Callum M Roberts

University of Exeter | UoE · College of Life and Environmental Sciences

The long-term provision of ocean ecosystem services de- pends on healthy ecosystems and effective sustainable man- agement. Understanding public opinion about marine and coastal ecosystems is important to guide decision-making and inform specific actions. However, available data on pub- lic perceptions on the interlinked effects of climate change,...

The world is struggling to limit greenhouse gas emissions and reduce the human footprint on nature. We therefore urgently need to think about how to achieve more with actions to address mounting challenges for human health and wellbeing from biodiversity loss, climate change effects, and unsustainable economic and social development. Nature-based S...

We review the current knowledge of the biodiversity of the ocean as well as the levels of decline and threat for species and habitats. The lack of understanding of the distribution of life in the ocean is identified as a significant barrier to restoring its biodiversity and health. We explore why the science of taxonomy has failed to deliver knowle...

Subtidal seabed sediments are one of the planet's biggest organic carbon stores, but have been poorly considered in nature‐based climate change mitigation. Protection of the seabed is predominantly through establishment of marine protected area (MPA) networks, but their emphasis on biodiversity may limit their carbon value. The United Kingdom has o...

Mobile bottom fishing using trawls and dredges may cause significant reductions in seabed sediment organic carbon stores, limiting the oceanic carbon sink. Although uncertainties remain about the fate of disturbed carbon, protecting the most important and highly disturbed seabed carbon sinks for climate change mitigation represents a sensible preca...

Protecting areas of seabed sediment would appear to be an important climate mitigation strategy, however carbon has not been considered in national management plans. Using spatial analyses we show, in the UK Exclusive Economic Zone (EEZ), high potential organic carbon loss due to mobile bottom fishing is likely to be geographically restricted. Curr...

Subtidal marine sediments are one of the planet's primary carbon stores and strongly influence the oceanic sink for atmospheric CO2. By far the most widespread human activity occurring on the seabed is bottom trawling/dredging for fish and shellfish. A global first‐order estimate suggested mobile demersal fishing activities may cause 0.16–0.4 Gt of...

Of all the interconnected threats facing the planet, the top two are the climate and the biodiversity crises. Neither problem will be solved if we ignore the ocean. To turn the tide in favour of humanity and a habitable planet, we need to recognize and better value the fundamental role that the ocean plays in the earth system, and prioritize the ur...

Consistency in conservation Marine protected areas (MPAs) are now well established globally as tools for conservation, for enhancing marine biodiversity, and for promoting sustainable fisheries. That said, which regions are labeled as MPAs varies substantially, from those that full protect marine species and prohibit human extraction to those that...

Subtidal marine sediments are one of the planet's primary carbon stores and strongly influence the oceanic sink for atmospheric CO2. By far the most pervasive human activity occurring on the seabed is bottom trawling and dredging for fish and shellfish. A global first-order estimate suggested mobile demersal fishing activities may cause 160-400 Mt...

A Correction to this paper has been published: https://doi.org/10.1038/s41586-021-03271-2.

Caribbean reefs have experienced unprecedented changes in the past four decades. Of great concern is the perceived widespread shift from coral to macroalgal dominance and the question of whether it represents a new, stable equilibrium for coral-reef communities. The primary causes of the shift—grazing pressure (top-down), nutrient loading (bottom-u...

The High Level Panel for Sustainable Ocean Economy (https://oceanpanel.org/) has commissioned a series of “Blue Papers” to explore pressing challenges at the nexus of the ocean and the economy. This paper is part of a series of 16 papers to be published between November 2019 and October 2020. It addresses how multiple human impacts will impact bi...

Sustainable Development Goal 14 of the United Nations aims to “conserve and sustainably use the oceans, seas and marine resources for sustainable development”. Achieving this goal will require rebuilding the marine life-support systems that deliver the many benefits that society receives from a healthy ocean. Here we document the recovery of marine...

Areas beyond national jurisdiction (ABNJ) constitute 61% of the world’s oceans and are collectively managed by countries under the United Nations Convention on the Law of the Sea (UNCLOS). Growing concern regarding the deteriorating state of the oceans and ineffective management of ABNJ has resulted in negotiations to develop an international legal...

Nations of the world have, to date, pursued nature protection and climate change mitigation and adaptation policies separately. Both efforts have failed to achieve the scale of action needed to halt biodiversity loss or mitigate climate change. We argue that success can be achieved by aligning targets for biodiversity protection with the habitat pr...

• In 2016, the UK government announced plans for a large‐scale Marine Protected Area around Ascension Island, a UK Overseas Territory in the South Atlantic. • To improve baselines for marine life to support ambitious conservation and assess change over time, archives were searched for historical accounts of wildlife from Ascension's discovery in 15...

The Firth of Clyde, on the west coast of Scotland, was once one of the most productive fishing grounds in Europe. However, successive decades of poor management and overfishing led to a dramatic loss of biodiversity and the collapse of finfish fisheries. In response, concerned local residents on the Isle of Arran, which lies in the middle of the Cl...

