Bathymetric Features Research Articles

The effects of depth, distance, and the Mid-Atlantic Ridge on genetic differentiation of abyssal and hadal isopods (Macrostylidae)

The largest habitat on Earth, the abyssal oceans below 3500m depth, is commonly assumed to represent a continuous environment due to homogeneity of environmental factors and the lack of physical barriers. Yet, the presence of bathymetric features, such as Mid-Ocean Ridges, and hadal trenches provide a discontinuation. During the Vema-TRANSIT expedition in 2014/2015 to the tropical North Atlantic, a transatlantic transect was studied following the full extent of the Vema Fracture Zone in an east-west direction and including the Puerto Rico Trench (PRT).The aim of this study was to test whether large bathymetric features represent barriers to dispersal and may lead to differentiation and eventually speciation. In this study, these potential barriers included the Mid-Atlantic Ridge (MAR) and the transition (~ 3000m) from the hadal PRT to the adjacent abyss. Genetic differentiation and differences in community structure (species composition) from east and west of the MAR, as well as abyssal and hadal depth zones were tested for using the poor dispersers Macrostylidae (Crustacea, Isopoda) as a modelDistribution patterns showed that certain macrostylid species have ranges extending more than 2000km, in some cases across oceanic ridges and trench-abyss transitions. Contrastingly, there was a clear signal for geographic population structure coinciding with the east-west division of the Atlantic by the MAR as well as with the abyss-hadal zonation. These results support the hypotheses that depth gradients as well as oceanic ridges reduce dispersal even though barriers may not be absolute. Additionally, positive correlation between genetic- and geographic distances showed that the vast size of the deep sea itself is a factor responsible for creating diversity.

Reshaping the Antarctic Circumpolar Current via Antarctic Bottom Water Export

AbstractZonal momentum input into the Antarctic Circumpolar Current (ACC) by westerly winds is ultimately removed via topographic form stress induced by large bathymetric features that obstruct the path of the current. These bathymetric features also support the export of Antarctic Bottom Water (AABW) across the ACC via deep, geostrophically balanced, northward flows. These deep geostrophic currents modify the topographic form stress, implying that changes in AABW export will alter the ocean bottom pressure and require a rearrangement of the ACC in order to preserve its zonal momentum balance. A conceptual model of the ACC momentum balance is used to derive a relationship between the volume export of AABW and the shape of the sea surface across the ACC’s standing meanders. This prediction is tested using an idealized eddy-resolving ACC/Antarctic shelf channel model that includes both the upper and lower cells of the Southern Ocean meridional overturning circulation, using two different topographic configurations to obstruct the flow of the ACC. Eliminating AABW production leads to a shallowing of the sea surface elevation within the standing meander. To quantify this response, the authors introduce the “surface-induced topographic form stress,” the topographic form stress that would result from the shape of the sea surface if the ocean were barotropic. Eliminating AABW production also reduces the magnitude of the eddy kinetic energy generated downstream of the meander and the surface speed of the ACC within the meander. These findings raise the possibility that ongoing changes in AABW export may be detectable via satellite altimetry.

Statistics of bottom-diffracted surface-reflected arrivals in ocean acoustics

Bottom-diffracted surface-reflected (BDSR) arrivals are a ubiquitous feature in long-range ocean acoustic propagation and are not predicted by existing forward models based on available bathymetric and bottom properties data. In a research cruise in the North Pacific in 2013 over 40 distinct bottom diffractor locations were identified within a 25 km radius survey (at least one diffractor location every 50 square kilometers). The BDSRs can be characterized in terms of: (a) grazing angle of the incident field, (b) in-plane or out-of-plane diffractors, (c) frequency (transmissions were made from 77.5 to 310 Hz), (d) receiver type (vertical or horizontal seismometer, hydrophone, etc.), (e) receiver location, (f) signal strength relative to direct and water multiple paths, and (g) location relative to bathymetric features. In this talk, we present the statistics of the BDSRs in terms of these criteria. This information will inform efforts to predict and exploit BDSRs and will be valuable in planning future cruises to identify the geologic features responsible for them. [Work supported by ONR.]

