Signaling the Return of 



By Odile Fredericks 



ibout mid-March along North 

 Carolina's seaside shorelines, coastal 

 waters begin to warm, plants spurt new 

 growth, critters emerge from their 

 winter dormancy, baby animals are 

 born. A timeless cycle of renewal, birth 

 and the perpetuation of life is repeated. 



The warmth of the salty shallows 

 stimulates the plankton to bloom, the 

 first seed in the marine food chain, 

 while brightening skies and longer days 

 trigger reproductive hormones in sea 

 creatures offshore. By March, waves of 

 sea babies, such as brown shrimp, 

 flounder and spot larvae, move with the 

 tides and the currents into the estuaries. 

 Near coastal inlets, rising spring 

 temperatures awaken the blue crabs. 



Shoreside, ospreys migrating from 

 the tropics return to nests perched high 

 atop telephone poles and channel 

 markers. Gulls and terns make nests 

 along deserted inlet shorelines and 

 dredge-spoil islands. Black bears 

 venture out with their winter-born cubs 

 to forage for food while red wolves lie 

 pregnant in their dens. Newborn river 

 otters rest with their mothers in hol- 

 lowed tree trunks. 



"Generally, spring is a season of 

 change and movement," says Lundie 

 Spence, North Carolina Sea Grant's 

 marine education specialist. "If you're a 

 cold-blooded animal, such as an oyster 

 or a crab, you didn't do much during the 

 winter. You are dormant and slow. With 

 warmth and more food, oysters, bar- 

 nacles and crabs have more energy for 

 reproduction. 



"Warm-blooded animals, of course, 

 tend to reproduce in the late winter and 

 early spring so that their young mature 



enough to survive during the following 

 winter," Spence says. 



Sporting their golden robes, 

 prothonotary warblers migrate to North 

 Carolina to nest in cavities and 

 brighten the gray barks of trees like 

 Christmas ornaments. They flee the 

 tropics to seize the incredible flush of 

 insects that comes with the leafing 

 trees, says Mike Dunn, coordinator of 

 teacher education for the N.C. State 

 Museum of Natural Sciences in 

 Raleigh. 



"With the changing of the seasons, 

 you have these bursts of populations, 

 unlike in the tropics," he says. "These 

 migrants can now take advantage of the 

 abundant resources, because it takes so 

 much extra food to raise their young." 



For some fish species, such as 

 flounder, a spring meal means a ride of 

 a lifetime. The adults spawn offshore, 

 laying their eggs near the warm Gulf 

 Stream. Their larvae ride wind-driven 

 currents toward North Carolina's 

 inlets, where they arrive in time for the 

 estuaries' spring buffet. They make the 

 journey in 30 to 50 days, a tremendous 

 distance for creatures that are less than 

 an inch long, says Sea Grant researcher 

 John Miller, a zoologist at North 

 Carolina State University. 



"That, in fact, is equivalent — if I 

 scaled their bodies up to your size — to 

 you swimming around the planet in 30 

 days," he says, noting that besides 

 offering food, the shallow estuaries 

 present young fish with a safe hide- 

 away. "These estuarine waters are 

 oftentimes muddy and dark-stained, 

 and a lot of the predators are visually 

 looking for prey." 



The flounder babies spend their 

 summer feeding in the estuaries, and by 

 August, when they've reached about 6 to 

 8 inches and the food supply is dwin- 

 dling, they may return to the ocean. In 

 her lifetime, a female summer flounder 

 will spawn 10 times, producing 5 million 

 eggs, but on average only two of these 

 will live to reproduce. 



"More than 99 percent of these little 

 babies die before they are a year old," 

 Miller says. "They are playing a very 

 long-shot game. If they were more 

 successful, the population would be 

 increasing like crazy." 



Another well-known prolific 

 producer is the blue crab. 



When the waters begin to warm, 

 female crabs arise from their sediment 

 beds near coastal inlets and join males 

 furiously feeding in the estuaries, getting 



12 MARCH/APRIL 1997 



