Settlement patterns of brachyuran megalopae in a Louisiana estuary |
| |
| Authors: | Barbara E Hasek Nancy N Rabalais |
| |
| Institution: | 1. Department of Biology, University of Louisiana, 70504, Lafayette, Louisiana
2. Louisiana Universities Marine Consortium, 8124 Highway 56, 70344, Chauvin, Louisiana
|
| |
| Abstract: | Artificial substrate collectors were used to sample settled brachyuran megalopae in Terrebonne Bay, Louisiana, northern Gulf
of Mexico. Three taxa,Callinectes sapidus, Uca spp., andRhithropanopeus harrisii, were the most common settlers. Settlement occurred almost year-round, although settlement densities were highest in late
summer and early fall. In 1990, all three taxa had several simultaneous settlement peaks; in 1991, one simultaneous settlement
peak occurred. FewerC. sapidus andUca spp. settled in 1991 than in 1990, but settlement abundance ofR. harrissii was similar between years. Local weather events, such as heavy precipitation, may have influenced the lower abundances ofC. sapidus andUca spp. in 1991. The megalopae ofC. sapidus andUca spp., which re-invade the estuary from higher salinity offshore waters where larval development occurs, may have been more
affected by the lower 1991 estuarine salinity values than the larvae ofR. harrissii, which are retained within the estuary throughout larval development. Settlement ofC. sapidus andUca spp. was correlated with maximum tidal height, tidal amplitude, salinity, temperature, and lunar phase. In 1990, settlement
ofC. sapidus was correlated with lunar declination cycles; settlement peaks occurred during equatorial minimum amplitude tides. The settlement
ofR. harrisii was associated with tidal amplitude and lunar phase. Associations between environmental variables and settlement of megalopae
were not consistent between the two years sampled. The opposing or reinforcing effects of various environmental variables
on settlement, e.g., tidal height and rainfall, are superimposed on long-term hydrologic cycles so that dramatically altered
cycles of settlement occur among years. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
