SCDNR MISSION STATEMENT “To serve as the principal advocate for and steward of South Carolina’s natural resources” South Carolina - 1895
Why is the population important ?
•1942 – Santee- Cooper impounded •1957 – first documentation of fresh water spawning (Congaree River) •1960 – nationally recognized fishery • 1963 – aquaculture technique developed •1972 – official fish of South Carolina Why is the population important ?
•Freshwater fishing accounts for an economic effect in SC of 1.235 billion dollars (2006)
•Striped bass had the highest value among freshwater fishes – 277 million dollars What is the current status of the Santee-Cooper striped bass population?
State management plan (1996) – Goal #1 • “Manage naturally reproducing populations with strategies that optimize harvest and maximizing the possibility of conserving self-sustaining populations.” Natural reproduction
Egg studies – 1983 - 1992 Egg production
• 10 to 22 billion/year, 1988 – 1990 •“buy lots of lottery tickets” strategy • 82% from Congaree River Temperature and spawning • Rising temperatures induce spawning • Falling temperatures halt spawning
What are the seasonal movements? 250 Fish 3517
200 Sal-Broad Confluence Saluda River Watere River
Congaree River Cooper River 150 Lake Marion Santee River Lake Moultrie Broad River Cong-Wat Confluence 100
50
System KM System Diversion Canal
Pinopolis Dam 0
-50
250 Fish 3508 Sal-Broad Confluence 200
150 Cong-Wat Confluence 100
50 Diversion Canal System KM System
Pinopolis Dam 0
-50
4/1/06 8/1/06 12/1/06 4/1/07 8/1/07 Date How does stocking affect population size?
•Began stocking in 1984 • Currently stocking an average of 2.4 million/year • Stocked fish approximately 55% of population
300 Stocked 250 Wild
200
150
100Number
50
0 89 90 91 92 93 98 99 0 Year class What is current status of population? Current status of population
N of Age-1+ N of Age-4+ 300
250
200
150
100
50
0 1992 1994 1996 1998 2000 2002 2004 2006 2008 When will know when the population is fixed?
•When the public is happy •Santee-Cooper stakeholders
•When meet biological criteria – for example: •When 5 year average age-1+ index is ‘XXX’, and •When 5 year average age-4+ index is ‘YYY’ Why the suggested spawning flows?
300
250
200 striped bass striped - 1+ 150 age of 100
50 Abundance
0 0 10,000 20,000 30,000 Average April discharge (cfs) Minimizing sudden temperature changes
25
20
15 Broad
10 Sal Cola
Sal Dam
Average daily Temperature Average 5
0 0 20 40 60 80 100
Date - where '1' is March 1 and '92' is May 31. Spawning flows – April 1 – May 10
10000 Broad R. flow 9000 Lower Saluda 8000 flow Congaree R. flow 7000
6000
Flow, cfs 5000
4000
3000
2000
1000
0 0 10 20 30 40 50 60 ‘Matching’ Broad River inflow •Lower Saluda River flow is 45% of Broad River flow
•Matching will: •Augment Congaree flows during critical period • commensurate with available water flow •Minimize sudden temperature changes
•Over and above prescribed minimum flow, spawning flows will, on average: •Lower Lake Murray elevation by : •2.4” on June 1 •1.2” on August 1 What are the current studies and what do they hope to answer? Current and future cooperators?
Santee- Cooper striped bass stakeholder group
• representative from each Legislative district •About 40 members • guides, landing operators, academics, tourism, utility, fishing clubs, citizens •Effort began in 2006 • Several meetings each year Santee-Cooper Comprehensive Study Group
• Committee of 6 DNR biologists; started 2007
•Short-term goal • “Examine the magnitude of interspecific competition during the recruitment phase of key fish species”
•Long-term goal • “Define the energy partitioning and biological production within the key biotic components”
• Plans call for including outside members What is the growth rate and condition of juvenile striped bass and other key species?
160 2008 - Marion STB 2009 - Marion STB
140
120
TL (mm) 100
80
60 22 24 26 28 30 32 34 36 Week Number
Station SC-015 Averages and standard errors 40 for years with 8 or more monthly samples
g/liter) 30 µ
20 Chlorophyll a ( a Chlorophyll
10
0 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 What is the status and importance of the benthic community?
• Upper Lake Marion dominated by Asiatic clam (Corbicula)
• Densities capable of filtering twice the average volume of lake water in a single day
• Santee-Cooper - cooperator 1° producer 1° consumer 2° consumer 3° consumer
Simplified food web for Lake Marion REVISED Birds
Nutrients (and sunlight) Zooplankton
SHAD and other small Phytoplankton Mayflies, pelagic species other insects L J Adult Epiphyton * Molluscs STRIPED BASS and other large pelagic species
Aquatic plants L J Adult
* CATFISH and other Detritus large littoral species Terrestrial plants People * STOCKED What factors may impact the striped bass population?
•Aging of reservoir •Changes in hydrology and nutrient load •Invasive species •Clams and snails •Fishes, such as white perch •Anadromous fish passage rates •Stocking rates •Timing and magnitude of egg production •Man •Harvest/overfishing What recent regulatory reforms for striped bass have occurred in Santee-Cooper?
•1984 - 10/day, 18” minimum length
•1989 - 5/day, 18” minimum length
•1994 - 5/day, 21” minimum length
•2010 – (by stakeholders) • 3/day, 26” minimum length • season closed, June 1 – September 30 What studies are planned to validate the effects of the striped bass spawning flows?
• Temperature monitoring during spawning season
• No egg studies
• Continued evaluation of stocking
• Continued gill net monitoring
•Continuation of Santee- Cooper Comprehensive study Striped bass spawning flows should benefit other migratory spawners!
American shad Shorthead redhorse
Shortnose sturgeon Robust redhorse