小规模渔业中的非法捕捞是一个有争议的问题,并且拒绝直截了当的解释。特别是,关于合法和非法渔民之间的合作互动以及这些互动对渔业的潜在影响知之甚少。以智利帝王蟹(Lithodessantolla;俗称centolla)渔业为例,我们的目标是双重的:(i)模拟非法-合法渔民相互作用对渔业的影响;(ii)分析管理和社会行为如何影响渔业的结果。我们在博弈论与网络理论相结合的框架内对该问题进行了分析,以代表竞争互动的体系结构。渔民系统设置为包括注册(合法)渔民和未注册(非法)渔民。在未注册的渔民面前,合法渔民可以决定合作(忽略非法渔民的存在)或缺陷,这包括成为一名“超级渔民”,粉饰非法渔民的捕获以谋取利益。这两个玩家的效用,标准渔民和超级渔民取决于他们每个人选择的策略,以及非法渔民的存在。网络的节点代表合法渔民(标准和超级渔民),节点之间的链接表明这些渔民争夺资源,假设是有限的,并且在空间上均匀分布。考虑到渔民受到不同程度的诱惑来粉饰非法捕获以及停止这样做的社会压力,对改变(或不改变)所采用策略的决定进行建模。为了代表帝王蟹的生命动态,我们提出了一个模型,其中包括Allee效应和一个解释螃蟹提取的术语。我们发现,当存在以下情况时,超级渔民策略会导致帝王蟹种群减少,这是公地假设的悲剧:(i)由非竞争性标准渔民组成的网络的净提取率高,(ii)捕鱼季节的范围很高,和(iii)非法渔民的高密度。结果表明,即使存在超级渔民和非法渔民,选择适当分布的捕捞/封闭周期或设定每艘船的提取极限,可以防止帝王蟹种群下降到临界阈值以下。这个发现,虽然有争议,反映了这种渔业的现实,几十年来,在这种动态下运作,粉饰和超级渔民已经在系统内建立起来。
Illegal fishing in small-scale fisheries is a contentious issue and resists a straightforward interpretation. Particularly, there is little knowledge regarding cooperative interactions between legal and illegal fishers and the potential effects on fisheries arising from these interactions. Taking the Chilean king crab (Lithodes santolla; common name centolla) fishery as a
case study, our goal is twofold: (i) to model the effect of illegal-legal fishers\' interactions on the fishery and (ii) analyze how management and social behavior affect fishery\'s outcomes. We framed the analysis of this problem within game theory combined with network theory to represent the architecture of competitive interactions. The fishers\' system was set to include registered (legal) fishers and unregistered (illegal) fishers. In the presence of unregistered fishers, legal fishers may decide to cooperate (ignoring the presence of illegal fishers) or defect, which involves becoming a \"super fisher\" and whitewashing the captures of illegal fishers for a gain. The utility of both players, standard fisher and super fisher depend on the strategy chosen by each of them, as well as on the presence of illegal fishers. The nodes of the network represent the legal fishers (both standard and super fishers) and the links between nodes indicate that these fishers compete for the resource, assumed to be finite and evenly distributed across space. The decision to change (or not) the adopted strategy is modeled considering that fishers are subjected to variable levels of temptation to whitewash the illegal capture and to social pressure to stop doing so. To represent the vital dynamics of the king crab, we propose a model that includes the Allee effect and a term accounting for the crab extraction. We found that the super fisher strategy leads to the decrease of the king crab population under a critical threshold as postulated in the tragedy of the commons hypothesis when there are: (i) high net extraction rates of the network composed of non-competing standard fishers, (ii) high values of the extent of the fishing season, and (iii) high density of illegal fishers. The results suggest that even in the presence of super fishers and illegal fishers, the choice of properly distributed fishing/closure cycles or setting an extraction limit per vessel can prevent the king crab population from falling below a critical threshold. This finding, although controversial, reflects the reality of this fishery that, for decades, has operated under a dynamic in which whitewashing and super fishers have become well established within the system.