Continuous Reef Research Articles

Quaternary subsidence history of Xisha Islands (northern South China Sea): Evidences from the reef-bank system

Subsidence is a potentially important factor influencing the evolution of carbonate platforms. Yet, few studies have been carried out on the quantitative reconstruction of subsidence history of carbonate platforms in the South China Sea. Using paleo-water depth constraints from core XK-1, drilled in the Xisha Islands, northern South China Sea, the tectonic and total subsidence history of Xisha Islands during the Quaternary is quantitatively reconstructed in this study. Slow tectonic subsidence between 1.945 and 0.988 Ma was related with magmatic intrusion beneath the Xisha Islands, while the relatively high tectonic subsidence rate between 0.988 and 0.781 Ma and the subsequent gradual decline in tectonic subsidence rate between 0.781 and 0.07 Ma were linked to the thermal cooling process. A rapid tectonic uplifting process after 0.07 Ma occurred as a result of compression and volcano eruption. Total subsidence rate showed an increase from the stage of 1.945–0.988 Ma to the stage of 0.988–0.781 Ma, and a gradual decline during the stage of 0.781–0.07 Ma. After 0.07 Ma, there was a rapid uplifting in response to the tectonic movement. The high eustatic sea level and intermediate total subsidence rate from 1.945 to 1.0 Ma caused the domination of bank deposits on the Xisha carbonate platform. From 0.988 to 0.65 Ma, the long-term eustatic sea-level lowering and the relatively high total subsidence rate favored the production of thick reef units. By contrast, the low eustatic sea level and the slow total subsidence between 0.65 and 0.42 Ma forced the accommodation space to be limited, resulting in formation of thin reef-bank deposits and occurrence of exposure horizons. During the stage of slow subsidence, the high eustatic sea level around 0.4 Ma allowed the last presence of thick reef unit in the Quaternary section, after which the lower eustatic sea level reduced the accommodation space again and only thin bioclastic bank deposits and iron-stained exposure horizon occurred. Around 0.07 Ma, the Xisha Islands were continuously exposed due to the uplifting and low eustatic sea level. The strong winter monsoon caused a heterozoan factory nearby the Xisha Islands, and blew the carbonate sediments onshore forming aeolianites. Our results proves that the total subsidence has indeed greatly influenced the evolution of Quaternary carbonate system in the Xisha area. The long-term (at scale of Myr) sea-level lowering could facilitate the flourishment of corals, and a moderate total subsidence in the context of secular sea-level lowering would provide more effective accommodation space for the continuous reef accretion, favoring the formation of thick reef units in the tropical areas.

Variable and spatially explicit response of fish larvae to the playback of local, continuous reef soundscapes

Understanding the cues that drive larval fish settlement is critical for managing reef systems under stress. Reef sound is increasingly reported to influence fish recruitment, yet the physical and acoustic environment in which larval fish settle varies in space and time. Accordingly, testing potential settlement cues under different conditions is vital for understanding their ecological importance. We conducted 2 sets of field playback experiments in St. John, US Virgin Islands, one nearshore (10 m depth) and the second ‘offshore’ (25 m depth), to assess the effects of reef soundscape playback on settlement rates of multiple reef fish families. In each experiment, nightly currents were quantified and we replicated the diel soundscape cycle using high, low, and control (silent) amplitude recordings from nearby reefs. The first experiment revealed significant current-based, down-stream reduction in larval fish catches in subsurface light traps and a significant effect of increasing amplitude of reef playbacks on larval lizardfish (Synodontidae) catches. In the second, offshore experiment which had no current effect, increasing reef playback amplitude led to a significantly greater catch of parrotfish (Scaridae) larvae and decreased larval pelagic fish catch. Total reef fish larvae only showed attraction to reef playbacks at the most nearshore site. This work demonstrates that while sound can play a role in the settlement of certain reef fishes, responses are influenced by multiple factors, including larger-scale physical processes, underscoring the need to consider the scale of soundscape cues for reef fish settlement within an oceanographic context.

