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Mussels are organisms having separate sexes and fertilization takes place in the
water column. Eggs produced in ovaries and sperms produced in testicles are
sprayed from body to water. The genital opening where the sperm leaves the gonads
opens into the water outlet cavity above the gills and the sperm leave from the body
into this water. However, during spawning, since water outlet of the body is completely closed and a large part of the water inlet is closed, the eggs are collected in
the water inlet cavity and thrown away 30–50 cm away by a quick contraction of the
adductor muscle (Sirin 2012).
Mussels are creatures that are fed by filtering water. Both marine and freshwater
mussels are filter feeders; they feed on plankton and other microscopic sea creatures
which are free-floating in seawater. It can filter all kinds of organic and inorganic
particles with a size of 2–100 μm. A mussel with an average length of 7–8 cm can
drain 10–15 L of water per hour. However, in the filtration rate of mussels, mussel
size, particle size, particle density, particle type, water temperature, water flow play
an important role. When the nutrition of mussels is low, growth slows or stops. Meat
yield decreases and ripening of gonads is not complete (Sirin 2012).
Distribution of Mussels
Mussels settle on a wide variety of substrates, for example rock, stones, pebbles,
shell, cement, and wood, once the substrate is firm enough to provide a secure
anchorage. In the case of Perna, mangrove mudflats represent a major habitat for
tropical species. Early M. edulis spat either attach to filamentous algae, from which
they eventually migrate onto adult mussel beds, or else they settle directly onto
adult beds. On rocky shores mussel beds provide a habitat for a few but abundant
macro invertebrate species. Upper distribution limits for mussels are usually governed by physical factors, primarily temperature, while predators are mainly responsible for setting lower limits (Gosling 2015).
Marine mussels are abundant in the low and mid intertidal zone in temperate seas
globally. Other species of marine mussel live in tropical intertidal areas, but not in
the same huge numbers as in temperate zones. The South African white mussel
exceptionally does not bind itself to rocks but burrows into sandy beaches extending
two tubes above the sand surface for ingestion of food and water and exhausting
wastes. Freshwater mussels inhabit permanent lakes, rivers, canals, and streams
throughout the world except in the Polar Regions. They require a constant source of
cool, clean water. They prefer water with a substantial mineral content, using calcium carbonate to build their shells (Wikipedia 2019a).
Production and Trade of Mussels
World production of mussel reached 2.14 million tonnes in 2016, with a 35%
increase since 2007. Most of the production is farmed (94%), wild caught mussels
accounting for 6% of the volumes. The largest world producer of mussels is China
3 Molluscan Shellfish
Mussels are organisms having separate sexes and fertilization takes place in the
water column. Eggs produced in ovaries and sperms produced in testicles are
sprayed from body to water. The genital opening where the sperm leaves the gonads
opens into the water outlet cavity above the gills and the sperm leave from the body
into this water. However, during spawning, since water outlet of the body is completely closed and a large part of the water inlet is closed, the eggs are collected in
the water inlet cavity and thrown away 30–50 cm away by a quick contraction of the
adductor muscle (Sirin 2012).
Mussels are creatures that are fed by filtering water. Both marine and freshwater
mussels are filter feeders; they feed on plankton and other microscopic sea creatures
which are free-floating in seawater. It can filter all kinds of organic and inorganic
particles with a size of 2–100 μm. A mussel with an average length of 7–8 cm can
drain 10–15 L of water per hour. However, in the filtration rate of mussels, mussel
size, particle size, particle density, particle type, water temperature, water flow play
an important role. When the nutrition of mussels is low, growth slows or stops. Meat
yield decreases and ripening of gonads is not complete (Sirin 2012).
Distribution of Mussels
Mussels settle on a wide variety of substrates, for example rock, stones, pebbles,
shell, cement, and wood, once the substrate is firm enough to provide a secure
anchorage. In the case of Perna, mangrove mudflats represent a major habitat for
tropical species. Early M. edulis spat either attach to filamentous algae, from which
they eventually migrate onto adult mussel beds, or else they settle directly onto
adult beds. On rocky shores mussel beds provide a habitat for a few but abundant
macro invertebrate species. Upper distribution limits for mussels are usually governed by physical factors, primarily temperature, while predators are mainly responsible for setting lower limits (Gosling 2015).
Marine mussels are abundant in the low and mid intertidal zone in temperate seas
globally. Other species of marine mussel live in tropical intertidal areas, but not in
the same huge numbers as in temperate zones. The South African white mussel
exceptionally does not bind itself to rocks but burrows into sandy beaches extending
two tubes above the sand surface for ingestion of food and water and exhausting
wastes. Freshwater mussels inhabit permanent lakes, rivers, canals, and streams
throughout the world except in the Polar Regions. They require a constant source of
cool, clean water. They prefer water with a substantial mineral content, using calcium carbonate to build their shells (Wikipedia 2019a).
Production and Trade of Mussels
World production of mussel reached 2.14 million tonnes in 2016, with a 35%
increase since 2007. Most of the production is farmed (94%), wild caught mussels
accounting for 6% of the volumes. The largest world producer of mussels is China
3 Molluscan Shellfish