Forty species of shore and shallow water brachyuran crabs are reported from the remote oceanic Archipelago Trindade and Martin Vaz (TMV), 11 of which were previously known from Trindade Island, 28 are recorded from the Archipelago for the first time, and one is a new species, Epialtus parvulus sp. nov. This brings the total known shore and shallow water decapod fauna of TMV to 99 species. The opportunity is taken here to elaborate on the taxonomy of the species reported from TMV. One new genus, Mecataleptodius, is recognized for two species, Cancer parvulus Fabricius, 1793, its type species, and Cataleptodius olsoni Manning Chace, 1990, endemic to Ascension Island. The following seven nominal species are synonymized: Acanthonyx dissimulatus Coelho in Coelho Torres, 1993; A. scutiformis (Dana, 1851a); Dromia gouveai Melo Campos Junior, 1999; Epialtus portoricensis Rathbun, 1923; Ranilia guinotae Melo Campos Junior, 1994; R. saldanhai H. Rodrigues da Costa, 1970; and Omalacantha garthi (Lemos de Castro, 1953). TMV is a subset of the western Atlantic crab fauna (23 species or 57.5%), also including 8 (20%) amphi-Atlantic species, 3 (7.5%) amphi-American, 3 (7.5%) endemic, 2 (5%) cosmopolitan, 1 (2.5%) known from both sides of the Atlantic and the Indo-West Pacific. The crab fauna of TMV, Ascension (AS) and Saint Helena (SH) are compared with one another as well as with that of the oceanic islands Fernando de Noronha (FN) and the Rocas Atoll (RA) by means of nonmetric multidimensional scaling (NMDS) applied to a dissimilarity matrix generated by Jaccards coefficient. TMV-FN-RA and AS-SH clustered into two distinct groups according to the composition of their crab fauna. The NMDS analysis ranked the species that cause segregation of the crab faunal assemblages among TMV, AS, and SH, while revealing a gradient in species composition between the two groups of islands (TMV-FN-RA and AS-SH) formed by the amphi-Atlantic species. Island isolation, age and size alone do not explain the existing differences in species richness among TMV, AS and SH. The taxonomic composition of the shallow water fauna in these islands is likely to have been determined by several variables that were interwoven differently along their evolutionary history.

Plants endemic to oceanic archipelagos are suitable for studying evolution, being isolated on substrates of different ages. Evolution has been recent, rendering traditionally employed sequences insufficiently variable for resolving relationships. This study includes sampling in the genus Tolpis (Asteraceae) from the Azores, Madeira, and Cape Verde, and expands upon an earlier study demonstrating the efficacy of multiplexed shotgun genotyping (MSG) for resolving relationships in Canarian Tolpis. Genomic libraries for 90 accessions of Tolpis and two from the outgroup were generated for genotyping individuals using MSG. Loci were de novo assembled with iPyrad, which clusters MSG loci within and between samples. A maximum likelihood phylogeny was generated with RAxML. Ancestral area reconstruction was inferred using R package BioGeoBEARS. MSG data recovered a highly resolved phylogeny from population to inter-archipelago levels. Ancestral area reconstruction provided biogeographic hypotheses for the radiation of Macaronesian Tolpis. Four major clades were resolved. The Madeiran endemic T. macrorhiza is sister to other Tolpis. Species from the Canaries, Cape Verdes, and the continent are sister to T. succulenta from Madeira, which has a sister subclade of Azorean populations composed of T. succulenta and T. azorica. Population-level resolution suggests unrecognized taxa on several archipelagos. Ancestral reconstruction suggests initial dispersal from the continent to Madeira, with dispersal to the Azores, then dispersal from Madeira to the Canary Islands, with both subsequent dispersal to the Cape Verdes and back-dispersal to the continent. Single-island radiations and inter-island dispersal are implicated in divergence in Macaronesian Tolpis.

