Flower Garden Banks National Marine Sanctuary Research Articles

Coral disease outbreak at the remote Flower Garden Banks, Gulf of Mexico

East and West Flower Garden Bank (FGB) are part of Flower Garden Banks National Marine Sanctuary (FGBNMS) in the northwest Gulf of Mexico. This geographically-isolated reef system contains extensive coral communities with the highest coral cover (>50%) in the continental United States due, in part, to their remoteness and depth, and have historically exhibited low incidence of coral disease and bleaching despite ocean warming. Yet in late August 2022, disease-like lesions on seven coral species were reported during routine monitoring surveys on East and West FGB (2.1–2.6% prevalence). A series of rapid response cruises were conducted in September and October 2022 focused on 1) characterizing signs and epidemiological aspects of the disease across FGB and within long-term monitoring sites, 2) treating affected coral colonies with Base 2B plus amoxicillin, and 3) collecting baseline images through photostations and photomosaics. Marginal and/or multi-focal lesions and tissue loss were observed, often associated with substantial fish and invertebrate predation, affecting the dominant coral species Pseudodiploria strigosa (7–8% lesion prevalence), Colpophyllia natans (11–18%), and Orbicella spp. (1%). Characterizing this disease event during its early epidemic phase at East and West FGB provides a critical opportunity to observe how coral disease functions in a relatively healthy coral ecosystem versus on reefs chronically affected by various stressors (e.g., Caribbean reefs adjacent to urban centers). Insights into the etiology, spread, and impacts of the disease can ultimately inform efforts to mitigate its effects on coral communities.

Fish community characterization of mid-shelf and shelf- edge mesophotic coral ecosystems in the expanded Flower Garden Banks National Marine Sanctuary

The mid to outer continental shelf in the northern Gulf of Mexico is composed of a patchy distribution of coral and rock reefs designated high priority for marine protection. To better understand the influence of deepwater habitat on fish community dynamics and conservation needs, we compared altiphotic-mesophotic transition (20– 40 m), upper mesophotic (40–60 m), and middle mesophotic (60–80 m) fish communities between mid-shelf (Sonnier Bank) and outer-shelf (McGrail Bank) banks from before their inclusion into the Flower Garden Banks National Marine Sanctuary. Surveys performed over two years with a remotely operated vehicle indicated that each bank and depth zone had distinct fish communities. Both banks were dominated by planktivores and piscivores, with an increase in depth specialists (e.g., deepwater anthiids and serranids) at the deeper zones surveyed, particularly in middle mesophotic depths at McGrail. An increased frequency of snappers, groupers, and amberjack was observed at Sonnier Bank, predominately in mesophotic depths, indicating the Sonnier Mesophotic Coral Ecosystem as either a hotspot or potential refuge for meso- and apex predators. This study fills a temporal gap in fish community dynamics of these two banks, serving to create a more continuous dataset available to assist in conservation assessments of the Flower Garden Banks National Marine Sanctuary.

Key Life History Attributes and Removal Efforts of Invasive Lionfish (Pterois volitans) in the Flower Garden Banks National Marine Sanctuary, Northwestern Gulf of Mexico

