Coral Reefs

The Heat is on for the Survival of Chagos Archipelago’s Coral Reefs

Original post:

Back-to-back heatwaves kill more than two-thirds of coral.

The heat is on for the survival of the Chagos Archipelago's coral reefs.

ZSL scientists have shown the devastating effects of back-to-back heatwaves in the region surrounding the Chagos Archipelago. Coral cover was reduced by 60% in 2016 and by a further 30% in 2017. Nonetheless, this also indicates that some coral species have a higher resilience to rising temperatures thus offering some hope for the future.

Although representing les than 1% of our marine habitats coral reefs harbour a quarter of marine life. There are strong economic, conservation and scientific reasons for us to safeguard these reefs in a changing world.

In 2015 an eight weeklong heatwave struck the Chagos Archipelago, causing the seawater of the area to be unusually hot for a prolonged period. Researchers compared surveys of the reef before and after the heatwave in order to map the changes and harm it caused to the reefs. Evidence from 2015’s observations shows a 60% reduction in coral cover in the MPA. This included a dramatic 86% decline in the branching Acropora species that was previously a dominant reef building coral.

A year later, and before any recovery was possible, this region was subject to another bleaching event caused by a four-month long heatwave. Using data from Peros Banhos atoll an estimated 68% of the remaining corals had bleached. This suggest that around 70% of the reef area covered by corals was lost between 2015/2017.

Although more severe than the first heatwave, the second did less damage than the previous one. The first one killed corals most vulnerable to heat stress, leaving the more resilient colonies to try and survive the second. The fact that a few species have a higher heat tolerance is a glimmer of hope. According to Dr. Catherine Head the increasing severity and occurrence of heatwaves will inhibit shallow reefs ability to regenerate from bleaching events. It previously took 10 years for coral reefs to regenerate in BIOT, there is a high probability that the more vulnerable coral species will completely die off in the near future if these bleaching events become more frequent.

Preliminary reports from 2019 suggest a grim future for the Indian Ocean Region’s reefs as another heatwave was recorded and observations made of the start of yet another bleaching event of unknown impact. Research is key to understanding how corals adapt to rising sea surface temperatures and how we can positively impact their recovery.

Sentinel Species Research

Guano Versus El Niño

Original post:

How Bird Poop May Save Coral Reefs.

Warming sea surface temperatures have destructive effects on coral reefs, as shown during the 2015-2016 El Niño global bleaching event.

Corals rely on a highly important symbiotic relationship with an algae, called zooxanthellae. When sea temperature rises these algae can become toxic to the coral and are thus expelled, causing the coral to loose its color and appear “bleached”. Nonetheless, corals can eventually recover from bleaching events in the right circumstances and if given enough time.

Nitrogen and phosphorus occur naturally at very low levels on coral reefs, making them a notoriously nutrient-poor environment. These elements are key to the photosynthesis of the plants and algae on which coral reef ecosystems rely and act as limiting factors. To the surprise of researchers in BIOT, it seems that seabird’s guano (rich in nutrients) can provide an essential “boost” triggering coral recovery.

Indeed, seabirds are known to defecate frequently and most of this guano ends up in coral reefs ecosystems (directly or indirectly). A recent study states that this nutrient enhancement is critical for corals after a bleaching event.

The same study investigated on the coral saving guano by looking at ten islands. They found that reefs surrounding islands with a substantial seabird population had a greater growth of calcareous algae This particular seaweed serves as glue for reefs to form a barrier and is an indicator of a healthy ecosystem. Therefore, scientists suggest that guano provides optimal nitrogen to phosphorus ratios essential to reefs recovery and that we can’t replicate. Moreover, reefs surrounding healthy populations of seabirds experienced a healthier and more resilient fish population than reef with no birds.

“There is no example that is as clear cut and effective in enhancing the functioning of coral reefs in the face of climate change.”

Improving MPA Management

UN: Overfishing and Climate Change are Main Threats to Marine Biodiversity

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UN report: Ocean biodiversity in peril due to overfishing and climate change.

Human activities have significantly altered the marine environment by two-thirds, and climate change has made the situation worse.

A recent UN report paints a devastating picture of the world’s flora and fauna in terrestrial and marine environments. Indeed, the biodiversity of the world’s oceans is declining in a way unparalleled in human history. The Inter-State Science-Policy Platform for Biodiversity Ecosystem Services (IPBES) report has been written by about 150 expert authors from 50 different countries assessing global change to the health of our ecosystems over the past five decades. Only the opening summary of the report has been published so far. The full report is expected to exceed 1,500 pages and will be released later this year.

