Today, the NEA stock is classified as having “full reproductive capacity” and being “harvested sustainably” [6] and [12]. Despite considerable attention Atezolizumab in vitro to the management of marine ecosystems, most fisheries have yet to be optimized to reach management goals [13], [14], [15] and [16]. Political obstacles and roadblocks play

an important role in failures of fisheries management [17]. Also, some scientific models for optimal management are not easily applicable to real-world situations, and may be based on hidden and/or overly simple assumptions [18]. Another obstacle for successful fisheries management is the fact that it is often not explicit, or evident a priori, which particular objectives should be pursued [16], [19] and [20]. At a very basic level, a specific fish stock can provide income to society, but also serves as an important food source. Therefore, Selleckchem BTK inhibitor one may favour a harvesting rate that provides the highest perpetual yield, known as the maximum sustainable yield (MSY), and this objective has been endorsed in various international agreements [19]. Economic science has added an important refinement to the purely biological consideration of MSY by accounting for the costs and benefits associated with resource extraction [21] and [22]. This allows deriving an exploitation path that maximizes profits from harvesting, but is based

on the simplifying assumption that the government, at least theoretically, is the “sole owner” of the resource. The contrast between these two basic approaches already shows that a crucial prerequisite for achieving optimal exploitation is the clear specification of management goals. A policy-maker may, for instance, take into account that parts of society are concerned about nature conservation in general, or about a specific species or ecosystem in particular. Accordingly, the policy-maker may decide to harvest less than what would be optimal if only yields or profits were to be maximized. The opposite can be true when fishing is considered part of a region’s Org 27569 cultural heritage, which society finds worth preserving even

at the expense of reducing profits through subsidies or over-fishing. It is important to acknowledge that fisheries management—just as every other part of public policy—is, inherently political. Nevertheless, objectives that politicians consider important should be clearly defined; otherwise, hidden objectives can sneak in through the backdoor and take precedence [18]. It is therefore desirable to devise models that are flexible enough to evaluate realistic political options and transparent enough to communicate their consequences effectively to all stakeholders. Technically, an HCR is a feedback control that links one or more control variables (e.g., catch) to one or more state variables (e.g., SSB) of the stock.