Mailing abalone huh?
I sort of wondered why anyone would bother, but I guess legally harvested wild red abalone are freaking huge - big enough for abalone steaks. I believe the legal minimum is 7 inches across for sport harvesting. I've seen farmed red abalone, and the size is typically 3 inches and sometimes 5 inches (sold at a premium). They tend to grow quickly to 3-4 inches within a couple of years and take considerably longer to reach 7 inches (I understand up to 12 years). Still - farmed abalone isn't even that expensive. I've seen it for $20/lb which might yield 4-5 of the 3 inch ones.
I've seen some large red abalone (very much alive) that I suspect was illegal sold and possibly even poached. I've heard of some operations using breathing apparatus to make it easier to reach the bigger abalone at deeper depths without having to come up for air. They can pick clean dozens of abalone in some areas in less than an hour, while legal harvesting is limited to 3 per day.