High on top of the Bahamian crest is a queen conch—an iconic representation of how truly integrated marine ecosystems are to Caribbean culture. Queen conch (Strombus gigas) is a large gastropod native to the Caribbean and has been a staple in the Bahamian diet for centuries. Unfortunately, the overfishing of conch has caused massive declines in populations, and conservation efforts are greatly needed to promote a healthy and sustainable conch fishery in the Bahamas.
In fisherman lore around the Bahamas it is said to be bad luck to throw knocked conch into the water, as it will scare away living conch—thus, huge conch middens are often found onshore. But, some conch are still tossed overboard at sea, and it is thought this may also be affecting conch populations. The Sustainable Fisheries team, here at the Cape Eleuthera Institute (CEI), is testing avoidance behavior from conch with help of several Island School students. The main question is- do conch flee upon seeing/smelling an injured or dead conspecific, and if so, what sort of cue is triggering movement?
So far 40 trials have been conducted, and CEI’s Claire Thomas, Program Manager for Sustainable Fisheries, will be presenting the preliminary results at the Bahamas National Trust Natural History Conference in Nassau this week. As we conduct more trials and gain more insight into potential conch avoidance behavior, there may be implications for new management strategies to better protect this important species—stay tuned for results!
Nassau grouper is an economically important species in The Bahamas. Due to heavy fishing pressure, there have been marked decreases in their population sizes, especially noticeable during their spawning season. The spawning season takes place during the winter months, from December to the end of February, and the aggregations occur during the full moon. Dr. Kristine Stump from the Shedd Aquarium has been monitoring Nassau grouper in The Bahamas to track their movements to spawning aggregations, as well as to quantify the number of Nassau grouper at these historical spawning sites.
This January, the Shedd Aquarium research vessel, The Coral Reef II, travelled to Long Island, to historical spawning sites, with a representative of The Cape Eleuthera Institute on board, to assist Dr. Stump with her research. Throughout the week-long journey, the researchers on board performed dive surveys to quantify spawning stock size at one specific site. Unfortunately, very few Nassau grouper were aggregating at the site during the times of the surveys; at most 20 were noted on one survey. Illegal fishing was occurring at the time the vessel reached the site, which could explain the decreased abundance of the grouper. Poor weather conditions prevented the researchers from performing surveys on the night of the full moon, so it is unclear if numbers increased during the spawning event. Continue reading →
Last week, researchers from The Cape Eleuthera Institute traveled to Abaco for the 7th Biennial Abaco Science Alliance Conference (ASAC) hosted by Friends of the Environment. Over the course of two days, posters and presentations alike highlighted research findings in natural history and environmental science in The Bahamas. Drawing a diverse audience with scientists from The Bahamas to as far as Canada, local community members and high school students from Abaco, the conference provided a forum for sharing scientific knowledge on the diverse ecosystems of The Bahamas.
Dr. Owen O’Shea, Research Associate for the Shark Research and Conservation Program, gave an engaging presentation on the ongoing stingray research project at CEI and ecosystem-driven approaches to conservation. Candice Brittain, Applied Scientific Research Department Head, spoke about the recent assessment of the queen conch nursery ground in South Eleuthera. Her presentation was followed by a workshop on conservation of queen conch in The Bahamas, led by the Bahamas National Trust. Georgie Burruss, Research Assistant for the Flats Ecology and Conservation Program, presented new findings on marine debris in the Exuma Sound and plastic ingestion by pelagic sportfish. She also gave a talk on studies conducted by the Flats Program that have aided in developing the Best Handling Practices for bonefish and protection of critical bonefish habitat. Finally, Eric Schneider, graduate student at University of Illinois Urbana-Champaign, presented research he conducted at CEI on temperature change effects on juvenile and adult schoolmaster snapper.
ASAC provided a unique opportunity for networking between the local community, students, and researchers for sharing knowledge on ecosystems across The Bahamas. Researchers from CEI look forward to attending ASAC in 2018!
This semester, the Sustainable Fisheries Team has been surveying the waters of South Eleuthera in search of juvenile queen conch. In 1993, South Eleuthera had the largest surveyed juvenile conch nursery in The Bahamas.
On the seashores of The Bahamas, it is common to see conch middens, or large piles of discarded conch shells. When fishermen return from their fishing trips, they take the fleshy meat from inside the shell and then throw that shell away. Recent conch shell midden data shows a significant increase in the harvest of juveniles. In South Eleuthera, 49.2% of the conch shells in one local midden are characterized as juveniles (lack of a flared lip).There has also been a significant decline in the number of adult conch mating aggregations in South Eleuthera.
Understanding if there is still an important juvenile conch nursery in South Eleuthera will help determine the current status of this economically and ecologically important species. Using methods created by researchers at the Shedd Aquarium, snorkelers are towed behind a boat on a manta-tow board with a Gopro attached. Images are taken continuously to document the number of conch, life stage and habitat type throughout the tow. The images are then pieced together to create a visual map of the tow. This methodology allows a rapid, accurate assessment of conch, and also documents the habitat types conch are being found in. The depths and temperature are also recorded for each tow.
During many of the surveys, only a small number of queen conch were observed, and in some tows no conch were found. But, recently, a high density of juvenile queen conch was discovered. These findings could help inform future sustainable harvesting strategies and conservation management for queen conch.
Our partner, the Shedd Aquarium, have a research team that is currently conducting further research to investigate the dispersal of conch eggs throughout the oceans currents. This further research is vital for understanding the full life cycle of queen conch and the locations of important habitats for this species.
