Will climate change have an effect on the lionfish invasion?

With rising atmospheric carbon dioxide (CO₂), primarily from anthropogenic impacts, oceans are absorbing CO₂ at an alarming rate. This additional CO₂ changes seawater pH and chemical composition, profoundly affecting marine ecosystems. Future predictions highlight a continual increase in CO₂, which several studies have shown to affect a broad range of marine organisms, including ecologically important plankton, coral and fish species.  A species which lacks any CO₂ related research however, is the invasive lionfish. Lionfish have a resilient nature, with a temperature tolerance range of 10˚C – 35˚C and a salinity tolerance range of 7ppt – 35ppt. Coupled with the ability to produce 30,000 eggs every two to three days, a lack of predators and a broad habitat type, there seems to be no barrier to this well adapted invader. Now prevalent in their invaded range in the Western Atlantic in an area of over 7 million km² in just 25 years, and with the ability to decrease native fish populations by 65%, studies into resilience to other environmental factors is fundamental in predicting future impacts.

 

Lionfish acclimating in our wetlab here at CEI.
Lionfish acclimating in our wetlab here at CEI.

Research Technicians Helen Conlon and Rob Drummond, supervised by Dr. Shultz and Dr. Curtis-Quick, started their collaborative independent research project investigating whether future worst case scenario CO₂ levels has the potential to affect invasive lionfish hunting behaviour and physiology. Results will aid the mitigation management of the invasion, either by additional emphasis for the need for immediate control methods, or concluding that hunting will be altered in the presence of increased CO₂. Stay tuned for more updates!

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New study assessing seagrass productivity across South Eleuthera

This semester, the Sea Turtle Research and Conservation team has been collecting seagrass samples from various study sites around South Eleuthera where green sea turtles have been sighted since the start of the program in 2012. The new study will assess the productivity, composition and distribution of seagrass and compare this to the relative abundance of the local green turtle (Chelonia mydas) population on each site.

Quadrat use to estimate seagrass and algae cover
Quadrat use to estimate seagrass and algae cover

Seagrass communities are one of the most productive and dynamic ecosystems globally. They provide habitats and nursery grounds, and act as substrate stabilizers. Also, seagrass meadows are a major food source for a number of grazing animals and are considered very productive pastures of the sea. For example, an adult green turtle can eat about two kilograms of seagrass a day, which helps to maintain a healthy environment, increasing the productivity and nutrient content of seagrass.

Monitoring seagrass resources is important for two reasons: it provides a valuable tool for improving management practices and it allows us to know the status and condition of these ecosystems.

Seagrass sample from Broad Creek
Seagrass sample from Broad Creek

It is known that the die-off or decline of seagrass has a direct effect on green turtle populations.  We know that seagrass meadows are exploited year-round mainly by juvenile and sub-adult green turtles and their distribution may be related to the dynamics of the seagrass beds. For example, in Florida Bay and the Gulf of Mexico the loss of seagrass cover during the 1980’s was linked to the ecological extinction of green turtles. The decrease on the cover and density of seagrass and green turtle population worldwide might be in some level due to natural causes (diseases, storms, etc), but the major threat facing both seagrass and sea turtles are human interactions (pollution, habitat degradation, direct or indirect take, among others).

The team and the Island School research class have been collecting seagrass samples, then counting and weighing seagrass shoots and leaves to assess the biomass (above and below ground) and density of the different species of seagrass found in those study sites. The results of this research will be presented by students of The Island School at the end of May Island School Research Symposium.

Spring Island School class 2016 after a day of sampling seagrass
Spring Island School class 2016 after a day of sampling seagrass

This event is an opportunity to learn more about the ongoing research carried out at the Cape Eleuthera Institute so please contact Candice Brittain if you are interested in attending (candicebrittain@islandschool.org).

Follow our sea turtle research here.

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Check out this bonefish research happening at night!

