Pedro Afonso

Pedro Afonso
IMAR Institute of Marine Research / OKEANOS · Dpt Oceanography and Fisheries - University of the Azores

PhD

About

159
Publications
57,382
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
3,055
Citations
Additional affiliations
January 2017 - December 2021
IMAR Institute of Marine Research / MARE Marine and Environmental Research Centre
Position
  • Researcher
August 2007 - present
IMAR Marine and Environmental Research Centre
Position
  • Invited Scientist

Publications

Publications (159)
Article
Full-text available
Blue shark (Prionace glauca) is amongst the most abundant shark species in international trade, however this highly migratory species has little effective management and the need for spatio-temporal strategies increases, possibly involving the most vulnerable stage or sex classes. We combined 265,595 blue shark observations (capture or satellite ta...
Article
The Azores (mid-north Atlantic) has a long history of artisanal multispecific fishery exploiting marine resources around the islands slopes and seamounts. Due to the archipelago´s oceanic character, demersal-deep-sea and pelagic-offshore species are central to local economy. However, a coastal subsistence fishery is also economically and culturally...
Article
Many large marine predators make excursions from surface waters to the deep ocean below 200 m. Moreover, the ability to access meso- and bathypelagic habitats has evolved independently across marine mammals, reptiles, birds, teleost fishes, and elasmobranchs. Theoretical and empirical evidence suggests a number of plausible functional hypotheses fo...
Article
Formulae for sediment thresholds of motion are commonly based on flume experiments on rounded quartz particles and it is unclear how well they predict thresholds in natural settings. Here, sediment threshold shear stresses were calculated from one such formula using surface grain-size data from 112 sites around Santa Maria Island. To compare with t...
Presentation
Seamounts are biodiversity hotspots for pelagic and oceanic species like the sickle fin devil ray, Mobula tarapacana. As such, this endangered species (IUCN) aggregates every summer at Princess Alice Seamount and Ambrosio Seamount in the Azores archipelago . The aim of our research was to investigate the aggregation at Princess Alice using a non-in...
Article
Full-text available
Acoustic telemetry is widely used to investigate aquatic animal movement. Pulse position modulation (PPM) is an acoustic telemetry method that allows multiple unique identification codes to be transmitted at a single acoustic frequency, typically in the 69 kHz range. However, because the potential number of unique identification codes (i.e. tags) i...
Article
Full-text available
106,107 ✉ replying to A. V. Harry & J. M. Braccini Nature https://doi.org/10.1038/s41586-021-03463-w (2021) Our global analysis 1 estimated the overlap and fishing exposure risk (FEI) using the space use of satellite-tracked sharks and longline fishing effort monitored by the automatic identification system (AIS). In the accompanying Comment, Harry...
Article
This article is a response to Murua et al.'s Matters Arising article in Nature, "Shark mortality cannot be assessed by fishery overlap alone," which arose from arising from N. Queiroz et al. Nature https://doi.org/10.1038/s41586-019-1444-4 (2019).
Article
Aggressive behaviour in fishes, particularly in territorial species, is a common trait used to defend resources such as food or mates. Territorial males of the Mediterranean parrotfish Sparisoma cretense have been described to chase away conspecifics yet other aggressive behaviour repertoire has not been reported for this species. We describe, for...
Article
Full-text available
The macroalgal flora of the Island of São Miguel (eastern group of the Azores Archipelago) has attracted the interest of many researchers in the past, the first publications going back to the nineteenth century. Initial studies were mainly taxonomic, resulting in the publication of a checklist of the Azorean benthic marine algae. Later, the establi...
Article
Full-text available
Background: The algal flora of the Island of Santa Maria (eastern group of the Azores archipelago) has attracted interest of researchers on past occasions (Drouët 1866, Agardh 1870, Trelease 1897, Schmidt 1931, Ardré et al. 1974, Fralick and Hehre 1990, Neto et al. 1991, Morton and Britton 2000, Amen et al. 2005, Wallenstein and Neto 2006, Tittley...
Article
Kelp was first recorded for the remote warm‐temperate Azores archipelago (central North Atlantic) as late as 1971, when a few Laminaria specimens were collected on the Formigas Bank at depths beyond conventional SCUBA diving reach. A shortage of technical means and projects targeting mesophotic environments has since kept this offshore marine prote...
Article
Full-text available
The algal flora of the western group of the Azores archipelago (Islands of Flores and Corvo) has attracted the interest of many researchers on numerous past occasions (such as Drouet 1866, Trelease 1897, Gain 1914, Schmidt 1929, Schmidt 1931, Azevedo et al. 1990, Fralick and Hehre 1990, Neto and Azevedo 1990, Neto and Baldwin 1990, Neto 1996, Neto...
Article
Full-text available
Climate-driven expansions of ocean hypoxic zones are predicted to concentrate pelagic fish in oxygenated surface layers, but how expanding hypoxia and fisheries will interact to affect threatened pelagic sharks remains unknown. Here, analysis of satellite-tracked blue sharks and environmental modelling in the eastern tropical Atlantic oxygen minimu...
Article
Full-text available
The macroalgal flora of Graciosa (central group of Azores archipelago) is poorly known, with only 116 species recorded so far (authors personal data). The published information reflects occasional collections from sporadic field visits to the Island. To overcome this, a thorough investigation under the Expedition “GRACIOSA/2004”, the Campaigns “PAD...
Article
Full-text available