Reef response to sea-level and environmental changes in the Central South Pacific over the past 6000 years

Geological records of coastal system evolution during past higher and/or rising sea levels provide an important baseline for developing projections regarding the response of modern coastal systems to future sea-level rise. The mid-late Holocene corresponds to the most recent window into natural variability prior to the Anthropocene and involves slow-rate and low-amplitude sea-level changes that were mostly governed by a limited glacio-eustatic contribution, most likely sourced from Antarctica, and ‘glacial isostatic adjustment’ processes. This paper documents in unprecedented detail the response of coral reefs and coastal systems to changing accommodation space in relation to mid-late Holocene sea-level changes in French Polynesia. The sea-level curve that underpins this study has a global significance and documents a single short-lived sea-level highstand between 4.10 and 3.40 kyr BP. The amplitude of the highstand is less than one metre, within the range of the predicted sea level at the end of the current century. The reported relative sea-level changes are characterized by slow rates ranging from a few tens of millimetres per year to up to 2.5 mm/yr and by significant sea-level stability (stillstands) lasting more than a century and up to 250 years, defining a step-like pattern. Sea-level variability probably driven by climatic oscillations on interannual to millennial time scales is evidenced during the entire time window. The detailed reconstruction of reef development over the last 6000 years brings valuable information regarding coral reef dynamics and coastal processes during periods of higher sea level and wave energy regimes. The persistence of stable and optimal depositional environments over the last 6000 years is demonstrated by the constant overall composition and diversity of reef communities and the almost continuous development of coral microatolls. The facies distribution as well as the lateral extension and shift of facies belts have been governed by variations in accommodation space, which are controlled by relative sea-level changes and antecedent topography. The widespread development of mid-late Holocene reef deposits in coastal areas suggests that they have played a prominent role in global processes related to the formation and shaping of modern islands. • Coral reef responses to slow-rate, low-amplitude, high-frequency sea-level changes. • Continuous reef development over the last 6000 years in optimal conditions. • Mid-late Holocene coral assemblages similar to their modern counterparts. • Facies distribution governed by variations in accommodation space. • Prominent role played by reef deposits in the formation and shaping of modern islands.

A novel sigma coordinate system to simulate abrupt changes of underwater terrain in a hydrodynamic model: application to Lake Mead, USA.

The sigma (SIG) coordinate system in ocean circulation simulation models results inevitably in horizontal pressure gradient error. This problem also emerges in models of deep lakes or reservoirs with the same characteristics of underwater terrain mutation. SIG coordinates reflect vertical relative stratification but cannot be used to calculate horizontal pressure gradient force in places with drastic topographic changes; this results in vertical water temperature and circulation errors. In deep lakes or reservoirs, differences in water density caused by the temperature difference between upper and lower water bodies is the primary cause of thermal stratification phenomena. Lake Mead was used as a case study on steep topography based on Environmental Fluid Dynamics Code (EFDC) model in this study. SIG coordinates result in close agreement between the calibrated temperature time series at the top and middle water layers, but disparity in the bottom water layer. The error emerges in the horizontal pressure gradient error due to the SIG coordinate transformation. Neither increasing the vertical resolution nor adjusting the horizontal viscosity coefficient resolve this error. We test the sigma-zed (SGZ) coordinate which combines Z coordinate and SIG coordinate as a replacement for the SIG coordinate to find that they effectively reduce the model's runtime and simulation efficiency. The vertical temperature distribution in SGZ coordinate mode is more accurate than the distribution in SIG coordinate mode. The Navier-Stokes horizontal gradient and advection diffusion equation results under SIG coordinates are very sensitive to the pressure gradient. The replacement also enhances resolution near the thermocline, facilitates reclosing of the water bottom and the equal sigma surface, lends significant advantages in terms of vertical temperature in the simulation for local deep water with steep terrain, and shortens runtime for 0.14h. SGZ mixed coordinates are recommended in the simulation of deep lakes or reservoirs wherein the underwater topography is large (with abundant continuous deep trenches or reefs).

