Evolution of harvesting strategies: replicator and resource dynamics

Abstract. Economic theories of managing renewable resources, such as fisheries and forestry, traditionally assume that individual harvesters are perfectly rational and thus able to compute the harvesting strategy that maximizes their discounted profits. The current paper presents an alternative approach based on bounded rationality and evolutionary mechanisms. It is assumed that individual harvesters face a choice between two harvesting strategies. The evolution of the distribution of strategies in the population is modeled through a replicator dynamics equation. The latter captures the idea that strategies yielding above average profits are demanded more than strategies yielding below average profits, so that the first type ends up accounting for a larger part in the population. From a mathematical perspective, the combination of resource and evolutionary processes leads to complex dynamics. The paper presents the existence and stability conditions for each steady-state of the system and analyzes dynamic paths to the equilibrium. In addition, effects of changes in prices are analyzed. A main result of the paper is that under certain conditions both strategies can survive in the long-run. Correspondence to: J. Noailly     

Sushi or Fish Fingers? Seafood Diversity,Collapsing Fish Stocks,and Multispecies Fishery Management*

We present a model of a multispecies fishery, and we show the following. (i) Consumer preferences for seafood diversity can trigger a sequential collapse of fish stocks under open‐access fishery. (ii) The stronger the preferences are for diversity, the higher is the need for coordinated multispecies regulation. (iii) Second‐best optimal management of only one (or a few) species is less strict than socially optimal management of the same species. (iv) Myopic regulation of one species, ignoring spillovers to other species, can cause depletion of other stocks that would not be depleted under open access.     

我国水产种苗发展存在的问题与对策

改革开放以来，我国水产种苗行业虽然取得了很大进展，但与实际需要还很不适应。今后应加大投入，努力完善水产种苗生产体系、管理和质量监督体系、科研体系，促进我国水产种苗稳定、快速和健康发展     

How did a network of marine protected areas impact adjacent fisheries? Evidence from Australia

Marine‐protected areas (MPAs) are an effective means of improving habitat quality and biodiversity in the world’s oceans. While the advantages of MPAs as a mechanism for conservation and biodiversity are well established, the potential improvements to fishery performance resulting from a network of MPAs are still being established. Countries around the world have committed to establishing networks of MPAs within their waters by 2020, in response to the United Nations Convention on Biological Diversity. This, coupled with the increasing global demand for seafood and heavy reliance on fishery resources as a source of economic development for many coastal communities, means that an understanding of how these networks can be expected to impact fishery performance is extremely important. We use a difference‐in‐difference modelling approach to isolate the change in the fishery performance associated with the south‐east marine reserve network in Australia. We find no evidence that the economic performance of adjacent fisheries was negatively impacted by the network. This lack of impact is likely due to a network design explicitly intended to avoid effort displacement in key fisheries, along with fishery management changes intended to remove excess fishing capacity.     

Effectiveness of harvest strategies in achieving multiple management objectives in a multispecies fishery

Fisheries management is characterised by multiple objectives, some of which may be complementary, while others may require trade‐offs between outcomes. Balancing these objectives is made more complex in the case of multispecies and multigear fisheries. In this paper, we develop a bioeconomic model that captures the key elements of such a fishery to test a range of potential harvest strategies to provide insights into how economic target reference points could lead to both desirable and undesirable management outcomes (e.g. discards). The model is developed as a long‐run optimisation model to identify target reference points to achieve multispecies maximum economic yield, and a dynamic recursive optimisation model, which includes more realistic representation of fishers’ behaviour, such as discards and trading of under‐caught species quotas. The potential economic, social and ecological impacts are evaluated using data envelopment analysis (DEA). The results suggest that the use of proxy target reference points can result in short‐term economic benefits at the cost of slower stock recovery and higher discarding. Limiting the number of species subject to quota controls may also prove beneficial in multispecies fisheries, while ensuring quota markets are efficient is likely to produce benefits irrespective of the harvest strategy adopted.     

福建省水产业二十年改革与发展

改革开放２０年来,福建省水产业有了突飞猛进的发展。主要经验：一是解放思想、开拓思路;二是改革渔业经济体制;三是实施科教兴渔;四是扩大国际交流与合作;五是加强法制建设     

关于渔业产业化问题

本文指明了渔业产业化的实质所在，分析了渔业产业化水平的现状，并联系渔业产业化实践提出了建设性的思路，以供进一步研究提高渔业产业化问题时参考     

我国渔业现代化程度及发展前景

本文认为中国正在缩小同世界发达国家在渔业现代化上的差距。在生产上,已建立了世界上规模最大的水产养殖、捕捞体系;在科学技术上,某些方面接近或达到了世界先进水平;在物质装备上,已基本达到世界中等水平。由市场经济造就出来的多种经济形式的渔业大中型企业及企业集团,正在以强劲的实力,成为我国渔业现代化的中坚。随着国民经济的持续、健康发展,我国渔业综合生产能力将进一步提高,渔业现代化建设将得到继续增强,从而尽快进入渔业现代化的先进行列     

我国沿海渔民转产转业问题的成因分析

我国沿海渔民转产转业的直接成因是因三大双边渔业协定的签订实施而导致的传统渔场压缩,但其共同的原因则是技术进步、环境污染及过度捕捞所引起的渔业资源衰竭,而造成渔业资源过度利用的深层原因则是海洋渔业资源的共有财产特性及海洋渔业的自由准人机制,其核心是产权问题.     

《中韩渔业协定》的实施对辽宁省渔业的影响及对策

《中韩渔业协定》实施后,由于作业海域、船数、时间、方式及渔获物配额等方面的限制,对辽宁省的渔业管理体制产生极大的冲击,给广大渔民的生产、生活和经济发展及社会稳定增加了许多问题和矛盾,本文就《中韩渔业协定》的实施对辽宁省渔业的影响及对策作一简单的探讨。