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Study area in the western Canary Islands. Common bottlenose dolphins were photographed in four Special Areas of Conservation (shaded): Mar de las Calmas (ES7020057) off El Hierro; Franja marina Santiago-Valle Gran Rey (ES7020123) off La Gomera; Franja marina de Fuencaliente (ES7020122) off La Palma and Franja marina Teno-Rasca (ES7020017) off Tenerife
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A total of 313 individual common bottlenose dolphins Tursiops truncatus was photo-identified in four Special Areas of Conservation (SACs) in the western Canary Islands, Spain (El Hierro, La Palma, La Gomera and Tenerife), over a 10-year period (2001–2011). Of these, 36 individuals were resighted subsequently off two or more different islands, deter...
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Citations
... Many cetacean species inhabit and roam these oceanic waters, representing not only a hotspot of cetacean abundance and diversity [33] but also an important biological corridor for these large marine mammals due to their high dispersal capacities. Bottlenose dolphin populations observed in different SACs from the Canary Islands show high site fidelity patterns and are greater than populations of other archipelagos (e.g., Hawaii or Bahamas; [34]). Several individuals have been resighted off two or more islands and even in other archipelagos (Madeira), providing evidence of the long-distance movements (≈500 km) that these dolphins can undertake [34,35]. ...
... Bottlenose dolphin populations observed in different SACs from the Canary Islands show high site fidelity patterns and are greater than populations of other archipelagos (e.g., Hawaii or Bahamas; [34]). Several individuals have been resighted off two or more islands and even in other archipelagos (Madeira), providing evidence of the long-distance movements (≈500 km) that these dolphins can undertake [34,35]. Nevertheless, to date, these populations remain unstudied in terms of genetic structure, connectivity with other regions, and ecotype assessment. ...
... Moreover, data relating to North-East Atlantic Ocean (NEAO) bottlenose dolphins were added to our analysis to study the phylogeographic relationships and possible connectivity with the other populations from the North-East Atlantic basin. Since no levels of genetic structure were found in other archipelagos (within and between Azores and Madeira) of the Macaronesian region [18], the high dispersal of Canarian bottlenose dolphins [34,35], and the broad connectivity of the pelagic ecotype in the North-East Atlantic [18,20], we hypothesized that none or negligible levels of genetic structure should be observed within the Canary Islands, clustering with the pelagic ecotype of the North-East Atlantic. ...
Simple Summary
The common bottlenose dolphin, Tursiops truncatus, is a worldwide cetacean species essential for marine ecosystems’ health and balance. Understanding the genetic connectivity and structure of different populations is crucial for the correct management and conservation of a species, such as designing Special Areas of Conservation or Marine Protected Areas. In this study, we described the genetic composition of 49 bottlenose dolphins from the Canary Islands, which were previously unstudied, and compared them with individuals from the rest of the North-East Atlantic Ocean. The results showed that Canarian bottlenose dolphins have a remarkably diverse genetic composition, and this population is possibly part of a larger oceanic population in the North Atlantic. Therefore, the studied Special Areas of Conservation in the Canary Islands may correspond to a hotspot of genetic diversity and could be a strategic area for the conservation of the species.
Abstract
In recent decades, worldwide cetacean species have been protected, but they are still threatened. The bottlenose dolphin (Tursiops truncatus) is a vulnerable keystone species and a useful bioindicator of the health and balance of marine ecosystems in oceans all over the world. The genetic structure of the species is shaped by their niche specialization (along with other factors), leading to the classification of two ecotypes: coastal and pelagic. In this study, the genetic diversity, population structure, and ecotypes of bottlenose dolphins from the Canary Islands were assessed through the analysis of 49 new samples from biopsies and from stranded animals using the 636 bp portion of the mitochondrial control region and 343 individuals from databases (n = 392). The results reveal high genetic diversity in Canarian bottlenose dolphins (Hd = 0.969 and π = 0.0165) and the apparent lack of population genetic structure within this archipelago. High genetic structure (Fst, Φst) was found between the Canary Islands and coastal populations, while little to no structure was found with the pelagic populations. These results suggest that Canarian bottlenose dolphins are part of pelagic ecotype populations in the North Atlantic. The studied Special Areas of Conservation in the Canary Islands may correspond to a hotspot of genetic diversity of the species and could be a strategic area for the conservation of the oceanic ecotype of bottlenose dolphins.
