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conservation

Dr Owen O’Shea visits the Florida Fish and Wildlife Conservation Commission

The ongoing collaboration between the Cape Eleuthera Institute and the Florida Fish and Wildlife Conservation Commission (FWWCC) was recently further endorsed with a visit by Research Associate Dr Owen O’Shea to the FWWCC headquarters in St. Petersburg, Florida. Much of Dr O’Shea’s work on stingray genetics is in collaboration with Dr Liz Wallace, postdoctoral research fellow at the commission and so this trip served as an analytical opportunity for Owen to conduct lab work with Dr Wallace in order to process DNA samples collected over the past 12 months. IMG_4408

This research project is in the final stages of completion, after Owen collected 70 samples from the rare, elusive and recently re-described Caribbean whiptail stingray Styracura schmardae across multiple spatial scales in the central Bahamas. This work is the first of its kind in this species, and will attempt to discern dispersal potential and gene flow across restricted temporal periods, for example, in assessing sibling and parentage relationships, rather than an historical radiation.

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This work is important, because in fragmented habitats, such as The Bahamas, barriers to gene flow and dispersal are realized, particularly among island chains, separated by deep ocean basins. This provides challenges for live bearing fish species, further exacerbated by conservative life histories; so understanding these dynamics and potential migratory corridors will enable us to further discern the importance of these coastal environments.

Coral and Hurricane Matthew

As Hurricane Matthew made contact with the Bahamas in early October, it brought with it many threats of damage and devastation. The Cape Eleuthera Institute (CEI) was extremely fortunate in the sense that Matthew did not hit as hard as expected, but still the storm left its fair share of destruction. Coral reefs offer numerous benefits to ecosystems; one of these being that they can dissipate the power of storm waves generated by hurricanes and therefore lessen the blow of terrestrial damage. However, this absorption of wave energy does not leave the reefs unimpaired. During large storm systems such as hurricanes, corals are susceptible to fragmentation. Fragmentation is a negative effect in the sense that it can cause some stress to the coral, but on the other hand it can be a positive event because some coral species, such as Elkhorn coral (Acropora palmata) and Staghorn coral (Acropora cervicornis) use fragmentation as a form of asexual reproduction. That is, a new colony can grow from a fragment of the parent colony. Scientists across the Caribbean, including here at CEI, are using this method of growth to create coral nurseries which grow fragments to be outplanted onto damaged reefs.

Island School students aid in the monitoring and upkeep of our coral nurseries. In the above photo, students are measuring Staghorn coral (Acropora cervicornis) in order to track its growth rate. (Photo_ Brittany Munson)

As CEI continues to focus its research on the endangered Elkhorn coral (Acropora palmata) in the wild, the Coral Team went out to assess the toll Hurricane Matthew had on our local reefs. As expected, there was a decent amount of fragmentation found at Bamboo Point, where there was a large colony of Elkhorn coral with evidence of recent storm damage. Some fragments seen nearby were due to Hurricane Matthew whereas others were older and likely produced by past events. It is CEI’s hope that the newly-formed fragments will proliferate to form new colonies.

This photo displays some recent fragmentation of Elkhorn coral (Acropora palmata) caused by Hurricane Matthew. This fragmentation occurred at Bamboo Point, a site near the CEI campus. (Photo_ Reilly Edgar)

In addition to fragmentation, hurricanes have been shown to relieve thermal stress. By mixing the water column and bringing water temperatures down, storms can once again restore favorable thermal conditions and allow coral the chance to recover from bleaching events. As climate change continues and sea surface temperatures rise, coral bleaching events have become more prevalent as the coral’s symbiotic zooxanthellae are expelled. Due to a number of stressors including climate change, overfishing and pollution, coral are increasingly vulnerable. Major storm events are beneficial only once in a while, but if there are too many large storms too often it not only makes the environment uninhabitable for corals, but also can permanently damage reefs that are already existing at the upper limits of their stress tolerance.

As the 2016 hurricane season comes to an end, CEI will continue its monitoring and restoration efforts of Eleuthera’s reefs in the hopes that we can continue to enjoy the many benefits they provide!

