An extensive review of cephalopod fauna in the Central and North Atlantic coast of Africa was performed based on material collected during 10 research cruises in these waters. In the Canary Current Large Marine Ecosystem (CCLME) area, a total of 378,377 cephalopod specimens was collected from 1247 bottom trawl stations. Of those specimens, 300 were sampled for subsequent identification in the laboratory and found to belong to 65 different species and 23 families. After an exhaustive review of the existing literature on the cephalopods and new data obtained from the surveys, an updated checklist of 138 species was generated for the CCLME area. Our knowledge of the known geographic distribution ranges of several species has been expanded: Muusoctopus januarii has been sighted from Guinea–Bissau waters, passing through Western Sahara, to Morocco waters for the first time; Lepidoteuthis grimaldii and Octopus salutii have been sighted off Morocco waters for the first time; Austrorossia mastigophora, Abralia (Heterabralia) siedleckyi, Abralia (Pygmabralia) redfieldi and Sepiola atlantica have been cited off Western Sahara waters for the first time; Magnoteuthis magna, Abralia (Asteroteuthis) veranyi and Octopoteuthis megaptera have been sighted off Moroccan and Western Sahara waters for the first time; Ancistroteuthis lichtensteinii, Opisthoteuthis grimaldii, Onykia robsoni, Muusoctopus levis and Bathypolypus valdiviae have been cited in the Guinea–Bissau coast for the first time; the northern geographic limit of Bathypolypus ergasticus has been expanded to Morocco, Western Sahara and Mauritania and southward to Guinea–Bissau waters. The presence of Muusoctopus johnsonianus in Senegalese waters has been reported for the first time. A Chtenopteryx sicula specimen was reported in Western Sahara waters. A specimen belonging to the poorly known Cirrothauma murrayi species was found in South Moroccan waters. Amphitretus pelagicus, a probably cosmopolitan species, has been reported in the Western Sahara and Guinea–Bissau waters. Some species that were previously recorded in the area, Sepia angulata, Sepia hieronis, Heteroteuthis dagamensis, Helicocranchia joubini and Tremoctopus gelatus, were removed from the final checklist and considered to be not present in the CCLME area. Cycloteuthis akimushkini was substituted with Cycloteuthis sirventi, its senior synonym, in the final checklist. Similarly, Mastigoteuthis flammea and Mastigoteuthis grimaldii were substituted with Mastigoteuthis agassizii.

Metal concentrations in coastal zones are a critical study subject since anthropogenic activities surrounding these zones are increasing and affecting environmental concentrations of metals. Macroalgae have been used as biomonitors since they can act as indicators of metal concentrations in the water column. Tissue samples of three abundant macroalgae species (Spyridia filamentosa, Padina mexicana and Ulva ohnoi) were collected from three sites with different anthropogenic impacts at La Paz Bay and Guaymas Bay, Mexico, during three contrasting seasons (dry, rainy and cold) in the year 2016. Tissue concentrations of iron (Fe), manganese (Mn), copper (Cu), zinc (Zn), nickel (Ni), cadmium (Cd) and lead (Pb) were determined by atomic absorption spectrophotometry. The highest concentrations were found in S. filamentosa inhabiting both bays. The highest Cd and Mn concentrations were recorded in algae from La Paz Bay, while the highest concentrations of Cu, Zn, Pb and Fe were recorded in algae from Guaymas Bay. Metal concentrations varied seasonally; the highest Fe, Cu, Zn, Ni and Pb levels were recorded in the cold season in algae from both bays. S. filamentosa concentrated more Fe, Ni, Cu, Zn and Pb, while P. mexicana and U. ohnoi showed higher Mn and Cd. Therefore, S. filamentosa proved to be the most suitable indicator of metal concentrations, followed by P. mexicana and U. ohnoi. The high metal concentrations recorded in algae from San Juan de la Costa, La Paz Bay, are related to mining activities, whereas those in algae from Guaymas Bay are related to canneries, maritime traffic and others.

