Marine Invertebrate Species Research Articles

Evaluating the Potential of Marine Invertebrate and Insect Protein Hydrolysates to Reduce Fetal Bovine Serum in Cell Culture Media for Cultivated Fish Production.

The use of fetal bovine serum (FBS) and the price of cell culture media are the key constraints for developing serum-free cost-effective media. This study aims to replace or reduce the typical 10% serum application in fish cell culture media by applying protein hydrolysates from insects and marine invertebrate species for the growth of Zebrafish embryonic stem cells (ESC) as the model organism. Protein hydrolysates were produced from black soldier flies (BSF), crickets, oysters, mussels, and lugworms with a high protein content, suitable functional properties, and adequate amino-acid composition, with the degree of hydrolysis from 18.24 to 33.52%. Protein hydrolysates at low concentrations from 0.001 to 0.1 mg/mL in combination with 1 and 2.5% serums significantly increased cell growth compared to the control groups (5 and 10% serums) (p < 0.05). All protein hydrolysates with concentrations of 1 and 10 mg/mL were found to be toxic to cells and significantly reduced cell growth and performance (p < 0.05). However, except for crickets, all the hydrolysates were able to restore or significantly increase cell growth and viability with 50% less serum at concentrations of 0.001, 0.01, and 0.1 mg/mL. Although cell growth was enhanced at lower concentrations of protein hydrolysates, the cell morphology was altered due to the lack of serum. The lactate dehydrogenase (LDH) activity results indicated that BSF and lugworm hydrolysates did not alter the cell membrane. In addition, light and fluorescence imaging revealed that the cell morphological features were comparable to those of the 10% serum control group. Overall, lugworm and BSF hydrolysates reduced the serum by up to 90% while preserving excellent cell health.

Species and genetic diversity relationships in benthic macroinvertebrate communities along a salinity gradient

BackgroundSpecies- and genetic diversity can change in parallel, resulting in a species-genetic diversity correlation (SGDC) and raising the question if the same drivers influence both biological levels of diversity. The SGDC can be either positive or negative, depending on whether the species diversity and the genetic diversity of the measured species respond in the same or opposite way to drivers. Using a traditional species diversity approach together with ultra-conserved elements and high throughput sequencing, we evaluated the SGDCs in benthic macrofauna communities in the Baltic Sea, a geologically young brackish water sea characterised by its steep salinity gradient and low species richness. Assessing SGDCs from six focal marine invertebrate species from different taxonomic groups and with differing life histories and ecological functions on both a spatial and temporal scale gives a more comprehensive insight into the community dynamics of this young ecosystem and the extrinsic factors that might drive the SGDCs.ResultsNo significant correlations between species diversity and genetic diversity were found for any of the focal species. However, both negative and positive trends of SGDCs for the individual focal species were observed. When examining the environmental drivers, no common trends between the species were found, even when restricting the analysis to specific taxonomic classes. Additionally, there were no common environmental factors driving the diversity relationships for species sharing the same SGDC trend (positive or negative). Local population dynamics, together with the invasion history of the individual species and their unique adaptation to the distinctive environment of the Baltic Sea, are expected to be of major influence on the outcome of the SGDCs.ConclusionsThe present results highlight the importance of assessing SGDCs using multiple species, not just a single indicator species. This emphasises a need to pay attention to the ecology and life history of the focal species. This study also provides insight into the large differences in both patterns and drivers of genetic diversity, which is important when including genetic biodiversity in conservation plans. We conclude that the effects of environmental and biological factors and processes that affects diversity patterns at both the community and genetic levels are likely species dependent, even in an environment such as the Baltic Sea with strong environmental gradients.