Indo-Pacific lionfish (Pterois volitans and P. miles) are the first marine teleost to have successfully invaded and become established in the Western Atlantic Ocean of the United States, Gulf of Mexico (GoM), and Caribbean Sea. Pterois volitans were first reported in the Flower Garden Banks National Marine Sanctuary (FGBNMS), a protected coral reef system in the northwestern GoM, in 2011. Little is understood about the life history characteristics of lionfish in this ecosystem. This study assessed population characteristics (size, density, age and growth) and removal efforts of lionfish (n = 1,665) at two coral reef sites within FGBNMS for 2015, 2016, and 2018. The annual increment formation in sagittal otoliths was examined to assess the age and growth of lionfish collected in 2018 (n = 100). Lionfish ranged in size from 75 to 444 mm total length (TL) and 4–1,153 g in total weight (TW). Six hundred and ten fish were randomly dissected for sex determination (females = 256, males = 354), females ranged in size from 137 to 348 mm TL and 21–586 g, while males ranged from 118 to 444 mm TL and 18–1,153 g. Interannual variation in mean lionfish density ranged from 26.7 individuals per hectare (ind ha–1) in 2016 to 81.1 ind ha–1 in 2018, while removal effort significantly increased ranging from 1.92 to 5.42 kg diver h–1. Lionfish age ranged from 0 to 10 years, with a mean age of 3.9 years. The observed values of the asymptotic maximum total length (L∞) and Brody’s growth coefficient (K) were 345 mm and 0.30 for females and 415 mm and 0.18 for males. Results suggest lionfish from FGBNMS exhibit markedly lower mean densities, a lower L∞ and growth rate, but attain older ages than lionfish in the Caribbean Sea, Western Atlantic Ocean, and other ecoregions in the northern GoM. This study describes the first key life history parameters and removal efforts for lionfish in a protected, healthy coral reef system in the northwestern GoM that may provide insight into environmental population controls (e.g., ecological resilience). Metrics from this study could be integrated into mechanistic ecological models to determine if FGBNMS is in fact exhibiting natural resilience to the lionfish invasion.

Gene expression associated with disease resistance and long-term growth in a reef-building coral.

Rampant coral disease, exacerbated by climate change and other anthropogenic stressors, threatens reefs worldwide, especially in the Caribbean. Physically isolated yet genetically connected reefs such as Flower Garden Banks National Marine Sanctuary (FGBNMS) may serve as potential refugia for degraded Caribbean reefs. However, little is known about the mechanisms and trade-offs of pathogen resistance in reef-building corals. Here, we measure pathogen resistance in Montastraea cavernosa from FGBNMS. We identified individual colonies that demonstrated resistance or susceptibility to Vibrio spp. in a controlled laboratory environment. Long-term growth patterns suggest no trade-off between disease resistance and calcification. Predictive (pre-exposure) gene expression highlights subtle differences between resistant and susceptible genets, encouraging future coral disease studies to investigate associations between resistance and replicative age and immune cell populations. Predictive gene expression associated with long-term growth underscores the role of transmembrane proteins involved in cell adhesion and cell–cell interactions, contributing to the growing body of knowledge surrounding genes that influence calcification in reef-building corals. Together these results demonstrate that coral genets from isolated sanctuaries such as FGBNMS can withstand pathogen challenges and potentially aid restoration efforts in degraded reefs. Furthermore, gene expression signatures associated with resistance and long-term growth help inform strategic assessment of coral health parameters.

Morphological and molecular characterization of a new species of black coral from Elvers Bank, north-western Gulf of Mexico (Cnidaria: Anthozoa: Hexacorallia: Antipatharia: Aphanipathidae: Distichopathes)

AbstractThe continental shelf edge of the NW Gulf of Mexico supports dozens of reefs and banks, including the West and East Flower Garden Banks (FGB) and Stetson Bank that comprise the Flower Garden Banks National Marine Sanctuary (FGBNMS). Discovered by fishermen in the early 1900s, the FGBs are named after the colourful corals, sponges and algae that dominate the region. The reefs and banks are the surface expression of underlying salt domes and provide important habitat for mesophotic coral ecosystems (MCE) and deep coral communities to 300 m depth. Since 2001, FGBNMS research teams have utilized remotely operated vehicles (e.g. ‘Phantom S2’, ‘Mohawk’, ‘Yogi’) to survey and characterize benthic habitats of this region. In 2016, a Draft Environmental Impact Statement proposed the expansion of the current sanctuary boundaries to incorporate an additional 15 reefs and banks, including Elvers Bank. Antipatharians (black corals) were collected within the proposed expansion sites and analysed using morphological and molecular methods. A new species, Distichopathes hickersonae, collected at 172 m depth on Elvers Bank, is described within the family Aphanipathidae. This brings the total number of black coral species in and around the sanctuary to 14.

