Marine Biology最新文献

A comprehensive survey of the octopus fauna around the Americas is presented to facilitate and accelerate the assessment of a full understanding of American octopus biodiversity. Brief accounts are provided summarizing research efforts on octopus species taxonomy, diversity and distribution in different regions of North and South America. Octopus americanus and O. insularis are compared and clearly distinguished from each other and from the closely-related European species, O. vulgaris. The use of genus names Paroctopus and Pinnoctopus is clarified. Included is a discussion of the recent application of genus name Paroctopus to warm-temperate and tropical species of small size, along with a cautionary note about species identifications in the light of past errors in misassigning large-to-giant cold-water species to genus Paroctopus. Related to problems with identifying species of Paroctopus, there is an appended note concerning misidentifications and the importance of thorough species descriptions to obtain species information at the levels of both phenotype and genotype. A lectotype is formally designated for Bathypolypus arcticus (Prosch, 1849); and the status of so-called ‘Octopus giganteus’ is reviewed briefly. A supplementary online database, AmeriCeph, provides basic information about all known octopus species of the Americas, including the institutional location of type material and the identification of voucher specimens and their depositories. DNA sequences registered in this database are not all fully compatible with barcoding standards. However, a subset of DNA sequences conforming to strict barcode identifications is provided in a second supplementary table, providing barcode sequences directly applicable also to improving standards of seafood traceability. This in turn contributes to building sustainability of exploited octopus fisheries stocks and identification of species suitable for aquaculture trials to meet the increasing commercial demand for octopus worldwide.

Offshore windfarms are a potential threat to seabirds, partly due to collision risk with turbine blades. Wind influences the mode, height and speed of seabird flight, and therefore the risk of collision with turbines. We investigated how wind influences the flight of black-legged kittiwakes Rissa tridactyla, a gull of conservation concern, in order to incorporate these findings into collision risk estimates and identify mitigation measures. We used GPS telemetry data (23rd June to 10th August 2021) from 20 kittiwakes breeding in Aberdeenshire, UK (57.385°N, 1.868°W) to estimate the effect of wind on behavioural state, proportion of flight at collision risk height, probability of collision when within the rotor-swept zone, and overall collision risk. We found that as windspeed increased, kittiwakes commuted less and rested more. With increasing windspeed, kittiwakes spent a considerably smaller proportion of their flight time in the rotor-swept zone, but had a slightly higher probability of collision while in it. Uncertainty was high for most relationships between windspeed and kittiwake flight metrics. The overall effect of increasing windspeed on collision risk was negative, although we did not model avoidance rate. Effects of windspeed on collision risk were largely mediated through effects on commuting flight, and contingent on wind direction. Collision risk estimates incorporating the effects of windspeed may have greater precision and accuracy, but considerable uncertainty in windspeed-flight parameter relationships remains. Therefore although kittiwake collision risk may be mitigated by raising the ‘cut-in’ windspeed above which wind turbines generate power, the magnitude of this effect is uncertain.

Seabirds are among the most threatened avian taxa. Effective seabird conservation requires an understanding of both seabird distributions and habitat usage. Species distribution models can help identify important areas for protection and manage threats to seabird populations. However, populations of the same species may differ in their response to the environment, reducing the transferability of such models. In addition, individual-level responses to habitat may vary both within and between animal populations. Atlantic Puffins (Fratercula arctica) are classed as vulnerable to global extinction and a UK red-listed bird of concern. Consequently, a greater understanding of their at-sea habitat usage is a conservation priority. We used GPS tracking data from four UK Puffin colonies to construct species distribution models and examine colony- and individual-level variation in habitat usage in response to a suite of environmental covariates (chlorophyll-a concentration, sea surface temperature (SST), water depth, seabed slope, current velocity, and SST front gradient). The most consistent colony-level response was a negative association between habitat usage and chlorophyll-a concentration (observed at 3 out of 4 colonies). Responses to other environmental covariates were less consistent across colonies. Among individual variation in foraging range per trip was low, but we observed individual variation in habitat usage in response to almost all environmental covariates examined. Within each colony, we also identified distinct clusters of space-use across different groups of individuals. Different Puffin colonies and individuals are not ecologically equivalent. Therefore, perturbations to the marine environment are likely to have disproportionate effects on certain colonies and/or individuals. Incorporating colony- and individual-level variation will thus be essential for marine conservation efforts.

