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Interactions between bottlenose dolphin and recreational rod and reel fisheries are a complex issue for resource managers in the United States, which may impact anglers' catch and lead to dangerous situations for scavenging or depredating dolphins. To examine this issue, we analyzed data collected by observers on for-hire fishing vessels off the eastern U.S. Gulf Coast from 2009 to 2020. A generalized additive model indicated number of anglers, number of discarded fish, proximity to shore, prior scavenging events, type of released fish, and area fished were all significant predictors of scavenging by dolphins. The Florida panhandle had the highest odds of scavenging, while scavenging in the Big Bend and Tampa Bay has increased through time. The Florida panhandle is a wellknown area for illegal feeding of dolphins, suggesting human behavior may be influencing fisheries interactions. Model outputs indicate that dolphins are primarily cuing on fishing activity rather than number of discards, but are more likely to scavenge discards from the family Lutjanidae (snappers), which comprised 40% of observed discards but 80% of scavenging events. This study highlights factors influencing the frequency of dolphin scavenging events, guiding managers and scientists on additional studies and mitigation measures needed to address this issue. [ABSTRACT FROM AUTHOR]

Objective: Since 2010, three spatially disjunct reef fish video surveys have provided fishery‐independent data critical to the assessment and management of reef fishes in the Gulf of Mexico. Although analytical approaches have recently been developed to integrate data from these surveys into a single measure of relative abundance and size composition, a more parsimonious approach would be to integrate survey efforts under a single Gulf‐wide survey design. Accordingly, we conducted a retrospective analysis of historical video‐ and habitat‐mapping data to develop a novel stratified random sampling design for conducting surveys of natural and artificial reef habitats. Methods: We conducted a series of classification and regression tree analyses to delineate both spatial and habitat strata, and conducted simulations to assess the performance of an optimized survey design. Result: Spatially, classification and regression tree results identified three depth strata (10–25 m, >25–50 m, >50–180 m) and three regional strata (north‐central Gulf, Big Bend, southwest Florida) in the eastern Gulf. For both natural and artificial reefs, habitat strata were delineated based on a combination of relative relief (low, medium, high) and size of the individual reef feature, although reef scale differed markedly between natural (<100 m2, 100–1000 m2, >1000 m2) and artificial habitats (<25 m2, 25–100 m2, >100 m2). To optimize effort among sampling strata, effort was allocated proportionally based on a combination of habitat availability and managed‐species richness for each stratum. Simulation results indicated that relative median biases were <10% and relative median absolute deviations <30% on estimates of abundance for most species examined on natural reefs under the optimal design, except Greater Amberjack Seriola dumerili. These measures of bias and imprecision were similar or higher for most species simulated using simple random and stratified random survey designs. Estimated relative median bias and relative median absolute deviations were notably higher for artificial reef surveys. Conclusion: Based on these results, survey efforts were integrated as the Gulf Fishery Independent Survey of Habitat and Ecosystem Resources (G‐FISHER) in 2020. Impact statementData from reef fish video surveys were analyzed to develop a new survey design in the Gulf of Mexico. The new design provides better estimates of reef fish abundance from natural and artificial reef habitats and will improve the assessment and management of multiple reef fishes. [ABSTRACT FROM AUTHOR]

Lutjanid snappers are ubiquitous at reef sites in the northern Gulf of Mexico (Gulf), but the degree of niche overlap and basal resource utilization is unknown for most species. Muscle tissue for stable isotope analysis was opportunistically sampled from red snapper (Lujanus campechanus), gray snapper (Lutjanus griseus), lane snapper (Lutjanus synagris), and vermilion snapper (Rhomboplites aurorubens) recreational catches across the northern Gulf. A Bayesian mixing model used to compare resource utilization indicated that Lutjanids occupy niches with varying degrees of overlap among regions but maintain a consistent hierarchy in isotopic composition. Scale shifts among regions were likely due to differences in riverine outflow, nitrogen fixation, and anoxic zones that alter prey abundance or isotopic δ15N ratios. All four Lutjanid species had high percent contributions from particulate organic matter and benthic microalgae with little contribution by macroalgae to any species in any region. Ontogenetic shifts in stable isotope values were observed in most species indicating that size plays an important role in avoiding niche overlap due to intense competition for high-value prey items among congeners at isolated reef sites. Diet specialization is modest but likely plays an important role in avoiding complete niche overlap. [ABSTRACT FROM AUTHOR]

