Jorge Fontes

AEROS MH-1 is a 3U CubeSat pathfinder toward a future ocean-observing constellation focused on the Portuguese Atlantic region. Launched on March 4, 2024, the spacecraft was deployed into a 500 km sun-synchronous orbit. The spacecraft contains a miniaturized Hyperspectral Imager (HSI), a 5 MP RGB camera, and a software-defined radio (SDR) for interfacing with Argos and LoRa signals from remote platforms. These payloads support Portuguese scientific innovation and foster international space industry partnerships, with data processed for end-users through a web-based Data Analysis Center. The HSI collects ocean color data to investigate oceanographic characteristics such as primary productivity, chlorophyll-a concentrations, and water quality—key factors that influence the spatiotemporal distribution of marine organisms. The SDR facilitates ocean-to-space connectivity, receiving signals from tagged marine organisms, vessels, subsurface floats, and buoys that utilize Argos and/or LoRa frequencies. Correlation of location data from animal-borne platforms with oceanographic observations enhances marine spatial planning, fisheries management, ecosystem-based management, and bio-oceanographic research. This paper discusses payload design, performance validation for use cases, and compliance with community-defined measurement requirements. Since launch, AEROS MH-1 has downlinked over 40 RGB images of global scenes and remains operational. However, an observed power anomaly has delayed further payload demonstrations; troubleshooting efforts are ongoing.

Entanglement in marine debris is a widespread threat affecting animals worldwide. However, most incidents remain underreported due to the challenges of systematically monitoring their occurrence. This study investigates the entanglement of marine vertebrates in plastic based on 17 yr (2008-2024) of opportunistic observations between the Azores Archipelago and mainland Portugal. The data was obtained from (1) sea users (tourist operators, scientists, fishery observers) and (2) a stranding network. Only events supported by clear visual evidence were included in the analysis. We report a total of 41 entanglements in either abandoned, lost, or otherwise discarded fishing gear (ALDFG; 56%) or in single-use plastics (SUPs; 44%) in 10 different vertebrate species (blue shark, swordfish, loggerhead and green sea turtles, Cory’s shearwater, bottlenose dolphin, minke, Bryde, and sei whales, and Sowerby’s beaked whale). Most individuals (78%) presented visible impacts from the entangling debris, typically external lesions (91%) or mortality (9%). Specific injuries in live animals included constrictions (46%), skin damage such as wounds or lacerations (39%), limb loss (11%), and body deformations (4%). Although opportunistic data may not fully capture the extent and severity of entanglements, we found that floating plastic exerts additional pressure on open ocean ecosystems. This is often overlooked due to a limited network of stakeholders supporting data sharing, which is crucial for understanding this ongoing threat. Overall, this study offers the first baseline evidence on plastic litter entanglements among several marine vertebrate species in the open NE Atlantic, supporting consistent monitoring for the EU Marine Strategy Framework Directive.

Animal movements and the associated energy costs dictate an individual’s scope for activity and habitat use. Yet in situ measurements of movement often fail to quantify whole-body movement and their physiological costs. These challenges lead to data gaps connecting how movement behaviours and energy output interact to constrain species’ biogeography. Here we combined swim tunnel respirometry and multi-positional field biologging data to estimate the energy output of squid ( Loligo forbesii ), an ecologically key marine invertebrate. Laboratory respirometry experiments revealed a strong correlation between body mass and metabolic rate during fin-contributed swimming, enabling energy cost estimates in the wild. Free-ranging squid enacted dynamic and diverse fin and jet swimming that varied on short time scales. Animals largely selected (66%) low-amplitude fin-contributed movements where fin waves propagated metachronally. Higher amplitude fin and jet movements were rare, accounting for 4% of time budgets. Application of the bioenergetic model on naturally exhibited behaviours estimated that animals consumed 3117 ± 532 mg O ₂ per day to fuel the predominant metachronal fin movements, an expenditure energetically comparable to that of similar-niche fishes. These unique data reveal substantial behavioural flexibility and indicate squid prefer low-cost movement behaviours that may enable squids’ high growth rates and successful competition with fishes.

