08-Permit_Attachment_SeagrassandCoral_ SurveyandMitigation_Plans_NPS_05-2020.pdf

NPS CHRI 217021 Replace Wharf Bulkhead

Draft Final Seagrass and Coral Surveys and Mitigation Plan (Revision 2)

Christiansted National Historic Site, Christiansted Harbor, St. Croix, U.S. Virgin Islands

Contract Number 47QRAA18D00H0

Order No. 140P2019F0249

APRIL 2020

Prepared for:

National Park Service, Christiansted National Historic Site

Prepared by:

Dial Cordy and Associates, Inc. February 2019

Revised by:

Tetra Tech, Inc. April 2020

CHRI 217021 Replace Wharf Bulkhead Seagrass/Coral Surveys & Mitigation Plan ii

Table of Contents

CHAPTER 1. CORAL RESOURCES LOCATED ON THE CHRISTIANSTED NATIONAL HISTORIC SITE WHARF

BULKHEAD

1.1 Project Description

1.2 Introduction

1.3 Methods

1.4 Results

CHAPTER 2. BENTHIC RESOURCES IN MARINE BOTTOMLANDS AT THE CHRISTIANSTED NATIONAL

HISTORIC SITE WHARF BULKHEAD

2.1 Introduction

2.2 Methods

2.3 Results

2.4 Project Concerns and Mitigation

CHAPTER 3. CORAL MITIGATION PLAN

3.1. Recipient Site Selection

3.2. Coral Handling and Decontamination Procedures

3.3. Coral Removal and Relocation Protocol

3.4. Coral Reattachment Protocol

3.5. Mooring Installation

3.6. Staging Area

3.7. Inclement Weather Operations

3.8. Documentation

3.9. Coral Relocation Monitoring

3.10. Performance Standards

LITERATURE CITED

iii

List of Tables

Table 1. Scleractinian coral species observed on the bulkhead

Table 2. Size distribution and abundance of coral species observed on bulkhead

Table 3. Summary of line-intercept transect data

Table 4. Summary of observed seagrass species and median percent cover

Table 5. Coral species noted in bottomlands

Table 6. Size distribution and abundance by coral species to be relocated

Table 7. Recipient site coordinates (NAD83, UTM 20N, Meters)

List of Figures

Figure 1. Christiansted National Historic Site Wharf Bulkhead (Source: Dial Cordy, 2019)

Figure 2. The three ESA-listed coral species observed during bulkhead surveys: Orbicella faveolata, Orbicella annularis, and Orbicella franksi (lumped as Orbicell-a annularis species complex) (Source: Dial Cordy, 2019)

Figure 3. Location of all 13 photomosaic sections on Christiansted bulkhead (Source: Dial Cordy, 2019)

Figure 4. Photomosaic of bulkhead wall showing circled Orbicella spp. with scale bars (approximately 50-cm in length) (Source: Dial Cordy, 2019)

Figure 5. Close-up still photograph of Orbicella spp. colony highlighted on photomosaic panel #5 from previous figure (Source: Dial Cordy, 2019)

Figure 6. Turtle grass (Thalassia testudinum) admixed with rubble substrate at the eastern end of the survey area (Source: Dial Cordy, 2019)

Figure 7. Site map depicting the 15 transect locations used to survey the benthic resources present in the bottomlands adjacent to the bulkhead of the Christiansted National Historic Site, Christiansted, St. Croix, U.S.V.I. (Source: Dial Cordy, 2019)

Figure 8. Benthic habitat characterization along 15 belt transects within survey boundary (Source: Dial Cordy, 2019)

Figure 9. (A) Exotic invasive seagrass exotic paddle grass (Halophila stipulacea), (B) turtle grass (Thalassia testudinum), (C) paddle grass (Halophila decipiens), (D) Penicillus capitatus, (E) Halimeda incrassate, and (F) Udotea flabellum (Source: Dial Cordy, 2019)

Figure 10. Interpolated cover of submerged aquatic vegetation within the survey boundary (Source: Dial Cordy, 2019)

Figure 11. Seagrass bed dominated by the exotic invasive exotic paddle grass (Halophila stipulacea).

This invasive seagrass species was common throughout the western portion of project site.

(Source: Dial Cordy, 2019)

Figure 12. Seagrass bed dominated by turtle grass (Thalassia testudinum) in the eastern portion of the project area (Source: Dial Cordy, 2019) iv

Figure 13. Mixed seagrass community dominated by turtle grass (Thalassia testudinum) with understory of invasive exotic paddle grass (Halophila stipulacea) (Source: Dial Cordy, 2019)

Figure 14. Large areas of sand covered with the calcareous green algae (Penicillus capitatus) (Source:

Dial Cordy, 2019)

Figure 15. Drift algae composed mainly of the brown algae (Dictyota spp.) was common throughout the surveyed area (Source: Dial Cordy, 2019)

Figure 16. Benthic invertebrates observed in the bottomlands fronting the bulkhead: (A) volcano-shaped sediment structures built by the burrowing of the ghost shrimp (Callianassa sp.), (B) bearded fireworm (Hermodice carunculate), (C) giant anemone (Condylactis gigantean),

(D) giant hermit crab (Petrochirus diogenes), (E) variegated feather duster worm, (Bispira variegate), (F) variegated sea urchin, (Lytechinus variegatus) (Source: Dial Cordy, 2019)17

Figure 17. Four coral species found in the bottomland habitat fronting the bulkhead: (A) mustard hill coral (Porites astreoides), (B) branching finger coral (Porites porites), (C) massive starlet coral (Siderastrea siderea), (D) blushing star coral (Stephanocoenia intersepta) (Source: Dial Cordy, 2019)

Figure 18. Isolated colony of Symmetrical Brain Coral (Pseudodiploria strigosa) found on rubble bottom in easternmost portion of the project area (Source: Dial Cordy, 2019)

Figure 19. Isolated colony of the ESA-listed coral Lobed Star Coral (Orbicella annularis) species complex found on cement structure within the project boundary (Source: Dial Cordy, 2019)

Figure 20. Corals found scattered on hard debris throughout project site (Source: Dial Cordy, 2019) 19

Figure 21. Tires and other debris were found scattered throughout the project site (Source: Dial Cordy, 2019)