A preliminary study on spatial assessment using conservation metrics for intertidal oyster reefs at the Hab River mouth in Pakistan

The oyster reefs in Pakistan are on the verge of extinction as a consequence of environmental and anthropogenic factors. A qualitative survey of oyster reef habitat was conducted from March-2017 to February-2018 in the Hab River Delta along the Balochistan coast (Arabian Sea), Pakistan. A combination of field survey and Geographical Information System (GIS) based approach (reef categorization, universal metrics and habitat suitability analysis), universal environmental variables, restoration goal-based metrics, sounding, condition indices, grain size composition and oyster spat-fall were determined for planning future oyster reef restoration efforts. The reefs were categorized into three main groups as dispersed, patch and continuous on the basis of fragmented spatial geometry. Dispersed reefs were more numerous than continuous and patch categories. The differences between morphometric measurements and density of oysters amongst reefs types were statistically insignificant. Habitat suitability analysis was done by ‘Benthic Terrain Modeler’ using ArcGIS software. The moderate, positive values of Bathymetric Position Index (BPI) of the oyster reef indicate an area of high or open slope with sea bottom (-2 to 6). The area of reef location shows high to moderate values of rugosity (0.7 to 0.9), indicates good to intermediate conditions; whereas, the aspect analysis showed slope orientation in the Northeast direction but mostly flat area. The environmental and restoration goal-based metrics were favorable for oyster growth and survival. The dispersed reefs showed lowest bathymetry points compared to patch and continuous reefs. The values of condition indices reveal not significant difference among reef types (continuous, dispersed and patch). Fine sand has the highest percentage (71%) followed by silt/clay fraction (18%). The higher density and spat size were recorded in monsoon (June to September) season. The current study suggests that the present reefs are viable and have potential for successful restoration and may be converted into a sizeable ecologic sanctuary.

Ecotourism affects breeding in sergeant major damselfish (Abudefduf saxatilis)

We studied the effect of tourist activity on the reproductive success of sergeant major damselfish (Abudefduf saxatilis). We snorkeled at two sites – one with a bridge over the reef allowing access to the reef from the seaside (Princess beach) and further south where the number of tourists is low (Taba beach). We identified 36 (65.5%) nests on the Princess reef and 19 (34.5%) on the Taba reefs. Average nest size at Princess was 11.8 cm2 (±2.68 SD) vs 19.6 cm2 (±3.9) at Taba. Further, at Princess although the number of nests was not correlated to the distance from the bridge (R2 = 0.352), average nest size increased with distance from the bridge (R2 = 0.861). At Taba, nests on the continuous reef averaged 21.8 cm2 (±1.8, N = 13) while those on the loose aggregation reefs averaged 14.8 cm2 (±2.02, N = 6). Although reef tourism is increasingly being regarded a major source to generate income for human coastal communities, a better understanding of the consequences of human activities to the reef system can enhance conservation initiatives and facilitate management implementation.

Assessing mesophotic coral ecosystems inside and outside a Caribbean marine protected area.

Widespread shallow coral reef loss has led to calls for more holistic approaches to coral reef management, requiring inclusion of ecosystems interacting with shallow coral reefs in management plans. Yet, almost all current reef management is biased towards shallow reefs, and overlooks that coral reefs extend beyond shallow waters to mesophotic coral ecosystems (MCEs; 30–150 m). We present the first detailed quantitative characterization of MCEs off Cozumel, Mexico, on the northern Mesoamerican Reef in the Mexican Caribbean, and provide insights into their general state. We documented MCE biodiversity, and assessed whether MCEs adjacent to a major town and port, where coastal development has caused shallow reef damage, have similar benthic and fish communities to MCEs within a National Park. Our results show that overall MCE communities are similar regardless of protection, though some taxa-specific differences exist in benthic communities between sites within the MPA and areas outside. Regardless of protection and location, and in contrast to shallow reefs, all observed Cozumel MCEs were continuous reefs with the main structural habitat complexity provided by calcareous macroalgae, sponges, gorgonians and black corals. Hard corals were present on MCEs, although at low abundance. We found that 42.5% of fish species recorded on Cozumel could be found on both shallow reefs and MCEs, including 39.6% of commercially valuable fish species. These results suggest that MCEs could play an important role in supporting fish populations. However, regardless of protection and depth, we found few large-body fishes (greater than 500 mm), which were nearly absent at all studied sites. Cozumel MCEs contain diverse benthic and fish assemblages, including commercially valuable fisheries species and ecosystem engineers, such as black corals. Because of their inherent biodiversity and identified threats, MCEs should be incorporated into shallow-reef-focused Cozumel National Park management plan.