Understanding the structure and richness of natural communities is a fundamental goal of marine ecology, and foundation species such as large macroalgae have a disproportionate role in structuring biodiversity. However, high-resolution information on assemblages associated with macroalgae is lacking for many species and regions. Saccorhiza polyschides is a warm-temperate kelp with a relatively short lifespan (12–18 months), large thallus and bulbous holdfast offering habitat for diverse assemblages. In the UK, S. polyschides populations are thought to have proliferated recently. Here, we quantified the density and habitat structure provided by S. polyschides along a gradient of wave exposure within Plymouth Sound, and examined the composition and diversity of associated faunal assemblages. Density varied significantly between sites but not by wave exposure, while biometric measurements were generally highly variable. Senescing holdfasts from sporophytes offered valuable habitat, with high abundance and richness of associated assemblages, although these varied markedly between sporophytes and sites. Faunal abundance, taxon richness and diversity were significantly higher at fully exposed sites than at moderately exposed sites. Internal volume of holdfasts was positively correlated with faunal abundance and taxon richness. We recorded more than 27 distinct taxa and up to ~600 individuals within a single holdfast. Taxa included three fish species, including a novel observation of the pipefish Nerophis lumbriciformis. Further work is needed to examine seasonality in habitat structure and associated diversity patterns but our study demonstrates that even remnant holdfasts from decaying sporophytes represent a valuable microhabitat that may provide shelter, protection and food during winter.

The occurrence of 19 cetacean species along the German North Sea coastline as well as the lower reaches of the major rivers discharging into the German Bight is reviewed for the period 1604–2017 based on records of dead animals, either stranded dead or put to death. The harbour porpoise (Phocoena phocoena) is considered the most abundant and only native species in German coastal and riverine waters. Based on written sources its presence can be traced back to at least 1651, although with statistical data only available from 1990. Finds of further 18 species have been documented: white-beaked dolphin (Lagenorhynchus albirostris), bottlenose dolphin (Tursiops truncatus), Atlantic white-sided dolphin (Lagenorhynchus acutus), common dolphin (Delphinus delphis), striped dolphin (Stenella coeruleoalba), Risso's dolphin (Grampus griseus), long-finned pilot whale (Globicephala melas), killer whale (Orcinus orca), beluga whale (Delphinapterus leucas), narwhal (Monodon monoceros), Sowerby's beaked whale (Mesoplodon bidens), northern bottlenose whale (Hyperoodon ampullatus), sperm whale (Physeter macrocephalus), minke whale (Balaenoptera acutorostrata), sei whale (Balaenoptera borealis), fin whale (Balaenoptera physalus), blue whale (Balaenoptera musculus) and humpback whale (Megaptera novaeangliae). This review corrects several false species assignments earlier introduced in literature based on incorrect scientific or ambiguous German vernacular names and recovers lost records of beluga whale, northern bottlenose whale, sperm whale and fin whale.

Since the taxonomic revision of the Ophidiasteridae by H.L. Clark (1921), in which 20 genera were recognized as valid, several new genera and species were included in this family, and the boundaries between some of them became largely arbitrary. This also applies to Narcissia Gray, 1840, whose morphology and taxonomy are still very poorly understood today. The main goals of this research were: review the taxonomy of the genus Narcissia, from morphological studies; redescribe N. trigonaria Sladen, 1889 s. str.; characterize N. canariensis (d'Orbigny, 1839) and N. gracilis A.H. Clark, 1916, the two valid species most similar to N. trigonaria; review the validity of N. ahearnae Pawson, 2007 and N. trigonaria var. helenae Mortensen, 1933; review the validity of N. gracilis malpeloensis Downey, 1975. Altogether 370 specimens were analysed. All morphological structures of taxonomic importance have been illustrated, and, for the first time, the internal characters of this group were studied, from electron microscopy and microtomography. A new diagnosis for the genus Narcissia was constructed. Narcissia trigonaria was redescribed from a large specimen, from the type locality (Bahia, Brazil). Narcissia ahearnae is considered a valid species, and N. canariensis and N. trigonaria distinct entities. Narcissia trigonaria var. helenae is placed in the synonymy of N. trigonaria, and N. gracilis malpeloensis into the synonymy of N. gracilis. The dataset obtained in this work is by far the most complete acquired for the genus Narcissia.

