The objective of this study was to find a technique for plant resistance screening to alternaria leaf blight (ALB), caused by the fungus Alternaria dauci , in controlled environments. Glasshouse and laboratory screening methods were compared using three cultivars and F 2 genotypes segregating for ALB resistance evaluated against self-pollinated F 3 fieldgrown plants. Plant disease was assessed through a disease index obtained from the size and number of symptoms on carrot leaves. The results indicated the value of glasshouse evaluation and the inadequacy of detached leaf and hypocotyl assays for carrot screening for ALB resistance. Spearman's rank correlation, applied to results obtained with both F 2 plants and their progeny, indicated that the optimal evaluation stage for ALB resistance in carrot is 20 days after inoculation. This test was powerful enough to be used as a prescreening test in breeding programmes.

In most production areas, Alternaria leaf blight (ALB) is recognized as the most common and destructive foliage disease in carrot. To assess the genetic architecture of carrot ALB resistance, two parental coupling maps were developed with similar number of dominant markers (around 70), sizes (around 650 cM), densities (around 9.5 cM), and marker composition. The F(2:3) progenies were evaluated in field and tunnel for two scoring dates. The continuous distribution of the disease severity value indicated that ALB resistance is under polygenic control. Three QTLs regions were found on three linkage groups. Two of them were tunnel or field specific and were detected only at the second screening date suggesting that the expression of these two QTLs regions involved in resistance to Alternaria dauci might depend on environment and delay after infection.

Twaite shad Alosa fallax (12 -48 cm total length) from the Gulf of Gdansk feed on Mysids: Mysis mixta, Neomysis integer, and fish: Sprattus sprattus, Osmerus eperlanus, and Pomatoschistus sp.. In the stomachs of A. fallax there also occur Hydrobia sp., Diptera and small stones, particles of wood and plastic. The food of inshore twaite shad measured from 12 to 21 cm centered on M. mixta. Fish are the main prey for A. fallax from the class length 22 -31 cm from the Vistula River mouth and for all shads longer than 32 cm.

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Studies of cyanobacterial bloom dynamics show that the highest biomass accumulation of Nodularia spumigena is observed in the shallowest area of the Gulf of Gdańsk in summer. In the same region and time, the highest fish abundance is observed. Mostly young individuals of gobies, small sandeel, flounder, three-spine stickleback and young herring occur. In this work we compare how toxic blooms of cyanobacteria influence the number and structure of fish communities in a coastal zone. The results obtained in our study were rather unexpected. More fish species were caught and the biomass of fish was higher during a bloom than in a month following the sampling (no bloom).