Aim The introduction of aquatic non‐indigenous species (ANS) has become a major driver for global changes in species biogeography. We examined spatial patterns and temporal trends of ANS detections since 1965 to inform conservation policy and management. Location Global. Methods We assembled an extensive dataset of first records of detection of ANS (1965–2015) across 49 aquatic ecosystems, including the (a) year of first collection, (b) population status and (c) potential pathway(s) of introduction. Data were analysed at global and regional levels to assess patterns of detection rate, richness and transport pathways. Results An annual mean of 43 (±16 SD) primary detections of ANS occurred—one new detection every 8.4 days for 50 years. The global rate of detections was relatively stable during 1965–1995, but increased rapidly after this time, peaking at roughly 66 primary detections per year during 2005–2010 and then declining marginally. Detection rates were variable within and across regions through time. Arthropods, molluscs and fishes were the most frequently reported ANS. Most ANS were likely introduced as stowaways in ships’ ballast water or biofouling, although direct evidence is typically absent. Main conclusions This synthesis highlights the magnitude of recent ANS detections, yet almost certainly represents an underestimate as many ANS go unreported due to limited search effort and diminishing taxonomic expertise. Temporal rates of detection are also confounded by reporting lags, likely contributing to the lower detection rate observed in recent years. There is a critical need to implement standardized, repeated methods across regions and taxa to improve the quality of global‐scale comparisons and sustain core measures over longer time‐scales. It will be fundamental to fill in knowledge gaps given that invasion data representing broad regions of the world's oceans are not yet readily available and to maintain knowledge pipelines for adaptive management.

Alexandrium is detected throughout Scottish coastal waters on a near annual basis, and corresponding paralytic shellfish poisoning (PSP) toxins are found in Scottish shellfish. Previous studies at selected Scottish sites have shown diversity within the genus Alexandrium. In order to examine the distribution, diversity and toxicity of Alexandrium populations around the Scottish coast, historic cyst and cell data were compiled and cultures established from sediment and water samples. Historic data showed high cell densities of Alexandrium in Shetland, Orkney, the Western Isles and mainland east coast. Low abundances of Alexandrium cysts were observed along the west coast. Four species of Alexandrium (A. tamarense, A. ostenfeldii, A. minutum and A. tamutum) were established in laboratory culture and identified using morphological criteria. Sequencing of LSU rDNA from isolates of A. ostenfeldii, A. minutum and A. tamutum confirmed their identification and showed them to be similar to other European strains. Alexandrium tamarense, identified by morphological criteria, was observed to have a widespread distribution around the coast. Both toxin-and non toxin-producing strains of this species were isolated, suggesting the presence of A. tamarense Groups I and III. Alexandrium ostenfeldii was isolated from the east coast and Shetland Isles and was observed to produce both spirolide and PSP toxins. Alexandrium tamutum was identified from cultures isolated from Shetland and Orkney, the most northerly observation of this species to date. PSP toxins were not detected in isolates of A. minutum from the east coast and Orkney or of A. tamutum under the culture conditions used. This study has highlighted the diversity of Alexandrium in Scottish waters and reveals the requirement for temporal and regional studies on a species level in order to understand the variation in cell densities and PSP toxicity that is observed on an annual and decadal scale.

