Capiz Shells (Placuna placenta)

Description and Characteristics

Capiz is an aquatic mollusk that has a compressed body enclosed within a hinged shell. It has different names such as capiz shell, hatchet-footed shells, and windowpane shell.  The name “capiz shell” was generated because these shells were harvested near and found in abundance in a small town called Capiz in the Philippines. It has two main parts: the shell and the meat enclosed within the shell. The shell reveals a translucent silvery color when cleaned and measures up 70 to 100 millimeters in length.  Capiz shells are usually more flattened compared to other mollusk species and with a V-shaped ligament ridge showing near its hinge. The shells serve as its protection from the outside environment. The “meat” of Capiz which is sheltered inside the shells is white, soft, and is composed of different organs including its kidney, digestive gland, ventricle, rectum, and foot. Sexes are differentiated by the color of the gonad. When the gonad is well developed, the females have orange yellow appearance while males have cream white color. Capiz shells also produce pearls that normally are ivory or white in color and relatively small in size that’s why it’s pearls are less of economic value compared to other pearl-producing mollusks. Capiz is commonly branded by its glass-looking shells which made it famous around the world for the different products that can be produced out of these shells.

Photo and copyright: The Malacological Society of London| http://malacsoc.org.uk/malacological_bulletin/Mini-Reviews/3Aquaculture/Aquaculture.htm

Location and Sources

Capiz shells are commonly found on muddy or sandy bedrocks from shallow water to depths of up to 100 meters. They naturally exist in bays, coves and estuaries. Capiz shells can also be grown in areas with water temperature 24.5-30 degrees Celsius, salinity 18-38 ppt, pH 6.4-7.7 and dissolved oxygen 2.5-5 ppm. Ideally in transplanted areas, density should be limited to at most 200 shells per square meter that is to allow normal growth and prevent overcrowding. This species is abundant in Capiz, Philippines but are also distributed in some of its neighboring provinces. One large supplier/manufacturer of products made from capiz shells is Jumbo Pacific Inc. which is located in Cebu. Furthermore, capiz shells are also present in the Mindanao region. Capiz can actually be grown anywhere as long as it meets its needed environment conditions.

Application and Product Output

Capiz shells were first used in the Philippines during the Spanish occupation in making slide windows for churches. From then on, people discovered the infinite use of its shells. There are several ideas about using the Capiz shells as a resource in the Philippines including window panes, jewelry, ornaments, kitchen utensils, and for fashion.

Capiz shells are initially muddy and jagged before they are processed. The production starts by cleaning the shells after harvesting, they are then soaked in tubs of water and mild acid to further clean and soften them. After soaking, they are laid out under the sun to dry. Dried shells can now be cut, varnished, and formed into different shapes and sizes and can also be colored by applying bleaches and dyes. The sky’s the limit when it comes to creating different products out of the capiz shells. It can be made into different home products and decorations such as curtains, chandeliers, lamp shades, lanterns, wall-mounted decors, candle holders, tiles, wall panels, plates, bowls, trays, picture frames, etc.  It can also be made into fashion jewelries, accessories, and gift items. Capiz shell is known to be a very versatile material that you can do a lot of possible things with. There are actually many Filipino artisans and craftsmen whose mastery is on creating different designs and products out of capiz shells some of which are made available online. 

Capiz shells made into lampshade, curtain, chandelier, hanging décor, liquid soap dispenser, jewelry boxes, wall-mounted décor, and candle holder. Photo and copyright: emceer via Pinterest | https://www.pinterest.ph/emceer/capiz-shell-products/

On the other hand, the meat of capiz shells can be used as food if it’s still fresh. The meat can be eaten raw complemented with a dipping sauce such as vinegar, or it can be sautéed. Capiz is usually dried under the sun to allow it to open naturally. Thus, reducing the damage to the shell as the meat is being detached from the inside. The removed meat is often used as a component for poultry and shrimp feeds.

Production and Sustainable Consumption

Through time, capiz shells have helped people both as food and as a way of living. In the Philippines, there are already small and big scale production of capiz shells for which the locals have depended on their income by working in farms and factories of capiz shells. Its capacity to be transformed into diverse products resulted in a very high demand and the different sources/producers are increasing their supply in order to conform.  Capiz shells used to be easily found in the Philippines as they naturally reproduce in their desired environment, and harvesting is not yet severe and in-demand compared to today’s circumstances. Currently, capiz shells in the Philippines are starting to become limited and the decline started as early as the 1970s. Overexploitation and the destructive methods of fishing and gathering such as trawling, using mechanical rakes and dredges, dynamite fishing, and compressor diving are the main reasons as to why this species is declining in numbers. Water pollution specifically chemicals disposed of in the sea and flushed water laced with antibiotics from prawn hatcheries contaminates used-to-be-homes of capiz shells resulting in its degeneration. The government already initiated actions to sustain the industry for capiz shells by establishing fisheries regulations to control harvesting and aquaculture. It includes issuing licenses and permits before harvesting, setting minimum and maximum landing sizes (shells with sizes less than 80 millimeter and more than 100 millimeter are prohibited to be harvested), establishing restricted areas, and devising fines and imprisonment for those who are doing dangerous things that can put the capiz in danger.

Supported by the Connections Through Culture Programme of the British Council, our Materials Library Expansion Project is the first collaboration between UNESCO Creative Cities of Design #Cebu and #Dundee. #MATIC #CreativeDundee #BritishCouncilPh #BritishCouncilCTC

Works Cited

“All About Capiz”. Cultural Elements: Elements, https://blog.culturalelements.com/all-about-capiz/. Accessed 25 January 2021.

“Famous Capiz Shell of The Philippines”. Jumbo Pacific Inc.: Capiz Shells Blog, https://capizshells.com/capiz-shell/. Accessed 25 January 2021.

“The Malacologist”. The Malacological Society of London, http://malacsoc.org.uk/malacological_bulletin/Mini-Reviews/3Aquaculture/Aquaculture.htm. Accessed 25 January 2021.

Narasimham, K.A. “Biology of windowpane oyster placenta placenta (linnaeus) in Kakinada Bay”. Kakinada Research Centre of C. M. F. R. Institute, https://core.ac.uk/download/pdf/33010879.pdf. Accessed 25 January 2021.

Park, Monica. “Capiz Shells and Their Uses”. PBWORKS, http://ecop.pbworks.com/w/page/18520528/Capiz%20shells%20and%20their%20uses%200809. Accessed 25 January 2021.

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