The research team led by Dr. Aaron Shultz and Georgiana Burruss (CEI) spent four nights out manually tracking bonefish spawning aggregations near Cape Eleuthera. Bonefish school at a nearby location and move along the coast at night to spawn in deep water. By tracking the fish offshore at night, the team will gain an understanding of where and when the aggregation is spawning as well as how weather, lunar phase, and tidal cycle might impact spawning patterns.

Directional and omnidirectional hydrophone are used with the VR100 receiver to track bonefish
Directional and omnidirectional hydrophone are used with the VR100 receiver to track bonefish

The team deployed two gastric transmitters that signal the receiver every second, allowing the bonefish to be tracked manually using a VEMCO VR100 receiver. To deploy the gastric transmitters, bonefish are captured from the aggregation using a handline. The transmitter is then pushed down the esophagus of the fish using a small tube. Each fish is given an hour to recover and then returned to the aggregation. At sunset, the fish in the aggregation move to the surface of the water, exhibiting a behavior called porpoising, in which the bonefish rush to the surface and gulp air. This behavior typically occurs several hours before bonefish move down to depths of over 150ft. After sunset, the team follows the aggregation overnight, taking GPS waypoints every 15 minutes. This data is used to generate a path that the aggregation takes from sunset to sunrise. Over 4 nights, the aggregation moved from shallow coral reef areas(<2m) to deep open ocean environments (>30m) and then returned to their prespawning site by sunrise. Several studies have suggested that bonefish aggregations move to deep water to spawn; we have tracked two trips to the Exuma Sound so far. Interestingly, one of the tagged barracuda closely followed the bonefish aggregation for over 6 hours!

Gastric transmitter inserted into the bonefish
Gastric transmitter inserted into the bonefish
Mature male bonefish captured by a handline from a bonefish prespawning aggregation
Mature male bonefish captured by a handline from a bonefish prespawning aggregation

The team hopes to track bonefish aggregations to their spawning sites over the coming months. For more information about our research and how to support, please contact georgianaburruss@islandschool.org and aaron.dean.shultz@gmail.com. Stayed tuned for more updates!

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New study addressing predator interactions with bonefish spawning aggregations

In February, the research team led by Dr. Aaron Shultz and Georgiana Burruss (CEI) successfully implanted the last bonefish with an acoustic transmitter, bringing the sample size to 39 bonefish that they will track over the next three years! The data collected from these fish will provide insight into the locations of movement corridors and prespawning aggregations, as well as potential cues for bonefish spawning (e.g., moon cycle, tidal cycle, weather patterns, etc.). These locations can then be used to designate marine protected area that will aid in the conservation of this ecologically and economically important species.

Team preps for surgery
Team preps for surgery

 

 

 

 

 

 

 

A second study was recently launched to evaluate if bonefish prespawning aggregations  attract predators. Anecdotally, coastal predators such as sharks and Great Barracuda have been observed preying on spawning aggregations of bonefish. Unfortunately, these associations between predators and spawning aggregations are not well-studied, resulting in a knowledge gap regarding how bonefish aggregations could dictate the abundance of apex predators in localized areas. Using a known bonefish prespawning aggregation as a model, this study aims to determine if bonefish aggregations attract predators and if these predators are returning to the aggregation site repeatedly. Barracuda are a known predator of bonefish in shallow flats and they are common near the location of the bonefish prespawning aggregation, making them an ideal species to study predator movement patterns in relation to bonefish aggregation.

With the assistance of Zach Zuckerman, barracuda were captured using SpiderWire and Dyneema fishing line at locations near and far-away from the bonefish prespawning aggregation. VEMCO acoustic transmitters were surgically implanted into 14 barracuda. These fish will be tracked passively, utilizing the receiver array placed around the island, as well as actively, when researchers are tracking bonefish aggregations overnight. Surprisingly, one barracuda closely followed a bonefish spawning aggregation for over 6 hours!

Georgie Burruss closes the incision on a Great Barracuda
Georgie Burruss closes the incision on a Great Barracuda

 

 

 

 

 

 

 

This study will continue to track bonefish and predator movements around Eleuthera over the next three years. For more information about our research and how to support, please contact georgianaburruss@islandschool.org and aaron.dean.shultz@gmail.com. Keep an eye out for more updates!