... To date, there are no scientific publications about bottlenose dolphin habitat use in this Archipelago, and little is generally known about this species' reproductive behavior around oceanic islands. The lack of information about potential critical habitats within which animals socialize, breed, and take care of their young may hamper the development of appropriate management protocols of tourist activities, as well as assessments of present and future anthropogenic impacts (Silva et al., 2008;Tobeña et al., 2014). Most information comes from coastal populations, which indicates that home ranges vary greatly in bottlenose dolphins and are mainly linked to food availability (Stevick et al., 2002;Viddi et al., 2010;Martínez-Serrano et al., 2011;Sprogis et al., 2016). ...
... Along the Atlantic coast of Spain there is evidence that coastal and offshore populations of bottlenose dolphins have different diets, with offshore dolphins characterized by lower values of δ 13 C and δ 15 N (Fernández et al. 2011). It not clear whether there is more than one ecotype present in Macaronesia (Tobeña et al. 2014), and this may require further exploration. In contrast, no trends in TP or in the baseline were apparent for striped and spotted dolphins in this study, further supporting a differential impact of environmental changes on each species. ...
... Along the Atlantic coast of Spain there is evidence that coastal and offshore populations of bottlenose dolphins have different diets, with offshore dolphins characterized by lower values of δ 13 C and δ 15 N (Fernández et al. 2011). It not clear whether there is more than one ecotype present in Macaronesia (Tobeña et al. 2014), and this may require further exploration. In contrast, no trends in TP or in the baseline were apparent for striped and spotted dolphins in this study, further supporting a differential impact of environmental changes on each species. ...
Dolphins play a key role in marine food webs as predators of mid-trophic-level consumers. Because of their mobility and relatively long life span, they can be used as indicators of large-scale changes in the ecosystem. In this study, we calculated the trophic position (TP) of 5 dolphin species from the Canary, Madeira and Azores Islands using bulk and compound-specific stable isotope ratios from muscle tissue to assess trophic adaptations to recent changes in the availability of feeding resources. Dolphin TP values were then compared with those of 7 other species of cetaceans from this region. Analysis of stable nitrogen isotopes in amino acids of the common dolphin indicated non-significant effects of changes in the basal resources of the food web and thus supported the use of bulk samples for TP estimations. Dolphins occupied an intermediate TP (mean: 3.91 to 4.20) between fin (3.25) and sperm whales (4.95). Species-specific TP were equivalent among islands. However, TP increased for the common dolphin and decreased for the striped dolphin (the latter also becoming more oceanic) between 2000 and 2018 in the Canary Islands. These results suggest different impacts of recent changes in the oceanography and in the pelagic food web of the Macaronesian region on the trophic ecology of dolphin species.
... MPAs designed to protect reef species can partly protect pelagic species that use both nearshore and pelagic habitats differently for foraging, breeding, nurseries, commuting, and resting (Bucaram et al., 2018;Hays et al., 2020a). Some far-ranging species use nearshore or onshore habitats for breeding or juvenile life stages but then use pelagic habitats for feeding or adult life history stages (McCauley et al., 2012b;Tobeña et al., 2014). Some nearshore species regularly travel offshore and provide important ecosystem links through nutrient subsidies (e.g., seabirds bring pelagic nutrients to islands; McCauley et al., 2012a; reef sharks transfer nutrients within coral reef systems; Williams et al., 2018). ...
