Holothuria whitmaei

Holothuria (Microthele) whitmaei, called the black teatfish, belongs to the sea cucumber family Holothuriidae. This species lives in the western Indian and Pacific Oceans, with recorded locations off Tanzania, New Caledonia, and the Philippines. Groups typically contain between five and twenty-five individuals.

H. whitmaei is now recognized as a distinct species, separate from H. nobilis, which once included it. Studies of two populations—one on the Great Barrier Reef and another on Ningaloo Reef—tracked seasonal patterns. The gonad index peaked from April to June. Microscopic and tissue analysis showed that large germinal tubules at the center of the gonad base move through four maturity stages: growing (II), mature (III), partly spawned (IV), and spent (V).

In a 2003 study, researchers could not explain why up to 23% of H. whitmaei specimens stayed hidden from sometime during the night until midday. However, another ecological study found that marked specimens became significantly more active in the first hours after marking, suggesting the marking process itself may skew results. A daytime study of thirty black teatfish on Ningaloo Reef revealed that the proportion of animals sheltered—and thus hidden when viewed from directly above—was much higher in the morning than in the afternoon. A separate study, using both marked and unmarked individuals, recorded peak activity between 2:30 and 5:30 PM.

Many sea cucumbers are boiled, dried, and processed into beche-de-mer, a valuable trade product in Pacific countries and communities, especially Papua New Guinea, the Solomon Islands, Australia, and Fiji. H. whitmaei ranks among the highest-value species; well-dried, A-grade product can sell for US$70–190 per kilogram, depending on size and quality. Since 2009, a moratorium due to overproduction has halted supply from Papua New Guinea. Fiji, by contrast, exports 243 tons of sea cucumber food annually.