Pearls in the Web of Life - Part 2

In a sense, pearl oysters might be a “small ecosystem” of their own, a self-contained biome where a tug of war ensues and leads to eventual stability. But why does this happen? And does it hurt the mollusk? One of my Marine Biology teachers -Dr Fernando Manrique, a friend of Jacques Cousteau- once told us that the Ocean was teeming with Life, and that the hardest thing for many lifeforms to find was an “available apartment”, a place to settle and that would help them avoid being tossed around by waves and water currents. Rocks are the best “condos” in this aquatic world, but oyster shells are a good second place. And because of this, a pearl oyster’s life become that of a patient renter, never asking much and sometimes suffering from being too lenient with its established guests.

Pearl oysters can become so attractive to other lifeforms that they may become completely covered by these “epibionts” (from the Greek “Epi”, which means “On top” and “Bio” for “Life”) and the mollusks may weaken due to lack of oxygen and food, and this is the main reason why pearl farmers must clean their oysters several times a year, sometimes even on a monthly basis. The traditional cleaning method involves manual labor; thus, oysters are individually scrapped free of these creatures. This is a time consuming and costly operation, and it may stress the oysters just a bit (but much better than leaving them to slowly suffocate).

In Nature, there are other creatures that clean the oysters and there are more natural strategies to clean them. For instance, Australian pearl farmers may lay their flat-panel baskets, with their valuable pearl-bearing oysters, right on top of the sandy bottom, where these epibionts will suffocate and die; in another pearl farm in Ahe, Tahiti, the oysters will be hanging from ropes and are placed in a reef area, teeming with colorful fishes that will eat-away all the plants and invertebrates off the shells. Both are simple, all-natural and effective methods to clean your oysters and promote their health and growth, to help them produce beautiful pearls.

Callo Ostra y Pepino

Black Lipped oysters (Pinctada mazatlanica) in their pearl bed, next to a pen shell (left, Pinna rugosa) and a sea-cucumber (top right, Isostichopus fuscus). Sea cucumbers, and other invertebrates, also eat the “epibionts” (plants and animals) that grow on top of these mollusks.