Abstract We report the rediscovery of Lecocarpus leptolobus at its type locality, and restrict the latter to El Ripioso, San Cristóbal, Galapagos. We compare the morphology of the population at this site with other populations of Lecocarpus on San Cristóbal and other Galapagos islands. We conclude that L. leptolobus is a valid taxon endemic to the south-western half of San Cristóbal and is not synonymous with L. lecocarpoides, whereas populations further north-east on the same island constitute a separate species validly named L. darwinii. These two taxa support the idea of a former biogeographic barrier between the two halves of San Cristóbal. Plants at two of the easternmost localities of the south-western species show some characters intermediate between the two species, possibly representing introgression following easing of the barrier. The three specimens of Lecocarpus collected on San Cristóbal by Charles Darwin, all mounted on a single herbarium sheet, comprise one branch of L. leptolobus and two of L. darwinii. We identify possible sites for Darwin’s collections based on information about his explorations. We find grounds for accepting the taxon Acanthospermum brachyceratum as a subspecies of L. lecocarpoides endemic to Gardner-by-Española, Osborn and Xarifa islets, the first of these being the type locality, demonstrating that even narrow sea barriers can contribute to plant radiation in oceanic archipelagos. On the basis of our findings, we provide a new key to the taxa of Lecocarpus.

Canary Islands is a North Atlantic Ocean archipelago in the Macaronesian region that stand out for its great algae diversity and its climatic conditions. However, even in this low industrialised area, human activities tend to increase the marine pollution. Asparagopsis spp. and Liagora spp. algae are red algae frequent in the Canary Islands’ coasts. Therefore, they could be used as bio-indicators of marine pollution for trace elements. A total of 30 samples of both algae’s species from Tenerife’s southern coast, specifically in Playa Grande, Porís de Abona, in Arico (Tenerife, Spain) were used to determine trace element content (Mn, B, Ba, Cu, Cd, Co, Fe, Li, Mo, Ni, Pb, Sr, V, Zn, Al, Cr) through inductively coupled plasma atomic emission spectroscopy (ICP—OES). Highest Fe concentrations were found in Liagora spp. concentrations (1190 ± 1545 mg/kg dw) and Al (288 ± 157 mg/kg dw) was more significant in Asparagopsis spp. High concentrations of B were also registered in both species 80.2 ± 34.2 mg/kg dw and 77.9 ± 34.2 mg/kg dw, respectively. The recorded concentrations show a high contamination scenario in the collected area. Porís is known by its marine diversity and by its higher pollution levels, compared with other locations of Tenerife, due to the currents present on the Canary Island and its singular north orientation, actions must be taken to reduce pollution.

ABSTRACT Late Quaternary deposits containing fossil snail shells were sampled from nine sites on Deserta Grande and three on Bugio, two of the three Desertas Islands in the oceanic Madeiran archipelago. In total, 3,432 shells representing 45 species or subspecies were retrieved. Calibrated amino acid racemization yielded ages ranging from >45 to 6 ka, with variation by site often confounded by reworking of mostly colluvial deposits. The assemblages found are compared with the extant fauna, itself a subject of intensive recent study. Of the 45 taxa, 18 are apparently extinct, and a further 5 no longer survive on the Desertas. A similar pattern emerges when each island is considered separately. The level of local extinction (c. 50%) is greater than seen on the larger, nearby islands of Madeira and Porto Santo. There are few endemic species in the extant fauna not represented in the fossil assemblages, but there are a number of possibly adventitious species, some with wide distributions in Europe. There is little evidence of faunal change within the limits of the age range available, and extinction seems to be concentrated in the later Holocene. It is attributed to the massive habitat destruction that occurred subsequent to human occupation from the 15th century CE onwards. The study emphasizes the depauperate nature of many extant island faunas subject to human disturbance.

Geographic isolation, a relatively low species richness and high endemism make oceanic islands excellent natural laboratories for ecological and evolutionary studies. Here we used Baited Remote Underwater stereo-Video systems (stereo-BRUVS) to investigate the taxonomic, trophic and size structures of fish assemblages from pelagic and mesophotic reef ecosystems in the smallest archipelago of the equatorial Atlantic Ocean, the Saint Peter and Saint Paul’s Archipelago (SPSPA). The occurrence of steep reef walls favors studies on the ecological connections between pelagic and reef ecosystems. We performed five pelagic stereo-BRUVS deployments and fourteen benthic stereo-BRUVS deployments, totaling 1440 min of footage. We recorded 14 species from eight families in the pelagic ecosystem, with Carangidae and Balistidae as the most diverse families. The most abundant species were Elagatis bipinnulata (Quoy and Gaimard, 1825), Melichthys niger (Bloch, 1786), and Caranx crysos (Mitchill, 1815), which together accounted for over 75% of the total relative abundance. The carnivores were the most diverse and abundant trophic group. On the mesophotic reefs, 41 taxa were recorded, with carnivores and planktivores being the most diverse, whereas omnivores were the most abundant. Here, the most abundant species were M. niger, Azurina multileneata, Chromis vanbebberae, Seriola rivoliana, Caranx lugubris and Stegastes sanctipauli. Nine species were recorded in both ecosystems, with Melichthys niger, Caranx lugubris and S. rivoliana being the main species linking them (i.e., occurring in both). These species are known to forage in both pelagic and mesophotic reef ecosystems, and thus represent potential ecological links between them. Such links combined with the endangered status of some species, suggest the need for an integrated management strategy in this remote archipelago.