Origin of Reef-Style PGE Mineralization in the Paleoproterozoic Monchegorsk Complex, Kola Region, Russia

The Paleoproterozoic Monchegorsk Complex in northwest Russia represents one of the largest layered intrusions in Europe and hosts several examples of broadly stratiform platinum group element (PGE) mineralization at different stratigraphic levels of the intrusion that have been suggested to represent reef-style mineralization. The Sopcha reef occurs in the ultramafic lower portion of the complex and constitutes an up to 6-m-thick succession of layered, mineralized dunite, harzburgite, and olivine-orthopyroxenite, with peak grades of 3.4 ppm Pt + Pd and 1.1 wt % Ni. Another PGE occurrence is hosted by the leucogabbronoritic to anorthositic Vuruchuaivench intrusion, which represents part of the mafic upper portion of the Monchegorsk Complex. The disseminated sulfide mineralization reaches up to 7.3 ppm Pt + Pd and is concentrated in several lenticular bodies over a strike length of ~5 km, rather than in a laterally continuous reef as previously suggested. Moreover, our work identified a previously unreported minor enrichment in precious metals of up to 0.2 ppm Pt + Pd in leucogabbroic rocks of the Monchetundra intrusion, which represents the uppermost portion of the Monchegorsk Complex and belongs to the more than 60-km-long mafic Main Ridge. Detailed lithophile and chalcophile element data, coupled with mineral chemistry, indicate that the PGE mineralization at Sopcha and Vuruchuaivench does not represent classic reef-style mineralization, which is commonly narrow and marked by a sharp increase in Cu/Pd ratios, reflecting the in situ sulfide saturation within a large magma chamber. Instead, it is more likely that the Sopcha reef was emplaced as a crustally contaminated and sulfide-saturated, olivine-rich crystal mush that was sourced from a deeper chamber. The Sopcha mineralization is characterized by Pd/Pt > 5 and Pd/Ir > 55, similar to contact-style mineralization elsewhere in the complex, possibly suggesting a common origin of the sulfides. The mineralized Vuruchuaivench rocks have similar Pd/Pt but much higher Pd/Ir ratios of up to 600, whereas the unmineralized host rocks, below as well as above the mineralization, have Pd/Ir ratios <100 and Pd/Pt ratios <2. These data indicate that the PGE-rich sulfides did not segregate in situ from the same magma that crystallized the host gabbronorites and anorthosites at Vuruchuaivench. Considering R factor and sulfide fractionation modeling results, we suggest that the mineralized Vuruchuaivench rocks represent a sill-like intrusion of gabbroic crystal mushes, which have entrained fractionated sulfide liquid that is related to an earlier sulfide saturation event. In contrast, the mineralized leucogabbroic rocks from the Monchetundra intrusion are characterized by a sharp increase in Cu/Pd ratios, which is consistent with a classic PGE reef model, in which sulfide saturation was triggered in situ by extensive fractionation and possibly affected the entire magma chamber. Furthermore, the Pd/Ir and Pd/Pt ratios of the mineralized horizon are distinctly lower at <66 and <1 in comparison to all other types of mineralization in the Monchegorsk Complex. The potential of this mineralization style elsewhere in the Main Ridge remains to be evaluated.

Genetic connectivity of a coral reef ecosystem predator: the population genetic structure and evolutionary history of the Caribbean reef shark (Carcharhinus perezi)

AbstractAimThe Caribbean reef shark (Carcharhinus perezi) is one of few extant reef sharks inhabiting the Atlantic Ocean. Its variability in movements across habitat types suggests the possibility of a complex genetic population structure. Here, we use mitochondrial and nuclearDNAto investigate the genetic connectivity of the Caribbean reef shark across contemporary and evolutionary time‐scales and relate our findings to the ecology of this understudied species.LocationTropical western Atlantic and Caribbean.MethodsSamples were obtained from 216 individuals from six western Atlantic and Caribbean locations. Individuals were genotyped at seven nuclear microsatelliteDNAloci and sequenced at two mitochondrial (control region [CR];NADHdehydrogenase subunit 4 [ND4]) and one nuclear locus (lactate dehydrogenase [LDH]). Analyses to resolve the population genetic structure and evolutionary history of this species were adopted.ResultsSequencing of theCR(1,068 bp,n = 216),ND4 (741 bp,n = 213) andLDH(258 bp,n = 165) loci, resolved 11, 8 and 13 unique haplotypes (or alleles), respectively. Overall, Caribbean reef sharks showed low levels of genetic diversity and most marker sets identified strong genetic differences (FSTand ΦST) between sharks sampled in Brazil versus all other locations (msatFST &gt; 0.017;CR‐ND4 ΦST &gt; 0.013). MitochondrialDNAshowed evidence of increased genetic partitioning among western North Atlantic sampling sites, although widespread haplotype sharing (~85%–92%) and a shallow population history were found.Main ConclusionsFindings of genetic differentiation are concordant with previous movement studies showing residency and/or site‐fidelity to specific locations by individuals. However, similar to other reef shark studies, we found that the level of genetic connectivity among populations was context dependent—i.e., sharks occupying isolated habitats showed greater genetic differentiation compared with those sharks occupying semi‐isolated or continuous reef habitats. Furthermore, low genetic diversity and a shallow mitochondrial population history were found, suggesting historical demographic fluctuations, including population collapse and more recent expansions.