Coral bleaching and recovery from 2016 to 2017 at East and West Flower Garden Banks, Gulf of Mexico

East Flower Garden Bank (EFGB) and West Flower Garden Bank (WFGB), part of Flower Garden Banks National Marine Sanctuary (FGBNMS) in the northwestern Gulf of Mexico, support tropical coral reefs that exhibit over 50% living coral cover. These reefs have been monitored annually since 1989, and in 2016 were exposed to higher than normal seawater temperatures leading to a severe bleaching event. Corals at EFGB and WFGB showed no signs of bleaching until September 2016, occurring later in the year compared to other reefs in the Caribbean region. Coral bleaching and subsequent recovery at each bank were documented through a time series of repetitive photographs within previously established long-term monitoring stations. Preceding the event, mean live coral cover within monitoring stations was collectively 64 ± 2%. Prior to signs of bleaching from July to September 2016, seawater temperatures on the reef were above 30 °C for a total of 36 d at EFGB and 21 d at WFGB. By October 2016, 67 ± 5% of the coral cover within EFGB monitoring stations and 25 ± 3% within WFGB monitoring stations exhibited signs of bleaching or paling stress, with dissimilarities in the amount of bleaching most likely due to significant differences in thermal profiles between banks. Significantly increasing long-term trends for daily mean seawater temperature indicate that temperatures on the banks have become warmer over time, and calculated bleaching threshold curves suggest that more than 50 d above 29.5 °C would initiate a bleaching year at EFGB and WFGB. Even though recovery within monitoring stations at both banks was documented with no significant declines in mean coral cover from 2016 to 2017 (64% and 62%, respectively), it is likely FGBNMS will be subject to additional and more frequent bleaching events in the future as ocean temperatures continue to rise.

Correction to: Important juvenile manta ray habitat at Flower Garden Banks National Marine Sanctuary in the northwestern Gulf of Mexico

In a recent paper (Stewart et al. 2018), we reported on the presence of juvenile manta rays in the Flower Garden Banks National Marine Sanctuary (FGBNMS) and suggested that the region serves as a nursery habitat for the species. Unfortunately we failed to consider the Masters thesis by Jeffrey N Childs (2001) entitled: ‘The occurrence, habitat use, and behavior of sharks and rays associating with topographic highs in the Northwestern Gulf of Mexico’. Childs (2001) was the first to document the presence of juvenile manta rays at the Flower Garden Banks and he suggested that the Flower Garden Banks serve as a nursery habitat for juvenile manta rays. We regret this oversight and apologize for failing to acknowledge and cite this relevant work.

Seasonal variability of carbonate chemistry and decadal changes in waters of a marine sanctuary in the Northwestern Gulf of Mexico

Abstract We report seasonal water column carbonate chemistry data collected over a three-year period (late 2013 to 2016) at Flower Garden Banks National Marine Sanctuary (FGBNMS) located on the subtropical shelf edge of the northwestern Gulf of Mexico. The FGBNMS hosts the northernmost tropical coral species in the contiguous United States, with over 50% living coral cover. Presented here are results from samples of the upper 25 m of the water column collected from September 2013 to November 2016. Additionally, following a localized mortality event likely associated with major continental flooding in summer 2016, water samples from up to ~250 m depth were collected in the broader FGBNMS area on a rapid response cruise to examine the seawater carbonate system. Both surface (

Important juvenile manta ray habitat at Flower Garden Banks National Marine Sanctuary in the northwestern Gulf of Mexico

Oceanic manta rays (Mobula birostris) are large pelagic planktivores that are threatened globally by targeted fisheries and bycatch. While studies of oceanic mantas have increased substantially in the past decade, major knowledge gaps remain in their basic biology, ecology and life history. The juvenile stage in particular is virtually unstudied, as juvenile oceanic mantas are rarely observed in the wild and are known primarily from fisheries and captive individuals. Here, we present evidence suggesting that Flower Garden Banks National Marine Sanctuary (FGBNMS) is an important habitat for juvenile manta rays. Recent genetic evidence indicates that both oceanic mantas and a proposed third manta species (Mobula cf. birostris) are present at FGBNMS. Size estimates of mantas sighted at FGBNMS over 25 years of monitoring efforts indicate that 95% of individuals are smaller than the size at maturity for male M. birostris, and 80% are smaller than the size at maturity for M. alfredi. Photographic records of juvenile males with undeveloped claspers further corroborate these findings. Temporal patterns of use and the prevalence of juveniles suggest that this region may serve as nursery habitat for M. birostris and M. cf. birostris. Further research is necessary to determine the importance of the region to juveniles of each species, as well as long-term patterns of habitat use and residency.

