Global diversity of coastal cephalopods: hotspots and latitudinal gradients

Tese de mestrado em Ecologia Marinha, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2017A presente dissertação visa identificar, pela primeira vez, os hotspots globais de diversidade de cefalópodes costeiros, nomeadamente, de chocos (famílias Sepiidae, Sepiolidae, Sepiadariidae e Idiosepiidae), lulas (famílias Loliginidae) e polvos (família Octopodidae) e avaliar os correspondentes gradientes latitudinais de riqueza específica (GLRS). Neste âmbito, foi criada uma base de dados de presenças/ausências, de acordo com as Ecoregiões Marinhas do Mundo, na qual o Oceano Pacífico surge como sendo o mais diverso (com 212 espécies), seguido do Índico (com 151 espécies) e do Atlântico (com 103 espécies). Em contraste, os Oceanos Ártico (com 13 espécies) e Antártico (com 7 espécies) revelaram-se os menos diversos. Das 232 ecoregiões consideradas, o maior valor de diversidade específica foi obtido na ecorregião da Corrente Kuroshio Central (CKC), com 64 espécies, seguido do Mar da China Oriental (MCO), com 59 espécies, e das Filipinas (F), com 48 espécies. Advogo que a localização destes hotspots se encontra relacionada com as teorias de “centro de origem”, “centro de sobreposição” ou “centro de acumulação” postuladas para a região do Arquipélago Indo-Australiano, tendo em conta as particulares condições de produtividade associadas aos dinâmicos sistemas de upwelling próximos da CKC e da ECS. Relativamente à relação entre latitude e diversidade, os picos de diversidade de cefalópodes variaram entre oceanos e apenas as lulas exibiram uma distribuição unimodal. Por outro lado, os chocos, polvos e a classe Cephalopoda revelaram distribuições bimodais, sendo que o maior pico de diversidade se encontrou sempre no hemisfério norte. Defendo que o padrão unimodal das lulas possa ser o resultado do efeito de disponibilidade energética (temperatura à superfície do mar) na fisiologia dos organismos, tal como proposto pela “hipótese energética do ambiente”. Em contrapartida, a generalizada distribuição bimodal poderá estar associada à produtividade oceânica, tal como defendido pela “hipótese espécies-produtividade”, uma vez que áreas altamente produtivas tendem a estar associadas a latitudes temperadas. Em síntese, estes resultados realçam a noção de que a forma e simetria do GLRS não são universais e que não existe um só preditor causal que explique a localização dos hotspots e dos picos de diversidade latitudinal dentro do mesmo taxa.The present dissertation aimed to identify, for the first time, the global hotspots of coastal cephalopod diversity, namely cuttlefishes (families Sepiidae, Sepiolidae, Sepiadariidae and Idiosepiidae), squids (family Loliginidae) and octopuses (family Octopodidae), and assess their latitudinal gradient of species richness (LGRS). I created a presence/absence database, according to Marine Ecoregions of the World, which revealed that the most diverse ocean was the Pacific (with 212 species), followed by the Indian (151 species) and Atlantic (103 species) Oceans. The least diverse were the Artic (13 species) and Southern (7 species) Oceans. Within the 232 ecoregions considered, the highest diversity value was reached in the Central Kuroshio Current (CKC) ecoregion, with 64 species, followed by the East China Sea (ECS, 59 species) and the Eastern Philippines (EP, 48 species). I advocate that these hotspots are linked to the “centre of origin”, “centre of overlap” or “centre of accumulation” hypotheses postulated for the Indo-Australian Archipelago region, together with the particular productivity-rich conditions associated with upwelling system dynamics near CKC and ECS. Regarding the association between latitude and diversity, cephalopod peak of diversity varied among oceans, and only the squids showed a unimodal distribution with latitude. In opposition, cuttlefish, octopods and Cephalopoda revealed bimodal distributions, always with the major peak of diversity in the north hemisphere. I argue that the squid unimodal pattern may be a result of the effect of energy availability (sea surface temperature) in the organism’s physiology, as proposed by the “ambient energy hypothesis”. On the other hand, the widespread bimodal distributions may be linked to ocean productivity (i.e. the “species-productivity hypothesis”) given that highly productive areas tend to be associated with temperate latitudes. Summing up, these findings highlight the notion that the shape and symmetry of LGRS are not universal and there are no single causal predictors to explain hotspot and latitudinal zenith locations within the same taxa

An endemic‐rich island through the eyes of children: Wildlife identification and conservation preferences in São Tomé (Gulf of Guinea)

