SEG Striped Bass & Fisheries and Aquatic Resources Committee Meeting Summary

Members Present:

AGENDA

Striped Bass Committee -

(1)Ed's striped bass modeling document
(II) The COEs report:  ACurrent Status of Information on Striped Bass in the Savannah River Estuary
(III) Spring 2002 striped bass sampling update and the direction for future studies and monitoring

Fisheries and Aquatic Resources Committee -
(2) Status of current studies
(3) Assessment of impacts on target species groups through ATM=s model (e.g., white & brown shrimp, spotted seatrout & red drum, shortnose and Atlantic sturgeon, and shad)
(4) Fisheries workshop meeting

Striped Bass Committee

(I) Ed's striped bass modeling document

Listed below are main items that were discussed. Ed and Ted will revisit these items and submit a final draft for review.

Although the document contains four main categories (spawning, egg development, larval development, and egg and larval transport), the general consensus was there is some overlap between categories and that model runs could be formatted to meet the committee's needs.

A. Spawning:

1) Discussion began asking for input on the value of velocity as an environmental cue for striped bass spawning. The value was suggested as important, but given the variability of velocity in the Savannah River Estuary (i.e., different discharges and tidal influences) it would be difficult to suggest one key velocity and then expect meaningful data from the model results. A literature search will be conducted to see if an actual spawning velocities would be meaningful. Also, John Robinette will talk to Tennessee biologist who are conducting research on spawning striped bass in circular tanks.

2) Without velocity, evaluation criteria would be based on reaches of the Savannah River Estuary containing 90th percentile salinities = 1 ppt. Bo Ellis then brought up the point the 90th percentile salinities may be to conservative given the pass or fail mode of the model. After discussions, Tom and Ed suggested using a weighted average (e.g.,90th percentile salinity output receiving a value of 1.0 and the 75th percentile salinity receiving a value of 0.5). This additional output will be considered for the next draft report.

3) Mean and low river discharge are currently proposed for the model runs. Ted suggested that we may want to include a high flow. After discussions, it was concluded to look at gauge data at Clyo from mid-March through the 1st of May (1953 to present) and use a 20th, 50th, and 80th percentile flows for model runs.

B. Egg Development:

1) The committee discussed the evaluation criteria of the mean 50th percentile salinity = 9 ppt. Is this value to liberal or should we consider a more conservative measure (i.e., mean of 90th percentile salinity)?

2) Again, It was suggested to use 20th, 50th, and 80th percentiles mid-March through the 1st of May flows for model runs.

C. Larval Development:

1) The committee discussed the criteria of the mean 50th percentile salinity ranging from 3-9 ppt. Is mean 50th percentile salinity = 9 ppt suitable for the model. Again, do we want to take the mean of the 50th percentile salinity or the 90th percentile salinity?

2) Ted indicated that some past research has shown 1-2 day old striped bass larvae as being the most susceptible to increased salinities. Given this fact, should the model flow data reflect the peak spawning period (Mid-march through the 1st of May). Ed pointed out that there may be dissolved oxygen (D.O.) problems during end of May and June and wanted to include May-June flows and D.O.'s in the model. It was then suggested that we use two different flow regimes.

3) Bo pointed out that we need to be aware of temperature outputs when we are obtaining D.O. readings for the proposed time periods that we want the model runs to encompass. Ed and Tom suggested weekly or daily water temperature outputs need to be considered in the model to correct D.O. readings. Also, use two periods: (1) 15 March - 30 April and (2) 1 May - 1 June.

4) Again, for whatever time periods we consider to run the model, use 20th, 50th, 80th percentiles for discharge.

D. Egg and Larval Transport

Questions were raised concerning how the model would predict egg transport. Discussion was brought up about how the egg would drift within the model (i.e., would a drift rate of 64% of the average current velocity be used or not), and can the model could approximate the actual drift (throughout the water column) of striped bass eggs. It was suggested not to use the 64% average velocity, since the model calculates flow rates for each grid separately. This calculation has the flows being faster in some cells than others, accomplishing much the same thing as applying the 64% figure to a cross-sectional average velocity. A decisions on the validity and usefulness of this data will be considered.