We recommend that you only harvest conch with a fully flared lip with at least a 15mm thickness. This is when conch is considered sexually mature and can reproduce. It is important that species are able to reproduce before they are harvested, otherwise populations will most likely crash and possibly become endangered or even extinct.
Last Thursday was The Island School Research Symposium! It is a highlight of Parent’s Week, and a time for parents to hear about the good work being done by their sons and daughters. Throughout the semester, The Island School students have collaborated with CEI researchers, contributing to ongoing research projects. They have been studying various ecosystems around Eleuthera, including inland ponds, the pelagic zone, the deep sea, shallow water sandbars, and tidal creeks .
In all, nine projects were presented, and Dr. Craig Dahlgren, Senior Research Scientist for the Bahamas National Trust, concluded the event with a talk on the state of coral reefs in The Bahamas. All nine projects are being featured on our Instagram (@CEIBahamas) and Facebook pages, so please check them out for more details on the amazing research done this semester!
Last weekend, programs from the Cape Eleuthera Institute, including the Reef Ecology and Restoration Team, Sustainable Fisheries Team, Sea Turtle Team, and Aquaponics Program travelled to Governor’s Harbour Homecoming to spread the word about each of their fields.
Many people showed great interest in the lionfish and aquaponics displays. They were amazed at the use of plants to filter the fish waste out of water holding tilapia in the aquaponics system, while others who had never tried lionfish fritters are now converts!
The Sea Turtle Team and Sustainable Fisheries Team also educated the attendees about the protection of sea turtles through some fun word games, and the life stages of conch through a display with varying sizes of shells, ranging from juveniles to adults.
On the night of Halloween, the CEI team put on their lionfish costumes and travelled to the Spooktacular event at the Leon Levy Native Plant Reserve in Governor’s Harbour. The team continued to spread the word about the lionfish invasion with spooky red lights illuminating a tank showcasing a live lionfish, and dyed blue, green and red fritters.
Batman, Spiderman, witches and several zombies came to view the illuminated invasive lionfish, and were served the spooky and tasty lionfish fritters. Those who had never tasted lionfish before enjoyed the delicious fish and gave great feedback, stating they were tastier than conch fritters, even when they were green inside! Next weekend the team will be setting up a booth at the Governor’s Harbour Homecoming, and hope to continue our long term goal of seeing lionfish not just at outreach events, but permanently on restaurant menus throughout The Bahamas.
On October 10, the CEI team headed to Wemyss Bight Homecoming to spread the word about the lionfish invasion. The team was armed with a large batch of lionfish fritters to give everyone the chance to taste these invaders. The booth grabbed lots of attention from a large range of age groups, enticed by the live lionfish in a tank and the smell from the fritters! Most people had the perception that lionfish were poisonous and wanted to know if it was safe to try the fritters. The misconception that lionfish are poisonous is a large problem facing the management of the invasion, as it reduces the demand for lionfish!
After educating people that lionfish were in fact venomous (therefore the meat contained no toxins) and extremely tasty, the fritters were a hit! Earrings made from lionfish fins were also on show, enabling us to increase awareness surrounding the lionfish jewellery market, another great way to increase incentive for the removal of the invaders from reefs. The team will be continuing to attend events like these in the future, passing on knowledge and changing people’s opinions on lionfish.
The Slayer Campaign has been a huge success at the Cape Eleuthera Institute this year, and we’re well on our way to setting a new record for the total catch this season. The initiative provides the perfect opportunity for local fishermen, while also removing invasive lionfish from the reefs. Here at CEI we always make sure the fillets are passed on to our kitchen staff so that the taste can be shared throughout the community.
The true spearing skills of our local fishermen were recently highlighted by the size of one lionfish in particular, whose total length reached a rather impressive 44 cm. You may remember we recently set an official record here at the Cape Eleuthera Institute with a 42 cm fish. So, when this new record breaker was laid before us on the dissection table, we decided to submit the numbers (and photo to prove it!) to the wider international community of fellow lionfish slayers. We can now proudly announce that our own 44 cm lionfish is the new official record for the whole Bahamas. Great work Dennis Johnson and Leonardo Butler for slaying this fish!
If you’re curious, the world record is currently held at 47.7 cm, so we’re not too far behind! Check out the Lionfish.co website for more details.
Matthew Smith is a Master’s student of the Ecology and Environment Lab from the University of Exeter in the UK. The main focus of his study is the effects of anthropogenic noise on reef fish populations, vocalisations and behaviour. There have been many studies on the effects of anthropogenic noise on marine mammals, but substantially fewer studies have be conducted concerning how noise pollution is affecting reef fish. Hearing and vocalisations are very important to many species found in the patch reefs such as those off of the coast of Cape Eleuthera. Boat traffic is an emerging threat that is often forgotten when assessing the threats to marine populations.
The primary study has involved selecting pairs of patch reefs with similar characteristics before splitting the pair into either treatment group, to receive increased or reduced boat traffic. By conducting fish surveys at regular intervals and recording using a hydrophone, Matthew is able to decipher if the changing levels of boat traffic is having an effect on the community living on each patch reef.
A secondary study is looking at the effect of boat traffic on damselfish (Stegastes spp.). Damselfish aggressively defend territories within which they preen a ‘garden’ of algae and have a heavy influence on algae populations on reefs as well as the behavior of fish in and around their territories. Using reefs that are less frequently exposed to boats, cameras are set up in front of damselfish territories to record how exposure to boat traffic affects their behavior. The end goal is to be contribute towards a better assessment of how anthropogenic noise pollution is affecting fish populations.