Coral calcification is critical for reef growth and highly dependent on environmental conditions. Yet, little is known about how corals calcify under sub-optimal conditions (e.g., turbid waters, high nutrients, sedimentation) or coral growth in understudied regions such as the Colombian Caribbean. We therefore assessed the calcification and linear extension rates of five coral species across an inshore-to-offshore gradient in the Colombian Caribbean. A suite of environmental variables (temperature, light intensity, visibility, pH, nutrients) measured during the rainy season (May – November 2022) demonstrated more sub-optimal conditions inshore compared to offshore. Across all species, calcification rates were 59% and 37% lower inshore compared to the offshore and midshore sites, respectively. Across all sites, massive corals calcified up to 92% more than branching species but were more susceptible to heat stress and sub-optimal inshore conditions. However, branching species had reduced survival due to extreme climatic events (i.e., bleaching, hurricanes). A comparison with published rates for the wider Caribbean revealed that massive species in the Colombian Caribbean grow up to 11 times more than those in the wider Caribbean while branching species generally have similar growth rates, but this finding may have been influenced by fragment size and/or heat stress. Our findings indicate that present-day environmental conditions, coupled with more frequent extreme climatic events, will favor massive over branching species in midshore areas of the Colombian Caribbean. This suggests a possible shift towards faster calcifying massive species in future coral communities, possibly exacerbating the ongoing regional decline in branching species over the last decades.

This study examines the importance of both macroalgal heterogeneity and specific macroalgal species or morphotypes to nursery provision for juvenile sparids (Diplodus capensis and Sarpa salpa) in a shallow (< 2 m), sheltered rocky cove in warm-temperate Algoa Bay, South Africa. The rocky cove is comprised of a mosaic of two main benthic habitats; canopy-forming Plocamium corallorhiza beds on rocky outcrops and flat reef dominated by low growing red algae morphotypes. We assessed macroalgal communities and the trophic ecology (stomach contents and isotopes), abundance and size structure of D. capensis and S. salpa in the two different benthic habitats and the resources/food associated with the dominant macroalgae species/morphotypes. We found high densities of S. salpa and D. capensis, in both high profile reef (rocky outcrops) and low profile (flat) reef. Within this habitat mosaic resources (epiphytes and macroinvertebrates) were more abundant in the non-canopy forming low growing macroalgae (Laurencia spp. and coralline turf algae) and these algae were also assimilated in the diets of both sparids. The high abundance of both juvenile S. salpa and D. capensis in high profile and low profile reef, suggests that within this mosaic of habitats these species may be using canopy-forming algae in the high profile reef for shelter and non-canopy forming algae in both the high and low profile reef for food. This shows that macroalgal habitats comprising several morphotypes have the potential to support higher juvenile diversity and abundance through both food provision and shelter.

Vayssierea is an understudied nudibranch genus characterized by its orange colouration and small size (up to 5 mm in length). To date, there are four described species, distributed in the Indo-Pacific Ocean. Here, individuals of Vayssierea were recorded for the first time in the North Atlantic Ocean on the Canary Islands (Spain). This study aims to evaluate the systematic and taxonomic status and distribution of the genus through multilocus phylogenetic, morphological, and radular analyses. Phylogenetic results show the monophyly of Vayssierea and evidence indicating that the genus is included in the new subfamily Okadaiinae stat. nov. within Polyceridae. According to species delimitation tests, four different species have been sequenced from Russia to Australia, in addition to our new records in the Atlantic Ocean, but more information is needed to identify the species. Nevertheless, our specimens from the Canary Islands belong to two different species, one of which is identical to the Australian species. Bearing in mind that they lack a planktonic larval stage; we hypothesize that they arrived by shipping transportation or aquarium releases, becoming a non-indigenous species of the Atlantic Ocean.

Food webs in ecotones linking adjacent ecosystems may depend on cross-ecosystem subsidies. In surf zones of temperate sandy beaches, higher-level consumers often rely on intertidal prey that utilize allochthonous primary production. We evaluated the importance of phytoplankton and kelp-based prey, as well as physical characteristics of beaches, to diet of a surf zone fish, barred surfperch (Amphistichus argenteus), through stomach content and stable isotope analyses. Our results suggested that barred surfperch rely on prey from both phytoplankton and kelp-based subsidies, but their relative contribution to diet varied widely across beaches. Sand crabs (Emerita analoga), which depend on phytoplankton, were abundant at every beach, but their contribution to diet in stomach contents varied from 2 to 87% among sites. At the majority of beaches, δ¹³C values of fish muscle tissue, which reflects diet integrated over time, were within 0.5 ‰ of sand crab values, suggesting a reliance on phytoplankton-based prey. However, kelp-dependent prey associated either with beach wrack or subtidal reefs was also present in surfperch stomachs from all beaches (up to 41–72%). The notable enrichment in ¹³C of juvenile surfperch at two beaches and adults at one beach relative to sand crabs suggested a longer-term contribution of kelp-based prey to fish diet. The detection of kelp-based prey in surfperch diets also indicates the potential for reciprocal subsidies in these ecotones. Our results suggest trophic connectivity between surf zones and kelp forests and sandy beaches is spatially variable and that opportunistic higher-level consumers can shift their diet in response to the availability of phytoplankton and kelp-based food resources.