Species that the public knows and is willing to protect often do not align with international conservation priorities. Assessing perceptions on wildlife is thus essential to guide conservation initiatives, especially in island developing states where native and introduced species often have contrasting values for biodiversity. We used a game to assess the ability of third class students in São Tomé Island (São Tomé and Príncipe, central Africa) to identify wildlife and their conservation preferences. Students correctly identified 28% of the animals shown. Children who were poorer, male or from rural schools were more likely to correctly identify species. Urban children were less successful identifying species endemic to São Tomé and Príncipe than rural children. Conservation preferences were not associated with species identification and instead were justified by subjective species-specific traits, such as attractiveness or profitability. Despite the low identification rates for endemic (10% correct identifications) and threatened birds (2%), children were keen on preserving endemic species, indicating that these might become effective flagships for the unique biodiversity of the island. These results illustrate the need to consider separately the attributes that affect knowledge and willingness to protect, and how both can be used to guide conservation strategies.info:eu-repo/semantics/publishedVersio

Bioluminescence in cephalopods: biodiversity, biogeography and research trends

Numerous terrestrial and marine organisms, including cephalopods, are capable of light emission. In addition to communication, bioluminescence is used for attraction and defense mechanisms. The present review aims to: (i) present updated information on the taxonomic diversity of luminous cephalopods and morphological features, (ii) describe large-scale biogeographic patterns, and (iii) show the research trends over the last 50 years on cephalopod bioluminescence. According to our database (834 species), 32% of all known cephalopod species can emit light, including oegopsid and myopsid squids, sepiolids, octopuses, and representatives of several other smaller orders (bathyteuthids, and the monotypic vampire “squid”, Vampyroteuthis infernalis and ram’s horn “squid”, Spirula spirula). Most species have a combination of photophores present in different locations, of which light organs on the head region are dominant, followed by photophores associated with the arms and tentacles and internal photophores. Regarding the biogeographic patterns of cephalopod species with light organs, the most diverse ocean is the Pacific Ocean, followed by the Atlantic and Indian Oceans. The least diverse are the Southern and the Arctic Oceans. Regarding publication trends, our systematic review revealed that, between 1971 and 2020, 277 peer-reviewed studies were published on bioluminescent cephalopods. Most research has been done on a single species, the Hawaiian bobtail squid Euprymna scolopes. The interest in this species is mostly due to its species-specific symbiotic relationship with the bacterium Vibrio fischeri, which is used as a model for the study of Eukaryote–Prokaryote symbiosis. Because there are many knowledge gaps about the biology and biogeography of light-producing cephalopods, new state-of-the-art techniques (e.g., eDNA for diversity research and monitoring) can help achieve a finer resolution on species’ distributions. Moreover, knowledge on the effects of climate change stressors on the bioluminescent processes is nonexistent. Future studies are needed to assess such impacts at different levels of biological organization, to describe the potential broad-scale biogeographic changes, and understand the implications for food web dynamics

Evidence for the first multi-species shark nursery area in Atlantic Africa (Boa Vista Island, Cabo Verde)

Funding: This research is part of project NGANDU (The Importance of Shark Populations and Sustainable Ocean Use for Human Well-being in Cabo Verde and São Tomé and Príncipe, West Africa) funded by the Portuguese Foundation for Science and Technology (FCT) and the Aga Khan Development Network (AKDN) under grant agreement FCT AGA-KHAN/541746579/2019. All authors acknowledge funding from FCT under the strategic project UIDB/04292/2020 granted to MARE and project LA/P/0069/2020 granted to the Associate Laboratory ARNET. TM acknowledges funding from the strategic project UIDB/00006/2020 granted to CEAUL. CF acknowledges funding from FCT research contract 2020.03704.CEECIND and FCT grant agreement PTDC/CTA-AMB/30226/2017. VP acknowledges funding from FCT PhD grant 2020.05435.BD. CS acknowledges funding from FCT PhD grant SFRH/BD/117890/2016, FCT research grants under PTDC/CTA-AMB/30226/2017 through FCiencias.ID and AGA-KHAN/541746579/2019 through Nova School of Business and Economics. EN acknowledges funding from FCT PhD grant SFRH/BD/135438/2017. JRP acknowledges funding from FCT research contract 2021.01030.CEECIND. JV acknowledges funding from the Intergovernmental Panel on Climate Change (PhD grant, IPCC Scholarship Programme–Prince Albert II of Monaco Foundation) and the Camões–Instituto da Cooperação e da Língua, I.P. (Scholarship Programme).This study describes the first potential multi-species shark nursery area in Atlantic Africa (Sal Rei Bay – SRB, Boa Vista Island, Cabo Verde). From August 2016 to September 2019, 6162 neonates and juveniles of 5 different shark species were observed in SRB using beach gillnet-based bycatch surveys, namely milk (Rhizoprionodon acutus; n= 4908), scalloped hammerhead (Sphyrna lewini; n= 1035), blacktip (Carcharhinus limbatus; n=115), Atlantic weasel (Paragaleus pectoralis; n= 93) and nurse (Ginglymostoma cirratum; n= 12) sharks. Except for nurse sharks, significant seasonal variations in shark relative abundance were observed, with higher levels being recorded during summer and autumn. These findings, together with local knowledge (interviews to fishermen), denote the consistent use of SRB by juvenile sharks and its preference relative to other areas in the region. Ensuring the protection and conservation of SRB nursery area is especially relevant as, according to IUCN, all identified shark species are threatened with extinction over the near-future – in particular, scalloped hammerheads (critically endangered) and Atlantic weasel sharks (endangered). The effective protection of SRB will not only support the conservation of shark populations, but also of other charismatic fauna (e.g., loggerhead turtles) and broader benthic and pelagic ecosystems.Publisher PDFPeer reviewe