The ability to acclimate quickly to changing environmental conditions is important for sessile organisms that cannot move to areas with more favourable conditions. Sponges are known to exhibit considerable phenotypic plasticity in response to environmental variability. However, most studies examining differences in sponge morphology have looked at spatial variation in morphological characteristics by comparing sponges at sites with differing environmental conditions. Here we explored the potential of two intertidal sponge species (Halichondria panicea and Hymeniacidon perlevis) to show seasonal acclimation to changing environmental conditions at two sites on the Welsh coast, UK. Both species had a higher proportion of inorganic tissue content in winter months, which correlated with higher levels of wave action and lower temperature, representing either an increase in spicule size/number or a loss of organic material. We also detected rapid decreases in organic content in some months, which corresponded with previously reported reproductive timings for the two species, and likely represent gamete release events. While the increased inorganic content in winter months may be a secondary consequence of reduced food and the sponges having to rely on organic reserves to meet metabolic demand, the higher level of inorganic material in winter likely makes sponges stiffer and stronger, and better able to deal with higher levels of wave action during winter months.

We surveyed the shallow-water sponges of Ascension Island using scuba diving. In total, we collected 58 sponge specimens from 17 locations at depths of 0.5–30 m. In addition, we compiled historical records of sponges. We describe nine species new to science: Niphates verityae sp. nov., Petrosia (Petrosia) ernesti sp. nov., Monanchora downesae sp. nov., Svenzea weberorum sp. nov., Erylus williamsae sp. nov., Ircinia nolanae sp. nov., Ircinia richardsoni sp. nov., Ircinia simae sp. nov. and Chondrosia browningorum sp. nov. We provide molecular sequences for three of the new species. We have added 50% to the number of known species and added two new genera and one family to the known Ascension Island sponge fauna. Twenty-six species, from 16 genera, and 13 families, are now reported from Ascension's shallow waters. Many of these may be endemic to the island. We discuss the biogeographic affinities of Ascension Island and emphasize the need for additional survey of the sponge fauna of remote islands such as Ascension.

The limpet Patella aspera Röding, 1798, is a native species from the Macaronesian region whose fishing is regulated. The early life of limpets, including the settlement process, is poorly known thus far. The current study evaluated different substrates to induce settlement in P. aspera, including microalgae strains (Halamphora coffeaeformis, Navicula incerta and Pavlova sp.) and crustose coralline algae (CCA) obtained from limpet shells. The results showed that gametes obtained by dissection and matured artificially using alkalinized seawater baths can produce viable larvae able to metamorphose to juveniles. Feeding was not required during larval development, suggesting lecithotrophy. Early postlarvae were identified by the shedding of the velum, and juveniles were identified by teleoconch and active grazing behaviour. The presence of CCA shortened the timing for settlement and increased the ratio of juveniles. The type and abundance of CCA can influence settlement success. Moreover, the results suggested that settlement and metamorphosis in true limpets (Patellogastropoda) might be triggered by a two-step mechanism, i.e. a first cue influencing the shift between swimming and crawling activity and a second cue determining settlement and metamorphosis to early postlarvae and juveniles.

Twelve hyper-β carotene-producing strains of algae assigned to the genus Dunaliella salina have been isolated from various hypersaline environments in Israel, South Africa, Namibia and Spain. Intron-sizing of the SSU rDNA and phylogenetic analysis of these isolates were undertaken using four commonly employed markers for genotyping, LSU rDNA, ITS, rbcL and tufA and their application to the study of Dunaliella evaluated. Novel isolates have been identified and phylogenetic analyses have shown the need for clarification on the taxonomy of Dunaliella salina. We propose the division of D. salina into four sub-clades as defined by a robust phylogeny based on the concatenation of four genes. This study further demonstrates the considerable genetic diversity within D. salina and the potential of genetic analyses for aiding in the selection of prospective economically important strains.

