IN-WATER SEA TURTLE DISTRIBUTION AND ABUNDANCE MONITORING ON PALM BEACH COUNTY NEARSHORE REEFS FOR:

Transcription

1 IN-WATER SEA TURTLE DISTRIBUTION AND ABUNDANCE MONITORING ON PALM BEACH COUNTY NEARSHORE REEFS FOR: Jupiter Carlin Shoreline Protection Project Juno Beach Shoreline Protection Project Singer Island Erosion Control Project Sampling Event 6 September 16, 2009 SUBMITTED BY: Inwater Research Group 4160 N.E. Hyline Dr. Jensen Beach, FL SUBMITTED TO: Palm Beach County Department of Environmental Resources Management 2300 N. Jog Road, 4 th Floor West Palm Beach, FL 334

2 INTRODUCTION This report provides results from the sixth preconstruction survey of in-water sea turtle distribution and abundance monitoring conducted by Inwater Research Group for Palm Beach County. Surveys were conducted to meet permit conditions associated with the Jupiter Carlin Shoreline Protection Project, the Juno Beach Shoreline Protection Project and the Singer Island Erosion Control Project. All surveys were conducted less than 250 meters offshore over hardbottom reef structure or adjacent to nearshore artificial structures that may be affected by project construction and post construction activities. Surveys were also conducted in similar habitat offshore of John D. MacArthur Beach State Park. This area will not be impacted by project activities and serves as a control site for each of the three projects. This in-water sea turtle distribution and abundance monitoring effort is intended to provide data to quantify the effects of the shoreline protection and erosion control projects on the abundance of sea turtles in the project area as compared to concurrent data collected at the control site. This report presents data gathered on September 16, 2009 and is considered part of the baseline data for these projects. Subsequent surveys will be added to these baseline data and will be compared between seasons. These preconstruction surveys will provide a complete baseline dataset that will be used to compare sea turtle abundance in the project areas throughout the construction and post construction phases of the projects. These baseline data will serve as a way to assess the impact that these projects have on marine turtle abundance compared over time and between project and control sites. MATERIALS AND METHODS Aerial surveys have often been used to obtain information on the abundance and distribution of turtles over relatively large areas and are appropriate for documenting seasonal variations in population levels. On the relatively limited geographic scale of Palm Beach County, an analogous vessel based approach is more appropriate. This monitoring effort uses observers that count sea turtles from a small boat and provides an index of sea turtle abundance. Sightings per vessel/kilometer are calculated for each species, allowing for direct comparisons between seasons and areas. The monitoring is conducted from a boat equipped with a spotting tower capable of supporting two observers at an eye level of approximately 12 feet above the water. The GPS waypoints at the north and south ends of each transect line establish a base course that the helmsman follows. A constant vessel speed of 5 to 6 knots is maintained during all transects as vessel track and speed are recorded by GPS. With one observer looking to port and one observer looking to starboard, the vessel proceeds along the transect line. When a turtle is sighted, a GPS waypoint is collected and the turtle is identified to species, life history stage (juvenile, subadult or adult) and distance from transect line. The position of the turtle relative to the transect line (inshore, offshore, or on the transect line) is also recorded. To calculate sightings per unit effort, the number of sea turtles sighted on each transect is divided by the transect length which yields sea turtles sighted per kilometer of effort. These relative abundance data can then be compared between transects and between seasons. Transect Descriptions and Adjustments Jupiter Carlin Shoreline Protection Project Transect 1 (Project Area). Approximately 200 offshore between FDEP Reference markers R-13 and R- 19 (1.60 kilometers) 2

