Eve Galimany

SEVERAL CASES OF DISSEMINATED NEOPLASIA IN MUSSELS MYTILUS EDULIS (L.) IN WESTERN LONG ISLAND SOUND

Abstract Eight cases of disseminated neoplasia were found among 540 specimens of Mytilus edulis collected from an intertidal beach in Connecticut in western Long Island Sound. This was unusual, because disseminated neoplasia is very rare in M. edulis but causes epizootic mortalities in another mussel species, M. trossulus. According to histology, mussels showed a continuum of disease progression, from early stages with a few anaplastic cells around the stomach epithelium to more advanced cases with multiple foci of neoplastic cells in the tissues, finally to terminal cases with profuse infiltration of neoplastic cells in all tissues. Flowcytometric hemocyte analyses were performed to compare immune functions between neoplastic and healthy mussels. Circulating hemocytes from the neoplastic mussels showed significantly less phagocytosis and significantly more apoptosis than hemocytes from the healthy mussels. Hemocyte cell density measured by flow cytometry increased in the hemolymph with progression of the disease on histological sections. In situ hybridization was performed to detect apoptosis also on paraffin sections. There were more apoptotic neoplastic cells in the early stages of the disease than in the later stages. These observations suggest the need for further studies on apoptosis-regulating genes to explain differences in susceptibility to neoplasia of different Mytilus species, and the role of apoptosis in the progression of disseminated neoplasia.

First evidence of fiberglass ingestion by a marine invertebrate (Mytilus galloprovincialis L.) in a N.W. Mediterranean estuary.

Alfacs Bay is a N.W. Mediterranean estuary important for mussel (Mytilus galloprovincialis) aquaculture. During studies at the site, fiberglass particles were detected. The presence of fiberglass occurred naturally in the water throughout the study period (November 2006 to July 2007). An investigation was undertaken into its role in the feeding behavior of the local mussels. Fiberglass was present in all types of mussel samples. Rejection, which we would have expected for the whole study period, was only evident during the second season studied. To our knowledge, this is the first report of the ingestion of fiberglass by a marine organism. Our novel finding indicates the need to investigate fiberglass ingestion by marine organisms at different levels of the food web and the possible implications for human health and the health of the organisms themselves. In addition, we propose the use of mussels as sentinel organisms to monitor fiberglass contamination in marine ecosystems.

Design and Use of an Apparatus for Quantifying Bivalve Suspension Feeding at Sea

As shellfish aquaculture moves from coastal embayments and estuaries to offshore locations, the need to quantify ecosystem interactions of farmed bivalves (i.e., mussels, oysters, and clams) presents new challenges. Quantitative data on the feeding behavior of suspension-feeding mollusks is necessary to determine important ecosystem interactions of offshore shellfish farms, including their carrying capacity, the competition with the zooplankton community, the availability of trophic resources at different depths, and the deposition to the benthos. The biodeposition method is used to quantify feeding variables in suspension-feeding bivalves in a natural setting and represents a more realistic proxy than laboratory experiments. This method, however, relies upon a stable platform to satisfy the requirements that water flow rates supplied to the shellfish remain constant and the bivalves are undisturbed. A flow-through device and process for using the biodeposition method to quantify the feeding of bivalve mollusks were modified from a land-based format for shipboard use by building a two-dimensional gimbal table around the device. Planimeter data reveal a minimal pitch and yaw of the chambers containing the test shellfish despite boat motion, the flow rates within the chambers remain constant, and operators are able to collect the biodeposits (feces and pseudofeces) with sufficient consistency to obtain accurate measurements of the bivalve clearance, filtration, selection, ingestion, rejection, and absorption at offshore shellfish aquaculture sites.

Cultivation of the Ribbed Mussel (Geukensia demissa) for Nutrient Bioextraction in an Urban Estuary

Shellfish aquaculture is gaining acceptance as a tool to reduce nutrient over enrichment in coastal and estuarine ecosystems through the feeding activity of the animals and assimilation of filtered particles in shellfish tissues. This ecosystem service, provided by the ribbed mussel (Geukensia demissa), was studied in animals suspended from a commercial mussel raft in the urban Bronx River Estuary, NY, in waters closed to shellfish harvest due to bacterial contamination. Naturally occurring populations of ribbed mussels were observed to be healthy and resilient in this highly urbanized environment. Furthermore, mussels grown suspended in the water column contained substantially lower concentrations of heavy metals and organic contaminants in their tissues than blue mussels (Mytilus edulis) collected at a nearby benthic site. Spat collection efforts from shore and within the water column were unsuccessful; this was identified as a key bottleneck to future large-scale implementation. Filtration experiments indicated that a fully stocked G. demissa raft would clear an average 1.2 × 107 L of Bronx River Estuary water daily, removing 160 kg of particulate matter from the water column, of which 12 kg would be absorbed into mussel digestive systems. At harvest, 62.6 kg of nitrogen would be sequestered in mussel tissue and shell. These values compare favorably to other resource management recovery methods targeting agricultural and stormwater nitrogen sources.

Direct measurements of the nutrient management potential of ribbed mussels, Geukensia demissa, at two sites in upper Narragansett Bay, Rhode Island

Joint Meeting of the Northeast Aquaculture Conference and Exposition and the 35th Milford Aquaculture Seminar, 14-16 January 2015, Portland, Maine

An approach to study the feeding behavior of mussels in the field

S OF TECHNICAL PAPERS Presented at the 31st Annual MILFORD AQUACULTURE SEMINAR Milford, Connecticut February 7–9, 2011 Journal of Shellfish Research, Vol. 30, No. 2, 437, 2011.