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Fishing/Harvesting of Clams
Although some venerids fisheries occur in the subtidal zone of coastal areas, the
majority takes place in intertidal flats and shallow subtidal areas of estuaries, coastal
lagoons, sheltered bays, and mangroves. In these areas, the most common harvesting methods are hand picking, signing, digging, or raking. In hand picking, harvesters get down on their hands and knees or squat down and then sweep their hands
through the sediment to dislodge the clams. Signing and digging consists in walking
along the shore looking for siphon holes. When a hole is found, the harvester picks
the clam from the sediment with his hands or digs the clam out of the sediment
using simple tools such as spoons, knives, rakes, forks, shovels or grubber hoes.
Some harvesters use a clam gun to collect clams that are buried deeper into the sediment. This tool comprises a 10–15 cm diameter tube with a handle and a small air
vent at the closed upper end. When a hole is found, the tube is placed over it and
pushed down with an up-and-down, rocking, or twisting movement. When the clam
is enclosed, the air vent is blocked with a finger and the core of sand pulled up and
dropped on the beach to collect the clam. Raking is a technique that involves dragging a rake through the bottom until a scraping is felt. By that time, the harvester
pushes the rake into the sediment, pulls it towards him and upwards to collect the
clam. In shallow subtidal areas, treading is a widely used method that consists in
probing the bottom with the foot until a clam is felt. When a clam is found, the harvester simply bends down and picks it up. Hand dredging and bull raking are also
two common techniques used in shallow areas (ranging between 0.3 and 1.5 m
depth). Clam kicking is another harvesting method employed in the low intertidal.
In this method, the fisherman uses the propeller backwash to dislodge clams out of
the substrate, throwing them on the sediment surface. Then, clams are picked up by
hand, or using hand dredges or bull rakes. In sheltered areas and coastal zones ranging from 1 to 50 m depth, clams can be harvested by divers (Gaspar et al. 2013).
Some Important Species of Clams
Veneridae (Venus Shells)
The Veneridae or venerids, common name: venus clams, are a very large family of
minute to large, saltwater clams, marine bivalve molluscs. Over 500 living species
of venerid bivalves are known, most of which are edible, and many of which are
exploited as food sources. Many of the most important edible species are commonly
known simply as “clams”. Venerids make up a significant proportion of the world
fishery of edible bivalves. The family includes some species that are important commercially, such as the hard clam, Mercenaria mercenaria (Wikipedia 2019f).
Venus shells or Veneridae include the most important representatives of clam
species in the world. For example, Venerupis philippinarum or Manila clam, which
has been introduced to various parts of the world since the beginning of the twentieth century, is by far the most cultured clam species. The hard clam Mercenaria
3 Molluscan Shellfish
Fishing/Harvesting of Clams
Although some venerids fisheries occur in the subtidal zone of coastal areas, the
majority takes place in intertidal flats and shallow subtidal areas of estuaries, coastal
lagoons, sheltered bays, and mangroves. In these areas, the most common harvesting methods are hand picking, signing, digging, or raking. In hand picking, harvesters get down on their hands and knees or squat down and then sweep their hands
through the sediment to dislodge the clams. Signing and digging consists in walking
along the shore looking for siphon holes. When a hole is found, the harvester picks
the clam from the sediment with his hands or digs the clam out of the sediment
using simple tools such as spoons, knives, rakes, forks, shovels or grubber hoes.
Some harvesters use a clam gun to collect clams that are buried deeper into the sediment. This tool comprises a 10–15 cm diameter tube with a handle and a small air
vent at the closed upper end. When a hole is found, the tube is placed over it and
pushed down with an up-and-down, rocking, or twisting movement. When the clam
is enclosed, the air vent is blocked with a finger and the core of sand pulled up and
dropped on the beach to collect the clam. Raking is a technique that involves dragging a rake through the bottom until a scraping is felt. By that time, the harvester
pushes the rake into the sediment, pulls it towards him and upwards to collect the
clam. In shallow subtidal areas, treading is a widely used method that consists in
probing the bottom with the foot until a clam is felt. When a clam is found, the harvester simply bends down and picks it up. Hand dredging and bull raking are also
two common techniques used in shallow areas (ranging between 0.3 and 1.5 m
depth). Clam kicking is another harvesting method employed in the low intertidal.
In this method, the fisherman uses the propeller backwash to dislodge clams out of
the substrate, throwing them on the sediment surface. Then, clams are picked up by
hand, or using hand dredges or bull rakes. In sheltered areas and coastal zones ranging from 1 to 50 m depth, clams can be harvested by divers (Gaspar et al. 2013).
Some Important Species of Clams
Veneridae (Venus Shells)
The Veneridae or venerids, common name: venus clams, are a very large family of
minute to large, saltwater clams, marine bivalve molluscs. Over 500 living species
of venerid bivalves are known, most of which are edible, and many of which are
exploited as food sources. Many of the most important edible species are commonly
known simply as “clams”. Venerids make up a significant proportion of the world
fishery of edible bivalves. The family includes some species that are important commercially, such as the hard clam, Mercenaria mercenaria (Wikipedia 2019f).
Venus shells or Veneridae include the most important representatives of clam
species in the world. For example, Venerupis philippinarum or Manila clam, which
has been introduced to various parts of the world since the beginning of the twentieth century, is by far the most cultured clam species. The hard clam Mercenaria
3 Molluscan Shellfish