Boris Worm

• PhD, Biological Oceanography
• Professor (Full) at Dalhousie University

Tuna are among the world’s most valuable marine life and have long been exploited by industrial fisheries. Increasingly, tuna fishing companies have shifted from targeting free-swimming fish to using drifting fish aggregating devices (dFADs): satellite-tracked rafts that move with currents while accumulating fish below. Here, we estimate the global...

Sharks are among the most threatened groups of exploited fishes, comprising common bycatch across many fisheries. Management efforts intended to safeguard threatened species have increasingly focused on retention bans to reduce bycatch mortality. However, the population effects of such measures remain unevaluated across species. We combined availab...

Baleen whales are among the largest marine megafauna, and while mostly well-protected from direct exploitation, they are increasingly affected by vessel traffic, interactions with fisheries, and climate change. Adverse interactions, notably vessel strikes and fishing gear entanglement, often result in distress, injury, or death for these animals. I...

Climate change is a looming threat to marine life, creating an urgent need to develop climate-informed conservation strategies. The Climate Risk Index for Biodiversity was designed to assess the climate risk for marine species in a manner that supports decision-making. Yet, its regional application remains to be explored. Here, we use it to evaluat...

Despite progress in the management of assessed fish populations, many countries lag behind international commitments to restore overexploited stocks to healthy abundances. Here we use a mixed-methods positive deviance approach, also known as ‘bright spot’ analysis, to understand what drives the successful governance of exploited species by learning...

Over the past two decades, sharks have been increasingly recognized among the world’s most threatened wildlife and hence have received heightened scientific and regulatory scrutiny. Yet, the effect of protective regulations on shark fishing mortality has not been evaluated at a global scale. Here we estimate that total fishing mortality increased f...

Although the keystone species concept was conceived of over 50 years ago, contemporary efforts to synthesize related literature have been limited. Our objective was to create a list of keystone animal species identified in the literature and to examine the variation in the traits of species and the ecosystem influences they elicit. We documented 23...

Although humans have long been predators with enduring nutritive and cultural relationships with their prey, seldom have conservation ecologists considered the divergent predatory behavior of contemporary, industrialized humans. Recognizing that the number, strength and diversity of predator-prey relationships can profoundly influence biodiversity,...

This document summarizes the current conservation status of the scalloped hammerhead shark (Sphyrna lewini) in the Eastern Tropical Pacific (ETP), including knowledge gaps and conservation priorities. We used a semi-systematic literature review to compile and classify a total of 166 documents (i.e., scientific articles and grey literature) regardin...

The somatic growth of individuals governs many aspects of a species’ life history and is an important parameter in the assessment of populations. Population growth parameters are typically derived by relating the length of individuals to their age, with ages commonly estimated from growth bands formed in calcified structures such as the vertebrae o...

Unintended bycatch of depleted or vulnerable marine species is an unsolved conservation issue that undermines the sustainability of fisheries worldwide. In Canada, policy incentives to address bycatch of vulnerable species-at-risk have become more prominent in recent years. Yet bycatch risk has been difficult to quantify and mitigate, in part due t...

To successfully manage marine fisheries using an ecosystem-based approach, long-term predictions of fish stock development considering changing environmental conditions are necessary. Such predictions can be provided by end-to-end ecosystem models, which couple existing physical and biogeochemical ocean models with newly developed spatially-explici...

Climate change is impacting virtually all marine life. Adaptation strategies will require a robust understanding of the risks to species and ecosystems and how those propagate to human societies. We develop a unified and spatially explicit index to comprehensively evaluate the climate risks to marine life. Under high emissions (SSP5-8.5), almost 90...

There has been a proliferation of climate change vulnerability assessments of species, yet possibly due to their limited reproducibility, scalability, and interpretability, their operational use in applied decision-making remains paradoxically low. We use a newly developed Climate Risk Index for Biodiversity to evaluate the climate vulnerability an...

Over the past 4 decades there has been a growing concern for the conservation status of elasmobranchs (sharks and rays). In 2002, the first elasmobranch species were added to Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Less than 20 yr later, there were 39 species on Appendix II and 5 o...

