DREDGING SUMMIT & EXPO ’18 PROCEEDINGS

SPATIAL INTERPOLATION AS A TOOL TO ASSESS THE EFFECTS OF OCEAN DISPOSAL ON ECONOMICALLY IMPORTANT SPECIES: GOLDEN TILEFISH HABITAT AT MIAMI ODMDS AS A CASE STUDY

Jason C. Seitz 1

ABSTRACT Spatial interpolation, such as ordinary kriging and inverse distance weighting (IDW), can be used in conjunction with existing sediment sampling results as a cost-effective way of predicting the effects of long-term dredged material disposal on economically important fisheries at ocean disposal sites. Predicting disposal effects on golden tilefish habitat in and around the Miami ODMDS is used as an example. ANAMAR and Harbor Branch Oceanographic Institute determined that golden tilefish inhabited the ODMDS and surrounding area in 1986 prior to most disposal events by analyzing archived ROV video data. Since 1986, at least 7.9 million m3 of dredged material have been deposited at the ODMDS, including gravel and limestone rubble. The amounts and types of material deposited call into question the suitability of the substrate for these large inhabitants of soft sediment.

Results of ordinary kriging interpolation predicted the sediment over approximately 10.6 km2 to be composed of >30% silt and clay, including most of the Miami ODMDS, suggesting that this area remained suitable for golden tilefish. An area of 1.0 km2 within the ODMDS and extending slightly north had ≤30% silt and clay composition and may be less suitable for golden tilefish. IDW results were similar to those of kriging, with approximately 10.3 km2 of the predicted area being well suited for golden tilefish and the remaining 1.4 km2 being poorly suited for this species. Areas now containing limestone rubble and gravel may be better suited for snappers and groupers.

Kriging uses weighted linear combinations of data having a mean prediction error equal to 0 and strives to minimize the variance of errors. For this reason, kriging is categorized as one of the best linear interpolation unbiased predictors. IDW is an exact interpolation method that assigns a weight to each point as an inverse proportion of the distance between the nearest points.

Spatial interpolation is a cost-effective first step towards understanding the effects of long-term disposal of dredged sediment on economically important inhabitants of ODMDSs. Similar disposal sites off Fort Lauderdale and Key West are located along the upper continental slope in probable golden tilefish habitat. These methods can be used to begin to understand the relationship between material placement and fisheries habitation. Additionally, it is recommended that fisheries managers and agencies tasked with ODMDS management (i.e., EPA, USACE) exchange information and recommendations to increase awareness of potential impacts to fisheries and establish strategies to avoid or ameliorate such impacts.

Keywords: kriging, inverse distance weighting, disposal effects, habitat management, Lopholatilus chamaeleonticeps

INTRODUCTION Habitat management is not often considered by fisheries managers when assessing the status of a given stock, despite its long-lasting effects on a fishery (Arlinghaus et al. 2002, Cooper 2006). Coastal development has altered Florida’s estuaries with dredge-and-fill and channelization projects, beach armoring has affected the littoral zone throughout the state, and southern Florida’s water resources have been re-allocated (Livingston 1990). Habitat modification, such as impoundments, affect fisheries worldwide and may even impair recovery efforts for imperiled species such as the smalltooth sawfish (Pristis pectinata) (Seitz and Poulakis 2006). Even deepwater fisheries stocks, such as tilefishes (Malacanthidae), are not immune to habitat alteration.

Sediments dredged from navigational channels during construction or maintenance are often disposed of at ocean dredged material disposal sites (ODMDSs) designated by the U.S. Environmental Protection Agency (EPA) and co- managed by the U.S. Army Corps of Engineers (USACE) under §103 of the Marine Protection, Research, and Sanctuaries Act of 1972 (MPRSA) (33 USC §1413). An average of 162,085,630 m3 of dredged material were annually dumped at U.S. disposal sites during fiscal years 2008 through 2012 (USACE 2015). Much of this material went to

1 Senior Biologist, ANAMAR Environmental Consulting, Inc, 2106 Northwest 67th Place, Suite 5, Gainesville, Florida 32653, USA, T: 352-377-5770 ext. 116, Email: [email protected].

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ODMDSs. Of the 131 or more ODMDSs that received EPA approval (Kamlet 1983), at least 99 have been permitted since the MPRSA was enacted in 1972 (EPA 2018).

