I am a quantitative and computational marine ecologist specialized in research synthesis. My scientific work is on marine conservation, fishery sciences, population dynamics, and quantitative ecology with a special interest in sharks and rays. I combine ecology, statistical modeling, and computer science to approach questions on animal abundance and distribution, species interactions, large marine predators, top-down control, structure and functioning of large marine ecosystems.
Basic Life Science Research Associate, Biology
PhD, Dalhousie University, Marine Ecology (2010)
Master of Science, Polytechnic University of Marche, Marine Biology (2003)
The importance of migratory connectivity for global ocean policy.
Proceedings. Biological sciences
2019; 286 (1911): 20191472
The distributions of migratory species in the ocean span local, national and international jurisdictions. Across these ecologically interconnected regions, migratory marine species interact with anthropogenic stressors throughout their lives. Migratory connectivity, the geographical linking of individuals and populations throughout their migratory cycles, influences how spatial and temporal dynamics of stressors affect migratory animals and scale up to influence population abundance, distribution and species persistence. Population declines of many migratory marine species have led to calls for connectivity knowledge, especially insights from animal tracking studies, to be more systematically and synthetically incorporated into decision-making. Inclusion of migratory connectivity in the design of conservation and management measures is critical to ensure they are appropriate for the level of risk associated with various degrees of connectivity. Three mechanisms exist to incorporate migratory connectivity into international marine policy which guides conservation implementation: site-selection criteria, network design criteria and policy recommendations. Here, we review the concept of migratory connectivity and its use in international policy, and describe the Migratory Connectivity in the Ocean system, a migratory connectivity evidence-base for the ocean. We propose that without such collaboration focused on migratory connectivity, efforts to effectively conserve these critical species across jurisdictions will have limited effect.
View details for DOI 10.1098/rspb.2019.1472
View details for PubMedID 31551061
- Estimating Space Use of Mobile Fishes in a Large Marine Protected Area With Methodological Considerations in Acoustic Array Design FRONTIERS IN MARINE SCIENCE 2019; 6
Killer whales redistribute white shark foraging pressure on seals.
2019; 9 (1): 6153
Predatory behavior and top-down effects in marine ecosystems are well-described, however, intraguild interactions among co-occurring marine top predators remain less understood, but can have far reaching ecological implications. Killer whales and white sharks are prominent upper trophic level predators with highly-overlapping niches, yet their ecological interactions and subsequent effects have remained obscure. Using long-term electronic tagging and survey data we reveal rare and cryptic interactions between these predators at a shared foraging site, Southeast Farallon Island (SEFI). In multiple instances, brief visits from killer whales displaced white sharks from SEFI, disrupting shark feeding behavior for extended periods at this aggregation site. As a result, annual predations of pinnipeds by white sharks at SEFI were negatively correlated with close encounters with killer whales. Tagged white sharks relocated to other aggregation sites, creating detectable increases in white shark density at Ano Nuevo Island. This work highlights the importance of risk effects and intraguild relationships among top ocean predators and the value of long-term data sets revealing these consequential, albeit infrequent, ecological interactions.
View details for PubMedID 30992478
- Killer whales redistribute white shark foraging pressure on seals SCIENTIFIC REPORTS 2019; 9
- Predicted hotspots of overlap between highly migratory fishes and industrial fishing fleets in the northeast Pacific SCIENCE ADVANCES 2019; 5 (3)
Predicted hotspots of overlap between highly migratory fishes and industrial fishing fleets in the northeast Pacific.
2019; 5 (3): eaau3761
Many species of sharks and some tunas are threatened by overexploitation, yet the degree of overlap between industrial fisheries and pelagic fishes remains poorly understood. Using satellite tracks from 933 industrial fishing vessels and predictive habitat models from 876 electronic tags deployed on seven shark and tuna species, we developed fishing effort maps across the northeast Pacific Ocean and assessed overlap with core habitats of pelagic fishes. Up to 35% of species' core habitats overlapped with fishing effort. We identified overlap hotspots along the North American shelf, the equatorial Pacific, and the subtropical gyre. Results indicate where species require international conservation efforts and effective management within national waters. Only five national fleets (Mexico, Taiwan, China, Japan, and the United States) account for >90% of overlap with core habitats of our focal sharks and tunas on the high seas. These results inform global negotiations to achieve sustainability on the high seas.
