04-12-2011, 11:10 AM
Brunswick, GA -For a second straight winter, lower-than-normal temperatures came to coastal Georgia driving down estuarine water temperatures to the lethal level for some marine organisms. The Georgia Department of Natural Resources (DNR) and many anglers are concerned about the status of species that support the state's valuable commercial and recreational saltwater fishing activities.
"Water temperatures in the mid to low 40s are lethal to over-wintering white shrimp and some fish species, such as spotted seatrout. We documented such water temperatures during a mid-December cold snap, again in late December, and on some occasions in January," explained Spud Woodward, director of the Coastal Resources Division of DNR.
In early December 2010, the coast-wide catch of white shrimp in the DNR trawl surveys was 11 % above the long-term average. In mid-December, a cold snap caused the water temperatures in tidal rivers and creeks to plummet from the mid-50s to the low-40s in just a few days. Coastal Georgia continued to experience abnormally cold temperatures throughout December and into January 2011. By February, the coast-wide catch of white shrimp was 95% below the long-term average, and this trend continued in March with catches still 92% below average.
"The South Carolina Department of Natural Resources also documented very low shrimp abundance in their tidal rivers and creeks, and requested NOAA Fisheries to close federal waters off their state to shrimp trawling for April until early June. Georgia DNR did not make a similar request, but we'll likely delay the opening of state waters to food shrimp harvest so we allow more of the shrimp that survived the winter to spawn before being caught," stated Patrick Geer, chief of marine fisheries for DNR.
Angler reports and observation by state natural resource agency staff indicate that seatrout populations in the Carolinas and Georgia also suffered from the cold winter. The North Carolina Division of Marine Fisheries, in an unprecedented action, prohibited the harvest of spotted seatrout in mid-January as a measure to conserve their surviving fish. DNR is also concerned about the status of our seatrout populations, but won't know the extent of the impacts until the Marine Sportfish Population Health Survey resumes this summer. However, based on the reports of fish kills from Savannah to St. Simons Island, DNR is partnering with the Coastal Conservation Association - Georgia to encourage the voluntary release of larger spotted seatrout through Operation ROE (Release Over Eighteen).
DNR studies show that approximately 94 percent of trout more than 18 inches in length are females, so it is not surprising that many anglers refer to all larger fish as roe (egg) trout. Research has shown that larger, older females produce many more eggs than smaller individuals. An 18-inch female seatrout has the potential to produce almost 18 million eggs during the six-month spawning season - almost five times the egg production of a 14-inch trout. Plus, older fish have survival traits valuable in the gene pool.
"The voluntary release of larger trout is a great way for the average angler to directly participate in conservation while helping ensure there'll be more fish to catch in the future. We started Operation ROE when we realized the winter of 2009/2010 had adversely impacted our seatrout populations. We had a good response from the fishing community, and fortunately DNR surveys showed that our seatrout population fared better than we expected. However, the cold weather came earlier this winter, and the impacts to Georgia's fish populations may actually have been worse. I hope that anglers will once again do their part to help our seatrout population rebound from this winter," said John Duren, state chairman of CCA Georgia.
OPERATION ROE
Fact sheet
"¢ Published research indicates that water temperatures below 44 degrees can be lethal to spotted seatrout. Even when trout are not killed immediately, they can suffer stress leading to chronic mortality.
"¢ Spotted seatrout exhibit sexual dimorphism - females are larger than males at the same age. In Georgia, the majority of fish larger than 18 inches are female.
"¢ Spotted seatrout are indeterminate batch spawners - an individual fish will spawn multiple times during the spawning season (April to September). Research has shown that spawning may occur two to four times each month with larger and older fish spawning more frequently than younger fish.
"¢ The number of eggs released per spawning event is positively related to the size of the female - the larger the fish, the more eggs released.
Age<br />
Total Length (inches)<br />
Eggs Per Spawn<br />
Annual Egg Production
1<br />
11<br />
175,000<br />
3.2 million
2<br />
15<br />
407,000<br />
9.5 million
3<br />
18<br />
530,000<br />
17.6 million
"¢ Typically, Age 1 and 2 fish comprise the majority of Georgia's spotted seatrout population and produce most of the eggs during the annual spawning season. However, it's theorized that smaller, younger trout suffer disproportionately high mortality during cold winters. Thus, in the spawning season after a very cold winter, older and larger trout may contribute a greater portion of annual egg production than in years following mild winters.
"¢ The voluntary release of trout larger than 18 inches in length during the period from April through September 2011 should result in increased egg production during the 2011 spawning season and, with favorable conditions for survival, a stronger year class of juvenile trout going into the winter of 2011/2012.
