Black Sea Bass Populations

While working on the story Saving Black Sea Bass, I realized how important it is to protect the habitat of black sea bass so it can mature, spawn and grow the population. It just makes sense. But it’s even more important to understand in the case of the black sea bass because these fish are protogynous hermaphrodites.

That means they generally first mature as females and some become males later in the life cycle. The sex change usually occurs over the winter when the fish is about 240mm to 330mm (9.4in-13in) long. That’s about half its adult size, which is usually about 500mm (20in) long. It’s still not clear what triggers the change.

What is known is that the sea bass spawns when it is mature at about 190mm (7.5in). That usually happens in May and June. The floating eggs take about two days to develop. The larvae drift and swim into the estuaries where they find food and shelter. They grow up and return to the ocean in the fall. 

Scientists say there are three large populations of black sea bass; the mid-Atlantic stock, which reaches from Cape Cod in Massachusetts to Cape Hatteras, the South Atlantic stock, reaching from Cape Hatteras to the southern tip of Florida, and the Gulf of Mexico stock, spanning from South Florida to Texas.

There may be different populations but they all live essentially the same way. They can be found in bays, estuaries and offshore in the ocean. They often gather around bottom formations such as rocks, man-made reefs, wrecks, jetties, piers, and bridge pilings.

Because they are good eating and relatively easy to catch, black sea bass populations have been in danger of being overfished. Quotas are enacted by state and regional fisheries councils, based on the analysis of yearly catches and fisheries surveys.

— Frank Graff

Frank Graff is a producer/reporter with UNC-TV, focusing on North Carolina Science Now, a weekly science series that airs Wednesdays, beginning in August 2013, as part of North Carolina Now on UNC-TV. In addition to producing these special segments, Frank will provide additional information related to his stories through this North Carolina Science Now Reporter's Blog!

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