Figure 22. Avoidance and impact minimization areas within project area (Source: Dial Cordy, 2019) 22

Figure 23. Sea surface temperatures for the USVI from 01 Jan 2001 to 30 March 2020 (Source: NOAA, 2020)

Figure 24. Green boxes present the extent of the delineated recipient sites for reattachment of relocated corals from the donor site (CHRI bulkhead) and the the bottamlands adjacent to the bulkhead (Source:Tetra Tech, 2020)

Figure 25. (A) Scientific diver carefully removing coral colony for relocation, (B) large Siderastrea colony being carefully removed from wall, (C) diver carrying colony following removal, (D) plastic bin used to cache and transport corals after removal, (E) colony of (Porites astreoides) reattached on natural hardbottom surface (grey coloration is Portland cement), (F) diver monitoring the status of relocated corals (Source: Dial Cordy, 2019) v

Appendices

Appendix A - 13 Individual Photo Mosaics of Bulkhead Wall Going from East to West. Positions of Individual Colonies of the ESA-Listed Coral Species Lobed Star Coral (Orbicella annularis) are highlighted.

(Attached as JPG Images)

Appendix B - Close-up Photographs of 26 Identified Lobed Star Coral (Orbicella annularis) colonies with their Corresponding Identification Tag.

Appendix C - Coral IDs from Photos taken on Christiansted Wharf Bulkhead

Appendix D – Coral Relocation Monitoring Data Sheet

Appendix E – NPS doc

CHAPTER 1. CORAL RESOURCES LOCATED ON THE CHRISTIANSTED NATIONAL 1

HISTORIC SITE WHARF BULKHEAD 2

1.1 Project Description 3

The National Park Service (NPS) will be constructing a new bulkhead (700 linear feet (ft) in length) 4 immediately seaward of the existing wharf bulkhead to provide continued protection to the Christiansted 5

National Historic Site (NHS) landscape and associated historic buildings. This new bulkhead would enclose 6 the existing bulkhead and will reduce the threats of sea level rise impacts to the historic site in addition 7 to restoring wharf access, appropriate use, and functionality. The design is expected to have a 40-year life 8 cycle and be capable of allowing overtopping events. Christiansted Harbor is a tropical marine 9 environment characterized by abundant marine life, seagrass habitat, and coral reef habitat along the 10 outer harbor. The existing bulkhead and surrounding area are replete with a diverse benthic community 11 that includes multiple species of scleractinian corals, seagrasses, urchins, reef fish, and other 12 invertebrates. Coral, benthic, and seagrass surveys were performed in order to document and quantify 13 the scleractinian coral resources located on the wharf bulkhead and the benthic resources present in the 14 marine bottomlands. The results of these underwater surveys will be used to reduce and/or prevent any 15 construction-related impacts to these marine resources by: 1) removing and relocating scleractinian corals 16 on the existing bulkhead prior to construction, 2) monitoring the recipient sites for continued protection 17 of coral habitat, and 3.) identifying resource protection areas (seagrass habitat) in order to protect those 18 existing benthic communities, if necessary. 19

1.2 Introduction 20

From September 19-20, 2018 scientific divers performed in-situ coral surveys along the bulkhead fronting 21 the Christiansted National Historic Site Wharf (see Figure 1) (Dial Cordy and Associates 2017). In addition 22 to the in-situ surveys, during September 19-21, 2018, Dial Cordy and Associates, Inc (DCA) video-graphed 23 the entire portion of the submerged bulkhead for development (post processing) of a photo-mosaic of 24 the bulkhead panels in order to map individual colony locations on the bulkhead to assist with the 25 proposed coral relocation effort. Additionally, a recipient site survey was completed on January 28 and 26

29, 2020 to locate suitable habitat for relocation of the stony corals located on the bulkhead structure 27

(Tetra Tech 2020). Detailed results of the recipient sites and the selection process are presented in the 28

Coral Relocation and Monitoring Services – Coral Recipient Site Assessment Report (Tetra Tech, 2020). 29

Figure 1. Christiansted National Historic Site Wharf Bulkhead (Source: Dial Cordy, 2019) 2

1.3 Methods 3

DCA divers conducted an in-situ coral survey along the entire 700-ft length of the existing bulkhead. A 50-4 centimeter (cm) scale bar was used to assess coral colony size and an underwater camera was used to 5 collect coral colony photographs. 6

The following specific information was collected: 7

• Species (to the lowest taxonomic rank possible) 8

• Size class (based on maximum dimension: <5cm, 5-10cm, >10-50cm, >50cm) 9

• Total number of coral colonies 10

• Total number of ESA-listed coral colonies 11

• Coral condition (e.g. bleaching or disease indicators) 12

• General description of original colony location and depth 13

• Still photographs of each ESA-listed coral (Figure 2) 14

Figure 2. The three ESA-listed coral species observed during bulkhead surveys: Orbicella faveolata, 16

Orbicella annularis, and Orbicella franksi (lumped as Orbicell-a annularis species complex) (Source: 17

Dial Cordy, 2019) 18

The visual documentation of scleractinian corals along the bulkhead was collected in two formats: 1) 1 close-up still photographs of individual corals and 2) underwater video collection to be used in the creation 2 of a 2-dimensional mosaic of the bulkhead. High-definition video data was collected in a grid pattern 3 across 13 distinct segments of the bulkhead (Figure 3). Video data was post-processed to create a set of 4 still images of each bulkhead segment, which were then compiled into a composite mosaic of the 5 bulkhead segment (Appendix A). The close-up still photographs and mosaic images were compared and 6 the location of each ESA-listed coral species was flagged and numbered on each mosaic, if present (Figures 7

4 and 5). These photomosaic images may also be used to quantify size and abundance of scleractinian 8 corals as well as species verification when combined with additional close-up field photographs of corals 9

(see Figures 3 and 4). We have performed this analysis for the ESA-listed Lobed Star Coral (Orbicella 10 annularis) species complex (see Appendix B). 11

CHRI 217021 Replace Wharf Bulkhead Seagrass/Coral Surveys & Mitigation Plan (Tt Rev. 01)

Figure 3. Location of all 13 photomosaic sections on Christiansted bulkhead (Source: Dial Cordy, 2019) 2