The environmental remediation capacity of Ulva lactuca: the potential of macroalgae to reduce the threats caused by Titanium in marine invertebrate species

As a result of the wide use of Titanium (Ti) compounds in various products, Ti and Ti nanoparticles (nTi) are released into aquatic environments, inducing varying degrees of toxicity on aquatic fauna. Ulva lactuca, green macroalgae commonly found in coastal areas, has been extensively studied due to its worldwide distribution and capacity to accumulate trace elements under toxic conditions, which makes it a good universal sorbent. The present study aimed to establish the remediation properties of U. lactuca by evaluating the toxicity of Ti and nTi in bivalves, in the presence and absence of algae. Using the bivalve species Mytilus galloprovincialis, Ti toxicity was evaluated by assessing changes in mussel's metabolic capacity and oxidative status. Results evidenced cellular damage in M. galloprovincialis exposed to Ti and nTi. This was a result of the inactivation of antioxidant defences. The presence of U. lactuca limited cellular damage, however, this was not a result of the previously demonstrated bioremediation capacity, as no accumulation of Ti was verified in algal tissues. As a metabolic depression was verified for mussels exposed to Ti/nTi in the presence of algae, we hypothesise that U. lactuca may have been responsible for changes to the water quality which induced this response.

Macroevolutionary patterns in marine hermaphroditism.

Most plants and many animals are hermaphroditic; whether the same forces are responsible for hermaphroditism in both groups is unclear. The well-established drivers of hermaphroditism in plants (e.g., seed dispersal potential, pollination mode) have analogues in animals (e.g., larval dispersal potential, fertilization mode), allowing us to test the generality of the proposed drivers of hermaphroditism across both groups. Here, we test these theories for 1153 species of marine invertebrates, from three phyla. Species with either internal fertilization, restricted offspring dispersal, or small body sizes are more likely to be hermaphroditic than species that are external fertilizers, planktonic developers, or larger. Plants and animals show different biogeographical patterns, however: animals are less likely to be hermaphroditic at higher latitudes-the opposite to the trend in plants. Overall, our results suggest that similar forces, namely, competition among offspring or gametes, shape the evolution of hermaphroditism across plants and three invertebrate phyla.

Combined biophysical and genetic modelling approaches reveal new insights into population connectivity of New Zealand green-lipped mussels

Understanding how ocean currents affect larval transport is crucial for understanding population connectivity in sessile marine invertebrates whose primary dispersal opportunity occurs during the pelagic larval stage. This study used Lagrangian particle tracking experiments to examine population connectivity in New Zealand green-lipped mussels (Perna canaliculus) at the national scale. Predicted patterns of larval dispersal were compared to published multi-locus microsatellite data of observed population genetic structure. Estimates of oceanographic circulation correlated significantly with FST, and we conclude that hydrodynamic processes are important in driving genetic connectivity. However, no evidence was found for an oceanographic barrier to gene flow south of Cook Strait, an important feature of genetic structure observed across several marine invertebrate species. Discrepancies between genetic and biophysical data may be explained by several factors including the different timescales of connectivity described by the two methods and the impact of localised ecological conditions and corresponding adaptations in genetic structure not captured by the bipohysical model. Population genetic analyses provide empirical data on realised connectivity and Lagrangian particle tracking experiments reveal information about directionality and asymmetry of connections that often cannot be determined by molecular analyses alone, thus a multidisciplinary approach is recommended.

Caspase-1 and Cathepsin B Inhibitors from Marine Invertebrates, Aiming at a Reduction in Neuroinflammation.

Neuroinflammation is a condition associated with several types of dementia, such as Alzheimer’s disease (AD), mainly caused by an inflammatory response to amyloid peptides that induce microglial activation, with subsequent cytokine release. Neuronal caspase-1 from inflammasome and cathepsin B are key enzymes mediating neuroinflammation in AD, therefore, revealing new molecules to modulate these enzymes may be an interesting approach to treat neurodegenerative diseases. In this study, we searched for new caspase-1 and cathepsin B inhibitors from five species of Brazilian marine invertebrates (four cnidarians and one echinoderm). The results show that the extract of the box jellyfish Chiropsalmus quadrumanus inhibits caspase-1. This extract was fractionated, and the products monitored for their inhibitory activity, until the obtention of a pure molecule, which was identified as trigonelline by mass spectrometry. Moreover, four extracts inhibit cathepsin B, and Exaiptasia diaphana was selected for subsequent fractionation and characterization, resulting in the identification of betaine as being responsible for the inhibitory action. Both molecules are already found in marine organisms, however, this is the first study showing a potent inhibitory effect on caspase-1 and cathepsin B activities. Therefore, these new prototypes can be considered for the enzyme inhibition and subsequent control of the neuroinflammation.