Assessment of Mesophotic Coral Ecosystem Connectivity for Proposed Expansion of a Marine Sanctuary in the Northwest Gulf of Mexico: Larval Dynamics

While there are several areas containing shallow coral habitats in the Gulf of Mexico (GOM), the availability of suitable reef habitat at mesophotic depths (~30–150 m) along the continental shelf margin suggests the potential for ecologically connected coral populations across hundreds of kilometers in the northwest (NW) GOM. The NW GOM includes a relatively high proportion of mesophotic habitats, including salt diapirs in Flower Garden Banks National Marine Sanctuary (FGBNMS), Bright Bank, and McGrail Bank, the latter two being Habitat Areas of Particular Concern (HAPCs). In response to a proposed expansion plan for the sanctuary boundaries to include additional mesophotic banks in the NW GOM, we investigated the genetic connectivity of the depth-generalist coral Montastraea cavernosa, a ubiquitous member of scleractinian communities throughout the Tropical Western Atlantic. M. cavernosa populations in the NW GOM demonstrated strong connectivity with relatively high levels of gene flow and no significant genetic differentiation occurring over banks up to 120 km apart. Historical migration models based on genetic data predicted panmixia of M. cavernosa across the NW GOM. The comparisons between genetic and biophysical models (see Garavelli et al., 2018; associate manuscript) highlight not only the importance of incorporating multiple assessments of connectivity into management schemes, but also the potentially stochastic nature of oceanographic patterns in the NW GOM and their effect on migration estimates among coral habitats. These trends indicate that M. cavernosa populations have remained well-connected in the NW GOM and that coral populations on each bank have likely been receiving larval recruitment through time. Thus, M. cavernosa populations should be managed as a combined unit within the NW GOM, which supports the proposal to expand the NMS boundaries to include mesophotic habitats beyond West and East FGB.

Assessment of Mesophotic Coral Ecosystem Connectivity for Proposed Expansion of a Marine Sanctuary in the Northwest Gulf of Mexico: Population Genetics

While there are several areas containing shallow coral habitats in the Gulf of Mexico (GOM), the availability of suitable reef habitat at mesophotic depths (~30–150 m) along the continental shelf margin suggests the potential for ecologically connected coral populations across hundreds of kilometers in the northwest (NW) GOM. The NW GOM includes a relatively high proportion of mesophotic habitats, including salt diapirs in Flower Garden Banks National Marine Sanctuary (FGBNMS), Bright Bank, and McGrail Bank, the latter two being Habitat Areas of Particular Concern (HAPCs). In response to a proposed expansion plan for the sanctuary boundaries to include additional mesophotic banks in the NW GOM, we investigated the genetic connectivity of the depth-generalist coral Montastraea cavernosa, a ubiquitous member of scleractinian communities throughout the Tropical Western Atlantic. M. cavernosa populations in the NW GOM demonstrated strong connectivity with relatively high levels of gene flow and no significant genetic differentiation occurring over banks up to 120 km apart. Historical migration models based on genetic data predicted panmixia of M. cavernosa across the NW GOM. The comparisons between genetic and biophysical models (see Garavelli et al., 2018; associate manuscript) highlight not only the importance of incorporating multiple assessments of connectivity into management schemes, but also the potentially stochastic nature of oceanographic patterns in the NW GOM and their effect on migration estimates among coral habitats. These trends indicate that M. cavernosa populations have remained well-connected in the NW GOM and that coral populations on each bank have likely been receiving larval recruitment through time. Thus, M. cavernosa populations should be managed as a combined unit within the NW GOM, which supports the proposal to expand the NMS boundaries to include mesophotic habitats beyond West and East FGB.

