Since 2007, the non-indigenous calanoid copepod Pseudodiaptomus marinus Sato, 1913 has been increasingly recorded in numerous European sites, spreading at an unexpectedly fast pace over a short time-span. This species presents specific biological and behavioural traits which make it of particular interest for ecological and applied research topics. On 29-30 January 2018, 29 scientists from nine European Countries established the EUROBUS (Towards a EURopean OBservatory of the nonindigenous calanoid copepod Pseudodiaptomus mar-inUS) Working Group (WG). This WG aimed at creating a European network of institutions and researchers working on the various aspects of the Electronic supplementary material The online version of this article (

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Mortality, respiration rate, and body mass density of the estuarine copepods Calanipeda aquaedulcis and Arctodiaptomus salinus and their eggs were studied over a wide range of salinities. Empirical hydrodynamic modeling was applied to calculate body mass density using the sinking speed of the copepods. According to the index of median lethal salinity (LS 50 ), the salinity tolerance ranges of C. aquaedulcis and A. salinus reared at 18 psu were 0.1 to 50 and 0.1 to 35 psu, respectively. No significant effect of salinity on the specific oxygen consumption rate was found in the range from 0.1 to 40 psu in both species, while mean body mass density increased iso-osmotically with water salinity from (mean ± SD) 1.053 ± 0.007 to 1.077 ± 0.005 g cm −3 in C. aquaedulcis and from 1.039 ± 0.004 to 1.062 ± 0.007 g cm −3 in A. salinus. However, body density contrast and sinking speed were stable in both species, allowing them to avoid buoyancy problems with changing salinity. The mean mass density of resting eggs in A. salinus gradually increased isoosmotically following gradual changes in salinity. In contrast to resting eggs, the mass density of subitaneous eggs was not altered by changes in the surrounding salinity, suggesting a hysteresis response in these eggs.

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The article reviews the up-to-date concepts of an ambiguous status of the widely spread, bloom-forming, potentially toxic mixotrophic dinoflagellates Prorocentrum cordatum in marine planktonic food webs, with special emphasis on the ecological prerequisites of their proliferation and possible scenarios underlying the development of harmful algal blooms and their top-down control in marine coastal waters.

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The salinity tolerance and the effect of temperature were studied on the behavior and motor activity of the nonindigenous Indo‐Pacific calanoid copepod Pseudodiaptomus marinus, first found in Sevastopol Bay (Black Sea) in autumn 2016. According to the index of median lethal salinity (LS50), the salinity tolerance range of adult P. marinus collected at 18.0 psu in November 2016 and subsequently reared in the laboratory amounted to 5.0–44.0 psu, independently of the acclimation regime. Females of P. marinus collected in December 2016 at 12.0°C became torpid at 8.0°C, a value typical of winter–spring Black Sea coastal areas. An increase in temperature from 8.0°C to 27.0°C led to an increase in the beat frequency of mouth appendages, swimming speed, and time spent cruising. However, at the same high temperature, the mean cruising speed in the feeding‐current feeder P. marinus was 2‐fold lower than that of the native, similarly sized cruise feeder Pseudocalanus elongatus. On the contrary, mouthpart beat frequency while cruising was 2‐fold higher reaching 80 Hz, due to the creation of feeding currents in P. marinus. The results of our experiments confirm the euryhaline character of P. marinus, and point to an apparent ability to survive cold temperatures in a torpid state. This suggests the possibility of entering an overwintering stage to survive the adverse cold winter–spring environmental conditions of the Black Sea, similarly to the recent thermophilic Indo‐Pacific invader Oithona davisae which established a successful population in the same area.

The organochlorine compounds (OCs) contamination was studied in different tissues of the adult Black Sea turbot (BST) from natural spawning populations of 2008, 2009 and 2013 in the South-Western shelf off Crimea, the Black Sea. Total lipids, six congeners of polychlorinated biphenyl (CB 28, 52, 101, 138, 153, 180) and organochlorine pesticide p,p'-DDT including its metabolites p,p'-DDE and p,p'-DDD were measured in liver, red and white muscles and gonads of males and females of BST.In BST tissues sum of DDT compounds ranged on average from 2.5 to 223.9 ng . g -1 wet weight, and sum of six congeners of PCB dominated by hexa-CB 138 and 153 congeners had an overall range 2.0-234.3 ng . g -1 wet weight. The main DDT compound detected in BST were the metabolites p,p'-DDE and p,p'-DDD (83% of ΣDDT) indicative of old DDT residues. OCs concentrations positively correlated with extractable lipid content in BST tissues. Sex-related pattern of OCs accumulation in different tissues of BST was found. On average, OCs concentration (on wet weight basis) in liver was twice higher in male than that in female, while OCs concentration in gonads were lower in male than that in female