Very little is known of the effects of offshore disposal activities on nearby benthic communities. The available literature focuses largely on the effects on hard-bottom assemblages (Crowe et al. 2010) due to the large number of species of fisheries interest that utilize reef habitat. Little is known about the effects of disposal activities on economically important inhabitants of soft-bottom communities, such as golden tilefish (Lopholatilus chamaeleonticeps).

In 2010, USACE Jacksonville District hired ANAMAR Environmental Consulting to characterize the benthic habitats (suspected by USACE to include tilefish habitat) within video data captured during a January 1986 remotely operated vehicle (ROV) benthic habitat survey conducted by Conservation Consultants, Inc. as part of the formal designation of the Miami ODMDS. The Miami ODMDS encompasses a 3.4-km2 (1-nmi2) area located 8.7 km (4.7 nmi) off Miami Beach, Florida, along the upper continental slope in water 127 to 235 m deep (mean depth = 180 m) (Figure 1).

Figure 1. The Miami ODMDS and surrounding study area (17.5 km2 [5.1 nmi2]) located off Miami Beach (Miami-Dade County), Florida. The study area is positioned along the upper continental slope in water depths of 122 to 253 m (including 127 to 235 m within the Miami ODMDS). Sources: Miami ODMDS coordinates from EPA (2001); landforms from U.S. Census Bureau, 1:100,000; bathymetry from National Oceanic and Atmospheric Administration (NOAA) Coastal Services Center.

ANAMAR and Harbor Branch Oceanographic Institute (HBOI) collaborated in characterizing the benthic habitats within the ROV study area. The benthic video was captured using a Recon IV ROV and the research vessel Seward Explorer. A Hydrostar Underwater Navigation System was used to operate the ROV. International Underwater Contractors operated the ROV while Conservation Consultants, Inc. conducted the video survey. The ROV study

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consisted of four parallel video transects (VT-1 through VT-4) running northward at distances of 3.84 to 7.01 km (2.07 to 3.78 nmi) each. The four transects covered water depths of 122 to 253 m and traversed a combined total of 22.8 km (12.3 nmi) in and around the Miami ODMDS. A total of 17.8 hours of recorded video data were submitted to USACE Jacksonville District along with a figure illustrating the transect lines and a list of coordinates and ship positions taken every 2 minutes. The ROV videographic study area encompassed a 17.5-km2 (5.1-nmi2) rectangular area (Figure 2) containing all four transects and the Miami ODMDS.

Figure 2. The results of four ROV video transects (VT-1 through VT-4) conducted during January 1986 by Conservation Consultants (1986) and reviewed by ANAMAR and HBOI (2010) revealed two golden tilefish (Lopholatilus chamaeleonticeps) observations and numerous tilefish burrows within the 17.5-km2 (5.1-nmi2) study area. The dense mounds habitat devoid of tilefish are attributed to overfishing rather than environmental constraints. Sources: ROV transects from Conservation Consultants (1986); tilefish and burrow observations from ANAMAR and HBOI (2010); Miami ODMDS coordinates from EPA (2001); bathymetry from NOAA Coastal Services Center.

The purpose of this study was to (1) predict the long-term cumulative impacts of dredged material disposal on golden tilefish habitat within the 17.5-km2 (5.1-nmi2) survey area, including the Miami ODMDS, using a cost-effective spatial interpolation approach; (2) address the possible presence of other federally managed taxa based on the spatial interpolation results and recent physical analysis data; (3) generate a visual representation of golden tilefish habitat in

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one or more maps of the study area; and (4) formulate recommendations for dredging stakeholders and fisheries agencies using an integrative framework.

1986 Pre-disposal Conditions Analysis of the ROV video footage revealed that substrate along the four transects consisted almost exclusively of sand and fine sediments (silts and clays). The substrate composition in the video data was verified by comparing it to the results of analysis of sediment samples collected in 1985, which showed a sediment composition of roughly three parts fine sand to one part silt or clay (Conservation Consultants 1985). Thousands of depressions observed were attributed to golden tilefish based on collaborations with numerous specialists and descriptions of golden tilefish burrows in the literature (Grimes et al. 1986; Able et al. 1987, 1993). Burrow diameters were also noted and were categorized as either medium (approximately 30–50 cm) or large (51–150 cm).

