A new suprabenthic mysid, Mysidopsis cachuchoensis sp. nov., is described from specimens sampled with a suprabenthic sled at the ‘Le Danois' Bank (the ‘El Cachucho' Marine Protected Area; southern Bay of Biscay). The main distinguishing features of this new species are the structure of its eyestalk and antennal scale as well as the armature of its telson and uropodal endopods. Inferred from the present unique record (828 m depth, inner basin between the bank and the Cantabrian shelf), it seems to be a rare endemic species of the bank, living on muddy bottoms of the upper bathyal.

Distribution, reproductive biology and biochemical composition of Rhopalophthalmus indicus were investigated based on samples collected over a period of one year from Cochin backwater. Rhopalophthalmus indicus was recorded throughout the year with peak abundance during pre-monsoon. The population density was influenced by chlorophyll-a, dissolved oxygen, salinity and water temperature. The species showed periodicity in the abundance and produced more than one generation per year. The number of embryos carried by a single female ranged from six to 13, and was correlated with female body length (P > 0.05), tending to increase with the size of the female. Egg size varied between 0.42 and 0.47 mm, and was independent of female size. Both males and females attain sexual maturity at a length of 8.4 mm. Seasonality is observed in biochemical composition, as mature males and females had higher protein contents, immature stages contained high carbohydrate content and brooding females accumulated more lipids.