Event Title
Invasive water hyacinth increases blue crab abundance and alters fish predation risk along marsh edges
Document Type
PowerPoint Presentation
Location
University Hall, Rm 134
Start Date
13-2-2020 10:15 AM
Description
Water hyacinth (Eichhornia crassipes) is an invasive floating freshwater plant that affects
water quality, increases habitat complexity, and alters aquatic invertebrate abundance and diversity. Hyacinth can also enter estuarine habitats in periods of high water runoff where it can colonize marsh edges and may impact the abundance and distribution of estuarine species. To examine how water hyacinth impacts estuarine marsh fauna, we examined the effects of water hyacinth on nekton communities and fish predation risk using trapping and tethering techniques along a marsh edge that had been recently colonized by water hyacinth. We placed chevron traps under water hyacinth and in open water habitats to examine how water hyacinth impacted macrofaunal abundance and diversity. We also examined how water hyacinth impacted predation risk by tethering minnows at increasing distances from the marsh edge in open water and water hyacinth. We found that shrimp, topminnows, and blue crabs were generally more abundant under water hyacinth. Blue crab abundance under hyacinth also decreased over time as the plant dispersed. In tethering studies, minnow survival was lower at the marsh edge under the hyacinth. Minnow survival also increased as the habitat shifted from water hyacinth to open water. Our results indicate that water hyacinth alters marsh edge habitats by increasing blue crab abundance, ultimately increasing their encounter rates with fish prey. In Louisiana, increasing tropical storms and freshwater diversions will likely increase the abundance of water hyacinth in marshes and increase the importance of blue crab predation and scavenging along marsh edges.
Recommended Citation
Hutton, Brittany; Steffins, Katheryn; Reiucau, Guillaume; and Hill, Jennifer, "Invasive water hyacinth increases blue crab abundance and alters fish predation risk along marsh edges" (2020). Undergraduate Research Symposium. 6.
https://digitalcommons.latech.edu/undergraduate-research-symposium/2020/oral-presentations/6
Invasive water hyacinth increases blue crab abundance and alters fish predation risk along marsh edges
University Hall, Rm 134
Water hyacinth (Eichhornia crassipes) is an invasive floating freshwater plant that affects
water quality, increases habitat complexity, and alters aquatic invertebrate abundance and diversity. Hyacinth can also enter estuarine habitats in periods of high water runoff where it can colonize marsh edges and may impact the abundance and distribution of estuarine species. To examine how water hyacinth impacts estuarine marsh fauna, we examined the effects of water hyacinth on nekton communities and fish predation risk using trapping and tethering techniques along a marsh edge that had been recently colonized by water hyacinth. We placed chevron traps under water hyacinth and in open water habitats to examine how water hyacinth impacted macrofaunal abundance and diversity. We also examined how water hyacinth impacted predation risk by tethering minnows at increasing distances from the marsh edge in open water and water hyacinth. We found that shrimp, topminnows, and blue crabs were generally more abundant under water hyacinth. Blue crab abundance under hyacinth also decreased over time as the plant dispersed. In tethering studies, minnow survival was lower at the marsh edge under the hyacinth. Minnow survival also increased as the habitat shifted from water hyacinth to open water. Our results indicate that water hyacinth alters marsh edge habitats by increasing blue crab abundance, ultimately increasing their encounter rates with fish prey. In Louisiana, increasing tropical storms and freshwater diversions will likely increase the abundance of water hyacinth in marshes and increase the importance of blue crab predation and scavenging along marsh edges.