Populations of blue whales were heavily depleted across the globe by industrial whaling and are still considered globally endangered today. In the Northwest Atlantic, an estimated 400–600 individuals remain, but these numbers are highly uncertain. Ship strikes, fishing gear entanglement, and marine debris are thought to be leading causes of contemp...

Concerns over overexploitation have fueled an ongoing debate on the current state and future prospects of global capture fisheries, associated threats to marine biodiversity, and declining yields available for human consumption. Management reforms have aimed to reduce fishing pressure and recover depleted stocks to biomass and exploitation rates th...

In response to fisheries declines and delayed population recoveries, many management agencies globally are integrating alternative strategies that incorporate precautionary and ecosystem considerations, increasingly focusing on climate variability and change. Here, we quantitatively evaluate how these themes have been incorporated into the science...

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

A Correction to this paper has been published: https://doi.org/10.1038/s41586-021-03496-1.

The ocean contains unique biodiversity, provides valuable food resources and is a major sink for anthropogenic carbon. Marine protected areas (MPAs) are an effective tool for restoring ocean biodiversity and ecosystem services1,2, but at present only 2.7% of the ocean is highly protected³. This low level of ocean protection is due largely to confli...

Ambient temperature is a leading environmental factor determining the distribution and diversity of life in the oceans. Hence, climate change is fundamentally changing marine biodiversity on a global scale and will continue to do so into the future. Here, we review observed and predicted effects of climate change on the diversity of marine species....

Leatherback sea turtles (Dermochelys coriacea) migrate to temperate Canadian Atlantic waters to feed on gelatinous zooplankton (‘jellyfish’) every summer. However, the spatio-temporal connection between predator foraging and prey-field dynamics has not been studied at the large scales over which these migratory animals occur. We use 8903 tows of gr...

Future climate impacts and their consequences are increasingly being explored using multi-model ensembles that average across individual model projections. Here we develop a statistical framework that integrates projections from coupled ecosystem and earth-system models to evaluate significance and uncertainty in marine animal biomass changes over...

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...

North Atlantic right whales (NARW) are one of the most endangered marine animals with a global population of ~400 individuals left. Recent climate-driven shifts in distribution have significantly increased their mortality risk from human activities. After twelve NARWs died in the Gulf of St. Lawrence in 2017 from fishing gear entanglement and ship...

Climate change is increasingly impacting marine protected areas (MPAs) and MPA networks, yet adaptation strategies are rarely incorporated into MPA design and management plans according to the primary scientific literature. Here, we review the state of knowledge for adapting existing and future MPAs to climate change and synthesize case studies (n...

Plankton communities account for at least half of global primary production and play a key role in the global carbon cycle. Warming and acidification may alter the interaction chains in these communities from the bottom and top of the food web. Yet, the relative importance of these potentially complex interactions has not yet been quantified. Here,...

The impacts of climate change and the socioecological challenges they present are ubiquitous and increasingly severe. Practical efforts to operationalize climate-responsive design and management in the global network of marine protected areas (MPAs) are required to ensure long-term effectiveness for safeguarding marine biodiversity and ecosystem se...

Two timely, urgent books offer different takes on the state of the seas. Boris Worm lauds both. Two timely, urgent books offer different takes on the state of the seas. Boris Worm lauds both.

Harvesting wild seaweeds has a long history and is still relevant today, even though aquaculture now supplies >96% of global seaweed production. Current wild harvests mostly target canopy-forming kelp, rockweed and red macroalgae that provide important ecosystem roles, including primary production, carbon storage, nutrient cycling, habitat provisio...

While the physical dimensions of climate change are now routinely assessed through multimodel intercomparisons, projected impacts on the global ocean ecosystem generally rely on individual models with a specific set of assumptions. To address these single-model limitations, we present standardized ensemble projections from six global marine ecosyst...

Human beings are the dominant top predator in the marine ecosystem. Throughout most of the global ocean this predation is carried out by industrial fishing vessels, that can now be observed in unprecedented detail via satellite monitoring of Automatic Identification System (AIS) messages. The spatial and temporal distribution of this fishing effort...

Spatial protection measures have become ubiquitous in fisheries management and marine conservation. Implemented for diverse objectives from stock rebuilding to biodiversity protection and ecosystem management, spatial measures range from temporary fisheries closures to marine protected areas with varying levels of protection. Ecological and economi...

