100 Island Challenge Cruise Report Windward Caribbean Nov 6-16, 2016

Transcription

1 1 Island Challenge Cruise Report Windward Caribbean Nov 6-16, 216 Contributing Authors Dr. Stuart Sandin, Scripps Institution of Oceanography Dr. Brian Zgliczynski, Scripps Institution of Oceanography Lindsay Bonito, Scripps Institution of Oceanography Report prepared on 29 November 216 Photo credit: Ralph Pace

2 Expedition Team Ruleo Camacho, Department of Environment, Antigua & Barbuda Amelia Bird, Department of Environment, Antigua & Barbuda Melanie Meijer zu Schlochtern, St. Maarten Nature Foundation Erik Houtepen, St. Eustatius National Parks Foundation (STENAPA) Tadzio Bervoets, Nature Foundation of Sint Maarten Jens Odinga, Saba Bank National Park Andy Estep, Waitt Institute Ramón de León, Reef Support BV, Bonaire Dr. Mark Vermeij, Carmabi Foundation, Curaçao Ralph Pace, Photographer Lindsay Bonito, Scripps Institution of Oceanography Nicole Pedersen, Scripps Institution of Oceanography Dr. Brian Zgliczynski, Scripps Institution of Oceanography Dr. Stuart Sandin, Scripps Institution of Oceanography Collaborators

3 Executive Summary The Waitt Institute and Dr. Stuart Sandin s laboratory at Scripps Institution of Oceanography collaborated to organize an expedition to conduct a rapid scientific assessment of the coral reefs around the windward Caribbean islands, namely Sint Maarten, Sint Eustatius, Saba, Redonda, and a submarine atoll, Saba Bank. To complement these efforts, the expedition was supported by the Government of Antigua and partners in the nearby Dutch-affiliated islands (St Eustatius, Saba, and St Maarten). The collaboration is part of a larger effort to establish a regional scale perspective of coral reef health, investigating how reefs are structured, how they change over time, and how we can better manage them in the face of global change. The research conducted during thiscruise aimed to investigate the independent and interactive effects of oceanography and human activities in affecting the structure and dynamics of coral reef communities. The survey design controls for within-island variables by conducting the core surveys within the same habitat type forereef habitat at 7-15m depth. To assess the benthic and reef fish communities, the GCRMN methodology was utilized in conjunction with large-area photomosaics to quantify the structure and the workings of each coral reef community at 1-2 km intervals surrounding each island. To complement the ecological data colelcted, two sea temperature recorders (HOBO Pro v2 Logger) were deployed around each island. The temperature recorders were programmed to record the seawater temperature at an interval of thirty minutes. We expect to retrieve these recorders and download the temperature record in approximately 2 years. Across the 4 islands and submarine atoll, 65 sites were surveyed. This effort resulted in a total of 325 fish and benthic transects, following the GCRMN guidelines. Additionally 38 photomosaics were imaged: 6 on Redonda, 11 on Sint Eustatius, 11 on Sint Maarten, 8 on Saba, and 2 on the Saba Bank.

4 The Windward Caribbean Islands Figure 1. Map of the windward Caribbean islands surveyed in November, 216. Surveyed islands include Sint Maarten, Sint Eustatius, Saba, Saba Bank, and Redonda.

5 Island Highlights The Lesser Antilles, also known as the Windward Islands, extend in a curve about 5 miles between Puerto Rico and Trinidad. Most of the islands were formed by volcanic activity, and when combines with the Greater Antilles and Lucayan Archipelago, are known as the West Indies. Redonda Island Type: High island; remnant of an ancient extinct volcano Island Size: 1.6 km long and.5 km wide (between 1.6 and 2.6 km 2 ) Population: uninhabited Sint Maarten Island Type: High island Island Size: 34 km 2 Population: ~39, (211 census) Sint Eustatius Island Type: High island, dormant volcano. Island Size: 21 km 2 Population: ~4, (213 data) Saba Island Type: High island, potentially active volcano Island Size: 13 km 2 Population: ~2, (213 data) Saba Bank Island Type: Submarine atoll Size: ~ 22 km² Population: uninhabited