Bioluminescence in cephalopods: biodiversity, biogeography and research trends

Numerous terrestrial and marine organisms, including cephalopods, are capable of light emission. In addition to communication, bioluminescence is used for attraction and defense mechanisms. The present review aims to: (i) present updated information on the taxonomic diversity of luminous cephalopods and morphological features, (ii) describe large-scale biogeographic patterns, and (iii) show the research trends over the last 50 years on cephalopod bioluminescence. According to our database (834 species), 32% of all known cephalopod species can emit light, including oegopsid and myopsid squids, sepiolids, octopuses, and representatives of several other smaller orders (bathyteuthids, and the monotypic vampire “squid”, Vampyroteuthis infernalis and ram’s horn “squid”, Spirula spirula). Most species have a combination of photophores present in different locations, of which light organs on the head region are dominant, followed by photophores associated with the arms and tentacles and internal photophores. Regarding the biogeographic patterns of cephalopod species with light organs, the most diverse ocean is the Pacific Ocean, followed by the Atlantic and Indian Oceans. The least diverse are the Southern and the Arctic Oceans. Regarding publication trends, our systematic review revealed that, between 1971 and 2020, 277 peer-reviewed studies were published on bioluminescent cephalopods. Most research has been done on a single species, the Hawaiian bobtail squid Euprymna scolopes. The interest in this species is mostly due to its species-specific symbiotic relationship with the bacterium Vibrio fischeri, which is used as a model for the study of Eukaryote–Prokaryote symbiosis. Because there are many knowledge gaps about the biology and biogeography of light-producing cephalopods, new state-of-the-art techniques (e.g., eDNA for diversity research and monitoring) can help achieve a finer resolution on species’ distributions. Moreover, knowledge on the effects of climate change stressors on the bioluminescent processes is nonexistent. Future studies are needed to assess such impacts at different levels of biological organization, to describe the potential broad-scale biogeographic changes, and understand the implications for food web dynamics

The significance of cephalopod beaks as a research tool: An update

The use of cephalopod beaks in ecological and population dynamics studies has allowed major advances of our knowledge on the role of cephalopods in marine ecosystems in the last 60 years. Since the 1960's, with the pioneering research by Malcolm Clarke and colleagues, cephalopod beaks (also named jaws or mandibles) have been described to species level and their measurements have been shown to be related to cephalopod body size and mass, which permitted important information to be obtained on numerous biological and ecological aspects of cephalopods in marine ecosystems. In the last decade, a range of new techniques has been applied to cephalopod beaks, permitting new kinds of insight into cephalopod biology and ecology. The workshop on cephalopod beaks of the Cephalopod International Advisory Council Conference (Sesimbra, Portugal) in 2022 aimed to review the most recent scientific developments in this field and to identify future challenges, particularly in relation to taxonomy, age, growth, chemical composition (i.e., DNA, proteomics, stable isotopes, trace elements) and physical (i.e., structural) analyses. In terms of taxonomy, new techniques (e.g., 3D geometric morphometrics) for identifying cephalopods from their beaks are being developed with promising results, although the need for experts and reference collections of cephalopod beaks will continue. The use of beak microstructure for age and growth studies has been validated. Stable isotope analyses on beaks have proven to be an excellent technique to get valuable information on the ecology of cephalopods (namely habitat and trophic position). Trace element analyses is also possible using beaks, where concentrations are significantly lower than in other tissues (e.g., muscle, digestive gland, gills). Extracting DNA from beaks was only possible in one study so far. Protein analyses can also be made using cephalopod beaks. Future challenges in research using cephalopod beaks are also discussed.info:eu-repo/semantics/publishedVersio