Many of the world's vertebrates have experienced large population and geographic range declines due to anthropogenic threats that put them at risk of extinction. The largest vertebrates, defined as megafauna, are especially vulnerable. We analyzed how human activities are impacting the conservation status of megafauna within six classes: mammals, r...

Not as advertised Marine protected areas (MPAs) have increasingly designated globally, with an associated advertised percentage of area protected. However, recent research has made it clear that many MPAs are not actually protecting marine biodiversity. Dureuil et al. focused on European MPAs and found that trawling, one of the most damaging types...

Amoroso et al. demonstrate the power of our data by estimating the high-resolution trawling footprint on seafloor habitat. Yet we argue that a coarser grid is required to understand full ecosystem impacts. Vessel tracking data allow us to estimate the footprint of human activities across a variety of scales, and the proper scale depends on the spec...

International interest in the protection and sustainable use of high seas biodiversity has grown in recent years. There is an opportunity for new technologies to enable improvements in management of these areas beyond national jurisdiction. We explore the spatial ecology and drivers of the global distribution of the high seas long-line fishing flee...

A major challenge in global fisheries is posed by transshipment of catch at sea from fishing vessels to refrigerated cargo vessels, which can obscure the origin of the catch and mask illicit practices. Transshipment remains poorly quantified at a global scale, as much of it is thought to occur outside of national waters. We used Automatic Identific...

This chapter considers the driving factors that may cause global patterns of biodiversity to exist. The goal is to confront published hypotheses about putative drivers of diversity with comprehensive empirical information on the environmental predictors of diversity on land and in the oceans. It argues that the diversity of life on land is primaril...

The previous chapter developed a global theory of biodiversity incorporating gradients in ambient temperature and habitat area or productivity. It showed that a metacommunity model implementation of the theory can reproduce first-order patterns of declining species richness from the tropics to the poles in an idealized cylindrical ocean. This chapt...

This chapter explores the following question: How can our knowledge of global biodiversity patterns and our understanding of underlying processes and drivers help us to apprehend, project, and reverse the trajectory of large-scale biodiversity loss? It examines global richness patterns and biodiversity hotspots on land and in the sea together. It l...

This chapter develops a body of theory to capture and test the key processes governing the global distribution of biodiversity. From this theory, it devises a spatial metacommunity model that enables the reconstruction of documented patterns of species richness from first principles and the prediction of their major features. The chapter starts wit...

This chapter summarizes and synthesizes known biodiversity patterns, and analyzes them for congruency over space and time. The discussion is limited to macroecological patterns at continental to global scales (thousands of km). The chapter also focuses on the simplest measure of biodiversity—namely, species richness. The discussions cover marine co...

The number of species found at a given point on the planet varies by orders of magnitude, yet large-scale gradients in biodiversity appear to follow some very general patterns. Little mechanistic theory has been formulated to explain the emergence of observed gradients of biodiversity both on land and in the oceans. Based on a comprehensive empiric...

More than half the fish in the sea As the human population has grown in recent decades, our dependence on ocean-supplied protein has rapidly increased. Kroodsma et al. took advantage of the automatic identification system installed on all industrial fishing vessels to map and quantify fishing efforts across the world (see the Perspective by Polocza...

The largest protected areas of any kind have all recently been established in the ocean. Since 2012, 5 protected areas that exceed 1 million km² in size have been created, mostly in remote oceanic areas. The potential conservation and fisheries benefits of such reserves have been debated in the public, the media, and the scientific literature. Litt...

Synthetic organic polymers-or plastics-did not enter widespread use until the 1950s. By 2015, global production had increased to 322 million metric tons (Mt) year⁻¹, which approaches the total weight of the human population produced in plastic every year. Approximately half is used for packaging and other disposables, 40% of plastic waste is not ac...

There is growing interest in the integration of macroecology and palaeoecology towards a better understanding of past, present, and anticipated future biodiversity dynamics. However, the empirical basis for this integration has thus far been limited. Here we review prospects for a macroecology-palaeoecology integration in biodiversity analyses with...

