Parasite community diversity in two Mediterranean labrid fishes Symphodus tinea and Labrus merula

Examination of 111 peacock wrasse [Symphodus tinea (L.)] and 97 brown wrasse ( Labrus merula L.) from the Valencian coast (Spain) yielded 24 metazoan parasite species (11 Digenea, three Cestoda, four Nematoda. one Acanlhocephala, five Crustacea). Eighteen species were from 5. tinea and 17 from L. merula; 11 of the 24 species were common to both hosts. Brillouin's diversity index, was applied to fully censused parasite infracommunities. This is the first time that all the metazoan parasites (internal and external) in any position in the host have been analysed for diversity. High values of prevalence, intensity, and diversity parameters indicate that these labrid fishes support diverse parasite communities. This may be due to their diverse diet, mainly marine invertebrates which are possible intermediate hosts; they also support certain netnatodes and crustaceans which have direct life-cycle.     

Levels of genetic variability in sculpins (Gottidae: Teleostei) of the North American Pacific coast and an assessment of potential correlates

We examined levels of allozymic variation in intertidal sculpins of the genera Oligocottus, Clinocottus and Artedius. Variability in these species, as assessed by the proportion of loci polymorphic and average heterozygosity per locus, was generally low but within the range of values observed for other fish groups. In reviewing the ecological and life-history attributes of these sculpins, we found only one outstanding correlate of allozyme variability–larger-bodied species tended to have lower levels of variation. Also, the level of heterozygosity was not related in any obvious way to historical/ evolutionary aspects such as position in phylogenetic trees or the inferred relative ages of species. Our study of a relatively well-defined lineage of fishes that co-occur in the same geographical region and in the same, or broadly similar, habitats, underscores the difficulty of detecting correlations between genetic variability and seemingly relevant ecological features of species.     

Anaerobic degradation of dimethylsulfoniopropionate to 3-S-methylmercaptopropionate by a marine Desulfobacterium strain

Dimethylsulfoniopropionate, an osmolyte of marine algae, is thought to be the major precursor of dimethyl sulfide, which plays a dominant role in biogenic sulfur emission. The marine sulfate-reducing bacterium Desulfobacterium strain PM4 was found to degrade dimethylsulfoniopropionate to 3-S-methylmercaptopropionate. The oxidation of one of the methyl groups of dimethylsulfoniopropionate was coupled to the reduction of sulfate; this process is similar to the degradation betaine to dimethylglycine which was described earlier for the same strain. Desulfobacterium PM4 is the first example of an anaerobic marine bacterium that is able to demethylate dimethylsulfoniopropionate.Abbreviations DMSP dimethylsulfoniopropionate - DMS dimethyl sulfide - MMPA 3-S-methylmercaptopropionate     

Planktivory in benthic nototheniid fish in McMurdo Sound,Antarctica

Synopsis Four species of nototheniid fish were sampled from below the sea ice near Cape Armitage, McMurdo Sound:Pagothenia borchgrevinki from just below the ice 1.5 km offshore,Trematomus bernacchii, Trematomus hansoni andTrematomus centronotus from off the bottom in about 20 m of water near the shore. Scale worms and isopods were conspicuous non-planktonic prey, and present in the three benthic fish species. The planktonic pteropod molluscLimacina helicina was numerically common in all four species of fish. The planktonic hyperiid amphipodHyperiella dilatata was also found in all fish species. WhereasP. borchgrevinki is planktivorous in accord with its pelagic habit, theTrematomus spp. clearly also feed on plankton from the water column.T. hansoni is particularly planktivorous, taking smaller copepods thanP. borchgrevinki.     

Comparison of fatty acids of marine fungi using multivariate statistical analysis

Summary Ten obligate marine fungi have as their principal fatty acids 160, 180, 181n9 and 182n6. The fatty acids ranged from 14 to 22 carbons, completely dominated by those with even numbers of carbons. The amount of unsaturated fatty acids varied between 35% and 80%. Each isolate contained small amounts of the acids 183n3 and 204n6. Branched, hydroxy- or cyclic fatty acids were not detected. Multivariate statistical, i.e. principal component analysis, showed that all ten strains could be distinguished on the basis of their fatty acid composition. These results indicate that the marine fungi do not have an unusual fatty acid composition and suggest that chemometric, multivariate analysis might be employed to confirm taxonomic relationships among these organisms.     