View details for PubMedID 30891492
Global spatial risk assessment of sharks under the footprint of fisheries.
Effective ocean management and conservation of highly migratory species depends on resolving overlap between animal movements and distributions and fishing effort. Yet, this information is lacking at a global scale. Here we show, using a big-data approach combining satellite-tracked movements of pelagic sharks and global fishing fleets, that 24% of the mean monthly space used by sharks falls under the footprint of pelagic longline fisheries. Space use hotspots of commercially valuable sharks and of internationally protected species had the highest overlap with longlines (up to 76% and 64%, respectively) and were also associated with significant increases in fishing effort. We conclude that pelagic sharks have limited spatial refuge from current levels of high-seas fishing effort. Results demonstrate an urgent need for conservation and management measures at high-seas shark hotspots and highlight the potential of simultaneous satellite surveillance of megafauna and fishers as a tool for near-real time, dynamic management.
View details for DOI 10.1038/s41586-019-1444-4
View details for PubMedID 31340216
- Sea pens in the Mediterranean Sea: habitat suitability and opportunities for ecosystem recovery (vol 75, pg 1722, 2018) ICES JOURNAL OF MARINE SCIENCE 2018; 75 (6): 2289–91
- Leveraging vessel traffic data and a temporary fishing closure to inform marine management FRONTIERS IN ECOLOGY AND THE ENVIRONMENT 2018; 16 (8): 440–45
Response to Comment on "Tracking the global footprint of fisheries"
2018; 361 (6404)
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 specific impact being investigated.
View details for PubMedID 30139846
Shark baselines and the conservation role of remote coral reef ecosystems
2018; 4 (3): eaaq0333
Scientific monitoring has recorded only a recent fraction of the oceans' alteration history. This biases our understanding of marine ecosystems. Remote coral reef ecosystems are often considered pristine because of high shark abundance. However, given the long history and global nature of fishing, sharks' vulnerability, and the ecological consequences of shark declines, these states may not be natural. In the Chagos archipelago, one of the remotest coral reef systems on the planet, protected by a very large marine reserve, we integrated disparate fisheries and scientific survey data to reconstruct baselines and long-term population trajectories of two dominant sharks. In 2012, we estimated 571,310 gray reef and 31,693 silvertip sharks, about 79 and 7% of their baseline levels. These species were exploited longer and more intensively than previously thought and responded to fishing and protection with variable and compensatory population trajectories. Our approach highlights the value of integrative and historical analyses to evaluate large marine ecosystems currently considered pristine.
View details for PubMedID 29532033
Tracking the global footprint of fisheries
2018; 359 (6378): 904–7
Although fishing is one of the most widespread activities by which humans harvest natural resources, its global footprint is poorly understood and has never been directly quantified. We processed 22 billion automatic identification system messages and tracked >70,000 industrial fishing vessels from 2012 to 2016, creating a global dynamic footprint of fishing effort with spatial and temporal resolution two to three orders of magnitude higher than for previous data sets. Our data show that industrial fishing occurs in >55% of ocean area and has a spatial extent more than four times that of agriculture. We find that global patterns of fishing have surprisingly low sensitivity to short-term economic and environmental variation and a strong response to cultural and political events such as holidays and closures.