Germination of cysts serves as inoculum for the proliferation of some dinoflagellates, and cyst abundance in sediments represents crucial information to understand and possibly predict Harmful Algae Blooms (HABs). Cyst distribution is related to the physical characteristics of the sediments and the hydrodynamics (circulation) of a particular region. In the northern Gulf of California (nGC) several Gymnodinium catenatum HABs have been recorded. However, the presence of resting cysts and the effect of hydrodynamics on their distribution in the nGC have not been investigated. This study evaluated cyst abundance, distribution and their relation to local circulation in surface sediments during two periods that coincided with a non-bloom year condition (July 2016) and after a major HAB registered in the nGC that occurred in January 2017. Also, a numerical ocean model was implemented to characterize the transport and relocation of cysts and sediments in the region. Gymnodinium catenatum cysts were heterogeneously distributed with some areas of high accumulation (as high as 158 cyst g−1, and 27% of total cyst registered). Cysts seemed to be transported in an eastward direction after deposition and accumulated in an extensive area that probably is the seedbed responsible for the initiation of HABs in the region. The nGC is a retention area of cysts (and sediments) that permit the formation of seedbeds that could be important for G. catenatum HAB development. Our results provide key information to understand G. catenatum ecology and specifically, to understand the geographic and temporal appearance of HABs in the nGC.

Phtytoplankton group composition determined by microscopy was compared with high performance liquid chromatography (HPLC) derived from pigment signatures in surface water samples taken bi-weekly and monthly between October 2018 and September 2019 in the Golden Horn Estuary (Sea of Marmara). A total of 80 eukaryotic phytoplankton taxa belonging to eight algal classes were identified in surface water during the study period. Forty-three taxa (54%) were diatoms, 29 taxa (36%) were dinoflagellates and eight taxa (10%) were other phytoflagellates. The average contribution of diatoms to total phytoplankton abundance decreased considerably (41 to 25%), while the average contribution of dinoflagellates and other phytoflagellates increased markedly (59 to 75%) from the lower to the middle estuary. Chlorophyll-a and seven other group-specific pigments, including fucoxanthin, peridinin, chlorophyll-c1 + c2, alloxanthin, 19′-hexanoyloxyfucoxanthin, 19′-butanoyloxyfucoxanthin and divinyl chlorophyll-a were identified in the study area. The relative contribution of the major phytoplankton groups to chlorophyll-a was estimated on three different initial ratio matrices by CHEMTAX. The results obtained were compared with those from microscopic examination. It was concluded that the CHEMTAX method was not accurate enough to characterize the phytoplankton community in the Golden Horn Estuary ecosystem and microscopic analysis was essential to determine the major contributing species to chlorophyll-a.

The availability of colonizable substrate is an important driver of the temporal dynamics of sessile invertebrates on coral reefs. Increased dominance of algae and, in some cases, sponges has been documented on many coral reefs around the world, but how these organisms benefit from non-colonized substrate on the reef is unclear. In this study, we described the temporal dynamics of benthic organisms on an Indonesian coral reef across two time periods between 2006 and 2017 (2006–2008 and 2014–2017), and investigated the effects of colonizable substrate on benthic cover of coral reef organisms at subsequent sampling events. In contrast with other Indonesian reefs where corals have been declining, corals were dominant and stable over time at this location (mean ± SE percentage cover 42.7 ± 1.9%). Percentage cover of turf algae and sponges showed larger interannual variability than corals and crustose coralline algae (CCA) (P < 0.001), indicating that these groups are more dynamic over short temporal scales. Bare substrate was a good predictor of turf cover in the following year (mean effect 0.2, 95% CI: 0–0.4). Algal cover combined with bare space was a good predictor of CCA cover the following year generally, and of sponge cover the following year but only at one of the three sites. These results indicate that turf algae on some Indonesian reefs can rapidly occupy free space when this becomes available, and that other benthic groups are probably not limited by the availability of bare substrate, but may overgrow already fouled substrates.

