原句是That means a higher proportion of what is in the sea is being caught, so the real difference between present and past is likely to be worse than the one recorded by changes in catch sizes.

请问recorded by changes in catch sizes该怎么理解?

如果理解成“捕捉规模的变化所记录的……”，那为什么这里用by不用of？ by在这里是什么意思？