3 Transect 2 (Project Area). Approximately 400 offshore between FDEP Reference markers R-13 and R- 19 (1.60 kilometers) Juno Beach Shoreline Protection Project Transect 3 (Project/Pier Area). 100 parallel to Juno Pier, north, east and south (427 meters) Transect 4 (Project/Pier Area). 300 parallel to Juno Pier, north, east and south (654 meters) Transect 5 (Downdrift Area). Approximately 200 offshore, between FDEP Reference markers R-47 and R-52 (1.60 kilometers) Transect 6 (Downdrift Area). Approximately 400 offshore, between FDEP Reference markers R-47 and R-52 (1.60 kilometers) Singer Island Erosion Control Project Transects 7-10 were adjusted in April 2009 to accommodate changes to the design of the Singer Island Erosion Control Project. Therefore, current transect lengths differ from previous sampling events. Transect 7 (Project Area). Approximately 200 offshore, between FDEP Reference markers R-60.5 and R-66 (1.8 kilometers) Transect 8 (Project Area). Approximately 400 offshore, between FDEP Reference markers R-60.5 and R-66 (1.8 kilometers) Transect 9 (Downdrift Area). Approximately 400 offshore (to enable safe vessel operation), between FDEP Reference markers R-66 and R-72 (1.8 kilometers) Transect 10 (Downdrift Area). Approximately 600 offshore, between FDEP Reference markers R-66 and R-72 (1.8 kilometers) Control Site (John D. MacArthur Beach State Park) for all projects Transect (Control Area). Approximately 200 offshore, between FDEP Reference markers R-52 and R-60.5 (2.33 kilometers) Transect 12 (Control Area). Approximately 400 offshore, between FDEP Reference markers R-52 and R-60.5 (2.33 kilometers) RESULTS AND DISCUSSION The sixth preconstruction survey was conducted on September 16, All surveys were conducted between 0900 and 1400 hours with seas of less than two feet and water visibility of 10 feet or greater. The tables below provide sightings per unit effort, by species (loggerhead {Caretta caretta} and green {Chelonia mydas}) for all transects conducted during all sampling events. There is some variation between sampling events, however there are not enough data to make any meaningful spatial or temporal comparisons. These analyses will be conducted when sufficient seasonal data are collected. A brief description of each transect census effort is provided below. 3

4 Jupiter Carlin Shoreline Protection Project Transect 1. The surface weather conditions were mostly sunny with light and variable winds at 5 knots. Sea surface conditions were smooth. Underwater visibility was fair at 10 feet. Sea surface temperature was 27.7 o C and conditions were deemed acceptable for survey. Survey started at 0921 and ended at No sea turtles were observed during this transect. Transect 2. The surface weather conditions were mostly sunny with light and variable winds at 5 knots. Sea surface conditions were smooth. Underwater visibility was fair at 10 feet. Sea surface temperature was 27.8 o C and conditions were deemed acceptable for survey. Survey started at 0936 and ended at No sea turtles were observed during this transect. During preconstruction transects conducted on September 16, 2009, a total of 3.20 kilometers of transects were conducted in the Jupiter Carlin Shoreline Protection Project project area. No sea turtles were sighted on the inshore or offshore construction site transects. Tables 1&6 and Figures 1-5 present cumulative sighting data in tabular and graphic format. Table 1. Jupiter Carlin Shoreline Protection Project, preconstruction sea turtle sighting data and sightings per unit effort for each transect. Transects conducted in September 2009 are shaded. Green turtles Green turtle sightings per Loggerheads Loggerhead sightings per Transect # Length Date sighted kilometer/transect sighted kilometer/transect /17/ /17/ /16/ /16/ /24/ /24/ /18/ /18/ /1/ /1/ /16/ /16/ Juno Beach Shoreline Protection Project Transect 3. The surface weather conditions were mostly sunny with southeast winds at 5-10 knots. Sea surface conditions were very light chop with wind waves of less than 2 feet. Underwater visibility was good at 15 feet. Sea surface temperature was 27.9 o C and conditions were deemed acceptable for survey. Survey started at 1001 and ended at No sea turtles were observed during this transect. Transect 4. The surface weather conditions were mostly sunny with southeast winds at 5-10 knots. Sea surface conditions were very light chop with wind waves of less than 2 feet. Underwater visibility was good at 15 feet. Sea surface temperature was 27.9 o C and conditions were deemed acceptable for survey. Survey started at 1009 and ended at No sea turtles were observed during this transect. 4