Current international agreements call for protecting 10% of marine and coastal waters by 2020, with the intention of increasing that target to 30% by 2030. With 24% of its territorial waters protected, the UK falls short of the new expected target. As well as quantitative targets, qualitative criteria have been internationally agreed for protected...

Manta ray tourism is estimated to contribute US$ 140 million annually to the global economy. The multitudes of tourists potentially disturb the animals, yet the effect of human behaviour on feeding manta rays has not been quantified. Using videos collected at feeding sites in the Maldives, we found that only 44% of observed human-manta interactions...

The ocean crisis is urgent and central to human wellbeing and life on Earth; past and current activities are damaging the planet's main life support system for future generations. We are witnessing an increase in ocean heat, disturbance, acidification, bio‐invasions and nutrients, and reducing oxygen levels. Several of these act like ratchets: once...

Caribbean reefs have experienced unprecedented changes in the past four decades. Of great concern is the perceived widespread shift from coral to macroalgal dominance and the question of whether it represents a new, stable equilibrium for coral-reef communities. The primary causes of the shift -- grazing pressure (top-down), nutrient loading (botto...

Understanding the evidence base and identifying threats to the marine environment is critical to ensure cost-effective management and to identify priorities for future research. The United Kingdom (UK) government is responsible for approximately 2% of the world’s oceans, most of which belongs to its 14 Overseas Territories (UKOTs). Containing biodi...

Mangroves are one of the most productive ecosystems in the world, sustaining millions of coastal livelihoods. However, their area of occurrence has been greatly reduced over the last century. In this study, we identify potential drivers of land use and land cover change adjacent to mangroves on the Pacific shorelines of Colombia, Panama and Costa R...

Coastal nations have embarked on a rapid program of marine protected area (MPA) establishment, incentivised by the approaching 2020 deadline of United Nations global marine protection targets. Alongside, efforts are underway to extend protection into areas beyond national jurisdiction through a new international legally binding instrument. These de...

The aim of this 14 year study was to elucidate the entire courtship and mating behaviour of manta rays Mobula alfredi and M. birostris using behavioural observations, video and photographic records. From 2003 to 2016, over 11 000 surveys were undertaken at known manta ray aggregation sites in the Maldives to record any observed manta rays reproduct...

The United Nations’ target for global ocean protection is 10% of the ocean in Marine Protected Areas (MPAs) by 2020. There has been remarkable progress in the last decade, and some organizations claim that 7% of the ocean is already protected and that we will exceed the 10% target by 2020. However, currently only 3.6% of the ocean is in implemented...

Designated large-scale marine protected areas (LSMPAs, 100,000 or more square kilometers) constitute over two-thirds of the approximately 6.6% of the ocean and approximately 14.5% of the exclusive economic zones within marine protected areas. Although LSMPAs have received support among scientists and conservation bodies for wilderness protection, r...

The Pacific coast of Colombia has some of the most extensive mangrove forests in South America. As an isolated region and one of the country's poorest, coastal communities rely on fishing as a main source of animal protein and income. In an attempt to reverse declining trends of fisheries resources, in 2008, an Exclusive Zone of Artisanal Fishing c...

Areas beyond national jurisdiction (ABNJ) lie outside the 200 nautical mile limits of national sovereignty and cover 58% of the ocean surface. Global conservation agreements recognize biodiversity loss in ABNJ and aim to protect ≥10% of oceans in marine protected areas (MPAs) by 2020. However, limited mechanisms to create MPAs in ABNJ currently exi...

In O'Leary et al. (2016), we undertook a quantitative synthesis (rather than a true statistical meta-analysis) of research to consider how much of the sea should be protected to achieve various conservation and management goals. We aimed to provide perspective on the appropriateness of global marine protected area coverage targets, particularly the...

Strong decreases in greenhouse gas emissions are required to meet the reduction trajectory resolved within the 2015 Paris Agreement. However, even these decreases will not avert serious stress and damage to life on Earth, and additional steps are needed to boost the resilience of ecosystems, safeguard their wildlife, and protect their capacity to s...

The Dogger Bank is a subtidal hill in the North Sea that is a candidate Special Area of Conservation under the EU Habitats Directive in UK waters. Historical records indicate that the Bank has been subject to human exploitation from before the 16th century but conservation objectives have been developed using recent survey data. This has the potent...

This study investigated the effects of a community-led temperate marine reserve in Lamlash Bay, Firth of Clyde, Scotland, on commercially important populations of European lobster (Homarus gammarus), brown crab (Cancer pagurus), and velvet swimming crabs (Necora puber). Potting surveys conducted over 4 years revealed significantly higher catch per...

The Cultural and Biological Significance of the proposed expansion for the Papahānaumokuākea Marine National Monument

Public perception research evaluating awareness and attitudes towards marine protection is limited in the United Kingdom (UK) and worldwide. Given public opinion can help drive policy and affect its successful delivery we conducted nationwide surveys in 2005, 2010 and 2015 to assess public knowledge of UK (England, Scotland and Wales) sea 'health'...