The gut microbiota plays an important role in animals’ survival in their local environments. The intertidal rocky shore is a key interface of oceanic, atmospheric and terrestrial environments, and the transmission modes of microbes between an intertidal host and the environment are complex and largely ignored. In the present study, we characterized the gut microbiota of the intertidal snail Nerita yoldii, which is experiencing a northward range shift under the combined impacts of climate change and anthropogenic seascape transformation, and also determined the nearby environmental microbiota on the rock and in the seawater at five locations along the snail's distribution range in China. The gut microbial communities were significantly different from the environmental microbial communities, and the dominant phyla were Tenericutes, Cyanobacteria and Bacteroidetes, and Proteobacteria in the gut, rock and seawater microbial communities, respectively. At the genus level, Mycoplasma, with a relative abundance of 48.0 ± 10.2%, was the dominant genus in the gut microbial community, however, the relative abundances of this genus on the rock and in the water were low. These results imply that the gut microbial community of the intertidal snail N. yoldii is relatively independent from the environmental microbial community, and the dominant genus Mycoplasma in the gut, that is rare in the environment, can potentially assist the snail living in the harsh intertidal environment, especially at its northernmost distribution range edge.

Estuaries in Brazil are highly threatened environments and habitat loss is the main influential factor for the increase in the number of strandings of Antillean manatee (Trichechus manatus) calves in the north-eastern region of the country. The aim of the present study was to analyse and quantify the spatiotemporal dynamics of mangroves in the state of Paraíba and the association with manatee calf stranding events. The study area encompassed 10 remaining mangroves along the coast of the state, four of which were located within protected areas. Information on the mangrove forests was obtained from satellite images from the last four decades. Data on stranded Antillean manatee calves were obtained from a databank with records from 1980 to 2019. The data were analysed using geoprocessing techniques and statistical analyses. The results demonstrated changes in the mangrove forest over time, with larger areas existing during the 1980s, reductions in the following periods but a slight increase in the last decade. The number of stranded Antillean manatee calves increased over the years, with stranding events concentrated mainly on the northern coast of the state. The smallest number of stranding events occurred in the 1980s, when the mangrove forests were larger. Our findings confirm that the integrity of mangroves is of extreme importance to the maintenance and sustainability of Antillean manatee populations.

Currently, there is little comparative data on ‘efficiency’ of different engineering species, i.e. species richness, density and biomass of the associated organisms that have been supported by engineering species. The use of fouling communities makes it possible to compare the efficiency of different engineering species under the same conditions, which is necessary to obtain correct estimates and difficult to do when studying natural bottom communities. In this study, we have analysed the fouling communities in four different mussel culture farms in the White Sea to test the following hypotheses. (1) Different engineering species (mussel Mytilus edulis, solitary ascidian Styela rustica, sponge Halichondria panicea) have different assemblages of the associated vagile fauna. (2) Mytilus edulis is the most efficient engineering species, i.e. species richness, species diversity, density and biomass of the associated vagile fauna is higher in the mussel communities than in those dominated by Styela rustica or Halichondria panicea. The first hypothesis was confirmed, while the second was rejected. In all the culture farms studied, all parameters of the mussel-associated vagile fauna were not higher and in most cases were even lower than those of the fauna associated with ascidians or sponges. The reason for this seems to be the very dense packing of mussels in patches. Therefore, Mytilus edulis is not the most efficient engineering species among fouling organisms, at least in the conditions of the subarctic White Sea. The data obtained are particularly important in view of the ever-increasing volume of anthropogenic substrate and fouling communities in coastal marine ecosystems.

