During this time, each oyster passes through the hands of the farmer around 5 times. The farming cycle from laying down collectors to reaching the market size of the Mali Ston oyster takes two to three years. After the cement gets dry, ropes are installed to floating parks, where oysters continue their growth to the market size. One such rope contains from 40 to 80 oysters. The oysters are attached with cement to the plastic rope, 2 to 4 meters long. The most common technique of farming Mali Ston oysters to the market size is cementing. During this period of around one year, the oysters reach an adequate size for the next stage of farming. Crates and nets are continuously taken out so shellfish density is lowered. Juvenile oysters are put in baskets (crates) or nets which are tied to floating lines. Small oysters removed from the collectors continue their breeding process to the market size in different types of nets or crates. Together with the attached juvenile Mali Ston oysters, they are hung on floating installations where they can grow to their market size. Individual nets created by segmenting the net collectors are called pergolari. Net collectors can be segmented, after which oysters continue to grow on the same surface to which they were attached. The collectors are installed when there is a sufficient concentration of oyster larvae in the water column.īreeding of juvenile oysters to market size In the past, sheaves of wooden branches were used and today collectors made from plastic nets are mostly used. During the collection period, sea currents bring small oyster larvae onto these collectors, they attach and this marks the beginning of the breeding process.ĭifferent materials are used for collecting juvenile oysters. Farmers prepare collectors i.e., different base for collecting the spat and they place them on special locations along the seabed. The oyster spat is collected from the nature. It is also interesting that oysters are hermaphrodites and they change their sex several times during their life. It is interesting to note that one adult oyster can produce up to 2 million larvae in one cycle. Unlike the other areas, the specificity of Mali Ston Bay is that oysters spawn here twice a year, in spring and autumn. Once in the open sea, the larvae float with the sea currents for a while, after which they begin sinking to the seabed. The females keep the small larvae for a while, after which they release them into the sea to increase their chances of survival. It does not occur in the open sea but inside the female’s shell after the males release the gametes into the open sea and the females collect them through filtration. With an economic return of $7 for every dollar invested, oyster reef restoration in the Piankatank River is an important step towards bringing a vital natural-and economic-resource back to the Chesapeake Bay.īy restoring and repopulating large oyster reefs in key parts of the bay, we hope to reach a tipping point where oyster populations become sustainable, expanding their numbers and the benefits they and their reefs provide.Oysters from the genus Ostrea differ from the other oysters by fertilization. With the high productivity of the system, there is a high probability that restoration efforts will result in self-sustaining oyster populations. Considered a trap estuary, the circulatory pattern of water in the river helps to retain oyster larvae that will eventually attach to the hard substrate in the system (like the concrete and granite being placed by TNC) where the spat will grow. The Piankatank River was selected in part because of its unique flow and strong natural retention of oyster larvae. High pressure water hoses are used to deposit the smaller sized substrate floating cranes and barges are used to precisely place the granite in rows along the reef sites. Reefs have been constructed using clean, crushed concrete or granite. TNC has invested nearly $1 million into this decade-long restoration effort in the Piankatank, leveraging nearly five times that amount from our partners and surpassing the shared goals we set out to achieve for oyster restoration in this key tributary of the Chesapeake Bay.
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