Method of establishing clam bed colonies and mobile floating hatchery for implementing same

Abstract

A method for establishing a clam bed includes raising clam larvae in a captive environment in which they are provided with adequate food and habitat requirements, and kept isolated from predation by natural predators. The clam larvae are maintained in this environment during the first larval stage, referred to as the trochophore stage of development, when the larvae are particularly vulnerable to mortality. During the next stage of development, the larvae are called veligers. The developing larval clams are released, preferably in large numbers (saturation spawning) at any time during the veliger stage of development, i.e., the generic stage following the trochophore larval stage and which includes the sub-stages of straight-hinge veliger, umbonate veliger, and pediveliger. Preferably, the entire process prior to release in accordance with the invention is carried out in a closed system, to significantly reduce possible exposure to contaminants and/or harmful predator larvae/parasites, in addition to larger animal predators. A mobile floating hatchery/nursery facilitates implementation of the method by providing the captive environment, and allowing transfer of the veliger clams to a seeding site containing the prospective clam bed.

What is claimed is:  
     
         1 . A method of establishing a clam bed, comprising: 
 raising clam larvae through a trochophore stage of development in a captive environment; and    releasing the clam larvae into waters above an area selected to contain the clam bed during a veliger stage of development following the trochophore stage.    
     
     
         2 . A mobile floating vessel for containment and release of captive-raised clams into a wild environment, comprising: 
 a floatation housing movable through the water such that said floatation housing can be located at a seeding site intended for establishment of a clam bed colony; and    water holding tanks in which clam larvae are maintainable in a live state prior to release, a contents of the water holding tanks being ventable into waters upon which the flotation housing is floated.    
     
     
         3 . A method of introducing captive-bred fish into a wild environment, comprising: 
 providing a vessel for containment and release of captive-raised fish into a wild environment, comprising a floatation housing movable through the water and water holding tanks in which the fish are maintainable in a live state prior to release;    locating the vessel in a region of the wild environment suitably selected for repopulation with the fish; and    releasing a contents of the water holding tanks into the waters upon which the vessel is floating.