Figure 4. Photomosaic of bulkhead wall showing circled Orbicella spp. with scale bars (approximately 2

50-cm in length) (Source: Dial Cordy, 2019) 3

Figure 5. Close-up still photograph of Orbicella spp. colony highlighted on photomosaic panel #5 from 5 previous figure (Source: Dial Cordy, 2019) 6

1.4 Results 1

The in-situ bulkhead survey resulted in the identification of 18 scleractinian coral species present on the 2 bulkhead (Table 1). In total, there were 498 corals >5 cm observed on the bulkhead (Table 2). Of these, 3

84 coral colonies were between 5-10 cm, another 373 colonies were between >10-50 cm, and 41 colonies 4 greater than 50 cm in their longest dimension. All observed colonies were counted, measured and 5 photographed. In addition, we noted dozens of coral recruits including Club Finger Coral (Porites porites) 6 and numerous small colonies of Lesser Starlet Coral (Siderastrea radians) and Golf Ball Coral (Favia 7 fragum) all smaller than 5 cm (see Table 2). Because of their small size, often cryptic nature, and high 8 mortality, corals <5 cm were noted but not tallied in this survey. Symmetrical Brain Coral (Pseudodiploria 9 strigosa) and Knobby Brain Coral (Pseudodiploria clivosa) were the most common corals present, 10 accounting for more than 50% of all corals observed. As an aid, we have included a photographic ID for 11 the 18 species found on the bulkhead (Appendix C). The only ESA Listed coral species found on the 12 bulkhead included the Lobed Star Coral (Orbicella annularis) (OANN) species complex. 26 of the 498 corals 13

>5 cm were OANN species complex (5.2%). 14

Table 1. Scleractinian coral species observed on the bulkhead 15

Species Observed AGGRA Abbreviation Common Name

Porites astreoides PAST Mustard Hill Coral

Porites porites PPOR Club Finger Coral

Siderastrea siderea SSID Massive Starlet Coral

Siderastrea radians SRAD Lesser Starlet Coral

Favia fragum FFRA Golf Ball Coral

Eusmilia fastigiata EFAS Flower Coral

Stephanocoenia intersepta SINT Blushing Star Coral

Dichocoenia stokesi DSTO Elliptical Star Coral

Colpophyllia natans CNAT Boulder Brain Coral

Orbicella annularis (species complex)* OANN Lobed Star Coral

Pseudodiploria strigosa PSTR Symmetrical Brain Coral

Pseudodiploria clivosa PCLI Knobby Brain Coral

Meandrina meandrites MMEA Maze Coral

Agaricia agaricites AAGA Lettuce Coral

Agaricia lamarcki ALAM Whitestar Sheet Coral

Manicina areolata MAER Rose Coral

Table 2. Size distribution and abundance of coral species observed on bulkhead 1

Species Common Name <5 cm 5– 10 cm >10– 50 cm >50 cm

PAST Mustard Hill Coral numerous 10 63 2

PPOR Club Finger Coral numerous 24 50 -

SSID Massive Starlet Coral few 5 20 2

SRAD Lesser Starlet Coral numerous 9 - -

FFRA Golf Ball Coral numerous 3 - -

EFAS Flower Coral - - 1 -

SINT Blushing Star Coral - 1 - -

DSTO Elliptical Star Coral 1 4 - -

CNAT Boulder Brain Coral - 3 10 5

OANN (species complex complex*)

Lobed, Boulder Star, Mountainous Star Coral

- 19 7

PSTR Symmetrical Brain Coral 4 20 126 11

PCLI Knobby Brain Coral 2 - 84 13

MMEA Maze Coral - 3 - -

AAGA Lettuce Coral few 1 - -

ALAM Whitestar Sheet Coral - - - 1

MAER Rose Coral 1

Totals Dozens 84 373 41

*The ESA-Listed Orbicella species are lumped into OANN species complex category. The Lobed Star Coral (Orbicella 2 annularis) species complex is comprised of three closely related species, Lobed Star Coral (O. annularis), Boulder 3 Star Coral (O. franksi), and Mountainous Star Coral (O. faveolata). Outward colony morphology is generally used to 4 differentiate species in the field. Field identification, however, is often difficult when colonies are small or 5 encrusting (as in the case of the corals growing on the bulkhead). It is for this reason we have binned the Orbicella 6 together. 7

CHAPTER 2. BENTHIC RESOURCES IN MARINE BOTTOMLANDS AT THE 1

CHRISTIANSTED NATIONAL HISTORIC SITE WHARF BULKHEAD 2

2.1 Introduction 3

On September 18-19, 2018 scientific divers of Dial Cordy and Associates, Inc. (DCA) performed benthic 4 community resource surveys of bottomlands, which refers to the benthic habitat located directly in front 5 of the Christiansted National Historic Site (NHS) bulkhead. The survey area encompassed approximately 6

2.6 acres of bottomlands. These benthic surveys documented submerged aquatic vegetation (SAV), 7 including various seagrass species and macroalgae. Scleractinian corals, other marine invertebrates, and 8 substrate characteristics were also noted when observed. 9

2.2 Methods 10

DCA used an integrated quantitative and qualitative in-situ survey protocol to accomplish the mapping of 11 seagrass species and other associated benthic resources (ESA-listed corals) fronting the Christiansted NHS 12 bulkhead. 13

A total of 15 transects were surveyed throughout the bottomlands. Transects were all 200-ft in length 14 and spaced at intervals of approximately 50-ft along the wall (Figure 7). The heading was established 15 during the first transect, which ran perpendicular to the bulkhead. This same heading was used for all 16 subsequent transects with the exception of transect 6, which had to be altered slightly north due to the 17 orientation of the bulkhead that obstructed the desired heading. 18

Line-intercept data was collected along a 2-meter (m) belt transect along each side of the 200-ft transect 19

(4-m belt per transect). Each belt transect encompassed approximately 2,600 sq. ft. of area for a total of 20