“The health of the ecosystems we and all other organisms depend on is deteriorating faster than ever before,” IPBES President Sir Robert Watson said in a statement. “We are eroding our economies, livelihoods, food security, health and the quality of life around the world.”

According to the report, climate change is an additional threat, and depending on humanity’s efforts to prevent warming, fish biomass may drop to 3-25% of current levels by the end of the century. 90% of the world’s fishers, more than 30 million people, are engaged in subsistence fishing which represents about 50% of the world’s total fishing effort.

“The ocean is facing many and various threats, and climate change and plastic pollution are getting a lot of media attention,” said Angelo O’Connor Villagomez, a senior officer at the Pew Bertarelli Marine Heritage Project. “The United Nations Report on Biodiversity reminds us,” I quote: “Direct exploitation of organisms, mainly fishing, has had the greatest negative relative impact on nature since the 1970s.”

Villagomez said he believes the fully protected marine sanctuaries are crucial to protection of marine biodiversity. About 15% of the world’s oceans are under some form of protection. In recent years, conservation efforts have resulted in the rapid spread of marine protected areas and other forms of spatial protection. Still, the International Union for Conservation of Nature recommends protecting 30% of every marine habitat to ensure the sustainability of our oceans.

These spatial prototypes have been shown to work for coastal and non-migratory species such as scallops, lobsters and reef fishes, but their impact on large migratory species such as tuna and billfishes is less evident, says Kristina Boerder, a postdoctoral fellow at Dalhousie University in Halifax, Canada

A new study by Boerder suggests that carefully designed and managed MPAs can benefit large migratory species. These ocean sanctuaries have helped rebuild the already heavily exploited fish stocks, according to Kristina, but the success of these MPAs depends on the context of each fisheries. MPAs are particularly useful when englobing known migratory routes or in “hot-spots” where various marine species aggregate to either breed, feed, or for other reasons. A better understanding of the behavior and motions of highly migratory species would enable fisheries to adjust spatial protection to species’ needs.

“We already have a lot of data and knowledge on areas such as those with significant spawning or where different species tend to congregate, but the political will to protect these areas is often absent” – Kristina Boerder

To ensure that protected areas are not just lines on a map where IUU and unsustainable fishing can operate unchecked, we need MPA managers to be equipped with the human capacity and necessary technology to carry out more efficient monitoring and management of the MPA. Well managed protected areas, fisheries and marine habitats will increase reefs resilience to climate change and may be beneficial to local fishermen, who rely on the oceans resources for economic and food security

Improving MPA Management

How can Innovative Technology Protect Wildlife from Extinction?

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How drones and AI are protecting endangered wildlife.

Melissa Schiele, a marine ecologist from Loughborough University, uses a fixed-wing UAV drone to monitor the Marine Protected Area (MPA) of BIOT, in the Indian Ocean.

With only one British vessel patrolling more than 640,000 km², the conservation of an MPA of this size is a challenge.

The main reason for the creation of this MPA is to prevent South Asian fishing vessels targeting tuna stocks and shark fins from operating in the area. However, despite restrictions illegal fishing still occurs. Prosecuting illegal fishers is extremely hard as finding definite evidence of the activities in real time is a challenge. Schiele stated: “We believe that we are the first to develop a fixed wing unit for landing in water specifically designed for marine surveillance and ecology” making their research a pioneer in the field. The use of drones could tackle this issue by obtaining photographs of the illegal fishing as well as the ships ID creating solid evidence.

The research was largely based on the BIOT ship and presented a unique set of challenges. Dynamic home positioning will bring the drone back to its starting point, which can be confusing when the launch point is a moving ship. Sea landing caused seawater to leak in the machine forcing Melissa to spend several sleepless nights fixing the drone.

“We hope that the drone will become a powerful tool in ecology and surveillance once it is fully waterproof. The aim for the drone to be a revolutionary tool for potential MPA managers in developing countries as well as marine scientists with limited funding.”

Improving MPA Management

Research is Essential to Maximise Benefits of Marine Protected Areas

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Research Key to Boosting Benefits of Large Marine Protected Areas.

Even though a lot of preparation and scientific investigation is required for the creation of marine protected areas (MPAs), even the most skilled marine scientists have limited knowledge of these remote areas.

The reason for this lack of knowledge is because previous marine conservation efforts have been focused on the minor coastal MPAs which were created before the more remote offshore MPAs, and are easier to study, monitor and protect due to their location and size. Coastal research findings can be extrapolated to offshore MPAs; however, it does not give a complete view of exactly what is happening in these regions. We can achieve such an understanding by increasing research efforts and communication, which would then inform governments and conservationists as to how to deliver meaningful ecological outcomes for these MPAs. Achieving this understanding requires extensive research and reporting and should help governments, scientists and conservationists design and implement large MPAs with strong environmental outcomes.

