Redistribution of the lizardfish Harpadon nehereus in coastal waters of China due to climate change

Climate change has the potential to greatly alter species distributions and threatens biodiversity in marine ecosystems. Mapping changes in species distribution patterns under climate change will help facilitate management strategies to maintain ecosystem structure and function. The lizardfish Harpadon nehereus is an aggressive predator that has experienced rapid population growth along the coast of China in recent decades, compressing the ecological niches of other marine species and disrupting food webs. If this species’ range is shifting due to climate change, it could further impact the integrity of ecological communities. To map the distribution of H. nehereus, we developed an ensemble species distribution model and projected the present and future habitat suitability in Chinese coastal waters. Annual mean benthic water temperature was identified as the most important variable affecting the projected distribution of H. nehereus, followed by water depth and salinity. Currently suitable habitats are along the coast from Guangxi Province to the southern Jiangsu Province. As climate changes, the southern portion of its distribution is predicted to recede with habitat losses, and the overall suitable habitat will shift northward. To avoid the potential impacts of H. nehereus redistribution, precautionary management based on species distribution modeling would help to maintain healthy marine ecosystems in the newly invaded areas.

     

First report of three benthic dinoflagellates,Gambierdiscus pacificus,G. australes and G. caribaeus (Dinophyceae), from Hainan Island,South China Sea

Species of the marine benthic dinoflagellate genus Gambierdiscus are the principal cause of Ciguatera fish poisoning. This genus has been recorded from tropical to temperate oceans, although Gambierdiscus species have rarely been found in Chinese waters. Our work revealed the morphological and genetic characteristics of three potentially toxic Gambierdiscus species observed in the temperate to subtropical waters of China. The fine thecal morphology was determined based on light microscopy and scanning electron microscopy analyses, and these species were also characterized by sequencing the D1–D3 and D8–D10 regions of the LSU rDNA. The morphological and genetic data indicated that these three Gambierdiscus species were G. pacificus, G. australes and G. caribaeus. This work provides the first report of these species in Chinese waters, which increases the known species distribution of this genus.     

Growth and mortality of exploited fishes in China's coastal seas and their uses for yield‐per‐recruit analyses

Given the scarcity of information suitable for other forms of fish stock assessments, the growth, and mortality of 10 important marine exploited fishes in China's coastal seas were estimated, based on published length‐frequency data and the ELEFAN approach and software. The resulting parameters, complemented with growth curves from FishBase were then used for yield‐per‐recruit analyses. These 10 species were both traditional commercial species (Trichiurus lepturus, Larimichthys polyactis, Scomber japonicus) and less commercial interest species (Coilia nasus, Engraulis japonicus, Decapterus maruadsi, Psenopsis anomala, Coilia mystus, Setipinna tenuifilis, Harpadon nehereus). The yield‐per‐recruit analyses indicated that the fishing mortality experienced by these 10 fish species was very high, especially in view of the extremely small cod‐end mesh sizes deployed by Chinese trawlers, of about 10 mm or less (vs. 25 mm as minimum legal size). More precisely, all 10 species suffered from growth overfishing, which was very pronounced in large species. Indeed, enlarging cod‐end mesh size, by increasing mean sizes at first capture, would increase yield‐per‐recruit for all 10 fish species by a factor of up to 2.5. Obviously, such increases in mesh size would have to be in tandem with other management measures designed to ensure the sustainability of China's marine fisheries resources.     

康氏菌科海洋细菌的系统发育与代谢潜能研究进展

康氏菌科(Kangillaceae)是海洋螺杆菌目(Oceanosprillales)下的科级分类单元,包含康氏菌属(Kangiella)、异康氏菌属(Aliikangiella)和Pleionea三个属.在康氏菌属高度精简的基因组中存在异常丰富的胞外蛋白酶编码基因,暗示此类海洋细菌对海洋颗粒有机物中的蛋白质成分降解具...     

Differential heavy metal sensitivity in seven algal species from the NIES culture collection based on delayed fluorescence assays

Seafloor massive sulfide (SMS) deposits are the target of available metallic resources. The toxic impacts of leachable metals from hydrothermal ore by mining operations in marine environments are a concern. However, ecotoxicological knowledge about marine algae, and particularly open ocean species, is still limited. Here, we evaluated the toxic effects of three leachable metals (i.e. Zn, Cu, and Pb) on seven marine algae, including cyanobacteria and eukaryotes, by a delayed fluorescence method. Cyanobacterial Synechococcus and Cyanobium species were sensitive to Zn and Cu, while eukaryotic algae showed various responses to heavy metal species. The prasinophycean Bathycoccus prasinos NIES‐2670 was sensitive to all metal species; this strain is a potential test strain to detect the leachable metals. A co‐culture experiment showed that the impact on community structure varies depending on leachable metal species. This study demonstrates that surveys across multiple taxonomic groups are necessary to assess the impact of SMS‐mining operations on marine ecosystems as a whole.     