Lying between continental Europe and North America, the Azores is the most isolated archipelago in the North Atlantic Ocean. Its one million square km Exclusive Economic Zone (EEZ) comprises mostly deep seafloor interspersed with shallower portions offered by the Mid-Atlantic Ridge, over 100 seamounts, and the slopes of the nine islands. After the...
Article
The spatial dynamics of marine populations are shaped by habitat availability, environmental variability and individual interactions, particularly when multiple species share limited habitat such as patchy offshore reefs. The yellowmouth barracuda Sphyraena viridensis and the almaco jack Seriola rivoliana are the 2 most abundant bentho-pelagic reef...
Book
Full-text available
Pouca gente saberá que no mar profundo da região habitam 25 espécies diferentes de tubarões de profundidade. Várias destas espécies são capturadas de forma acidental nas pescarias locais com palangres de profundidade. Por esta razão, profissionais do IMAR/ Centro Okeanos da Universidade dos Açores, em colaboração com o Observatório do Mar dos Açore...
Article
Fisherman have known and explored the association between tuna and whale sharks for centuries. Just as in the past, present day industrial fishers search for the presence of whale shark as cue to locate tuna schools. These whale shark-tuna associations have been usually assumed to result from the same ecological drivers that govern the attraction o...
Article
Devil rays are considered pelagic filter-feeders but direct observation of their foraging in the wild is very scarce and their feeding ecology is known essentially from indirect methods. On September 2018, a group of 16 sicklefin devil rays were observed preying on bait balls of longspine snipefish (Macroramphosus scolopax), together with their ass...
Article
Full-text available
Many marine animals produce sounds in several phases of their life cycles, either actively or as a byproduct of their activities, such as during mate attraction or when moving. Recent studies of underwater soundscapes have proved passive acoustic monitoring to be a cost-effective, non-invasive tool to understand ecological processes, especially whe...
Article
Full-text available
Among threats to marine species, overfishing has often been highlighted as a major contributor to population declines and yet fishing effort has increased globally over the past decade. This paper discusses the decadal reassessment of groupers (family Epinephelidae), an important and valuable group of marine fishes subjected to high market demand a...
Article
Full-text available
Marine ecosystem-based management requires good spatial information on the distribution of marine species and habitats. Often, such information is limited to a few sampled locations, but modelling techniques can be applied to produce predictive distribution maps. A harmonized broad-scale seabed habitat map was recently produced for the archipelagos...
Article
Full-text available
The increasing public perception that marine megafauna is under threat is an outstanding incentive to investigate their essential habitats (EMH), their responses to human and climate change pressures, and to better understand their largely unexplained behaviors and physiology. Yet, this poses serious challenges such as the elusiveness and remotenes...
Article
Seven scalloped hammerhead sharks (Sphyrna lewini) were satellite tagged around the Saint Peter and Saint Paul Archipelago (SPSPA), located at the equatorial Mid-Atlantic ridge, to investigate their vertical and horizontal movements. All sharks remained in the surroundings of the SPSPA over the course of the 120-day monitoring period, suggesting a...
Article
Full-text available
Broadbill swordfish (Xiphias gladius) is a key species in commercial fisheries, but management efforts continue to be hindered by data gaps in their basic biology, including ongoing debate over stock boundaries and movement between management zones. We deployed 20 pop-up satellite archival transmitting (PSAT) tags on juvenile swordfish in the Azore...
Article
Full-text available
The Azores, Madeira, Selvagens, Canary Islands and Cabo Verde are commonly united under the term "Macaronesia". This study investigates the coherency and validity of Macaronesia as a biogeographic unit using six marine groups with very different dispersal abilities: coastal fishes, echinoderms, gastropod molluscs, brachyuran decapod crustaceans, po...
Article
Full-text available
The Azores, Madeira, Selvagens, Canary Islands and Cabo Verde are commonly united under the term “Macaronesia”. This study investigates the coherency and validity of Macaronesia as a biogeographic unit using six marine groups with very different dispersal abilities: coastal fishes, echinoderms, gastropod molluscs, brachyuran decapod crustaceans, po...
Article
The archipelago of the Azores (mid-north Atlantic Ocean) is an outermost region of the European Union (EU) in which small-scale fisheries are a strong component of the local economy. Bottom longlining and handlining are the most important Azorean fisheries in landing values, fishing vessels and fishers. Despite their high selectivity and low discar...
Article
Full-text available
Squid are mobile, diverse, ecologically important marine organisms whose behavior and habitat use can have substantial impacts on ecosystems and fisheries. However, due in part to the inherent challenges of monitoring squid in their natural marine environment, fine-scale behavioral observations of these free-swimming, soft-bodied animals are rare....
Article
Full-text available
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...
Article
Full-text available
Converting assemblages of marine protected areas (MPAs) into functional MPA networks requires political will, multidisciplinary information, coordinated action and time. We developed a new framework to assist planning environmental representativity in a network across the marine space of Portugal, responding to a political commitment to protect 14%...
Conference Paper
Full-text available