Investigating bonefish spawning aggregations on Eleuthera, The Bahamas: migrations, predators, and environmental cues

Last year, CEI’s Flats program, along with Georgiana Burruss, CEI Research Assistant, began a three-year study to identify critical bonefish spawning aggregation sites on Eleuthera, The Bahamas. Currently, six spawning aggregation locations have been identified in The Bahamas; one of which is located in South Eleuthera. This study aims to track bonefish populations across Eleuthera to fill this knowledge gap and identify critical habitat for this economically important species. In year one, the team identified a number of potential bonefish spawning migration corridors in North Eleuthera, South Eleuthera, and along the East coast of Eleuthera.  The team deployed 62 VEMCO acoustic receivers to track the movements of 39 tagged fish as they migrated away from known foraging grounds and tidal creeks. Bio-telemetry data indicated potential spawning migration corridors in the North East, South East, and East regions of Eleuthera. In addition, the team was able to track the nighttime movements of spawning aggregations in the South West region of the island. Although, transmitter detections in the North West part of the island were limited, data suggests this may be a result of timing coordinated with spawning-related movements in other regions, indicating that the detections were potentially spawning-related. Interestingly, bonefish tagged in each of the areas were not detected in another region, suggesting these populations are unlikely to mix. Overall, 5 migration corridors have been identified, with data suggesting that there are at least 5 bonefish spawning sites on Eleuthera, although further studies are needed.

Map of five regions dividing Eleuthera into North East (6 tagged fish), North West (6 tagged fish), East (10 tagged fish), South West (4 tagged fish), and South East (13 tagged fish)

Given the success of last year, the bonefish telemetry project officially kicked off its second year of data collection to answer the following questions:

  1. Where are bonefish forming spawning aggregations in the 5 regions of interest on Eleuthera?
  2. How do abiotic factors (season, moon phase, temperature, current, tide, etc.) influence bonefish spawning migrations in South Eleuthera?
  3. What is the energetic cost of spawning migrations?
  4. How do predators interact with the bonefish spawning aggregation?

Two VEMCO positioning arrays were deployed to assess the broad and fine scale spawning migration movements of bonefish in Eleuthera. 42 receivers in the broad scale array were concentrated around zones of interest in each region (identified from last year’s study) to further the understanding of bonefish spawning migrations and staging areas. This increase in coverage combined with manual tracking and visual observations should provide further evidence and confirm our previously identified sites of interests as critical spawning areas. Transmitters will be implanted in 30 bonefish at strategic locations around Eleuthera allowing for the fine scale movements of these fish to be collected. Additionally, these fish will add to the existing 39 bonefish tagged last year to provide unprecedented data on these economically important species. By simultaneously tracking bonefish from several areas of Eleuthera, we can better determine which environmental cues bonefish use to form spawning aggregations, such as moon phase and tides.

VEMCO receivers are attached to cinder blocks with rebar posts. This receiver has a SYNC tag positioned above it, allowing for triangulation of position with other nearby receivers and allowing for the fine scale movement of bonefish to be assessed.

At the previously identified spawning aggregation site of interest in South Eleuthera, 31 receivers were placed in an  overlapping fine-scale array to track the  movements of the bonefish aggregation on an almost continuous basis. This array will allow the team to answer questions related to: how abiotic factors (current, moon phase, seasonality, tide) influence bonefish spawning, how predators interact with the aggregation, understanding the energy expenditure of bonefish when migrating to their spawning site, and potentially the physical act of spawning which is yet to be described. Furthermore, the fine-scale array will fill critical knowledge gaps regarding the diel movements of tagged predatory species, such as great barracuda,Sphyraena barracuda, and blacktip shark, Carcharhinus limbatus.  In addition to the basic positional transmitters being deployed, the team will be deploying 20 acoustic transmitters fitted with accelerometer sensors to determine energy expenditure of bonefish during spawning as well as 20 acoustic tags in predatory species to assess predator interactions with the bonefish spawning aggregation.  Collectively, findings from this study will be used to develop a management and conservation framework for bonefish and predatory species of surrounding Eleuthera, The Bahamas.

Georgiana Burruss makes an incision for internal implantation of an acoustic tag in a bonefish captured at Half Sound.

A bonefish recently implanted with an internal acoustic tag also receives an external spaghetti tag in order to identify it in the event that this fish is recaptured.

This project is being conducted in partnership with Fisheries Conservation Foundation (FCF) and funded by the Hutchins Family Foundation. Georgiana Burruss is conducting this study as a MSc. thesis at Michigan State University. This year, the team is supported by visiting researchers from FCF, Illinois Natural History SurveyFlorida Institute of Technology, and Florida Fish and Wildlife Conservation CommissionCocoloba ToursFishbone Tours, and the Rainbow Inn have provided support in the form of lodging and guiding. For more information regarding this project, please contact Georgiana Burruss (georgianaburruss@islandschool.org).

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CEI shark team pulls in rare catch!

On Wednesday, August 31, 2016, the CEI Shark Research and Conservation Team caught and sampled a huge 258 cm male lemon shark (Negaprion brevirostris). This thrilling capture was made while conducting a longline survey off of Cape Eleuthera, Bahamas to establish a dataset about the abundance and size of different coastal shark species in south Eleuthera.  Although a wide variety of sharks can be found around the Bahamas, and there are many known lemon shark nurseries, mature lemon sharks are not commonly seen near south Eleuthera. The information collected from this rare catch can be used to trace the lineage of lemon shark populations found throughout the Bahamas, which can ultimately help influence future shark conservation and management initiatives.