View details for PubMedID 29472481
Sea pens in the Mediterranean Sea: diversity distribution and opportunities for ecosystem recovery
ICES Journal of Marine Science
View details for DOI 10.1093/icesjms/fsy010
Fishery development and exploitation in South East Australia
Frontiers in Marine Science
View details for DOI 10.3389/fmars.2018.00145
- The Resilience of Marine Ecosystems to Climatic Disturbances BIOSCIENCE 2017; 67 (3): 208-220
Local ecological knowledge reveals temporal trends of benthic invertebrates of the Adriatic Sea
Frontiers in Marine Science
View details for DOI 10.3389/fmars.2017.00157
- Species-area relationships as indicators of human impacts on demersal fish communities BRITISH JOURNAL OF POLITICS & INTERNATIONAL RELATIONS 2016; 18 (4): 1186-1198
- Species-area relationships as indicators of human impacts on demersal fish communities DIVERSITY AND DISTRIBUTIONS 2016; 22 (11): 1186-1198
- Falling through the cracks: the fading history of a large iconic predator FISH AND FISHERIES 2016; 17 (3): 875-889
Trends in the exploitation of South Atlantic shark populations
2016; 30 (4): 792-804
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, whereas in the South Atlantic the situation is less clear, although fishing effort has been increasing in this region since the late 1970s. We synthesized information on shark catch rates (based on 871,177 sharks caught on 86,492 longline sets) for the major species caught by multiple fleets in the South Atlantic between 1979 and 2011. We complied records from fishing logbooks of fishing companies, fishers, and onboard observers that were supplied to Brazilian institutions. By using exploratory data analysis and literature sources, we identified 3 phases of exploitation in these data (Supporting Information). From 1979 to 1997 (phase A), 5 fleets (40 vessels) fished mainly for tunas. From 1998 to 2008 (phase B), 20 fleets (100 vessels) fished for tunas, swordfishes, and sharks. From 2008 to 2011 (phase C), 3 fleets (30 vessels) fished for multiple species, but restrictive measures were implemented. We used generalized linear models to standardize catch rates and identify trends in each of these phases. Shark catch rates increased from 1979 to 1997, when fishing effort was low, decreased from 1998 to 2008, when fishing effort increased substantially, and remained stable or increased from 2008 to 2011, when fishing effort was again low. Our results indicate that most shark populations affected by longlines in the South Atlantic are currently depleted, but these populations may recover if fishing effort is reduced accordingly. In this context, it is problematic that comprehensive data collection, monitoring, and management of these fisheries ceased after 2012. Concurrently with the fact that Brazil is newly identified by FAO among the largest (and in fastest expansion) shark sub-products consumer market worldwide.
View details for DOI 10.1111/cobi.12663
View details for Web of Science ID 000379947700013
View details for PubMedID 26634410
- Large marine protected areas (LMPAs) in the Mediterranean Sea: The opportunity of the Adriatic Sea MARINE POLICY 2016; 68: 165-177
- Adriatic Sea: Description of the ecology and identification of the areas that may deserve to be protected RAC/SPA. Tunis. 2016 92 pp.
Species–area relationships as indicators of human impacts on demersal fish communities
Diversity and Distributions
2016; 22 (11): 1186–1198
View details for DOI 10.1111/ddi.12482
- Reconciling predator conservation with public safety FRONTIERS IN ECOLOGY AND THE ENVIRONMENT 2015; 13 (8): 412-417
- Rhinoptera marginata IUCN. 2015 ; The IUCN Red List of Threatened Species
- Squatina squatina IUCN. 2015 ; The IUCN Red List of Threatened Species
- Alopias vulpinus IUCN. 2015 ; The IUCN Red List of Threatened Species
- Sphyrna mokarran IUCN. 2015 ; The IUCN Red List of Threatened Species
- Squatina oculata IUCN. 2015 ; The IUCN Red List of Threatened Species
- Sphyrna lewini IUCN. 2015 ; The IUCN Red List of Threatened Species
- Echinorhinus brucus IUCN. 2015 ; The IUCN Red List of Threatened Species (e.T41801A48909148):
- Carcharhinus plumbeus IUCN. 2015 ; The IUCN Red List of Threatened Species (e.T3853A48946805):
- Neotrygon ningalooensis IUCN. 2015 ; The IUCN Red List of Threatened Species
Falling through the cracks: the fading history of a large iconic predator
FISH AND FISHERIES
View details for DOI 10.1111/faf.12108
- Sharks and other elasmobranchs World Ocean Assessment United Nations. 2015
- Ocean Health Handbook of Ocean Resources and Management Routledge. 2015
- Reconciling predator conservation with public safety FRONTIERS IN ECOLOGY AND THE ENVIRONMENT 2015
- Sphyrna zygaena IUCN. 2015 ; The IUCN Red List of Threatened Species
Predator decline leads to decreased stability in a coastal fish community
2014; 17 (12): 1518-1525
Fisheries exploitation has caused widespread declines in marine predators. Theory predicts that predator depletion will destabilise lower trophic levels, making natural communities more vulnerable to environmental perturbations. However, empirical evidence has been limited. Using a community matrix model, we empirically assessed trends in the stability of a multispecies coastal fish community over the course of predator depletion. Three indices of community stability (resistance, resilience and reactivity) revealed significantly decreasing stability concurrent with declining predator abundance. The trophically downgraded community exhibited weaker top-down control, leading to predator-release processes in lower trophic levels and increased susceptibility to perturbation. At the community level, our results suggest that high predator abundance acts as a stabilising force to the naturally stochastic and highly autocorrelated dynamics in low trophic species. These findings have important implications for the conservation and management of predators in marine ecosystems and provide empirical support for the theory of predatory control.