5 Transect 5. The surface weather conditions were mostly sunny with southeast winds at 5-10 knots. Sea surface conditions were very light chop with wind waves of less than 2 feet. Underwater visibility was good at 15 feet. Sea surface temperature was 27.7 o C and conditions were deemed acceptable for survey. Survey started at 1028 and ended at No sea turtles were observed during this transect. Transect 6. The surface weather conditions were mostly sunny with southeast winds at 5-10 knots. Sea surface conditions were very light chop with wind waves of less than 2 feet. Underwater visibility was good at 15 feet. Sea surface temperature was 27.6 o C and conditions were deemed acceptable for survey. Survey started at 1043 and ended at Two juvenile green turtles were sighted during this transect. Details are provided in Tables 2&6. During preconstruction transects conducted for this project on September 16, 2009, a total of 4.29 kilometers of transects were conducted in the Juno Beach Shoreline Protection Project project area. Two juvenile green turtles were sighted on Transect 6, and sightings per unit effort was calculated at 1.25 green turtles per kilometer transect. Tables 2&6 and Figures 1-4 and 7-8 present cumulative sighting data in tabular and graphic format. Table 2. Juno Beach Shoreline Protection Project, preconstruction sea turtle sighting data and sightings per unit effort for each transect. Transects conducted in September 2009 are shaded. Green turtles Green turtle sightings per Loggerheads Loggerhead sightings per Transect # Length Date sighted kilometer/transect sighted kilometer/transect /17/ /17/ /17/ /17/ /16/ /16/ /16/ /16/ /24/ /24/ /24/ /24/ /18/ /18/ /18/ /18/ /1/ /1/ /1/ /1/ /16/ /16/ /16/ /16/

6 Diamondhead Radnor Artificial Reef Point Survey Count Beginning with the April 2009 survey, an additional survey site was added. This area is located north of the Juno Pier and encompasses the Diamondhead Radnor Artificial Reef complex, constructed as mitigation for the first Jupiter Carlin and Juno Beach Shoreline Protection Projects. Due to the relatively small and discrete area covered, a transect survey would not be appropriate for this site, so a stationary point count method was employed. For this count, the vessel remained stationary, and two observers in the elevated tower scanned a 360 degree area around the vessel for a period of 15 minutes and all observations of sea turtles were recorded. During the point survey period on the September 16, 2009 sampling event, no turtles were observed in the vicinity of the artificial reef. Tables 3&6 and Figure 6 present cumulative sighting data in tabular and graphic format. Table 3. Diamondhead Radnor Artificial Reef, preconstruction sea turtle sighting data. Sightings observed in September 2009 are shaded. Date Vessel Position Species Life Stage Bearing/ Distance At/Below Surface 4/24/09 N Caretta caretta Adult 300m SE At W /24/09 N Caretta caretta Adult 200m E At W /18/09 No sightings 9/1/09 No sightings 9/16/09 No sightings Singer Island Erosion Control Project Transect 7. The surface weather conditions were mostly sunny with 10 mph southeast winds. Sea surface had a light chop with wind waves of 1-2 feet. Underwater visibility was very good at 20 feet. Sea surface temperature was 27.9 o C and conditions were deemed acceptable for survey. Survey started at 52 and ended at No sea turtles were sighted during this transect. Transect 8. The surface weather conditions were mostly sunny with 10 mph southeast winds. Sea surface had a light chop with wind waves of 1-2 feet. Underwater visibility was very good at 20 feet. Sea surface temperature was 27.9 o C and conditions were deemed acceptable for survey. Survey started at 1226 and ended at No sea turtles were sighted during this transect. Transect 9. The surface weather conditions were mostly sunny with 10 mph southeast winds. Sea surface had a light chop with wind waves of 1-2 feet. Underwater visibility was very good at 20 feet. Sea surface temperature was 27.9 o C and conditions were deemed acceptable for survey. Survey started at 1215 and ended at One green turtle was sighted on transect. Details are provided in Tables 4&6. Transect 10. The surface weather conditions were mostly sunny with 10 mph southeast winds. Sea surface had a light chop with wind waves of 1-2 feet. Underwater visibility was very good at 20 feet. Sea surface temperature was 27.9 o C and conditions were deemed acceptable for survey. Survey started at 1220 and ended at No sea turtles were sighted during this transect. During preconstruction transects conducted for this project on September 16, 2009 a total of 3.6 kilometers of transects were conducted in the Singer Island Erosion Control Project project area and 3.6 kilometers of transects were conducted in the Singer Island Erosion Control Project downdrift area. One green turtle was sighted on Transect 9 for a sighting per unit effort of 0.56 green turtles per kilometer transect. No other sea 6