 

 

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First Island School Student to Presents Research Poster at BNHC

Andrieka presenting the ponds research
Andrieka presenting the ponds research

CEI was well represented at the regional 2016 Bahamas Natural History Conference, with representatives giving talks on plastics, climate change, rare shrimp, turtles, conch, sharks and lionfish. More excitingly, the first Island School alumni joined with the research team! Andrieka Burrows, BESS scholar of Fall 2015, attended the conference to present the anchialine ponds poster. Anchialine ponds are landlocked bodies of water with marine characteristics that are connected to the sea through underground conduits. There are over 200 of these ponds on the island of Eleuthera, however, there is very little known about these ecosystems. Dr. Jocelyn Curtis-Quick and Alexio Brown, with a team of Island School students, including Andrieka, gathered baseline data on the ponds in order to determine their status and need for protection.

There was much interest in the inland ponds work
There was much interest in the inland ponds work
Research advisor Alexio Brown and Dr Curtis-Quick were very proud of Andrieka
Research advisor Alexio Brown and Dr Curtis-Quick were very proud of Andrieka

The students found an alarming number of the ponds were impacted by humans.  To conserve these ecosystems, there is a need to raise awareness. Andrieka did this by presenting the work of her research class at the Bahamas Natural History Conference (BNHC). The conference was hosted by the Bahamas National Trust (BNT), who manage the protected areas in The Bahamas. Andrieka spoke about why these ponds are so understudied, and her hopes for more research to be carried out in the future.

“The Bahamas Natural History Conference turned out to be all that I expected,” said Andrieka. “Not only did I get the opportunity to interact with world renowned scientists, who presented their captivating work, but I also got to present my anchialine pond research to these very same scientists.”

Andrieka created much interest in ponds, and did an exceptional job presenting the poster, making her research very advisors proud.

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Flats team picks up acoustic receivers and finds elkhorn coral

Georgie Burruss secures a receiver to a cinderblock after downloading the data from the device.
Georgie Burruss secures a receiver to a cinderblock after downloading the data from the device.

Last week, the Flats Ecology and Conservation team downloaded data from a large-scale passive acoustic telemetry array designed to track bonefish to their pre-spawning aggregations. A total of 61 receivers were placed around Eleuthera to track the movements of 39 bonefish and 14 barracuda that were implanted with acoustic transmitters. The research team downloaded key receivers and found schools of bonefish moving over coral reef habitats at night near tidal creeks on the East coast of Eleuthera, indicating that these fish may move offshore to spawn on the windward side of the island. Stay tuned for more updates in June.

A healthy stand of Elkhorn coral
A healthy stand of Elkhorn coral
Helen Conlon signals okay after redeploying a receiver.
Helen Conlon signals okay after redeploying a receiver.

As a bonus, while collecting receivers the team got to swim by several Elkhorn coral (Acropora palmata) colonies, an IUCN-listed critically endangered species. Elkhorn coral grows rapidly, providing significant structure and habitat for reefs throughout the Caribbean, though it is in severe decline as a result of coral bleaching, predation, storm damage, disease, and human activity. Though it was heartening to see so many healthy colonies of this critically endangered species, they are small compared to the large stands of dead elkhorn that used to thrive in the area. Our reef restoration project has begun mapping these areas and will be monitoring its growth.

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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
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
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!

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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)
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
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)
At night a black light shows the tagged fish (photo credit Shane Gross)
Lili Wagner finds a baby octopus on the light trap
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.

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Professor Wicksten visits CEI

Prof. Wicksten exploring the inland ponds
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
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!

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Queen conch “graveyard” study taking place at CEI

An adult conch in the shallow water
An adult conch in the shallow water

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.

Selecting conch at random to  be used in a trial
Selecting conch at random to be used in a trial

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?

Sustainable Fisheries intern Cara measures the distance moved by a conch in a behavioral trial
Sustainable Fisheries intern Cara measures the distance moved by a conch in a behavioral trial

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!

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