A biologically relevant method for considering patterns of oceanic retention in the Southern Ocean

Many marine species have planktonic forms – either during a larval stage or throughout their lifecycle – that move passively or are strongly influenced by ocean currents. Understanding these patterns of movement is important for informing marine ecosystem management and for understanding ecological processes generally. Retention of biological particles in a particular area due to ocean currents has received less attention than transport pathways, particularly for the Southern Ocean. We present a method for modelling retention time, based on the half-life for particles in a particular region, that is relevant for biological processes. This method uses geostrophic velocities at the ocean surface, derived from 23years of satellite altimetry data (1993–2016), to simulate the advection of passive particles during the Southern Hemisphere summer season (from December to March). We assess spatial patterns in the retention time of passive particles and evaluate the processes affecting these patterns for the Indian sector of the Southern Ocean. Our results indicate that the distribution of retention time is related to bathymetric features and the resulting ocean dynamics. Our analysis also reveals a moderate level of consistency between spatial patterns of retention time and observations of Antarctic krill (Euphausia superba) distribution.

Morphodynamics of a tidal ridge system in the southwestern Yellow Sea: HF radar study

A radial tidal ridge system is present throughout the coastal waters of the southwestern Yellow Sea (China) with varied and complicated ridges and channels between them. A newly designed ground-wave high-frequency (HF radar), with full-coverage and high spatial-temporal resolution, was employed in this study to measure the surface currents and bathymetric features correlated wave celerity in the study area from July 17 to August 6, 2011. We found that the spatial distribution pattern of the tidal channels is generally stable with periodic adjustments during a spring-neap tidal cycle and with higher degree of spatial orderliness from neap to spring tides than from spring to neap tides; the nearshore part of the channels is most stable in lateral, the middle part is relatively lateral unstable, and the offshore part changes complicatedly; flood-dominated channels and ebb-dominated ridges are identified using HF radar signals. The horizontal Kelvin number (Keh) is workable in lateral stability evaluation. This study reveals the potential of HF radar in morphodynamic studies on shallow coastal waters.

Utilizing the R/V Marcus G. Langseth's streamer to measure the acoustic radiation of its seismic source in the shallow waters of New Jersey's continental shelf.

Shallow water marine seismic surveys are necessary to understand a range of Earth processes in coastal environments, including those that represent major hazards to society such as earthquakes, tsunamis, and sea-level rise. Predicting the acoustic radiation of seismic sources in shallow water, which is required for compliance with regulations designed to limit impacts on protected marine species, is a significant challenge in this environment because of variable reflectivity due to local geology, and the susceptibility of relatively small bathymetric features to focus or shadow acoustic energy. We use data from the R/V Marcus G. Langseth’s towed hydrophone streamer to estimate the acoustic radiation of the ship’s seismic source during a large survey of the shallow shelf off the coast of New Jersey. We use the results to estimate the distances from the source to acoustic levels of regulatory significance, and use bathymetric data from the ship’s multibeam system to explore the relationships between seafloor depth and slope and the measured acoustic radiation patterns. We demonstrate that existing models significantly overestimate mitigation radii, but that the variability of received levels in shallow water suggest that in situ real-time measurements would help improve these estimates, and that post-cruise revisions of received levels are valuable in accurately determining the potential acoustic impact of a seismic survey.

Energetics of eddy‐mean flow interactions in the Brazil current between 20°S and 36°S

AbstractThe energetics of eddy‐mean flow interactions in the Brazil Current (BC) between 20°S and 36°S are investigated in 19 transects perpendicular to the 200 m isobath. Ten years (2000–2009) of output data from the Hybrid Coordinate Ocean Model (HYCOM) NCODA reanalysis, with a spatial resolution of 1/12.5° and 5 day averages, are used. The mean kinetic energy (MKE) and eddy kinetic energy (EKE) fields presented the same subsurface spatial pattern but with reduced values. The EKE increases southward, with high values along the BC path and the offshore portion of the jet. The values of the barotropic conversion term (BTC) are highest in the surface layers and decreased with depth, whereas the values of the baroclinic conversion term (BCC) and the vertical eddy heat flux (VEHF) are highest in the subsurface. Despite the vertical thickening of the BC, the highest energy conversion rates are confined to the upper 700 m of the water column. The energetic analysis showed that the current features mixed instability processes. The vertical weighted mean of the BTC and BCC presented an oscillatory pattern related to the bathymetry. The eddy field accelerates the time‐mean flow upstream and downstream of bathymetric features and drains energy from the time‐mean flow over the features. The BC is baroclinically unstable south of 28°S, and the highest energy conversion rates occur in Cabo de São Tomé, Cabo Frio, and the Cone do Rio Grande.

