Large Reef Research Articles

Sabellaria jeramae, a new species (Annelida: Polychaeta: Sabellariidae) from the shallow waters of Malaysia, with a note on the ecological traits of reefs

A new species of the genus Sabellaria Lamarck, 1818 (Annelida: Polychaeta: Sabellariidae) is described from the intertidal zone of Jeram, Selangor, Malaysia. Sabellaria jeramae n. sp. is a gregarious species that constructs large reefs several hundreds of meters long and 50-200 m wide. The new species is distinguished from other congeners by the character combination of the presence of a single kind of middle paleae with conspicuous morphology, and outer paleae with long frayed teeth. Morphological features of the species are described and compared to those of all congeneric species. We also compare the reef structure and geographical distribution of the new species to those of the members of the family Sabellariidae around the world, demonstrating the ecological traits of the reefs.

Competition for shelter in a high-diversity system: structure use by large reef fishes

Competition among large reef fishes for shelter beneath tabular structures provides a rare opportunity to study competition in a species-rich environment. The system permits a detailed study of localised competition with major implications for coral reefs with respect to human impacts including climate change. Using underwater video cameras, this study examined competition among 30 species of large reef fishes (from nine families) for access to shelter provided by 26 tabular structures, which may be the highest reported diversity of vertebrates competing for a single resource. Mean concentrations of fishes under tabular structures were also among the highest biomass recorded on reefs (4.71 kg m−2). A generated dominance hierarchy for the occupation of shelter appeared to be primarily driven by the size of fishes. In contrast to previous studies, fishes higher in the hierarchy tended to exhibit the lowest levels of aggression. However, size difference between fishes was found to be strongly negatively correlated with the proportion of aggressive interactions (R2 = 0.971, P < 0.0001). The strong competition for the shade provided by these corals highlights concerns about future shifts in the structure of large reef fish communities as corals are lost. This is particularly concerning given the critical functional roles played by certain species of large reef fishes that utilise tabular structure for shelter and which occupy the lower ranks of the dominance hierarchy.

Individuals in Kulkalgal history

This paper explores the lives of three individuals and their impact on the history of the Torres Strait and on world events. While this is an international history, it is centred on travels near Warrior Reef, a large reef system in central Torres Strait used by Kulkalgal and others. The three individuals whose histories are given here come from three different places (Mowata village, Papua New Guinea; Tudu Island, Torres Strait; and Tongatapu Island, Tonga), but they are interconnected through the maritime road they travel and through the relationships that drive their actions across the seas. In written historical narratives, these men have a marginal impact on commerce, science, religion and international politics. This paper gives a central place to these men, and their agency in past events is made explicit. In concluding, we consider their actions as purposeful gifts for future generations.

New seismic attribute technology for predicting dissolved pore-fracture of deeply buried platform margin reef-beach system in Northeast Sichuan Basin, China

The large reef complexes of the Upper Permian Changxing Formation, with a significant breakthrough for petroleum exploration, are an important target for petroleum exploration in the Yuanba area of the Sichuan Basin in SW China. The storage space types of reef complexes are dominated by the dissolved pore-fracture (DPF). However, using only single geophysical methods, it is difficult to predict effective distribution of DPF. Based on a combination of geological models and geophysics technology, this study proposes two new geophysical methods, including anisotropy coherence technique (ACT) and fracture intensity inversion (FII), to research the characteristics of DPF by facies-controlling in Changxing Formation in Yuanba area. Two major findings are presented as follows: (1) the characteristics of DPF varying with facies are the result of different diagenetic and petrophysical property. The intensity of DPF decreases from reef and bioclastic bank to interbank sea and slope; (2) ACT can qualitatively identify the distribution of DPF with no-directional and dispersed distribution, while FII can quantitatively characterize the intensity of DPF development within various sedimentary facies. When integrated into the geological study, ACT and FII can provide an effective way to predict the distribution of DPF in similar geological settings and the predicted DPF have been supported by the historical well data.