Media Contact<br />
Nancy Butler<br />
Communications Outreach<br />
GA DNR/Coastal Resources Division<br />
One Conservation Way<br />
Brunswick, GA 31520<br />
912.262.3140<br />
nancy.butler@dnr.state.ga.us
"Water temperatures in the mid to low 40s are lethal to over-wintering white shrimp and some fish species, such as spotted seatrout. We documented such water temperatures during a mid-December cold snap, again in late December, and on some occasions in January," explained Spud Woodward, director of the Coastal Resources Division of DNR.
In early December 2010, the coast-wide catch of white shrimp in the DNR trawl surveys was 11 % above the long-term average. In mid-December, a cold snap caused the water temperatures in tidal rivers and creeks to plummet from the mid-50s to the low-40s in just a few days. Coastal Georgia continued to experience abnormally cold temperatures throughout December and into January 2011. By February, the coast-wide catch of white shrimp was 95% below the long-term average, and this trend continued in March with catches still 92% below average.
"The South Carolina Department of Natural Resources also documented very low shrimp abundance in their tidal rivers and creeks, and requested NOAA Fisheries to close federal waters off their state to shrimp trawling for April until early June. Georgia DNR did not make a similar request, but we'll likely delay the opening of state waters to food shrimp harvest so we allow more of the shrimp that survived the winter to spawn before being caught," stated Patrick Geer, chief of marine fisheries for DNR.
Angler reports and observation by state natural resource agency staff indicate that seatrout populations in the Carolinas and Georgia also suffered from the cold winter. The North Carolina Division of Marine Fisheries, in an unprecedented action, prohibited the harvest of spotted seatrout in mid-January as a measure to conserve their surviving fish. DNR is also concerned about the status of our seatrout populations, but won't know the extent of the impacts until the Marine Sportfish Population Health Survey resumes this summer. However, based on the reports of fish kills from Savannah to St. Simons Island, DNR is partnering with the Coastal Conservation Association - Georgia to encourage the voluntary release of larger spotted seatrout through Operation ROE (Release Over Eighteen).
DNR studies show that approximately 94 percent of trout more than 18 inches in length are females, so it is not surprising that many anglers refer to all larger fish as roe (egg) trout. Research has shown that larger, older females produce many more eggs than smaller individuals. An 18-inch female seatrout has the potential to produce almost 18 million eggs during the six-month spawning season - almost five times the egg production of a 14-inch trout. Plus, older fish have survival traits valuable in the gene pool.
"The voluntary release of larger trout is a great way for the average angler to directly participate in conservation while helping ensure there'll be more fish to catch in the future. We started Operation ROE when we realized the winter of 2009/2010 had adversely impacted our seatrout populations. We had a good response from the fishing community, and fortunately DNR surveys showed that our seatrout population fared better than we expected. However, the cold weather came earlier this winter, and the impacts to Georgia's fish populations may actually have been worse. I hope that anglers will once again do their part to help our seatrout population rebound from this winter," said John Duren, state chairman of CCA Georgia.
OPERATION ROE
Fact sheet
"¢ Published research indicates that water temperatures below 44 degrees can be lethal to spotted seatrout. Even when trout are not killed immediately, they can suffer stress leading to chronic mortality.
"¢ Spotted seatrout exhibit sexual dimorphism - females are larger than males at the same age. In Georgia, the majority of fish larger than 18 inches are female.
"¢ Spotted seatrout are indeterminate batch spawners - an individual fish will spawn multiple times during the spawning season (April to September). Research has shown that spawning may occur two to four times each month with larger and older fish spawning more frequently than younger fish.
"¢ The number of eggs released per spawning event is positively related to the size of the female - the larger the fish, the more eggs released.
Age<br />
Total Length (inches)<br />
Eggs Per Spawn<br />
Annual Egg Production
1<br />
11<br />
175,000<br />
3.2 million
2<br />
15<br />
407,000<br />
9.5 million
3<br />
18<br />
530,000<br />
17.6 million
"¢ Typically, Age 1 and 2 fish comprise the majority of Georgia's spotted seatrout population and produce most of the eggs during the annual spawning season. However, it's theorized that smaller, younger trout suffer disproportionately high mortality during cold winters. Thus, in the spawning season after a very cold winter, older and larger trout may contribute a greater portion of annual egg production than in years following mild winters.
"¢ The voluntary release of trout larger than 18 inches in length during the period from April through September 2011 should result in increased egg production during the 2011 spawning season and, with favorable conditions for survival, a stronger year class of juvenile trout going into the winter of 2011/2012.
Media Contact<br />
Nancy Butler<br />
Communications Outreach<br />
GA DNR/Coastal Resources Division<br />
One Conservation Way<br />
Brunswick, GA 31520<br />
912.262.3140<br />
nancy.butler@dnr.state.ga.us