北部湾鱼类碳、氮、磷生态化学计量特征

为探究北部湾鱼类生态化学计量特征,于2021年3月—4月采集分析了北部湾沿岸9个渔港的79种鱼类(382尾)碳(C)、氮(N)、磷(P)含量特征。结果表明北部湾鱼类C、N、P元素含量变化范围分别为33.87%—58.34%、6.31%—14.92%和0.77%—4.67%;C∶N、C∶P、N∶P的变化范围分别为3.43—9.72、19.15—173.06和5.04—33.68,其中P元素含量变化最大,导致C∶P和N∶P的变化。不同物种在科间的差异较大,科内的差异较小。不同体型和食性鱼类之间的C、N、P含量及比值具有显著差异(P<0.05)。鱼类的C∶P和N∶P与P含量呈显著负相关(R²=0.966,P<0.01;R²=0.877,P<0.01),P含量和Ca含量呈显著正相关(R²=0.919,P<0.01),P含量的变化可能与鱼类骨骼和鳞片的形成有关。总之,北部湾鱼类未保持严格的生态化学计量平衡,鱼类生态化学计量特征存在显著的种间差异,主要因鱼类不同的体型和食性差异所致。     

Game theory-based stakeholder analysis of marine nature reserves and its case studies in Guangdong Province,China

Marine nature reserves (MNRs) play an important role in biodiversity conservation and ecosystem restoration, which are valuable for marine resource protection in China. Many stakeholders are involved in MNRs. The interactions between MNR managers and other stakeholders affect the effectiveness of MNR management. This work divided MNR stakeholders into three categories and applied the analytical hierarchy process (AHP) to identify the key stakeholders. The game model was set up to analyze the strategies of MNR staff and stakeholders. The situation of key stakeholders and management was studied in two MNRs in Guangdong Province through field research and questionnaires. The results showed that fishermen were the main stakeholders in the two cases. The strategies adopted by MNR staff to improve the efficiency of law enforcement and decrease the probability of illegal activities of fishermen are to increase penalties, improve the arrest rate of illegal activities, and reduce the cost of law enforcement per patrol. We suggested that the fishermen’s negative impacts could be minimized by establishing a market management system to reduce illegal earnings, a record-keeping system to share additional benefits only with the fishermen who comply with the law, and an association mechanism in the coastal province to control illegal fishing across provincial boundaries. Identifying key stakeholders and analyzing their relationships could be helpful to find out the best strategy for different MNRs. Building a community of shared interests among various stakeholders could be a promising way to resolve conflicts and improve management effectiveness in MNRs.     

Algae-associated marine molluscs in the Azores

The raolluscan fauna of a special habitat, the high intertidal algal turf, was studied at four stations on the island of Sao Miguel, Azores. The number of species found ranged from 13 to 23. However, a small group of only six species (the bivalve Lasaea adansoni and the gastropods Pisinna punctulum, Omalogyra atomus, Fossarus ambiguus, Skeneopsis planorbis and Alvania postrema) accounted for more than 80% of all the specimens collected. Mollusc density reached values of 20000 specimens per 100 g algal dry weight. The abundance and number of species of molluscs was comparable with those reported for algal zones lower on the Azorean shores.
Wave exposure and seasonality effects were found to be small, presumably because of the relatively mild abiotic conditions and the protective role of the turf. The algal substrata influenced the phytal molluscan community in two ways. First, the abundance of molluscs was significantly correlated with algal dry weight. Secondly, molluscan abundance and diversity were influenced by the algal composition of the turf. A rich algal composition, with several species of branched fleshy and coralline algae, was associated with a rich molluscan fauna. The dominance of coralline algae resulted in a abundant but species-poor fauna, while an almost monospecific turf of Gigartina was poor in both species and number of molluscan fauna.     

青藏高原动物地理区的地位和东部界线问题

本文从历史时空的角度分析了青藏高原地区发生的鱼类区系的变化过程,和高原鱼类区系演化的相对独立性,认为这一鱼类区系的分化直接反映了高原隆升事件,并应当在动物地理区划上得到客观反映,即将青藏高原作为一个独立的区划单元。由于青藏高原的隆升和造成古北区、东洋区分化的第三纪末、第四纪初的全球性气候变冷在时间上相近、波及的范围都巨大,共同促成了欧亚大陆古北区、东洋区和青藏高原区特有类群的分化,作为对这些地史事件反映的青藏高原区、古北区和东洋区,在动物地理区划上应该具有相同的地位．另外,依据高原鱼类的分布范围和青藏高原对非高原鱼类的阻碍作用,讨论了青藏高原的界限及其划分问题。     

东亚似鮈类鱼类的起源和演化

本文采用分支扩散法和分支离散法两种生物地理学方法分析了似　类的起源和演化。结果说明似类于第三纪末起源于中国北方的原始类,逐步向南扩散。在其物种分化过程中可能存在南北两个分化中心。