The impacts of (repeat) bleaching events and the differential heat stress susceptibility of hard coral taxa are largely unknown in Malaysia, although it is part of the greater coral triangle. Here we determined bleaching trajectories of 46 hard coral taxa across- and within-reef scales based on data recorded during the first reported back-to-back coral bleaching occurrences in Malaysia between May 2019 and September 2020. Although the severity of coral bleaching in both years did not correspond to the rather small magnitude of heat stress observed, i.e., Degree Heating Weeks (DHW) of 1.05 °C-weeks and 0 °C-weeks in 2019 and 2020 respectively, we observed high levels of bleaching (55.21% and 26.63% of all surveyed colonies in 2019 and 2020, respectively). Notably, the bleaching response for both consecutive years was highly taxon-specific and significantly varied across- and within-reef scales. Mortality rates overall were low following the 2019 event, likely due to a rapid decrease in heat stress. Five of the 46 surveyed hard coral taxa exhibited more severe bleaching in 2020, despite a lower heat stress load. Interestingly, we observed low bleaching of ascribed susceptible taxa such as Acropora and Montipora, while we found taxa considered to be resilient, e.g. Heliopora and Porites, to exhibit severe bleaching, suggesting a reversal of bleaching hierarchies of taxa over time. Our findings provide a foundation for further coral bleaching studies in a region with few published records to enable more accurate regional assessments and to follow the trajectory of future coral bleaching events.

Biological data collection often overlooks short-term environmental variations, potentially leading to under- or over-estimation of species abundance and ineffective conservation actions. This study investigated the complex relationship between oceanic and meteorological processes and the short-term abundance patterns of two economically important fish species in Bahía Santa Elena, a tropical bay on the north Pacific coast of Costa Rica. Using two months of continuous acoustic telemetry data from 14 Colorado (Lutjanus colorado) and 16 Pacific dog (Lutjanus novemfasciatus) snappers, we investigated temporal and spatial changes in their relative abundance patterns. A wavelet analysis revealed dominant diurnal and semidiurnal frequencies in both species. The observed semi-diurnal and diurnal periodicity in fish abundance was correlated with water level and sunlight, particularly near the mangrove in the inner bay, suggesting that both species may be using these habitats for food and shelter during periods of high tide and at night. Understanding how oceanic and meteorological conditions influence the dynamics of marine organisms in coastal environments, particularly those that are often exploited by fisheries is crucial for developing effective management and conservation approaches.

Guanosine Triphosphate (GTP)ases of Immunity Associated Proteins (GIMAP) are small G proteins that in vertebrates, regulate immunity, apoptosis, and autophagy. While previously thought to be limited to vertebrates and plants, this family of proteins was recently characterized in a diversity of dinoflagellates. However, information regarding the function of GIMAPs in dinoflagellates is lacking. Therefore, the goal of this study (conducted from March-November of 2022) was to assess the expression of GIMAPs in the cnidarian symbiont Breviolum minutum (formerly Symbiodinium minutum, referred to as Bm_GIMAPs) in response to low light (25 vs 8 μmol m⁻² s⁻¹ for 9 d), thermal stress (22 vs 28 °C for 48 h), and symbiotic state (cultured vs in hospite). These factors were selected due to their importance in the lifestyle of a photosynthetic symbiont and relevance to the ecologically important issue of coral bleaching. The results indicate Bm_GIMAP expression increased under both low light and elevated temperature, suggesting a role in the response to bleaching related stressors. Cultured B. minutum had lower baseline Bm_GIMAP expression than those in association with a cnidarian host, but a stronger response to thermal stress, suggesting their function is influenced by symbiosis. Lastly, further support for the responsiveness of GIMAPs to thermal stress was provided by a comparison with previously published RNA-seq data from cultured Symbiodiniaceae. Collectively, the results presented here represent the first functional investigation of GIMAPs in an ecologically important group of protists and provide a greater understanding of the molecular response of dinoflagellates to stressors related to bleaching.