Determining conservation potential of an opportunistically defined MPA boundary using fish telemetry

Marine protected areas (MPA) that are created opportunistically must be evaluated in an ecological context to ensure that conservation goals and societal expectations are achievable. This study used acoustic telemetry to investigate movements of reef fish relative to the boundary of the Virgin Islands Coral Reef National Monument (VICRNM) in Coral Bay, U.S. Virgin Islands. Although created to enhance ecosystem protection, VICRNM boundaries were established purely on the basis of adjacency to public versus privately owned lands. Transmitters were implanted into a diversity of reef fish species representative of the local community whose movements were logged for one year on an array of acoustic-receivers that were positioned within, outside, and along the MPA boundary. Results indicate that the boundary has coincidentally aligned with a deep sandy area that does not cross through continuous reef or mangrove habitat. This acted as a natural barrier to movements of species such as Lutjanus griseus, Epinephelus guttatus, Cephalopholus cruentatus, Holocentrus rufus, and Sparisoma aurofrenatum. Other species were more mobile and were routinely detected outside VICRNM, especially at night, such as L. synagris, Haemulon plumierii, and H. sciurus. In addition to fish movements in relation to the VICRNM boundary, network analysis revealed several hotspots of concentrated fish activity including a reef promontory and bay mouths. Investment in enforcement of existing regulations to protect fish is warranted to realize the full potential of this MPA. Using these types of data, management actions in this and other MPAs can be focused on those species and locations that would experience the greatest benefit.

Stratigraphy of the Middle Devonian Keg River and Prairie Evaporite formations, northeast Alberta, Canada

Stratigraphy of the Middle Devonian Keg River and Prairie Evaporite formations, northeast Alberta, Canada

Habitat specialisation, site fidelity and sociality predict homing success in coral reef cardinalfish

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 558:81-96 (2016) - DOI: https://doi.org/10.3354/meps11866 Habitat specialisation, site fidelity and sociality predict homing success in coral reef cardinalfish N. M. Gardiner1,*, G. P. Jones1,2 1Department of Marine Biology & Aquaculture, College of Science & Engineering, James Cook University, Townsville, QLD 4812, Australia 2ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 4812, Australia *Corresponding author: naomi.gardiner@jcu.edu.au ABSTRACT: Species that home demonstrate faithfulness to a particular location; however, not all species with high site fidelity can or will home. These movement decisions are often mediated by a species’ social behaviour and habitat preferences. Here we explored how habitat specialisation, site fidelity and social traits relate to homing behaviour in 5 species of cardinalfish (family Apogonidae). We also compared species’ capacity to home across open water versus continuous reefscapes. To track site fidelity and then homing behaviour, the precise locations of over 1200 tagged cardinalfish on Kimbe Bay reefs (West New Britain, Papua New Guinea) were visually monitored over time. Following experimental displacement, all species homed quickly across ~400 m of both open water and continuous reef habitats. Incredibly, individuals of one species homed up to 5 km across multiple reef and inter-reef passages. Homing was not coupled with site fidelity, as both low and high fidelity species homed well. However, it was correlated with the degree of habitat specialisation, with specialist species returning in greater numbers than generalist species. Social traits alone did not predict stronger homing behaviours, but gregarious species with high site fidelity homed better than the less social and less specialised species. Hence, both social factors and habitat preferences appear to influence the propensity to home. Generalist species and those that do not form rigid social groups are more likely to be able to settle for new sites and have less need to return to precise locations. KEY WORDS: Homing · Behaviour · Habitat specialisation · Aggregation · Coral reef fish · Social preferences · Apogonidae Full text in pdf format PreviousNextCite this article as: Gardiner NM, Jones GP (2016) Habitat specialisation, site fidelity and sociality predict homing success in coral reef cardinalfish. Mar Ecol Prog Ser 558:81-96. https://doi.org/10.3354/meps11866 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 558. Online publication date: October 25, 2016 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2016 Inter-Research.

