First record of a wild population of the tropical snail Melanoides tuberculata in New Zealand natural waters

The thiarid snail Melanoides tuberculata (Müller, 1774), native to the Middle East and East Africa, is recorded from the wild in New Zealand for the first time from a geothermally influenced stream at Golden Springs, near Taupo. Introduction was most likely the result of one or more releases from tropical aquaria, although the timing of release is uncertain. Specimens were collected at temperatures of 29.0 and 30.4°C, and survival at these sites is likely dependent on the elevated stream temperatures. The possible spread of this species to other habitats, and potential effects on native thermal water communities, are discussed.     

Invasive Spartina alterniflora-induced factors affecting epibenthos distribution in coastal salt marsh, China

Artificially introduced cordgrass, Spartina alterniflora, rapidly colonized the intertidal flats of the Jiangsu coast, eastern China. The epibenthos on an intertidal flat invaded by S. alterniflora were studied, to identify how local epibenthos species react to an altered environment. Epibenthic samples and surficial sediment samples were collected along a shore-normal profile in 50 quadrats at ten stations across the Spartina salt marsh; and five control quadrats for a station located on the barren sandy-mud flat. The grain size parameters of the surficial sediments show that S. alterniflora altered the grain size gradient along the profile of the intertidal zone by trapping fine-grained sediments. Spartina alterniflora could inhabit lower elevations than indigenous salt marsh vegetation, thus creating larger areas of finer surficial sediments, which was suitable for not only native epibenthic species but also species which do not exist on the barren sandy-mud flat. Correlation analyses show that the epibenthos were sensitive to sediment grain size and type, on the invaded S. alterniflora salt marsh. Further, there was an interspecific relationship affecting the distribution of epibenthos. The results show that epibenthos preferred ecological niches, within the Spartina salt marsh, even in the same sampling station.     

Optimizing Remote Sensing and GIS Tools for Mapping and Managing the Distribution of an Invasive Mangrove (Rhizophora mangle) on South Molokai,Hawaii

In 1902, the Florida red mangrove, Rhizophora mangle L., was introduced to the island of Molokai, Hawaii, and has since colonized nearly 25% of the south coast shoreline. By classifying three kinds of remote sensing imagery, we compared abilities to detect invasive mangrove distributions and to discriminate mangroves from surrounding terrestrial vegetation. Using three analytical techniques, we compared mangrove mapping accuracy for various sensor-technique combinations. ANOVA of accuracy assessments demonstrated significant differences among techniques, but no significant differences among the three sensors. We summarize advantages and disadvantages of each sensor and technique for mapping mangrove distributions in tropical coastal environments.     

南海西北部陆架区沿岸流和上升流对中华哲水蚤分布的影响

中华哲水蚤(Calanus sinicus)是广泛分布于西北太平洋大陆架水域的浮游桡足类,在海洋生态系统的物质循环和能量流动中具有重要作用。根据2006年7月至2007年10月4个季节使用网目孔径为0.505mm的浮游生物网采集的样品,分析了南海西北部陆架区中华哲水蚤的水平、季节和昼夜垂直分布以及与季风、海流和温度的关系。中华哲水蚤丰度季节变化显著,整个调查海域春季的平均达(22.30±77.78)个/m3,夏季的降低,平均为(13.74±45.10)个/m3,秋季消失,冬季调查期间仍未出现。中华哲水蚤的区域分布差异十分显著,将调查海域划分为粤西近海、琼东近海、粤西-琼东外海三个亚区,在粤西近海亚区春、夏季中华哲水蚤的平均丰度分别为(115.63±145.93),(68.12±84.00)个/m3,远高于另外两个亚区。夏季琼东沿岸上升流区的中华哲水蚤没有昼夜垂直移动行为,呈底层分布,以躲避表层高温的伤害。南海西北部陆架区是中华哲水蚤的季节分布区,冬春季东北季风期间由广东沿岸流从东海沿岸携带而来,出现的时间从北往南逐渐推迟;夏季西南季风期间雷州半岛东部近海的冷涡和琼东沿岸上升流区成为中华哲水蚤度夏的避难所;秋季季风转换时期上升流减弱或消失,中华哲水蚤因耐受不了高温(>27℃)死亡而消失。因此,中华哲水蚤对东北季风时期的沿岸流和西南季风时期的上升流均具有良好的指示作用。     

水产品鲐鱼(Pneumatophorus japonicus)细菌多样性及优势微生物分析

为研究鲐鱼(Pneumatophorus japonicus)在不同冻藏时期的优势微生物,并且得到一个较全面的细菌群落组成结构,采用16SrDNA基因克隆文库及克隆子分析等方法,分别对冻藏1d、8d和20d条件下鲐鱼鳃体系中的细菌种群多样性、优势微生物及其中产组胺菌的变化进行分析。结果表明,不同时期鲐鱼鳃内的细菌多样性均较强;冻藏1天的鳃体系中不动杆菌属(Acinetobacter)占优势为总数的77.5%,产组胺细菌如泛菌属(Pantoea)和肠杆菌属(Enterobacter)较少;第8天优势细菌种群是梭杆菌属(Fusobacteria bacterium)和希瓦氏菌属(Shewanella),而产组胺菌如发光杆菌属(Photobacterium)和弧菌属(Vibrio)较前期数量有所增加;冻藏到第20天的优势种群为哈夫尼菌属(Hafnia)和沙雷菌属(Serratia),它们均是产组胺的菌群。鲐鱼中细菌多样性及其优势微生物的变化等全面信息可为了解鲐鱼水产品组胺发生的微生物机制及其控制方法提供重要依据。     