... Some species use both nearshore and pelagic habitats regularly. Bottlenose dolphins and melon-headed whales use both nearshore and pelagic regions for resting and foraging (Baumann-Pickering et al., 2015;Tobeña et al., 2014). Bottlenose dolphins are represented by two ecotypes, coastal and oceanic, that may occur in adjacent areas, but fulfill specific niches in distinct habitats (Díaz-Gamboa et al., 2018;Zaeschmar et al., 2020). ...
Marine protected area (MPA) designs, including large-scale MPAs (LSMPAs; >150,000 km2), mobile MPAs (fluid spatiotemporal boundaries), and MPA networks, may offer different benefits to species and could enhance protection by encompassing spatiotemporal scales of animal movement. We sought to understand how well LSMPAs could benefit nine highly-mobile marine species in the tropics now and into the future by: 1) evaluating current range overlap within a LSMPA; 2) evaluating range overlap under climate change projections; and 3) evaluating how well theoretical MPA designs benefit these nine species. We focused on Palmyra Atoll and Kingman Reef, a 2000 km2 area within the 1.2 million km2 U.S. Pacific Remote Islands Marine National Monument (PRIMNM) that contains marine megafauna (reef and pelagic fishes; sea turtles; seabirds; cetaceans) reflecting different behaviors and habitat use. Our approach is useful for evaluating the effectiveness of the Palmyra-Kingman MPA and PRIMNM in protecting these species, and tropical LSMPAs in general, and for informing future MPA design. Stationary MPAs provided protection at varying scales. Reef manta rays (Mobula alfredi), grey reef sharks (Carcharhinus amblyrhynchos), green sea turtles (Chelonia mydas), and bottlenose dolphins (Tursiops truncatus) had overall small ranges (
... However, few studies have linked individual habitat and diet use to compartmentalized rather than coupled food webs but see 9,13,14 , and it is unknown how widespread compartmentalization is in contrast to coupling. Common bottlenose dolphins (Tursiops truncatus truncatus; hereafter referred to as dolphins) are globally ubiquitous, habitat generalists, and many nearshore and offshore populations have large ranges with extensive movements encompassing multiple habitats [23][24][25] . Dolphin populations that inhabit estuarine waters often show high site fidelity and individual habitat specialization, even if they are largely dietary generalists within that narrow habitat range 18,[26][27][28][29] . ...
... The limited movements of estuarine dolphins may be driven at least in part by the high abundance of resources found in these habitats 65,66 such that estuarine dolphins may only require relatively small ranging patterns to meet their nutritional requirements. In nearshore and offshore habitats, where prey are more patchily distributed, dolphins likely need larger ranges to forage 24,67 . Social factors may also facilitate constrained ranges, which remain consistent among generations as prey capture techniques are learned and often specific to particular prey at certain sites 21,29,35 . ...
Mobile, apex predators are commonly assumed to stabilize food webs through trophic coupling across spatially distinct habitats. The assumption that trophic coupling is common remains largely untested, despite evidence that individual behaviors might limit trophic coupling. We used stable isotope data from common bottlenose dolphins across the Gulf of Mexico to determine if these apex predators coupled estuarine and adjacent, nearshore marine habitats. δ ¹³ C values differed among the sites, likely driven by environmental factors that varied at each site, such as freshwater input and seagrass cover. Within most sites, δ ¹³ C values differed such that dolphins sampled in the upper reaches of embayments had values indicative of estuarine habitats while those sampled outside or in lower reaches of embayments had values indicative of marine habitats. δ ¹⁵ N values were more similar among and within sites than δ ¹³ C values. Data from multiple tissues within individuals corroborated that most dolphins consistently used a narrow range of habitats but fed at similar trophic levels in estuarine and marine habitats. Because these dolphins exhibited individual habitat specialization, they likely do not contribute to trophic coupling between estuarine and adjacent marine habitats at a regional scale, suggesting that not all mobile, apex predators trophically couple adjacent habitats.
