Alternate Title

Colonization of Artificial Substrates at Dauphin Island, Alabama: A Comparison of Balanus (Cirripedia), Membranipora tenuis (Bryozoa), and Conopeum tenuissimum (Bryozoa) Settlement in 1999-2000 and 2010-12


Glass slides were used as artificial substrates to collect settling bryozoan and barnacle larvae during two collection periods, in 1999–2000 and 2010–12. This study follows up a previous report of Balanus settlement in Mobile Bay and now includes two bryozoan species. Slides were immersed at the Dauphin Island Sea Lab (Alabama) for 1 wk each month for 17–18 mo in each study, and then collected for staining and counting. The bryozoans Conopeum tenuissimum and Membranipora tenuis were both present in 1999–2000, though in 2010–12 C. tenuissimum was rarer and only six organisms were observed. In general the bryozoan colonization period extended throughout the spring, summer, and fall, with peak settlement in May–Aug. Barnacle cyprids and metamorphed stages colonized the substrates in July–Sept. and Feb.– March in 1999–2000, but in 2010–12 they were present in the summer and fall months and did not have a Feb.–March settlement. Colonization by both bryozoans and barnacles correlated statistically with temperature, and M. tenuis correlated negatively with salinity as its colonization density increased following the decreased salinity in the spring. In 1999–2000 only M. tenuis correlated with temperature. This study reports settlement periods for these invertebrates in Alabama and provides new data for colonization studies in Mobile Bay. Additionally, we document the successful colonization of substrates by these invertebrates immediately following the Deepwater Horizon oil spill.