Seasonal cycles of primary production (phenology) critically influence biogeochemical cycles, ecosystem structure and climate. In the oceans, primary production is dominated by microbial phytoplankton that drift with currents, and show rapid turnover and chaotic dynamics, factors that have hindered understanding of their phenology. We used all avai...

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...

Rebuilding depleted fish stocks is an international policy goal and a 2020 Aichi target under the Convention on Biological Diversity. However, stock productivity may shift with future climate change, with unknown consequences for sustainable harvesting, biomass targets and recovery timelines. Here we develop a stochastic modelling framework to char...

Supplementary Figures, Supplementary Table and Supplementary References

Aim While geographical patterns of species richness are reasonably well explored for single well‐studied taxa, less is known about aggregate patterns of total richness for major biomes and their environmental correlates. Here we analyse continental‐scale aggregate patterns of macrofaunal diversity for sandy beaches, a dominant habitat along the Atl...

To successfully manage marine fisheries using an ecosystem-based approach, long-term predictions of fish stock development considering changing environmental conditions are necessary. Such predictions can be provided by end-to-end ecosystem models, which couple existing physical and biogeochemical ocean models with newly developed spatially-explici...

Marine protected areas are being implemented at an accelerating pace, and hold promise for restoring damaged ecosystems. But glaring shortfalls in staffing and funding often lead to suboptimal outcomes.

Ambient temperature is very likely the most important environmental factor determining the distribution and diversity of life in the oceans. Hence, climate change is expected to alter marine biodiversity on a global scale. Here we review observed and predicted effects of climate change on the diversity of marine species. Overall, an increasing numb...

As society strives to transition towards more sustainable development pathways, it is important to properly conceptualize the link between biodiversity (i.e. genes, traits, species and other dimensions) and human well-being (HWB; i.e. health, wealth, security and other dimensions). Here, we explore how published conceptual frameworks consider the e...

Here, we identify the extant species of marine megafauna (>45 kg maximum reported mass), provide a conceptual template for the ways in which these species influence the structure and function of ocean ecosystems, and review the published evidence for such influences. Ecological influences of more than 90% of the 338 known species of extant ocean me...

There is an error in the caption of Table 2. Specifically, the descriptions of the results for Sensitivity and Specificity are switched (sensitivity linked to non-fishing detection instead of fishing detection and vice versa for specificity). Please see the corrected Table 2 and caption here. (table presented). © 2016 de Souza et al. This is an ope...

A key challenge in contemporary ecology and conservation is the accurate tracking of the spatial distribution of various human impacts, such as fishing. While coastal fisheries in national waters are closely monitored in some countries, existing maps of fishing effort elsewhere are fraught with uncertainty, especially in remote areas and the High S...

Ecologists have identified numerous keystone species, defined as organisms that have outsized ecological impacts relative to their biomass. Here we identify human beings as a higher-order or ‘hyperkeystone’ species that drives complex interaction chains by affecting other keystone actors across different habitats. Strong indirect effects and a glob...

The deep ocean is the largest and least-explored ecosystem on Earth, and a uniquely energy-poor environment. The distribution, drivers and origins of deep-sea biodiversity remain unknown at global scales. Here we analyse a database of more than 165,000 distribution records of Ophiuroidea (brittle stars), a dominant component of sea-floor fauna, and...

Oceans cover 71% of Earth’s surface and support an estimated 3 billion people with food and vital micronutrients (1). Consequently, the fate of the ocean and its living resources is a first-order question in ecology and environmental science (2). In this context, a 2006 panel of ecologists and fisheries scientists empirically charted the consequenc...

The ocean remains the least observed part of our planet. This deficiency was made obvious by two recent developments in ocean governance: the emerging global movement to create massive marine protected areas (MPAs) ( 1 ) and a new commitment by the United Nations (UN) to develop a legally binding treaty to better manage high-seas biodiversity ( 2 )...

Szuwalski (1) suggests that our meta-analysis of global changes in fish stock recruitment capacity (2) should be weighted according to the biomass or catch of individual stocks, instead of weighting each stock equally. Although informative, it is important to recognize that such a perspective heavily biases any global trends in favor of a few large...