... Moreover, of the 14 odontocetes observed during the 12 years of studies, three of them dominated the sightings (75.58% of the total sightings), namely, G. macrorhynchus, T. truncatus, and S. frontalis. The first two species have been well-studied in the Canary Islands (Morales- Herrera, 2015;Servidio et al., 2019), especially in the waters surrounding Tenerife Carrillo et al., 2006Pérez-Vallazza et al., 2008;Tobeña et al., 2014), showing similar spatial distribution in all years of the study. This suggests that environmental fluctuations do not affect the presence of those resident cetaceans. ...
The waters of the Canary Islands are considered a hotspot for marine biodiversity, especially regarding cetacean species. Based on this fact, this study pays attention to the spatial distribution pattern of cetacean species and the conservation role of the Natura 2000 Network, a set of Special Areas of Conservation (SACs), which were defined mainly based on data compiled in 1996, under the framework of the European Habitats Directive. In recent years, the declaration of conservation areas for cetaceans between the Tenerife—La Gomera Islands by two global conservation programs, Mission Blue (“Hope Spots”) and Whale Heritage Site (“Whale Sanctuary”) sent clear signals of scientific and social interest to promote better protection of the cetacean species in the Canary Islands. The main aim of the designated SACs is the conservation of its biological and ecological diversity, ensuring the long-term survival of the target species in the waters around islands. In this case, the enactment of the SACs was based only on the sparse data available for the common bottlenose dolphin, Tursiops truncatus. This study shows that the spatial distribution of cetaceans in the Canary archipelago generated from a large database of cetacean sightings, from 2007 to 2018. The results obtained show the main marine areas where the different cetacean species are distributed around the different islands of the archipelago. The spatial distribution maps of the cetacean species, when compared with the existing SACs of the Natura 2000, show the need to extend these SACs into the open sea to include more cetacean species and a larger number of individuals for better conservation of the endangered marine mammals. As a consequence, some suggestions were proposed to improve and update the role of SACs in European Northeast Atlantic waters as a key environmental tool for cetacean conservation. The data supporting the recent declarations of these two new milestones the “Hope Spot” and the “Whale Sanctuary” enhance more keystone information to promote a large marine protected area in the Eastern Atlantic Ocean, such as the “Macaronesian Biodiversity and Ecological Migration Corridor for Cetaceans,” a conservation figure that has been already proposed in the scientific literature as a deserving candidate of governmental regulations and policies by Portugal and Spain; it would also require joint cross-border cooperation efforts for marine spatial planning.
... Their home range can vary from small to large displacements (Ballance, 1992;Robinson et al., 2012) depending on food availability, reproductive cycle, season and calf care (Bearzi and Politi, 1999;Würsig et al., 1991). Bottlenose dolphins in the Canary Islands are highly mobile within the archipelago (Tobeña et al., 2014). However, and despite the current insufficient information to identify any ecotypes, there might be individuals with relatively small home ranges, showing mainly local movements, which are dependent on specific conditions more sensitive to climate change. ...
Over the last decades global warming has caused an increase in ocean temperature, acidification and oxygen loss which has led to changes in nutrient cycling and primary production affecting marine species at multiple trophic levels. While knowledge about the impacts of climate change in cetacean's species is still scarce, practitioners and policymakers need information about the species at risk to guide the implementation of conservation measures.
To assess cetacean's vulnerability to climate change in the biogeographic region of Macaronesia, we adapted the Marine Mammal Climate Vulnerability Assessment (MMCVA) method and applied it to 21 species management units using an expert elicitation approach.
Results showed that over half (62%) of the units assessed presented Very High (5 units) or High (8 units) vulnerability scores. Very High vulnerability scores were found in archipelago associated units of short-finned pilot whales (Globicephala macrorhynchus) and common bottlenose dolphins (Tursiops truncatus), namely in the Canary Islands and Madeira, as well as Risso's dolphins (Grampus griseus) in the Canary Islands. Overall, certainty scores ranged from Very High to Moderate for 67% of units.