Aggradation and carbonate accumulation of Holocene Norwegian cold‐water coral reefs

AbstractCold‐water coral ecosystems present common carbonate factories along the Atlantic continental margins, where they can form large reef structures. There is increasing knowledge on their ecology, molecular genetics, environmental controls and threats available. However, information on their carbo‐nate production and accumulation is still very limited, even though this information is essential for their evaluation as carbonate sinks. The aim of this study is to provide high‐resolution reef aggradation and carbonate accumulation rates for Norwegian cold‐water coral reefs from various settings (sunds, inner shelf and shelf margin). Furthermore, it introduces a new approach for the evaluation of the cold‐water coral preservation within cold‐water coral deposits by computed tomography analysis. This approach allows the differentiation of various kinds of cold‐water coral deposits by their macrofossil clast size and orientation signature. The obtained results suggest that preservation of cold‐water coral frameworks in living position is favoured by high reef aggradation rates, while preservation of coral rubble prevails by moderate aggradation rates. A high degree of macrofossil fragmentation indicates condensed intervals or unconformities. The observed aggradation rates with up to 1500 cm kyr−1 exhibit the highest rates from cold‐water coral reefs so far. Reef aggradation within the studied cores was restricted to the Early and Late Holocene. Available datings of Norwegian cold‐water corals support this age pattern for other fjords while, on the shelf, cold‐water coral ages are reported additionally from the early Middle Holocene. The obtained mean carbonate accumulation rates of up to 103 g cm−2 kyr−1 exceed previous estimates of cold‐water coral reefs by a factor of two to three and by almost one order of magnitude to adjacent sedimentary environments (shelf, slope and deep sea). Only fjord basins locally exhibit carbonate accumulation rates in the range of the cold‐water coral reefs. Furthermore, cold‐water coral reef carbonate accumulation rates are in the range of tropical reef carbonate accumulation rates. These results clearly suggest the importance of cold‐water coral reefs as local, maybe regional to global, carbonate sinks.

Total volume of 3D small patch reefs reflected in aerial photographs can predict total species richness of coral reef damselfish assemblages on a shallow back reef

AbstractBecause fish have a high dispersal ability, an understanding coral reef fish metacommunity structure is vital for effective conservation. Coral reefs provide patchy habitat of various sizes and scales. We examined the species–area relationship (SAR) of damselfish (Pomacentridae) assemblages over 81 environmentally homogenous patch reefs ranging 0.07–45.4 m2 with low coral cover. Patch reefs were located in the shallow back reef (&lt;2.5 m deep) off Ishigaki Island, Japan. Reef area was measured by performing image analysis of enlarged sections of a high‐resolution (&gt;1/2500) color aerial photograph used as a fine‐scale seascape map. To assess the effects of three‐dimensional meso‐scale rugosity on species richness, we assumed that all reefs had a cylindrical shape and examined species by volume (area × height) relationships (SVR). Patch reef volume was a better determinant of species richness than area, and the regression functions of SVR provided better estimates of patch reef species richness. Neither the observed SVRs nor SARs, however, could be explained by a random placement model alone. Our results suggest that several small reefs are likely to have higher species richness than a single large reef of equivalent area in the shallow back reef where large patch reefs are flat. Thus, total patch reef volume (area × height) better reflects meso‐scale rugosity and is a useful indicator of total species richness relative to the total amount of essential habitat in shallow back reefs.

Human, oceanographic and habitat drivers of central and western Pacific coral reef fish assemblages.

Coral reefs around US- and US-affiliated Pacific islands and atolls span wide oceanographic gradients and levels of human impact. Here we examine the relative influence of these factors on coral reef fish biomass, using data from a consistent large-scale ecosystem monitoring program conducted by scientific divers over the course of >2,000 hours of underwater observation at 1,934 sites, across ~40 islands and atolls. Consistent with previous smaller-scale studies, our results show sharp declines in reef fish biomass at relatively low human population density, followed by more gradual declines as human population density increased further. Adjusting for other factors, the highest levels of oceanic productivity among our study locations were associated with more than double the biomass of reef fishes (including ~4 times the biomass of planktivores and piscivores) compared to islands with lowest oceanic productivity. Our results emphasize that coral reef areas do not all have equal ability to sustain large reef fish stocks, and that what is natural varies significantly amongst locations. Comparisons of biomass estimates derived from visual surveys with predicted biomass in the absence of humans indicated that total reef fish biomass was depleted by 61% to 69% at populated islands in the Mariana Archipelago; by 20% to 78% in the Main Hawaiian islands; and by 21% to 56% in American Samoa.

Fishers' knowledge about fish trophic interactions in the southeastern Brazilian coast.