Local-scale thermal history influences metabolic response of marine invertebrates to warming

As climate change continues, anticipating species’ responses to rising temperatures requires an understanding of the drivers of thermal sensitivity, which itself may vary over space and time. We measured metabolic rates of three representative marine invertebrate species (hermit crabs Pagurus hirsutiusculus, periwinkle snails Littorina sitkana, and mussels Mytilus trossulus) and evaluated the relationship between thermal sensitivity (Q10) and thermal history. We tested the hypothesis that thermal history drives thermal sensitivity and quantified how this relationship differs over time (short-term to seasonal time scales) and between species. Organisms were collected from tide pools in Sitka, Alaska where we also recorded temperatures to characterize thermal history prior to metabolic rate assays. Using respirometry, we estimated mass-specific oxygen consumption (MO2) at ambient and increased temperatures for one individual per species per tide pool across three seasons. We evaluated relationships between thermal sensitivity and pool temperatures for time periods ranging from 1 day to 1 month prior to collection. For all species, thermal sensitivity was related to thermal history for the shorter time periods (1 day to 1 week). However, the direction of the relationships and most important thermal parameters (i.e., maximum, mean, or range) differed between species and seasons. We found that on average, P. hirsutiusculus and L. sitkana were more thermally sensitive than M. trossulus. These findings show that variability in thermal history over small spatial scales influences individuals’ metabolic response to warming and may be indicative of these species’ ability to acclimate to future climate change.

Wild-caught fish populations targeted by MSC-certified fisheries have higher relative abundance than non-MSC populations

Requirements for a fishery to achieve Marine Stewardship Council (MSC) certification include demonstrating that targeted populations (‘MSC stocks’) are fished at sustainable levels. The credibility of this claim can be evaluated by comparing estimated abundance of MSC stocks to benchmarks based on sustainability criteria. Additionally, to evaluate whether MSC certification provides a meaningful distinction, the sustainability status of MSC stocks can be compared with that of populations without a linked certificate (‘non-MSC stocks’). It is expected that MSC stocks are more likely to be maintained at levels of high abundance relative to sustainability benchmarks compared to non-MSC stocks. Similarly, it is expected that MSC stocks are less likely to become overfished, and if they do become overfished, that fisheries are incentivised to aid in their rebuilding to avoid suspension of certification. We compare published biomass estimates relative to biological reference points between MSC stocks and non-MSC stocks of wild-caught marine fish and invertebrate species around the world. These are observational data, and though we control for the propensity of certification, certification is not independent of relative biomass and therefore we describe associations rather than causal influences. Individual stocks from both groups were highly variable in relative biomass trends over the past two decades, with substantial overlap in the distributions of MSC and non-MSC stocks. In recent years (2014-2018), MSC stocks had, on average, greater biomass relative to biomass at maximum sustainable yield (BMSY) than non-MSC stocks. MSC stocks were also less frequently overfished compared to non-MSC stocks, with estimated biomass below a limit reference point (Blim) for 9% of MSC stocks and for 26-33% of non-MSC stocks. Eight MSC stocks currently or previously certified and defined as overfished in 2017 or 2018 had previously entered the program based on scientific advice available at the time indicating they were fished within sustainable limits. Subsequently, when revised stock assessments estimated the biomass to be lower than previously thought, fisheries for those stocks were suspended from certification. Together, these results suggest that eco-certification is associated with a credible claim on sustainable stock status and provides a useful distinction from other seafood. Further, our results show how the rare exceptions to this pattern may arise from retrospective changes in scientific advice.

Annotated checklist and genetic data for parasitic helminths infecting New Zealand marine invertebrates

AbstractParasitic helminths with complex life cycles require multiple hosts in a particular order to complete their life cycles. Although almost all helminths infect invertebrates at some point in their life cycle, we know very little about which species of invertebrates harbor parasites compared with what is known for vertebrates. In New Zealand, &lt;1% of marine invertebrates that may be expected to host parasites have records of parasite infections. This is a strong indication that our knowledge of invertebrate parasites within marine ecosystems is highly limited. Here, we provide the first comprehensive parasite–host checklist including data from the literature and newly discovered infections of parasitic helminths infecting marine invertebrates in New Zealand. Including both pre‐existing and newly found data from our survey, we present data on 73 parasite taxa (five acanthocephalans, 13 cestodes, nine nematodes, and 46 trematodes) infecting 62 marine invertebrate species in New Zealand. In addition, we compile existing and new genetic data for many of these parasites, as a useful tool for future studies of parasite biodiversity and phylogenetics.

