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Reef ecology

Patch reef survey time!

Last week the Reef Ecology and Restoration team completed the March monitoring surveys of the 5 year reef study around the patches of Eleuthera. The March surveys usually call for thick wetsuit, hoods and hot chocolate. However, the water was particularly warm at 27oC, resulting in the surveys being completed in record time. Dr Jocelyn Curtis-Quick has been leading this study since 2012; she now plans to use this incredibly unique and invaluable dataset to thoroughly examine the influences and impacts that the invasive lionfish have on the patch reef ecosystem. Every part of the reef is searched for lionfish

The Reef Ecology team has already begun the process of analysis, and Jocelyn was able to present some of these preliminary findings at the Bahamas Natural History Conference in Nassau earlier in the month. By continuing to spread and enhance the local knowledge within Eleuthera and beyond, the management of the lionfish will hopefully continue to grow.

Removing lionfish from the reef

Of the 16 patches that have been surveyed throughout the study, 8 have been designated as removal sites, and with a highly experienced team we were able to continue our contribution to the culling effort around The Bahamas and wider Caribbean. Stay tuned to hear the full results of our study and a more detailed picture of how the lionfish is making its presence felt around Southern Eleuthera. In the mean time don’t forget, You Slay, We Pay!

Research to protect Eleuthera seahorses

Dr. Jocelyn Curtis-Quick and her team have been assisting Dr. Heather Masonjones with her ongoing seahorse research in Sweetings Pond. Sweetings Pond on the island of Eleuthera contains a diverse array of species, including both seahorses and octopuses. Originally described in the early 1980’s, this pond has remained unstudied over the past 30 years. The amazing seahorses of the pond (photo credit Shane Gross)

This type of tidal saltwater pond forms in regions with limestone geologic histories, fed from the ocean through cracks and underground caverns. Depending on the size of these connections and how long they have been isolated from gene-flow, these ponds are well known sites of speciation, with an array of endemic or limited-range organisms, and unfortunately, a long list of species declines. The Sweetings Pond site is part of wider assessment of the inland ponds found all over Eleuthera, led by Dr. Jocelyn Curtis-Quick.

All seahorses found are photographes as their marking can be used to identify individuals

Seahorses are marine fish that have captivated humans for generations. Worldwide, their populations are under threat from over-harvesting for curios, traditional medicines and as bycatch from fisheries. They are also declining because of decreasing water quality of their shallow coastal habitats, and increased use of these habitats through poorly-managed tourism. The impacts of these threats are difficult to measure in seahorses, because they are difficult to study in the wild.  The pond species of seahorses, Hippocampus erectus, is also listed as Vulnerable on the IUCN Red List, an international organization dedicated to conservation.

At night a black light shows the tagged fish (photo credit Shane Gross)

Lili Wagner finds a baby octopus on the light trap

The team spent two days assessing the seahorse's use of different habitats and successfully tagged more than 30 seahorses, enabling the mark and recapture technique to be used to assess population density. In order to assess what the seahorses are eating, as there is little to no research on their prey selection at night, the team set out plankton tows and executed gastric lavage procedures on the seahorses. The stomach contents were preserved and will be sent to a lab at the University of Tampa to be analyzed, and the animals were released unharmed back to the exact location where they were originally found. Because of their monogamous mating system, moving animals from their home location can interrupt mating pairs, and make it difficult for animals to reproduce.

Populations of seahorses are rarely as dense as we have measured in the pond, so from a conservation perspective, this would be an excellent choice of location to protect and conserve for future generations.  Dr. Masonjones presented the preliminary findings at the Bahamas Natural History Conference last week.

If you see seashores in the water around Eleuthera please report your sightings on iSeahorse.

Professor Wicksten visits CEI

Prof. Wicksten exploring the inland ponds The Reef Ecology and Restoration team welcomed Prof. Mary Wicksten to CEI last week. Prof. Wicksten is a professor at Texas A&M University, College Station, where she works on the biogeography, systematics and behavior of decapod crustaceans. Prof. Wicksten is collaborating with CEI’s Dr Jocelyn Curtis-Quick on the anchialine pond research.

Rare shrim found in the ponds of Eleuthera. Photo credit: Drew Hitchner

During Prof. Wicksten’s visit, she got to explore some of the inland ponds and helped to identify deep sea crab species for other researchers at the institute. Prof. Wicksten used her expert ID skills to also identify crabs and shrimp present in the stomach contents of some lionfish. Prof. Wicksten had the opportunity to talk with the young ones from the ELC about crustaceans – inspiring future scientists!

Although a short visit to the CEI, Prof. Wicksten made the most of her time, and even helped to support the ongoing lionfish outreach.  She attended the Blue Seahorse art show, where the Reef Ecology team was increasing lionfish awareness, particularly the importance of removing the lionfish from the reefs and spreading the word that it is a really good fish to eat!

It was a pleasure to have Prof. Wicksten with us for four amazing days!

Nassau grouper spawning aggregation expedition

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. The researchers that took part in the Nassau grouper work in front of the Shedd Aquarium vessel

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. 

Throughout the trip, amidst the dive surveys, Nassau grouper were  implanted with transmitters. These transmitters track the movements of the Nassau grouper from the spawning sites back to their original habitat with strategically placed receivers, in efforts to understand where they come from and how far these fish travel to these spawning sites. At the spawning site, the five receivers were extracted and replaced with new receivers. The data from the receivers showed the movements of the Nassau grouper which will add to Dr. Stump's dataset. Blood samples were also collected from these fish for Krista Sherman from Exeter University, who is using this blood to look at hormone levels and ways of determining sex of grouper non-invasively.

Although the weather failed to cooperate, four fish were implanted with transmitters which will help provide data for the upcoming spawning period, and the receivers have provided Shedd Aquarium with useful data.

 

Lionfish, and conch, and sea turtles, and aquaponics, oh my!

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. The CEI team in front of their booth at Governors Harbour Homecoming

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 CEI booth with information on lionfish, queen conch, sea turtles, and aquaponics

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.