Although California produces some oyster seed for local growers, its shellfish farms rely heavily on seed from the state of Washington. This has been a good business arrangement for both growers and hatcheries, but their future was threatened in 2002 when two wild Pacific oysters from Washington’s Dungeness Bay were found to be infected with the pathogen Mikrocytos mackini, the causative agent of Denman Island disease. The disease poses no human health risk, but in oysters it can cause unsightly green or yellow pustules, rendering the animals commercially worthless.

The goal of this project was to investigate and document the presence of disease agents in cultured and wild oyster populations throughout California. This is the first comprehensive survey to be conducted since that of Katkansky and Warner in the late 1960s to early 1970s (Katkansky and Warner, 1974). Particular emphasis was placed on detection of the agent of Denman Island Disease (Mikrocytos mackini, Farley et al., 1988). This pathogen of the Pacific oyster (Crassostrea gigas) was detected in the State of Washington in 2002, and many California oyster growers receive seed from Washington State. All major populations of farmed and feral commercial oysters and wild native oysters Ostrea lurida were targeted for sampling. Sufficient numbers from each population were collected so that relatively rare pathogens should have been detected when they are present.

Introduction

Case presentation

Conclusion

Sea Grant research has led to the development of a cure for an abalone wasting disease that destroyed about $1.5-million worth of farmed abalone product at two California farms during the1997–98 El Niño. The antibiotic therapy is now being used to help in the restoration of endangered wild white abalone on the U.S. West Coast.

Withering syndrome is a chronic, often fatal disease of multiple species of California abalone. It was first observed in the mid-1980s at the Channel Islands off Southern California and has since spread along the main coastline as far north as the San Francisco bay area. Recent research has demonstrated that the causative agent is a Rickettsiales-like prokaryote (WS-RLP, Friedman et al. 2000), and that WS expression is much more rapid and severe at elevated water temperatures (Moore et al. 2000). Aside from impacts on wild populations, WS has resulted in substantial losses in red abalone farms. As a result of these losses and our observation that the WS-RLP is sensitive to tetracyclines, we developed and oral administration of oxytetracycline in conjunction with researchers at The Abalone Farm, Inc.

This report presents the Conceptual Design Plan for evaluating the effectiveness of the Smart Corridor Demonstration Project. The specific objectives of this report are to: 1) develop a conceptual structure for the Smart Corridor evaluation, 2) define evaluation data requirements and collection procedures, and 3) select and/or develop data reduction and data analysis methodologies. Overall, the Smart Corridor is designed to obtain improved utilization of existing roadway facilities, both freeway and arterial, through the use of Advanced Traveler Information Systems ( ATIS) and Advanced Traffic Management Systems (ATMS), through improved inter-agency coordination, and through better use of conventional traffic management strategies.

Transportation systems are spatially distributed systems whereby components of the system are exposed to different ground effects due to the same earthquake event. The ground effects that various components of the system are subjected include ground shaking, vertical displacements due to settlement, and horizontal displacements due to lateral spreading and sliding. The ground displacements occur because severe ground shaking causes liquefaction and landslides under the appropriate environmental conditions. Bridges are key components of transportation systems and are particularly susceptible to liquefaction and landslides as they are located over streams and rivers with piers situated over sandy saturated deposits; or they may be over canyons with high slopes that may result in slope instability. Thus, it is important to integrate the effect of local site conditions in the overall earthquake risk of a transportation system.

Consideration of the spatial dependence of individual components is an important factor in the evaluation of the network system connectivity and traffic flow through the system. Risk assessment methods require that not only the component performance is assessed, but the overall system performance is evaluated. Most recently, Werner et al. (2000) and Basoz and Kiremidjian (1996) considered the problem of transportation network systems subjected to earthquake events. In both of these publications, the risk to the transportation system is computed from the direct damage to major components such as bridges and the connectivity between a predefined origindestination (O-D) set. Basoz and Kiremidjian (1996) also consider the time delay and use the information primarily for retrofit prioritization strategies. The current software HAZUS (1999) for regional loss estimation developed by the National Institute for Building Standards (NIBS) for the Federal Emergency Management Agency (FEMA) considers only the direct loss to bridges in the highway transportation network. The connectivity and traffic delay problems resulting from damage to components of the system are not presently included in that software. Chang et al. (2000) propose a simple risk measure for transportation systems to represent the effectiveness of retrofit strategies by considering the difference in costs associated with travel times before and after retrofitting.

In this article, a method for risk assessment of a transportation system is postulated that considers the direct cost of damage and costs due to time delays in the damaged system. The method is applied to the transportation network within five counties in the San Francisco Bay Area and conclusions are drawn on the basis of the application. The site hazards considered in the direct loss estimation include ground shaking, liquefaction and landslides. The effect of bridge damage from ground shaking hazard on the transportation network is studied under the assumption that traffic demand following the earthquake is either constant or variable.

The white abalone , Haliotis sorenseni, supported valuable commercial fisheries only 30 years ago. In 2002, this species became the first marine invertebrate in the United States to achieve federal endangered species status. The overall goal of this project was to collect life history, genetic and disease susceptibility data that to support recovery.

Withering syndrome (WS) is a catastrophic disease of both wild and cultured abalone caused by “Candidatus Xenohaliotis californiensis”, a Rickettsia-like procaryote (WS-RLP). Losses from this disease have severely hampered the abalone aquaculture industry and abalone restoration efforts in California. Oxytetracycline (OTC) was recently demonstrated to be an effective therapeutant for WS-RLP infections and associated losses due to WS. In addition, a long duration of protection (approximately one year) was noted anecdotally. Part one of this study examined the efficacy and pharmacokinetics of OTC treatment in red abalone, Haliotis rufescens, held at 13.4oC. Medication was administered orally in an artificial diet containing 1.85% active OTC at a rate of 103.4 mg/kg abalone for 10, 20 and 30 days. Control abalone were fed the same diet lacking OTC. Significant differences in prevalence and intensity of infection in both the post-esophagus and digestive gland were observed. Although the digestive gland from abalone medicated for 10 days and foot muscle from those medicated for 30 days was best described with a two-compartment model, pharmacokinetic trends were adequately described by a one-compartment model. Significant differences in OTC accumulation and depletion were observed among treatments. Animals medicated for 10 days accumulated significantly less than those medicated for 20 or 30 days. Despite this, terminal elimination rate constants were similar. Significantly less OTC was present in foot muscle samples relative to corresponding digestive gland samples. Estimated half-life values were similar among treatments for both foot muscle (10.7-13.4 d) and digestive gland (23.8-27.5 d) samples.