Detection and monitoring of invertebrate non-indigenous species through DNA metabarcoding in a recreational marina of the Northwest of Portugal

In marine and coastal ecosystems, the proliferation of non-indigenous species (NIS) is among the top causes of biodiversity loss. Thus, it is essential to prevent the entrance and proliferation of NIS by detecting their presence as early as possible at the most susceptible locations, such as ports and marinas. Molecular techniques, like DNA metabarcoding, may be faster and more effective in the early detection of NIS. Its high sensitivity allows the detection of species at any stage of their life cycle and when present at very low densities. However, the detection power can be affected by the methodologies employed through the DNA metabarcoding analytical chain. This study aimed to assess the seasonal effects, sampling method (hard and artificial substrates, zooplankton and eDNA) and genetic marker (COI and 18S) in the recovery of NIS through DNA metabarcoding. Sampling was conducted in 3 seasons (spring, autumn, and winter of 2020/2021) in the “Porto Atlântico” marina, which is located near a major commercial port of the North of Portugal (Leixões). Overall, 626 species were identified through DNA metabarcoding, with the dominance of Crustacea, Ascidiacea and Mollusca. The sampling method and season significantly affected the marine invertebrate species recorded, for both molecular markers, with a high proportion of species detected exclusively using one method (7 to 20%). Overall, 31 NIS were detected, 7 of which are considered invasive and 6 are presumed new records in mainland Portugal. Zooplankton sampling and winter were, respectively, the method and the season where the highest number of NIS was detected, but the maximum number was only attained when pooling the results from all sampling methods and seasons. Our study highlights that different sampling methods and genetic markers, over different seasons, are needed to detect NIS in marine habitats, since the number of species shared by these factors is low.

Capacity for Cellular Osmoregulation Defines Critical Salinity of Marine Invertebrates at Low Salinity

Low-salinity stress can severely affect the fitness of marine organisms. As desalination has been predicted for many coastal areas with ongoing climate change, it is crucial to gain more insight in mechanisms that constrain salinity acclimation ability. Low-salinity induced depletion of the organic osmolyte pool has been suggested to set a critical boundary in osmoconforming marine invertebrates. Whether inorganic ions also play a persistent role during low-salinity acclimation processes is currently inconclusive. We investigated the salinity tolerance of six marine invertebrate species following a four-week acclimation period around their low-salinity tolerance threshold. To obtain complete osmolyte budgets, we quantified organic and inorganic osmolytes and determined fitness proxies. Our experiments corroborated the importance of the organic osmolyte pool during low-salinity acclimation. Methylamines constituted a large portion of the organic osmolyte pool in molluscs, whereas echinoderms exclusively utilized free amino acids. Inorganic osmolytes were involved in long-term cellular osmoregulation in most species, thus are not just modulated with acute salinity stress. The organic osmolyte pool was not depleted at low salinities, whilst fitness was severely impacted. Instead, organic and inorganic osmolytes often stabilized at low-salinity. These findings suggest that low-salinity acclimation capacity cannot be simply predicted from organic osmolyte pool size. Rather, multiple parameters (i.e. osmolyte pools, net growth, water content and survival) are necessary to establish critical salinity ranges. However, a quantitative knowledge of cellular osmolyte systems is key to understand the evolution of euryhalinity and to characterize targets of selection during rapid adaptation to ongoing desalination.

Comparative phylogeography in a marine biodiversity hotspot provides novel insights into evolutionary processes across the Atlantic‐Indian Ocean transition