We investigated the relationship between aspartic acid d:l ratios and otolith-derived age estimates in Gulf of Mexico red snapper, Lutjanus campechanus (ages 1–26 years; R2 = 0.89) and Caribbean yellowtail snapper, Ocyurus chrysurus (ages 2–17 years; R2 = 0.84). The estimated racemization rate was 0.61 × 10−3 year−1 for red snapper and 1.28 × 10−3 year−1 for yellowtail snapper, reflecting temperature differences between study regions. Mean jackknifed error in ages predicted from aspartic acid d:l was 1.70 ± 0.39 years for red snapper and 1.57 ± 0.41 years for yellowtail snapper. Results suggest amino acid racemization may be an effective tool for direct age estimation and potentially age validation in fishes. [ABSTRACT FROM AUTHOR]

Coastal restoration projects to mitigate environmental impacts have increased global demand for sand resources. Unfortunately, these resources are often extracted from sand/shell banks on the inner continental shelf, resulting in significant alteration or loss of low‐relief reefs in coastal oceans. Experimental reefs (oyster shell, limestone rubble, composite) were deployed in the western Gulf of Mexico to assess their potential value as nurseries for newly settled reef fishes. Occurrence, abundance, and species richness of juvenile fishes were significantly higher on all three types of low‐relief reefs compared with unconsolidated sediment. Moreover, reefs served as nursery habitat for a range of reef fish taxa (angelfishes, grunts, sea basses, snappers, and triggerfishes). Red snapper (Lutjanus campechanus) was the dominant species present on all experimental reefs (100% occurrence), and mean density of this species was markedly higher on each of the three low‐relief reefs (>40.0 individuals/reef) relative to comparable areas over unconsolidated sediment (0.2 individuals). Our results suggest creation or restoration of structurally complex habitat on the inner shelf has the potential to markedly increase early life survival and expedite the recovery of exploited reef fish populations, and therefore may represent a critical conservation tool for increasing recruitment and maintaining reef fish diversity. [ABSTRACT FROM AUTHOR]

Factors potentially affecting fish discarding were evaluated for species managed under the Gulf of Mexico grouper-tilefish individual fishing quota (GT-IFQ) program. Thirteen commercially important species are managed under the GT-IFQ program. Some of the more commonly caught species in the program include red grouper (Epinephelus morio), gag (Mycteroperca microlepis), speckled hind (Epinephelus drummondhayi), golden tilefish (Lopholatilus chamaeleonticeps), and blueline tilefish (Caulolatilus microps). It is necessary to determine why discards are occurring to develop a future discard mitigation strategy. Logistic models were constructed using data from the Southeast Fisheries Science Center's (SEFSC) Reef Fish Observer Program (RFOP) with covariates of fish length, available allocation, gear type, calendar year quarter, and year to infer reasons for discarding. The results from RFOP models in conjunction with self-reported discard information from the SEFSC Supplemental Discard Logbook program determined that discarding due to fish length selection, not related to minimum a size limit, is occurring for golden tilefish, speckled hind, yellowedge grouper (Epinephelus flavolimbatus), and snowy grouper (Hyporthodus niveatus). Other dynamics such as multi-species quota discarding are likely responsible for discards of blueline tilefish. Based on the results of the study, potential changes to the GT-IFQ program such as additional flexibility measures were identified as potential management strategies for decreasing discards. A similar approach to inferring why discarding is occurring could be used in the other regions for more effective management promoting long-term sustainability of valuable fisheries. [ABSTRACT FROM AUTHOR]

The Gulf of Mexico reef fish complex is socioeconomically important and is exploited by a vertical line fishery capable of high resolution spatial targeting. Indices of abundance derived from fishery dependent catch-per-unit-effort (CPUE) data are an important input to the assessment of these stocks. Traditionally, these indices have been derived from standardized logbook data, aggregated at a coarse spatial scale, and are limited to generating predictions for observed spatiotemporal strata. Understanding how CPUE is spatially distributed, however, can help identify range contractions and avoid hyperstability or hyperdepletion, both of which can mask the true population dynamics. Vessel monitoring systems (VMS) can provide complete, high-resolution distributions of CPUE used to create abundance indices. Here we compare two methods — spatial averaging of VMS-derived catch and effort data and the result of generalized linear models applied to logbook data for generating indices, to evaluate the use of VMS-derived abundance indices in assessments of reef fish stocks. This work suggests that in fisheries where targeting occurs at very fine spatial scales, abundance indices derived from high-resolution, spatiotemporally complete data may more accurately reflect the underlying dynamics of the stock. [ABSTRACT FROM AUTHOR]

