Established populations of Paracerceis sculpta (Isopoda) in the Northern Gulf of Mexico

A population of the isopod Paracerceis sculpta Holmes, 1904 was found in Port Aransas, Texas in Northern Gulf of Mexico in 2009, the first report of the species in the Gulf of Mexico. The last large isopod survey in the area was conducted in 1981 implying that P. sculpta invaded some time in the last 28 years. Here, we show size frequency distributions of 858 individuals, alpha males (mean length = 5.48 mm ± 0.09 SE), pre-alpha males (3.94 mm ± 0.15), females (2.76 mm ± 0.03) and juveniles (1.24 mm ± 0.02). Beta and gamma males are absent in Texas, a major contrasting difference between the invasive and native populations.