Modern sediments and Pleistocene reefs from isolated carbonate platforms (Iles Eparses, SW Indian Ocean): A preliminary study

Isolated carbonate platforms occur throughout the geologic record, from Archean to present. Although the respective roles of tectonics, sediment supply and sea-level changes in the stratigraphical architecture of these systems are relatively well constrained, the details of the nature and controls on the variability of sedimentological patterns between and within individual geomorphologic units on platforms have been barely investigated. This study aims at describing and comparing geomorphological and sedimentological features of surficial sediments and fossil reefs from three isolated carbonate platforms located in the SW Indian Ocean (Glorieuses, Juan de Nova and Europa). These carbonate platforms are relatively small and lack continuous reef margins, which have developed only on windward sides. Field observations, petrographic characterization and grain-size analyses are used to illustrate the spatial patterns of sediment accumulation on these platforms. The internal parts of both Glorieuses and Juan de Nova platforms are blanketed by sand dunes with medium to coarse sands with numerous reef pinnacles. Skeletal components including coral, green algae, and benthic foraminifera fragments prevail in these sediments. Europa platform exhibits a similar skeletal assemblage dominated by coral fragments, with the absence of wave-driven sedimentary bodies. Fossil reefs from the Last interglacial (125,000 years BP) occur on the three platforms. At Glorieuses, a succession of drowned terraces detected on seismic lines is interpreted as reflecting the last deglacial sea-level rise initiated 20,000 years ago. These findings highlight the high potential of these platforms to study past sea-level changes and the related reef response, which remain poorly documented in the SW Indian Ocean.

Movement ecology of Indo-Pacific lionfish on Caribbean coral reefs and its implications for invasion dynamics

The spread of marine invasive species at large geographic scales depends largely on current-driven larval dispersal. However, at smaller spatial scales, movements occurring after larval settlement can greatly influence the success of local control programs. We conducted the first dedicated tracking study of Indo-Pacific lionfish (Pterois volitans and P. miles) on Caribbean coral reefs. Using a mark-resighting approach, we estimated the scale and frequency of movements of 79 tagged lionfish on patchy and continuous reefs to study factors influencing movement. Many tagged lionfish moved relatively little, with ~60 % of fish resighted at least once and 10 % not moving from their initial tagging location. However, maximum movements (as far as 1.35 km in 15 days) far exceeded previous estimates. Lionfish movement was density dependent, declined at larger body sizes, and depended on seascape structure. Lionfish on continuous reefs moved faster and more often than those on patch reefs, and lionfish in patchy habitats moved farther when patches were closer together. Invasions taking place over heterogeneous seascapes such as coral reefs are difficult to manage effectively with spatially uniform regional management plans, but understanding an invader’s movement ecology can help to optimize the distribution of limited resources for invasive management.

Self-recognition in corals facilitates deep-sea habitat engineering.

The ability of coral reefs to engineer complex three-dimensional habitats is central to their success and the rich biodiversity they support. In tropical reefs, encrusting coralline algae bind together substrates and dead coral framework to make continuous reef structures, but beyond the photic zone, the cold-water coral Lophelia pertusa also forms large biogenic reefs, facilitated by skeletal fusion. Skeletal fusion in tropical corals can occur in closely related or juvenile individuals as a result of non-aggressive skeletal overgrowth or allogeneic tissue fusion, but contact reactions in many species result in mortality if there is no ‘self-recognition’ on a broad species level. This study reveals areas of ‘flawless’ skeletal fusion in Lophelia pertusa, potentially facilitated by allogeneic tissue fusion, are identified as having small aragonitic crystals or low levels of crystal organisation, and strong molecular bonding. Regardless of the mechanism, the recognition of ‘self’ between adjacent L. pertusa colonies leads to no observable mortality, facilitates ecosystem engineering and reduces aggression-related energetic expenditure in an environment where energy conservation is crucial. The potential for self-recognition at a species level, and subsequent skeletal fusion in framework-forming cold-water corals is an important first step in understanding their significance as ecological engineers in deep-seas worldwide.