Few data exist to evaluate the performance or assess the potential impacts of hook regulations on catchability or selectivity of recreational fisheries in the northern Gulf of Mexico. The purpose of this study was to test the effects of hook type (circle vs. J hook) and hook size (1/0, 4/0, and 7/0) on catch composition, traumatic hooking, species-specific catches, and size-selectivity of red snapper, Lutjanus campechanus, and grey triggerfish, Balistes capriscus. Selectivity was estimated by conditioning size distributions from hook-specific catches against in situ size distributions observed with a remotely operated vehicle. Deep hooking (hook set in gills or beyond) was low in all hook treatments for red snapper (<10%) and grey triggerfish (<6%), but was generally higher with J hooks, especially for other fishes caught with the largest J hook (34%). Hook type did not significantly affect catches, but catches decreased significantly with increasing hook size in all groups except red snapper. Selectivity curves were dome-shaped for both focus species in all hook treatments and selection peaks were similar among treatments for red snapper. Peak selectivity was 78.1mm larger for J hooks than circle hooks for grey triggerfish. Overall, study results indicate that the circle hook regulation may have reduced traumatic hooking mortality by up to 50%, and that catchability is similar between hook types for both red snapper and grey triggerfish when controlling for hook size. Strong dome-shaped selection estimated for nearly all selectivity curves suggest logistic size-selectivity assumptions in assessment models are likely inappropriate for recreational sectors targeting red snapper or grey triggerfish. [ABSTRACT FROM AUTHOR]

Current efforts to value ecosystem services have contributed little to the valuation of natural capital, suggesting that in practice "nature is capital" primarily serves as a metaphor. We provide a theoretically motivated approach for recovering natural capital prices that expands beyond idealized management to encompass current, likely inefficient, management institutions. Theoretically consistent capital valuation requires adjusting for the net marginal productivity of the natural capital asset and price appreciation. We develop a numerical approach for approximating the value of capital that integrates estimates from ecology and economics. We employ the method to recover credible accounting prices for a pound of Gulf of Mexico reef fish as a capital asset under real-world management conditions. Our approach reveals the interdisciplinarity of natural capital valuation and the importance of understanding the feedbacks between the state of natural capital stocks, human behavior affecting these stocks, and the role of institutions in shaping that feedback. [ABSTRACT FROM AUTHOR]

Abstract: Red snapper (Lutjanus campechanus) are associated with artificial habitats in the Gulf of Mexico (GOM). However, fine-scale movements and use of artificial reefs by red snapper over diel periods is unclear. Both manual and passive telemetry were used to examine fine-scale movement patterns and residence time of red snapper around artificial habitats to evaluate the importance of these structures to this species. Red snapper (550–745mm TL; n =12) were manually tracked at artificial reefs in the northeastern GOM over 24-h periods. Fish stayed near the artificial reefs (<100m, with 75% of locations within 30m of the structure), but were significantly further from the reefs at night (mean=27.5m, SD=7.1) than day (mean=19.1m, SD=8.2). Based on manual tracking, home range and mean distance from the reef increased with fish size. These fish also showed long term residence of 332–958d based on passive acoustic monitoring. The close proximity of these fish to the reef over 24-h periods and the long-term residency provides evidence that these artificial reefs are important habitat for red snapper and should be considered an effective management tool. [Copyright &y& Elsevier]

The northeastern Gulf of Mexico contains some of the most diverse and productive marine habitat in the United States. Much of this habitat, located on the shelf edge in depths of 50 to 120 m, supports spawning for many economically important species, including groupers. Here, we couple acoustic surveys with georeferenced videography to describe the primary spatial and geologic features of spawning aggregation sites for four economically important species: gag (Mycteroperca microlepis), scamp (M. phenax), red grouper (Epinephelus morio), and red snapper (Lutjanus campechanus), with notes on fish distribution and abundance and spawning activities. We provide information on movement patterns of reef fish determined using acoustic telemetry. Finally, we discuss the possible coupling of geomorphology with hydrographic features to influence the overall productivity of the region and the importance of spatial fishery management in sustaining that productivity. [ABSTRACT FROM PUBLISHER]