BackgroundData derived from studies of fishers’ local ecological knowledge (LEK) can be invaluable to the proposal of new studies and more appropriate management strategies. This study analyzed the fisher’s LEK about trophic relationships of fishes in the southeastern Brazilian coast, comparing fishers’ LEK with scientific knowledge to provide new hypotheses.MethodsThe initial contacts with fishers were made through informal visits in their residences, to explain the research goals, meet fishers and their families, check the number of resident fishers and ask for fishers’ consent to participate in the research. After this initial contact, fishers were selected to be included in the interviews through the technique of snowball sampling. The fishers indicated by others who attended the criteria to be included in the research were interviewed by using a semi-structured standard questionnaire.ResultsThere were interviewed 26 artisanal fishers from three communities of the Ilhabela: Jabaquara, Fome and Serraria. The interviewed fishers showed a detailed knowledge about the trophic interactions of the studied coastal fishes, as fishers mentioned 17 food items for these fishes and six fish and three mammals as fish predators. The most mentioned food items were small fish, shrimps and crabs, while the most mentioned predators were large reef fishes. Fishers also mentioned some predators, such as sea otters, that have not been reported by the biological literature and are poorly known.ConclusionsThe LEK of the studied fishers showed a high degree of concordance with the scientific literature regarding fish diet. This study evidenced the value of fishers’ LEK to improve fisheries research and management, as well as the needy to increase the collaboration among managers, biologists and fishers.

Emergence and epidemiology of ciguatera in the coastal cities of southern China.

In the present review of 23 published case studies, the main objective is to report the emergence and epidemiology of ciguatera in the coastal cities of southern China. There was a sudden surge in ciguatera outbreaks in 2004. Ciguatera mostly occurred in the Guangdong Province. In Shenzhen, the incidence of ciguatera in 2004 was estimated to be over 7.5 per million people. In Foshan and Zhongshan, three large outbreaks each affecting over 100–200 subjects (caused by tiger grouper served at banquets) accounted for the much higher incidence of ciguatera in 2004 (>48.7 and >129.9 per million people). Humphead wrasse and areolated coral grouper were the other important ciguatoxic fish. In some subjects, risk factors for increased likelihood of (severe) ciguatera were present, namely concomitant alcohol consumption and ingestion of large reef fishes and CTX-rich fish parts. To prevent large outbreaks and severe illness, large apex predators from coral reefs should never be served at banquets and the public should realize the increased risk of severe symptoms due to ingestion of CTX-rich fish parts with alcohol. The systematic collection of accurate details, implementation of risk assessment process and continuing education for the public on prevention are of obvious importance.

The functional role of tabular structures for large reef fishes: avoiding predators or solar irradiance?

Large reef fishes may often be seen sheltering under tabular structures on coral reefs. There are two principle explanations for this behaviour: avoidance of predation or avoidance of solar irradiance. This study sought supporting evidence to distinguish between these two explanations by examining the usage of tabular structures on a shallow mid-shelf reef of the Great Barrier Reef at midday and sunset. If predation avoidance is most important, usage should increase towards sunset; conversely, if avoidance of solar radiation is most important, more fishes should use cover at midday. Underwater video observations revealed that tabular structures were extensively used by large reef fishes at midday, being characterised by numerous species, especially Lutjanidae and Haemulidae. In contrast, at sunset, tabular structures were used by significantly fewer large reef fishes, being characterised mostly by species of unicornfish (Naso spp.). Resident times of fishes using tabular structures were also significantly longer at midday (28:06 ± 5:55 min) than at sunset (07:47 ± 2:19 min). The results suggest that the primary function of tabular structures for large reef fishes is the avoidance of solar irradiance. This suggestion is supported by the position of fishes when sheltering. The majority of large reef fishes were found to shelter under the lip of tabular structure, facing outwards. This behaviour is thought to allow protection from harmful downwelling UV-B irradiance while allowing the fish to retain photopic vision and survey more of the surrounding area. These findings help to explain the importance of tabular structures for large reef fishes on coral reefs, potentially providing a valuable energetic refuge from solar irradiance.