Movement, habitat utilization and behaviour of coral trout Plectropomus leopardus during and after the reproductive period on the southern Great Barrier Reef

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 496:33-45 (2014) - DOI: https://doi.org/10.3354/meps10645 Theme Section: Tracking fitness in marine vertebrates Movement, habitat utilization and behaviour of coral trout Plectropomus leopardus during and after the reproductive period on the southern Great Barrier Reef C. M. Bunt1,*, M. J. Kingsford2 1Biotactic Fish and Wildlife Research (Biotactic, Inc) 691 Hidden Valley Road, Kitchener, Ontario N2C 2S4, Canada 2School of Marine and Tropical Biology and ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville QLD 4811, Australia *Corresponding author: cbunt@biotactic.com ABSTRACT: Coral trout Plectropomus leopardus (mean total length = 498.9 ± 19.7 mm, n = 10) were tagged and tracked with ultrasonic transmitters over 81 d at an intra-lagoonal location at One Tree Island, Great Barrier Reef, Australia (23.4979°S, 152.0712°E). Movement and habitat preferences were compared during the transition between the reproductive and post-reproductive period. Overall, mean movement was highest between 05:00 and 10:00 h, with the most movement during the crepuscular period and the least movement at night. There was no difference in nighttime movement during or after the reproductive period. Mean daily movement (14.48 ± 0.26 km d-1) and fish depths (4.23 ± 0.02 m) during the post-reproductive period were significantly greater than both movement (10.63 ± 0.13 km d-1) and depths occupied (3.38 ± 0.01 m) during the reproductive period, which was likely related to reallocation of bioenergetic resources to foraging related activities rather than spawning. Most fish movement was localized (within 0.04 km2), with some movements recorded outside of this area to a maximum distance of 0.6 km. Fish traversed sand and small scattered coral out-croppings to reach areas of continuous reef. The ranges of movement and habitat preferences described in this study are important for future research on habitat requirements and behavioural changes across the transition period between reproductive and post-reproductive states. Furthermore, this study provides additional information that may be used for focusing and delineating species-specific Marine Protected Area management plans. KEY WORDS: Plectropomus leopardus · Serranidae · Movement · Habitat preference · Habitat requirements · Ultrasonic telemetry · Marine Protected Area Full text in pdf format PreviousNextCite this article as: Bunt CM, Kingsford MJ (2014) Movement, habitat utilization and behaviour of coral trout Plectropomus leopardus during and after the reproductive period on the southern Great Barrier Reef. Mar Ecol Prog Ser 496:33-45. https://doi.org/10.3354/meps10645 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 496. Online publication date: January 27, 2014 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2014 Inter-Research.

Monitoring an Alien Invasion: DNA Barcoding and the Identification of Lionfish and Their Prey on Coral Reefs of the Mexican Caribbean

BackgroundIn the Mexican Caribbean, the exotic lionfish Pterois volitans has become a species of great concern because of their predatory habits and rapid expansion onto the Mesoamerican coral reef, the second largest continuous reef system in the world. This is the first report of DNA identification of stomach contents of lionfish using the barcode of life reference database (BOLD).Methodology/Principal FindingsWe confirm with barcoding that only Pterois volitans is apparently present in the Mexican Caribbean. We analyzed the stomach contents of 157 specimens of P. volitans from various locations in the region. Based on DNA matches in the Barcode of Life Database (BOLD) and GenBank, we identified fishes from five orders, 14 families, 22 genera and 34 species in the stomach contents. The families with the most species represented were Gobiidae and Apogonidae. Some prey taxa are commercially important species. Seven species were new records for the Mexican Caribbean: Apogon mosavi, Coryphopterus venezuelae, C. thrix, C. tortugae, Lythrypnus minimus, Starksia langi and S. ocellata. DNA matches, as well as the presence of intact lionfish in the stomach contents, indicate some degree of cannibalism, a behavior confirmed in this species by the first time. We obtained 45 distinct crustacean prey sequences, from which only 20 taxa could be identified from the BOLD and GenBank databases. The matches were primarily to Decapoda but only a single taxon could be identified to the species level, Euphausia americana.Conclusions/SignificanceThis technique proved to be an efficient and useful method, especially since prey species could be identified from partially-digested remains. The primary limitation is the lack of comprehensive coverage of potential prey species in the region in the BOLD and GenBank databases, especially among invertebrates.

