连接: 管理渔业

As the population of the world has increased rapidly, the demand for fish to consume has risen as well. This combined with increased technological abilities has led to overfishing, a situation in which there is so much fishing that the population of fish begins to decline ¹ . In economics, overfishing would be an example of what is known as the tragedy of the commons, a situation with a shared resource where individuals acting in their own self-interest act contrary to the common good for all users ² . In some areas, overfishing has caused the population of fish to decline to such an extent that catching certain types of fish has been outlawed. 
::随着世界人口的迅速增长,对鱼类消费的需求也随之增加,再加上技术能力的提高,导致过度捕捞,目前的情况是捕捞量大到鱼量开始下降。 1 在经济方面,过度捕捞将是一个例子,说明所谓的公域悲剧,一种共有资源的情况,即个人以自己的私利行为违背所有使用者的共同利益。 2 在一些地区,过度捕捞已导致鱼量下降,以致非法捕捞某些种类的鱼。

To address this problem, groups or authorities can establish a fishery—a place where fishing is allowed and/or fish are raised to be harvested.
::为解决这一问题,各团体或当局可以建立一个渔业——一个允许捕鱼和(或)捕捞鱼类的地方。

Within a fixed area of water, fish have a limited number of resources, like space and food. This limits the number of fish that can live in the space. This limit is known as the carrying capacity ^1,3 . 
::在固定水域内,鱼类拥有有限的资源,如空间和食物,这限制了能够生活在空间内的鱼类数量,这一限制称为承载能力1 3。

1. The population of one type of fish in a certain area can be compared to the growth rate of the population of fish in that area using the model  $\begin{array}{r}g=\text{-}0.00001(p-200,000{)}^2+150,000\end{array}$ . Graph this function.
::1. 使用模型g=-0.0001(p-200 000)2+150 000,可以比较某一地区一种鱼类的种群与该地区鱼类种群的增长率。

2. The carrying capacity is the population when the growth rate is 0. Find the carrying capacity of this population.
::2. 承受能力是指增长率为0时的人口。 找到这一人口的承受能力。

3. When the population is 100,000 fish, how many fish should the fishing boats catch to allow the population to continue to grow? Compare numbers caught to the growth rate.
::3. 当人口为10万鱼时,渔船应捕多少鱼才能使人口继续增长?与所捕量的增长率相比。

4. To avoid overfishing, groups should not catch fish when the population is low. The maximum amount of fish they should catch is the maximum of the function. This point is known as the maximum sustainable yield. Find the maximum sustainable yield for this situation.
::4. 为了避免过度捕捞,各群体不应在人口少时捕鱼,他们应捕获的最大鱼量是最大功率,这一点称为最高可持续产量,为这种情况找到最高可持续产量。

Since this is a business for the fishing boats involved, let's look at a revenue function. We can compare revenues to what is known as "the fishing effort," a quantity that represents many factors, including how many boats are fishing in the area, how long the boats are fishing, and how technologically advanced the boats are. For this area and type of fish, the model is  $\begin{array}{r}R=\text{-}(e-5{)}^2+900\end{array}$ , where $\begin{array}{r}R\end{array}$  is in thousands of dollars. 
::由于这是有关渔船的生意,让我们看看一个收入功能。我们可以把收入与所谓的“捕鱼努力”作比较,这个数量代表许多因素,包括该地区有多少渔船在捕鱼,渔船在捕鱼多久,以及渔船在技术上有多先进。对于这个区域和鱼类来说,模型是R=-(e-55)2+900,R是数千美元。

5. Graph this function. The vertex of this function represents the maximum sustainable yield in terms of effort and revenue. Find the maximum sustainable yield. 
::5. 绘制本功能图:本功能的顶点代表努力和收入的最高可持续收益率,找到最高可持续收益率。

6. The costs for fishing boats in this area can be modeled by $\begin{array}{r}C=100e,\end{array}$  where $\begin{array}{r}C\end{array}$  is in thousands of dollars. Graph this function on the same set of axes as your revenue model.
::6. C=100e可以模拟这一地区的渔船费用,C=100e以千美元计,将这一功能与你的收入模式放在同一套轴上。

7. The maximum economic yield is the point at which the revenue graph is different from the cost graph by the largest amount. Approximate the maximum economic yield. How does this differ from the maximum sustainable yield?
::7. 最大经济收益率是收入图表与成本图表按最大数额分列的差异点,与最高经济收益率相近,这与最高可持续收益率有何不同?

8. Find the break-even point for this situation. Should this be the amount of effort that boats are allowed to fish at?  
::8. 找到这种情况的平衡点,这是否应是允许船只捕鱼的力度?

by Conservation Strategy Fund shows how to find these models relate to one another . 
::养护战略基金说明如何发现这些模式相互关联。

References
::参考参考资料

1. "Fisheries Management," last edited May 23, 2017,
::1. 2017年5月23日 上次编辑的《渔业管理》

2. "Tragedy of the Commons," last edited May 10, 2017,
::2017年5月10日,

3. "Population Dynamics of Fisheries," last edited February 23, 2017,
::3. “渔业人口动态”,2017年2月23日编辑,