Gambierdiscus (Dinophyceae) species diversity in the Flower Garden Banks National Marine Sanctuary, Northern Gulf of Mexico, USA

Globally, ciguatera fish poisoning (CFP) is the principal cause of non-bacterial illness associated with seafood consumption. The toxins (ciguatoxins) responsible for CFP are produced by dinoflagellates in the genus Gambierdiscus, which are endemic to tropical and sub-tropical areas. Ciguatoxins are lipophilic and bioaccumulate in marine food webs, typically reaching their highest concentrations in fish. Following a CFP event in 2008, the U.S. Food and Drug Administration (USFDA) issued a ciguatera toxin alert that included fish harvested in the northern Gulf of Mexico in and near the Flower Garden Banks National Marine Sanctuary (FGBNMS). The East Flower Garden Bank (EFGB) and West Flower Garden Bank (WFGB) are characterized by thriving coral communities that support Gambierdiscus growth. This study was undertaken specifically to document the diversity of Gambierdiscus species present in the sanctuary that may be sources of ciguatoxins entering the food web. Samples collected from the FGBNMS over a three year period were screened using species-specific polymerase chain reaction assays. A diverse assemblage of Gambierdiscus species was distributed to depths of >45m, a new depth record for Gambierdiscus. Gambierdiscus belizeanus, Gambierdiscus caribaeus, Gambierdiscus carolinianus, Gambierdiscus carpenteri and Gambierdiscus ribotype 2 were all found on both East and West FGB with Gambierdiscus ruetzleri also recorded from the WFGB. The most common species was G. carolinianus, originally identified from samples collected between 35 and 40m off the coast of NC, USA. Our findings are consistent with recent physiological studies showing that some Gambierdiscus species can grow year round at the temperatures and salinities at the FGBNMS and at light levels as low as 10μmolphotonsm−2s−1. Such irradiances are estimated to occur in the FGBNMS at depths of ∼70–80m. The consistent recovery of Gambierdiscus species from deep sampling sites in areas known to produce ciguatoxic fish signals a substantial change in our concept of suitable habitats for Gambierdiscus to include depths greater than 50m.

Commercial fisheries in the northwestern Gulf of Mexico: possible implications for conservation management at the Flower Garden Banks National Marine Sanctuary

Abstract Levesque, J. C. 2011. Commercial fisheries in the northwestern Gulf of Mexico: possible implications for conservation management at the Flower Garden Banks National Marine Sanctuary. – ICES Journal of Marine Science, 68: 2175–2190. Marine resource managers designate marine protected areas (MPAs) to conserve, protect, and enhance fragile marine resources. A form of MPAs sometimes used by resource managers in the United States is a national marine sanctuary (NMS), and for all MPAs, managers need to use updated information during sanctuary management plan reviews (MPRs). In 2006, the Flower Garden Banks NMS (FGBNMS) began its first MPR by conducting public hearings and soliciting comments. Some 66% of comments were about the potential impacts fisheries posed to the sanctuary, so a description of commercial fishery activity in the NW Gulf of Mexico can help guide resource managers make sound, informed decisions. Despite limitations on data and knowledge of fishing effort spatially for the FGBNMS, commercial landings vary by Gulf state, area, and fishing gear, with most landings from the Louisiana and Texas coasts taken with trawls and nets. The main species landed from the NW Gulf of Mexico are shrimp, yellowfin tuna, and red snapper. Some conservation measures proposed for the FGBNMS will likely impact some commercial fisheries (hook and line, bottom longline), but not others (otter trawl, pelagic longline).

Recreational Fisheries and Marine Protected Area Management: Marine Policy and Environmental Management of the Flower Garden Banks National Marine Sanctuary (USA)

The demand on our marine resources is increasing at unsustainable rates; however, marine policy and management is complex, political, and time consuming. One tool that resource managers in the United States use for managing, protecting, and conserving fragile marine resources is the designation of Marine Protected Areas. Presently, the public is concerned with the status and health of the fish and fisheries associated with the Flower Garden Banks National Marine Sanctuary (FGBNMS). Given these conservation and social issues, the main goal of this study was to provide an evaluation of the recreational fisheries associated with the FGBNMS. Findings showed that recreational landings were dominated by red snapper, vermilion snapper, and gray triggerfish; landings varied significantly by month and location. The highest fishing effort was in summer and the highest catch rates were in spring and fall; catch rates varied significantly by species and location in some areas. The mean weight of the primary recreational species taken was correlated negatively with time, but statistical similar. Proposed management measures for the FGBNMS are expected to impact some recreational fisheries, but long-term outcomes should benefit the Gulf of Mexico ecosystem.