The significance of cephalopod beaks as a research tool: An update

The use of cephalopod beaks in ecological and population dynamics studies has allowed major advances of our knowledge on the role of cephalopods in marine ecosystems in the last 60 years. Since the 1960’s, with the pioneering research by Malcolm Clarke and colleagues, cephalopod beaks (also named jaws or mandibles) have been described to species level and their measurements have been shown to be related to cephalopod body size and mass, which permitted important information to be obtained on numerous biological and ecological aspects of cephalopods in marine ecosystems. In the last decade, a range of new techniques has been applied to cephalopod beaks, permitting new kinds of insight into cephalopod biology and ecology. The workshop on cephalopod beaks of the Cephalopod International Advisory Council Conference (Sesimbra, Portugal) in 2022 aimed to review the most recent scientific developments in this field and to identify future challenges, particularly in relation to taxonomy, age, growth, chemical composition (i.e., DNA, proteomics, stable isotopes, trace elements) and physical (i.e., structural) analyses. In terms of taxonomy, new techniques (e.g., 3D geometric morphometrics) for identifying cephalopods from their beaks are being developed with promising results, although the need for experts and reference collections of cephalopod beaks will continue. The use of beak microstructure for age and growth studies has been validated. Stable isotope analyses on beaks have proven to be an excellent technique to get valuable information on the ecology of cephalopods (namely habitat and trophic position). Trace element analyses is also possible using beaks, where concentrations are significantly lower than in other tissues (e.g., muscle, digestive gland, gills). Extracting DNA from beaks was only possible in one study so far. Protein analyses can also be made using cephalopod beaks. Future challenges in research using cephalopod beaks are also discussed

The role of corals on the abundance of a fish ectoparasite in the Great Barrier Reef

Gnathiid isopods, common fish ectoparasites, can affect fish physiology, behaviour and survival. Gnathiid juveniles emerge from the benthos to feed on fish blood. In the Caribbean, gnathiids are positively associated with dead coral and negatively associated with live coral, due to coral predation on gnathiids. However, such interactions were unstudied in the Great Barrier Reef (GBR). Due to recent extreme weather events (two cyclones and one mass warm-water coral bleaching event, 2014–2016), it is now urgent to understand the role of corals on the abundance of these ectoparasites. Here, to understand parasite–coral dynamics at the micro-habitat level, we examined substrate associations of gnathiid isopods on Lizard Island (GBR) using demersal plankton emergence traps. Additionally, we determined whether two abundant hard coral species, Goniopora lobata and Pocillopora damicornis, predate on gnathiids in a laboratory experiment using containers with gnathiids and fragments from each coral species or dead coral as controls. The abundance of gnathiids over natural substrates was higher for dead compared to live hard coral and sand, but not live soft coral. Moreover, we found that free-swimming gnathiids decreased in containers with live coral compared to dead coral controls. This was attributed to predation as we also directly observed a coral ingesting a gnathiid. Our results suggest that dead coral is a suitable microhabitat for gnathiids, but that live coral is not since live corals can predate on gnathiids. We propose that following extreme events, such as cyclones and heat waves, gnathiids might benefit from more dead coral substrate and a decrease in predation by the reduction in coral cover on the reef. We advocate that an increase in the frequency of extreme events may have cascading effects for the fish population through changes in the population of benthos-dependent ectoparasites

Global patterns of coastal cephalopod richness: hotspots and latitudinal gradients

Cephalopod International Advisory Council Conference (CIAC 2018) : Cephalopod Research Across Scales: From Molecules to Ecosystems, 12-16 November 2018, St. Petersburg, Florida, USA.-- 1 pageThe present study aimed to identify, for the first time, the global hotspots of coastal cephalopod richness, namely cuttlefishes (families Sepiidae, Sepiolidae, Sepiadariidae and Idiosepiidae), squids (family Loliginidae) and octopuses (family Octopodidae), and to assess their latitudinal gradient of species richness (LGRS). A presence/absence database was created according to Marine Ecoregions of the World, which revealed that the most diverse ocean was the Pacific(with 212 species), followed by the Indian (151 species) and Atlantic (103 species) Oceans. Within the 232 ecoregions considered, the highest cephalopod richness value was reached in the Central Kuroshio Current ecoregion, with 64 species, followed by theEast China Sea (59 species) and the Eastern Philippines (48 species). Nonetheless, the location of the hotspots varied greatly among the different taxonomic groups. Regarding the association between latitude and species richness, the peak of cephalopod richness varied among oceans, and only the squids showed a unimodal distribution with latitude. In contrast, cuttlefish, octopods and all cephalopods together revealed bimodal distributions, always with the major peak of species richness in the northern hemisphere. These findings highlight the notion that the shape and symmetry of LGRS are not universal –i.e. there are no single causal predictors to explain the latitudinal zenith locations within the same taxaPeer Reviewe