6 1 Island Challenge Description: This research initiative employs novel approaches for studying coral reef community dynamics through the application of underwater photomosaic technology. Working with colleagues from the University of Miami, we have built a camera system that allows us to capture images of large swaths of the reef surface. Further, by revisiting exact locations multiple times and replicating photography, we have an unprecedented opportunity to track the dynamics of corals and algae. Particularly, with advanced image analysis we can track how a reef community changes, addressing questions of coral growth, death, and competition that are currently unresolved. We have field-trialed this photomosaic equipment and are developing a reliable image analysis protocol. We are now poised to apply this tool to generate the large-scale data of reef community dynamics that have, to date, been unavailable. Further, by combining these image-based data with reliable information about the composition of the fish community, the general oceanography, and the human situation of each location, we can begin to elucidate the conditions that are more (or less) conducive to the maintenance of growing and so-called healthy coral reefs. Application to the Windward Caribbean: By linking the fates of these reefs to the oceanographic conditions and to the local activities of people, we will be able to start understanding cause-and- effect pathways for reef change. Given that local-scale marine managers consistently seek information on the state of their coral reef, looking for comparisons to help guide local management. Further, by making the data that describe each reef readily available and easy to visualize, there is a terrific opportunity to increase the dialogue between the science and management communities, as well as independently among the managers looking for tangible information to improve their self-management. By working side-by- side with regional managers and partners in local NGOs (e.g., the Nature Conservancy, Conservation International), we will expand the scientific insights into the state and future of their reef areas. For more information, visit

7 Survey Metadata Table 1. Sites surveyed to assess and monitor the fish and benthic communities (GCRMN) and collect photomosaic imagery (Mosaic). Project Island Site ID Latitude Longitude Local Name GCRMN Redonda RED_ GCRMN Redonda RED_ GCRMN Redonda RED_ GCRMN Redonda RED_ GCRMN Redonda RED_ GCRMN Redonda RED_ GCRMN Redonda RED_ GCRMN Redonda RED_ Mosaic Redonda RED_ Mosaic Redonda RED_ Mosaic Redonda RED_ Mosaic Redonda RED_ Mosaic Redonda RED_ Mosaic Redonda RED_ GCRMN Saba SBB_ GCRMN Saba SBB_ GCRMN Saba SBB_ GCRMN Saba SBB_ GCRMN Saba SBB_ GCRMN Saba SBB_6B GCRMN Saba SBB_ GCRMN Saba SBB_ GCRMN Saba SBB_A GCRMN Saba SBB_B GCRMN Saba SBB_C GCRMN Saba SBB_D GCRMN Saba SBB_E GCRMN Saba SBB_G Mosaic Saba SBB_ Mosaic Saba SBB_ Mosaic Saba SBB_ Mosaic Saba SBB_ Mosaic Saba SBB_6B Mosaic Saba SBB_ Mosaic Saba SBB_

8 Project Island Site ID Latitude Longitude Local Name Mosaic Saba SBB_8B GCRMN Saba Bank SBB_ GCRMN Saba Bank SBB_ GCRMN Saba Bank SBB_ Mosaic Saba Bank SBB_ Mosaic Saba Bank SBB_ GCRMN St Eustatius STE_ GCRMN St Eustatius STE_ GCRMN St Eustatius STE_ Barracuda Reef GCRMN St Eustatius STE_ Safety First GCRMN St Eustatius STE_ Mushroom Gardens GCRMN St Eustatius STE_ Five Fingers GCRMN St Eustatius STE_ GCRMN St Eustatius STE_ GCRMN St Eustatius STE_ GCRMN St Eustatius STE_ GCRMN St Eustatius STE_ GCRMN St Eustatius STE_ GCRMN St Eustatius STE_ GCRMN St Eustatius STE_ GCRMN St Eustatius STE_ GCRMN St Eustatius STE_ GCRMN St Eustatius STE_ GCRMN St Eustatius STE_ GCRMN St Eustatius STE_ GCRMN St Eustatius STE_ Mosaic St Eustatius STE_ Mosaic St Eustatius STE_ Double Wreck Mosaic St Eustatius STE_ Safety First Mosaic St Eustatius STE_ Mosaic St Eustatius STE_ Mosaic St Eustatius STE_ Mosaic St Eustatius STE_ Mosaic St Eustatius STE_ Mosaic St Eustatius STE_ Mosaic St Eustatius STE_ GCRMN St Maarten STM_ Pelican Reef N GCRMN St Maarten STM_ Pelican Reef S GCRMN St Maarten STM_ Molly Beday

9 Project Island Site ID Latitude Longitude Local Name GCRMN St Maarten STM_ Mike's Maze W GCRMN St Maarten STM_ Coralita GCRMN St Maarten STM_ Fishbowl GCRMN St Maarten STM_ GCRMN St Maarten STM_ Long Bay SE GCRMN St Maarten STM_ Long Bay NW GCRMN St Maarten STM_ Gregory GCRMN St Maarten STM_ Moonscape GCRMN St Maarten STM_ Frenchman GCRMN St Maarten STM_ Hen & Chicks E GCRMN St Maarten STM_ GCRMN St Maarten STM_ GCRMN St Maarten STM_ GCRMN St Maarten STM_ GCRMN St Maarten STM_ Mosaic St Maarten STM_ Cow & Calf Mosaic St Maarten STM_ Hen & Chicks Mosaic St Maarten STM_ Molly Beday Mosaic St Maarten STM_ Mike's Maze E Mosaic St Maarten STM_ Proselyte Reef Mosaic St Maarten STM_ Fishbowl Mosaic St Maarten STM_ The Bridge Mosaic St Maarten STM_ Mosaic St Maarten STM_ Mosaic St Maarten STM_

