2) was designated the Oculina Habitat of Particular Concern (OHAPC), prohibiting trawling, dredging, bottom longlines and anchoring, and establishing the
first deep-sea coral marine protected area in the world. In 2000, the Oculina Marine Protected Area (MPA) was expanded to 1029 km2 (300 nm2). Despite these protective measures, manned submersible and ROV observations in the Oculina MPA between 1995 and 2003 suggest that portions of the coral habitat have been reduced to rubble since the 1970s, grouper
spawning aggregations may be absent, and illegal trawling continues. This paper is a review of the results of the mapping,
habitat characterization, and fish surveys from the early historical studies (1960–1980s) to the more recent surveys (1995–2003).
Soft rubber tumbling barrels, some with screen windows, were used to simulate natural abrasion of coral branches. -from Authors
Subsurface water temperature data are combined with time series of coastal winds and mid shelf currents to investigate seasonal upwelling in shelf waters off South Florida's Atlantic coast. Data from the summer of 1978 indicate that cool water moved onto the shelf by mid June and remained there until early September. A time series of near-bottom temperatures from inner shelf waters indicates three major periods of cooling, lasting over time intervals of from one to three weeks. Water temperatures decrease from 3° to 7°C. More transient cooling events are recorded throughout the record. The effect of up-welling is to decrease coastal water temperatures to levels characteristic of early winter or late spring. The coherence of near-bottom temperatures recorded over the inner shelf and just beyond the shelf break is low, and inner shelf near-bottom temperatures are not significantly coherent with either the longshore or cross-shelf component of the windstress. It is therefore unlikely that Ekman dynamics play a major role in driving upwelling along this part of the coast. Mid shelf, near-bottom temperatures are coherent with the longshore current over time scales in excess of about two days. This suggests that upwelling occurs as a dynamic adjustment to variations in the Florida Current.
Eighty topographic transects were made off the central Atlantic coast of Florida between Cape Canaveral and Palm Beach, November, 1973 to September, 1974, aboard the Research Vessel Gosnold. Profiles obtained with a precision depth recorder indicated the presence of continuous and discontinuous structures on the outer continental shelf and at the shelf-slope break. Most conspicuous was a band of pinnacles, benches, mounds and troughs extending north from Fort Pierce to Cape Canaveral, Florida, and a massive mound occurring off St. Lucie Inlet. These occurred under the western edge of the Florida Current and along the edge of the continental shelf (about 80° W). From Fort Pierce southward to Palm Beach, these structures almost disappear.
Dredgings in two selected areas of pronounced vertical profile, and preliminary visual and photographic observations made with the Johnson-Sea-Link I submersible, confirmed the existence of rich, sessile and motile invertebrate assemblages and fish populations associated with exposed limestone bedrock, talus, and the scleractinian coral Oculina varicosa.
Color variants and behavior of scamp, Mycteroperca phenax, and gag, M. microlepis, are described from 64 submersible dives made on reef structures at depths between 20 and 100 m off the east coast of Florida from February 1977 to September 1982. These dives yielded 146 h of observations augmented with video and 35 mm photography. Both species display a variety of color phases associated with social behavior. They are expressed in each case by an aggressive, dominant territorial individual which displays to a group of smaller subordinates. Social hierarchy is evident in both species, with the alpha individual being a male in the gag and of undetermined sex in the scamp. Although actual spawning was not documented, hierarchical behavior and displays are interpreted as courtship associated with spawning activity. Courtship is further implied based on the similarity of these behaviors to those recorded for a variety of other fishes including serranids. Scamp appear to prefer habitats characterized by maximum structural complexity, such as living Oculina coral reefs, at depths between 70 and 100 m. The gag is a larger species and less dependent on live coral habitats. The significance of the social behavior in illuminating possible functions of protogyny and polygyny in M. phenax and M. microlepis is discussed. Documentation of complex social hierarchies in scamp and gag may have an impact on fishery management in that successful reproduction may prove dependent upon a wide variety of behavioral factors related to the role of individual fish in spawning hierarchies.