AbstractAimIntraspecific genetic variation is a key component of biodiversity, with higher diversity indicating greater resilience and population substructuring suggesting unique evolutionary histories. Comparative approaches, in which intraspecific genetic variation is assessed across multiple species, are powerful tools to identify evolutionary hotspots, but are still rarely applied at spatial scales relevant to conservation planning. Here, we use comparative phylogeography to understand patterns and potential drivers of genetic variation within a biodiversity and ocean warming hotspot.LocationThe South African coastline, Indian/Atlantic Oceans.MethodsA literature search was conducted to obtain mitochondrial DNA cytochrome oxidasecsubunit I and cytochromebsequence data for 17 marine fish and invertebrate species. From these data, we compared averages of haplotype and nucleotide diversity, and within‐region ΦSTbetween four biogeographic provinces in the region. Mixed linear models tested whether environmental variability, habitat preference, or geographic location significantly influence genetic variation.ResultsAverage diversity values differed between haplotype and nucleotide diversity, but both broadly displayed highest diversity levels within the South‐West bioregion, which is also a region of high levels of within‐region ΦST. Range in sea surface temperatures (SSTs) was the only significant fixed‐effect term in the haplotype diversity mixed linear models. Mean SST, stability in SSTs since the Mid‐Holocene and position within the species' geographic distribution all had no significant effect on genetic variation.Main conclusionsAlong this coastline characterized by high environmental heterogeneity, we find that variation in temperature is a prominent source of intraspecific variation. Genetic diversity differs between bioregions, but does not display higher levels within the core of each species’ range when assessed across multiple species. With elevated levels of genetic diversity, the South‐West region of the South African coast is highlighted as a conservation priority area, representing both high genetic diversity and differentiation across taxa.

Does larval food availability ultimately select for seasonal reproduction in marine invertebrates with feeding larvae? A field test of Crisp’s Rule with the temperate sea star Pisaster ochraceus

AbstractMost organisms reproduce seasonally, including most species of marine invertebrates that live across wide ranges in habitat, depth and environmental conditions. We asked: What ultimately selects for seasonal reproduction in benthic marine invertebrates with planktotrophic larvae (characteristic of ≥70% of marine invertebrates)? We hypothesized that seasonal variation in food available for the larvae ultimately selects for timing of adult reproduction. Testing this hypothesis requires a whole life cycle perspective and approach. Using a known proximate cue, daylength, we shifted gametogenesis in the laboratory by six months in a seasonally breeding temperate sea star, the Ochre Star Pisaster ochraceus (Brandt 1835). We were then able to induce spawning, fertilize gametes and culture resulting embryos in vitro to produce feeding larvae six months out of phase with natural photoperiod. We field‐reared these out‐of‐season larvae, similarly produced in‐season conspecifics and similar larvae of an aseasonally breeding asteroid, the Bat Star Patiria miniata (Brandt 1835) in mesh‐covered flow‐through containers that were deployed in seasonally contrasting oceanographic conditions reflecting different productivity regimes and larval food availability in spring and fall. Larval development and survival were similar between seasons: for example, planktonic larval duration was 48 d to first metamorphosis in spring vs. 45 d in fall for P. ochraceus. Hence, temporal variation in available phytoplankton may not be an ultimate selection factor acting on these larvae to regulate timing of seasonal reproduction in the adults. Alternatively, in this and other species of marine invertebrates, selection acting on early benthic juveniles or other life stages may determine the timing of adult reproduction.

The effects of prostaglandin E2 on gonadal development and germ cell proliferation, and its presence during the gonadal cycle in the sea cucumber, Holothuria scabra

Prostaglandin E2 (PGE2) plays important roles in several physiological processes, including reproduction of several marine invertebrate species. The aims of the present study were to characterize the putative prostaglandin E synthase (PGES), an enzyme that is involved in the PGE2 biosynthetic pathway, in the sea cucumber, H. scabra. We then examined the presence and distribution of PGES and PGE2 in gonadal tissues using RT-qPCR and immunohistochemistry, and further investigated the effects of PGE2 on gonadal development and germ cell proliferation by using functional assays. Transcriptomic data and molecular cloning analyses from gonadal tissues of H. scabra were performed, and these tissues were found to have the PGES in H. scabra, namely Hs-cPGES3. By using RT-qPCR, the Hs-cPGES3 mRNA expression levels were higher at the early stages than the late stages of the gonadal cycle. In addition, the presence of PGE2 and its corresponding enzyme, Hs-cPGES3, was detected in the gonads with the highest intensities appearing in gamete cytoplasm during the early stages than those at the late stages. Functionally, PGE2, at the doses of 50 and 500 ng/g BW, significantly promoted gonadal development, gonado-somatic index (GSI), gonadal tube diameters, and increased germ cell proliferation, compared with those of the control animals (P < 0.05). Taken together, our findings are the first to demonstrate the presence of PGE2 and its biosynthetic-associated enzymes in the gonadal tissues, and its effects on gonadal development and germ cell proliferation in this sea cucumber. The knowledge gained would improve understanding of PGE2 mechanism in controlling gonadal development, which could be useful in enhancing the production of seeds for aquaculture of H. scabra.

