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Marine Life & Conservation

Komodo National Park found to be Manta Hotspot

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Through a collaborative effort between citizen divers, scientists from the Marine Megafauna Foundation (MMF), and Murdoch University, a new study reports a large number of manta rays in the waters of Komodo National Park, Indonesian, a UNESCO World Heritage Site, suggesting the area may hold the key to regional recovery of the threatened species.

Reef mantas (Mobula alfredi), which grow up to 5m, tend to reside and feed in shallow, coastal habitats. They also visit ‘cleaning stations’ on coral reefs to have parasites, or dead skin picked off by small fish. Courtship ‘trains’ are also observed adjacent to cleaning stations. In Komodo National Park, manta rays are present year-round, challenging the famous Komodo dragon as the most sought-after megafauna for visitors.

Scientists teamed up with the dive operator community to source identification photographs of manta rays visiting the parks’ waters and submit them to MantaMatcher.org – a crowdsourced online database for mantas and other rays. Most of the photographs came from just four locations from over 20 commonly visited by tourism boats.

I was amazed by how receptive the local dive community was in helping collect much-needed data on these threatened animals,” said lead author Dr. Elitza Germanov. “With their support, we were able to identify over 1,000 individual manta rays from over 4,000 photographs.

People love manta rays—they are one of the most iconic animals in our oceans. The rise of the number of people engaging in SCUBA diving, snorkeling, and the advent of affordable underwater cameras meant that photos and videos taken by the public during their holidays could be used to quickly and affordably scale data collection,” said MMF co-founder and study co-author Dr. Andrea Marshall.

The photographs’ accompanying time and location data is used to construct sighting histories of individual manta rays, which can then be analyzed with statistical movement models. These models predict the likelihood that manta rays are inhabiting or traveling in between specific sites. The study’s results showed that some manta rays moved around the park and others as far as the Nusa Penida MPA (>450 km to the west), but overall, manta rays showed individual preferences for specific sites within the Park.

I found it very interesting how some manta rays appear to prefer spending their time in some sites more than others, even when sites are 5 km apart, which are short distances for manta rays,” said Dr. Elitza Germanov. “This means that manta rays which prefer sites where fishing activities continue to occur or that are more popular with tourism will endure greater impacts.”

Fishing activities have been prohibited in many coastal areas within Komodo NP since 1984, offering some protection to manta rays prior to the 2014 nationwide protection. However, due to illegal fishing activity and manta ray movements into heavily fished waters, manta rays continue to face a number of threats from fisheries. About 5% of Komodo’s manta rays have permanent injuries that are likely the result of encounters with fishing gear.

The popularity of tourism to these sites grew by 34% during the course of the study. An increase in human activity can negatively impact manta rays and their habitats. In 2019, the Komodo National Park Authority introduced limits on the number of boats and people that visit one of the most famous manta sites.

This study shows that the places where tourists commonly observe manta rays are important for the animals to feed, clean, and mate. This means that the Komodo National Park should create measures to limit the disturbance at these sites,” said Mr. Ande Kefi, an employee of the Komodo National Park involved with this study. “I hope that this study will encourage tourism operators to understand the need for the regulations already imposed and increase compliance.”

Despite Indonesia’s history with intensive manta ray fisheries, Komodo National Park still retains large manta ray aggregations that with careful ongoing management and threat reduction will benefit regional manta ray populations. The study highlights that marine protected areas that are large enough to host important manta ray habitats are a beneficial tool for manta ray conservation.

For more information about MMF visit their website here.

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Can reef conservation be both enjoyable and profitable?

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wakatobi

At Wakatobi Dive Resort, guests are always thanked for coming to enjoy this special place, as it is their presence that creates the magic making ongoing reef conservation efforts a reality. “The more you know, the more you notice,” says in-house marine biologist Julia Mellers. “And what better place to learn about reef biodiversity and custodianship than in Wakatobi.”

