B08_Section_J_Attachment_6_Benthic_Survey.pdf

Fort Jefferson- Counterscarp- Coral and Benthic Survey DRTO 244370

FORT JEFFERSON

Fort Jefferson Small Craft Dock Benthic Survey

Fort Jefferson Small Craft Docks Coral and Seagrass Survey

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 2 of 35 November 16, 2020

Contents Introduction

Survey Methodology

Small Craft Docks

Moat Survey

Results

Small Craft Docks

Moat Survey

Appendix A Coral Locations and Measurements

Appendix B Small Craft Docks Representative Photos

Figure 1 - Project Location

Figure 2 - Survey Location

Figure 3 - Small Craft Dock Survey Area

Figure 4 Small Craft Docks Survey - Slip One Corals

Figure 5 Small Craft Docks Survey - Slips Two and Three Corals

Figure 6 Small Craft Docks Survey - Slip Four Corals

Figure 7 Small Craft Docks Survey - Slip Five Corals

Figure 8 Small Craft Docks Survey – Slip Six and Seven Corals

Figure 9 – Small Craft Docks Survey – SAV

Figure 10 – Southwestern Sand Deposit

Figure 11 – Northeastern Sand Deposit

Figure 12 – Mapped SAV

Table 1 Small Craft Dock- Coral Species Observed

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 3 of 35 November 16, 2020

Introduction On September 19th and 20th of 2020, Schneider Engineering Consulting (SEC) conducted a Benthic Habitat Survey at Fort Jefferson, Florida (Please refer to Figure 1- Project Location). This survey was conducted in support of the proposed maintenance dredging at the small craft docks and the removal of sand deposits within the moat surrounding the fort. The survey identified stony corals, octocorals and seagrasses growing in the area of the small craft docks and the areas surrounding the sand deposits within the moat. The survey was conducted by marine scientists Benjamin Brice (SEC), and Joshua Kohlbecker (Cooper K Environmental). During the survey, the substrate and structures of the small craft docks along with the two sand deposits within the moat surrounding the main fort were inspected. The depth of the water at the site ranged from 0 to 10 feet. Visibility ranged from 3 to 20 plus feet horizontally.

Figure 1 - Project Location

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 4 of 35 November 16, 2020

Survey Methodology

Small Craft Docks

The survey of the small craft docks was conducted via diver transects to identify limits of

Submerged Aquatic Vegetation (SAV) and presence of coral species. Species present and estimates of coverages were recorded for SAV observed and coral species were documented. For coral colonies greater than 10 cm in any dimension, the length, width, and height were recorded.

Representative photographs were also collected of coral species observed. To facilitate the collection of data on the coral colonies, a field sketch was created of each of the structures surveyed. The sketches were used to identify the dominate cardinal direction of the structure where the colonies were recorded. Limits of the observed SAV were recorded via a Trimble GEO XH unit. It should be noted that coral colonies were only observed on the hard structures of the small craft docks.

Moat Survey

The limits of SAV within the moat surrounding the fort were previously surveyed during the counterscarp survey conducted in November 2019. The survey was accomplished with diver transects to identify limits of SAV within the moat. The limits of the observed SAV were recorded via a Trimble GEO XH 6000 unit. Since the 2019 survey, multiple weather events have impacted the fort and the previously documented sand deposits. To document the changes in the extents of the sand deposits, the limits (toe of slope) were mapped via the Trimble GEO XH unit and overlaid with the previous SAV survey data.

Figure 2 presents the locations of the different survey components.

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 5 of 35 November 16, 2020

Figure 2 - Survey Location

Results

Small Craft Docks

A total of 65 colonies of corals and 1,246 ft2 of SAV were observed during the survey of the small craft docks and the surrounding area. The 65 coral colonies consisted of 12 species of stony corals and 3 species of soft corals. Two colonies of the listed species Orbicella faveolata were observed during the Small Craft Docks Survey. Table 1 presents the all the coral species identified within the small craft docks survey area and their total number of occurrences per species. Please see Appendix A for the measurements of the species observed and Appendix B for representative photos of the species observed.

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 6 of 35 November 16, 2020

Table 1 Small Craft Docks - Coral Species Observed

Table 1 Small Craft Docks - Coral Species Observed

Species Number of occurrences Species

Number of occurrences

Agaricia agaricites (St) 4 Millepora alcicornis (St) 11

Antillogorgia americana (So) 1 Oculina diffusa (St) 5

Colpophyllia natans (St) 1 Orbicella faveolata (St) 2

Dichocoenia stokesii (St) 1 Porites astreoides (St) 15

Dmanicina areolata (St) 1 Pseudodiploria clivosa (St) 5

Eunicea flexuosa (So) 2 Pseudodiploria strigosa (St) 5

Eunicea sp. (So) 3 Siderastrea radians (St) 5

Favia fragum (St) 4

* Stony Coral (St), Soft Coral (So)

For the purposes of the survey, the slips were numbered 1 through 7 and the piers were numbered 1 through 6 starting on the northeastern end of the project site. Figure 3 identifies the overall survey area. Figures 4 through 8 show the locations where coral colonies were observed and lists the species that was observed in each location.