Overall, 81.7% of the transected seafloor had burrows attributed to golden tilefish, ranging from 49.5% for VT-2 to 100% for VT-1 and VT-3. Only VT-3 had sightings of golden tilefish (Figure 3). Mean golden tilefish burrow density (mean number of burrows/1,000 m2) ranged from 115 burrows/1,000 m2 at VT-3 to 419 burrows/1,000 m2 at VT-1, with a mean of 244 burrows/1,000 m2 for all transects. The occurrence of these burrows along transects combined with the substrate, bottom temperature, and depth data indicated that the entire 17.5-km2 (5.1-nmi2) study area (including the ODMDS) contained suitable golden tilefish habitat during the time of the video survey (Figure 2). Additional species of management interest observed in the ROV video included snowy grouper (Hyporthodus niveatus), silk snapper (Lutjanus cf. vivanus), and golden crab (Chaceon fenneri) (ANAMAR and HBOI 2010).

Figure 3. Golden tilefish (Lopholatilus chamaeleonticeps) and associated burrow from ROV video transects.

Off Florida’s east coast, golden tilefish show very specific habitat preference for substrates having high clay or silt content in water 137–290 m deep with an average bottom temperature of 8.6° to 15.4°C (Able et al. 1993, Able 2002, Dooley 2002). This large demersal species is non-migratory, spending most of its life associated with large burrows (to 1.5 m diameter off Florida) that it constructs and maintains (Grimes et al. 1986). The clay or silt component is necessary for the sediment to be malleable for burrow construction and maintenance. The burrows are used as shelter for the tilefish but are also important for commensal invertebrate and fish species, including commercially important species such as golden crab, for shelter and foraging (Grimes et al. 1986).

Predicting the Status of Golden Tilefish Habitat Following Disposal Activities: The Next Step Since the 1986 ROV video data were collected, at least 7.9 million m3 of material have been deposited at the Miami ODMDS (USACE 2018) (Table 1). This material includes approximately 2.9 million m3 of sand and limestone rubble as part of Phase 3 of the Port of Miami deepening project (EPA and USACE 2008). By September 2008, approximately 3.1 million m3 of the dredged material deposited at the Miami ODMDS was characterized as having a gravel and limestone rubble component (EPA and USACE 2008). The amount and types of material deposited call into question the suitability of the substrate for golden tilefish given the species’ preference for soft sediment.

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Table 1. Dredged material volumes disposed of at the Miami ODMDS per event for the period 1986–2015 following the January 1986 ROV survey. Year of Volume Disposed Dredge Transport Site Event 1 (m3) (cy) Project Type Method Method Management 1990 172,025 225,000 Federal, maintenance Hopper Hopper Hopper 1993 188,845 247,000 (not recorded) — — — 1995 229 300 Federal, maintenance Mechanical Scow Scow 1995 2,294 3,000 (not recorded) — — — 1996 1,529,110 2,000,000 Federal, maintenance Hopper Hopper Scow 1999 611,644 800,000 (not recorded) — — — 2005 1,030,620 1,348,000 Federal, maintenance Hopper Hopper Hopper 2006 206,430 270,000 Federal, new work Mechanical Scow Scow 2013 319,011 417,250 Federal, new work Hopper Hopper Hopper 2014 491,462 642,808 Permitted, new work Mechanical Scow Scow 2014 1,587,245 2,076,038 Permitted, new work Hydraulic Hopper Scow 2015 1,804,449 2,360,130 Permitted, new work Mechanical Scow Scow Total 7,943,364 10,389,526 1 Post-2015 disposal data was not available at the time of writing. Source: USACE (2018) (https://odd.el.erdc.dren.mil/ODMDSSearch.cfm)

MATERIALS AND METHODS Sediment-profile-imaging (SPI) results from 58 stations sampled in May 2006 in and around the Miami ODMDS and presented by Germano & Associates (2006) were converted from grain size major mode (phi) to percent silt and clay grain size distribution prior to use in spatial interpolations. A portion (21%) of the SPI results was validated with laboratory analysis results of grain size distribution to verify accuracy of conversion. The mean thickness of dredged material was used unmodified from the SPI survey results, except that ‘trace’ dredged material thickness was interpreted as ≤0.5 cm. Physical analysis results from 12 stations sampled in 2008 and presented in EPA (2009) were used to supplement the SPI dataset. Recent water temperature data recorded in October 2007 using a conductivity- temperature-depth (CTD) profiler by EPA (2009) were used to verify that this environmental variable remained suitable for golden tilefish.