Depth and Artificial Reef Type Effects on Size and Distribution of Red Snapper in the Northern Gulf of Mexico

AbstractThe Red Snapper Lutjanus campechanus is a highly exploited commercial and recreational species that dominates the artificial reef systems in the northern Gulf of Mexico. Off coastal Alabama there are few natural reefs, but in the last 50 years government programs and private fishers have placed numerous artificial reefs in the northeast Gulf of Mexico with the goal of increasing fisheries production. We examined the effects of artificial reef depth and reef type on Red Snapper densities and size distributions. We used hook‐and‐line, fish trap, and scuba visual surveys to estimate Red Snapper densities on four types of artificial reefs: army tanks, pyramids, small reefs (e.g., metal cages, pipelines), and large reefs (e.g., ships, dry docks, oil platforms). Small Red Snapper (&lt;33 cm TL) were significantly more abundant at shallower depths (&lt;35 m) and on small artificial reefs. Army tanks showed significantly more large fish (&gt;33 cm TL) at shallow sites (&lt;35 m) than at deeper sites (&gt;35 m); in contrast, pyramids showed significantly more large fish at deeper sites. Ontogenetic habitat shift and fishing mortality were the most likely factors that would explain these Red Snapper distributions. Worldwide, artificial reefs are being used to enhance fishery resources and for habitat restoration. We document the importance of reef design and deployment location for Red Snapper, as well as the need for future artificial reef deployments to consider the relevant variables that affect the species that managers are attempting to enhance.Received May 4, 2014; accepted October 20, 2014

Seeing through the dolerite-seismic imaging of petroleum systems, Tasmania, Australia

Prior to the onshore work of Empire Energy Corporation International (Empire) it was widely believed that the widespread sheets (&gt;650 m thick) of Jurassic dolerite (diabase) would not only have destroyed the many potential petroleum source and reservoir rocks in the basin but would also absorb seismic energy and would be impossible to drill. By using innovative acquisition parameters, however, major and minor structures and formations can be identified on the 1,149 km of 2D Vibroseis. Four Vibroseis trucks were used with a frequency range of 6–140 Hz with full frequency sweeps close together, thereby achieving maximum input and return signal. Potential reservoir and source rocks may be seismically mapped within the Gondwanan Petroleum System (GPS) of the Carboniferous to Triassic Parmeener Supergroup in the Tasmania Basin. Evidence for a working GPS is from a seep of migrated, Tasmanite-sourced, heavy crude oil in fractured dolerite and an oil-bearing breached reservoir in Permian siliciclastics. Empire’s wells show that each dolerite sheet consists of several intrusive units and that contact metamorphism is usually restricted to within 70 m of the sheets’ lower margins. In places, there are two thick sheets, as on Bruny Island. One near-continuous 6,500 km2 sheet is mapped seismically across central Tasmania and is expected, along with widespread Permian mudstones, to have acted as an excellent regional seal. The highly irregular pre-Parmeener unconformity can be mapped across Tasmania and large anticlines (Bellevue and Thunderbolt prospects and Derwent Bridge Anticline) and probable reefs can be seismically mapped beneath this unconformity within the Ordovician Larapintine Petroleum System. Two independent calculations of mean undiscovered potential (or prospective) resources in structures defined so far by Empire’s seismic surveys are 596.9 MMBOE (millions of barrels of oil equivalent) and 668.8 MMBOE.

Habitat use and abundance of goliath grouper Epinephelus itajara in Brazil: a participative survey

Developing survey strategies for threatened species is often limited by access to sufficient individuals to acquire information needed to design appropriate conservation measures. The goliath grouper (Epinephelus itajara) is a large reef fish, globally classified as critically endangered. In Brazil, fishing has been prohibited since 2002. Herein we investigated habitat use and abundance of E. itajara in Brazil drawn from a participative survey, which engaged volunteer divers in data-collection. A total of 188 reports were recorded between 2005 to 2011 throughout 13 Brazilian states. Our results revealed that habitat type influenced the relationship between total length and depth of occurrence of E. itajara. We observed a significant difference between habitats, artificial presented a nonlinear and natural an asymptotic relationship. This study underscores the importance of developing conservation measures addressing specific habitats and locations to enhance population recovery. Artificial structures (shipwrecks and manmade reefs) are critical habitats that must be considered as highly sensitive areas to E. itajara strategic conservation policies. We suggest the creation and implementation of marine protected areas, as key strategies for E. itajaraconservation, especially for artificial habitats and aggregation sites.