7 turtles were sighted on any of the other project or downdrift area transects. Tables 4&6 and Figures 1-4 and 10- present cumulative sighting data in tabular and graphic format. Table 4. Singer Island Erosion Control Project, preconstruction sea turtle sighting data and sightings per unit effort for each transect. Transects conducted in September 2009 are shaded. Green turtles Green turtle sightings per Loggerheads Loggerhead sightings per Transect # Length Date sighted kilometer/transect sighted kilometer/transect /17/ /17/ /17/08 N/A N/A N/A N/A /17/ /16/ /16/ /16/ /16/ /24/ /24/ /24/ /24/ /18/ /18/ /18/ /18/ /1/ /1/ /1/ /1/ /16/ /16/ /16/ /16/ Control (John D. MacArthur Beach State Park) Transect, Run #1. The surface weather conditions were mostly sunny with southeast winds at 10 knots. Sea surface conditions were light chop with wind waves of less than 2 feet. Underwater visibility was good at feet. Sea surface temperature was 27.8 o C and conditions were deemed acceptable for survey. Survey started at 02 and ended at 20. One green turtle was sighted on transect. Details are provided in Tables 5&6. Transect, Run #2. The surface weather conditions were mostly sunny with southeast winds at 10 knots. Sea surface conditions were light chop with wind waves of less than 2 feet. Underwater visibility was good at 20 feet. Sea surface temperature was 28.2 o C and conditions were deemed acceptable for survey. Survey started at 1302 and ended at One green turtle was sighted on transect. Details are provided in Tables 5&6. Transect 12, Run #1. The surface weather conditions were sunny with north winds at 10 knots. Sea surface conditions were light chop with wind waves of less than 2 feet. Underwater visibility was good at feet. 7

8 Sea surface temperature was 27.9 o C and conditions were deemed acceptable for survey. Survey started at 21 and ended at 38. Two green turtles were sighted on transect. Details are provided in Tables 5&6. Transect 12, Run #2. The surface weather conditions were sunny with north winds at 10 knots. Sea surface conditions were light chop with wind waves of less than 2 feet. Underwater visibility was good at feet. Sea surface temperature was 28.3 o C and conditions were deemed acceptable for survey. Survey started at 1323 and ended at No turtles were sighted on the transect. During preconstruction transects conducted on September 16, 2009, a total of 9.32 kilometers of transects were conducted in the control area. Two green turtles were sighted on Transect for a sighting per unit effort of 0.43 green turtles per kilometer transect. Two green turtles were sighted on Transect 12 for a sighting per unit effort of 0.43 green turtles per kilometer transect. Tables 5&6 and Figures 1-4, 9 present cumulative sighting data in tabular and graphic format. Table 5. John D. MacArthur Beach State Park (Control), preconstruction sea turtle sighting data and sightings per unit effort for each transect. Transects conducted in September 2009 are shaded. Green turtles Green turtle sightings per Loggerheads Loggerhead sightings per Transect # Length Date sighted kilometer/transect sighted kilometer/transect /17/ /17/ /16/ /16/ /24/ /24/ /18/ /18/ /1/ /1/ /16/ /16/ Table 6. Cumulative sea turtle sighting locations for all preconstruction transects conducted. Sightings from September 2009 are shaded. Transect # Date Species Life stage Location 2 6/17/08 Caretta caretta Adult N W /17/08 Caretta caretta Subadult N W /17/08 Chelonia mydas Subadult N W /17/08 Chelonia mydas Juvenile N W /17/08 Chelonia mydas Juvenile N W Distance (m) from transect line At/Below Inshore/Offshore surface 0 N/A Below 10 Pier side Below 60 Ocean side At 0 N/A Below 5 I Below 8

