Why have sea creatures plummeted in size and number, if experts have at their disposal sophisticated techniques to count and predict them, whether tuna, cod, dolphin, or whale? This article conducts a literature review centered on a native category that dominates discourse in marine conservation—stock—by emphasizing the word’s double meaning as both asset and population. It illuminates how a word so commonplace enables the distancing metrics of numerical abstractions to be imposed on living beings for the production of biowealth. By tracking the rise of quantitative expertise, the reader comes to know stock as a referent long aligned with the sovereign preoccupation of managing wealth and society, culminating in the mathematical model recruited today as the principal tool of authority among technocratic elites. Under the prevailing conditions of valuation, the object of marine conservation has become not a fish as being but a biological asset as stock.