Spatial dynamics of the quantity and diversity of natural and artificial hard bottom habitats in the eastern Gulf of Mexico

Keenan, Sean F.; Switzer, Theodore S.; Knapp, Anthony R.; Weather, Eric J.; Davis, John Staige

doi:10.1016/j.csr.2021.104633

Cited by 10 publications

(18 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For spatial distribution, the resultant stratification scheme included depth strata as well as broad regional designations. Regional stratum boundaries, which divided the eastern Gulf of Mexico into three regions, broadly corresponded to previously identified ichthyofaunal breaks (Saul et al 2013; Matheson et al 2017) as well as spatial breaks in underlying habitat quality and quantity (Keenan et al 2022). Three distinct depth strata were also identified.…”

Section: Discussionsupporting

confidence: 59%

“…Habitat mapping data were analyzed to manually digitize polygon boundaries of individual reef features (i.e., those >2 m across) that were classified using a derivative of the geoform and surface geological components of the Coastal and Marine Ecological Classification Standard (Table 2; Federal Geographic Data Committee 2012). Additional details of natural reef habitat mapping and classification protocols can be found in Keenan et al (2018, 2022). During second‐stage site selection, a sampling unit containing natural reef habitat was randomly selected, and one or two individual reef features, at least 100 m apart, were selected for sampling.…”

Section: Methodsmentioning

confidence: 99%

“…During second-stage site selection, one individual artificial reef feature was selected for sampling. Additional details of artificial reef habitat mapping and classification protocols can be found in Keenan et al (2018Keenan et al ( , 2022.…”

Section: Fish and Wildlife Research Institute Artificial Reef Surveymentioning

confidence: 99%

See 2 more Smart Citations

Integrating assemblage structure and habitat mapping data into the design of a multispecies reef fish survey

et al. 2023

Self Cite

View full text Add to dashboard Cite

ObjectiveSince 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.MethodsWe 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.ResultSpatially, 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.ConclusionBased on these results, survey efforts were integrated as the Gulf Fishery Independent Survey of Habitat and Ecosystem Resources (G‐FISHER) in 2020.

show abstract

Section: Discussionsupporting

confidence: 59%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Integrating assemblage structure and habitat mapping data into the design of a multispecies reef fish survey

et al. 2023

Self Cite

View full text Add to dashboard Cite

show abstract

“…Note different y-axis scales. seafloor is covered in natural reefs (Keenan et al, 2022), which similarly helped refine previous natural reef coverage estimates that ranged from 13% (Jaap, 2015) based on Rohmann et al (2005) to 38% (Parker et al, 1983). While Keenan et al did not extrapolate artificial reef coverage across the eastern GOM, they did delineate both artificial and natural reefs from their seafloor mapping dataset that covered a subset of the eastern GOM.…”

Section: Discussionmentioning

confidence: 76%

Quantifying spatial extents of artificial versus natural reefs in the seascape

et al. 2022

View full text Add to dashboard Cite

With increasing human uses of the ocean, existing seascapes containing natural habitats, such as biogenic reefs or plant-dominated systems, are supplemented by novel, human-made habitats ranging from artificial reefs to energy extraction infrastructure and shoreline installments. Despite the mixture of natural and artificial habitats across seascapes, the distribution and extent of these two types of structured habitats are not well understood but are necessary pieces of information for ocean planning and resource management decisions. Through a case study, we quantified the amount of seafloor in the southeastern US (SEUS; 103,220 km2 in the Atlantic Ocean; 10 – 200 m depth) covered by artificial reefs and natural reefs. We developed multiple data-driven approaches to quantify the extent of artificial reefs within state-managed artificial reef programs, and then drew from seafloor maps and published geological and predictive seafloor habitat models to develop three estimates of natural reef extent. Comparisons of the extent of natural and artificial reefs revealed that artificial reefs account for substantially less habitat (average of two estimates 3 km2; <0.01% of SEUS) in the region than natural reefs (average of three estimates 2,654 km2; 2.57% of SEUS) and that this pattern holds across finer regional groupings (e.g., states, depth bins). Our overall estimates suggest that artificial reef coverage is several orders of magnitude less than natural reef coverage. While expansive seafloor mapping and characterization efforts are still needed in SEUS waters, our results fill information gaps regarding the extent of artificial and natural reef habitats in the region, providing support for ecosystem-based management, and demonstrating an approach applicable to other regions.

show abstract

“…Habitats were identified and classified via interpretation of imagery from standardized side‐scan sonar surveys (Keenan et al. 2018, 2022). Sampling grids intersecting with identified habitat were selected to sample each year following a stratified random design, with sampling effort proportional to available habitat within each region and depth stratum (nearshore, 10–36 m; offshore, 37–109 m; and deep, 110–180 m).…”

Section: Methodsmentioning

confidence: 99%

A Habitat‐Based, Fishery‐Independent Survey Using Actively Fished Hooked Gear Successfully Characterizes Reef Fish Populations in the Eastern Gulf of Mexico

Winner

Switzer

Keenan

et al. 2022

N American J Fish Manag

Self Cite

View full text Add to dashboard Cite

Recognized limitations of fishery‐dependent data under rapidly changing management regimes have resulted in significant effort during recent years to improve the availability of fishery‐independent data in the southeastern United States. These fishery‐independent surveys target numerous species and habitats with various sampling methods, including the use of trawls, longlines, gill nets, traps, and visual surveys. Although passively fished hooked gear (e.g., longlines) are often used to assess the abundance and life history of managed reef fishes, such types of gear are often limited by the habitats they can fish effectively and are species selective. To address these shortcomings, we developed and implemented an actively fished approach to provide fishery‐independent data: the repetitive timed‐drop hooked‐gear method (RTD method). Despite the high degree of standardization applied to the RTD method, important questions remain as to whether active fishing imparts strong angler variability that may reduce the utility of survey data. Accordingly, we analyzed data from 2014 to 2018 to evaluate potential angler bias and how angler‐associated variability compares to other factors often thought to be important predictors of reef fish abundance and community structure. During this study, 962 stations were sampled, representing a variety of artificial and natural reef habitats. In total, 5,770 fish were caught, representing 92 taxa. Sampling was conducted by 103 unique anglers, including 42 commercial or charter fishers and 61 scientists. Results from both population‐ and assemblage‐level analyses found that most of the variability in the catch could be explained by hook size, habitat, water depth, and year. Angler type was rarely correlated with reef fish abundance or assemblages. Our analyses suggest that the RTD method is effective in gathering fishery‐independent abundance and life history data for reef fishes in the eastern Gulf of Mexico and that the resulting data are not strongly biased by an angler effect.

show abstract

Spatial dynamics of the quantity and diversity of natural and artificial hard bottom habitats in the eastern Gulf of Mexico

Cited by 10 publications

References 30 publications

Integrating assemblage structure and habitat mapping data into the design of a multispecies reef fish survey

Integrating assemblage structure and habitat mapping data into the design of a multispecies reef fish survey

Quantifying spatial extents of artificial versus natural reefs in the seascape

A Habitat‐Based, Fishery‐Independent Survey Using Actively Fished Hooked Gear Successfully Characterizes Reef Fish Populations in the Eastern Gulf of Mexico

Contact Info

Product

Resources

About