Demersal fish assemblages in the boreo-Arctic shelf waters around Svalbard during the warm period 2007–2014

The temporal and spatial resilience of abundance patterns of assemblages of organisms inhabiting transition zones between Arctic and boreal regions is an issue of concern in relation to climate change. The recognition that baseline information spanning such transition zones is required to facilitate future monitoring and assessments of temporal dynamics provided the motivation for the present study. One such transition area is the Svalbard archipelago of the Northeast Atlantic, located between the Arctic and the boreal Atlantic, where significant climate changes occur. The study aimed to utilize an existing data series from Svalbard to analyse and describe demersal fish assemblage structure and distributions. Norwegian bottom trawl surveys sampled the area annually in August–September 2007–2014, and the dataset is the first from this area which is sufficiently comprehensive to carry out assemblage analyses. The survey years analysed represent the recent unprecedented warm period in the Barents Sea–Svalbard region which started around 2004. The new baseline information improves the basis for future studies of resilience under changing environmental conditions. A key finding was that the major transition in species composition is that between deep Greenland Sea and Arctic Ocean assemblages (upper slope assemblages) and the shelf assemblages. In shallower shelf areas (<500 m depth) structuring is weaker with assemblages having many species in common. The expected association of fish assemblages with regional bathymetric and hydrographic features was confirmed. The observed patterns probably reflect a comparatively extensive Atlantic influence during the warm period.

Inexpensive Video Drop-camera for Surveying Sensitive Benthic Habitats: Applications from Glass Sponge (Hexactinellida) Reefs in Howe Sound, British Columbia

Where marine waters are shallow and bathymetric features are steep, the typically employed multi-beam side scan sonar is not always reliable for identifying complex biological structures. Here, we present a cost-efficient method used in Howe Sound, British Columbia, for bathymetric mapping, exploration, and ground-truthing of glass sponge bioherms. A simple depth sounder and software package was used to produce bathymetric maps. From these maps, prospective sites were selected and surveyed to investigate bioherm presence with a simple drop-camera towed off the bow of a small drifting vessel during calm seas. This method was used during a 4-year citizen science initiative that led to the discovery of 12 glass sponge bioherms in Howe Sound, the first step in protecting these globally unique reefs from the impact of bottom-contact fishing, anchoring, and potential industrial contamination. Before our work using this method, only two glass sponge bioherms had been identified in Howe Sound. The method also proved effective as a means to quantify damage to bioherms from fishing gear.

A Late Cretaceous mixed (turbidite-contourite) system along the Uruguayan Margin: Sedimentary and palaeoceanographic implications

The Late Cretaceous is a critical period in the evolution of the South Atlantic. Significant changes in the tectonic configuration of continental landmasses and marine basins during this time lead to major shifts in the sedimentary and oceanographic regimes. Using a combination of 2D and 3D seismic data with well data from the Uruguayan Margin, this work provides a new, highly detailed description of the Late Cretaceous sedimentary evolution of the margin and its regional and global palaeoceanographic implications.The Polonio Drift System (PDS), occupies the middle to lower-slope of the Uruguayan Margin. The PDS is characterised by four channel-drifts, which propagate obliquely (120–170°) from the palaeoslope and exhibit over 800m of local relief relative to the surrounding seafloor. Seismic interpretation identified four seismic units (SU.1–SU.4), separated by five major discontinuities (R.1–R.5). These record the onset (Albian–upper Turonian, 113–89.8Ma), growth (Coniacian–upper Maastrichtian, 89.8–66Ma), and burial (Paleocene, 66–56Ma) phases for the PDS. During the onset stage, down-slope processes dominate but, three major shifts in the sedimentary stacking pattern occur. These coincide with palaeoceanographic changes in the South Atlantic during the Cenomanian–Turonian (100.5–89.9Ma), Campanian-Maastrichtian (83.6–66Ma) and Paleocene (66–56Ma), following the opening of the Falkland/Malvinas-Agulhas Seaway (FAS), the subsidence of the Walvis-Ridge and the opening of the Vema channel. Bottom current influence first occurs during the growth stage (Coniacian–Campanian) when mounded deposits shift from aggradational and slightly progradational towards the N (SU.2), to clear lateral migration towards the S (SU.3). This sedimentary pattern indicates a regional palaeoceanographic shift in bottom current flow from northerly, to a subsequent southerly direction. Bottom currents do not appear to have actively eroded sediment, although they apparently had the potential to pirate and entrain fine-grained material from turbidity plumes, which build on underlying bathymetric features such as basement horsts and channel-levees. These produce large mounded morphologies adjacent to channels. Drift growth ceases following the termination of shelf progradation (R.4), enabling sluggish bottom currents contributed to a homogeneous sedimentary drape. Bottom currents intensify in the beginning of the Paleocene, forming contourite depositional systems with well-developed contourite terrace along the middle slope. Further research can elucidate the nature and mechanics of turbidite–contourites interactions along continental margins. This work offers new insights for the implications and consequences of the interaction of turbidites and contourites, which can improve the characterisation of deep-water deposits and understanding palaeoceanographic interpretations.