(II) USCOE's report ACurrent Status of Information on Striped Bass in the Savannah River Estuary@

The report was well prepared and received. Further peer review is needed. Individuals with knowledge of striped bass biology in coastal rivers comments will on potential data gaps that may have missed or overlooked. Matt Thomas has agreed to comment and Terry Stratton will call other state fishery biologist.

(III) Spring 2002 striped bass sampling update and the direction for future studies and monitoring

1) Ted gave a sampling update from the Savannah River. Fewer large (= 9 kg) striped bass were collected this year. Two main factors likely contributed to this decrease in catch: 1) low flows and increased water temperatures likely cued large fish to migrate further north beyond the standardized sampling area, and 2) increased salinities prohibited eletrofishing in the lower reaches of the estuary during late-February and early March.

2) One day of electrofishing trip was conducted above Hwy. 301 (about RM 130-150). In 2.85 pedal hours, four large (>9 kg) female striped bass were collected. Two of the fish were spent and two fish were gravid.

3) The significance of spawning in the upper Savannah River is unknown and if spawning is related to river discharge (with low discharges correlated with increased salinities and higher water temperatures).

4) No data has been collected on striped bass recruitment in the upper reaches of the Savannah River. GADNR will conduct night shocking survey to assess recruitment of juvenile striped bass during July-September.

5) GADNR will be monitoring thermal refuge above and below the New Savannah Bluff Lock and Dam.

6) Ted mentioned that spatial striped bass egg and larvae collections at the historic sampling areas combined with sampling in the upper reaches (RM 60-180) would be beneficial information. Perhaps under normal flow years there would be the appropriate environmental cues favoring the upper Back River for striped bass spawning habitat. Further, under low, normal, or high flows what is the contribution of striped bass spawning in the upper reaches (RM 60-180).

7) Richard Weyers mentioned that Georgia Cooperative Fish and Wildlife Research Unit (GACOOP) collected about 40 striped bass larvae in mid-March of 2002. The larvae were collected on the Front River at RM 26. Collecting this many striped bass larvae was surprising for three reasons. First, studies in 1999 and 2000 resulted in no larval striped bass collected. Secondly, the amount of sampling effort in past studies (7 days a week from mid-March through May) was much more extensive than the present study (4 sample periods in one month). Finally, collecting larvae in mid-March is early into the spawning season (spawning peak is generally in mid-April).

Fisheries and Aquatic Resource Committee

(I) Status of Current Studies

Bill Post gave an sampling update for SCDNR. Everything is going well, an annual report should be posted on the web site soon and the final report should be completed by December 2002. Richard Weyers gave an update for GACOOP. Mentioned that their annual report is posted on the web site, gave brief description of sampling efforts and number of species collected, and the final report should be available by December 2002.

(II) Assessment of impacts on target species groups through ATM's model (e.g., white & brown shrimp, spotted seatrout & red drum, shortnose and Atlantic sturgeon, and shad)

Ted began discussions by reading Prescott Brownells (NMFS) email regarding this assessment. Prescott suggested in the email that Awe consider using a small (3-5) selection of estuarine and freshwater species models as an >extension' of ATM's hydrodynamic model. Using a team approach we can easily adjust the species models to more accurately reflect Savannah River conditions.

A listing of models (and species profiles)is available from the USGS National Wetlands Research Center at the following link:

http://www.nwrc.usgs.gov/diglib.htm

We should be able to use selected models plus outputs from the ATM hydrodynamic model with GIS to identify and display changes in suitable habitat area and location from historic conditions, present conditions, and forecast changes with project alternatives and mitigation alternatives.

After much discussion it was decided that the first step was to identify species of concern. John Pafford and Patrick Geer would review GACOOP's annual report and then provide feedback on any saltwater/estuarine species that they may need further consideration. It was decided that a process of soliciting volunteers to look at literature (Habitat Suitability Indices and Specie Profiles) for the identified species of concern should begin. One committee member would pick one fish species and then provide feedback to committee on potential impacts. Mark Collins was volunteered for shortnose and Atlantic sturgeon and Patrick Geer volunteered for white and brown shrimp.

(III) Fisheries workshop meeting

The committee agreed that the final reports from SCDNR and GACOOP need to completed and reviewed before holding the workshop. If reports are completed by December 2002, the suggested time to hold the fisheries workshop was February 2003.