The mantis shrimp Rissoides desmaresti in the Solent and around the Ise of Wight.

Abstract

The burrowing mantis shrimp Rissoides desmaresti (Risso, 1816) is considered scarce in the British Isles where populations are at the northern edge of their geographical range. Yet parts of the Solent region have been a known ‘hot spot’ since the mid-19th Century. From 2004-2007, a local partnership between fishermen, anglers and conservation organisations sought to increase knowledge of the species distribution, ecology, and reproductive biology. The capture of over 200 specimens was mapped and shrimps were examined and measured to determine their seabed substrate preferences, breeding condition and evidence of recruitment. Using a combination of SCUBA, towed video sled, beam trawl, oyster dredge and Van Veen grab, surveys were conducted to attempt to locate burrows and characterise the species habitat and associated fauna and flora, the results of which are appended. Records of shrimps captured combined with more recent observations 2007-2021 show the species to be widespread in the eastern Solent with a preference for sandy-mud substrate yet were also recorded on firmer ground in the west and south-west of the Isle of Wight. The number of females observed with mature ovaries and cement glands increased between October and April and individuals kept in aquaria were observed brooding eggs in March and April. Length measurements showed evidence of recruitment and establishment in the region. The species is a ‘flagship’ for the Solent benthos and the importance of local populations has been recognised by its inclusion in the Isle of Wight Biodiversity Action Plan (BAP).