南海东海岛近海固氮细菌多样性及对菜心的促生作用

海洋固氮细菌在自然界氮循环中发挥着重要作用,筛选和开发海洋固氮促生的菌种资源,对于生物菌肥的开发应用和农业生产具有重要意义。[目的]研究海洋固氮细菌的生物多样性及对陆地作物的促生作用,筛选优良的植物根际促生菌株。[方法]通过形态特征、生理生化试验和16S rRNA基因序列比对进行菌属鉴定;将解磷、解钾、产蛋白酶和纤维素酶等性能优良的菌株作为菜心盆栽试验的组合菌液,探究对菜心能否起促生作用。[结果]本研究从南海东海岛的海岛沉积物中筛选出18株固氮菌,分布在6个属9种,不动杆菌属4株,假交替单胞菌属1株,芽孢杆菌属8株,嗜冷杆菌属1株,海单胞菌属1株,交替单胞菌属3株。菜心幼苗经过组合菌剂的浇灌,在茎高、茎粗、最大叶宽和最大叶长4个指标均表明对菜心有显著的促生作用。其中,以芽孢杆菌属和不动杆菌属的菌株在菜心的生长过程中起关键的促进作用,对菜心的促生性能最佳。[结论]南海近海具有种类丰富多样的固氮细菌,以芽孢杆菌属和不动杆菌属的菌株促生作用最为显著,具有开发成微生物菌肥的潜力,为优良的海洋促生微生物菌种资源的定向利用及蔬菜的无公害生产提供重要依据。     

Unique Microbial Signatures of the Alien Hawaiian Marine Sponge Suberites zeteki

Invasive species poses a threat to the world’s oceans. Alien sponges account for the majority of introduced marine species in the isolated Hawaiian reef ecosystems. In this study, cultivation-dependent and cultivation-independent techniques were applied to investigate microbial consortia associated with the alien Hawaiian marine sponge Suberites zeteki. Its microbial communities were diverse with representatives of Actinobacteria, Firmicutes, α- and γ-Proteobacteria, Bacteroidetes, Chlamydiae, Planctomycetes, and Cyanobacteria. Specifically, the genus Chlamydia was identified for the first time from marine sponges, and two genera (Streptomyces and Rhodococcus) were added to the short list of culturable actinobacteria from sponges. Culturable microbial communities were dominated by Bacillus species (63%) and contained actinobacterial species closely affiliated with those from habitats other than marine sponges. Cyanobacterial clones were clustered with free-living cyanobacteria from water column and other environmental samples; they show no affiliation with other sponge-derived cyanobacteria. The low sequence similarity of Planctomycetes, Chlamydiae, and α-Proteobacteria clones to other previously described sequences suggested that S. zeteki may contain new lineages of these bacterial groups. The microbial diversity of S. zeteki was different from that of other studied marine sponges. This is the first report on microbial communities of alien marine invertebrate species. For the first time, it provides an insight into microbial structure within alien marine sponges in the Hawaiian marine ecosystems.     

Marine Oligochaeta of Jiaozhou Bay,Yellow Sea coast of China

Sixteen species of marine Oligochaeta (8 Tubificidae, 1 Naididae, 6 Enchytraeidae, 1 Megascolecidae) are recorded from the Qingdao area, at about 36° N on the Chinese Yellow Sea coast. Taxonomic remarks are given for most species, of which none appears new to science.Limnodriloides victoriensis Brinkhurst & Baker andEnchytraeus kincaidi Eisen, previously known from the Northeast Pacific, are described from Asia for the first time. These, as well asMonopylephorus rubroniveus Levinsen and aLumbricillus sp., are interpreted as members of a temperate fauna, while all the remaining species have previously been reported from Hong Kong (at about 22° N) and thus are regarded as subtropical/tropical forms in the Yellow Sea.     