View details for DOI 10.1111/ele.12354
View details for Web of Science ID 000345216200004
View details for PubMedID 25224645
- Using Disparate Datasets to Reconstruct Historical Baselines of Animal Populations Marine Historical Ecology in Conservation University of California Press. 2014
- Geographical distribution and status. 7.2.1 Mediterranean Sea Sawfish: A Global Strategy for Conservation IUCN. 2014
Cumulative Human Impacts on Mediterranean and Black Sea Marine Ecosystems: Assessing Current Pressures and Opportunities
2013; 8 (12)
Management of marine ecosystems requires spatial information on current impacts. In several marine regions, including the Mediterranean and Black Sea, legal mandates and agreements to implement ecosystem-based management and spatial plans provide new opportunities to balance uses and protection of marine ecosystems. Analyses of the intensity and distribution of cumulative impacts of human activities directly connected to the ecological goals of these policy efforts are critically needed. Quantification and mapping of the cumulative impact of 22 drivers to 17 marine ecosystems reveals that 20% of the entire basin and 60-99% of the territorial waters of EU member states are heavily impacted, with high human impact occurring in all ecoregions and territorial waters. Less than 1% of these regions are relatively unaffected. This high impact results from multiple drivers, rather than one individual use or stressor, with climatic drivers (increasing temperature and UV, and acidification), demersal fishing, ship traffic, and, in coastal areas, pollution from land accounting for a majority of cumulative impacts. These results show that coordinated management of key areas and activities could significantly improve the condition of these marine ecosystems.
View details for DOI 10.1371/journal.pone.0079889
View details for Web of Science ID 000327949300012
View details for PubMedID 24324585
View details for PubMedCentralID PMC3850916
- Long-term change in a meso-predator community in response to prolonged and heterogeneous human impact SCIENTIFIC REPORTS 2013; 3
Long-term change in a meso-predator community in response to prolonged and heterogeneous human impact.
2013; 3: 1057-?
Sharks and rays' abundance can decline considerably with fishing. Community changes, however, are more complex because of species interactions, and variable vulnerability and exposure to fishing. We evaluated long-term changes in the elasmobranch community of the Adriatic Sea, a heavily exploited Mediterranean basin where top-predators have been strongly depleted historically, and fishing developed unevenly between the western and eastern side. Combining and standardizing catch data from five trawl surveys from 1948-2005, we estimated abundance trends and explained community changes using life histories, fish-market and effort data, and historical information. We identified a highly depleted elasmobranch community. Since 1948, catch rates have declined by >94% and 11 species ceased to be detected. The exploitation history and spatial gradients in fishing pressure explained most patterns in abundance and diversity, including the absence of strong compensatory increases. Ecological corridors and large-scale protected areas emerged as potential management options for elasmobranch conservation.
View details for DOI 10.1038/srep01057
View details for PubMedID 23308344
View details for PubMedCentralID PMC3541648
- From archives to conservation: why historical data are needed to set baselines for marine animals and ecosystems CONSERVATION LETTERS 2012; 5 (5): 349-359
The Structure of Mediterranean Rocky Reef Ecosystems across Environmental and Human Gradients, and Conservation Implications
2012; 7 (2)
Historical exploitation of the Mediterranean Sea and the absence of rigorous baselines makes it difficult to evaluate the current health of the marine ecosystems and the efficacy of conservation actions at the ecosystem level. Here we establish the first current baseline and gradient of ecosystem structure of nearshore rocky reefs at the Mediterranean scale. We conducted underwater surveys in 14 marine protected areas and 18 open access sites across the Mediterranean, and across a 31-fold range of fish biomass (from 3.8 to 118 g m(-2)). Our data showed remarkable variation in the structure of rocky reef ecosystems. Multivariate analysis showed three alternative community states: (1) large fish biomass and reefs dominated by non-canopy algae, (2) lower fish biomass but abundant native algal canopies and suspension feeders, and (3) low fish biomass and extensive barrens, with areas covered by turf algae. Our results suggest that the healthiest shallow rocky reef ecosystems in the Mediterranean have both large fish and algal biomass. Protection level and primary production were the only variables significantly correlated to community biomass structure. Fish biomass was significantly larger in well-enforced no-take marine reserves, but there were no significant differences between multi-use marine protected areas (which allow some fishing) and open access areas at the regional scale. The gradients reported here represent a trajectory of degradation that can be used to assess the health of any similar habitat in the Mediterranean, and to evaluate the efficacy of marine protected areas.
