What is Aquaculture?

Queen conch egg masses can be collected from wild populations or from an egg farm. An egg farm is an enclosure in the wild where adult conch are stocked to ensure a steady supply of egg masses.

Conch have separate sexes and are sexually mature at 4 years old. The male is on the left and female on the right.

Conch have internal fertilization and the male (right) and female (left) conch need to be at a density of at least 100 conch per hectare (2.2 acres) in order to find each other for mating. 

Photo credit: Michiel van Nierop

Each female conch lays about 10 egg masses during the summer breeding season, which is typically April to September. Each egg mass contains about 500,000 eggs.

Small portions of the egg mass are collected from the female and brought back to the hatchery inside a bucket of salt water. 

Queen conch eggs take 3-5 days to hatch and will hatch at 9:00 PM.

Queen conch egg mass is one continuous strand that is covered in sand grains. The egg mass is about five inches long and has 500,000 eggs. 

Using a microscope, you can see the tiny embryos inside the egg mass strand. For reference, those white pebbles are grains of sand! Once ready to hatch, the embryo's foot will have orange pigments, the velar lobes are visible and the embryo will steadily rotate in its egg capsule. 

 Newly hatched veligers have a distinct, elongated beak, two velar lobes, and a light-colored gut. The black eye spots and orange pigments on the foot are visible. Shell length is 350 – 370 µm and the shell has 1.5 whorls.

 By day 4 the velar lobes have indented to form four lobes. The foot has expanded and the orange pigments multiply near the bottom portion of the foot. Phytoplankton makes the veliger digestive glands brown. The cilia on the lobes are used to aid the larvae in feeding, respiration and movement. Shell length is 440 – 470 µm and the shell has 2 whorls. 

This 18 days old veliger has 6 lobes and a dark brown gut from feeding on phytoplankton. As the veliger approaches metamorphosis competency, the foot greatly expands, the adult operculum becomes visible and the orange foot pigment is starting to show dark spots. Some veligers exhibit swim-crawl behavior. The shell length is 830 - 1130 µm and has 3 whorls.

 Around day 21 the veligers undergo metamorphosis. The conch veliger needs a metamorphic cue to settle. The metamorphosed conch absorbs its velar lobes and crawls with its foot. The eyes have migrated up the tentacles and the proboscis is used for grazing. The shell length two days after settlement is 1280 – 1760 µm.

Conch need to be 7-9 cm (3-3.5 inches) in shell length to be stocked for ranching or restoration. The largest conch in this photo is about 1 to 1.5 years old.

Ranch enclosures are used to grow the conch for food. The enclosures are secured to the  sandy and seagrass substrate on the bottom and extend above the surface to limit predation.

The conch are stocked at 1-2 conch per square meter (10 square feet) in the pasture. The enclosure should be at least 25 meters (80 feet) in diameter. This density mimics that of the wild. If enclosures are stocked higher, then pasture rotation is necessary. 

These conch range in age from 1 to 4 years old.

 Size plays an important role in determining stocking and harvesting phases. 

Photo Credit: H. Forrest Thomas

Juvenile conch are collected from the nursery tanks  and relocated to the ranch enclosures via boat.

Conch are stocked into the wild for restoration by hand to ensure they are sheltered in the seagrass meadow.