July 2004 Long Bay Hypoxia Event

Flounder Catches Water Quality SCDNR CCU Temperature/Wind/Current Potential Hypotheses Other Areas Experiencing Hypoxia Outline

Garden City Surfside Beach Myrtle Beach SP Springmaid Second Ave Apache Cherry Grove Abnormal Flounder Catches July 2004 Long Bay

7/15 – lethargic flounder in surf 7/16 – some lethargic flounder in surf 7/16 – flounder catches started 7/17-18 – flounder catches in surf Reports of shark disappearing - three wks 7/21 – dead fish 7/21 – some flounder started being caught No unusual flounder catches 7/20 – murky water Fewer sharks and more guitar fish 7/23 – flounder catches still high Garden City Surfside Beach Myrtle Beach SP Second Ave Springmaid Apache Cherry Grove

Flounder Catch Reasons A broad scale, and persistent low oxygen event in near shore waters could be a possible driving mechanism for both the lethargic flounder off Pawleys Island and the atypical flounder behavior in the vicinity of the fishing piers along about 10 miles of the Grand Strand.

G M U A 2 S C SCDNR July 23, 2004 Average DO Hypoxia = DO < 2 mg/l Anoxia = DO close to 0

CCU Second Ave. and Springmaid Piers July 20, 2004 Dissolved OxygenTemperature Temp ( o C) Depth (m) DO (ppm) Depth (m) Second Ave. Springmaid

CCU Second Ave. and Springmaid Piers July 22, 2004 Dissolved OxygenTemperature Second Ave. Springmaid

CCU Cherry Grove and Apache Piers July 23, 2004 o Temp ( C) Depth (m) DO (ppm) Depth (m) Cherry Grove Apache TemperatureDissolved Oxygen

USC Temperature Anomalies in the SC Coastal Waters

Wind Conditions and Water TemperatureAlongshore Winds from the Southwest. - Persistent

Wind Conditions and Coastal Circulation Patterns in the Myrtle Beach Area Winds from the southwest: Upwelling event (onshore nearbed flows), I&III No upwelling event (case II), flows follow wind pattern

Hypotheses Nearshore hypoxia events in Long Bay are correlated with Gulf Stream intrusions, upwelling-favorable winds, and water column stratification During periods of locally heavy rainfall, nearshore hypoxia events in Long Bay are correlated with local stormwater discharges including beach pipes, ocean outfalls, swashes During periods of regionally heavy rainfall, nearshore hypoxia events in Long Bay are correlated with discharges from local estuaries

Other Areas Experiencing Hypoxia Events Gulf of Mexico Mississippi River Discharge Freshwater and nutrients Hood Canal in Puget Sound Heavy Stratification High nutrient inputs New Jersey/New York Hudson River discharge Algal Blooms