Global climate‐driven ocean warming has decreased dissolved oxygen (DO) levels (ocean deoxygenation) leading to expansions of hypoxic zones, which will affect the movements, behaviour, physiology and distributions of marine animals. However, the precise responses of animals to low DO remains poorly understood because movements and activity levels are seldom recorded alongside instantaneous DO in situ. We describe a new animal‐attached (dissolved oxygen measuring, DOME) archival tag with an optical oxygen sensor for recording DO, in addition to sensors for temperature and depth, a triaxial accelerometer for fine‐scale movements and activity, and a GPS for tag recovery. All sensors were integrated on a single electronic board. Calibration tests demonstrated small mean difference between DOME tag and factory‐calibrated DO sensors (mean relative error of 5%). No temporal drift occurred over a test period three times longer than the maximum deployment time. Deployments on four blue sharks (Prionace glauca) in the central North Atlantic Ocean showed regular vertical oscillations from the surface to a maximum of 404 m. Profiles from diving sharks recorded DO concentrations ranging from 217 to 272 μmol L⁻¹, temperatures between 13°C and 23°C, and identified an oxygen maximum at ~45 m depth, all of which were consistent with ship‐based measurements. Interestingly, the percentage of time sharks spent burst swimming was greater in the top 85 m compared to deeper depths, potentially because of higher prey availability in the surface layer. The DOME tag described blue shark fine‐scale movements and activity levels in relation to accurately measured in situ DO and temperature, with the potential to offer new insights of animal performance in low oxygen environments. Development of a tag with physico‐chemical and movement sensors on a single electronic board is a first step towards satellite relay of these data over broader spatiotemporal scales (months over thousands of kilometres) to determine direct and indirect responses of marine animals to heatwave and deoxygenation events.

We investigated, for the first time, the hitchhiker‐host fidelity of deep‐diving whale sharks and Chilean devil rays. We found that two of the most ubiquitous oceanic hitchhikers, the common remora and the pilot fish, are able to follow their hosts to bathypelagic depths, where they are exposed to extreme gradients of light, dissolved oxygen, temperature, and pressure. We documented a deep dive of a large whale shark hosting remoras and pilot fish. Common remora was observed at the deepest section of the dive, at 1460 m, where the water temperature was 3.6°C. A pilot fish was recorded at 900 m, during the ascent phase, with the water temperature of 7.5°C. Although the adaptations that allow these hitchhikers to mitigate the impacts of such extreme environmental conditions remain unknown, we discuss these findings in the framework of the ecophysiology of deep diving and the hitchhiker‐host fidelity.

As regional endotherms, lamnid sharks can sustain high cruising speeds and perform frequent speed bursts. However, since endothermy comes with high energetic costs, lamnids may adopt different swimming strategies to manage their energy budget. Understanding such strategies is essential to provide behavioural and physiological context to their broader movement ecology. The endangered shortfin mako ( Isurus oxyrinchus ) possibly has the highest energy requirements among lamnids, but our understanding of its swimming behaviour is still limited. We equipped three shortfin mako sharks with high-resolution multi-sensor tags to measure their swimming kinematics in the wild. While swimming horizontally, individuals favoured tail-beat frequencies around 0.6 Hz at speeds comparable to those of ectothermic sharks ( ca 0.5 m s ⁻¹ ). All individuals displayed yo-yo-like diving patterns where, for a given tail-beat frequency, speeds were higher during descents, as expected for a negatively buoyant fish. Contrary to what was expected, gliding was almost absent (less than 1.31%). Speed bursts reaching up to 3.6 m s ⁻¹ were observed during the day but ceased shortly after dusk, implying a diel change in swimming behaviour. As large-scale research efforts are hindered by this species' increasing rarity, opportunistic high-resolution datasets, like the present, are fundamental to improve our understanding of shortfin mako's behaviour and ecology.