To Mr. Sandman,
Apparently you don't know anything about heavy metals in the ecosystem. They don't leave or metabolize. So if you think heavy metal levels in fish are better now than in the 60's, you are seriously mistaken. Fish are higher in heavy metals more than ever. Heavy metals bioaccumulate in fatty tissue. This means, as a fish feeds and increases with age, the level of contaminants increase over time. This same idea works with you. As you eat the fish, the contaminants that built up in the fish, bioaccumulate in you. Whether or not you care about the levels of heavy metals in your body is up to you. But, for someone like me who would eat a fish once a year and would like to have children some day, a fish much smaller than 36" would be much healthier for me and my future child. That is why some states have allowed fisherman to keep their one fish under 26". It is much healthier from a consumer standpoint. In Maine, we have consumption advisories specific to certain species and locations to inform people on how many meals are considered healthy to consume.
As for your genetics comment, Yes- If you remove large fish from the gene pool, you are eliminating large genes from the gene pool. If you are removing large genes from the gene pool, you are left with fish that do not have the genes to become large. That means the remaining fish overall average length is smaller.
