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Marine Life & Conservation Blogs

Reversing the decline of Bahamian reefs

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I recently got in touch with the Cape Eleuthera Institute in The Bahamas to ask about their work on coral reef conservation. I was delighted to “meet” Natalia Hurtado, MSc., Coral Reef Research Associate at PIMS/CEI & Casey Harris, MSc., Coral Reef Research Associate at PIMS/CEI. This is what they had to say about their important work.


Much like coral reefs worldwide, coral populations in The Bahamas are declining at alarming rates, making coral restoration more vital to preserve marine resources and local economies. The Bahamas Coral Innovation Hub located in Eleuthera, The Bahamas is a collaboration between the Cape Eleuthera Institute (CEI), Perry Institute for Marine Science (PIMS), and The Nature Conservancy (TNC). With our work, we hope to facilitate the recovery of degraded Bahamian reefs and enhance coral population resilience.

One major problem facing coral reefs worldwide is that coral abundance is decreasing due to both local and global threats, making it difficult for corals to maintain genetic diversity on the reef. At the same time, their ecosystem services are deteriorating, affecting human livelihoods and the diversity of marine species that rely on them. At the Coral Innovation Hub, we focus our restoration efforts on 3 main areas of research: nursery-reared coral fragments, larval propagation, and coral microfragmentation. We are also dedicated to student involvement in our research, with the goal of inspiring younger generations to pursue careers in marine conservation.  All projects at the Coral Innovation Hub are led by Natalia and Casey.

Nursery Establishment to Improve Genetic Diversity

Corals can reproduce asexually, in which they undergo a strategic life-history trait called “fragmentation”, where pieces of coral can break off from disturbance and then attach to the substrate to form a whole new colony. We can take advantage of this natural process to grow corals at a much faster rate and plant them back on degraded reefs. We do this by growing corals in a mid-water tree structure, which is made with PVC and tethered to the sea floor, where corals are suspended away from sediment and predators. Below is a picture of Researcher Casey Harris taking notes of coral sizes while an assistant is taking measurements.

The establishment of coral nurseries is an important step to keep coral fragments safe while they grow. Caribbean branching corals grow extremely fast and increase in size about 10-20 cm (4-9 in) per year compared to large boulder species, which only grow about 1-2 cm (<1 in) per year. This is great for restoration efforts because after one year of growing in the nursery, branching corals can be outplanted back on the reef.

We are currently running a project with Dr. Ross Cunning (pictured below) at Shedd aquarium and the Reef Rescue Network, where we are investigating the resilience of staghorn corals by spreading different genotypes across The Bahamas to increase genetic diversity within coral nurseries. We have 19 staghorn genotypes that were collected and moved between existing nurseries and wild populations throughout a few Bahamian Islands in October 2019. Increasing genetic diversity within coral nursery projects is important because some genetically distinct individuals may be better suited to withstand environmental stress than others. Having as many different genotypes as possible is essential to successful restoration outcomes.

During a 15-day expedition onboard the Shedd Aquarium research vessel R/V Coral Reef II, 570 staghorn corals were distributed between newly established nurseries located in Bimini, Nassau, Cat Island, and Eleuthera. In each location, coral growth has been monitored by our partners and they are thriving in their new locations.

Student Involvement as Reef Rescue Divers

The Coral Innovation Hub at CEI works closely with Island School students and visiting educational groups from different ages and backgrounds. These students have a unique opportunity to complete a PADI Reef Rescue Diver Specialty Course. This course was developed by Hayley-Jo Carr, Training Director & Coordinator of the Reef Rescue Network, and Dr. Craig Dahlgren, Executive Director of PIMS. The Reef Rescue Diver Specialty and Reef Rescue Network were both created by PIMS, with the goal of rehabilitating coral reefs by working with various partners to establish a network of coral nurseries around The Bahamas and other parts of the Caribbean.

During the course, students learn about the value of coral reefs and restoration, different types of nurseries, how to maintain nurseries, coral fragmentation, outplanting and monitoring. They work with Critically Endangered species, such as elkhorn and staghorn coral, that were once abundant on Caribbean reefs but have rapidly declined since the 1980s. We target these species for restoration because they play an important ecological role on the reef by providing high rugosity and three-dimensional functionality that protects our shorelines and provides shelter for marine life.