To identify gaps in research on large MPAs, the Pew Bertarelli Ocean Legacy project collaborated with fisheries scientists Chris Smith and Quentin Hanich of the University of Wollongong, Australia. They co-authored a paper, Large Scale Marine Protected Areas: Current status and consideration of socio-economic dimensions, summarizing the research needed to inform the management and design of large MPAs. It examines protected areas from multiple perspectives and addresses concerns from stakeholders and governments in developed and developing states. There is a broad number of areas where research could improve our MPAs, mainly in regard to migratory routes, Illegal Unregulated Unreported fisheries, climate change, traditional cultures and indigenous communities.

For example, the Papahanamukukia National Marine Monument in the Northwest Hawaii Islands was one of the first major marine protected areas in the world but was closed for commercial fishing only recently (2011). Moreover, there has been no follow up investigation into the economic or environmental impacts of this closure, its effects are unknown to stakeholders or the government. With the increasing creation of MPAs worldwide, it becomes necessary for research to be addressing such gaps to understand how large MPAs benefit both the ecosystem and its surrounding communities. The Ocean Legacy project aims to fill these gaps by working tightly with nonprofit organizations, universities and scientists. The Bertarelli Foundation’s Program in Marine Science (BPMS) is already filling these gaps with its research in the British Indian Ocean Territory.

The U.N Convention on Biological Diversity will meet in the coming year to set new global goals for the protection of global biodiversity. The UN aims to protect 10% of our oceans by 2020. With the deadline approaching, there is a chance for the UN to realign its goal with the more realistic recommendation of the IUCN for 30% of our oceans to be protected in a network of MPA by 2030. The establishment of such a network requires the implementation of many small to large MPA’s protecting all types of marine habitats and creating protected corridors along migratory routes. As stated in a landmark study “without adequate protection of species and ecosystems outside reserves, effectiveness of reserves will be severely compromised”. There is a need to look at our MPAs & fisheries as part of a whole in order to increase the sustainability of our oceans, worldwide. Habitats where marine life spawns, forages and breeds must be accordingly protected and managed with the best science and infrastructure available.

Improving MPA Management

Using Reef Sharks as an Anti-Poaching Force

Original post:

Something smells fishy: Scientists uncover illegal fishing using shark tracking devices.

Source paper: https://marine-science-cms.dev.bflexion.technology/publication/potential-detection-of-illegal-fishing-by-passive-acoustic-telemetry/?

Sharks can now take a stand against illegal fishing as marine ecologists discover that their telemetry data can inform on the presence of illegal fishing fleets.

About 95 silvertip and grey reef sharks have been acoustically tagged to measure how effective the British Indian Ocean Territory (BIOT) Marine Protected Area (MPA) is at protecting them.

A recent study shows that the synchronous loss of 15 acoustic tags in BIOT concurs with two illegal fishing ships being arrested for having 359 sharks on deck. Although its primary use was to map sharks’ movements around the reef, the acoustic tag’s data can now be used to inform on the presence of illegal fishing vessels. In spring of 2015, scientists returned to BIOT to service their acoustic receivers surrounding the archipelago, and to download the tag data from their 95 tagged sharks. To their surprise, in ten days 15 of these 95 sharks disappeared, presumably lost to illegal fishing.

Marine conservationists are increasingly using acoustic telemetry as a way to collect data from species. Scientists from Stanford University Hopkins Marine Station, ZSL and University of Western Australia have collaborated using such technology to track reef shark movement around the MPA since 2013. Acoustic tags emit a unique sound received by hydrophones which then enables their localisation. Accuracy is not optimal, locations pinpointed can still be hundreds of metres away which is why such technology (acoustic telemetry) is mostly used on more resident species than highly mobile ones.

During 2013 and 2014 and after a lengthy developmental phase and ethical review, the team tagged 47 grey reef sharks (Carcharhinus amblyrhynchos) and 48 silvertip sharks (Carcharhinus albimarginatus). These sharks were tagged and released in the BIOT MPA. The aim of this release is to track shark movements. The transmitters are usually placed on the shark’s dorsal fin. They allow a fine scale mapping of their habitat as they remain highly loyal to their reef and therefore, remain within range of the receivers. The sudden disappearance of 15 sharks is not common and most likely represents a successful illegal fishing operation.