THE STRUCTURE OF NEARSHORE CURRENTS DRIVEN BY CHANGES IN METEO-MARINE FORCINGS

This work aims to better understand the physical processes governing the wave propagation in a vertically sheared current and the resulting nearshore circulation patterns. It is based on a high resolution hydro-morphodynamic field campaign, ROUSTY2014, collecting a comprehensive hydro-morphodynamical dataset during a full winter season. The overall analysis highlights three main circulation patterns, largely controled by the bathymetric features and by co-working or competing wind and waves forcings. Regarding the vertical structuration of the circulation, most of field observations shown seaward directed circulation with onshore component close to the air/sea surface whose intensity varies according to incoming wave conditions. Forth, vertical shear increase when breaking happen close to sensor location and orientation of mean circulation depend on wind direction.

Circulation and water mass transports on the East Antarctic shelf in the Mertz Glacier region

The East Antarctic shelf off Adélie-George V Land is known to be an important region for Dense Shelf Water (DSW) formation as a result of intense sea ice production in the Mertz Glacier Polynya during the winter season. It is also a region where the warm modified Circumpolar Deep Water (mCDW) penetrates onto the shelf during the summer. Using hydrographic observations from a summer survey in 2008 we implement a box inverse model to propose a comprehensive view of the steady state circulation on this shelf in summer. Additional information from mooring observations collected on the depression slope is used to provide context to the retrieved circulation scheme. Over the depression slope, the summer baroclinic structure of the currents is found to contrast with the almost barotropic structure in winter.The summer circulation is strongly constrained by the DSW distribution and forms a clockwise circulation primarily transporting the fresh surface waters and the warm mCDW around the dome of DSW. Over the upper flank of the Mertz Bank, the inflow branch transports the mCDW towards the Mertz Glacier, while, over the lower part of the slope, the outflow branch returns to the sill a diluted mode of the same water mass. A total of 0.19Sv of mCDW inflows at the sill and two-third reach the Mertz Glacier and recirculate in front of it, allowing the mCDW to penetrate into the deeper part of the depression. Possible scenarios of interaction between the mCDW and the DSW with the glacier are examined. It is shown that, despite the water mass pathways and transports suggest possible ice-ocean interaction, both lateral and basal melting were likely small in summer 2008. Finally, our results suggest that, in addition to bathymetric features, the distribution of the residual DSW which is left from the preceding winter sets up regional pressure gradients which provide a seasonal control on the shelf circulation. In particular, the spring collapse of the convective patch would contribute to setting up a deep pycnocline which strongly impacts the shelf circulation in the following summer, with possible feedback of the mCDW transports on the polynya activity and water mass formation.

Three-dimensional modeling in global acoustic propagation

The ocean is nearly transparent for acoustic propagation at low frequencies (&amp;lt;100 Hz), leading to the detection of signals (seismic events, volcanoes, and man-made signals) at distances as large as the ocean basin. Historically, basin acoustic modeling has neglected out-of-plane effects and has been performed with the model computed in the range/depth plane for multiple radials following geodesics (Nx2D). Both oceanographic and bathymetric features can lead to out-of-plane effects. In this paper, a summary of computational approaches to this problem will be presented, including vertical-mode, horizontal ray hybrid approaches, and full-3D Parabolic Equation modeling. Out-of-plane effects include refraction and diffraction—which have different effects as well as different approaches to modeling. Experiments where 3D propagation effects were significant will be presented within this context, including Perth-Bermuda (1960), the Heard Island Feasibility Test (1993), and a recent seismic tomography test off the coast of Japan (2015). Three physics mechanisms will be addressed: horizontal deflection due to mesoscale eddies and fronts, reflection from islands (refraction), and diffraction behind bathymetric edges.

