About Cromileptes altivelis (Valenciennes, 1828)
The humpback grouper, scientifically named Cromileptes altivelis (Valenciennes, 1828), is a medium-sized fish that grows up to 70 cm (28 in). Its unique body shape means it is rarely confused with other fish. Its body is laterally compressed and relatively tall, with a distinct head profile compared to other groupers. The head is depressed at the front and elevated at the back, with a sharp upward curve at the nape. This stocky shape creates the characteristic humpbacked appearance. Genetic evidence shows increased activity in this species’ frontal osteoblasts, which may be the genetic basis for the sunken, humpback-shaped frontal bone of C. altivelis. Juvenile humpback groupers are white with round black spots, while adults have bodies in varying shades of grey and beige, with variable-sized darker blotches across the body. The entire adult body is covered in small black spots. Juveniles have fewer black spots than adults, but their individual spots can be as large as their eyes. This species’ coloration has been observed to change when pH drops. The humpback grouper has rounded pectoral and caudal fins that help with swimming stability. Its pectoral fins have between 17 and 18 rays, with the middle rays being the longest. It also has a long dorsal fin that starts at the opercle and runs all the way to the caudal fin. The dorsal fin has around 10 spines and 17–19 rays, which improves stability against turning. The anal fin is roughly half the length of the dorsal fin, with around 3 spines and 9–10 rays. It has brush-like villiform teeth suited for eating smaller fish, and its body is covered in smooth scales. This species is widely distributed across tropical waters of the central Indo-West Pacific region. Humpback groupers live in clear waters of lagoons and seaward reefs, and prefer dead or silty areas. They are found at depths between 2 and 40 m (6.6 to 131.2 ft), but most occur at depths less than 10 m (32.8 ft). They prefer a water temperature of 24.5 C, similar to other cool temperate freshwater fish. This grouper has a non-native distribution in Florida, where it was first recorded in 1984, with the last recorded observation in 2012. It has been spotted in Florida’s Tampa Bay, Pompano Beach, and West Beach. In 2012, a single 78 cm, 15 lbs (6.8 kg) individual was speared near Key Largo, leading to concerns that it could become invasive similar to lionfish. As of 2013, no established breeding populations of humpback grouper exist in the western Atlantic, despite these concerns. Researchers have identified Jupiter and Vero Beach in Florida as likely locations for the species to establish populations. In Hawaii, the humpback grouper was first observed in 1991, but it has since been extirpated, with the last local observation in 2005. There is also one recorded observation of the species in Kenya. This species is a protogynous hermaphrodite: all individuals hatch as female, and gain the ability to change sex to male as they age. Female humpback groupers can begin transitioning to male as early as 3 years old, and most individuals are male by age 9. Usually, only the most dominant mature females change sex when a dominant male is absent. The species is primarily solitary, but it has also been observed swimming in pairs, or occasionally in groups of 3 to 6 individuals. The purpose of these groups is unknown. Compared to other closely related groupers, the humpback grouper has a slow growth rate, and females reach sexual maturity around 1.5 years old. Testing of cryopreservation on humpback grouper embryos found a 7.55% survival rate, with a maximum viability period of 5 days. The peak spawning period for humpback groupers falls between October and January, and a single spawning event lasts 4 to 8 days.