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 7 of 35 November 16, 2020

Figure 3 - Small Craft Dock Survey Area

Figure 4 Small Craft Docks Survey - Slip One Corals

Within Slip 1, 12 individual coral colonies consisting of 8 different species were observed. Of special note were the 2 colonies of Orbicella faveolata, which is listed as endangered.

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 8 of 35 November 16, 2020

Figure 5 Small Craft Docks Survey - Slips Two and Three Corals

Within Slips 2 and 3, 19 coral colonies were observed. The 19 colonies consisted of 9 different species of corals, with Millepora alcicornis being the most common.

Figure 6 Small Craft Docks Survey - Slip Four Corals

Within Slip 4, 6 coral colonies were observed. These consisted of 6 different species, again with

Millepora alcicornis being the most common.

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 9 of 35 November 16, 2020

Figure 7 Small Craft Docks Survey - Slip Five Corals

Within Slip 5, 9 colonies of coral were observed. The colonies were composed of 7 different species of corals.

Figure 8 Small Craft Docks Survey – Slip Six and Seven Corals

Within Slips 6 and 7, 19 colonies of coral were observed. The colonies were composed of 7 different species of corals, with Porites astreoides being the most common.

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 10 of 35 November 16, 2020

The SAV identified within the survey footprint for the small craft docks area consisted solely

Thalassia testudinum. To the southwest of Pier 6, an isolated patch of Thalassia testudinum was observed. The area of Thalassia ranged in coverage from 5 percent density at the outer edges and up to 80 percent in the interior. The total of the mapped Thalassia testudinum was 1,246 ft2.

See Figure 9 for location and extent of the mapped Thalassia testudinum.

Figure 9 – Small Craft Docks Survey – SAV

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 11 of 35 November 16, 2020

Moat Survey

The limits of the sand deposits were mapped with the Trimble GEO XH on both the southwestern and northeastern sand deposits. These recorded changes were then overlaid with the original SAV mapping data. Movement of the two sand deposits accounted for reduction of 562 ft2 of SAV within the moat. Figure 10 depicts the changes in the southwestern sand deposit. On the eastern side of the deposit, the movement of the sand encroached on 362 ft2 of SAV. The sand movement on the western side of the deposit had no impacts to the previously mapped SAV.

Figure 10 – Southwestern Sand Deposit

At the northeastern sand deposit, only the southern interface of the sand deposit had impacts to the mapped SAV. This impact consisted of 201 ft2 SAV. See Figure 11 for changes to northeastern sand deposit.

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 12 of 35 November 16, 2020

Figure 11 – Northeastern Sand Deposit

With the reduction in SAV coverage due to the sand desposit movements there is now a coverage of 1.92 acres of SAV within the moat verses the previouly mapped 1.93 acres. See Figure 12 for location of mapped SAV.

It should be noted that seagrass limits are constantlty in flux, due to die off and expansion of colonies, as well as ever changing sand movement as seen with the recorded surveys.

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 13 of 35 November 16, 2020

Figure 12 – Mapped SAV

Appendix A Coral Locations and Measurements

Fort Jefferson- Counterscarp- Coral and Benthic Survey DRTO 244370

ID #

Depth from

Top of

Structure

Length Width Height Species

1 96 10 10 1.5 Porites astreoides

2 94 14 26 2 Agaricia agaricites

3 63 >10cm Favia fragum

4 108 34 42 1 Orbicella faveolata

5 45 2 2 10 Eunicea sp.

6 52 2 9 11 Eunicea sp.

7 44 10 7 8 Eunicea sp.