10 Survey Methods Fish & Macro-Invertebrate Surveys Fish Assemblage Survey Methods Estimates of fish abundance and biomass were completed using methods consistent with the Global Coral Reef Monitoring Network - Caribbean (GCRMN) guidelines for ecological monitoring. In summary, All fish present (of all species) are counted and sized within a belt transect (3m length x 2m width), with the survey time limited to approximately 6 minutes per transect. At each site, at least 5 transects are surveyed and the data are pooled to provide an average estimate of the density and size structure of all fishes at the site. Fish are classified by size to the nearest 5cm bin. Key Macro-Invertebrate Survey Methods The densities of the long-spined sea urchin (Diadema antillarum), other sea urchins, and all sea cucumbers were recorded in situ by the fish diver. Within 3 of the benthic transect lines, the diver counted invertebrates in the first 1m along the transect, within a 2m wide belt, giving a total area of 6m 2. Benthic Surveys Benthic Survey Methods Similar to the fish survey methods, Benthic communities were characterized using a photoquadrat method, consistent with the Global Coral Reef Monitoring Network - Caribbean (GCRMN) guidelines for ecological monitoring. Digital photographs of the reef surface were taken in standardized quadrat areas (.9m x.6m). Photographs are taken along each of the 5 transect lines set for counting fish, with 15 images captured per 3m transect line (i.e., one image taken at every 2m on the transect tape). In total,

11 75 benthic photographs were collected at each site (5 transect lines x 15 photographs per line). Images will be analyzed by overlaying 25 random points and identifying each organism or habitat feature associated with each point to the finest level of resolution possible (genus level for hard and soft corals, functional group for algal turfs and crustose coralline algae, and species level for macroalgae and macroinvertebrates when possible). Photoquadrat images will be analyzed for coral disease as well, in addition to in situ presence/absence surveys of disease within the transects. Coral recruitment was data in situ, with the goal of estimating the density of young corals that are likely to contribute to the next generation of adult corals on the reef. Coral recruits are defined operationally for this assessment as any stony coral that is greater than.5 cm and up to 4. cm. Estimates of coral recruit density were recorded from replicate 25cm x 25cm (625 cm 2 ) quadrats. A total of 3 quadrats were surveyed along each transect used for benthic and fish surveys. The coral recruit quadrats will be placed at 1-meter intervals along the transect line, resulting in a total of 15 quadrats surveys per site (5 transect lines x 3 quadrats per line. Within each quadrat, each stony coral within the target size range (.5-4. cm) were recorded to the finest taxonomic level possible (family, genus, or species). Additionally, in each coral recruitment quadrat, average turf height was also measured four times in the quadrat. Benthic Photomosaic Survey Methods To complement the transect-based benthic surveys, benthic photomosaics were completed to collect a permanent record of reef habitat on a larger scale (1m 2 ). The benthic photomosaic system consists of a diver operating a camera system including dual SLR cameras and video camera mounted to a custom frame. The first still camera is setup to use a wide-angle 18 mm focal length lens to sure high overlap among adjacent images while the second still camera uses a 55 mm focal length lens to capture images with sub-cm resolution. The high-resolution wide-angle video camera serves as a backup in the event that images from the still cameras are compromised. To obtain the large image covering 1m x1m the diver operating the camera system swims a gridded pattern approximately 1.5 m above the benthos recording images at 1

12 sec intervals throughout the plot. A pair of lasers is mounted within the frame of the 55 mm camera to provide scale in the high-resolution imagery. Images are later stitched together analytically using custom algorithms to create a single image file representative of the 1m 2 plot. Figure 2. Photomosaic Data Collection Method. Each mosaic is stitched together from ~2 photos acquired by swimming back and forth over the reef in the pattern on the left. Figure 3. Photomosaic Processing Method. Once stitched, each mosaic is ecologically post-processed by tracing individual coral colonies and algae species of interest. Once individual colonies are traced and identified (E), data is exported and run through custom algorithms to evaluate both standard metrics including percent coral cover and more complex spatial statistics.

13 Summary Findings Figure 4. Sites surveyed during the November 216 expedition.

14 Fish Survey Results Fish Abundance Figure 5. Fish abundance (individuals per m 2 ) by trophic group in Redonda. Figure 6. Fish abundance (individuals per m 2 ) by trophic group in Saba.

15 Figure 7. Fish abundance (individuals per m 2 ) by trophic group in Saba Bank. Figure 8. Fish abundance (individuals per m 2 ) by trophic group Sint Maarten.

16 Figure 9. Fish abundance (individuals per m 2 ) by trophic group in Sint Eustatius. Figure 1. Fish abundance (individuals per m 2 ) by trophic group across all islands.