Daño ambiental en el litoral marino peruano causado por el derrame de petróleo (enero 2022) en la refinería La Pampilla

An environmental disaster of incalculable dimensions was caused by the oil spill that occurred on Saturday, January 15, 2022, when the unloading pipeline of the Italian tanker Mare Dorium ruptured during its loading and unloading activities in the marine littoral of La Pampilla Refinery. The objective of the study was to make a first approximation of the environmental damage produced 30 days after the oil spill at the La Pampilla Refinery. It has been elaborated based on documentary analysis, information from documents of public agencies and scientific articles from indexed bases. The oil spill has spilled 11,900 barrels that have moved in a northerly direction due to the effect of marine currents, the area of oil expansion is 1,739,000 m2, more than 24 beaches are contaminated, and the area impacted by the oil is 713 ha of sea and 180 ha of coastline, affecting the habitats and biodiversity of the Reserva Nacional Sistema de Islas, Islotes y Puntas Guaneras and the Zona Reservada Ancón. Nearly 500 species of marine algae, invertebrates, birds, and mammals have been affected. The Academy and public agencies should establish lines of research that include the management and conservation of species, to be carried out on the coasts of the Peruvian marine coast, in charge of specialized professionals, as well as provide the logistics and economic resources for the recovery and maintenance of marine biodiversity.

Role of initial energy reserves in stress tolerance thresholds during the early benthic phase in intertidal invertebrates

Although depleted energy reserves are not a major direct cause of early benthic phase mortality for many species of marine invertebrates, initial energy reserves might nevertheless play a role in early benthic phase mortality through indirect effects on physiological tolerance thresholds, a mechanism that has not been tested. We therefore examined the extent to which energy reserves affect acute tolerance thresholds of early benthic phase individuals of 2 species (Balanus glandula and Nucella ostrina) to 2 of the most challenging intertidal stressors: desiccation and high emersion temperature. Energy reserve levels were estimated by maintaining individuals without food for different durations of time or using individuals of different body mass. Individuals in each energy level treatment were then exposed to a range of desiccation periods and emersion temperatures. Lower estimated energy levels had no effect on tolerance to emersion temperature, but did significantly reduce the ability to tolerate desiccation. This suggests the survival of individuals through the early benthic phase is likely dependent on initial energy content through an indirect effect on tolerance to desiccation. Also, habitats experiencing intense desiccation likely impose a selective pressure on intertidal invertebrates favoring the evolution of greater energy reserves at the onset of the early benthic phase. These findings suggest depleted energy reserves at the onset of the early benthic phase can influence early benthic phase mortality through indirect effects by making individuals more vulnerable to environmental stressors. In this way, energy reserves may impact recruitment rates and thus influence population dynamics and intertidal community structure.

New Records of Rare Species of Marine Invertebrates in the Eastern Mediterranean, Syria

Conducting further research and exerting more effort into field studies will aid the detection and recording of new, rare species of invertebrates in the Mediterranean and allow the examination of their biological and environmental characteristics. This article provides information on four species of sea crab (one of which is alien), two species of sea star, one species of sea urchin and two species of octopus, which have all been documented for the first time in Syrian waters. Samples were collected by fishing nets from a coastal area at medium depths (20–630 meters) from Ras al-Basit, Lattakia and Banias during 2020 and 2021. These species are: Actaea savignii (H. Milne Edwards, 1834); Dromia personata (Linnaeus, 1758);Geryon longipes (A. Milne-Edwards, 1882); Homola barbata (Fabricius, 1793); Peltaster placenta (Müller and Troschel, 1842); Chaetaster longipes (Bruzelius, 1805); Sphaerechinus granularis (Lamarck, 1816); Tremoctopus violaceus (Delle Chiaje, 1830);Ocythoe tuberculate (Rafinesque, 1814). Documenting the presence of these rare species is very important from an environmental and scientific perspective, and recording more of them requires coordination with the marine fishing sector in Syria. KEYWORDS Cephalopods, crustaceans, echinoderms, marine biodiversity, non-indigenous species,zoobenthos

