tulipa spatfall than upper-horizontal surfaces in the main experiment ( P < 0.01). The under-horizontal surfaces of collectors, had significantly more C. Spat collection with 2 mm nylon mesh was not successful. Coconut shell consistently had the least C. This settlement was not significantly different from settlement on PVC slats ( P > 0.05) with the highest settlement in Densu Delta (2880 ± 294 spat m −2). Ceramic tile had the highest mean monthly spat settlement in the Narkwa Lagoon (3451 ± 206 spat m −2), Benya Lagoon (1769 ± 145 spat m −2) and Whin Estuary (373.1 ± 52.4 spat m −2). tulipa spat from the Densu Delta, Narkwa Lagoon, Benya Lagoon and Whin Estuary, along the coast of Ghana from November 2017 to October 2018. We assessed the effectiveness of five substrates (coconut shell, oyster shell, nylon mesh, PVC, and ceramic tile) for harvesting C. The current background information to support this venture is, however, inadequate. If you're interested in learning more about the pros and cons of different gear types, there are a lot of resources online, but this document from Sea Grant and NOAA does a pretty good summary and is a great starting point.The West African mangrove oyster, Crassostrea tulipa (Lamarck, 1819), has the potential to improve global shellfish food production and is being considered for commercial farming in many countries in West Africa. What kind of cool grow-out methods have you seen used around the world? If you're an oyster grower, what kind of grow-out method do you prefer to use? And like we mentioned in our other post, that's what's exciting about the oyster industry: there is always something new on the horizon. Different farms are discovering what works for them and their geographies. The methods we outlined above aren't even comprehensive of all the methods that exist in the world. There is obviously no one way to grow oysters, and many growers use a combination of grow-out methods. Like surface culture oysters, suspended culture oysters are constantly getting wave action. As the tide goes in and out, the bags are constantly flipped and moving up and down. There are also other suspension systems such as an adjustable long-line where cages, trays or bags hang from a long line that can be hauled up to be tended. Now imagine the tide coming in and the buoy rising above the suspension line with the grow-out bags hanging vertically. The photo above shows the Shigoku farm when it's dry. In other words, the oysters are hanging under water and they rise and fall with the tides. In a suspended culture, the oysters are typically suspended from a buoy that floats on the surface of the water. Here are some off-bottom methods that are commonly used. We won't get into oyster growing techniques. that can be a whole discussion in itself. Sometimes there is a tendency for oysters to be brittle because they are so pampered, but there are many techniques growers use to strengthen the shell (e.g. The disadvantages, though, include more money spent on gear and more work keeping the gear from fouling. As you will see, oysters are typically enclosed and protected in off-bottom methods, so a grower has the potential to lose less oysters to weather. The main advantage of off-bottom methods is the opposite of bottom culturing's disadvantages. For example, if oysters are grown on a beach, off-bottom culturing may be the only viable grow-out method because otherwise, oysters would risk getting buried as the sand shifts with weather. Growers typically decide their equipment based on the geography of their farm-site and personal preference. These methods vary mainly because of the oyster gear a grower decides to use. A List of Off-Bottom MethodsĪlthough "off-bottom" sounds pretty straightforward, there's actually a huge variety of off-bottom methods.
Every oyster lost is one less oyster a grower can sell for income. Oysters may die from suffocating under the bottom, get attacked by predators, or become frozen in ice that takes them out into the ocean. However, the greatest disadvantage, which might outweigh the advantages, is that growers can lose many oysters to mother nature.
Some think the shells are stronger because they absorb minerals from the mud, or because they get more wave action during tidal changes and rough weather. There are a number of speculations why that is. The main benefit of bottom culturing is the ability to produce robust and hearty shells. It goes without saying that each method has its advantages and disadvantages.
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