The development of the Betton Farm Coral Bed within the Malton Oolite Member (Upper Jurassic, Middle Oxfordian) of the Scarborough District, North Yorkshire, UK

Summary Betton Farm quarries contain, within a small area, a remarkable range of facies associated with the development of a Jurassic coral reef. A NW–SE-trending barrier reef protected the whole area containing the two quarries. Betton Farm North Quarry displays Thamnasteria patch reefs. These consist of scattered, 1 m high masses of colonial coral surrounded by reef debris that were situated behind the barrier within a large reef platform area. In Betton Farm South Quarry, bioclastic sand, consisting largely of coral and bivalve debris, interdigitates with the development of a small ribbon reef made up of the massive colonial coral Thamnasteria . This ribbon reef, only 3 to 4 m wide, sheltered a lagoonal area that accumulated lime mud and was colonized by large gastropods and burrowing bivalves. A fauna of reef-specializing bivalves and echinoids occupied these areas of patch/ribbon reef development, which were periodically swept by nutrient-bearing currents. Competition between the growth of the ribbon of Thamnasteria and the accumulation of fringing sediments saw periods when the Thamnasteria expanded over the coral-shell sand, and periods when the encroaching sediment cut back the growth of the Thamnasteria considerably. Considered initially to represent the Coral Rag Member of the Coralline Oolite Formation, the Betton Farm Coral Bed is now seen to represent localized coral reef developments situated near the base of the Malton Oolite Member, and growing upon antecedent bedrock features such as hard-ground surfaces that formed during pauses in sedimentation of the Malton Oolite.

Do tabular corals constitute keystone structures for fishes on coral reefs?

This study examined the changes in community composition of reef fishes by experimentally manipulating the availability of shelter provided by tabular structures on a mid-shelf reef on the Great Barrier Reef. At locations where access to tabular corals (Acropora hyacinthus and Acropora cytherea) was excluded, a rapid and sustained reduction in the abundance of large reef fishes occurred. At locations where tabular structure was added, the abundance and diversity of large reef fishes increased and the abundance of small reef fishes tended to decrease, although over a longer time frame. Based on their response to changes in the availability of tabular structures, nine families of large reef fishes were separated into three categories; designated as obligate, facultative or non-structure users. This relationship may relate to the particular ecological demands of each family, including avoidance of predation and ultraviolet radiation, access to feeding areas and reef navigation. This study highlights the importance of tabular corals for large reef fishes in shallow reef environments and provides a possible mechanism for local changes in the abundance of reef fishes following loss of structural complexity on coral reefs. Keystone structures have a distinct structure and disproportionate effect on their ecosystem relative to their abundance, as such the result of this study suggests tabular corals may constitute keystone structures on shallow coral reefs.

Revisiting Squires' Coral Coppice, Campbell Plateau, New Zealand

A ridge-like structure on the Campbell Plateau southeast of New Zealand, previously identified by Squires as a coral coppice, has been relocated (50° 41.46′S, 167° 41.45′E) and its extent and morphology mapped using multibeam and backscatter data obtained during an opportunistic survey. There are at least three other similar features at this location on a seafloor bank, although only two were fully mapped. ‘Squires’ Coral Coppice' is extensive, measuring 6700 m long, 900 m wide and up to 50 m high relative to the surrounding seafloor, in water depths of 273–325 m. Bathymetric profiles, backscatter data and historical samples of deep-sea coral (mainly Goniocorella dumosa) were used to infer that the ridge-like structures are coral reefs. The presence of deep-water coral reefs in the area could be due to the unique combination of geological (hard substrata), biological (high productivity) and oceanographic (relatively strong eastward flowing currents, seasonal vertical mixing) conditions east of Auckland Island. Squires' Coral Coppice covers an area of 9.2 km2 which makes it similar in size to some of the deep-water reefs and mounds in the North Atlantic, and it could represent the only known large coral reef (> 1 km maximum continuous extent) in the Southern Hemisphere. Further surveys are required to visually confirm that the relocated features are coral reefs, and to determine if similar features/coral reefs occur elsewhere on the Campbell Plateau. Deep-water coral reefs can support high levels of biodiversity and are vulnerable marine ecosystems that should be considered for protection in the region.

Vortical ciliary flows actively enhance mass transport in reef corals.