The ArcMap extension Spatial Analyst (https://www.esri.com/en-us/store/extensions/arcgis-spatial-analyst) was used to perform spatial interpolation using ordinary kriging and inverse distance weighting (IDW) on the above-mentioned sediment data. Ordinary kriging uses weighted linear combinations of data having a mean prediction error equal to 0 and strives to minimize the variance of errors. For this reason, ordinary kriging is considered a member of the best- linear-unbiased-predictors (BLUP) category of interpolation methods. IDW interpolation assigns a weight to each point as an inverse proportion to the distance between the nearest points (Bolstad 2008). IDW is an exact interpolation method where interpolated values are equal to known values at each sampled point (Bolstad 2008).

Kriging was conducted using no transformation, a 2nd order polynomial and 100% global trend, a nugget of 0.43, and 12 lags with a lag size of 0.003525. Prior to IDW, the data were investigated using histograms, normal quantile- quantile plots, trend analysis, Voronoi maps, and semivariogram/covariance clouds. The data were not transformed and compared well with standard normal distribution, and the distribution trend was removed using the 2nd order polynomial. The root-mean-square prediction error for kriging was 8.805, and it was not possible to reduce this prediction error using the existing dataset. The lowest IDW prediction error (root-mean-square of 14.62) was obtained by reducing the power value to 1.

Results of interpolations, along with sediment composition and water temperature data, were then compared with the known environmental parameters preferred by golden tilefish as determined in the primary literature (e.g., Able et al. 1993, Able 2002, Dooley 2002).

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RESULTS Post-disposal Effects Kriging Results Results of the kriging analysis predicted percent silt and clay over 11.7 km2 (3.4 nmi2) (67% of the study area), including the Miami ODMDS. Significant (>30%) silt and clay composition occurred over the majority of the 11.7-km2 area covered (Figure 4). About 1.0 km2 (0.3 nmi2) within the Miami ODMDS and extending slightly north had ≤30% silt and clay composition. This area may be less suitable for golden tilefish habitat based solely on kriging results.

IDW Results Results of the IDW interpolation analysis showed somewhat similar results as in kriging, although predicted percent silt and clay concentrations did not fall below 29.7% using this interpolation method (Figure 5). The root-mean-square prediction error was 14.62, which is greater than that of kriging (8.805). The lowest percent silt/clay concentrations (29.7% to 42.1%) were predicted within an oblong area of 1.4 km2 (0.4 nmi2) within the Miami ODMDS and extending just north of it. The remaining 10.3 km2 (3.0 nmi2) area within the analysis appeared to be well suited for golden tilefish based on the high (>37%) silt and clay concentrations predicted by IDW analysis.

Mapping percent gravel and depth of dredged material revealed that areas within the Miami ODMDS and just north of it had substrates not well suited for golden tilefish habitation (Figure 5). Percent gravel ranged up to 17.5% using 12 sediment samples taken in August 2008. Temperature data recorded in October 2007 indicate that most or all of the study area was near or within the narrow bottom temperature range (8.6° to 15.4°C; Able et al. 1993) preferred by golden tilefish.

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Figure 4. Results of ordinary kriging analysis using results of 58 SPI station observations from October 2006 and physical analysis results of 12 sediment samples collected August 2008. Results indicate that, despite decades of dredged material disposal activities, much of the study area continues to have high silt and (or) clay content necessary for golden tilefish (Lopholatilus chamaeleonticeps) burrow construction and maintenance. Sources: SPI results in Germano & Associates (2006) converted from phi; sediment physical and water temperature data from EPA (2009); Miami ODMDS coordinates from EPA (2001).

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Figure 5. Results of IDW analysis using results of 58 SPI station observations from October 2006 and physical analysis results of 12 sediment samples collected August 2008. Results indicate that, despite decades of dredged material disposal activities, much of the study area continues to have high silt and (or) clay content necessary for golden tilefish (Lopholatilus chamaeleonticeps) burrow construction and maintenance. Sources: SPI results in Germano & Associates (2006) converted from phi; sediment physical and water temperature data from EPA (2009); Miami ODMDS coordinates from EPA (2001).

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CONCLUSIONS AND DISCUSSION Overall, these results suggest that most of the 17.5-km2 (5.1-nmi2) study area remains suitable for golden tilefish as it appears to meet the sediment, temperature, and depth requirements for the species. A relatively small area within the Miami ODMDS and directly north of it may no longer be suitable for golden tilefish due to the disposal of coarse sand, gravel, and limestone rubble dredged from nearby Miami Harbor. Areas now containing rock and gravel may now be more attractive to reef species of management interest, such as snowy grouper, misty grouper (Hyporthodus mystacinus), red grouper (Epinephelus morio), warsaw grouper (Hyporthodus nigritus), and silk snapper.