Characteristics of bottom-diffracted surface-reflected arrivals in ocean acoustics

Bottom-diffracted surface-reflected (BDSR) arrivals are a ubiquitous feature in long-range ocean acoustic propagation. BDSRs are distinct from bottom-reflected surface-reflected (BRSR) arrivals because the angle of emergence is not equal to the angle of incidence. They are not predicted by existing forward models based on available bathymetric and bottom properties data. Research cruises in the Philippine Sea and North Pacific, in 2011 and 2013, respectively, were carried out to understand BDSRs in more detail for transmissions out to 50 km range. Transmissions from a controlled source at about 60m depth were received on ocean bottom seismometers and a deep vertical line array of hydrophones. In the North Pacific experiment alone over 40 distinct bottom diffractor locations were identified. Based on these data sets BDSRs can be characterized in terms of: (a) in-plane or out-of-plane diffractors, (b) diffractor location relative to bathymetric features, c) grazing angle of the incident field, d) transmission frequency (from 75 to 310 Hz), (e) receiver type (vertical or horizontal seismometer, hydrophone, etc.), (f) receiver location, and (g) signal strength relative to direct and BRSR paths. [Work supported by ONR.]

New Perspectives on Frontal Variability in the Southern Ocean

AbstractThe frontal structure of the Southern Ocean is investigated using the Wavelet/Higher Order Statistics Enhancement (WHOSE) frontal detection method, introduced in Chapman’s work. This methodology is applied to 21 yr of daily gridded absolute dynamic topography (ADT) data to obtain daily maps of the locations of the fronts. By forming frontal occurrence frequency maps and then approximating these occurrence maps by a superposition of simple functions, the time-mean locations of the fronts, as well as a measure of their capacity to meander, are obtained and related to the frontal locations found by previous studies. The spatial and temporal variability of the frontal structure is then considered. The number of fronts is found to be highly variable throughout the Southern Ocean, increasing (splitting) downstream of large bathymetric features and decreasing (merging) in regions where the fronts are tightly controlled by the underlying topography. These splitting/merging events are related to changes in the underlying frontal structure whereby regions of high frontal occurrence cross or spread over streamfunction contours. In contrast to the number of fronts, frontal meandering remains relatively constant throughout the Southern Ocean. Little to no migration of the fronts over the 1993–2014 time period is found, and there is only weak sensitivity of frontal positions to atmospheric forcing related to the southern annular mode or the El Niño–Southern Oscillation. Finally, the implications of these results for the study of cross-stream tracer transport are discussed.

Wavelet Galerkin scheme for solving nonlinear dispersive shallow water waves: Application in bore propagation and breaking

An accurate and fast numerical method is developed to investigate the nonlinear (linear) shallow water wave propagation over flat (depth-varying) topography in one space dimension within an irrotational and inviscid flow. As physical model, we use a dispersive Boussinesq-type (BT) system for small-amplitude long waves with weak transverse variation. The problem is discretised in space using a wavelet-Galerkin method based on one-periodic Daubechies scaling functions. Assuming periodic boundary conditions, the discretised operators in spatial domain are circulant and skew-symmetric. These characteristics of discretised differential operators allow us to incorporate the Fast Fourier Transformation (FFT) in the matrix operations which results in a substantial improvement in the computational efficiency and accuracy of the numerical solver compared with the conventional finite difference or finite volume methods. We use a four-stage Runge–Kutta method to temporally discretise the governed spatially discretised differential equations. Several comparative test cases are conducted to validate the performance and efficiency of the proposed wavelet-Galerkin scheme for the BT model over flat beds relative to some existing analytical solutions and numerical results from a second-order finite difference method. We examine the numerical results of the BT system to investigate the two-way propagation of waves for some large L2-norm profiles of the initial free-surface elevation. We also assess the ability of the proposed method to predict the evolution and breaking of undular bores over a flat bed with a simple kinematic criterion. Moreover, we study (tsunami) wave runup and propagation by incorporating the effects of depth-varying topography in a simplified BT system in order to check the applicability of the approach to capture the interactions between the bathymetric features and the wet cells.

Physical linkages between an offshore canyon and surf zone morphologic change

AbstractThe causes of surf zone morphologic changes observed along a sandy beach onshore of a submarine canyon were investigated using field observations and a numerical model (Delft3D/SWAN). Numerically simulated morphologic changes using four different sediment transport formulae reproduce the temporal and spatial patterns of net cross‐shore integrated (between 0 and 6.5 m water depths) accretion and erosion observed in a ∼300 m alongshore region, a few hundred meters from the canyon head. The observations and simulations indicate that the accretion or erosion results from converging or diverging alongshore currents driven primarily by breaking waves and alongshore pressure gradients. The location of convergence or divergence depends on the direction of the offshore waves that refract over the canyon, suggesting that bathymetric features on the inner shelf can have first‐order effects on short‐term nearshore morphologic change.