Marine megafauna serve valuable ecological and economical roles globally, yet, many species have experienced precipitous population declines. The significance of marine megafauna is particularly evident in Macaronesia, a complex of oceanic archipelagos in the Northeast Atlantic Ocean. Macaronesian islands provide important habitats for marine megafauna species, in turn supporting considerable regional economic activity (e.g., ecotourism and fisheries). Despite this, concerted efforts to manage marine megafauna throughout Macaronesia have been limited. This systematic review provides the first description of the trends in marine megafauna research in this unique insular ecosystem, to provide a better understanding of taxa-specific research needs and future directions for conservation. We identified and validated 408 peer-reviewed publications until 2021 following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. Literature was dominated by marine mammal research conducted in the northern archipelagos (Azores, Madeira, and Canary Islands) and marine turtle research conducted in Cabo Verde. Much less research focused on large-bodied fish, especially in Madeira and Canary Islands, leaving some of the most vulnerable species regionally data deficient. Research across scientific disciplines focused more on biological studies than management and policy, and anthropogenic impacts were quantified more frequently on mammals or turtles and less on fishes. By identifying gaps in our knowledge of megafauna in relation to threats faced by these organisms, we offer taxa-specific recommendations for future research direction. Although, overall our results indicate that determining population level connectivity should be a major research priority among many marine megafauna species as this information is vital to numerous management strategies, including marine protected areas. In this review, we present a basis of understanding of the current work in Macaronesia, highlighting critical data gaps that are urgently needed to guide the next steps toward establishing conservation priorities for marine megafauna in the region.

Evolutionary processes on islands, and the attributes of rare plant species restricted to islands have received increasing attention in the last decade, but most of the evidence comes from oceanic archipelagos while continental islands have been much less studied. We test if narrow endemic species of Aegean islands (E Mediterranean region) have evolved particular trait values and ecological attributes. In 64 pairs of congeneric species i.e., an island endemic and a congeneric widespread species, we compared morphological traits (both vegetative and reproductive), and altitudinal range using a phylogenetically constrained multilevel model. Island endemics had larger propagules, larger petals, shorter stems, shorter flowering duration, and they occupied a narrower altitudinal range. The results are interpreted in terms of lower competitive ability and lower dispersal capacity in Aegean endemics. Larger corolla could be accounted for by competition for pollinators in insect-rich ecosystems. Field observations are needed to test if island endemics and their widespread congeners occupy distinct niches when in sympatry on the same island.

Abstract AimAfter colonising isolated islands, many types of plants and animals undergo extreme morphological diversification. In stark contrast, other island taxa change more subtly and converge evolutionarily on intermediate body size (the island rule). This paradox of island evolution has gone undetected for decades, perhaps because each pattern has been investigated separately using different analytical tools. Here, I investigate the paradox of island evolution in the endemic floras of four oceanic archipelagos in the Southwest Pacific.LocationChatham, Kermadec, Lord Howe & Norfolk Islands.TaxonWoody plants.MethodsI test whether the sizes of ‘solitary endemics’ (species that evolved anagenetically in the absence of co‐occurring endemic congeners) are correlated with their closest mainland ancestors. I also test whether island–mainland size relationships in 'solitary endemics' differ from isometry, as predicted by the island rule. Next, I test whether the stature of ‘co‐occurring endemics’ (closely related, often cladogenetic species) exhibits exaggerated differentiation.ResultsThe stature of 'solitary endemics' was correlated with their mainland relatives, and two out of the four archipelagos showed evidence of the island rule. On the other hand, the stature of 'co‐occurring endemics' was unrelated to their closest mainland relatives and often highly differentiated.Main conclusionsOverall results suggest that the island paradox arises from two distinct evolutionary pathways. Solitary endemics evolve more slowly and often converge on intermediate morphology, while co‐occurring endemics evolve more rapidly and often exhibit highly differentiated morphology. Future work aimed at a better understanding of the mechanisms underpinning the island paradox could help to further unite phylogenetic work on adaptive radiations and macroecological tests of the island rule under a single conceptual umbrella.