A new surface gliding species of Chironomidae: An independent invasion of marine environments and its evolutionary implications

Insects have invaded marine habitats only rarely and secondarily. Recently, we discovered a flightless dipteran species skating rapidly on the surface of seawater ponds at the Pacific coast of eastern China. Morphological analyses initially suggested an isolated position of the non‐biting midge, suggesting the erection of a new genus within Chironomini (Diptera: Chironomidae). However, an analysis of molecular data revealed that the marine species is in fact nested within the species‐rich genus Dicrotendipes. The apparent conflict between molecular and morphological data can be easily explained. It is likely that the new species has evolved a series of autapomorphic adaptations. These traits clearly distinguish the taxon from other species of the genus but do not justify the erection of a new supraspecific taxon, which would render Dicrotendipes paraphyletic. The switch to marine environments was likely a trigger for various morphological modifications resulting from increased selective pressure. Molecular data suggest that the potential speciation event occurred around 19–29 Ma, linked with a migration from freshwater to seawater ponds along the Pacific Ocean. Considering the results of our analysis, we place the flightless marine skater in the genus Dicrotendipes. All life stages of Dicrotendipes sinicus Qi & Lin sp. n. are described and illustrated, associated with larvae obtained by rearing or confirmed through association with DNA barcodes. The biology and ecology of the species are outlined based on collection data and in situ observations. Evolutionary patterns linked with repeated invasions of marine habitats are discussed.     

The biotechnological potential of marine bacteria in the novel lineage of Pseudomonas pertucinogena

Marine habitats represent a prolific source for molecules of biotechnological interest. In particular, marine bacteria have attracted attention and were successfully exploited for industrial applications. Recently, a group of Pseudomonas species isolated from extreme habitats or living in association with algae or sponges were clustered in the newly established Pseudomonas pertucinogena lineage. Remarkably for the predominantly terrestrial genus Pseudomonas, more than half (9) of currently 16 species within this lineage were isolated from marine or saline habitats. Unlike other Pseudomonas species, they seem to have in common a highly specialized metabolism. Furthermore, the marine members apparently possess the capacity to produce biomolecules of biotechnological interest (e.g. dehalogenases, polyester hydrolases, transaminases). Here, we summarize the knowledge regarding the enzymatic endowment of the marine Pseudomonas pertucinogena bacteria and report on a genomic analysis focusing on the presence of genes encoding esterases, dehalogenases, transaminases and secondary metabolites including carbon storage compounds.     

BORON AS A GROWTH REQUIREMENT FOR DIATOMS1

A boron requirement has been shown for 12 species of marine pennate diatoms, 4 species of marine centric diatoms, and S freshwater diatom species. It can be concluded that boron is essential for the growth of most, probably all, diatoms. It is much easier to demonstrate a requirement for the marine species than for the freshwater species. Some species of marine algal flagellates also require boron for growth; others apparently do not.     

Penaeid and carid community changes in the St Lucia estuarine lake system,South Africa,under low water level,extended closed periods and marine reconnection conditions

Penaeid and carid communities were assessed in St Lucia over a wide range of saline conditions, water level conditions and mouth states, including a six-month marine connection and various connections to the Mfolozi Estuary. Samples were collected biannually in spring and autumn from November 2004 to May 2012 using seine nets. Seven penaeid and seven carid species were recorded, of which Palaemon pacificus, P. peringueyi, Penaeus indicus and Metapenaeus monoceros were the most abundant. The decline from 2004 to 2007 in both species recorded and densities of freshwater, estuarine and marine species during the initial closed period was linked to increased salinity, lack of recruitment and reduced estuarine surface area. Increased wave action and high seas following Cyclone Gamede opened the mouth in March 2007 after a 57-month closed period, resulting in recruitment of marine species, predominantly P. indicus, followed by a decline in densities after reclosure in August 2007. Increases in marine and freshwater species were evident after Mfolozi flood connections during 2008, 2009 and 2010. Highest densities were recorded after breaching in 2007 and after flood connections, highlighting the importance of a marine link to maintain the recruitment of penaeid species.     

