这一段请教一下大家语义实在不懂

Gmaaa700+

Proponents of theory A dispute the assumption that
a school of thousands of fish is highly visible.
Experiments have shown that any fish can be seen,
(10) even in very clear water, only within a sphere of
meters in diameter. When fish are in a compact group,
the spheres of visibility overlap. Thus the chance of a
predator finding the school is only slightly greater
than the chance of the predator finding a single fish
(15) swimming alone. Schooling is advantageous to the
individual fish because a predator's chance of finding
any particular fish swimming in the school is much
smaller than its chance of finding at least one of the
same group of fish if the fish were dispersed
(20) throughout an area.

之前说了基本所有的鱼都是成群结队，A的假设是很多的鱼在一起可见度很高

后面又说道，捕食者发现一群鱼的机会 仅比 发现一条鱼的机会大一点点。 下一句又说成群结队有利于单独的鱼，因为发现鱼群的机会更大？？？

这里逻辑一直没有读通，求高手指教

T7willG700

Proponents of theory A dispute the assumption that a school of thousands of fish is highly visible. A的假设是很多的鱼在一起可见度很高 读错了喔, As Ron said, you have to read it really literally
A理论的支持者DISPUTE了[很多的鱼在一起可见度很高]这样一个assumption

Experiments have shown that any fish can be seen, even in very clear water, only within a sphere of meters in diameter. When fish are in a compact group, the spheres of visibility overlap.
为什么dispute？因为实验结果显示可见度并不高

Thus the chance of a predator finding the school is only slightly greater than the chance of the predator finding a single fish swimming alone.
后面又说道，捕食者发现一群鱼的机会 仅比 发现一条鱼的机会大一点点✔
得出结论predator找到鱼群的概率并不高

Schooling is advantageous to the individual fish because a predator's chance of finding any particular fish swimming in the school is much smaller than its chance of finding at least one of the same group of fish if the fish were dispersed throughout an area.
下一句又说成群结队有利于单独的鱼，因为发现鱼群的机会更大？？？
这句读错了 所以理解错
意思是predator找到一个鱼群的概率是小于找到鱼不结群而是分散开的情况下单独的鱼


Hope that makes sense : ）