EL monitoring program provides valuable insights for disparaged fish

Published Dec. 2, 2013
EL’s Steven George (left front), field zoologist, and Bradley Lewis (right front), research technician, carry an adult Gulf sturgeon from the boat driven by Dr. Todd Slack to a live well for processing.

EL’s Steven George (left front), field zoologist, and Bradley Lewis (right front), research technician, carry an adult Gulf sturgeon from the boat driven by Dr. Todd Slack to a live well for processing.

Unattractive, sometimes a nuisance and once considered uneatable, the Gulf sturgeon gained new respect in 1991 following its listing as an endangered species, and will benefit from the U. S. Army Engineer Research and Development Center’s (ERDC) Environmental Laboratory (EL) monitoring program now under way on the Pearl and Pascagoula rivers and waters around the Mississippi Gulf’s Ship Island.

Led by Todd Slack, research fisheries biologist, this project featured a webinar in July for representatives from the Mississippi Coastal Improvement Program (MsCIP), the U. S. Army Corps of Engineers (USACE) Mobile District and others interested in the current findings on Gulf sturgeon monitoring as well as future research directions related to the monitoring program.

Slack is assisted by Mark Peterson with the University of Southern Mississippi Gulf Coast Research Laboratory.

“The teleconference was opened to other state and federal agencies including the U.S. Fish and Wildlife Service (USFWS), U.S. Geological Survey, USACE and several ERDC researchers who are participating in some aspect of the MsCIP project on Ship Island,” Slack said.

Slack calls on his 11 years experience as the state ichthyologist with the Mississippi Department of Wildlife, Fisheries and Parks at Jackson’s Natural Science Museum before joining EL’s Fish Ecology Team in April 2009. His research interests include sturgeon life history and behavior, distribution and biology of southeastern fishes and freshwater mussels.

Gulf sturgeon occur in Gulf of Mexico drainages from Tampa Bay westward to the Mississippi River.  Known as some of the oldest living fish, they can reach several hundred pounds and live up to 60 years.  Gulf sturgeon exhibit a unique life history approach, with adults migrating to upriver reaches to spawn during the spring and then migrating back to saltwater environments during late fall. 

Following the spring spawning event, migrating fish congregate in deep water areas in lower reaches of their respective river where they remain throughout the summer months.  During this “staging” or “holding” period, the sturgeon are generally inactive and do not feed, which causes them to be easily stressed by major changes in water quality conditions.

This subspecies of Atlantic sturgeon is now listed as threatened under the Endangered Species Act by the USFWS and was cited as endangered in Mississippi in 2001. Population declines are attributed to commercial fishing, dam construction and general water quality deterioration as reported in 1995 by USFWS and the Gulf States Marine Fisheries Commission.  In Mississippi, the Gulf sturgeon historically occurred in the Pascagoula, Pearl and Mississippi rivers, with current populations occurring only in the Pearl and Pascagoula rivers.

“Critical habitat for Gulf sturgeon was designated in 2003, including the shoreline areas of the Mississippi Sound barrier islands of Cat, Ship, Horn and Petit Bois,” Slack said.  “Several studies noted the presence of Gulf sturgeon in these barrier island passageways during winter months, presumably to feed before returning to riverine habitats in spring and summer.” .

                                             Project objective to document habitat use

Following Hurricanes Cindy, Katrina and Rita, the MsCIP and Louisiana Coastal Protection and Restoration (LaCPR) were authorized by Congress to develop strategic plans to reduce future storm damage, saltwater intrusion and shoreline erosion while promoting fish and wildlife preservation. 

One component of MsCIP’s plan evaluated comprehensive barrier islands’ restoration, including filling the “Camille Cut” on Ship Island.  In 2009, USACE determined returning it to a pre-Hurricane Camille state would allow low-lying areas further protection from storm surges.

 “The main objective of our current project is to conduct a multi-year monitoring program to establish comparative habitat utilization of the passes on Ship Island by Gulf sturgeon,” Slack said.

                                                Construction effects on sturgeon

He explained that “our approach is to assess habitat utilization at both ends of Ship Island and at the Camille Cut by monitoring acoustically tagged Gulf sturgeon before construction, as our baseline assessment, during the construction phase and after filling the cut.”  

“The team will evaluate telemetry activity patterns at two different levels, a coarse scale assessment to determine the relative occurrence of Gulf sturgeon within the project area and a fine scale assessment to address what Gulf sturgeon are doing within the identified areas.

“The resulting data from these two approaches will allow project managers to better evaluate the uniqueness of these specific habitats to Gulf sturgeon.  Specifically, whether filling Camille Cut and reducing the barrier island pass habitat will or will not have an impact on Gulf sturgeon populations,” Slack said of the monitoring program. 

                                                     Initial monitoring results

The July briefing also provided Mobile District with an overview of the 2012-13 telemetry deployment at Ship Island.

“This was the third deployment period for the baseline assessment of Gulf sturgeon activity.   During this September 2012 to June 2013 monitoring, we had 29 telemetry receivers deployed along Ship Island and Dog Keys Pass, which extends from E Ship Island to Horn Island.  We recorded more than 94,000 detections and detected 21 telemetry tagged Gulf sturgeon within the telemetry array representing seven river systems,” Slack said.

He said the telemetry array was redeployed in September 2013 and included 38 total receivers. 

“This will be the last deployment period for baseline data.  We will be presenting another briefing summarizing our findings at the end of the current deployment period in July 2014,” Slack said of the project which focuses on EL’s efforts to maintain and increase habitats for identified endangered species.