The near-cosmopolitan genus Clytia is abundantly found in coastal waters, but difficulties of identification in this genus make nearly all species records of medusae suspect. Complex life histories, ambiguous taxonomic characters, and phenotypic plasticity pose serious problems for accurate species-level identifications and future revisions of Clytia species. In the present study, morphological investigations and molecular analyses of Clytia specimens from the coastal waters of the East China Sea revealed Clytia gulangensis sp. nov. as a new species. DNA barcoding based on the mitochondrial cytochrome oxidase I (COI) gene supported the new species as a separate species within Clytia, and phylogenetic analyses based on mitochondrial 16S rDNA and nuclear 18S rDNA further confirmed this new species to be a distinct lineage. Moreover, detailed observation of medusae and polyps of this species showed sufficient morphological differences from other Clytia species for a diagnosis. Our results indicated that life cycle and DNA-based studies should be a standard approach in future biodiversity investigations of Clytia species.

Marine worms in the genus Osedax, have specialized ‘root’ tissues used to bore into the bones of decomposing vertebrate skeletons and obtain nutrition. We investigated the borings of nine Osedax species, using micro computed tomography to quantitatively describe the morphology of the borings and provide three-dimensional reconstructions of the space occupied by Osedax root tissues inside the bone. Each Osedax species displayed a consistent boring morphology in any given bone, but these differed between bones. In bones where multiple species coexisted there was limited evidence for spatial niche partitioning by Osedax root tissues inside the bones investigated here. The new morphological data may be applied to Osedax traces in fossil bones, showing that borings can be used to indicate minimum species richness in these bones.

The size selectivity of traditional gillnets for whiting, (Merlangius merlangus euxinus) was investigated in the eastern Black Sea between June 2010 and June 2011. Experimental fishing operations were carried out by using gillnets of 16, 17, 18, 20 and 22 mm mesh size. A total of 2038 specimens belonging to 16 different fish species were caught during the experiment. The Share Each Length's Catch Total method was used to fit gillnet selectivity curves. Gillnet selectivity was best described by a bi-modal selectivity curve. The modal catch sizes were estimated as 14.81, 15.74, 16.66, 18.51 and 20.37 cm for 16, 17, 18, 20 and 22 mm mesh sizes, respectively. Modal lengths and spread values increased with increasing mesh size. The majority of fish (71.8%) caught by 16 mm mesh size were less than the length at first sexual maturity.