Ocean ranching is a type of fish farming in which juvenile fish are released into the ocean to grow unprotected and unassisted to be subsequently harvested (Thorpe 1980).
This definition clearly excludes mariculture conducted in pens or other enclosed and protected environments. In this report we will find it convenient to refer to this type of activity as simply ocean fish farming and the unassisted unprotected variety of ocean fish farming as ocean ranching. Both, however, belong to the set of ocean fish farming.
It may be noted that protection and assistance are, at least in principle, continuous variables that may range from zero (no protection and assistance) to very high levels (representing extensive protection and assistance). Ocean ranching is close to the zero end of this scale and ocean fish farming close to the high end as illustrated in the Figure below. The area in between represents variants that may be difficult to classify either as ocean fish farming or ocean ranching. For example imagine a collection of fish released in an open bay where they are occasionally fed at certain spots. As a result the fish tend to stay and do not swim off although they take much of their nourishment from the local ecosystem. Is this ocean ranching or ocean fish farming?
Scale of protection and assistance in mariculture
In this report, we take enclosure to be the demarcation between ocean ranching and ocean farming. This means that if the fish are not artificially enclosed, the activity is regarded as ocean ranching.
Proceeding on the basis of the above definition, ocean ranching appears to comprise two variants with quite different economic implications. The first is where the fish are intended for harvest (or other use) by the releasing agency itself. This is ocean ranching proper, quite similar to cattle and other animal ranching on land. In this report, we refer to this as pure ocean ranching. The second type of ocean ranching is where the fish are intended to be harvested by other agents unrelated to the releasing agency. This activity is essentially stock enhancement and will, consequently be referred to as stock enhancement ocean ranching in this report. It is of some importance to recognize that the concepts of pure and stock enhancement ocean ranching, just as ocean ranching and ocean fish farming are merely opposite poles on a spectrum of possibilities, and there are cases which are difficult to classify as one or the other.
This report deals with the economics of ocean ranching. It is primarily concerned with ocean ranching of the first type, i.e. pure ocean ranching. However, much of what is said also applies to stock enhancement ocean ranching which is specifically discussed when examining the ocean ranching experience of different countries.
The report is divided into three main sections. The first reviews the experience of ocean ranching in three countries; Japan, Iceland and the United States. The second section examines the fundamental externality associated with ocean ranching. Ocean ranching implies the addition of organisms into the marine environment. This, unavoidably, initiates ecological adjustments that generally lead to changes in the stock levels of many indigenous species some of which may be commercially exploited or otherwise valuable. In this way, ocean ranching inevitably has a fundamental external impact and this has to be taken into account when evaluating the economics of an ocean ranching project. The third section discusses a methodology for assessing ocean ranching projects.