9 6 6/17/08 Chelonia mydas Juvenile Off Tran. 6/17/08 Caretta caretta Subadult Off Tran. 6/17/08 Chelonia mydas Adult Off Tran. 6/17/08 Chelonia mydas Adult Off Tran. 6/17/08 Chelonia mydas Adult 6 9/16/08 Chelonia mydas Juvenile 6 9/16/08 Chelonia mydas Juvenile 9/16/08 Chelonia mydas Juvenile 9/16/08 Chelonia mydas Juvenile 12 9/16/08 Chelonia mydas Juvenile 12 9/16/08 Chelonia mydas Juvenile 9 9/16/08 Chelonia mydas Juvenile 3 4/24/09 Caretta caretta Subadult 4 4/24/09 Caretta caretta Subadult 5 4/24/09 Chelonia mydas Juvenile 6 4/24/09 Chelonia mydas Juvenile 9 4/24/09 Chelonia mydas Juvenile 4/24/09 Chelonia mydas Juvenile 4/24/09 Chelonia mydas Juvenile 4/24/09 Chelonia mydas Juvenile Off Tran 4/24/09 Chelonia mydas Juvenile Art. Reef 4/24/09 Caretta caretta Adult Art. Reef 4/24/09 Caretta caretta Adult 5 6/18/09 Chelonia mydas Juvenile 5 6/18/09 Chelonia mydas Juvenile N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W I At N/A N/A At N/A N/A At N/A N/A At N/A N/A At 9 I At 14 I At 6 I At 2 I At 9 I At 9 I At 1 I Below 6 Ocean Side Below 20 Pier Side At 3 I At 1 O Below 5 I At 5 O Below 5 O At 5 O Below N/A N/A At 300 SE N/A At 200 E N/A At 3 I At 1 O At

10 5 6/18/09 Chelonia mydas Juvenile 6 6/18/09 Chelonia mydas Juvenile 8 6/18/09 Caretta caretta Subadult 8 6/18/09 Chelonia mydas Adult 6/18/09 Chelonia mydas Subadult 6/18/09 Chelonia mydas Adult 6/18/09 Caretta caretta Juvenile 6/18/09 Chelonia mydas Juvenile 6/18/09 Chelonia mydas Juvenile 12 6/18/09 Chelonia mydas Juvenile 12 6/18/09 Chelonia mydas Juvenile 12 6/18/09 Chelonia mydas Juvenile 12 6/18/09 Chelonia mydas Juvenile 12 6/18/09 Chelonia mydas Adult 12 6/18/09 Chelonia mydas Juvenile 12 6/18/09 Chelonia mydas Juvenile 12 6/18/09 Chelonia mydas Juvenile Off Tran 6/18/09 Caretta caretta Subadult Off Tran 6/18/09 Caretta caretta Subadult Off Tran 6/18/09 Chelonia mydas Juvenile Off Tran 6/18/09 Chelonia mydas Adult N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W N W Chelonia mydas Juvenile 5 9/1/09 N W N W N W O At 15 I At 15 I Below 10 O Below 10 I At 15 O Below 5 O Below 10 O Below 5 I Below 2 O At 2 I Below 0 On Line Below 3 I Below 4 O Below 5 O Below 3 O Below 3 O Below NA NA At NA NA At NA NA At NA NA Below 5 I Below 10 I Below 6 I Below 0 On Line At

11 5 9 N W N W O Below 2 I Below N W N W N W /1/09 Caretta caretta Subadult N W N W N W N W N W N W N W N W N W N W N W N W N W N W /16/09 Chelonia mydas Juvenile N W /16/09 Chelonia mydas Juvenile N W N /16/09 Chelonia mydas Juvenile W N /16/09 Chelonia mydas Juvenile W N /16/09 Chelonia mydas Juvenile W /16/09 Chelonia mydas Juvenile N W O Below 8 O Below 0 On Line Below 3 I Below 1 I At 1 O Below 1 I Below 5 I Below 10 O Below 5 O Below 2 I Below 2 I Below 20 I At 8 I Below 8 I Below 10 I Below 3 I Below 10 I At 15 I At 1 I Below 7 I At 2 I At 10 I At

12 12 9/16/09 Chelonia mydas Juvenile N W I At Figure 1. Cumulative sea turtle sightings, by transect, for all preconstruction transects conducted (sea turtles sighted off transect and sighted at the artificial reef site are not included) Loggerhead Green Sea Turtle Sightings Transect Figure 2. Cumulative sea turtle sightings, by sampling event, for all preconstruction transects conducted Loggerhead Green Sea Turtle Sightings /17/08 9/16/08 4/24/09 6/18/09 9/1/09 9/16/09 Sampling Date 12