A review of the published literature on coral fish epizootics and disease suggest that a variety of bacterial, viral, and fungal pathogens and several host-ectoparasite relationships can affect coral reef fishes and populations. Biotoxic organisms (e.g., Caulerpa), toxic dinoflagellates (e.g., Gambierdiscus and Prorocentrum), and bacterial infection by Streptococcus iniae have been most commonly cited as the etiologic agents associated with coral reef fish epizootics in the Tropical Western Atlantic and Gulf of Mexico. Reports of tumors and related lesions in coral reef fishes are relatively uncommon. A chronic iridoviral disease known as lymphocystis affects angelfish, wrasses, grunts, and many other species that inhabit coral reefs and certain rhabdoviruses are also known to cause mortality in angelfish. Other coral reef fishes, such as snappers and damselfishes seem most susceptible to neurofibrosarcomas and neurofibromas. A variety of protozoan and metazoan ectoparasites are commonly found on coral reef fishes. In most cases, these parasites are found in low numbers and under normal conditions cause few or minor pathogenic effects. However, recent research suggests a need to reconsider the role of parasitism in the mortality of coral reef fishes. There is growing evidence that the ecological relationships between reef fishes, ectoparasites, and cleaner fishes are important to overall functioning, survival, and the social structures of fishes on coral reefs. However, until such a time as the spatial variations in abundance and species distribution, rarity, temporal variations in reef fish populations, and mechanisms of disease transmission are understood, it will be difficult to assess the potential effects of disease on reef fish populations. [ABSTRACT FROM AUTHOR]

Non-lethal methods are sought to provide indices or measure of absolute abundance to fit fishery stock assessment models, including those computed for reef fishes. Calibrated scientific echosounders provide the foundation for stock assessments in low-diversity ecosystems but are hampered by complicated target strength responses in high diversity systems like coral and rocky reefs. Newly available broadband echosounders present advantages over narrowband predecessors including increased spatial resolution, increased signal to noise and spectral resolution; however, a better understanding of the sound scattering properties is necessary for operational use in surveys of diverse reef fish assemblages. To gain insight into the feasibility of implementing broadband techniques, we first model the frequency dependent backscatter of ecologically and commercially important species; results will aid our understanding of the backscattering as well as provide a supporting dataset to develop algorithms for classification of species/functional groups. Computed-tomography (CT) scans were performed on 149 individuals across reef fish species from the northeastern Gulf of Mexico to generate three-dimensional swim bladder models for estimation of morphometrics to input into numerical scattering models. Principal component analysis of the swim bladder morphology indicated significant variation among species; however, closely related species (confamilials) were not different. We employed boundary element method modeling to examine the frequency-dependent backscatter responses across a range of fish orientations (+/- 45°). Comparisons of frequency-dependent backscatter revealed strongest similarities between closely related species and greatest differences between more distantly related species or species groups. Patterns in the spectra have the potential to be used to classify targets toward species (or species group) for estimates of density from marine ecosystem acoustic surveys. Given that broadband echosounders are not yet commonplace, and many surveys in the region utilize narrowband echosounders, we also developed narrowband target strength – length relationships for six of the reef fish species with model fits ranging widely (r2 = 0.05 to 0.93). The potential utility of broadband echosounders to enhance ecosystem studies, or to develop fisheries-independent indices of abundance for use in stock assessment is discussed. [ABSTRACT FROM AUTHOR]

• No significant difference in measured species richness between methods. • Each method documented unique species. • Remotely Operated Vehicle more frequently detected five federally managed fish species. • Abundance estimates from diver surveys were up to an order of magnitude greater. • Method choice identified distinct communities. Non-extractive visual survey methods are commonly used to assess a variety of marine habitats. The use of Underwater Visual Census (UVC) by SCUBA divers is predominant; however, remotely acquired video data (e.g., cameras systems, remotely operated vehicles (ROVs), submersibles) are becoming more frequently used to acquire community data. Both remote and diver-based surveys are currently used to survey artificial reef habitat in the Northwestern Gulf of Mexico (GOM) and have associated error due to inherent method bias. Because survey methods that most accurately document the occurrence and estimated abundance of several important fisheries species are greatly needed in the GOM, we compared data collected on the same days and sites from both Roving Diver Surveys (RDS) and micro-ROV surveys conducted on reefed oil and gas platforms. The combined datasets identified a total of 56 species from 22 families, and there was no significant difference in measured species richness between a comprehensive 30 min ROV survey and RDS. Five species of federally managed fish in the GOM were more frequently detected by ROV, as were the majority of species in the Lutjanid and Carangid families. However, abundance estimates from RDS surveys were up to an order of magnitude greater. Multivariate analyses indicated that method choice affected community composition, with Lutjanids and Carangids driving the differences. These two fish families in particular are subject to method bias, probably due to inflated abundance estimates with RDS, or alternatively, deflated estimates from ROV. Although our ROV surveys more frequently detected important fisheries species and produced conservative abundance estimates, a further examination of species distributions on these high-relief platform reefs is needed to fully determine the most accurate survey method. In addition, the attraction and/or gear avoidance of certain species to underwater vehicles deserves further investigation. Overall, our data indicate these methods are viable but the choice of survey method can have implications for the management of certain species, and that careful consideration of methodology is necessary to most accurately document species of interest. [ABSTRACT FROM AUTHOR]