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Mathematical and statistical models underlie many of the world's most important fisheries management decisions. Since the 19th century, difficulty calibrating and fitting such models has been used to justify the selection of simple, stationary, single‐species models to aid tactical fisheries management decisions. Whereas these justifications are reasonable, it is imperative that we quantify the value of different levels of model complexity for supporting fisheries management, especially given a changing climate, where old methodologies may no longer perform as well as in the past. Here we argue that cost‐benefit analysis is an ideal lens to assess the value of model complexity in fisheries management. While some studies have reported the benefits of model complexity in fisheries, modeling costs are rarely considered. In the absence of cost data in the literature, we report, as a starting point, relative costs of single‐species stock assessment and marine ecosystem models from two Australian organizations. We found that costs varied by two orders of magnitude, and that ecosystem model costs increased with model complexity. Using these costs, we walk through a hypothetical example of cost‐benefit analysis. The demonstration is intended to catalyze the reporting of modeling costs and benefits. [ABSTRACT FROM AUTHOR]

Evolution is usually pictured as a tree where ancient species branch into new ones and eventually disappear. In this simplified view, the balance between speciation and extinction fully determines the diversity of life. Hybridization, however, introduces another level of complexity, allowing neighboring branches of the tree to interact, mixing their genetic content. This generates further diversity leading to reticulated trees. In this paper we study processes of speciation, extinction and hybridization using a genetically and spatially explicit neutral model of diversification. The model is based on the Derridaâ€"Higgs formulation, where the genome of haploid individuals is represented by binary strings and reproduction is constrained by genetic similarity. Tracking all events of speciation, extinction and hybridization throughout the evolutionary process allows us to compute complete and exact phylogenetic trees. We found that genome size played a key role in these processes, increasing the extinction rate and decreasing the hybridization rate. Only in the limit of large genomes the simplified picture of a branching tree is recovered. Most hybridization events occurred between relatively abundant species, discarding lack of sexual partners or small population sizes as potential causes. We found that hybridization occurred mostly because of opportunity (genetic similarity and spatial proximity) between recently branched species, when the number of accumulated mutations is not yet too large. [ABSTRACT FROM AUTHOR]