Aim Latitudinal gradients of species richness represent Earth's first‐order biodiversity pattern. Most species groups display a near‐monotonic decline in richness from the equator to the poles, yet there exists little mechanistic theory to derive such patterns from first principles. Here we integrate two key advances – neutral theory and the metabo...

Significance Marine fish stocks play an important role in marine ecosystems and provide a source of protein for billions of people worldwide. Recent environmental changes have affected the distribution of many stocks, but it is yet unclear whether their productivity is affected as well. We show that recruitment capacity (the ability of stocks to pr...

Approximately 25% of globally reported shark catches occur in Atlantic pelagic longline fisheries. Strong declines in shark populations have been detected in the North Atlantic while in the South Atlantic the situation is less clear, although fishing effort has been increasing in this region over the last 50 years. Here we provide a synthesis of in...

This study addresses the inherent uncertainty when estimating growth from limited mark–recapture information. A selection procedure was developed utilizing 18 competing growth estimation methods. The optimal method for a given data set was identified by simulating the length at capture and recapture under different scenarios of measurement error an...

In 1962, Rachel Carson made history when she published her seminal book Silent Spring (1), which cataloged the toxic effects of a ubiquitous, but seemingly harmless chemical [dichlorodiphenyltrichloroethane (DDT)]. This work almost single-handedly brought chemical pollution into public consciousness and ignited a global environmental movement. Cars...

There is growing evidence that average global phytoplankton concentrations have been changing over the past century, yet published trajectories of change are highly divergent. Here, we review and analyze 115 published phytoplankton trend estimates originating from a wide variety of sampling instruments to explore the underlying patterns and ecologi...

Modern humans evolved as cooperative hunter-gatherers whose cultural and technological evolution enabled them to slay prey much larger than themselves, across many species groups. One might think that those hunting skills have faded since the advent of agriculture and animal husbandry almost 10,000 years ago. Yet, as Darimont et al. show in a globa...

A key question in ecology is under which conditions ecosystem structure tends to be controlled by resource availability vs. consumer pressure. Several hypotheses derived from theory, experiments and observational field studies have been advanced, yet a unified explanation remains elusive. Here, we identify common predictors of trophic control in a...

Exploited marine populations are thought to be regulated by the effects of fishing, species interactions and climate. Yet, it is unclear how these forces interact and vary across a species’ range. We conducted a meta‐analysis of American lobster ( H omarus americanus ) abundance data throughout the entirety of the species’ range, testing competing...

Understanding and reducing the incidence of accidental bycatch, particularly for vulnerable species such as sharks, is a major challenge for contemporary fisheries management. Here we establish integrated nested Laplace approximations (INLA) and stochastic partial differential equations (SPDE) as two powerful tools for modelling patterns of bycatch...

Background/Question/Methods The relative strength and importance of consumer versus resource control within and across marine ecosystems has been intensively investigated using empirical, experimental, and theoretical approaches for over a century. This research has led to numerous interesting discoveries, yet a unified explanation for spatial an...

Atlantic Ocean fishing fleets report approximately 25% of global shark landings. The level of these catches is likely an underestimation of the total fishing mortality affecting sharks in the area due to unreported catches related to discards and finning. Notwithstanding, strong declines of shark populations have been detected in the North Atlantic...

Tuna are among the most ubiquitous oceanic predators, and range globally from the equator to temperate regions (0 to 55 degrees latitude). While the distribution of adult fish has been mapped from fishing records, the extent of tuna spawning and larval habitats is less well understood. We compiled and analyzed data on the global distributions of la...

Ocean warming has been implicated in the observed decline of oceanic phytoplankton biomass. Some studies suggest a physical pathway of warming via stratification and nutrient flux, and others a biological effect on plankton metabolic rates; yet the relative strength and possible interaction of these mechanisms remains unknown. Here, we implement pr...

Productivity is a central determinant of population dynamics with consequences for population viability, resilience to exploitation, and extinction. In fish, the strength of a cohort is typically established during early life stages. Traditional approaches to measuring productivity do not allow for interannual variation in the maximum reproductive...

Organisms are expected to adapt or move in response to climate change, but observed distribution shifts span a wide range of directions and rates. Explanations often emphasize biological distinctions among species, but general mechanisms have been elusive. We tested an alternative hypothesis: that differences in climate velocity—the rate and direct...