Two fish species competition model with nonlinear interactions and equilibrium catches
Two fish species competition model with nonlinear interactions and equilibrium catches
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DOI：
10.1007/bf02512979
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发表时间：
1978-09
期刊：
影响因子：
--
通讯作者：
K. Shirakihara;Syoiti Tanaka
中科院分区：
文献类型：
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作者：
K. Shirakihara;Syoiti Tanaka
为了考虑开发对两个具有非线性相互作用的竞争鱼类种群的影响，通过假设两种鱼类之间存在二阶相互作用，建立了两种鱼类竞争模型。与Lotka-Volterra型线性竞争模型相比，该模型最重要的特点是具有多个稳定平衡点。因此，在一个稳定平衡点上保持平衡状态的两个种群在受到较大扰动后，有可能被吸引到另一个稳定平衡点上，在该模型中，捕捞压力的可逆变化并不总是导致平衡渔获量的可逆变化。在这个意义上，单物种的MSY概念不能扩展到这个模型。如果存在多个稳定平衡点，则当增加开发扰动时，可能会出现优势鱼种的变化，以及各平衡渔获量的灾难性和不可逆的变化。这一现象立即提醒我们注意西北太平洋日本鲭鱼和秋刀鱼之间的优势鱼种的变化，在管理两种竞争性鱼种的非线性相互作用的情况下，考虑各鱼种捕捞压力之间的平衡可能与决定各鱼种的捕捞限额同样重要。基于单种理论的每个种属的MSY水平可能非常错误。
Two species competition model is built up by assuming the hypothetical second order interactions in order to consider effects of exploitation on two competing fish species with non‐linear interactions. Most important characteristic of this model, compared withLotka‐Volterratype linear competition model, is that this model can possess multiple stable equilibrium points. Therefore there is a possibility that two species keeping the equilibrium state at one stable equilibrium point will be attracted to the other stable equilibrium point after a heavy perturbation.In this model reversible change of the fishing pressure does not always results in that of the equilibrium catch. In this sence MSY concept for single species can not be extended to this model. If there are multiple stable equilibrium points, the change of the dominant fish species, catastrophic and irreversible change of each equilibrium catch may be observed when the perturbation by the exploitation is added. This phenomenon immediately reminds us of the change of the dominant fish species between Japanese common mackerel and Pacific saury in the northwest Pacific Ocean.In case of the management of two competing fish species with nonlinear interactions, the consideration on the balance between the fishing pressure for each species may be as important as the decision on the catch limit for each species. MSY level for each species based on the single‐species theory could be quite erroneous.