Coral Bleaching Susceptibility Is Decreased following Short-Term (1–3 Year) Prior Temperature Exposure and Evolutionary History

Coral exposed to short periods of temperature stress (≥1.0°C above mean monthly maximum) and/or increased frequencies of high temperatures may bolster resilience to global warming associated with climate change. We comparedMontastraea cavernosa(Linnaeus, 1767; Cnidaria, Scleractinia, Faviidae) from the Florida Keys National Marine Sanctuary (FKNMS) and the Flower Garden Banks National Marine Sanctuary (FGBNMS). Thermal stress has been reported frequently within the FKNMS; however, corals in the FGBNMS experience nominal exposures to similar stressors. Corals were exposed to three temperatures (27°C, 31°C, and 35°C) for 72 h. Colonies from the FKNMS lost significantly fewer viable and necrotic zooxanthellae under conditions of acute stress (35°C) than the FGBNMS colonies. This indicates that the FKNMS corals are less temperature-sensitive than those in the FGBNMS. The observed differences point to greater prior temperature exposure and adaptation in the former versus the latter site when correlated to previous years of thermal exposure.

A New Species of Halichoeres (Teleostei: Labridae) from the Western Gulf of Mexico

A new labrid fish, Halichoeres burekae, is described from specimens collected at Stetson Bank, Flower Garden Banks National Marine Sanctuary (FGBNMS), in the northwestern Gulf of Mexico over claystone, sponge, and coral substrata. The bright purple, blue-green, and yellow body coloration, and anterior black pigmentation of the dorsal fin in the terminal male, large black irregular spot at the base of the caudal peduncle, salmon body coloration, yellow snout in the initial stage/female, and diagnostic differences in the mitochondrial DNA cytochrome b gene separate this species from all other western Atlantic labrids. Adult H. burekae were observed in small schools along the reef crest mixed with Thalassoma bifasciatum and Chromis multilineata, and small juveniles were observed in mixed schools with juvenile Clepticus parrae. It feeds primarily on calanoid copepods and other plankton and is a close relative of H. socialis from Belize. This species is currently known from the FGBNMS and reefs off Veracruz, Mexico, in the western Gulf of Mexico.

Fish assemblages on artificial and natural reefs in the Flower Garden Banks National Marine Sanctuary, USA

Visual censusing was used to characterize fish assemblages on artificial and natural reefs located within the boundaries of the Flower Garden Banks National Marine Sanctuary (FGBNMS) in the northwestern Gulf of Mexico. Emphasis was placed on determining spatial and temporal patterns in habitat utilization by fishes on an offshore artificial reef (Mobil Platform HI-A389A). Overall, 43 species were observed during diurnal surveys in the upper 24 m of the artificial reef. Midwater pelagic fishes (i.e., carangids and scombrids) accounted for over 50% of all taxa enumerated on the artificial reef; however, these taxa were transient members of the assemblage and were observed infrequently. Labrids, pomacentrids, and serranids were the dominant reef-dependent taxa. Distinct trends in vertical, diel, and seasonal abundances were observed for juvenile and adult fishes. Of the three designated depth zones (upper 1.5–9.0, middle 9.0–16.5; lower 16.5–24.0 m), abundance and species diversity were lowest in the upper zone. Nocturnal counts were characterized by a marked reduction or complete absence of most species, due in part to twilight cover-seeking and movement activities. Seasonal variation in community composition and species abundance (May versus September) was primarily due to recruitment of juveniles (0-age fishes) to the artificial reef in late summer. Increases in total fish abundance (all taxa combined) coincided with both increasing habitat rugosity and degree of fouling. Species richness on natural coral reefs in the FGBNMS was higher than on the artificial reef. Unlike the artificial reef, fish assemblages on the natural reefs were dominated by a single family (Pomacentridae) which accounted for over 50% of all individuals observed.