39,000 sq. ft. surveyed within the bottomlands. Line-intercept data noted substrate type and the presence 21 or absence of SAV or other benthic resources (Figure 6). When seagrass was observed, quantitative data 22 were collected in 0.25-m2 quadrats at 10-ft intervals for as long as seagrass was present. Within each 23 quadrat, a Braun-Blanquet (BB) score was assigned for all observed seagrass species, which was used to 24 assess the median percent cover of observed seagrasses. These line-intercept and quadrat data were 25 used to generate detailed benthic habitat maps using ArcGIS computer software within the survey area 26 to map the presence and type of benthic resources and substrate types within the survey area adjacent 27 to the Christansted NHS bulkhead (Figures 8 and 10). 28

Figure 6. Turtle grass (Thalassia testudinum) admixed with rubble substrate at the eastern end of the 30 survey area (Source: Dial Cordy, 2019) 31

Figure 7. Site map depicting the 15 transect locations used to survey the benthic resources present in the bottomlands adjacent to the 2 bulkhead of the Christiansted National Historic Site, Christiansted, St. Croix, U.S.V.I. (Source: Dial Cordy, 2019) 3

Figure 8. Benthic habitat characterization along 15 belt transects within survey boundary (Source: Dial Cordy, 2019) 2

2.3 Results 1

Three species of seagrass were identified including turtle grass (Thalassia testudinum), paddle grass 2

(Halophila decipiens), and exotic paddle grass (Halophila stipulacea) within the project area. In addition, 3 three main species of calcareous green attached algae were observed. Observed species included 4

Penicillus capitatus, Halimeda incrassata, and Udotea flabellum (Figure 9). Large areas of seagrass 5 dominated by monospecific beds of the exotic invasive species exotic paddle grass (Halophila stipulacea) 6 were observed throughout the western half of the project site (Figure 10 and 11). An area of turtle grass 7

(Thalassia testudinum) was also found in very shallow water (<6 ft deep) in easternmost portion of the 8 study area (Figure 10 and 12). This area of turtle grass is presently admixed with exotic paddle grass 9

(Figure 13). A summary of the quantitative seagrass data is provided in Tables 3 and 4. 10

Figure 9. (A) Exotic invasive seagrass exotic paddle grass (Halophila stipulacea), (B) turtle grass 13

(Thalassia testudinum), (C) paddle grass (Halophila decipiens), (D) Penicillus capitatus, (E) Halimeda 14 incrassate, and (F) Udotea flabellum (Source: Dial Cordy, 2019) 15

Figure 10. Interpolated cover of submerged aquatic vegetation within the survey boundary (Source: 3

Dial Cordy, 2019) 4

Table 3. Summary of line-intercept transect data 1

Transect Seagrass Species Quads

Surveyed Average of Median Percent Cover

1 Halophila stipulacea 16 34.2

2 Halophila stipulacea 19 27.9

3 Halophila stipulacea 17 25.0

4 Halophila stipulacea 29 35.6

Halophila decipiens 1 2.5

Halophila stipulacea 26 25.3

6 Halophila stipulacea 15 20.0

7 Halophila stipulacea 26 34.6

8 Halophila stipulacea 13 14.2

Halophila stipulacea 9 13.3

Thalassia testudinum 2 7.5

10 Thalassia testudinum 10 13.0

11 Thalassia testudinum 6 12.5

Halophila stipulacea 4 32.5

Thalassia testudinum 10 11.3

Halophila stipulacea 2 26.3

Thalassia testudinum 13 15.6

Halophila stipulacea 5 24.0

Thalassia testudinum 18 17.8

15 Halophila stipulacea 15 44.3

Table 4. Summary of observed seagrass species and median percent cover 3

Site Summary

Seagrass Species Total

Transects Observed

Total Quads Observed Average of Median Percent Cover

Halophila stipulacea 13 196 28.9

Thalassia testudinum 6 59 14.5

Halophila decipiens 1 1 2.5

Site Total 15 256 25.5

Figure 11. Seagrass bed dominated by the exotic invasive exotic paddle grass (Halophila stipulacea). 2

This invasive seagrass species was common throughout the western portion of project site. (Source: 3

Dial Cordy, 2019) 4

Figure 12. Seagrass bed dominated by turtle grass (Thalassia testudinum) in the eastern portion of the 6 project area (Source: Dial Cordy, 2019) 7

Figure 13. Mixed seagrass community dominated by turtle grass (Thalassia testudinum) with 15 understory of invasive exotic paddle grass (Halophila stipulacea) (Source: Dial Cordy, 2019) 16

Large areas of sand covered with the calcareous green algae (Penicillus capitatus) (Figure 14) as well as 17 drift algae comprised mainly of brown algae (Dictyota sp.) are also found throughout the project site 18

(Figure 15). The urchins (lime urchin [Diadema antillarum], variegated sea urchin [Lytechinus variegatus] 19 and white sea urchin [Tripneustes ventricosus]) were also noted in the grassbeds. Hermit crabs were 20 plentiful and we observed one giant hermit crab (Petrochirus diogenes). The variegated feather duster 21 worm (Bispira variegate) is present but not common. Another common feature of both the sand areas 22 and grassbeds were volcano shaped sediment structures built by the burrowing of the ghost shrimp 23

(Callianassa sp.). Numerous bearded fireworms (Hermodice carunculate) were also observed. We also 24 noted the presence of the giant anemone (Condylactis gigantean) (Figure 16). Benthic invertebrates were 25 also observed on the bulkhead walls and included the urchins (lime urchin [Diadema antillarum], reef 26 urchin [Echinometra viridis], slate pencil urchin [Eucidaris tribuloides], variegated sea urchin [Lytechinus 27 variegatus] and white sea urchin [Tripneustes ventricosus]) as well as the variegated feather duster worm, 28

(Bispira variegate) and the social feather duster worm, (Bispira brunnea). 29

Figure 14. Large areas of sand covered with the calcareous green algae (Penicillus capitatus) (Source: 2

Dial Cordy, 2019) 3

Figure 15. Drift algae composed mainly of the brown algae (Dictyota spp.) was common throughout 5 the surveyed area (Source: Dial Cordy, 2019) 6

Figure 16. Benthic invertebrates observed in the bottomlands fronting the bulkhead: (A) volcano-2 shaped sediment structures built by the burrowing of the ghost shrimp (Callianassa sp.), (B) bearded 3 fireworm (Hermodice carunculate), (C) giant anemone (Condylactis gigantean), (D) giant hermit crab 4

