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You are here:   animal list > Pinctada margaritifera




Pinctada margaritifera

Black lipped pearl oyster

Megan Van Dyk (2011)




Fact Sheet


Brief Summary

Comprehensive Description


Physical Description

Identification Resources


Disease and Predation


Environmental Factors

Reproduction and Development

Sexual Morphology and Physiology

Spawning Seasonality

Larval Development

Evolution & Systematics

Fossil History


Morphology and Physiology

External Form and Function

Internal Anatomy and Function



Feeding Rate

Respiration and Gas Exchange

Molecular Biology & Genetics

Molecular Biology

Nucleotide Sequence

Pearl Aquaculture

Economics and Pearl Farming

Pearl Production and Formation


References & More Information

Content Partners


Biomedical Terms

Names & Taxonomy

Related Names


Common Names

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Content Summary

Respiration and Gas Exchange

Pearl oysters, like other bivalves, obtain oxygen from the surrounding water as it passes through the mantle cavity. The gill filaments and mantle have large surfaces lined with fine permeable epithelia where the circulating hemolymph is in close proximity with the water flowing through the mantle cavity. Total oxygen consumption increases with pearl oyster size which relates to the mass of metabolizing tissue.

The energy-yielding oxidative processes of metabolism are usually aerobic in pearl oysters, although anaerobic metabolism may occur in some circumstances. Oxygen for aerobic metabolism is extracted from the water flowing through the mantle cavity and CO2 is discharged. The gill filaments contain hollow tubes through which hemolymph flows and deoxygenated hemolymph thereby comes into close contact with the seawater flowing over the filaments. There is reciprocal exchange of O2 and CO2 as they diffuse passively across the fine filament membranes according to the gradients between seawater and hemolymph. There is also some gas exchange between seawater and hemolymph across the large permeable surfaces of the mantle.

Oxygen diffuses passively from the water found in the mantle cavity with its higher partial pressure of oxygen (PO2) to the lower PO2 levels in the hemolymph that result from oxygen consumption due to aerobic metabolism. Rate of oxygen uptake depends on the PO2 gradient between the surrounding water and hemolymph.  Keeping  the gills and mantle well irrigated with high PO2 water is also important. There is an estimated relationship between the oxygen dissolved per unit volume of water (DO) and PO2. Temperature, salinity and pH are factors that influence the DO: PO2 relationship. However, at the moderately stable salinities and pH of seawater, and within reasonable temperatures there is a good association.