Litter ingestion and entanglement in green turtles: An analysis of two decades of stranding events in the NE Atlantic

Mapping Marine Ecosystem Services Potential Across an Oceanic Archipelago: Applicability and Limitations for Decision-Making

Tropical waters show different regional aspects due to specificities in their nutrient biogeochemical cycles, which can affect the carbon system and influence their regional role as sinks or sources of CO2. This study was performed on particular tropical areas that present a different seasonal behaviour related to the carbon cycle observed in the late rainy season (July 2013). Understanding the CO2 drawdown and outgassing potential in these areas is needed to call attention to more long-term monitoring efforts and protect understudied tropical coastal systems more efficiently. This study is focused on nutrient values, hydrological data, biogeochemical carbon behaviour linked to the carbonate system and includes estimates of CO2 fluxes in three contrasting areas off the northeastern Brazilian shelf: 1) an urbanised estuary (Recife-REC), 2) a coastal Island (Itamaracá-ITA) and 3) an oceanic archipelago (Fernando de Noronha-FN). In general, REC acted as a source, while ITA and FN as carbon sinks. In ITA, despite the high DIC and Total Alkalinity observed (mean ~2360 μmol·kg-1), the sink is associated with an effective cascading of atmospheric CO2 associated with turbulent shallow waters coupled with biogenic removal of and precipitation of CaCO3 by coralline algae. FN acted as a sink, linked to minor decreases in Total Alkalinity (mean~2295 μmol·kg-1) influenced by ammonium-based primary production, nitrogen fixation and sporadic entrainment of nutrient rich waters in the upper thermocline. More studies in different western tropical Atlantic coastal systems can improve the knowledge of tropical shelf seas and their contribution to the ocean carbon budget under specific regional trophic regimes.

Batoids, distributed from shallow to abyssal depths, are considerably vulnerable to anthropogenic threats. Data deficiencies on the distribution patterns of batoids, however, challenge their effective management and conservation. In this study, we took advantage of the particular geological and geomorphological configuration of the Canary Islands, across an east‐to‐west gradient in the eastern Atlantic Ocean, to assess whether patterns in the occurrence and abundance of batoids varied between groups of islands (western, central, and eastern). Data were collected from shallow (<40 m, via underwater visual counts and by a local community science program) and deep waters (60–700 m, via ROV deployments). Eleven species of batoids, assessed by the IUCN Red List of Threatened Species, were registered, including three “Critically Endangered” (Aetomylaeus bovinus, Dipturus batis, and Myliobatis aquila), three “Endangered” (Gymnura altavela, Mobula mobular, and Rostroraja alba), two “Vulnerable” (Dasyatis pastinaca and Raja maderenseis), and two “Data Deficient” (Taeniurops grabata and Torpedo marmorata). Also, a “Least Concern” species (Bathytoshia lata) was observed. Overall, batoids were ~1 to 2 orders of magnitude more abundant in the central and eastern islands, relative to the western islands. This pattern was consistent among the three sources of data and for both shallow and deep waters. This study, therefore, shows differences in the abundance of batoids across an oceanic archipelago, likely related to varying insular shelf area, availability of habitats, and proximity to the nearby continental (African) mass. Large variation in population abundances among islands suggests that “whole” archipelago management strategies are unlikely to provide adequate conservation. Instead, management plans should be adjusted individually per island and complemented with focused research to fill data gaps on the spatial use and movements of these iconic species.

Human impacts reshape ecological communities through the extinction and introduction of species. The combined impact of these factors depends on whether non-native species fill the functional roles of extinct species, thus buffering the loss of functional diversity. This question has been difficult to address, because comprehensive information about past extinctions and their traits is generally lacking. We combine detailed information about extinct, extant, and established alien birds to quantify historical changes in functional diversity across nine oceanic archipelagos. We found that alien species often equal or exceed the number of anthropogenic extinctions yet apparently perform a narrower set of functional roles as current island assemblages have undergone a substantial and ubiquitous net loss in functional diversity and increased functional similarity among assemblages. Our results reveal that the introduction of alien species has not prevented anthropogenic extinctions from reducing and homogenizing the functional diversity of native bird assemblages on oceanic archipelagos.