Implementing Larval Propagation as a Restoration Technique

Corals can also reproduce sexually. In sexual reproduction, corals release “spawn” (egg and sperm) and can synchronize their spawning events with colonies of the same species. Pictured below are the gamete bundles of a brain coral, in which the coral releases both egg and sperm (male and female gametes). We can take advantage of these spawning events to collect their spawn and cross fertilize them to increase genetic diversity, and study the vulnerable early life-history stages of corals.

During summer 2019, Coral Innovation Hub researchers collected coral gametes and saw high rates of fertilization and settlement success, with over 5,000 Orbicella faveolata (mountainous star coral) recruits (coral babies pictured below) settled on SECORE Seeding Units (concrete and ceramic substrates).

We are allowing juvenile corals to grow in an offshore nursery tree and outplanted more than 1,000 substrates with coral recruits onto the reef. The goal is to determine if initial and long-term coral survivorship is possible in an offshore nursery and/or on the reef. This research was conducted during SECORE’s International Coral Spawning and Propagation Workshop hosted at CEI with PIMS and TNC. Below is a picture of Researcher Natalia Hurtado carrying substrates to be outplanted on the reef.

A New Restoration Technique for Boulder Corals

Another way to grow corals through asexual reproduction is by using a new restoration technique for slow-growing boulder species called “microfragmentation,” founded by Dr. David Vaughan, Plant a Million Corals. This process consists of cutting fragments of the same colony into small pieces (1-3 cm, pictured below), using a specialized saw. The clone fragments will recognize each other and fuse together, growing 25-50 times faster than normal.

At the Coral Innovation Hub, we plan to run pilot experiments on different coral species to document the most successful microfragmentation methods needed to upscale our efforts. As part of our study, we will examine the survivorship and growth of microfragmented boulder corals (brain corals, star corals, etc.) in our land-based wetlab facility (pictured below). If proven successful, we will grow boulder corals in an offshore table nursery or directly outplant microfragments to the reef.

Want to know more about Reef Rescue Network? Please contact Hayley-Jo Carr. If you have any questions or want to get involved with The Bahamas Coral Innovation Hub project, please contact Natalia Hurtado or Casey Harris.

Nick and Caroline (Frogfish Photography) are a married couple of conservation driven underwater photo-journalists and authors. Both have honours degrees from Manchester University, in Environmental Biology and Biology respectively, with Nick being a Fellow of the Royal Photographic Society, a former high school science teacher with a DipEd in Teaching Studies. Caroline has an MSc in Animal Behaviour specializing in Caribbean Ecology. They are multiple award-winning photographers and along with 4 published books, feature regularly in the diving, wildlife and international press They are the Underwater Photography and Deputy Editors at Scubaverse and Dive Travel Adventures. Winners of the Caribbean Tourism Organization Photo-journalist of the Year for a feature on Shark Diving in The Bahamas, and they have been placed in every year they have entered. Nick and Caroline regularly use their free time to visit schools, both in the UK and on their travels, to discuss the important issues of marine conservation, sharks and plastic pollution. They are ambassadors for Sharks4Kids and founders of SeaStraw. They are Dive Ambassadors for The Islands of The Bahamas and are supported by Mares, Paralenz, Nauticam and Olympus. To find out more visit www.frogfishphotography.com

Marine Life & Conservation Blogs

Creature Feature: Undulate Ray

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In this series, the Shark Trust will be sharing amazing facts about different species of sharks and what you can do to help protect them.

This month we’re looking at the Undulate Ray. Easily identified by its beautiful, ornate pattern, the Undulate Ray gets its name from the undulating patterns of lines and spots on its dorsal side.

This skate is usually found on sandy or muddy sea floors, down to about 200 m deep, although it is more commonly found shallower. They can grow up to 90 cm total length. Depending on the size of the individual, their diet can range from shrimps to crabs.

Although sometimes called the Undulate Ray, this is actually a species of skate, meaning that, as all true skates do, they lay eggs. The eggs are contained in keratin eggcases – the same material that our hair and nails are made up of! These eggcases are also commonly called mermaid’s purses and can be found washed up on beaches all around the UK. If you find one, be sure to take a picture and upload your find to the Great Eggcase Hunt – the Shark Trust’s flagship citizen science project.