This study has significant limitations at predicting golden tilefish habitat suitability. Sediment samples and SPI records represent only surficial sediments (≤14 cm depth), yet golden tilefish burrows extend meters into the substrate. The effects of nourishment of surficial sediments on golden tilefish have not previously been studied, and thus it is difficult to predict the effects of dredged material disposal on this species. Burrow creation or burrow maintenance, or both, may be affected by dumped limestone, gravel, and sand if the non-native sediment reaches a critical thickness. However, this hypothesis has not been tested and no critical thickness has been identified to-date.

The SPI records and sediment samples were clustered around the Miami ODMDS, while the remaining study area had little or no sample results available. This reduced the interpolations to 67% (11.7 km2 [3.4 nmi2]) of the study area. The number of observations used in the interpolations (n = 70) is not considered robust according to Webster and Oliver (2007), and the relatively low number of samples likely affected the results. Additionally, the kriging and IDW prediction errors were significant due to the limited sample size. These prediction errors could not be reduced without expensive and time-intensive surveys of the area to obtain further observations. Because dredged material was unlikely to be deposited northward of the 11.7-km2 predicted area, the remaining 5.8-km2 (1.7 nmi2) portion of the study area probably remains unaffected by anthropogenic impacts and is suitable for tilefish habitation.

Results of spatial interpolation indicated that significant (>30%) silt and clay composition still occurs over most of the area in and around the Miami ODMDS. About 1.0 km2 (0.3 nmi2) within the Miami ODMDS and extending slightly north may be less suitable for tilefish habitat. The remaining 16.5-km2 (4.8-nmi2) portion (94%) of the study area appears to remain suitable for tilefish habitat based on the results of this study.

The author suggests that further studies be performed to better determine the impacts of dredged material disposal on federally managed species such as golden tilefish. It may be necessary to use capture gear such as rod and reel, bottom longline, or fish traps to confirm the presence of this species. Alternatively, a new ROV video survey could be performed to document tilefish burrows and other signs of managed species.

Management Implications Tilefish habitat may not be strongly affected by dredged material disposal based on this study, and there may not be significant effects to the tilefish fishery. Dredging stakeholders are not likely to make major changes to disposal methods for economic and logistical reasons. Local fishery stakeholders may not experience strong changes to the fishery if these sites continue to provide habitat for tilefish stocks.

Golden tilefish have not been successfully aquacultured, and this important means of enhancement (as discussed in Lorenzen 2008) appears impractical for this deepwater species. For this reason, habitat for wild stocks of tilefish is particularly important. Today, the species is targeted in Florida by commercial fishers mainly using bottom longline gear (Shephard 1998) and occasionally is targeted by recreational anglers using electric or conventional reels (Wickstrom 2015). Although tilefish grounds are many miles offshore in most of the United States, anglers can target tilefish off Miami and the Florida Keys as little as 5.6 km (3 nmi) offshore due to the proximity of the continental slope in these areas. Golden tilefish occur off Miami in large enough numbers to be targeted in commercial and recreational fisheries (Freeman and Walford 1976, Wickstrom 2015), and charter boats are available that specialize in tilefish fishing (Wickstrom 2015). However, most of the tilefish harvested in Florida is by commercial fishers (FWC 2018), although tilefish represent only a portion of their catch and income given that these fishers use a multi-species fishing permit that includes various snapper and grouper species in addition to tilefish (NOAA Fisheries Southeast Regional Office 2018).

In addition to the Miami ODMDS, other ODMDSs are located along the upper continental slope in areas with probable tilefish habitat, such as those off Fort Lauderdale and Key West. The Port Everglades Harbor ODMDS off Fort Lauderdale appears well suited for tilefish based on water depth, temperature, and substrate composition as established

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in ANAMAR (2012), and a young-of-year golden tilefish was captured in a trawl conducted near this site in May 2011 (Figure 6). In addition to the Miami and Port Everglades Harbor disposal sites, the 3.4-km2 (1-nmi2) Key West Harbor ODMDS is located along the upper slope of the Straits of Florida and may also be within tilefish habitat. All these disposal sites are co-managed by USACE and EPA according to site-specific Site Management and Monitoring Plans (SMMPs), which focus largely on managing levels of environmental contaminants and generally lack taxon-specific management goals (although minimizing effects to fisheries is a concern). Faunal changes at U.S. ODMDSs are monitored at regular intervals, but monitoring studies largely involve benthic infaunal surveys (epifaunal studies are not regularly undertaken).