Dynamics of fish assemblages on a continuous rocky reef and adjacent unconsolidated habitats at Fernando de Noronha Archipelago, tropical western Atlantic

In recent years, many studies investigated how density-dependent factors, such as shortages in microhabitat and food availability influence the structure of reef fish assemblages. Most of what is currently known, however, comes from comparisons of isolated patch reefs and from correlations between fish abundance and one or few microhabitat variables. In addition, most studies were done in the Caribbean and Indo-Pacific regions, whereas the South Atlantic region has been, to date, understudied. The present study evaluated spatial and temporal variations in reef fish abundance and species richness in a continuous rocky reef and adjacent unconsolidated habitats in a Southwestern Atlantic reef, using underwater techniques to assess both fish numbers and microhabitat variables (depth, rugosity, number of crevices and percent cover of live benthic organisms, bare rock, sand, and limestone). Higher species richness was observed at consolidated substratum stations on both sampling periods (May and October), but fish abundance did not show a significant spatial variation. Topographical complexity and percent cover of algae (except coralline algae) were amongst the most important determinants of species richness, and correlations between fish size and refuge crevice size were observed. The non-random patterns of spatial variation in species richness, and to a lesser extent, fish abundance, were related to differences in substratum characteristics and the inherent characteristics of fishes (i.e. habitat preferences) and not to geographical barriers restraining fish movement. This study highlights the importance of concomitantly assessing several microhabitat variables to determine their relative influence in reef fish assemblages.

Microfacies analysis and paleoenviornmental interpretation of the Qom Formation, South of the Kashan, Central Iran

Qom Formation (Oligo-Miocene marine deposits, Central Iran) in the South of Kashan, was studied in order to determine its microfacies and depositional environment. Thirteen microfacies (MF A–M) were distinguished based on petrography, sedimentological features, components distribution and present fauna. According to recognized microfacies and absence of gravity deposits, real and continuous reef, barrier and storm structures, carbonate platform of the Qom Formation in South of Kashan developed on an open shelf without effective barriers separating it from the sea. The co-occurrences of miliolids and planktonic foraminifera in planktonic microfacies is the reliable evidences for absence of any reefal, oolitic and bioclastic barriers in depositional environment, and deposition of the study section on an open shelf, as in the absence of barrier, currents removed miliolids to deeper parts of sea (basin). Three major depositional environments were identified in the Oligo-Miocene succession in the study section, on the basis of the distribution of the foraminifera and vertical facies relationships. They include inner shelf, middle shelf and proximal outer shelf. Inner shelf includes MF A–G and characterized by abundant imperforate foraminifera. Middle shelf comprises MF H–J and characterized by association of larger benthic foraminifera with hyaline wall. Proximal outer shelf includes MF K–M and characterized by the presence of planktonic foraminifera and absence of larger benthic foraminifera, as well as abundance of light-independent, heterotroph organisms.

The influence of connectivity on richness and temporal variation of reef fishes

To test the effects of connectivity on fish diversity in isolated reef patches we deployed pairs of artificial reefs (AR) at constant distances (12 and 25 m) from a large continuous reef and added series of small ARs to half of them. These small reefs served as stepping-stones to increase fish movement between the large ARs and the continuous reef. Species gain and loss curves were compared to obtain deeper understanding of the underlying mechanisms in relation to the theory of island biogeography. We found that AR without stepping-stones maintained up to 57-fold more individuals than ARs with stepping-stones during mass recruitment events that were dominated by the family Apogonidae. However, in-between these mass recruitment events the overall impact of the stepping-stones on richness and abundance was small. By contrast, increasing distance from the continuous reef from 12 to 25 m increased fish richness, although this was confounded with time since AR deployment. Increase in richness with distance was predominantly caused by elevated species gain. Our results suggest that fish assemblages respond in distinct ways to two types of isolation: (1) Increased richness with distance from a continuous reef, and (2) increased fluctuation in abundance with decreased connectivity. The latter may be the outcome of accumulation and then abrupt emigrations of fishes from isolated reefs. This study confirms that the spatial setting of reef patches in relation to larger or continuous reefs alters fish assemblages, which may be important for planning AR deployments that maximizes diversity.