Data on the distribution and growth-form of the scleractinian Oculina varicosa were compiled from 135 submersible dives with the Johnson-Sea-Link submersibles and 57 dredge and trawl records by the R/V Gosnold and R/V Aquarius. A deep-water form of O. varicosa, lacking zooxanthellae, was found in depths of 50 to 100 m off central eastern Florida. These colonies are arborescent with highly anastomosed, irregular dendritic branches. Over 50 sites were located at which living colonies of O. varicosa from 0.25 to 2 m diameter occur either singly or as sparsely scattered groups. Nine areas were found with massive thickets of contiguous colonies up to 2 m in height. Extensive banks of Oculina thickets were found at five locations. The banks have a relief of 17 to 24 m and steep slopes of 30-45°, especially on the south side which faces into the Florida Current. The structure of these thickets and banks is very similar to deep-water Lophelia prolifera banks. Temperatures on the Oculina banks ranged from 7.5 to 26.5°C and had a yearly mean of 15°C.
Expeditions from 1999 to 2004 for biomedical research explored various deep-sea coral ecosystems (dSCE) off the southeastern U.S. (Blake Plateau, Straits of Florida, and eastern Gulf of Mexico). Habitat and benthos were documented from 57 dives with human occupied submersibles and three with a remotely operated vehicle (ROV), and resulted in ∼100 hrs of videotapes, 259 in situ digital images, 621 museum specimens, and > 400 microbial isolates. These were the first dives to document the habitat, benthic fauna, and fish diversity of some of these poorly known deep-water reefs. Fifty-eight fish species and 142 benthic invertebrate taxa were identified. High-definition topographic SEABEAM maps and echosounder profiles were also produced. Sites included in this report range from South Carolina on the Blake Plateau to the southwestern Florida slope: 1) Stetson Lophelia reefs along the eastern Blake Plateau off South Carolina; 2) Savannah Lophelia lithoherms along the western Blake Plateau off Georgia; 3) east Florida Lophelia reefs, 4) Miami Terrace escarpment in the Straits of Florida; 5) Pourtalès Terrace off the Florida keys; and 6) west Florida Lophelia lithoherms off the southwestern Florida shelf in the Gulf of Mexico. These are contrasted with the azooxanthellate deep-water oculina reefs at the shelf-edge off central eastern Florida. The fisheries and biopharmaceutical resource potential of these deep-water habitats remain relatively unknown. Although these habitats are not currently designated as marine protected areas (MPAs) or coral habitat areas of particular concern (HAPCs), they are ecologically diverse, vulnerable to physical destruction, and irreplaceable resources. Activities involving bottom trawling, pipelines, or oil/gas production could negatively impact these reefs. National Oceanic and Atmospheric Administration (NOAA) Fisheries and the South Atlantic Fishery Management Council are currently developing priority mapping sites of the dSCEs within this region, and these data may provide potential targets for new MPAs and HAPCs.
Two types of deep-water coral bioherms occur off the coast of southeastern United States: Oculina and Lophelia/Enallopsammia. The deep-water Oculina bioherms form an extensive reef system at depths of 70–100 m along the shelf edge off central eastern Florida. These reefs are comprised of numerous pinnacles and ridges, 3–35 m in height. Each pinnacle is a bank of unconsolidated sediment and coral debris that is capped on the slopes and crest with living and dead colonies of Oculina varicosa, the ivory tree coral. In comparison, deep-water reefs of Lophelia pertusa and Enallopsammia profunda corals occur at depths of 500–850 m (maximum 150-m relief) along the base of the Florida-Hatteras slope in the Straits of Florida. On the western edge of the Blake Plateau off South Carolina and Georgia, 54-m high banks of Enallopsammia and Lophelia occur at depths of 490–550 m, whereas on the eastern edge of the plateau the reefs form structures 146 m in height and at depths of 640–869 m. The geomorphology and functional structure of both the Oculina and Lophelia reefs are similar. North of Little Bahama Bank, at depths of 1000–1300 m, a region of bioherms is dominated by the coral Solenosmilia sp.; Lophelia is reportedly absent. This paper summarizes 25 years of submersible studies on the deep-water Oculina reefs, describes submersible reconnaissance of deep-water Lophelia reefs off the southeastern United States, and contrasts these types of bioherms with the deep-water lithoherms in the Straits of Florida west of the Bahamas.