Figure 6. A 55-mm standard length post-settlement golden tilefish ((Lopholatilus chamaeleonticeps) captured by trawl near the Port Everglades ODMDS in May 2011. Photo courtesy, A. Bemis of Florida Museum of Natural History, University of Florida, Gainesville, FL.

Spatial interpolation is a low-cost method of predicting the habitat suitability of ODMDSs for fish stocks of management interest, as demonstrated here. Although golden tilefish represent an unusual life history strategy, using burrows in soft sediments as structure instead of using existing structure as in many reef-oriented fishes, this species nonetheless represents a valuable resource in Florida and elsewhere along the U.S. eastern seaboard. The use of spatial interpolation methods combined with existing sediment data allows for a cost-effective alternative to resource- intensive sidescan sonar surveys or sediment sampling and analysis surveys.

Commercial landings of golden tilefish in Florida averaged 296,116 kg annually over the last decade, with an average annual wholesale value of over $1.7 million (Florida Fish and Wildlife Conservation Commission [FWC] 2018) (Table 2). Recreational landings of golden tilefish in Florida averaged 4,642 fish landed annually over this same period (NOAA Fisheries Statistics Division 2018) (Table 3). Thus, habitat management efforts appear be justified for this economically important species.

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Table 2. Commercial landings of golden tilefish (Lopholatilus chamaeleonticeps) in Florida during the last decade (2008–2017). 1 1 Florida Atlantic Coast Landings Florida Gulf Coast Landings Overall Year (kg) (lb) Value 2 (kg) (lb) Value 2 Value 2008 158,241 348,862 $812,745 116,013 255,764 $404,289 $1,217,034 2009 154,620 340,878 $753,736 166,613 367,320 $512,516 $1,266,252 2010 171,187 377,403 $1,014,814 49,856 109,914 $237,904 $1,252,718 2011 174,933 385,661 $1,033,914 63,103 139,118 $310,703 $1,344,617 2012 248,610 548,092 $1,440,691 83,596 184,298 $439,716 $1,880,407 2013 224,835 495,677 $1,408,654 86,984 191,768 $493,538 $1,902,192 2014 290,278 639,955 $1,834,894 107,502 237,002 $608,748 $2,443,642 2015 207,100 456,577 $1,526,649 116,579 257,013 $694,803 $2,221,452 2016 199,630 440,110 $1,524,572 66,905 147,501 $398,995 $1,923,567 2017 194,596 429,012 $1,637,912 64,610 142,440 $379,603 $2,017,515 Mean 202,403 446,223 $1,298,858 92,176 203,214 $448,082 $1,746,940 (annual) 1 Landings are given in whole weight (lb) and converted to kg. 2 Value calculated from average wholesale value per pound of whole weight at time of sale. Source: FWC (2018) (https://public.myfwc.com/FWRI/PFDM/ReportCreator.aspx)

Table 3. Recreational landings of golden tilefish (Lopholatilus chamaeleonticeps) in Florida during the last decade (2008–2017). Number of Fish Harvested off Florida Number of Fish Harvested off Year Atlantic Coast 1 Florida Gulf Coast 1 State-wide 2008 0 38 38 2009 7,741 0 7,741 2010 2,216 81 2,297 2011 4,876 0 4,876 2012 2,940 257 3,197 2013 3,135 0 3,135 2014 732 2,999 3,731 2015 3,516 2,506 6,022 2016 9,521 4,474 13,995 2017 1,216 168 1,384 Mean (annual) 3,988 1,503 4,642 1 Harvested fish are those back to the dock plus those used for bait, released dead, or filleted. Source: NOAA Fisheries Statistics Division (2018) (https://www.st.nmfs.noaa.gov/SASStoredProcess/do)

I recommend that habitat be evaluated in and around ODMDSs within the preferred depth range and substrate composition of golden tilefish to begin to understand the relationship between material placement and tilefish habitation. Further investigative methods to employ include sidescan sonar surveys of burrows, ROV transects, and fishing surveys to ascertain the current status of tilefish in these areas. I further recommend that fisheries managers and agencies tasked with management of offshore disposal sites (i.e., EPA, USACE) exchange information and recommendations to increase awareness of potential impacts to fisheries and to establish strategies to avoid or ameliorate such impacts. Each SMMP should identify fisheries important to the area and suggest ways of avoiding impacts, as habitat impacts are particularly difficult to correct. In this way, fisheries and habitat management can work in an integrative manner to the benefit of fisheries, marine ecosystems, and the seafood-based economy while ensuring

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the continued maintenance and improvements to coastal navigation necessary to satisfy the modern global marketplace.