Reefs are the richest marine ecosystems. Their benthic communities generate structural complexity and participate in nutrient cycles, providing habitat and food for many marine species. These ecosystems have been threatened by local and global anthropogenic impacts and changes in community structure have led to loss of biodiversity, ecosystem function and services worldwide. Most studies about these structural changes have been conducted in Caribbean and Indo-Pacific coral reefs. In the Southwestern Atlantic, where reefs are naturally algae-dominated, these efforts are incipient, especially at oceanic islands where local anthropic impacts tend to be lower, and natural and climate-induced fluctuations might be easily detected. We conducted the first temporal assessment of benthic communities and the influence of oceanographic parameters between 2013 and 2019 in Fernando de Noronha (FNA), the largest Brazilian oceanic archipelago. We annually sampled benthic communities in FNA’s shallow reefs (2–21 m) using photoquadrats, quantified and gathered organisms in major groups according to their functional roles. We also characterized and tested “sea surface temperature,” “marine heatwaves,” “diffuse attenuation coefficient,” and “wave energy” influence for the same period. The most abundant groups were epilithic algal matrix (EAM; mean annual coverage: 23–60%), macroalgae (15–35%) and calcifiers (15–29%), followed by cyanobacteria (1–37%), suspension/filter-feeders (&amp;lt;2%), zoanthids (&amp;lt;1%) and other invertebrates (&amp;lt;0.1%). EAM was negatively correlated with “marine heatwaves” and positively correlated with “wave energy,” while macroalgae and calcifiers showed opposite responses to “marine heatwaves” and “wave energy,” respectively. Cyanobacteria was positively correlated with “marine heatwaves.” The dominance of EAM and macroalgae was already described for reefs along the Brazilian Province and we demonstrated the persistence of this structure over the years in FNA, with the exception of 2019 when there was a substantial increase of cyanobacteria after a strong marine heatwave. Our results suggest a flickering dynamic between EAM and macroalgae, which vary according to the oceanographic conditions, reinforcing its distinct dynamics from most tropical coral reefs. However, the increase of cyanobacteria added to projections of more frequent and stronger marine heatwaves worldwide indicate possible structural changes in this community. Continued monitoring of community and oceanographic drivers is key for better understanding and predicting changes in important marginal reefs.

Abstract AimThe accumulation of functional diversity in communities is poorly understood. Conveniently, the general dynamic model of island biogeography (GDM) makes predictions for how such diversity might accumulate over time. In this multiscale study of land snail communities on 10 oceanic archipelagos located in various regions of the globe, we test hypotheses of community assembly in systems where islands serve as chronosequences along island ontogeny.LocationTen volcanic archipelagos.Time periodFrom 23 Ma to the present.Major taxa studiedEndemic land snails.MethodsInitially, we assembled geological island characteristics of area, isolation and ontogeny for all studied islands. We then characterized island‐scale biotic variables, including the species diversity and functional diversity of snail communities. From these data, we assessed relationships between island and snail community variables as predicted by the GDM, focusing initially on the islands of the Galápagos archipelago and thereafter with a broader analysis of 10 archipelagoes.ResultsAs in other studies of island assemblages, in Galápagos we find a hump‐shaped curve of species richness, with depauperate snail faunas on early‐ontogeny islands, increasing species richness on mid‐ontogeny islands and low species richness on islands in late ontogeny. We find exceptionally low functional diversity on early‐ontogeny islands that increases through mid‐ontogeny, whereas late‐ontogeny islands exhibit a range of functional diversity. The analysis including all 10 archipelagos indicates a major role of archipelago‐specific factors. In both sets of analyses, functional diversity is exceptionally low on early‐ontogeny islands, and island ontogeny is a significant predictor of morphology.Main conclusionsConsistent patterns of functional diversity across island ontogeny on all examined archipelagos indicate a common role for habitat filtering, ecological opportunity and competition in a diversity of systems, leading to predictable changes in functional diversity and average morphology through island ontogeny, whereas patterns of species richness appear subject to archipelago‐specific factors.

Animal poisoning is one of the greatest conservation threats facing wildlife. In a preliminary study in the oceanic archipelago of the Canary Islands, we showed that the degree of threat from this circumstance was very high-even higher than that reported in other regions of continental Europe. Consequently, a legal framework for the effective prosecution of the crime of wildlife poisoning came into force in 2014 in this region. We present the results of the investigation of 961 animals and 84 baits sent to our laboratory for the diagnosis of animal poisonings during the period 2014–2021. We were able to identify poison as the cause of death in 251 animals and 61 baits. Carbofuran stands out as the main agent used in this archipelago. We have also detected an increasing tendency to use mixtures of several pesticides in the preparation of baits. The entry into operation of two canine patrols has led to the detection of more dead animals in the wild and a greater number of poisoned animals. The percentage of poison positives is significantly higher in areas with lower population density, corresponding to rural environments, as well as in areas with greater agricultural and livestock activity.

