The grouper family has a lot of fish trimmed in yellow, and all of them are good to eat.
The yellowfin and yellowedge groupers both have fin edges trimmed with wide canary-yellow bands. This is especially noticeable in their pectoral (side) fins.
Scamp and yellowmouth groupers have yellow-splashed mouths. The color is much more prominent in the aptly named yellowmouth than the scamp. Additionally, yellowmouth groupers have yellow pigment on the skin near their eyes and small yellow band on the trailing edges of their tail fins.
If all else fails, they can be separated by — no kidding — comparing the sizes of the nostrils. In yellowfins, the front and rear nostrils are the same size. In scamp, the rear nostrils are larger.
The two species are very closely related and share many common features, such as lyre-shaped, broomed tail fins.
Scamp are found from North Carolina down the Atlantic and Gulf coasts to Venezuela. Yellowfin grouper are a more southern species, and reach their peak populations in the islands of the Caribbean, although a surprising number of yellowfins are caught off of Louisiana and misidentified as scamp.
They taste the same on the table — absolutely delicious.
They are medium-sized groupers. The world record for scamp is 29 pounds, 10 ounces. For yellowfins the record stands at 22 pounds, 8 ounces.
Scamp (Mycteroperca phenax) and yellowfin grouper (Mycteroperca interstitialis) share the same genus name, which translates from Greek roots as “nose perch.”
The species name for yellowfin grouper, "interstitialis,” is derived from Latin and refers to having small spaces or intervals between things or parts.
Yellowfins were first named by scientists in 1860. Scamp weren’t named until 1884. Because of its close resemblance to the yellowfin, the naming scientists chose the species name phenax from Greek, meaning “imposter,” due to its resemblance to its close relative and previous misidentifications.
Their biology is very similar, so from this point on the narrative will be about scamp, the most common species in Louisiana.
While some grouper species are common over relatively smooth but hard bottoms, scamp prefer rugged bottoms with a lot of hard features. They show a preference to heavy coral growth where it is present.
Offshore oil and gas platforms provide lots of relief, or “structure,” as bass fishermen would call it. And scamp are strongly attracted to them. This tendency would seem to make them easy to locate and overfish, but scamp have been found to be less aggressive than other groupers such as gag, with which they share their habitat.
Groupers as a family are considered susceptible to overfishing because of a quirk in their life cycles. Most, if not all of them, are “protogynous hermaphrodites.” The same fish will be male and female — not at one time of course, but in the course of their lives.
“Protogynous” means they are females first, and then later in life they change to males.
The trigger for the change in scamp doesn’t seem to be size related as much as it is dependent upon the social structure of the fish community. When males are not present in adequate numbers, the largest of the females change sexes. If they are fished out, then even smaller females change to males.
Fishing selectively removes the largest fish from grouper populations. Bigger groupers dominate smaller groupers and dominate access to food supplies. Of course, this includes baited hooks.
This causes two potential problems. First and most obvious is the fact that not enough males might be present to fertilize females’ eggs. Secondly, large females produce a lot more eggs per fish than do small females; when removal of large males takes place, the largest females change sexes and are no longer egg-producers.
This is aggravated by the fact that scamp (and yellowouths) form spawning aggregations. Fish will travel long distances to form these spawning groups. Grouper spawning aggregations tend to form in the same place year after year, so fishermen who know these locations can hammer them hard.
Fortunately, scamp mature quickly. By a little over a year old and at only 12 to 13 inches long females (remember, they all start life as females) are sexually mature.
Spawning in the Gulf of Mexico occurs from February to July, with a peak in March to May.
Spawning takes place in late afternoon or in the evening. Higher proportions of scamp spawn at new and full moons.
Their fertilized eggs are free-floating, at the mercy of currents and water movement. Scamp can live to 30 years old if they make it past the vulnerable larval stage.
Scamp can be found in waters as shallow as 40 feet and as deep as 625 feet, although they are most common at depths of 130 to 265 feet. Few fish over 4 pounds are found in waters shallower than 60 feet.
At their favored depths, they prowl just off the bottom looking for their favorite prey — fish, although they will eat crabs or shrimp as well.
The five most-frequently identified food items in their diet are round scad, Atlantic bumpers, unidentified serranids (other fish in the grouper family), vermilion snappers and tomtate grunts.