Acoustical methodology for determination of gas content in aquatic sediments, with application to Lake Kinneret, Israel, as a case study

The spatial distribution of gaseous methane in the top layer of the sediment of Lake Kinneret (the Sea of Galilee), Israel is quantified using a novel acoustical methodology. Measurements were carried out with low-frequency sound pulses (200 Hz–2 kHz) for different depths of the lake along the offshore transects. The methodology is based on the correlation of gas content with sound speed and, in turn, with the reflection coefficient of sound waves from sediment. Variations in the free gas content in sediments with water depth obtained using the proposed method show a remarkable agreement with the distribution of organic matter content in and methane fluxes from sediment, both revealed by the preceding studies. This spatially variable pattern can be explained by the specific biogeochemical, hydrodynamic, and bathymetric characteristics of Lake Kinneret. The suggested method is especially suitable for characterizing gassy sediments and highlighting the location of potential methane emissions.

Modeling hydrodynamics of large lagoons: Insights from the Albemarle-Pamlico Estuarine System

Large estuaries are influenced by winds over adjacent coastal ocean and land areas causing significant spatial variations in water levels, currents and surface waves. In this study we apply a numerical model to simulate hydrodynamics and waves in the Albemarle-Pamlico Estuarine System, a large and shallow back-barrier basin in eastern North Carolina, over a one-month study period (September 2008) with observations from several storm wind events of differing time scales and directions. Model performance is evaluated for a spatially varying wind field from the North American Regional Reanalysis (NARR) dataset in comparison to spatially uniform forcing from wind observations at offshore, coastal and land-based sites across the region. A spatially uniform wind field from offshore winds observations results in statistically better hydrodynamic simulations of water levels (R = 0.88) in the estuaries than NARR (R = 0.48) after comparison with measurements and indicates the importance of strong marine winds over most of the estuary surface area.The influence of a prominent bathymetric feature on hydrodynamics in Pamlico Sound is also investigated by numerically removing a 30 km long and 2–3 m deep shoal from the model grid and replacing it with an idealized depth of 6 m. The removal of the shoal increases water level setup by 14% at the estuarine shoreline, decreases current magnitudes by up to 40% in the shoal region and increases significant wave heights locally by up to 25% in the sound, indicating the importance of this relict geomorphic feature as a major control on the hydrodynamic response of the system during wind events. The results suggest that increasing the water depth over the shoal can lead to higher storm surges and wave heights with the possibility of increased inundation and erosion of the back-barrier and mainland coastal regions. The complex bathymetry and marine wind influence are critical input conditions for modeling large and shallow lagoonal estuaries like the Albemarle-Pamlico Estuarine System.

Timing and locations of reef fish spawning off the southeastern United States.

Managed reef fish in the Atlantic Ocean of the southeastern United States (SEUS) support a multi-billion dollar industry. There is a broad interest in locating and protecting spawning fish from harvest, to enhance productivity and reduce the potential for overfishing. We assessed spatiotemporal cues for spawning for six species from four reef fish families, using data on individual spawning condition collected by over three decades of regional fishery-independent reef fish surveys, combined with a series of predictors derived from bathymetric features. We quantified the size of spawning areas used by reef fish across many years and identified several multispecies spawning locations. We quantitatively identified cues for peak spawning and generated predictive maps for Gray Triggerfish (Balistes capriscus), White Grunt (Haemulon plumierii), Red Snapper (Lutjanus campechanus), Vermilion Snapper (Rhomboplites aurorubens), Black Sea Bass (Centropristis striata), and Scamp (Mycteroperca phenax). For example, Red Snapper peak spawning was predicted in 24.7–29.0°C water prior to the new moon at locations with high curvature in the 24–30 m depth range off northeast Florida during June and July. External validation using scientific and fishery-dependent data collections strongly supported the predictive utility of our models. We identified locations where reconfiguration or expansion of existing marine protected areas would protect spawning reef fish. We recommend increased sampling off southern Florida (south of 27° N), during winter months, and in high-relief, high current habitats to improve our understanding of timing and location of reef fish spawning off the southeastern United States.