Cape Verde in the Eastern Atlantic is typical of many island groups in supporting a wealth of endemic species both terrestrial and marine. Marine gastropod molluscs of the genus Conus, commonly known as cone snails, occur in coastal tropical waters throughout the globe, but in Cape Verde their endemism reaches its apogee with 53 out of 56 species o...

From native pre-Columbian subsistence economies to the modern global economy, mangroves have played an important role providing goods and services to human societies for millennia. More than 90% of the world’s mangroves are located in developing countries, where rates of destruction are increasing rapidly and on large scales. In order to design eff...

The UN's globally adopted Convention on Biological Diversity coverage target for marine protected areas (MPAs) is ≥10% by 2020. In 2014 the World Parks Congress recommended increasing this to ≥30%. We reviewed 144 studies to assess whether the UN target is adequate to achieve, maximise or optimise six environmental and/or socio-economic objectives....

The extent to which Marine Protected Areas (MPAs) benefit corals is contentious. On one hand, MPAs could enhance coral growth and survival through increases in herbivory within their borders; on the other, they are unlikely to prevent disturbances, such as terrestrial runoff, that originate outside their boundaries. We examined the effect of spatia...

Ecological data sets rarely extend back more than a few decades, limiting our understanding of environmental change and its drivers. Marine historical ecology has played a critical role in filling these data gaps by illuminating the magnitude and rate of ongoing changes in marine ecosystems. Yet despite a growing body of knowledge, historical insig...

This study investigated the effects of a newly established, fully protected marine reserve on benthic habitats and two commercially valuable species of scallop in Lamlash Bay, Isle of Arran, United Kingdom. Annual dive surveys from 2010 to 2013 showed the abundance of juvenile scallops to be significantly greater within the marine reserve than outs...

Fishing takes place in the high seas and Exclusive Economic Zones (EEZs) of maritime countries. Closing the former to fishing has recently been proposed in the literature and is currently an issue of debate in various international fora. We determine the degree of overlap between fish caught in these two areas of the ocean, examine how global catch...

Winners and losers in a world where the high seas is closed to fishing

Many over-exploited marine ecosystems worldwide have lost their natural populations of large predatory finfish and have become dominated by crustaceans and other invertebrates. Controversially, some of these simplified ecosystems have gone on to support highly successful invertebrate fisheries capable of generating more economic value than the fish...

An age-old conflict around a seemingly simple question has resurfaced: why do we conserve nature? Contention around this issue has come and gone many times, but in the past several years we believe that it has reappeared as an increasingly acrimonious debate between, in essence, those who argue that nature should be protected for its own sake (intr...

The International Union for Conservation of Nature Red List of Endangered Species employs a robust, standardised approach to assess extinction threat focussed on taxa approaching an end-point in population decline. Used alone, we argue this enforces a reactive approach to conservation. Species not assessed as threatened but which occur predominantl...

In recent years, marine protected areas have been "super-sized". At first glance, this seems a gift to marine conservation. Yet, the new wave of very large marine protected areas ("VLMPAs") have faced criticism from the scientific community. In this article we examine the merits and the criticisms of VLMPAS, and consider whether they provide a much...

As the wild blue yonder beckons and labs and classrooms empty, Nature's regular reviewers share their holiday reads.

Background A principal function of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) is to “perform regular and timely assessments of knowledge on biodiversity.” In December 2013, its second plenary session approved a program to begin a global assessment in 2015. The Convention on Biological Diversity (CBD...

Marine molluscs represent an estimated 23% of all extant marine taxa, but research into their conservation status has so far failed to reflect this importance, with minimal inclusion on the authoritative Red List of the International Union for the Conservation of Nature (IUCN). We assessed the status of all 632 valid species of the tropical marine...

Marine inshore communities, including biogenic habitats have undergone dramatic changes as a result of exploitation, pollution, land-use changes and introduced species. The Firth of Forth on the east coast of Scotland was once home to the most important oyster (Ostrea edulis Linnaeus, 1758) beds in Scotland. 19th and early 20th century fisheries sc...

Callum Roberts enjoys a celebration of the oceans and their largest denizens.

Bottom trawling (nets towed along the seabed) spread around the British Isles from the 1820s, yet the collection of national fisheries statistics did not begin until 1886. Consequently, analysis of the impacts of trawling on fish stocks and habitats during this early period is difficult, yet without this information, we risk underestimating the ext...

To improve sustainability of ocean ecosystems, implementation of existing commitments should be prioritized.

A new study of the Great Barrier Reef proves a 100-year old conjecture correct: marine reserves do replenish populations in surrounding fishing grounds, while modern reserve networking theory is validated by exchange of offspring of animals among protected areas.

Marine protected areas (MPAs) are increasingly being established to protect and rebuild coastal and marine ecosystems. However, while the high seas are increasingly subject to exploitation, globally few MPAs exist in areas beyond national jurisdiction. In 2010 a substantial step forward was made in the protection of high seas ecosystems with 286,20...