The Azorean Government is currently working on a re-evaluation and expansion of the regional Marine Protected Areas (MPAs), and reviewing the marine conservation legal framework to clarify its powers, uses and regulations. This process, where stakeholder involvement is expected to be inclusive and continuous, will determine the adoption of MPAs man...
Chapter
Full-text available
Under the Landing Obligation (LO) fishers will need to reduce or land fish that were previously discarded. In this chapter we look at how they might be able to do that by summarising a number of studies conducted in various European regions. We start by describing a series of “challenge” trials where fishers tried to reduce their discards by whatev...
Chapter
Full-text available
To address the challenges of the Landing Obligation, fishers need to be able to adjust the selective performance of each fishing operation in response to what they observe on the fishing grounds and to what they bring on board. This will include strategies on where and when to fish but also on how to fish, which we examine here. In particular, we f...
Article
Full-text available
Seven scalloped hammerhead sharks (Sphyrna lewini) were satellite tagged around the Saint Peter and Saint Paul Archipelago (SPSPA), located at the equatorial Mid-Atlantic ridge, to investigate their vertical and horizontal movements. All sharks remained in the surroundings of the SPSPA over the course of the 120-day monitoring period, suggesting a...
Article
Marine reserves across different eco-regions and habitats have proven to benefit exploited fish populations within their borders. There is also mounting evidence, mostly from continental shelf regions, that such positive effects will depend on the species ecological traits (e.g. mobility) and on the characteristics of the reserves (e.g. design, age...
Article
Full-text available
This nearshore, rocky reef species has a restricted range, and occurs only in the four island archipelagos of Macaronesia. It is naturally rare in the northern part of its range, and more common to the south. Declines have occurred in the Azores and the Canary Islands due to overfishing. Heavy targeting of aggregations has resulted in significant d...
Article
In contrast to the vast majority of European maritime territories, the Azores is an isolated oceanic archipelago in the North East Atlantic characterised by small-scale hooks-and-lines fisheries. Yet, in spite of the low environmental impact of such fishing gears, there is no solid integrative information on the discard practices. This study bridge...
Presentation
A wide diversity of elasmobranch occurs in the Azores, a Portuguese archipelago located by the Mid-Atlantic Ridge. Subject to a commercial fishery for their liver oil until the late 90s, declines in species abundance has led the EU to progressively implement and strengthen catch limits of deep-water sharks, until a TAC 0 was set in 2010. Nowadays,...
Article
Full-text available
Background Globally, there are a large and growing number of researchers using biotelemetry as a tool to study aquatic animals. In Europe, this community lacks a formal network structure. The aim of this study is to review the use of acoustic telemetry in Europe and document the contribution of cross-boundary studies and inter-research group collab...
Article
Full-text available
We analyzed three acoustic telemetry datasets of single tagged individuals to argue that, at a time of data deficiency, “solo datasets” have the ability to uncover singular patterns. Here, a greater amberjack (Seriola dumerili), a female school shark (Galeorhinus galeus) and a Salema, (Sarpa salpa) provided relatively long and insightful individual...
Article
Full-text available
Biologging technology has provided scientists with unprecedented tools to investigate the ecology and behaviour of marine animals, but tag deployment and attachment methods have lagged behind. Electronic tagging of elasmobranchs still essentially involves implanting anchors or drilling the fins of restrained animals. Here, we present two new non-in...
Poster
Fisheries discards have been a growing concern in European fisheries, thus a landing obligation for species under quotas was introduced by The Common Fisheries Policy reform. Because very few is still known about the role of discards in marine ecosystems, this work aims at assessing the ecological role of discards in the Azores Exclusive Economic Z...
Article
Full-text available
A vulnerable species group, such as, the elasmobranchs, in a data-deficient context presents a complicated management problem. Evidence suggests that the Azores islands, a remote archipelago on the Mid-Atlantic Ridge, serve essential functions in the life-history of species across taxa. The diversity of marine resources within its EEZ are exploited...
Poster
Full-text available
We present two alternative solutions for short term deployments of external tags and sensors on two species of elasmobranchs
Article
Full-text available
Synchronous reproduction has been reported in many tropical damselfishes, and it appears that temperature is the main driver of synchrony at these latitudes. However, reproductive synchrony and its relation to temperature is less well understood in temperate damselfish. The endemic Azores chromis (Chromis limbata) was chosen as a study species to a...
Presentation
Full-text available
The Azores deep-sea bottom hook-and-line fishing might be strongly impacted by the upcoming European Landing Obligation (LO), although having low discards of about 10% of the catch. In this study, fishers were interviewed to assess their perceptions about the LO, and existing and new discard avoidance practices. The LO is perceived as inappropria...
Article
Full-text available
Europe has a long tradition of exploiting marine fishes and is promoting marine economic activity through its Blue Growth strategy. This increase in anthropogenic pressure, along with climate change, threatens the biodiversity of fishes and food security. Here, we examine the conservation status of 1,020 species of European marine fishes and identi...