REFERENCES Able, K.W. 2002. Tilefishes. Family Malacanthidae. Pp. 397–400 In: B.B. Collette and G. Klein-MacPhee (eds.) Bigelow and Schroeder’s Fishes of the Gulf of Maine. Smithsonian Institute Press, Washington, D.C.

Able, K.W., C.B. Grimes, R.S. Jones, and D.C. Twichell. 1993. Temporal and spatial variation in habitat characteristics of tilefish (Lopholatilus chamaeleonticeps) off the east coast of Florida. Bulletin of Marine Science 53(3)1013–1026.

Able, K., D. Twitchell, C. Grimes, and R. Jones. 1987. Tilefishes of the genus Caulolatilus construct burrows in the sea floor. Bulletin of Marine Science 40:1–10.

Arlinghaus, R., T. Mehner, and I.G. Cowx. 2002. Reconciling traditional inland fisheries management and sustainability in industrialized countries, with emphasis on Europe. Fish and Fisheries 3:261–316.

ANAMAR. 2012. Final Report, Site Designation Study for the Port Everglades Harbor Ocean Dredged Material Disposal Site Expansion: May 2011 Survey Results. Submitted to U.S. Army Corps of Engineers, Jacksonville District, Jacksonville, FL.

ANAMAR and HBOI. 2010. Final Report, Tilefish (Malacanthidae) Habitat Characterization in and around the Miami, Florida, Ocean Dredged Material Disposal Site Using 1986 Videographic Data. Submitted to U.S. Army Corps of Engineers, Jacksonville District, Jacksonville, FL.

Bolstad, P. 2008. GIS Fundamentals: A First Text on Geographic Information Systems. Eider Press, White Bear Lake, MN.

Conservation Consultants. 1985. Appendix A. Environmental Survey in the Vicinity of an Ocean Dredged Material Disposal Site, Miami Harbor, Florida. Submitted to Department of the Army Corps of Engineers, Jacksonville, FL.

Conservation Consultants. 1986. Appendix A. Supplemental Information: Video Survey of Dredged Material Disposal Sites Located off Ft. Pierce Harbor and Miami Harbor, Florida. Submitted to Department of the Army Corps of Engineers, Jacksonville, FL.

Cooper, A.B. 2006. A Guide to Fisheries Stock Assessment, from Data to Recommendations. NH Sea Grant Program, Kingham Farm, University of New Hampshire, Durham, NH.

Crowe, S.E., P.T. Gayes, R.F. Viso, D.C. Bergquist, and P.C. Jutte. 2010. Impact of the Charleston Ocean Dredged Material Disposal Site on nearby hard bottom reef habitats. Marine Pollution Bulletin 60:679–691.

Dooley, J.K. 2002. Branchiostegidae, tilefishes (sand tilefishes). Pp. 1395–1411 In: K.E. Carpenter (ed.) The Living Marine Resources of the Western Central Atlantic. Volume 3, Bony Fishes Part 2 (Opistognathidae to Molidae), Sea Turtles and Marine Mammals. Food and Agriculture Organization of the United Nations, Rome, Italy.

EPA. 2001. Sediment Survey: Ocean Dredged Material Disposal Site, Miami, Florida. EPA, Region 4, Water Management Division and Science and Ecosystem Support Division, Athens, GA.

EPA. 2009. Miami, Florida Ocean Dredged Material Disposal Site (ODMDS) and South Florida Reference Evaluation (SFLARE). October 4-October 11, 2007. Final Report, Revision 1: April 3, 2009. EPA Science and Ecosystem Support Division, Athens, GA.

EPA. 2018. Ocean Disposal Map [online resource]. Accessed 03/05/18 at https://www.epa.gov/ocean- dumping/ocean-disposal-map.

EPA and USACE. 2008. Miami Ocean Dredged Material Disposal Site, Site Management and Monitoring Plan. EPA, Region 4, Atlantic GA and USACE, Jacksonville District, Jacksonville, FL.