Spatial and temporal variations and assemblage structure of fish species in Beymelek Lagoon,Turkey

Spatial and temporal variations and assemblage structure of fish species were investigated in Beymelek Lagoon, on the south‐western Mediterranean coast of Turkey. A total of 3956 fish, mainly juveniles, from 24 species representing 11 families were sampled by gillnets and trammel nets from February 2006 to January 2007. Twelve of the species were marine straddlers, 11 were marine‐estuarine‐dependent and one was catadromous. Numerical contribution of marine‐estuarine‐dependent species to the total fish abundance was 86.2%, while marine straddlers contributed only 13.8%. Despite the higher number of species, the numerical abundance of marine straddlers was lower than the abundance of marine‐estuarine‐dependent species. The contribution of catadromous species by number was only 0.02%. The assemblage was taxonomically dominated by Sparidae (seven species, 51.3%), Mugilidae (five species, 36.0%), and Clupeidae (one species, 10.3%). Among sparids, Sparus aurata, Diplodus sargus and Lithognathus mormyrus contributed 38.0, 7.2 and 4.6% to the total catch, respectively. The most abundant mugilid species was Liza saliens with 25.2%, followed by Chelon labrosus 5.2%, and Liza aurata 4.0%. Contribution by the other mugilid species to total catch was quite low. The Clupeidae (10.3%) were represented by Sardinella maderensis with 9.1% of the total catch. While the upper reaches of Beymelek Lagoon were dominated by Sparus aurata and Liza saliens, dominant in the lower reaches were Sardinella maderensis, Sparus aurata, Diplodus sargus, Lithognathus mormyrus and Liza saliens. Sparids were generally caught from mid‐summer to mid‐winter while mugilids were caught throughout the year. Clupeids occurred mainly from autumn to spring.     

Biogeography,habitat transitions and hybridization in a radiation of South American silverside fishes revealed by mitochondrial and genomic RAD data

Rivers and lake systems in the southern cone of South America have been widely influenced by historical glaciations, carrying important implications for the evolution of aquatic organisms, including prompting transitions between marine and freshwater habitats and by triggering hybridization among incipient species via waterway connectivity and stream capture events. Silverside fishes (Odontesthes) in the region comprise a radiation of 19 marine and freshwater species that have been hypothesized on the basis of morphological or mitochondrial DNA data to have either transitioned repeatedly into continental waters from the sea or colonized marine habitats following freshwater diversification. New double digest restriction‐site associated DNA data presented here provide a robust framework to investigate the biogeographical history of and habitat transitions in Odontesthes. We show that Odontesthes silversides originally diversified in the Pacific but independently colonized the Atlantic three times, producing three independent marine‐to‐freshwater transitions. Our results also indicate recent introgression of marine mitochondrial haplotypes into two freshwater clades, with more recurring instances of hybridization among Atlantic‐ versus Pacific‐slope species. In Pacific freshwater drainages, hybridization with a marine species appears to be geographically isolated and may be related to glaciation events. Substantial structural differences of estuarine gradients between these two geographical areas may have influenced the frequency, intensity and evolutionary effects of hybridization events.     

INFLUENCE OF FRESHWATER FLOW REGIME ON FISH ASSEMBLAGES IN THE GREAT FISH RIVER AND ESTUARY

Summary

Two and a half years of data were collected from the lower Great Fish River, head region and estuary to determine the fish species composition within these areas. Gilchristella aestuaria, Liza dumerilii, Rhabdosargus holubi and Pomadasys commersonnii were the four most abundant species captured, with riverine flow rate having an important effect on both species composition and numbers of fishes in the different regions. Most marine species displayed a strong inverse relationship between catch per unit effort and elevated freshwater inputs. Euryhaline marine species dominated the catches at all sampling sites during low flows but were less common during high flow periods when catadromous species were most abundant. Based on the available evidence it is suggested that for most marine species in the river this decline in abundance is related to low conductivity levels following floods rather than avoidance of elevated flows. The impact of elevated suspensoid concentrations and lowered dissolved oxygen concentrations on freshwater and estuarine fish populations during major river flooding is also discussed.     

Integrative taxonomy of Peniculus,Metapeniculus, and Trifur (Siphonostomatoida: Pennellidae), copepod parasites of marine fishes from Chile: species delimitation analyses using DNA barcoding and morphological evidence