(Petrochirus diogenes), (E) variegated feather duster worm, (Bispira variegate), (F) variegated sea 5 urchin, (Lytechinus variegatus) (Source: Dial Cordy, 2019) 6

Numerous stony corals (36) were also found in the project area (Figure 17 and 18; Table 5). Only one 7 colony of the ESA Listed coral Mountainous Star Coral (Orbicella faveolata) was noted in the project area 8

(Figure 19). Most stony corals were found on debris scattered throughout the site (Figure 20). Large 9 amounts of trash and debris, especially tires were found throughout the project site (Figure 21). 10

Table 5. Coral species noted in bottomlands 11

Species Common Name <5 cm 5– 10 cm >10– 50 cm >50 cm

PAST Mustard Hill Coral numerous 10 5 -

PPOR Finger Coral numerous 9 1 -

SSID Massive Starlet Coral few 5 2 -

SRAD Lesser Starlet Coral numerous - - -

FFRA Golf Ball Coral few - - -

SINT Blushing Star Coral - - 1 -

OANN (sp. comp.)* Star Coral - - 1 -

PSTR Symmetrical Brain Coral - 1 1 -

Figure 17. Four coral species found in the bottomland habitat fronting the bulkhead: (A) mustard hill 2 coral (Porites astreoides), (B) branching finger coral (Porites porites), (C) massive starlet coral 3

(Siderastrea siderea), (D) blushing star coral (Stephanocoenia intersepta) (Source: Dial Cordy, 2019) 4

Figure 18. Isolated colony of Symmetrical Brain Coral (Pseudodiploria strigosa) found on rubble 6 bottom in easternmost portion of the project area (Source: Dial Cordy, 2019) 7

Figure 19. Isolated colony of the ESA-listed coral Lobed Star Coral (Orbicella annularis) species 2 complex found on cement structure within the project boundary (Source: Dial Cordy, 2019) 3

Figure 20. Corals found scattered on hard debris throughout project site (Source: Dial Cordy, 2019) 5

Figure 21. Tires and other debris were found scattered throughout the project site (Source: Dial Cordy, 2

2019) 3

2.4 Project Concerns and Mitigation 4

During construction activities avoidance and minimization measures should be employed to keep seagrass 5 impacts to a minimum. Based on the results of the bottomlands survey, several areas within the project 6 area have been delineated in order to reduce or remove any risk of damage during construction (Figure 7

22). These areas include portions of the project area that are adjacent to or include high densities of 8 seagrass and/or ESA-listed corals. There are three main sections. In the red section, it is recommended 9 that no construction-related activity occur from the water in this area due to the high prevalence of turtle 10 grass (T. testudinum) and shallow depth in the area. Surface buoys should be used to cordon off this area. 11

It is recommended that construction activities be conducted from the wharf bulkhead to reduce impacts. 12

In the orange section, it is recommended that construction-related activities exercise caution while 13 operating within this area. Reference language needed for Appendix E 14

In this instance, caution would include the minimization of propwash in order to avoid disturbing the 15 exotic invasive seagrass species, exotic paddle grass (Halophila stipulacea), which may aid in its spread 16 throughout the site by asexual fragmentation of the plant rhizomes. The use of on-site scientific divers 17 should also be employed when operating in this area to survey potential spudding locations in order to 18 reduce impacts to existing benthic organisms. In the green section, it is also recommended that 19 construction-related activities exercise caution while operating within this area but, given that this area is 20 largely constituted by sand and rubble, it may not be necessary to survey potential spudding locations. 21

However, given this area’s close proximity to adjacent seagrass beds, it is still recommended that 22 propwash be kept to a minimum. In the event that seagrass beds are impacted, these can be mitigated 23 after the fact if necessary using standard seagrass restoration protocols established in Fonseca et al. 24

1998). 25

Approximately 498 coral colonies greater than or equal to 5 cm that are present within the area of direct 26 or indirect construction impacts shall be relocated prior to construction (USCRTF 2016). These corals 27 should be moved in concert with the coral relocation efforts associated with the corals presently living on 28 the bulkhead wall (see Coral Mitigation Plan). During construction, it is recommended that a biologist be 29 on-site as an observer to (1) assist the contractor in avoidance and minimization measures during 1 placement of equipment, and (2) to watch for mobile ESA-listed species such as sea turtles and marine 2 mammals coming into the project area. 3

CHRI 217021 Replace Wharf Bulkhead Seagrass/Coral Surveys & Mitigation Plan (Tt Rev. 01)

Figure 22. Avoidance and impact minimization areas within project area (Source: Dial Cordy, 2019) 2

CHAPTER 3. CORAL MITIGATION PLAN 1

In order to avoid and minimize impacts to stony corals present on the bulkhead structure and within 2 the adjacent bottomlands the approximately 498 stony corals (> 5cm, see Table 6) documented during 3 the Benthic Resource Survey (Dial Cordy, 2018) that are reasonable candidates for relocation will be 4 removed from the bulkhead structure and reattached to competent substrate on a natural reef within 5

Christiansted Harbor. The approximately 35 corals documented (see Table 6) on debris, rubble, 6 boulders, and other structures on the bottomlands immediately adjacent to the bulkhead will be 7 relocated to suitable habitat adjacent to the construction area but outside of the construction 8 footprint. A potential area for relocation is within a rubble/seagrass/sand area in front of the Fort 9

(Figure 24, Site 4); relocated corals and associated substrate would be moved to this or other suitable 10 location in sand or rubble but avoid impact to any existing insitu corals and seagrass 11

Table 6. Size distribution and abundance by coral species to be relocated. 12

Location Species Common Name 5– 10 cm

<10– 50 cm

>50 cm

Bulkhead PAST Mustard Hill Coral 10 63 2

PPOR Club Finger Coral 24 50 -

SSID Massive Starlet Coral 5 20 2

SRAD Lesser Starlet Coral 9 - -

FFRA Golf Ball Coral 3 - -

EFAS Flower Coral - 1 -

SINT Blushing Star Coral 1 - -

DSTO Elliptical Star Coral 4 - -

CNAT Boulder Brain Coral 3 10 5

OANN (species complex complex*)

