Rapid Reef Assessments in South Eleuthera

On January 29th, visitors Lindy Knowles of the Bahamas National Trust and Hayley Jo Carr of Stuart Cove’s arrived in Eleuthera from Nassau to assist in the surveying of reefs in South Eleuthera for the Atlantic and Gulf Rapid Reef Assessment (AGRRA). AGRRA supports coral reef conservation and empowers those who protect these diverse ecosystems by distributing data, research and educational materials that support this mission. Using standardized assessment protocols designed by AGGRA, valuable regional surveys of coral reef health are produced and accessed in an online database. Surveys incorporate coral, benthic, and fish species. 

Candice Brittain beginning a 30 meter long fish survey (Photo by Hayley Jo Carr)

Candice Brittain beginning a 30 meter long fish survey (Photo by Hayley Jo Carr)

While AGRRA surveys around the Caribbean have been ongoing for several years, and have resulted in many publications and regional coral reef report cards, no assessment of reefs in Eleuthera had previously been conducted. CEI’s Candice Brittain (Director of Outreach and Partnerships), trained in fish surveying, and Drew Hitchner (Coral Research Technician), trained in coral surveying, joined Lindy and Hayley, both trained in benthic surveying, for a full week dedicated to updating knowledge regarding the state and health of Eleuthera reefs. The team traveled to local dive sites around the Cape, as well as randomly selected fore and crest reef areas on the eastern side of the island. While some surveying had been completed over the past few months, this one week tripled the data set for South Eleuthera reefs.

Drew Hitchner conducting measurements during a coral survey (photo by Hayley Jo Carr)

Drew Hitchner conducting measurements during a coral survey (photo by Hayley Jo Carr)

The information collected by these surveys will contribute towards filling the knowledge gap of some of the previously data deficient Eleuthera reefs, and support the understanding of the status of reefs in The Bahamas currently. The standardized AGRRA data can be used by decision makers to make informed decisions regarding marine resource management. 

Special thanks to the Bahamas National Trust, the Perry Institute for Marine Science, and Stuart’s Cove Dive Bahamas for their contribution in this effort as well as Lindy, Hayley, Candice, and Drew for their time and work in improving essential Eleuthera coral reef statistics. 

The South Eleuthera AGRRA team. (Left to right) Drew Hitchner (CEI), Hayley Jo Carr (Stuart's Cove), Candice Brittain (CEI), Lindy Knowles (Bahamas National Trust) (Photo by Hayley Jo Carr)

The South Eleuthera AGRRA team. (Left to right) Drew Hitchner (CEI), Hayley Jo Carr (Stuart's Cove), Candice Brittain (CEI), Lindy Knowles (Bahamas National Trust) (Photo by Hayley Jo Carr)

 

 

Taking The Bull By The Horns: Another Shark Successfully Tagged

As 2017 gets underway, CEI welcomes a whole host of new interns and research technicians across the institute. With the start of the spring semester, the bull shark (Carcharhinus leucas) tagging project enters its fourth year. The shark team began the year with the capture of a 265cm total length female in the Cape Eleuthera Marina. On the 25th of January, the team used the poly ball method to hook and draw the shark to the research vessel for data collection. A satellite tag and an internal acoustic tag were installed and various measurements and tissue samples were collected. These tags will relay location data to CEI, which will then be used to assess habitat use among multiple spatial scales in order to uncover patterns in residency and associations with specific environments.

The bull shark is secured to the side of the boat whilst being held in a state of tonic immobility

The bull shark is secured to the side of the boat whilst being held in a state of tonic immobility

Sharks are highly threatened, with overall populations now less than 10% of what they were before the industrial revolution. Sources of the decline include the finning industry as well as bycatch in various commercial fisheries. The bull shark specifically, is classified as near threatened by the IUCN, therefore a better understanding of its habitat association is essential for successful conservation legislation. One of the greatest challenges regarding the conservation of such a large, highly mobile fish is that protection laws substantially differ between countries and jurisdictions. While these sharks are protected in Bahamian waters, we are hoping to develop more comprehensive frameworks for the protection of this, and other species of shark that are threatened.

Dr. Owen O'shea surgically implants an internal acoustic tag

Dr. Owen O'shea surgically implants an internal acoustic tag

The CEI Elasmobranch Research and Conservation Program has now tracked eight female bull sharks in an attempt to discern patterns in this species’ habitat use. CEI hope to tag more individuals in the upcoming months to better inform conservation management. By tracking the location of these sharks, the research team can determine any trends in the movement as the bull sharks leave thesanctuary of the Bahamian waters and use this data to encourage protective legislation in other areas.

After these females leave Cape Eleuthera around April, we will expect to see the same individuals (and typically a few new females) back in October later this year. You can follow more updates regarding this and our other exciting research on Facebook and Instagram.

Island School alum, CEI Grad Student featured on Cal Bears site

Mackey leads a deep sea trip with Island school students Mackey Violich, a former student from fall 2006, and now a graduate student at the Cape Eleuthera Institute through Florida State University, has been featured on the Cal Bear website. At the University of California Berkeley, Mackey Violich spent 4 years playing division one lacrosse and double majoring in Conservation Resources Studies and Environmental Economics. She is currently working on her masters focusing on the deep-sea ecosystem in the Exuma Sound.

Read about her here!

 

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.

IMG_4414

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.

Prey discrimination in yellow rays: project update

In the last month, Research Technician Maggie Winchester began behavioral trials of yellow rays (Urobatis jamaicensis) as part of her independent project, under the supervision of Dr. Barbara Wueringer of James Cook University, Australia, and Dr. Owen O'Shea of the Cape Eleuthera Institute (CEI). This project aims to address the capacity of the electric sense utilized by all elasmobranchs, as it pertains to their foraging strategy. Specifically, Maggie and the team using experimental manipulations to assess to what extent prey type can be ‘discriminated’ by isolating electric sensory mechanisms alone.

Yellow ray close up

The yellow ray is one of the most ubiquitous and commonly encountered elasmobranchs throughout the Caribbean region and is a regular visitor to the shelf and patch reefs adjacent to CEI. It is a small-bodied benthic ray that lives in seemingly mixed sex aggregations and is very easy to catch in shallow water with two dip nets by snorkeler. So far, the team has successfully captured and transported 19 rays to the wet lab at CEI, where they have all undergone behavioral trials, and been successfully returned to their capture sites after 24-hours observation.

A yellow ray in one of our wet lab holding tanks awaiting trails

During the experimental trials, individual rays are presented with two concealed prey types that are known to be part of their diet based on a study by CEI currently in review for publication. These two prey choices are concealed in agar, masking visual, chemical and gustation cues and allowing for detection solely through electro-sensory means.

This work will allow a clearer and more concise evaluation on the specific role the ampullae-lorenzini have in discriminating a specific type of prey, and raises questions on whether these rays actively choose one prey type over another.