Pennellidae is a family of copepod parasites of widely distributed marine fishes. The pennellid species are usually morphologically differentiated by cephalothorax, neck, trunk, and abdomen shape. These characters, however, show high polymorphism and therefore using only this type of data, delimitation at species level of this genus is difficult. In this study, we explored the genetic distances calculated from sequences of a DNA barcoding marker (COI mt) (678 base pairs). We also explored the genetic distances of 25 Peniculus specimens associated within nine marine fish species, four Metapeniculus specimens associated within one marine fish species, and four Trifur specimens associated within one marine fish species. All specimens were collected in Antofagasta Bay, Chile and were calculated from sequences of a DNA barcoding marker (COI mt) (678 base pairs). The genetic distance among the Peniculus specimens was 0.95% from the different host species, the Metapeniculus specimens distance was 0.44% and the Trifur specimens was 2.25%. Genetic difference between Peniculus and Metapeniculus was 17.86% and Peniculus differ from T. tortuosus by 18.16%. We analysed the barcoding gene fragment using Bayesian Inference (BI) for phylogenetic reconstruction using three outgroups. Based on the phylogenetic analysis an ultrametric tree was built and a general mixed Yule-coalescent (bGMYC) model was conducted for species delimitation. Morphometrics analyses were made with Bayesian statistics. Mean and credibility limit (95%) for each parameter was calculated. Results show that based on morphology the individuals collected can be assigned to P. cf. fistula von Nordmann, 1832, Metapeniculus antofagastensis Castro-Romero & Baeza-Kuroki, 1985, and Trifur cf. tortuosus Wilson, 1917. High morphological polymorphism was observed for the lineage of Peniculus associated to several host species of marine fishes. Similar results were obtained for Trifur cf. tortuosus parasites on Chilean marine fishes.     

Multivariate analyses of the biometric features from Philippine sardines – implications for the phylogenetic relationships of the freshwater Sardinella tawilis (Teleostei,Clupeomorpha)*

Philippine sardines are members of the commercially important Sardinella genus (Family Clupeidae). Sardines are mostly marine species with a very few exception like the Philippine freshwater sardine, Sardinella tawilis, of Lake Taal. This species is believed to have immigrated from Balayan Bay some 250 years ago. To determine the relationship of freshwater S. tawilis to the marine forms, 35 biometric features were investigated. The variables were subjected to univariate (mean, standard deviation and coefficient of variance) and multivariate analyses [Principal Component Analysis (PCA) and Hierarchical Cluster Analysis]. Results from univariate tests revealed that the number of ventral fin ray can discriminate Sardinella lemuru from the rest of the sardines. Multivariate PCA, on the other hand, showed discrete separation of the marine sardines. Sardinella tawilis, however, cannot be clearly separated from the marine species, Sardinella albella. The same clustering was recovered in HCA, thus providing evidence that S. albella is the closest marine relative of the freshwater S. tawilis.     

A single origin for the limnetic–euryhaline taxa in the Corbulidae (Bivalvia)

The bivalve family Corbulidae, known colloquially as ‘basket clams’, includes species tolerating a wide variety of habitats ranging from open marine to freshwater. Previous studies of corbulid phylogenetics have been based mainly on shell morphology and to some extent soft tissue anatomy. However, these studies have been inadequate for corbulid classification because of difficulties in determining the inter‐relationships of primarily marine species with non‐marine species, the latter commonly exhibiting highly divergent morphological, ecological and environmental characteristics from their marine counterparts. The first molecular phylogenetic study of the Corbulidae is presented herein, analysing DNA sequences from the 18S rRNA and 28S rRNA genes, separately and in combination. Fifteen corbulid species and 14 outgroup taxa were included in the analyses. Corbulidae is resolved as monophyletic, comprising three groups with varying support. The non‐marine species form one group that we name as the subclade ‘limnetic–euryhaline Corbulidae’ (LEC) and comprising the genera Lentidium, Erodona and Potamocorbula. This LEC, which is consistently recovered as monophyletic, is globally distributed. The marine Corbulidae are divided into two well‐supported lineages in combined analyses although there are inconsistencies in their membership between single‐gene analyses. One of the two lineages consists of primarily Western Pacific taxa and the other of North American and Caribbean taxa. Finally, the authors advocate further study on the LEC to mitigate potential biological invasions beyond their native distribution.     

Phenotypic and molecular characterisation of <Emphasis Type="Italic">Brucella</Emphasis> isolates from marine mammals

Background  

Bacteria of the genus Brucella are the causative organisms of brucellosis in animals and man. Previous characterisation of Brucella strains originating from marine mammals showed them to be distinct from the terrestrial species and likely to comprise one or more new taxa. Recently two new species comprising Brucella isolates from marine mammals, B. pinnipedialis and B. ceti, were validly published. Here we report on an extensive study of the molecular and phenotypic characteristics of marine mammal Brucella isolates and on how these characteristics relate to the newly described species.