Lobed, Boulder Star, Mountainous Star Coral

19 7

PSTR Symmetrical Brain Coral 20 126 11

PCLI Knobby Brain Coral - 84 13

MMEA Maze Coral 3 - -

AAGA Lettuce Coral 1 - -

ALAM Whitestar Sheet Coral - - 1

MAER Rose Coral 1

Totals 84 373 41

Bottomlands PAST Mustard Hill Coral 10 5 -

PPOR Finger Coral 9 1 -

SSID Massive Starlet Coral 5 2 -

SRAD Lesser Starlet Coral - - -

FFRA Golf Ball Coral - - -

SINT Blushing Star Coral - 1 -

OANN (sp.

comp.)*

Star Coral - 1 -

PSTR Symmetrical Brain Coral 1 1 -

Totals 25 11 0

*The ESA-Listed Orbicella species are lumped into OANN species complex category. The Lobed Star Coral 1 (Orbicella annularis) species complex is comprised of three closely related species, Lobed Star Coral (O. 2 annularis), Boulder Star Coral (O. franksi), and Mountainous Star Coral (O. faveolata). 3

All coral relocation activities will be conducted following the guidelines established in the Florida Keys 4

National Marine Sanctuary (FKNMS) Coral Rescue and Relocation Protocol (FKNMS 2013), the Coral 5

Transplantation Protocol included in USCRTF (2016), and the USVI DPNR Coral Mitigation Relocation 6

Recommendations (USVI DPNR, Jan 2020). 7

Corals selected for relocation shall meet the following general criteria: 8

• All corals ≥ 5 cm (measured as live tissue diameter) 9

• All ESA-listed corals (no minimum size requirement) 10

• Corals that do not exhibit any outward symptoms of disease 11

In order to ensure the success of the coral relocation and to minimize secondary impacts during the 12 mitigation efforts, it is recommended that this work be performed when certain environmental 13 conditions are met. Due to the shallow water depths at the recipient sites, work should only be 14 performed during relatively calm sea conditions (i.e., wind speeds no greater than 10-12 knots). If 15 weather conditions are too rough (seas greater than 3-ft.), visibility too poor (less than 10 ft.), or wave 16 surge or tidal current is too great (greater than 0.5 knots) to achieve quality reattachments, daily 17 activities would be aborted and rescheduled during better weather. Additionally, stony coral bleaching 18 threshold is 29.5° Celsius (NOAA, 2020); therefore, coral relocation activities should be conducted if 19 water temperatures are near the bleaching threshold. based on historical sea surface temperature 20 data for the USVI the DPNR and the NPS recommends that all relocation should be completed before 21

July 31 (see Figure 23, below). 22

Figure 23. Sea surface temperatures for the USVI from 01 Jan 2001 to 30 March 2020 (Source: 1

NOAA, 2020) 2

3.1. Recipient Site Selection 3

A recipient site survey was completed on January 28 and 29, 2020 to locate suitable habitat for 4 relocation of the stony corals located on the bulkhead structure and adjacent bottomlands. Detailed 5 results of the recipient sites and the selection process are presented in the Coral Relocation and 6

Monitoring Services – Coral Recipient Site Assessment Report (Tetra Tech, 2020). The site assessment 7 survey evaluated potential sites to determine if there is suitable substrate and sufficient habitat area 8 to support corals to be relocated. Following guidance from the USVI DPNR Coral Relocation Site 9

Selection Criteria (USVI DPNR Jan 2020), recipient sites were evaluated for the following information 10 during the survey: 11

• Historic presence of the species to be relocated at the relocation (recipient) site. 1

• Depth—similar to that of donor site (5-10 ft.) 2

• Water quality—qualitatively similar to that of donor site (temperature, visual clarity, and 3 apparent turbidity) 4

• Water circulation in relation to the donor site (e.g., tidal influence). 5

• Light regime—qualitatively similar to that of donor site (visible light penetration and length of 6 daily light exposure). 7

• Orientation of reattachment. 8

• Presence/absence of loose rubble. 9

• Energy—wave action and current similar to that of donor site. 10

• Substrate stable and relatively free of significant cracks or erosion (including framework 11 cracks, coral fragments and coral rubble). 12

• Substrate relatively free of attached benthic organisms such as sponges, calcareous algae, 13 bryozoans, stony coral, octocorals, etc. 14

• Substrate with ample water circulation, comparable water quality, and ambient sunlight for 15 transplantation, and with similar conditions to which the donor or displaced corals are 16 acclimated. 17

• Substrate elevated within the reef structure to avoid the potential for smothering through 18 sedimentation. Preferred sites include bio-eroded or excavated dead areas of coral heads 19 elevated within the water column. 20

• Substrate having similar orientation to donor site. If corals are from a vertical or sloped, 21 elevated surface, then sloping (if not vertical) areas off the bottom shall be identified where 22 possible, especially for plating colonies. 23

• Substrate must exhibit the presence of the species to be attached, as naturally occurring within 24 the benthic community chosen, to enhance survivability. 25

• Availability of adequate space relative to naturally occurring coral colonies such that 26 placement will allow for colony growth, tissue re-colonization and plating. (Inspect other 27 colonies of like species for maximum sizes to identify adequate spacing considerations). 28

• The recipient site must not be located within a direct or indirect impact area for any permitted, 29 authorized or reasonably foreseeable marine coastal construction activity (e.g., dredging, 30 pipeline or communication cable installations), or in areas subjected to repeated disturbance 31 by anthropogenic impacts such as repeated vessel groundings. 32

Four recipient sites that met the intent of the evaluation criteria were delineated during the surveys. 33

Three recipient sites are located on the north end of Round Reef and one is located to the east of the 34 donor site. Figure 23 presents the locations of the selected recipient sites. Table 7 provides the central 35 coordinates for each recipient site. A brief description of the selected recipient sites follows. 36

Table 7. Recipient site coordinates (NAD83, UTM 20N, Meters). 1

Recipient Site X (meters) Y (meters)