View details for DOI 10.1371/journal.pone.0032742
View details for Web of Science ID 000303003500099
View details for PubMedID 22393445
View details for PubMedCentralID PMC3290621
- Correlates of Vertebrate Extinction Risk in Canada BIOSCIENCE 2011; 61 (7): 538-549
Patterns and ecosystem consequences of shark declines in the ocean
2010; 13 (8): 1055-1071
Whereas many land predators disappeared before their ecological roles were studied, the decline of marine apex predators is still unfolding. Large sharks in particular have experienced rapid declines over the last decades. In this study, we review the documented changes in exploited elasmobranch communities in coastal, demersal, and pelagic habitats, and synthesize the effects of sharks on their prey and wider communities. We show that the high natural diversity and abundance of sharks is vulnerable to even light fishing pressure. The decline of large predatory sharks reduces natural mortality in a range of prey, contributing to changes in abundance, distribution, and behaviour of small elasmobranchs, marine mammals, and sea turtles that have few other predators. Through direct predation and behavioural modifications, top-down effects of sharks have led to cascading changes in some coastal ecosystems. In demersal and pelagic communities, there is increasing evidence of mesopredator release, but cascading effects are more hypothetical. Here, fishing pressure on mesopredators may mask or even reverse some ecosystem effects. In conclusion, large sharks can exert strong top-down forces with the potential to shape marine communities over large spatial and temporal scales. Yet more empirical evidence is needed to test the generality of these effects throughout the ocean.
View details for DOI 10.1111/j.1461-0248.2010.01489.x
View details for Web of Science ID 000279934400012
View details for PubMedID 20528897
- Assessment of the Mediterranean swordfish based on the Italian harpoon fishery data. ICES CM 2009; K:16: 1-14
Loss of large predatory sharks from the Mediterranean Sea
2008; 22 (4): 952-964
Evidence for severe declines in large predatory fishes is increasing around the world. Because of its long history of intense fishing, the Mediterranean Sea offers a unique perspective on fish population declines over historical timescales. We used a diverse set of records dating back to the early 19th and mid 20th century to reconstruct long-term population trends of large predatory sharks in the northwestern Mediterranean Sea. We compiled 9 time series of abundance indices from commercial and recreational fishery landings, scientific surveys, and sighting records. Generalized linear models were used to extract instantaneous rates of change from each data set, and a meta-analysis was conducted to compare population trends. Only 5 of the 20 species we considered had sufficient records for analysis. Hammerhead (Sphyrna spp.), blue (Prionace glauca), mackerel (Isurus oxyrinchus and Lamna nasus), and thresher sharks (Alopias vulpinus) declined between 96 and 99.99% relative to their former abundance. According to World Conservation Union (IUCN) criteria, these species would be considered critically endangered. So far, the lack of quantitative population assessments has impeded shark conservation in the Mediterranean Sea. Our study fills this critical information gap, suggesting that current levels of exploitation put large sharks at risk of extinction in the Mediterranean Sea. Possible ecosystem effects of these losses involve a disruption of top-down control and a release of midlevel consumers.
View details for DOI 10.1111/j.1523-1739.2008.00938.x
View details for Web of Science ID 000258216600021
View details for PubMedID 18544092
- By-Catch of sharks in the Mediterranean Sea: available mitigation tools Proceedings of the Workshop on the Mediterranean Cartilaginous Fish with emphasis on Southern and Eastern Mediterranean Turkish marine research foundation; UNEP-MAP; RAC/SPA. 2006
- Long Term Dynamics of the Chondrichthyan Fish Community in the Upper Tyrrhenian Sea ICES CM 2005; N:25: 1-25