recorded depth is 55 m. Reproduction Macrostrombus costatus has external sex organs. Male milk conchs have a verge, while female milk conchs have an egg groove. Milk conchs are oviparous. These marine gastropods begin to spawn in early November throughout the winter and spring seasons. Spawning comes to an end in May. They have been found to aggregate in groups to spawn in locations of open sand and deeper waters. Life cycle Macrostrombus costatus begins its life developing inside eggs as planktonic larvae. The larvae, known as veligers, feed on different cultures of phytoplankton for nutrition to support growth. Then, as a pelagic veliger, the milk conch reaches metamorphosis to a benthic snail in approximately 26–30 days after hatching. The development of the proboscis (contains part of the oral cavity and radula), the loss of velar lobes, and the eyes migrating outwards occur provide morphological evidence of metamorphosis. Juvenile milk conchs have a distinguished conical shaped shell with tight whorls and green-colored proboscis. At this stage, they begin grazing on algae via their proboscis. Crustaceans, such as crabs and lobsters are their main predators when they are juvenile. Feeding Macrostrombus costatus is a herbivorous marine gastropod. As veligers, they consume phytoplankton. As adult snails, they feed mostly on algae. Threats Macrostrombus costatus is fished for its meat and ornamental shell along the tropical Atlantic regions. The species has commercial importance, especially in the Caribbean, but the total catch volume has not been estimated. It is believed that Macrostrombus costatus is overfished. Therefore, there may be a major decline in the species populations. In Panama, there are no current regulations on the harvesting of milk conch. The conservation status of the species is unknown, due to lack of research. References Further reading Rosenberg, G., F. Moretzsohn, and E. F. García. 2009. Gastropoda (Mollusca) of the Gulf of Mexico, Pp. 579–699 in Felder, D.L. and D.K. Camp (eds.), Gulf of Mexico–Origins, Waters, and Biota. Biodiversity. Texas A&M Press, College Station, Texas External links Strombidae Gastropods described in 1791 Taxa named by Johann Friedrich Gmelin