They specifically did not do that. The court tracked down the origin of this change in the definition of the law, and the legislature at the time was acting in part to preserve an endangered terrestrial snail. If they'd meant "aquatic invertebrates", that's what they'd have said.

They already stated that the snail was a mollusk. It still seems you're ignoring the context of the fact that they added invertebrates under the fish heading, while they added other classes (plants) under their own headings. That context seems to indicate aquatic relation. Perhaps it was just them being lazy, but it would have been more proper to have it as it's own classification as was done for plants. This whole thing would have been unnecessary if they were good at being lazy and said they had the power to regulate species without making all these classifications.

This snail is a terrestrial mollusk, so that doesn't help you. But even if it did: the legislature was also trying to protect 3 different butterflies along with the snail. I don't think there's a way to weasel out of this.