Plastic Occurrence in Commercial Fish Species of the Black Sea

The occurrence of micro- (<5 mm), meso- (5–25 mm) and macroplastics (>25mm) was investigated in seven commercial fish species of the Black Sea. Plastics were found in gastrointestinal track of all species analysed: Engraulis encrasicolus, Trachurus mediterraneus, Sarda sarda, Belone belone, Pomatus saltatrix, Merlangius merlangus and Mullus barbatus. A total of 352 plastic particles were removed from 190 individuals (29% of all individuals examined). The mean number of plastic particles per fish was 0.81±1.42 par.ind-1 (considering all fish analysed, n=650) and 2.06±1.09 par.ind-1 (considering only the fish that ingested plastic, n=190). The most common types of plastics were fibres (68.5%), followed by films (19%), fragments (11.9%), foams (0.3 %) and microbeads (0.3%). The most common plastic colour was black (39.3%) followed by blue (19.5%) and transparent (18.1%). The length of plastics ranged from 0.05 to 26.5 mm with an average of 1.84±2.80 mm. 93.2% of plastics were microplastics, 6.5 % as mesoplastics and 0.3% macroplastics. Plastic occurrence was higher in S. sarda (plastic in 70% of the analysed individuals) and lower in M. merlangus (plastic in 9% of the analysed individuals). The main synthetic polymers identified by Fourier-transform infrared (FTIR) spectroscopy were polypropylene (29.8%), polyester (17.5%), acrylic (15.8%), polyethylene (14%) and polystyrene (1.8%) and 21.1% of polymers were cellulosic. Results show that commercial fish of the Black Sea is contaminated by plastics. This might affect vital functions of fish and pose a risk to ecosystem and human health. The study contributes to a better understanding of the status of plastic pollution in the fish from different habitats of the Black Sea and provides baseline data to implement the Marine Strategy Framework Directive in the basin.

Morphological and molecular identification of Cryptocotyle lingua metacercariae isolated from Atlantic cod (Gadus morhua) from Danish seas and whiting (Merlangius merlangus) from the English Channel

Trematode larvae (metacercariae) causing black spot disease occur frequently in gills, fins, skin and the superficial muscle layers of marine fish. Species within the genus Cryptocotyle Lühe, 1899 are frequently associated with this disease. Descriptions of the metacercarial stage are relatively limited and none has hitherto been reported from fish from the English Channel. The present study reports the morphological and molecular identifications of encysted black spot-inducing parasites from whiting (Merlangius merlangus) and Atlantic cod (Gadus morhua) caught respectively from the north coast of France (English Channel) and from Danish sea waters. Metacercariae were characterised morphologically based on microscopic observations and molecularly using Sanger sequencing of fragments of the mitochondrial cox1 gene and rDNA ITS region. Morphological data were compared with available data in the literature. Phylogenetic trees including reference sequences were built to confirm morphological and molecular identifications. This survey constitutes the first description of C. lingua metacercariae in the English Channel ecosystems.

Ихтиологические исследования на НИС «Профессор Водяницкий» у побережья Крыма и в районе Филлофорного поля Зернова в осенний период (2010 г.) и некоторые новые сведения об ихтиофауне Чёрного моря

После длительного периода отсутствия ихтиологических исследований на научноисследовательских судах Института биологии южных морей имени А.О. Ковалевского в Чёрном море (за исключением ихтиопланктонных съемок и прибрежных ловов на фелюге) они были проведены в 68-м рейсе НИС «Профессор Водяницкий» осенью 2010 г. Особый интерес представляют ихтиологические наблюдения в районе ботанического заказника Филлофорного поля Зернова, где аналогичные работы не проводились уже несколько десятков лет. В исследованиях были использованы удебные ловы, визуальные наблюдения и случайные поимки рыб. Впервые в этом Филлофорном поле поймана присоска пятнистая Diplecogaster bimaculata (Bonnaterre, 1788) на столь далеком расстоянии от берега, но при этом на глубине обычной для обитания вида. По современном видовому составу рыб Филлофорное поле Зернова можно охарактеризовать как относительно бедный район северо-западной части Чёрного моря. Трофическая цепь рыб представлена следующим образом: шпрот Sprattus sprattus (Linnaeus, 1758)→мерланг Merlangius merlangus (Linnaeus, 1758)→катран Squalus acanthias Linnaeus, 1758. В ихтиоцен поля Зернова входят как стайные пелагические виды – ставрида Trachurus mediterraneus (Steindachner, 1868), шпрот, так и придонные – мерланг, присоска. По сборам в этом районе уточнены максимальные размеры самцов черноморского мерланга – 18,8 см в эконом зонах бывшего СССР. В районе Батилимана отмечена самая глубоководная поимка морского конька Hippocampus hippocampus (Linnaeus, 1758) в Чёрном море.

Otolith chemoscape analysis in whiting links fishing grounds to nursery areas

Understanding life stage connectivity is essential to define appropriate spatial scales for fisheries management and develop effective strategies to reduce undersized bycatch. Despite many studies of population structure and connectivity in marine fish, most management units do not reflect biological populations and protection is rarely given to juvenile sources of the fished stock. Direct, quantitative estimates that link specific fishing grounds to the nursery areas, which produced the caught fish are essential to meet these objectives. Here we develop a continuous-surface otolith microchemistry approach to geolocate whiting (Merlangius merlangus) and infer life stage connectivity across the west coast of the UK. We show substantial connectivity across existing stock boundaries and identify the importance of the Firth of Clyde nursery area. This approach offers fisheries managers the ability to account for the benefits of improved fishing yields derived from spatial protection while minimising revenue loss.