Tube-forming polychaetes enhance invertebrate diversity and abundance in sandy sediments of Mozambique,Africa

In marine soft-bottom systems, polychaetes can increase habitat complexity by constructing rigid tubes (e.g. several onuphid species) that contrast with surrounding topographically flat sediments. These structures can provide predation refuges and increase larval settlement and thereby increase the richness and abundance of fauna. We collected invertebrate samples from an intertidal flat with low onuphid tube density (2.7 m^–2) in Mozambique and document that more organisms (70 times higher mollusc abundances) and more species (15 times more mollusc species) were found associated with solitary tubes of an onuphid polychaete compared with surrounding sand habitats. These results are in agreement with tube versus sand comparisons from soft-bottom systems in the North Atlantic where polychaete tube densities are often much higher.     

The barnacles Chirona (Striatobalanus) amaryllis (Darwin 1854) and Megabalanus coccopoma (Darwin 1854) (Crustacea,Cirripedia): two invasive species new to tropical West African waters

The collection of the barnacle Chirona (Striatobalanus) amaryllis (Darwin 1954) (Crustacea, Cirripedia) from the hull of a ship that had been operating for five months in the Gulf of Guinea and off Sierra Leone triggered a closer investigation of the cirriped fauna of the West African coast. Both C. amaryllis and Megabalanus coccopoma can now be added to the list of successful invasions in tropical West African waters. This discovery, as well as the circumstances of the findings, necessitates an update of the invertebrate faunal inventory of tropical West African marine waters.     

In situ video observations of benthic megafauna and fishes from the deep eastern Mediterranean Sea off Egypt

Remotely operated vehicle (ROV) video observations were used to document benthic fauna at a hydrocarbon drilling location, at 2 720 m depth, in the poorly studied deep water off northern Egypt. The decapod Chaceon mediterraneus was the most common organism at the site and the only benthic megafaunal invertebrate observed. Three species of fish, Coryphaenoides mediterraneus, Cataetyx laticeps and Bathypterois mediterraneus, were also encountered. These findings confirmed these three species as the deepest-distributed benthic fish in the eastern Mediterranean, and confirmed that the deep Mediterranean, in particular the eastern basin, is one of the world's poorest deep-sea ecosystems in terms of diversity. The behaviour exhibited by the species observed was consistent with their natatory capacity, deduced from their feeding intensity (gut fullness) and diet (mainly suprabenthic prey were consumed), and conservative life strategies adapted to an extremely low energy environment.     

Myosotella myosotis (Mollusca: Ellobiidae) — an overlooked,but well-established introduced species in South Africa

Myosotella myosotis is shown to be a well-established alien species in South Africa. Discovered in Port Elizabeth more than 100 years ago, it was initially thought to be indigenous and was described under two different names, but subsequent taxonomic work has demonstrated that these are synonyms of the variable and widely introduced European M. myosotis. This information, published in a revision of western Atlantic Ellobiidae, has escaped the attention of the South African marine science community. There has been no recent mention of M. myosotis or its two pseudoindigenous synonyms in the literature pertaining to either the estuaries or the malacofauna of South Africa, or to marine bioinvasions in the region. This example serves to demonstrate that invasion biology has a global context and that taxonomic literature is an important source of pertinent data. The fact that a species, which evidently occurs in abundance, can be overlooked for so long is both surprising and sobering.     

Fifty-five-year longevity for the largest member of the family Sparidae: the endemic red steenbras Petrus rupestris from South Africa

A previous study that explored the age and growth of red steenbras Petrus rupestris (Valenciennes, 1830), a large sparid (family Sparidae, seabreams or porgies) endemic to South Africa and reported to approach 2 m in length, provided estimates as a moderately slow-growing species with a maximum age near 30 years. The stock is considered collapsed and a fishing moratorium was imposed in 2012, resulting in this species being assessed as Endangered by the IUCN. One consideration in addressing population status is validation of life-history traits. In this study, estimates of age for red steenbras from thin-sectioned otoliths were reassessed visually in terms of both the original ages and revised estimates using a different age-reading pattern. The revised ages exceeded the original ages by up to 30 years, with a maximum estimated age of 55 years from a well-defined otolith section that provided a basis for the revised age-reading procedure. Bomb radiocarbon (¹⁴C) dating revealed there was an offset in the timing of the ¹⁴C rise on the Agulhas Bank that, when coupled with considerations for regional oceanography, provided support for the revised age-reading pattern and an estimated longevity that exceeds 50 years. These findings were further supported by the fortuitous recapture of a tagged red steenbras that was at liberty for 22 years.