Procedures for the isolation and characterization of Metha7zonzo?zas n~ethatto-oxidans Brown and Strawinslii are described. Isolates from varied sources are alike in cellular morphology, inasmuch a s they form only microcolonies, and in their dependence on methane or methanol as carbon and energy sources for growth. Both organic and inorganic nitrogen sources are used. The organism is a Gram negative non-sporeformillg rod, 1.5 to 3.0 p by 1.0 p in size, and motile by means of a single polar flagellum. In growing cultures the osygen/methane ratio was approsinlately 1.1 and in resting cells 1.7. The R.Q. for methane with resting cells was 0.43. Resting cells were unable t o oxidize organic compounds other than methane, methanol, formaldehyde, and formate. Formic acid was detected in test solutions after cell suspensions had metabolized methane, methanol, and formaldehyde. Using sodium sulphite as trapping agent for formaldehyde, it was found that 60 t o 70y0 of the methane or methanol consumed was converted to formaldehyde. I n the presence of iodoacetate, 70% of the methane consumed was present terminally as methanol. Thus i t was shown that methanol, formaldehyde, and formic acid are sequential intermediates in the osidation of methane by these organisms.In 1905 Kaserer concluded that inethane was oxidized by bacteria but he did not attempt t o isolate the responsible organisms. Shortly thereafter Sohngen (16) described a methane-oxidizing bacterium which he named Bacillus methanicz~s. Since that time, bacteria capable of utilizing inethane have been reported by inany ~vorlters including Munz (13), Giglioli and Masoni (9), Aiyer (I), A4ogilevsltii (12), Boltova, Kusnetsova, and I

Contamination of shellfish with paralytic shellfish poisoning (PSP) toxins produced by Alexandrium species poses a potential threat to the sustainability of the Scottish aquaculture industry. Routine LM analysis of water samples from around the Scottish coast has previously identified Alexandrium (Dinophyceae) as a regular part of the spring and summer phytoplankton communities in Scottish coastal waters. In this study, Alexandrium tamarense (M. Lebour) Balech isolated from sediment and water samples was established in laboratory culture. Species identification of these isolates was confirmed using thecal plate dissections and by molecular characterization based on their LSU and, in some cases, ITS rDNA sequence. Molecular characterization and phylogenetic analysis showed the presence of two ribotypes of A. tamarense: Group I (North American ribotype) and Group III (Western European ribotype). Assessment of PSP toxin production using hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) showed that A. tamarense Group I produced a complex array of toxins (∼2,000 fg STX equivalents · cell(-1) ) with the major toxins being C2, neosaxitoxin (NEO), saxitoxin (STX), gonyautoxin-4 (GTX-4), and GTX-3, while A. tamarense Group III did not produce toxins. Historically, it was considered that all Alexandrium species occurring in Scottish waters produce potent PSP toxins. This study has highlighted the presence of both PSP toxin-producing and benign species of A. tamarense and questions the ecological significance of this finding.

Species within the diatom genus Pseudo-nitzschia (Peragallo) have been identified as producers of domoic acid, the toxin responsible for amnesic shellfish poisoning. Toxin-and non-toxin-producing species of Pseudo-nitzschia have been reported globally; however, as Pseudo-nitzschia species cannot be routinely identified to species level using light microscopy, cells are rarely recorded to species level during long-term monitoring studies. Here, we report the results of a comparative survey of Pseudo-nitzschia species at two monitoring sites in the North Sea: Stonehaven on the east coast of Scotland and Helgoland Roads in the German Bight. A difference in the seasonality of this genus was observed between the sites with Pseudo-nitzschia cells playing a major role in the spring bloom as well at the summer and autumn diatom community at Stonehaven. In contrast, Pseudo-nitzschia was abundant only during the summer months at Helgoland. Pseudo-nitzschia cells constitute a higher proportion of the diatom community at Stonehaven than at Helgoland, particularly during the late summer, autumn and winter and thus may be considered more 'ecologically important' at this site. A total of eight different species were recorded during this survey with five Pseudo-nitzschia species observed at the Helgoland site: P. pungens, P. fraudulenta, P. americana, P. cf. delicatissima and the potentially toxic species P. multiseries. Six species were also recorded at Stonehaven; P. australis, P cf. delicatissima, P. pungens, P. cf. pseudodelicatissima, P. subpacifica and P. seriata. This study represents the first examination of the seasonality of Pseudo-nitzschia species around Helgoland and the first comparison between two long-term monitoring sites in the North Sea. P. americana and P. multiseries are also recorded at the Helgoland Roads time-series site for the first time.