It is worth noting that on the south coasts, these eggcases can be confused with those of the Spotted Ray, especially as they look very similar and the ranges overlap, so we sometimes informally refer to them as ‘Spundulates’.

Scientific Name: Raja undulata

Family: Rajidae

Maximum Size: 90cm (total length)

Diet: shrimps and crabs

Distribution: found around the eastern Atlantic and in the Mediterranean Sea.

Habitat: shelf waters down to 200m deep.

Conservation Status : As a commercially exploited species, the Undulate Ray is a recovering species in some areas. The good thing is that they have some of the most comprehensive management measures of almost any elasmobranch species, with both minimum and maximum landing sizes as well as a closed season. Additionally, targeting is entirely prohibited in some areas. They are also often caught as bycatch in various fisheries – in some areas they can be landed whilst in others they must be discarded.

IUCN Red List Status: Endangered

For more great shark information and conservation visit the Shark Trust Website


Image Credits: Banner – Sheila Openshaw; Illustration – Marc Dando

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Guarding Against Coral Invaders

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Protecting (Dutch) Caribbean Reefs from Unomia stolonifera

Recent reports highlight the concerning spread of the invasive soft coral, Unomia stolonifera, currently devastating Venezuela’s marine ecosystems and detected in Cuba. With the potential threat of its expansion to the (Dutch) Caribbean islands, urgent action and awareness are essential to safeguard marine biodiversity and local economies from possible catastrophic consequences.

Invasive species are animals or plants from another region of the world that don’t belong in their new environment. These species can have major ecological effects by decimating native flora or fauna. They can also cause large economic losses and impact human health. Invasive species also pose a significant threat to marine ecosystems worldwide, including the Dutch Caribbean. Among these invaders is the octocoral species Unomia stolonifera or “Pulsing Xenia”, originally from the Indo-Pacific. With its rapid growth and lack of natural predators, this species can outcompete native species and disrupt fragile marine habitats such as seagrass beds and coral reefs.

Background

The invasive soft coral U. stolonifera was first identified in 2014, off the coast of Venezuela. It is believed to have been introduced via the illegal aquarium trade.  Since this species can reproduce sexually and asexually (or fragment), even small pieces can regenerate to spread.  Once introduced it quickly took over shallow reefs and hard substrate at depths of 0-50 meters, outcompeting local corals and seagrass for space.  Follow on surveys found that this coral species exhibited average percentage cover as high as 80%, vastly outcompeting native corals. In highly colonized areas, fish are disappearing due to loss of habitats.

In 2022, during a survey conducted in Cuba by the University of Havana, an unknown octocoral was discovered which was later identified as the invasive Unomia stolonifera. It is suspected that the coral larvae arrived in ballast water from fossil fuel ships originating from Venezuela, as nearby sites adjacent to Venezuelan ports have been heavily affected by the invasion.

How to help

Prevention through continuous monitoring, particularly in high-risk areas such as marine harbors and oil facilities, is paramount. Early detection plays a pivotal role in mitigating the threat posed by Unomia stolonifera.

The public’s involvement and awareness are also vital. Local communities, recreational divers, tourists, and all stakeholders are urged to participate in early detection efforts by reporting sightings (photo, location and date) of this invasive coral to their respective Protected Area Management Organization (PMO’s)- the Fundacion Parke Nacional Aruba (FPNA)STINAPA BonaireCARMABI Curaçao Saba Conservation Foundation (SCF)Nature Foundation St. Maarten (NFSXM) and St. Eustatius National Parks (STENAPA). If an invaded area is confirmed, follow the recommendations by the local PMO’s.

Keys to Success

Despite the challenges, early detection is key to mitigating the threat posed by Unomia stolonifera. With continued vigilance, research, and community engagement, there is hope for containing this potential issue before it becomes a major threat.

About the DCNA

The Dutch Caribbean Nature Alliance (DCNA) supports (science) communication and outreach in the Dutch Caribbean region by making nature related (scientific) information more widely available through amongst others the Dutch Caribbean Biodiversity Database, DCNA’s news platform BioNews and through the press. This article contains the results from several scientific studies but the studies themselves are not DCNA studies. No rights can be derived from the content. DCNA is not liable for the content and the in(direct) impacts resulting from publishing this article.

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