Paulinus Chigbu

First record of Ianiropsis cf. serricaudis in Maryland Coastal Bays, USA (Crustacea, Peracarida, Janiridae)

Abstract During monthly sampling of benthic invertebrates at 13 stations in the Maryland Coastal Bays (MCBs) from March to December 2012, a total of 29 individuals of Ianiropsis cf. serricaudis were collected. This species is being reported for the first time in MCBs. A detailed illustration and description of an adult male of I. cf. serricaudis from MCBs is presented. An illustrated key of males of Ianiropsis species belonging to the palpalis-group is also presented. The size of the largest male was 3.0 mm and that of the largest female was 2.5 mm. It is possible that I. cf. serricaudis was present in the MCBs, but overlooked during previous surveys of marine benthic invertebrates in the area because of its small body size and lack of taxonomic expertise.

Mysid shrimp dynamics in relation to abiotic and biotic factors in the coastal lagoons of Maryland, Mid-West Atlantic, USA

ABSTRACT The distribution and densities of two mysid species, Neomysis americana and Americamysis bahia in the coastal lagoons of Maryland were investigated using data collected monthly from March 2012 to December 2013. Mysid density was higher in the northern than southern bays in 2013 for Americamysis (P = 0.043) and Neomysis (P = 0.004). Neomysis americana density was inversely correlated with temperature (P < 0.00001) and salinity (P < 0.01), but positively correlated with water depth in 2012 (P < 0.01). In the spring, total mysid and Neomysis densities (nos. m−2 ± S.E) were negatively related to the catch-per-unit effort (CPUE ± S.E) of fish predators (r = −0.40, −0.81; P = 0.051, 0.002, respectively). Mysid density was higher in winter (March, 1.3 ± 0.8 and spring, May, 1.4 ± 1.3) 2012, when the CPUE of bay anchovy (Anchoa mitchilli) was relatively low (April: 5.8 ± 2.3; and May: 11.9 ± 4.5, 2012), than during summer (August, 0.003 ± 0.002 nos. m−2), when fish CPUE was relatively high (191.7 ± 66.5). The observed seasonal patterns of mysid and fish densities, supported by the fact that mysids comprise 53–97% by weight of the diet of some of the abundant fish species in the bays, suggests a top-down control of mysids by fish predation. However, summer high temperatures in the bays exceeded 22°C, at which juveniles of N. americana have been reported to suffer high mortality, and perhaps contributed to the lower density of mysids in the summer.