Aquaculture and Fisheries Commons^™

The Shellfish Corner: Filter Feeding Bivalves As Processors Of Coastal Waters, Michael Rice

Michael A Rice

Bivalves have a profound role in controlling the boom and bust cycles of seasonal phytoplankton blooms, and the increased rates of sediment deposition to the bottom by bivalves are an important "coupler" between the water column and the bottom that stimulates the rate of decomposition and other processes in the sediments.

The Shellfish Corner -- Shellfish And The Problem Of Ocean Acidification, Michael A. Rice

Michael A Rice

The acidification of the world's oceans due to increasing atmospheric carbon dioxide concentrations is creating a problem in the dissolution of larval shells of mollusks and creating problems for shellfish hatcheries. Hatcheries can mitigate the problem by treating incoming seawater with alkaline sodium carbonate, but there is evidence that acidic sediments in some locations are a source of considerable post-settlement loss of newly set juveniles.

A Review Of Shellfish Restoration As A Tool For Coastal Water Quality Management., Michael A. Rice

Michael A Rice

In many areas, coastal residents and others oppose establishment of bivalve molluscan aquaculture projects on the basis of perceived negative environmental impacts. Often overlooked are positive environmental impacts of shellfish aquaculture that can potentially mitigate the impacts of other anthropogenic activities. Filter feeding by populations of bivalve mollusks is reviewed with respect to their ability to act as an estuarine filter, increase clarity of coastal waters and facilitate the removal of nitrogen and other nutrients from eutrophic coastal waters. Most species of cultured bivalve mollusks clear particles from waters at rates of 1 to 4 L/h, and populations of shellfish …

Uptake Of Dissolved Free Amino Acids By Northern Quahogs, Mercenaria Mercenaria, And Its Relative Importance To Organic Nitrogen Deposition In Narragansett Bay, Rhode Island, Michael A. Rice

Michael A Rice

Studies were undertaken to determine the relationship between size of northern quahogs Mercenaria mercenaria and the rate at which they transport aspartic acid. Quahogs ranging from 25 to 103 mm valve length were collected in Narragansett Bay and placed in seawater aquaria (27 ppt, 20 deg C) and allowed to pump actively. Uptake experiments were carried out using 1 umol/L C(14) radiolabeled aspartic acid. Aspartate transport rates in umol/h can be related to valve length by the allometric equation with a = 24.32 and b = 0.905 when valve length is in mm. In May 1990, near bottom samples of …

A Review Of The Factors Influencing The Growth Of The Northern Quahog, Mercenaria Mercenaria (Linnaeus, 1758), Michael A. Rice, Jan A. Pechenik

Michael A Rice

Factors affecting the growth of larval, juvenile, and adult northern quahogs, Mercenaria mercenaria, are reviewed. Larval growth is affected by temperature, salinity, current speed, dissolved oxygen concentration, and the amount of suspended sediments in the water, along with such nutritional factors as food quantity and quality. Growth of post-set juvenile and adult quahogs is similarly affected by the same physical and nutritional factors. Recent work suggests that there is a strong genetic contribution to quahog growth rate and that selective breeding programs may be useful for producing rapid growth strains. A growing body of evidence suggests that larval growth rates …

Effects Of Intensive Fishing Effort On The Population Structure Of Quahogs, Mercenaria Mercenaria (Linnaeus, 1758), In Narragansett Bay, Michael Rice, Charles Hickox, Itrat Zehra

Michael A Rice