Eriocheir sinensis, the Chinese mitten crab, is a native of east Asia and predominantly lives in freshwater but migrates seawards to breed. In 1912 a specimen was collected in the River Aller, a tributary of the Weser, Germany and now this exotic species has a European distribution from Finland to the Atlantic coast of southern France. In the UK, the mitten crab has been reported from the Humber, Medway and Thames catchments. Although the population in Thames had remained low, recent evidence suggests it is increasing, which has potential environmental implications.

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An investigation of two subtidal caves in the eastern exposed waters of Hong Kong was undertaken in 2002. The geological context and the physical parameters of the cave environments are described. The caves, or zawns, occurring at depths of between 29.3 to 212.4 m C.D. and 21.8 to 218.2 m C.D. at Steep Island and Conic Island, respectively, were probably created at a time of lowered sea levels during the last ice age .19,000 years ago. The caves have subsequently been drowned and each now possesses a floor that is covered in muddy sand. The present paper sets the context for the range of taxonomic and ecological studies undertaken during the 2002 Hong Kong Marine Caves Expedition.

At the request of TOTAL E&P Angola (TEPA), before developing oil and gas activity, independent contractors carried out seven environmental baseline studies between 1998 and 2009 on bathyal blocks 17 and 32 located off the coast of Angola. With this aim, biological analysis were done on seabed samples at depths ranging between 682 and 2630 m, and 515 benthic macrofaunal taxa from eleven phyla were discovered. The relative dominance on richness taxonomic and abundance was observed on Polychaetes, but referring to species' abundance it was found the sipunculid Onchnesoma steenstrupi (78 ± 72 ind./m²) with the major representation in samples (94%). The general composition of benthic macrofauna communities was very similar between sites despite the wide range of depths. This suggested relatively high ecosystem homogeneity in space and time. Average taxon richness per station (41 ± 11) was relatively high and the Shannon-Weiner diversity index very high (4.5 ± 0.5). Total density was relatively low (409 ± 179 ind./m²), as well as dry weight total biomass (0.57 ± 1.27 g/m²). Such levels of structural indices were consistent with common deep-sea soft sediment records. Increasing biodiversity from deep offshore Block 17 sites to ultra-deep offshore Block 32 area also was concordant with previous deep Angola Basin observations. When performing the taxonomic identification of species encountered in this work, it was estimated that about 80% of species found in both blocks were new to science. In respect of trophic structure of the groups, it was found that there was dominance of detritus deposits in relation to suspension feeders. Finally, it was also concluded that the state of the environment was stable, the ecosystem was in equilibrium and there was a high level of biodiversity.