17 Table 2. Abundance of fishes by species in Redonda (individuals per m 2 ) and trophic level classifications.

18 Figure 11. Fish biomass (g/m 2 ) by trophic group in Redonda. Figure 12. Fish biomass (g/m 2 ) by trophic group in Saba.

19 Figure 13. Fish biomass (g/m 2 ) by trophic group in Saba Bank. Figure 14. Fish biomass (g/m 2 ) by trophic group in Sint Maarten..

20 Figure 15. Fish biomass (g/m 2 ) by trophic group in Sint Eustatius. Figure 16. Fish biomass (g/m 2 ) by trophic group across all islands.

21 Table 3. Biomass (g/m 2 ) of fishes in Redonda by species and trophic level classifications.

22 Benthic Survey Results Mean Density of Juvenile Corals Mean Density of Juvenile Corals (# per m2) Saba & Saba Bank Mean Density of Juvenile Corals (# per m2) Sint Eustatius

23 Mean Density of Juvenile Corals (# per m2) Sint Maarten Mean Density of Juvenile Corals (# per m2) Redonda RED_ RED_1 RED_2 RED_3 RED_4 RED_5 RED_6 RED_7 Figures Mean and standard error of density of juvenile stony corals per site (number of individuals per m 2 ). Survey site covers an area of 56.25m 2.

24 Mean Density of Juvenile Corals (indivduals / m 2 ) Redonda Saba Saba Bank St Eustatius St Maarten Figure 21. Mean and standard error of density of juvenile stony corals per island (number of individuals per m 2 ). Island survey area covers 93.75m 2. Total Number of Juvenile Corals Total # of Juvenile Corals (Per 56.25m2) Saba & Saba Bank

25 Total # of Juvenile Corals (Per 56.25m2) Sint Eustatius Total # of Juvenile Corals (Per 56.25m2) Sint Maarten

26 35 Redonda Total # of Juvenile Corals (Per 56.25m2) RED_ RED_1 RED_2 RED_3 RED_4 RED_5 RED_6 RED_7 Figures Total number of individual juvenile stony corals in site survey area (56.25 m 2 ). 35 Total # of Juvenile Corals Redonda Saba Saba Bank St Eustatius St Maarten Figure 26. Total number of individual juvenile stony corals at the island level (survey area m 2 ).

27 Number of Juvenile Corals by Species 35 # of Juveniles RED_ RED_1 RED_2 RED_3 RED_4 RED_5 RED_6 RED_7 SSID SRAD PPOR PAST MDEC MCAV FFRA AGA AAGR Figure 27. Total number of individual juvenile stony corals by species in site survey area (56.25 m 2 ) in Redonda. Coral species: SSID- Siderastrea sidereal; SRAD- Siderastrea radians; PPOR- Porites porites; PAST- Porites asteroids; MDEC- Madracis decactis; MCAV- Montastraea cavernosa; FFRA- Favia fragum; AGA- Agaricia spp.; AAGR- Agaricia agaricites. Mean Diameter of Juvenile Corals Mean Juvenile Size (mm) Saba & Saba Bank

28 Mean Juvenile Size (mm) Sint Eustatius Mean Juvenile Size (mm) Sint Maarten

29 45 4 Redonda Mean Juvenile Size (mm) RED_ RED_1 RED_2 RED_3 RED_4 RED_5 RED_6 RED_7 Figures Mean size (diameter, mm) and standard error of juvenile stony corals in site survey area (56.25 m 2 ) Mean Juvenile Size (mm) Redonda Saba Saba Bank St Eustatius St Maarten Figure 32. Mean size (diameter, mm) and standard error of juvenile stony corals by island (survey area m 2 ).

30 Mean Turf Height Mean Turf Height (mm) Saba & Saba Bank Mean Turf Height (mm) Sint Eustatius

31 Mean Turf Height (mm) Sint Maarten 2 18 Redonda Mean Turf Height (mm) RED_ RED_1 RED_2 RED_3 RED_4 RED_5 RED_6 RED_7 Figures Mean height and standard error (mm) of turf in site survey area (56.25 m 2 ).

32 1 9 Mean Turf Height (mm) Redonda Saba Saba Bank St Eustatius St Maarten Figure 37. Mean height and standard error (mm) of turf by island (survey area m 2 ).

33 Photomosaic Results & Products All mosaic products are available online both on the 1 Island Challenge YouTube Channel and through our public Google Drive. Below are links and URLs where you can find these products. 1 Island Challenge Google Drive Link 1 Island Challenge YouTube Channel Link

34 Sample Photomosaic Island: Sint Maarten Site: SM15 (Mike s Maze E) Date: November 216 Habitat Type: forereef Protection Status: MPA

35 Landscape of the Windward Islands