ABSTRACT Dozens of marine fish species are known to form spawning aggregations, a behaviour that often increases the species vulnerability to fisheries. Therefore, it is widely recommended for aggregation sites to be considered a conservation priority, and implementation of management measures on those sites is essential. Here, we report for the first time the reproductive behaviour of the marbled grouper Dermatolepis inermis, observed at a lower mesophotic coral ecosystem of Fernando de Noronha, an oceanic tropical archipelago in the southwestern Atlantic. The event was characterised by an aggregation of six adult fish, displaying courtship behaviour and reproductive colouration. We also recorded an aggregation of about 20 dog snappers Lutjanus jocu at the same site, but no reproductive behaviour was observed. Finally, another aggregation was observed in the island’s upper mesophotic reefs, with 25 terminal phase individuals of the Brazilian endemic parrotfish Sparisoma amplum. Our report reinforces the biological importance of mesophotic coral ecosystems, and highlights the urgent need of governmental policies for studying, monitoring, and protecting those reefs.

Oceanic archipelagos are excellent systems for studying speciation, yet inference of evolutionary process requires that the colonization history of island organisms be known with accuracy. Here, we used phylogenomics and patterns of genetic diversity to infer the sequence and timing of colonization of Macaronesia by mainland common chaffinches (Fringilla coelebs), and assessed whether colonization of the different archipelagos has resulted in a species-level radiation. To reconstruct the evolutionary history of the complex we generated a molecular phylogeny based on genome-wide SNP loci obtained from genotyping-by-sequencing, we ran ancestral range biogeographic analyses, and assessed fine-scale genetic structure between and within archipelagos using admixture analysis. To test for a species-level radiation, we applied a probabilistic tree-based species delimitation method (mPTP) and an integrative taxonomy approach including phenotypic differences. Results revealed a circuitous colonization pathway in Macaronesia, from the mainland to the Azores, followed by Madeira, and finally the Canary Islands. The Azores showed surprisingly high genetic diversity, similar to that found on the mainland, and the other archipelagos showed the expected sequential loss of genetic diversity. Species delimitation methods supported the existence of several species within the complex. We conclude that the common chaffinch underwent a rapid radiation across Macaronesia that was driven by the sequential colonization of the different archipelagos, resulting in phenotypically and genetically distinct, independent evolutionary lineages. We recommend a taxonomic revision of the complex that takes into account its genetic and phenotypic diversity.

Abstract The conservation of marine megafauna presents numerous difficulties owing to their high mobility over difficult‐to‐access oceanic areas that impairs the collection of basic, but essential, biological information. The Bryde's whale (Balaenoptera edeni) is one of the most elusive species of baleen whales, and although it is known to be a seasonal visitor to several archipelagos in Macaronesia (the Azores, Madeira, and Canaries), there are no studies regarding its occurrence or geographical connectivity in this area of the Atlantic. A 14‐year photographic database was used to determine short‐term (intra‐seasonal) and long‐term (inter‐annual) Bryde's whale site fidelity and to estimate individual residency times in Madeira, whereas photographic catalogues from Madeira and the Canaries were compared in order to assess large‐scale movements (i.e. on the scale of hundreds of kilometres). In Madeira, 59 individuals were identified, 27 (45.8%) of which were recaptured. Of these, 10 individuals (37.0%) presented short‐term site fidelity and 17 individuals (63.0%) presented long‐term site fidelity, with a maximum recapture interval of 12 years. Lagged identification rates showed that five individuals (SE = 2) remained in the area for 32 days (SE = 108 days) before leaving and not returning during the same year. Seven individuals were seen both in Madeira and the Canaries (catalogue comprising 51 individuals), three of which were identified multiple times in both archipelagos, with a minimum of 43 days between consecutive sightings. This information combined with the fact that this species is commonly sighted accompanied by calves and feeding in both archipelagos highlights the ecological importance of this area for Bryde's whales. This should be taken into consideration by policymakers when implementing conservation measures, where coordination of effort among countries is needed. This study also reinforces the value of using data from platforms of opportunity and of making photographic data open access.