Research ProjectNearshore Ecology of the Rhode River

Nearshore Survey: Shallow Water Ecology of the Rhode River

  • Seining at Fox Point in the Rhode River

    Seining at Fox Point in the Rhode River. Photo by Steve Sniteman

  • Tethered shrimp

    Shrimp have a small hook tied to them before they are placed in the water on tether lines.  Photo by Laura Patrick

  • Dip-net sweeps for shrimp are conducted by staff, interns and volunteers” by Stacey Havard

    Dip-net sweeps for shrimp are conducted by staff, interns and volunteers.  Photo by Stacey Havard

Project Goal

We have been conducting annual surveys of the shallow water nearshore community of the Rhode River since 1991 to study predator-prey dynamics between native grass shrimp species and common fish and crab predators.

Description

The Nearshore Survey is a long-term research study (1991-present) examining the interactions between native grass shrimps (Palaemon pugio, P. mundonovus, and P. vulgaris) and their common predators in the Rhode River. Research is carried out at multiple locations within each of two sites in the Rhode River (Canning House Bay and Fox Point) every summer from June through August, using three methods: seining, dip-net sweeps and tethering.

Seine Survey - Our monthly seine net survey characterizes the presence and abundance of fish and crab predators in the nearshore zone (shallow waters where shrimp seek refuge from these predators). All fishes, crabs and any turtles are identified, measured, and returned to the water. 

Shrimp Tethering - Tethering involves placing shrimp tied to lines in 1 foot (30 cm) of water for several timed intervals and measuring relative predation. It allows us to examine the predator-prey interactions between the shrimp and their fish and crab predators. We use this information to assess the relative effectiveness of the nearshore zone as refuge habitat.  

Dip-net Sweeps - Grass shrimp distribution and relative abundance is monitored monthly at permanent ten-meter-long transects at each site by pushing a long handled dip net along the river bottom. Shrimp are collected, identified, measured, examined for parasites and reproductive state, and returned to the river. These data allow us to quantify the fluctuations in grass shrimp parasite load and population dynamics.

This project involves volunteers. If you are interested, please contact Stacey Havard or Alison Cawood.

Contact

Stacey Havard
(443) 482-2486
Havards@si.edu

Clark, Kelton L., Ruiz, Gregory M. and Hines, Anson H. 2003. Diel variation in predator abundance, predation risk and prey distribution in shallow-water estuarine habitats. Journal of Experimental Marine Biology and Ecology, 287: 37-55.

Dittel, Ana I., Hines, Anson H., Ruiz, Gregory M. and Ruffin, K. Keith. 1995. Effects of shallow water refuge on behavior and density-dependent mortality of juvenile blue crabs in Chesapeake Bay. Bulletin of Marine Science, 57(3): 902-91

Hines, Anson H. and Ruiz, Gregory M. 1995. Temporal variation in juvenile blue crab mortality: Nearshore shallows and cannibalism in Chesapeake Bay. Bulletin of Marine Science, 57(3): 884-901.

Everett, Richard A. and Ruiz, Gregory M. 1993. Coarse woody debris as a refuge from predation in aquatic communities: an experimental test. Oecologia, 93: 475-486.

Ruiz, Gregory M., Hines, Anson H. and Posey, Martin H. 1993. Shallow water as a refuge habitat for fish and crustaceans in non-vegetated estuaries: an example from Chesapeake Bay. Marine Ecology Progress Series, 99: 1-16.