Over 50% of units showed a high potential for distribution, abundance and phenology changes as a response to climate change.
With this study we target current and future information needs of conservation managers in the region, and guide research and monitoring efforts, while contributing to the improvement and validation of trait-based vulnerability approaches under a changing climate.
... The bottlenose dolphin is a widespread species that occurs in all of the regions in the study area, and has resident populations in at least some of them (Silva et al. 2009, Augusto et al. 2011, Tobeña et al. 2014, Dinis et al. 2016). As it is often associated with coastal habitats, the bottlenose dolphin has become one of the most-studied cetacean species worldwide (Wells & Scott 2009). ...
... It is crucial to gain a better understanding of the ranging patterns of this species in order to establish suitable conservation measures. Apart from small scale movements of bottlenose dolphin studied in greater depth (e.g., Reynolds, Wells & Eide, 2000;Silva et al., 2008;Tobeña et al., 2014;Hwang et al., 2014;Dinis et al., 2016), information from long-distance and inter-archipelagos movements is scarce. Insufficient information on long-distance movements may result in higher emphasis on residency (Bearzi, Bonizzoni & Gonzalvo, 2011), when in fact individuals may leave the study area more frequently than initially thought. ...
... Previous studies of pelagic bottlenose dolphin populations in the NE Atlantic area suggested that these populations have a high gene flow and are genetically less differentiated (Querouil et al., 2007;Louis et al., 2014). Additionally, different residency patterns and individual movements within each archipelago were identified for the Azores (Silva et al., 2008), the Canary Islands (Tobeña et al., 2014) and Madeira (Dinis et al., 2016), with just a portion of the individuals being classified as residents. These results indicate large individual home ranges, but there is no evidence of the connectivity of the populations between these oceanic archipelagos. ...
... If doubts persisted, a third experienced researcher would double-check. In the catalogue compiled by BIOECOMAC, dorsal fin images were entered into a digital database using the software Darwin 2.0 ( c Eckerd College Dolphin Research Group), a trailing edge contour was extracted, which was identifiable from both sides (Auger-Méthé & Whitehead, 2007), and the software was used to assist the matching of individual dolphins (Tobeña et al., 2014). ...
Wide-ranging connectivity patterns of common bottlenose dolphins (Tursiops trunca-tus) are generally poorly known worldwide and more so within the oceanic archipelagos of Macaronesia in the North East (NE) Atlantic. This study aimed to identify long-range movements between the archipelagos of Macaronesia that lie between 500 and 1,500 km apart, and between Madeira archipelago and the Portuguese continental shelf, through the compilation and comparison of bottlenose dolphin's photo-identification catalogues from different regions: one from Madeira (n = 363 individuals), two from different areas in the Azores (n = 495 and 176), and four from different islands of the Canary Islands (n = 182, 110, 142 and 281), summing up 1791 photographs. An additional comparison was made between the Madeira catalogue and one catalogue from Sagres, on the southwest tip of the Iberian Peninsula (n = 359). Results showed 26 individual matches, mostly between Madeira and the Canary Islands (n = 23), and between Azores and Madeira (n = 3). No matches were found between the Canary Islands and the Azores, nor between Madeira and Sagres. There were no individuals identified in all three archipelagos. The minimum time recorded between sightings in two different archipelagos (≈ 460 km apart) was 62 days. Association patterns revealed that the individuals moving between archipelagos were connected to resident, migrant and transient individuals in Madeira. The higher number of individuals that were re-sighted between Madeira and the Canary Islands can be explained by the relative proximity of these two archipelagos. This study shows the first inter-archipelago movements of bottlenose dolphins in the Macaronesia region, emphasizing the high mobility of this species and supporting the high gene flow The dynamics of these long-range movements strongly denotes the need to review marine protected areas established for this species in each archipelago, calling for joint resolutions from three autonomous regions belonging to two EU countries.