8 86 1 60 44 Eunicea flexuosa

9 82 39 65 13 Orbicella faveolata

10 104 24 26 9 Dichocoenia stokesii

11 63 17 14 11 Oculina diffusa

12 >10cm Porites astreoides

13 60 10 15 3 Pseudodiploria strigosa

14 61 11 14 4 Pseudodiploria strigosa

15 97 30 30 5 Pseudodiploria clivosa

16 107 13 17 7 Oculina diffusa

17 113 >10cm Agaricia agaricites

18 44 16 16 7 Millepora alcicornis

19 54 18 44 34 Eunicea flexuosa

20 82 21 29 5 Millepora alcicornis

21 44 14 18 7 Millepora alcicornis

22 55 20 23 5 Porites astreoides

23 68 27 40 9 Millepora alcicornis

24 83 10 9 2 Porites astreoides

25 88 14 9 1 Millepora alcicornis

26 44 120 40 27 Millepora alcicornis

27 46 44 48 6 Pseudodiploria clivosa

28 66 40 28 8 Colpophyllia natans

29 78 >10cm Favia fragum

30 58 30 29 7 Pseudodiploria clivosa

31 38 48 60 14 Millepora alcicornis

32 74 48 21 8 Pseudodiploria strigosa

33 50 10 8 1 Agaricia agaricites

34 55 47 53 8 Pseudodiploria clivosa

35 64 32 20 4 Millepora alcicornis

36 42 14 10 9 Oculina diffusa

37 69 72 44 46

Antillogorgia americana

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 15 of 35 November 16, 2020

ID #

Depth from

Top of

Structure

Length Width Height Species

38 104 41 29 2 Millepora alcicornis

39 104 41 109 5 Millepora alcicornis

40 108 9 14 3 Porites astreoides

41 78 13 15 16 Oculina diffusa

42 123 11 9 2 Porites astreoides

43 111 10 7 2 Siderastrea radians

44 117 19 6 3 Porites astreoides

45 >10cm Agaricia agaricites

46 >10cm Dmanicina areolata

47 102 41 33 13 Millepora alcicornis

48 108 10 8 1 Pseudodiploria clivosa

49 107 12 17 2 Porites astreoides

50 75 6 10 2 Porites astreoides

51 >10cm Favia fragum

52 >10cm Pseudodiploria strigosa

53 94 10 12 1 Porites astreoides

54 80 7 2 1 Pseudodiploria strigosa

55 82 15 20 2 Porites astreoides

56 >10cm Siderastrea radians

57 >10cm Siderastrea radians

58 >10cm Favia fragum

59 >10cm Siderastrea radians

60 >10cm Siderastrea radians

61 >10cm Oculina diffusa

62 >10cm Porites astreoides

63 55 15 15 3 Porites astreoides

64 34 >10cm Porites astreoides

65 44 13 11 1 Porites astreoides

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 16 of 35 November 16, 2020

Appendix B Small Craft Docks Representative Photos

Fort Jefferson- Counterscarp- Coral and Benthic Survey DRTO 244370

Small Craft Docks Slip 1 Corals – Photo 1

Small Craft Docks Slip 1 Corals – Photo 2

Porites astreoides.

Agaricia agaricites.

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 18 of 35 November 16, 2020

Small Craft Docks Slip 1 Corals – Photo 3

Small Craft Docks Slip 1 Corals – Photo 4

Orbicella faveolata

Favia fragum

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 19 of 35 November 16, 2020

Small Craft Docks Slip 1 Corals – Photo 5

Small Craft Docks Slip 1 Corals – Photo 6

Dichocoenia stokesii

Eunicea flexuosa

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 20 of 35 November 16, 2020

Small Craft Docks Slip 1 Corals – Photo 7

Small Craft Docks Slip 2 Corals – Photo 1

Pseudodiploria strigosa

Oculina diffusa

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 21 of 35 November 16, 2020

Small Craft Docks Slip 2 Corals – Photo 2

Small Craft Docks Slip 2 Corals – Photo 3

Pseudodiploria clivosa

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 22 of 35 November 16, 2020

Small Craft Docks Slip 2 Corals – Photo 4

Small Craft Docks Slip 2 Corals – Photo 5

Agaricia agaricites

Millepora alcicornis

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 23 of 35 November 16, 2020

Small Craft Docks Slip 2 Corals – Photo 6

Small Craft Docks Slip 2 Corals – Photo 7

Colpophyllia natans

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 24 of 35 November 16, 2020

Small Craft Docks Slip 3 Corals – Photo 1

Small Craft Docks Slip 3 Corals – Photo 2

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 25 of 35 November 16, 2020

Small Craft Docks Slip 3 Corals – Photo 3

Small Craft Docks Slip 4 Corals – Photo 1

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 26 of 35 November 16, 2020

Small Craft Docks Slip 4 Corals – Photo 2

Small Craft Docks Slip 4 Corals – Photo 3

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 27 of 35 November 16, 2020

Small Craft Docks Slip 4 Corals – Photo 4

Small Craft Docks Slip 4 Corals – Photo 5

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 28 of 35 November 16, 2020

Small Craft Docks Slip 4 Corals – Photo 6

Small Craft Docks Slip 5 Corals – Photo 1

Antillogorgia americana

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 29 of 35 November 16, 2020

Small Craft Docks Slip 5 Corals – Photo 2

Small Craft Docks Slip 5 Corals – Photo 3

Porites astreoides

Siderastrea radians

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 30 of 35 November 16, 2020

Small Craft Docks Slip 5 Corals – Photo 4

Small Craft Docks Slip 5 Corals – Photo 5

Manicina areolata

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 31 of 35 November 16, 2020

Small Craft Docks Slip 6 Corals – Photo 1

Small Craft Docks Slip 6 Corals – Photo 2

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 32 of 35 November 16, 2020

Small Craft Docks Slip 6 Corals – Photo 3

Small Craft Docks Slip 6 Corals – Photo 4

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 33 of 35 November 16, 2020

Small Craft Docks Slip 6 Corals – Photo 5

Small Craft Docks Slip 6 Corals – Photo 6

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 34 of 35 November 16, 2020

Small Craft Docks Slip 6 Corals – Photo 7

Small Craft Docks Slip 7 Corals – Photo 1

Fort Jefferson- Small Craft Docks Coral and Seagrass Survey DRTO 244370

Page 35 of 35 November 16, 2020

Small Craft Docks Slip 7 Corals – Photo 2

Small Craft Docks Slip 7 Corals – Photo 3