The Influence of Marina Characteristics on Non-native Colonisation

The marina properties, such as; salinity range, tidal fluctuations, depth, and ascidian presence in-fluence the distribution of invasive non-natives. Transport vectors, aquaculture and fishery practic-es also have an important role in the distribution of invasive non-native species during the bioinva-sion process. We focused on 10 invasive non-native species of marine invertebrates in the UK. This study explained the distribution and ecology of five invasive non-native species (Styela clava (As-cidia), Didemnum vexillum (Ascidia), Caprella mutica (Crustacea), Crepidula fornicata (Gastropo-da), Watersipora subtorquata (Bryozoa)) and the marina characteristics of five invasive non-native species colonization (Austrominius modestus (Arthropoda), Ciona intestinalis (Ascidia), Botrylloides violaceus (Ascidia), Tricellaria inopinata (Bryozoa), Bugula neritina (Bryozoa)) in Wales coasts. The study site deployed settlement tiles in the inner and the outer tile as two positions in each marina: An equal number of vertical and horizontal tiles was deployed at each site with half-sampled at two weeks (very early colonization) and at eight weeks (later colonization). The results showed that some variations in marina characteristics affected the distribution of invasive non-native species. Invasive non-native species abundance, diversity and multivariate structure of the assemblages were very high. The colonization of tiles varied between locations at the entrance and within the marina, but not in any way, and the effect of tile orientation was surprisingly low.

Algibacter onchidii sp. nov., a symbiotic bacterium isolated from a marine invertebrate.

A novel symbiotic bacterium, designated strain XY-114T, was isolated from the cerata of an Onchidium marine invertebrate species collected in the South China Sea. Strain XY-114T was an aerobic, Gram-stain-negative, non-motile and short rod-shaped bacterium (0.5-0.8 µm wide and 1.0-1.5 µm long) without flagellum. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain XY-114T belonged to the genus Algibacter with the highest similarity of 97.2 % to the closest phylogenetic relative Algibacter aestuarii KYW371T. Cells grew at 15-37 °C (optimum, 30 °C), at pH 5.5-9.0 (optimum 7.0-8.0) and at NaCl concentrations of 0.5-5.0 % (w/v; optimum 1.5-3.0 %). The major fatty acids (>10 %) were summed feature 3 (comprising C16 : 1 ω7c and/or C16 : 1 ω6c), iso-C15 : 0, iso-C15 : 1 G and iso-C17 : 0 3-OH. The predominant polar lipid was phosphatidylethanolamine. The predominant respiratory quinone was MK-6. Flexirubin-type pigments were absent. The genome size of strain XY-114T was 3.4 Mbp, with 34.9 mol% of DNA G+C content. The average nucleotide identity, digital DNA-DNA hybridization and amino acid identity values between strain XY-114T and A. aestuarii KYW371T were 74.5 %, 17.0±1.8 % and 73.9 %. Characterization based on phylogenetic, phenotypic, chemotaxonomic and genomic evidence demonstrated that strain XY-114T represents a novel species of the genus Algibacter, for which the name Algibacter onchidii sp. nov. is proposed. The type strain is XY-114T (=KCTC 72217T=MCCC 1K03606T).

Sinking Down or Floating Up? Current State of Taxonomic Studies on Marine Invertebrates in Japan Inferred from the Number of New Species Published between the Years 2003 and 2020.

Taxonomic studies on marine invertebrates have been prominent in Japan since the 19th century. Globally, taxonomy was reported to have been in recession since the early 21st century, but it is not clear if it is still in hardship or is making a recovery in recent years in Japan. In order to comprehend the status quo of taxonomic studies on marine invertebrates in Japan, we compiled a list of marine invertebrate species newly described from the exclusive economic zone of this country during the period between 2003 and 2020 and investigated trends by making comparisons of higher taxa and academic journals in terms of the numbers of new species and taxonomic authors. We noticed that recruitment of new researchers into taxonomic studies is evident in some taxa. We also found that certain articles with descriptions of new species are now being published in journals aimed at general biology/zoology, not oriented principally to taxonomy. We consider from our analyses that taxonomic studies on marine invertebrates in Japan show signs of resurgence, but development of new taxonomists is awaited in certain taxa.