Invasive species are leading to ecosystem changes and socioeconomic deterioration around the globe. In 2018, unknown soft corals were noticed forming a massive ‘blue carpet’ on a shallow reef environment at Todos os Santos Bay, South-west Atlantic. In this study we identified the species, quantified their distribution and abundance as a first step for baseline invasion monitoring, and discussed origin, vector and impacts on native competitors. Coral samples were identified based on morphology and a multilocus DNA barcode, and benthic structure was characterized using digital photoquadrats. Our results revealed two new harmful non-native octocorals in this tropical rocky reef, the ‘blue polyps’ genus Sarcothelia (Xeniidae), native to Hawaii but likely an undescribed cryptic species, and Briareum hamrum (Briareidae), native to the Indian Ocean. Sarcothelia sp. was the dominant taxon in the rocky reef (mean cover 23.66% ± 21.46), exhibiting high coverage as well in the sandy and patch reef habitats (15.83% ± 15.81), however, only three colonies of B. hamrum were found, all outside the sampling area. These octocorals were in physical contact with native benthic organisms, mainly with the most abundant group, but apparently avoid turf algae in sandy and patch reef habitats. We suggest that irresponsible marine aquarium releases likely introduced these species to Brazilian reefs. After identifying the aquarium trade as the main vector of octocoral introductions, we reinforce the importance of inspecting marine species importation and the urgent need to implement a government plan to mitigate invasive species' impacts on the natural reefs of Brazil.

In Saroma-ko Lagoon, where scallop aquaculture is a thriving commercial activity, monitoring primary production is essential for determining the amount of scallops that can be farmed. Using the primary production data obtained so far, we calculated Ψ, an index of water-column light utilization efficiency, and clarified its seasonal variation. Ψ tended to be lower in the spring bloom season (February–April), and higher in the late autumn to winter (October–December). Low chlorophyll-normalized production, an index of growth rate, resulted in lower values, while low daily irradiance resulted in higher values. The values of Ψ from our study had a range of 0.05–1.42 gC gChl-a−1 mol photons−1 m2 (N = 56). These values were within the previously reported range of 0.07–1.92 (gC gChl-a−1 mol photons−1 m2) for seawater and fresh water worldwide. Therefore, it is likely that Ψ varies from 0.05–2 gC gChl-a−1 mol photons−1 m2, being affected by conditions of phytoplankton growth and sunlight intensity, regardless of whether samples are collected from seawater or fresh water. Using the median Ψ value of 0.45 gC gChl-a−1 mol photons−1 m2 obtained in this study, primary production was 0.3–3.5 times the actual production at Saroma-ko Lagoon. Using this method, primary production can be easily and constantly monitored, facilitating the sustainable development of scallop aquaculture.

The ocean quahog, Arctica islandica, is a commercially important bivalve in the eastern USA but very little is known about the recruitment frequency and rebuilding capacity of this species. As the longest-living bivalve on Earth, A. islandica can achieve lifespans in excess of 200 y; however, age determinations are difficult to estimate and age variability at size is extreme. Objectives for this study included the creation of an extremely large age-composition dataset to constrain age at length variability, development of reliable age-length keys (ALK), and descriptions of sex-based population dynamics for the quasi-virgin A. islandica population at Georges Bank (GB) within the greater US Mid-Atlantic stock. Sexually dimorphic characteristics are clearly present, as females are larger than males within age classes and males tend to dominate the oldest age classes. A male represented the maximum age of 261 years and is older than the maximum age previously documented for this region. Sex-specific ALKs were robust and reliable but not interchangeable. This population had higher estimated natural mortality rates than presumed for other regions in the Mid-Atlantic, and females have the highest mortality rate. However, recruitment expansion was also occurring which would affect the age-frequency data used to derive mortality estimates and result in higher mortality. Age frequencies at GB suggest effective recruitment to the population each year since 1867 CE. Reduced recruitment periods are documented and likely attributed to fluctuating environmental conditions. Sex-based demographics are clearly divergent in regard to growth rate, maximum size, longevity and mortality rates.