1 1597038.2 1993567.4

2 1596913.1 1993551.7

3 1596861.3 1993508.1

4 1596626.1 1992519.8

Recipient Sites 1 and 2, described together due to their proximity and similar conditions, are north-2 facing, gradual to vertical reef slopes on the north side of Round Reef. The orientation, available 3 substrate, water quality, depth, and energy make these sites optimal for relocation of all species and 4 size classes and the preferred recipient sites for the larger (≥50 cm) stony corals. Species richness, coral 5 cover, and size class are in line with those of the donor site. In order to attempt to provide similar 6 lighting conditions, protection from vessel groundings, and other potential disturbances, the 7 recommended relocation depth is between 8-20 ft. below water surface (BWS). At this depth range 8 suitable relocation substrate is readily available. Suitable reattachment substrate is readily available 9 throughout. Additionally, the substrate is generally clear of turf and/or decumbent algae, gorgonians, 10 and other epibenthic fauna. 11

Recipient Site 3 is a northwest-facing shallow vertical reef on the Northwest side of Round Reef. An 12 abundance of small terraces on the vertical reef face provide suitable relocation habitat for smaller 13 colonies (≤25 cm). Water quality, depth, energy, light regime, species richness, and coral cover are 14 similar to the donor site. The recommended depth range is 5-9 ft. BWS. Suitable reattachment 15 substrate is available along the small terraces. The substrate is generally clear of turf and/or 16 decumbent algae, gorgonians, and other epibenthic fauna. 17

The remnants (destroyed during previous hurricanes) of A United State Coast Guard (USCG) Aid to 18

Navigation (ATON) is located between Recipient sites 2 and 3 (see Figure 24). The USCG is responsible 19 for maintaining the ATONs along declared navigable waterways. Removal and/or repair of the 20 degraded ATON may result in impacts to nearby stony corals. Communications with the USCG 21 confirmed that a project to replace ATONs (lights 9 and 11) is moving forward. The location of the 22

ATON is not within the boundaries of recipient Sites 2 and 3 (see Figure 24); however, to mitigate 23 against potential future impacts associated with replacement of the ATON, stony corals will not be 24 reattached within a 100-ft. radius of an ATON. 25

Recipient Site 4 is a shallow (3-6 ft. BWS) discontinuous seagrass community just north of the donor 26 site (bulkhead structure). The dominant seagrass species is Thalassia testudinum. Orientation, 27 available substrate, water quality, depth, and energy make this site optimal for relocation of colonies 28 that are attached to rubble and debris on the seafloor along the base of the bulkhead. Colonies 29 attached to loose rubble and debris will be relocated and placed in an upright orientation in areas 30 devoid of seagrass. 31

Figure 24. Green boxes present the extent of the delineated recipient sites for reattachment of 1 relocated corals from the donor site (CHRI bulkhead) and the the bottamlands adjacent to the 2 bulkhead (Source:Tetra Tech, 2020) 3

3.2. Coral Handling and Decontamination Procedures 1

Rubber gloves will be worn while handling corals to minimize mucous removal and abrasion. Corals 2 exhibiting any symptoms of stress, bleaching, or disease will not be relocated to prevent the risk of 3 disease transmission at the recipient site. If a coral displays signs of disease pursuant to the US Virgin 4

Islands DPNR Coral Visual Health Assessment Criteria (USVI DPNR Jan 2020) during coral relocation or 5 monitoring activities, decontamination protocol adopted from AMLC Disease Workshop 2017, et al. 6

(Appendix B) will be employed to prevent further spread of disease. Additionally, corals colonized by 7 clionid sponges will not be relocated from the donor site. National Park Service Resource Management 8

(NPS RM) staff will conduct a visual health assessment the week prior to the relocation to confirm coral 9 health and water temperature are appropriate. Additionally, NPS RM staff will participate in visual 10 health assessments throughout the relocation activities. 11

3.3. Coral Removal and Relocation Protocol 12

Removal, relocation and reattachment methodologies will include a variety of hand tools (putty knives, 13 paint scrapers, chipping hammers, other thin bladed, prying tools with beveled edges, and baskets or 14 buckets). Chisels with wide and thin blades may also be utilized, but these are generally too thick-15 bladed and can cause fragmentation of the coral colony due to narrowly focused transfer of hammer 16 strikes. No power tools or heavy pry bars will be utilized. The vibration and/or transfer from these 17 tools cause fragmentation of plating coral colonies. Rubber gloves will be worn while handling corals 18 to minimize mucous removal and abrasion. Corals exhibiting any symptoms of disease will not be 19 relocated to prevent the risk of disease transmission at the recipient site. Figure 24 presents the coral 20 relocation activities graphically. Steps involved in the selection and removal of corals from the 21 bulkhead are as follows: 22

• Only coral candidates that do not exhibit symptoms of stress, bleaching, disease, or signs of 23 sponge predation (Cliona spp.) will be removed for relocation. 24

• Removal will be initiated by clearing all encrusting organisms (e.g., sponges, tunicates, 25 mollusks) from the edges of the corals. Care will be taken to prevent damage to the thin edges 26 of corals. Once removed, this creates an access point/edge to begin loosening the coral from 27 the attachment surface. 28

• Once an edge has been established, putty knives and/or other stiff, thin-bladed, beveled-edge 29 tools will be carefully inserted by hand and/or with hammers around the entire circumference 30 of colony (see Figure 25). 31

• This process will continue until the colony loosens and limestone dust is observed from 32 underside of colony indicating that the base has been separated from the substrate. 33

• Significant time and effort will be taken to remove the coral colony in a single piece. If corals 34 are not able to be removed in a single piece (e.g., encrusting coral species), care will be taken 35 to limit breakage to a minimum. Pieces from the same colony will be kept together and 36 reconstructed/reattached as close together as possible at the recipient site to promote 37 successful fusing. 38

• Once removed, corals will be placed in an upright position in a designated temporary cache 39 site near the bulkhead structure. 40

• Coral cache shall be in an area with similar light, depth, and energy conditions. 41

• Coral cache shall not be located on softbottom. Coarse sand, rubble, and seagrass habitat are 42 suitable temporary cache locations. 43

• Corals may be placed in the cache site directly on the seafloor or in crates/receptacle/baskets. 44

• Corals shall be transported to the recipient site in a single layer in transport 1 crates/receptacle/coolers/baskets. 2

• Corals may be transported in the dry (covered with wet towels or bubble wrap) or in the wet 3