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FWC. 2018. Commercial Fisheries Landings Summaries [online resource]. Accessed 02/28/18 at https://public.myfwc.com/FWRI/PFDM/ReportCreator.aspx.

Freeman, B.L. and L.A. Walford. 1976. Angler’s Guide to the United States Atlantic Coast. Fish, Fishing Grounds & Fishing Facilities. Section VIII St. Lucie Inlet, Florida to the Dry Tortugas. National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Seattle, WA.

Germano & Associates,. 2006. Rapid Seafloor Reconnaissance and Assessment of Southeast Florida Ocean Dredged Material Disposal Sites Utilizing Sediment Profile Imaging. May 2006 Post-disposal SPI Mapping at the Miami ODMDS. Submitted to U.S. Environmental Protection Agency, Region 4, Atlanta, GA.

Grimes, C.B., K.W. Able, and R.S. Jones. 1986. Tilefish, Lopholatilus chamaeleonticeps, habitat, behavior and community structure in Mid-Atlantic and southern New England waters. Environmental Biology of Fishes 15(4):273– 292.

Kamlet, K.S. 1983. Dredged-material ocean dumping: Perspectives on legal and environmental impacts. Pp. 29–70. In: D.R. Kester, B.H. Detchum, I.W. Duedall, and P.K. Park (eds.) Wastes in the Ocean, Volume 2: Dredged Material Disposal in the Ocean. John Wiley & Sons, Inc., New York, NY.

Livingston, R.J. 1990. Inshore marine habitats. Pp. 549–573. In: R.L. Myers and J.J. Ewel (eds.) Ecosystems of Florida. University of Central Florida Press, Orlando, FL.

Lorenzen, K. 2008. Understanding and managing enhancement fisheries systems. Reviews in Fisheries Science 16(1):10–23.

Marine Protection, Research, and Sanctuaries Act of 1972, §103, 33 U.S.C. §1413 (2011).

NOAA Fisheries Statistics Division. 2018. MRIP National Query [online resource]. Accessed 02/28/18 at https://www.st.nmfs.noaa.gov/SASStoredProcess/do?.

NOAA Fisheries Southeast Regional Office. 2018. SERO Permits Office [online resource]. Accessed 03/01/18 at http://sero.nmfs.noaa.gov/operations_management_information_services/constituency_services_branch/permits/per mits_%20details/index.html.

Seitz, J.C. and G.R. Poulakis. 2006. Anthropogenic effects on the smalltooth sawfish (Pristis pectinata) in the United States. Marine Pollution Bulletin 52:1533–1540.

Shepherd, G.R. 1998. Tilefish. Pp. 102-103 In: S.H. Clark, (ed.) Status of Fishery Resources off the Northeastern United States for 1998. NOAA Technical Memorandum NMFS-NE-115, NOAA, NMFS, Seattle, WA.

USACE. 2015. Engineering and Design, Dredging and Dredged Material Management. Manual No. 1110-2-5025, USACE, Washington, D.C.

USACE 2018. Ocean Disposal Database [online resource]. Accessed 02/22/18 at: https://odd.el.erdc.dren.mil/ODMDSSearch.cfm.

Webster, R. and M.A. Oliver. 2007. Geostatistics for the Environmental Scientist. John Wiley & Sons Ltd, West Sussex, England.

Wickstrom, B. 2015. Targeting golden tilefish [online resource]. Florida Sportsman accessed 03/01/18 at http://www.floridasportsman.com/2015/11/12/targeting-golden-tilefish/.

CITATION Seitz, J.C. 2018. Spatial interpolation as a tool to assess the effects of ocean disposal on economically important species: golden tilefish habitat at Miami ODMDS as a case study. Proceedings of the Western Dredging Association Dredging Summit & Expo ’18, Norfolk, VA, USA, June 25–28, 2018.

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ACKNOWLEDGEMENTS I thank the following people for their help. Christopher McArthur (EPA, Region 4) provided encouragement and EPA documents, Sabine Grunwald (University of Florida [UF]) provided excellent advice on spatial analysis, and Kai Lorenzen and Edward Camp (UF) provided advice on fisheries management perspectives and on the construction of an integrated framework. Connie Steen (ANAMAR) provided editorial review comments that improved this manuscript. Jennifer Seitz and ANAMAR, especially Nadia Lombardero, provided support and encouragement for this project since its inception.

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