Sharks have been particularly targeted in the last decade in BIOT and around the world. 90% of illegal fishing ship encountered in BIOT had sharks on board, making up most of the catch. This coincides with a global trend where sharks have been targeted worldwide to fuel the demand in fin soup which has now gown in popularity over Asia and is becoming cheaper and more accessible.

The team studying sharks in BIOT during spring of 2015 decided to investigate the possible relationship between illegal fishing events and the disappearance of their tags. They found that, statistically, less than 50 tags were enough to detect such illegal events and could therefore be used to detect poaching events. Nonetheless, improvements in technology are still needed, there is a need for the data from tags to be collected quicker for a more effective intervention from the BIOT Patrol vessel. In the meantime, the team on location is teaching enforcement officers where and when sharks aggregate using the data that already exists combined with historical fisheries.

“Using animals as sentinels, both to detect illegal activity and to monitor environmental conditions, extends our capabilities and reach, making us more effective stewards of our oceans.”

D. M. Tickler

Improving MPA Management

Rat Eradication on Ile Vache Marine: A Success!

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Successful Conservation Intervention in the Chagos Archipelago.

Peter Carr and his team with the Chagos Conservation Trust have proudly announced the successful eradication of rats from Ile Vache Marine.

The island sits within the British Indian Ocean Territory and therefore, within its MPA.

Invasive rats have colonized remote islands worldwide alongside human exploration since the 1800s. Ile Vache Marine is a particularly important island as its beaches are used by the two sea turtles species inhabiting BIOT, the hawksbill turtle and green sea turtle. Rats represent a significant threat to these two species populations in BIOT as they feed on their eggs and young. Additionally, they have the same impacts on the populations of native birds present on the island with an added pressure, they can eat adults. The presence of rats reduces bird populations dramatically. This affects the whole surrounding coral reef ecosystem as seabird’s guano represent an essential input of nutrients to the reef. The consequences of rat invasion on remote islands makes their eradication a sensible response plan in restoring lost populations.

The ambitious project of the Chagos Conservation Trust was to eradicate rats from the island in order to allow native species to thrive once more. For an island to be declared “rat free” a minimum period of two years of monitoring must pass to ensure no rat has survived. Therefore, in spring 2017, Peter Carr returned to the island with the hope of finding it rat free. What he found was a thriving ecosystem with native plants recovering as well as healthy invertebrate populations.

Sentinel Species Research

Changing Ratios in Hawksbill and Green Sea-Turtle Hatchlings

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Male hatchling production in sea turtles from one of the world’s largest marine protected areas, the Chagos Archipelago.

As our world becomes increasingly warm, the effects of these rising temperatures affect species worldwide.

This phenomenon can have a drastic impact on sea turtles especially, as the sex of hatchlings in the nest is determined by temperature (hotter incubation resulting in more females while cooler incubation gives more males).

This climatic disturbance has led sea turtles sex ratio in rookeries around the world to be skewed more towards females, meaning that there are now more females than male hatchlings. Should this trend continue, and coupled with other man-made pressure on the species, it could lead to female only populations and the extinction of turtle species.

A study, conducted by Dr. Nicole Esteban and the turtle team, investigated sand temperatures and their implications for hatchling sex ratios in the British Indian Ocean Territory (BIOT). The results from this study are promising. After collecting data for 2 years they found that sand temperatures were relatively cool during the nesting season of both species especially on sand shaded by vegetation. This predicts a hatchling sex ratio with slightly more males than females. This result is promising as it means that shaded nesting beaches will continue to provide a substantial number of males hatchlings into a female dominated regional population and warming world.

Sentinel Species Research

Satellite Tracking Uncovers Green Turtles’ Ability to Travel Staggering Distances

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Space tracking reveals turtles’ record-breaking ocean swim.

Core Paper:

A recent study focussing on satellite-tracking of green turtles in the Chagos Archipelago showed that turtles can travel longer distances than previously thought.

Eight green turtles were tagged while nesting on a Chagossian beach, of these eight only one did not travel to distant foraging grounds and preferred to stay in the MPA. Some individuals were tracked all the way to the east coast Africa, about 4000km away.

Green Turtles have evolved to undertake these long migrations across our oceans, when travelling they solely rely on their fat reserves. Scientists are still puzzled in the face of their navigation skills as they find small patches of seagrass in our immense oceans. This high mobility of this animal challenges the ability to protect of isolated MPAs like BIOT. Green turtles are, like most sea turtles, threatened with extinction. It is crucial to establish network of MPAs to allow these species to migrate safely as much as possible.

Unfortunately, international cooperation is needed to create these safe corridors between the already existing large MPAs. Achieving this difficult outcome will also ensure the protection of many species whom are now in dire need of it.