Design and construction of a low-impact amphibious vehicle for efficient and sustainable oyster farming

Near shore intertidal environments often present ideal conditions for cultivating shellfish, providing both the appropriate environmental conditions and reducing travel time and costs to access farms. However, the dynamic topographies of alternating sand bars and sloughs, tide-dependent work windows, and environmentally sensitive habitats characteristic of intertidal locations also present challenges to developing environmentally sound, optimal and efficient farm operations. Focusing their efforts during the low tide, many oyster farmers who operate intertidal farms have at best two hours on either side of a low tide to carry out daily husbandry and harvest tasks. This limited period heightens the need for equipment and practices that maximize efficiency while minimizing environmental impacts. A critical problem is the lack of a low impact versatile vehicle that allow oyster growers to efficiently transport oysters and gear to and from, and within the farm, and provide a platform for production activities, such as harvesting and sorting stocks. The purpose of this project was to design, build, and evaluate an Amphibious Farm Vehicle (AFV) customized for working an intertidal oyster farm.  Central to the design was the desire for the vehicle to be low impact—quiet and environmentally friendly. The resultant manually operated AFV has increased the efficiency of farm operations, while minimizing environmental impacts on a small scale oyster farm in the lower Delaware Bay, NJ.

Using it were able to maximize our work time on the farm, increasing our typical field season workday by 25-30%. This resulted in decreasing the number of days we needed to be on the farm greatly saving in labor costs and travel time and costs associated with driving to and from the farm site, an estimated savings of $4,176 per year ($54 travel savings and $120 labor savings per week for 24 weeks).  The work platform (deck mounted surface and removable table) provided ample and comfortable work surface for up to six workers.

A formal outreach presentation and demonstration was conducted on December 21, 2015 at the Rutgers Cape Shore Laboratory as part of the University’s Shellfish Growers’ Forum program.

Introduction:

Many oyster farms in the United States are located in inter-tidal zone, near shore areas that are covered at high tide and exposed at low tide. While offering benefits, such areas also provide many challenges for the oyster farmer. Dynamic topographies of alternating sand bars and sloughs, tide-dependent work windows, and environmentally sensitive habitats create challenges when developing environmentally sound, optimal and efficient farm operations. Focusing their efforts during the low tide, oyster farmers who operate intertidal farms have at best two hours on either side of a low tide to carry out daily husbandry and harvest tasks. This limited period heightens the need for equipment and practices that maximize efficiencies while minimizing environmental impacts. A critical problem is the lack of a low impact versatile vehicle that allow oyster growers to efficiently transport oysters and gear to and from, and within the farm, and provide a platform for production activities, such as harvesting and sorting stocks.

Inter-tidal oyster aquaculture represents an important segment of the oyster industry in New Jersey, Massachusetts and elsewhere. In New Jersey the nucleus of a growing oyster aquaculture industry is situated on the extensive intertidal areas of the lower Delaware Bay (Cape Shore).

The intertidal oyster farms are situated in sloughs and on sandbars. Some growers, particularly those operating larger scale farms, use all terrain vehicles (ATV’s) to pull small wagons to transport aquaculture gear and oysters. Smaller and entry-level farmers tend to use wheel barrels and/or small-size shallow drafted flat bottom boats. These existing methods were not designed for the purpose of oyster farming and have several disadvantages. ATV’s are expensive, subject to rapid corrosion and decay in the marine environment, having only a 2-5 year usable life span and potentially adversely effect the environmental via noise, fuel consumption and potential for spillage, and relatively heavy trampling on benthic estuarine habitat and organisms. Moreover, the potential disturbance of threatened migratory shore birds and their critical habitats by aquaculture has risen as a principal concern for federal and state regulators who are charged with permitting aquaculture activities. The recent Endangered Species listing of the Red Knot, Calidris canutus,whose migratory pathway overlaps with Delaware Bay farm areas, has called into question ATV use and elevates the need to minimize potential impacts of farm vehicles on migratory shorebirds and their habitats. Operation of wheel barrels and small boats has low environmental impact but is cumbersome, requiring multiple trips from shore due to limited haul capacity, and as such are only suited for very small operations. Furthermore, desired transit times driven by daylight and variable tides may be mismatched with water level, resulting in the need to drag boats across sand bars or float destabilized wheel barrels.

The project was a collaborative effort of Gustavo and Lisa Calvo, Sweet Amalia Oyster Farm; David Bosco, Bosco Architects; Dan Dutra, Dutra Sheet Metal Co.. Daphne Munroe, Haskin Shellfish Research Laboratory of Rutgers University served as the project’s Technical Advisor.

Architect and builder David Bosco, Newfield, NJ specializes in design/build project delivery methods in addition to full architectural design services for the commercial, industrial and residential markets. For additional information see http://boscoarchitects.com

Fabricator Dan Dutra, Dutra Sheet Metal, Co. (DSM) of Vineland, NJ offers a wide range of services to a diverse clientele. In addition to fabricating ductwork for the commercial construction industry, he has experience designing and constructing equipment for the many local farms, glass houses and food processing plants. The projects range from one of a kind prototyping, modifications to existing equipment systems, as well as design and construction of new and innovative equipment.

Dr. Daphne Munroe is an Assistant Professor at the Haskin Shellfish Research Laboratory, Rutgers University. An expert in the area of marine biology, Dr Munroe has 14 years of experience conducting research on shellfish aquaculture and benthic ecology.

Sweet Amalia oyster farm is a small family farm established on the Cape May Peninsula in 2012. The farm with a target annual production of 200,000 oysters per year employs rack and bag grow out system, producing half shell market oysters for direct delivery. The farm originated in Mobjack Bay, Virginia where it operated from 1999-2004. Environmentally responsible and sustainable farm practices are at the heart of the farm’s business model.

Initial collaboration began at examining our farm’s day-to-day operations and means of equipment/gear organization and available modes of transportation. Recognizing that there was a vast potential for improvements, the team developed a criteria to design and build an innovative, nimble, versatile, and low impact amphibious module to serve as transport and working platform with a goal to establish a more sustainable and efficient operations of inter-tidal and shallow sub-tidal oyster farming.