Research Tech Maggie Winchester holds a 258cm long lemon shark in tonic immobility.  This allows the team to take measurements and samples, as well as tag the animal in a manner that is safe for both the shark and the researchers

Lemon sharks are a large species of coastal shark that can reach up to 3.5 m in length. They can be identified by their pale brown or olive coloring, and their two equally sized dorsal fins.  Lemon sharks are listed as Near Threatened and their position at the top of the food chain makes them a valuable species for the local ecosystems. However, there is a limited amount of data on these adult sharks in this area which makes this catch all the more exciting. The Bimini Biological Field Station fills this knowledge gap by reconstructing adult male genetic information using the samples from the more abundant juveniles. Now we can include the data collected from this individual to create a more complete understanding of the local lemon shark population.

The team holds the lemon shark in tonic immobility so Dr. Heather Marshall can take a blood sample

During the workup procedure, the lemon shark was measured to obtain information about its size, age, and sex, which can then be added to the data collected by CEI to show the dynamics of the local populations of sharks. The size of the shark was recorded by taking three specific measurements of its body. The team also collected a tissue sample, which will be used to build up a long term genetic record of the shark populations around Eleuthera. After all measurements and samples were collected, the lemon shark was tagged using a dart tag and a dorsal tag. These tags are used for identification purposes, allowing the research team to recognize a recapture. Following the workup procedure, the lemon shark was released in great condition and everybody was left in awe as it swam away.

The team is preparing to release the lemon shark by removing the hook so the researchers can effectively release the shark quickly and safely

The team watches the lemon shark swim away after a successful capture and release

CEI and SECORE document critically endangered coral spawning

SECORE (SExual COral REproduction) International arrived at the Cape Eleuthera Institute last month for a week of research focused on coral spawning. SECORE is a non-profit organization dedicated to the restoration of coral reefs using wild coral spawn, lab-based fertilization and breeding techniques and outplanting methods. Led by Dr. Dirk Peterson (founder and CEO), Christoph Haacke (BioDivers, Germany), Mark Schick (Shedd Aquarium, USA), and Mitch Carl (Henry Doorly Zoo and Aquarium, USA), the SECORE team believes that in order to rehabilitate degraded reefs, increasing coral survival, diversity and abundance through lab-based breeding techniques is essential. Dr. Peterson began his innovative coral breeding techniques in 2002 by fertilizing coral spawn and raising larvae in a lab. The coral restoration community took notice of his successes, and SECORE has since led projects in locations such as Guam, Mexico, Curaçao, and The Philippines. With reversing the decline of coral reefs a national priority in The Bahamas, SECORE aims to bring its expertise here to Eleuthera, in partnership with CEI, to help with rehabilitation and restoration efforts. image1

The focus of SECORE’s work in Eleuthera is Elkhorn coral (Acropora palmata), a critically endangered species. Elkhorn coral spawning has rarely been documented in The Bahamas, but is known to occur elsewhere in the Caribbean after sunset, during the days following August full moons. As the week-long workshop began, SECORE aimed its efforts on diving after sunset in high-density areas of Elkhorn coral in hopes of not only documenting the exact timing of the annual spawning event, but also collecting egg and sperm for fertilization back in the lab. To the group’s delight, the timing was perfect. SECORE and CEI documented Elkhorn coral spawning in Eleuthera for the first time! In addition, SECORE collected approximately one to two hundred thousand eggs from four different coral colonies that spawned simultaneously.

Various brooding corals collected to obtain coral larvae. The species are Undaria humilis and U. agaricites.

To ensure ample genetic diversity among corals fertilized in the lab, SECORE collects eggs and sperm from multiple Elkhorn coral  colonies. This diversity is  essential for the survival of this endangered species, which can be threatened by a genetic bottleneck as populations decline. Once SECORE induced fertilization, larvae were placed in a breeding chamber for development. Live rock similar to that upon which wild coral larvae attach on natural reefs was introduced to the tanks, allowing lab-reared corals to become established as would their wild counterparts. CEI’s and SECORE’s collaborative goal is to give juvenile corals a head-start by providing a predator-free, controlled environment where survival is enhanced during critical early growth stages. Once juveniles have survived in the lab beyond those critical early stages, they will be strategically out-planted onto local reefs in an effort to rehabilitate areas where Elkhorn corals are in decline.

Coral reproduction workshop led by Dr. Dirk Peterson from SECORE International. Here, various scientists and conservationists are collecting brooding coral larvae from individual tanks to be observed under the microscope!

Many thanks to SECORE International for educating scientists, students and conservationists on site during the visit, and for its continued work to rehabilitate populations of essential, reef-building corals not only in Eleuthera, but throughout the Caribbean.