The exchange of nutrients and dissolved gasses between corals and their environment is a critical determinant of the growth of coral colonies and the productivity of coral reefs. To date, this exchange has been assumed to be limited by molecular diffusion through an unstirred boundary layer extending 1-2 mm from the coral surface, with corals relying solely on external flow to overcome this limitation. Here, we present direct microscopic evidence that, instead, corals can actively enhance mass transport through strong vortical flows driven by motile epidermal cilia covering their entire surface. Ciliary beating produces quasi-steady arrays of counterrotating vortices that vigorously stir a layer of water extending up to 2 mm from the coral surface. We show that, under low ambient flow velocities, these vortices, rather than molecular diffusion, control the exchange of nutrients and oxygen between the coral and its environment, enhancing mass transfer rates by up to 400%. This ability of corals to stir their boundary layer changes the way that we perceive the microenvironment of coral surfaces, revealing an active mechanism complementing the passive enhancement of transport by ambient flow. These findings extend our understanding of mass transport processes in reef corals and may shed new light on the evolutionary success of corals and coral reefs.

Fishing down the largest coral reef fish species

Studies on remote, uninhabited, near-pristine reefs have revealed surprisingly large populations of large reef fish. Locations such as the northwestern Hawaiian Islands, northern Marianas Islands, Line Islands, U.S. remote Pacific Islands, Cocos-Keeling Atoll and Chagos archipelago have much higher reef fish biomass than islands and reefs near people. Much of the high biomass of most remote reef fish communities lies in the largest species, such as sharks, bumphead parrots, giant trevally, and humphead wrasse. Some, such as sharks and giant trevally, are apex predators, but others such as bumphead parrots and humphead wrasse, are not. At many locations, decreases in large reef fish species have been attributed to fishing. Fishing is well known to remove the largest fish first, and a quantitative measure of vulnerability to fishing indicates that large reef fish species are much more vulnerable to fishing than small fish. The removal of large reef fish by fishing parallels the extinction of terrestrial megafauna by early humans. However large reef fish have great value for various ecological roles and for reef tourism.

Distribution and activity of virioplankton in the Toliara Large Reef (Madagascar)

Until then, the study of aquatic viruses concerned almost exclusively temperate and polar environments while the tropics were rarely explored. In this study, we examined the spatial and temporal variability of viral and bacterial communities in two different tide periods (spring/ neap tide), on 22 stations covering the Toliara Large Reef (TLR) located in Madagascar. The coupling of these two communities was also analyzed in several contrasted stations of the reef by physiological and ecological descriptors means. The epifluorescence microscopy technique allowed to achieve the bacterial and viral count support of this work. The results obtained show that the bacterial and viral concentrations for the whole TLR were significantly higher during spring than neap tide, probably because of the hydrodynamics very marked in this area. In addition, the Mitomycin C used permitted to establish that the cells fraction in phase of lysogenic infection was very low (&lt; 3%) despite the oligotrophic status of TLR waters. This suggests that the lysogeny was the viral reproduction dominant strategy, which was diverted spontaneously and in a continuous way towards the lytic pathway, under the solar conditions’ influence. Finally, we show that the viruses form a dynamic and ubiquitous component of reef ecosystems, whose activity appears once again, closely related to the physico-chemical and biological environment nature.Keywords: Virus, lysogeny, lysis, tropical latitude

Permanent aggregations of a pelagic predator at shallow seamounts

The effectiveness of marine reserves for highly mobile reef fishes such as jacks and trevallies is normally assumed to be small, even though we generally lack the understanding of their long-term movement patterns. In this work, we combined the analysis of multi-year landings and underwater visual census with acoustic telemetry to investigate the long-term movement patterns (up to 4 years) of almaco jack, Seriola rivoliana, a large reef top predator, in one protected and one unprotected offshore shallow seamount in the Azores, central North Atlantic. Although the analysis of visual census and landing data suggests a pronounced seasonal pattern of occurrence, we found that tagged fish were almost continuously detected at the seamounts for up to four consecutive years. Some individuals showed a few long periods of undetection of 1–2 months in the Formigas reserve, mostly in the fall and winter. Mobility within this seamount increased during spring and summer, and geostrophic current speed was negatively correlated with detection probability. Overall, the acoustic telemetry results showed that adult almaco jacks were resident year-round, refuting the traditional view that these fish are essentially migratory and a seasonal occurrence in the Azores. Given the intrinsic vulnerability of resident fish to fishing, our results highlight the importance of protecting these sites in order to preserve these mature fish aggregations with high reproductive potential.