“My main project for the first year is to establish a way of monitoring the health of Wakatobi’s reef ecosystem,” Julia says. “This will allow us to provide hard scientific proof that Wakatobi’s conservation model measurably benefits reef health. Holding a finger to the pulse of the reef will also assist management decisions, such as identifying priority areas for increased protection.”

Modern methods for reef management

The Wakatobi Reef Health Assessment program utilizes a customized set of modern imaging and data analysis techniques that provide a comprehensive indication of the state of a reef ecosystem. “We use the latest ecological theory, technology, and artificial intelligence to develop a novel package to efficiently and robustly measure reef health,” Julia says. “This will enable us to monitor how Wakatobi’s reefs are faring throughout the protected area without significantly diverting resources from protecting the reefs.”

The process begins in the water, capturing the reef’s sights, sounds, and landscape. Above water, Julia is developing and implementing analysis methods and training machine learning models to extract measures of reef health from captured data. When not on the island, she will research new approaches and ideas for coral reef assessment and help spread the word about Wakatobi’s scientific initiative.

“It’s an absolute privilege to work within a system that benefits both the reefs and the local people,” says Julia. “It also gives us a unique opportunity to assess and document reef health and dynamics within an ecosystem that is actually getting healthier. In stark contrast to declines in coral health recorded elsewhere, our scientific data is already beginning to demonstrate Wakatobi’s astonishing biodiversity – which is evident to anyone who ventures underwater at the resort.”

The program focuses on three indicators of reef health: the diversity of the reef community, which measures the variety and abundance of living organisms colonizing the reef surface; structural complexity, describing the degree to which the reefs incorporate elaborate details; and reef soundscapes, recording the noise a reef’s inhabitants make, including the snapping of shrimp and the feeding sounds of fish. By measuring these elements, it is possible to estimate how much life the habitat supports.

“Luckily, we don’t have to work all that out manually,” Julia says. Artificial intelligence plays a vital role. “I train machine learning models to identify signals of reef functioning that would otherwise be undetectable. For example, a model can be trained to recognize the sounds that characterize a healthy reef. This allows us to monitor the reefs at a scale, and with a thoroughness that would otherwise be inconceivable.”

Julia and the dive team have also started an eDNA survey of the reefs. ”This involves taking seawater samples near the reef at different depths and filtering them to trap environmental DNA (eDNA) that organisms shed into the water,” Julia explains. “The samples are now in a lab, where the DNA is labeled using probes and sequenced to identify which species are around. Using this technique, we should be able to detect hundreds of species from just a single litre of seawater. It’s a very cool process!”

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A Wakatobi welcome

Julia says the Wakatobi team has been exceptionally supportive and welcoming. “They are able to maintain a totally laid-back atmosphere while coordinating an exceptionally professional operation.” She adds that Wakatobi feels remote in the best ways, with pristine reefs, peace, and quiet, while also being an extremely comfortable and well-connected place to work.

“Working within a system that works for the reefs because it works for the people is an absolute privilege,” she says. “It also gives us a unique opportunity to unpick reef health and dynamics within an ecosystem that is actually getting healthier. In stark contrast to declines recorded elsewhere, our scientific data is already beginning to demonstrate the astonishing biodiversity evident to anyone who ventures underwater at Wakatobi.”

The Wakatobi team has also proven to be an invaluable source of knowledge about the local ecosystem,” Julia says. “Wakatobi makes the perfect scientific laboratory. Being able to go from library to laptop to reef, all in the space of a hundred meters, is the perfect recipe for generating new ideas and trying them out. It is so exciting to work with open-minded innovators keen to try novel approaches and look at things from different angles.”

“Having such a dynamic team has meant that we’ve made progress quickly,” Julia says. “So far, we have a highly accurate machine learning model that classifies the reef community, a method to analyze the sounds that reef critters make, and a fully automatic way of measuring fish abundance. We are also in a position to add to this repertoire, trialing different techniques to quantify the complex 3D structure that corals make. We have added DNA analysis to the arsenal, which enables us to detect biodiversity invisible to the naked eye.”