13 Figure 3. Cumulative sightings per kilometer/transect, by transect, for all preconstruction transects conducted (sea turtles sighted off transect and sighted at the artificial reef site are not included) Loggerhead Sightings per KM/transect Green Sightings per KM/transect Sightings per KM/transect Transect Figure 4. Cumulative sightings per kilometer/transect, by sampling date, for all preconstruction transects conducted. Sightings per KM/transect Loggerhead Sightings per KM/transect Green Sightings per KM/transect 6/17/08 9/16/08 4/24/09 6/18/09 9/1/09 9/16/09 Sampling Date 13

14 PL-2S Figure 5: Cumulative summary of sea turtle sightings in the vicinity of the Jupiter Carlin Shoreline Protection Project Photo: 2008 R-014 R-015 R-016 R-017 DEP Monument T-018 Sightings Transect Loggerhead Adult / Loggerhead Subadult Loggerhead Juvenile Green Adult / Green Subadult 6/17/2008 Green Juvenile T ,000 1,500 2,000 Feet

15 T-022 Figure 6: Cumulative summary of sea turtle sightings in the vicinity of the Diamondhead Radnor Artificial Reef Complex Photo: 2008 T-023 4/24/2009 4/24/2009 T-024 T-025 DEP Monument Transect Sightings Loggerhead Adult / Loggerhead Subadult Loggerhead Juvenile Green Adult / Green Subadult T-026 Green Juvenile ,000 1,500 2,000 Feet

16 Figure 7: Cumulative summary of sea turtle sightings in the vicinity of the Juno Beach Fishing Pier Photo: 2008 R-030 / 6/17/2008 R-031 4/24/2009 6/17/2008 / / 4/24/2009 / 4/24/2009 DEP Monument T-032 Transect Sightings Loggerhead Adult / Loggerhead Subadult Loggerhead Juvenile Green Adult / Green Subadult Green Juvenile ,000 1,500 2,000 Feet

17 R-047 9/16/20099/16/2008 Figure 8: Cumulative summary of sea turtle sightings in the vicinity of the Juno Beach Shoreline Protection Project downdrift area Photo: 2008 DEP Monument Transect Sightings Loggerhead Adult R-048 4/24/2009 / Loggerhead Subadult Loggerhead Juvenile Green Adult / Green Subadult Green Juvenile ,000 1,500 2,000 Feet R-049 9/16/20099/16/2008 6/17/2008 R-050 6/17/2008 R-051 6/17/2008 4/24/2009

18 4/24/2009 R-052 R-053 / R-054 9/16/2008 9/16/2008 9/16/2008 R-055 Figure 9: Cumulative summary of sea turtle sightings in the vicinity of the John D. MacArthur Beach State Park (control) Photo: 2008 DEP Monument Sightings Transect Loggerhead Adult / Loggerhead Subadult Loggerhead Juvenile Green Adult / Green Subadult Green Juvenile R ,000 1,500 2,000 Feet T-057 / 9/16/20099/16/2008 R-058 4/24/2009 4/24/2009 R-059 4/24/2009 6/17/2008 R-060

19 R-061 Figure 10: Cumulative summary of sea turtle sightings in the vicinity of the Singer Island Erosion Control Project Photo: 2008 R-062 DEP Monument Transect Sightings Loggerhead Adult / Loggerhead Subadult Loggerhead Juvenile Green Adult / Green Subadult Green Juvenile R ,000 1,500 2,000 Feet / R-064 / 6/17/2008 R-065 R-066

20 R-066 Figure : Cumulative summary of sea turtle sightings in the vicinity of the Singer Island Erosion Control Project downdrift area Photo: 2008 DEP Monument R-067 Sightings Transect Loggerhead Adult / Loggerhead Subadult Loggerhead Juvenile R-068 Green Adult / Green Subadult Green Juvenile ,000 1,500 2,000 Feet R-069 9/16/20099/16/2008 4/24/2009 R-070 R-071 R-072