(submerged in water). Corals shall remain covered or in the shade while topside. 4

• Once all transport storage space is occupied, the cache of corals will be transported to the 5 recipient site for transplant. 6

• Due to the large number of corals to be transplanted, multiple trips to the recipient site will 7 be required. 8

• Once the corals have arrived at the recipient site, they must be immediately transferred to a 9 designated cache site within the recipient site. 10

• Corals may be cached at the recipient site directly on the seafloor or in transport 11 crates/receptacle/baskets. 12

• The recipient site cache site shall be relatively bare so as not to impact pre-existing epibenthos. 13

• Divers participating in coral reattachment activities will transfer corals from the cache site to 14 the reattachment location in transfer receptacles/baskets. 15

Figure 25. (A) Scientific diver carefully removing coral colony for relocation, (B) large Siderastrea 18 colony being carefully removed from wall, (C) diver carrying colony following removal, (D) plastic 19 bin used to cache and transport corals after removal, (E) colony of (Porites astreoides) reattached 20 on natural hardbottom surface (grey coloration is Portland cement), (F) diver monitoring the status 1 of relocated corals (Source: Dial Cordy, 2019) 2

3.4. Coral Reattachment Protocol 3

Corals removed from the Christiansted bulkhead will be pe permanently reattached using a bonding 4 agent such as cement or epoxy to suitable substrate within the selected recipient sites. Corals will be 5 immediately reattached upon arrival to the recipient site to minimize the amount of time the corals 6 are unattached to substrate. Coral reattachment activities will be conducted following the guidelines 7 established in the FKNMS Coral Rescue and Relocation Protocol (FKNMS 2013). When reattaching 8 corals, the following steps will be employed: 9

• Colonies will be placed an adequate distance from one another to allow for colony growth, 10 tissue re-colonization, and plating. Other colonies of like species will be inspected for 11 maximum sizes to identify adequate spacing considerations. 12

• Care will be taken to place coral colonies an adequate distance from naturally occurring 13 colonies due to the potential of interspecific aggression (competition) between colonies. 14

• Ideal orientation will be chosen, if possible (i.e., corals from a vertical/sloped area such as a 15 seawall or an elevated surface, will be placed in a similar orientation). 16

• When selecting the recipient surface, areas of relatively bare substrate will be selected to the 17 maximum extent possible. 18

• The recipient surface(s) will be prepped with a wire brush and/or chipping hammer: removing 19 all algae (macro, fine filamentous), sediment, silt, encrusting and boring organisms (if present). 20

Care will be taken to avoid other corals or those obscured by macro algae (i.e., coral recruits). 21

• The underside of each coral colony to be reattached will be prepped by removing any algae, 22 sediment, silt, boring organisms, (sponges, tunicates, worms, crustaceans, etc.). 23

• Reattachment of corals will be completed by divers using a thick, non-flowing concrete mix 24

(Portland Type II cement (if available) with a sand mix in a 3:1 ratio). 25

• Using an electric drill, the concrete will be mixed on the boat and in 5-gallon buckets with lids. 26

• Each mixing bucket will include a lid attached to the bucket handle with a string. 27

• Once the concrete has been mixed to the appropriate thick consistency, the bucket is sealed, 28 and delivered to the diver reattaching corals. Using sealed buckets reduced cement “fall-out” 29 during the cement transfer and reattachment process 30

• The diver reattaching corals will crack the lid and reach into the cement bucket to grab an 31 appropriate-sized ball of concrete. The ball of concrete is then placed on the prepared surface. 32

The coral colony will be placed on top and pressed down by gently wiggling colony, allowing 33 the concrete to spread and encompass bare edges of coral colony base. Concrete will be 34 sculpted around base of coral to cover or fill in bare rock surfaces. Concrete is added or 35 removed as necessary around the edge of the colony to create a clean appearance, reduce 36 bioerosion, provide a growing surface, and provide a strong bond with the substrate. Excess 37 concrete is gathered and placed back into the bucket. 38

• Once the colony has been set into the concrete, additional adjustment is not advised as it may 39 introduce stress fractures in the cement bond leading to partial or total failure of attachment. 40

• Contact of concrete with live surface of coral and all coral tissue will be minimized to the 41 maximum extent possible. Divers will maintain clean, gloved hands while handling and placing 42 coral colonies on top of concrete pads. 43

• Once coral colony is placed on concrete, all tissue will be immediately fanned by hand to 44 remove any residual concrete that has come into contact with live coral surfaces before it 45 becomes imbedded in tissue mucous or polyp calices. At all times, extreme caution will be 1 taken to prevent cement "fall-out" from landing on living tissue. Small lumps and cement 2 particulate that accidentally settle out on living coral should immediately be removed via 3 fanning. The work area and adjacent areas will be inspected for "fall-out" periodically 4 throughout the workday to prevent impacts from excess cement. 5

• All excess cement will be collected from the transplant site and disposed of off-site (land 6 based). No excess cement will remain underwater. 7

3.5. Mooring Installation 8

Repetitive anchoring with standard ground tackle (e.g., Danforth standard marine anchor) poses a 9 potential hazard to coral reef and seagrass habitat. To facilitate the work and avoid damaging the 10 sensitive habitat, mooring locations will be installed at the recipeint sites and donor location (bulkhead 11 structure). Moorings will be secured on the seafloor by divers in areas clear of epibenthic biota. Divers 12 will ensure damage is not caused to surrounding biota by the downline during tidal sweeps. Moorings 13 will non-permanent standard anchoring devices (e.g., Danforth standard marine anchor) attached to a 14 sub-surface bouy. Divers will attach a surface line to the sub-surface bouy at the beginning of each day. 15

The use of a subsurface bouy will detract the attention of boaters in the area. Morrings may be moved 16 as necessary during field operations. 17

3.6. Staging Area 18

Materials will be staged out of CHRI. The work vessel will remain moored in Christiansted Harbor 19 during non-qorking hours. Daily vessel loading will occur at the dock near the western end of the 20

CHRI bulkhead structure. Care will be taken not to disturb Park operations during loading and 21 unloading of equipment and materials. 22

3.7. Inclement Weather Operations 23

Weather forecasts and NOAA weather radio will be monitored by the designated topside support 24 personnel.