From frogs to frogfish

Julia acquired her love of nature and biology from her parents, whom she describes as eco-friendly before the concept became trendy. “Camping, compost heaps, and Attenborough documentaries were features of a nature-centric English childhood. I raised pond-dwelling critters, peered down microscopes, and became transfixed by cephalopods.” Biology was an inevitable choice, she says, and the sea came into her life at a young age. “Having long been a sailor, with a family of sailors, I am at home at sea,” she says. “I took my first sip of compressed air at the bottom of a swimming pool in London and have spent as much time as possible eye-to-eye with octopuses since.”

After completing an undergraduate degree in biology at Oxford University, Julia shifted her Master’s focus to marine biology. It was a move she describes as swapping frogs for frogfish. “I went into marine biology because I see marine biological research as a powerful tool to connect people with the planet,” she says. “Of course, nature should be worth more to us preserved than destroyed – but if you can’t put a price on it, no one pays. Wakatobi has created an economic engine that financially incentivizes reef custodianship. This leads to an ideal scientific setting – demonstrably vibrant reefs linked to genuine socio-economic fairness.“

Julia’s Master’s project was done in collaboration with the Australian Institute of Marine Science and investigated mysterious bare rings of sand that surround reef patches within algal meadows. “We think these ‘reef halos’ form because foraging fish will only venture a short way from the shelter of a coral patch if they are under threat from patrolling sharks,” she says. “Since you can spot these halos from satellite images, they could be a neat way of keeping an eye on shark populations from space… and a possible addition to Wakatobi’s monitoring program”!

As the Reef Health Assessment program progresses, Julia will create new learning and participation opportunities for guests to enhance the depth and enjoyment of their Wakatobi experience. Wakatobi Dive Resort will also continue to provide updates and insights on the important work Julia and the rest of the Wakatobi team are doing to understand and protect some of the world’s most pristine and spectacular coral reefs.

Many thanks go to Wakatobi’s guests, whose continued enjoyment of the marine preserve helps keep ongoing reef protection efforts a reality!

Contact the team at office@wakatobi.com or enquire >here.
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View Wakatobi videos on the YouTube Channel.

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Marine Life & Conservation

Book Review: Coral Triangle Cameos

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Coral Triangle Cameos. Biodiversity and the small majority by Alan J Powderham

This colourful coffee table style book wonderfully shows off the incredible and vibrant marine life of an area, roughly triangular, that spans the waters of Indonesia, Malaysia, the Philippines, Papua New Guinea, the Solomon Islands, and Timor-Leste. The biodiversity here is incredibly rich. And this book covers the wonders that those lucky enough to dive here can experience.

It is worked into chapters that cover the types of marine life found here from coral to worms and everything in-between. The chapter on corals features lovely wide angle scenes, as well as close up details. And all the following chapters contain stunning images and interesting descriptions of both common and rare animals that have divers flocking to this region to discover. I think the cephalopods are my favourite. But this book certainly offers plenty of other options to marvel at.

This is a book to dip in and out of. Enjoy the beautiful images within (of which there are many). Peruse the descriptions of your personal favourite species and learn about new behaviours and interactions that are part of every day life on these abundant reefs. It is the type of book that will keep you coming back over and over again. And will always bring a smile to your face as you explore this incredible underwater world and the marine life that calls it home.

What the Publisher Says:

Dive into the Hidden Wonders of the Coral Triangle, a kaleidoscope of marine life which boasts the greatest biodiversity in the oceans. While most focus on the giants of the deep, Coral Triangle Cameos celebrates the “small majority” — the tiny but vital creatures that power this underwater paradise.

Renowned underwater photographer Alan Powderham brings the unseen to life with stunning visuals and he divulges the fascinating science behind these diminutive wonders in an accessible, relatable way.

About the Author:

Alan J Powderham is a seasoned underwater photographer with over 40 years of experience capturing the magic of the ocean depths. His previous books include At the Heart of the Coral Triangle (2021).

Book Details

Publisher: Dived Up Publications

Hardcover

Price: £45

ISBN: 978-1-909455-57-3

Published: 17th September, 2024

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