Of course, there is no 'right' answer. Whether anything is justifiable is a function of the priorities and biases of whomever is doing the asking .... and being asked. Frankly its the wrong question. Most hobbies, including sports, would fail to meet the 'justifiable' standard given the consumption of resources. The better question is whether the reef hobby is sustainable or not - really the same question that is asked of the food fishing industry (though, of course, that's on a whole different scale). Sustainability has come to be synonymous with the environment, and that's a factor, but ultimately sustainability is about whether an activity, any activity, will deplete its attendant resources to the point were those resources will be permanently injured. So, does our hobby unsustainable deplete naturally occurring stocks of fish, corals or other invertebrates (on a broader level, the ethics of whether we should be collecting those animals is irrelevant - nature simply doesn't care about individuals, is the species survival that is important)? Certainly as hobbyists, we should decry certain practices. I will not knowingly buy a fish from an area that is known to still employ cyanide, for example.
So, is our hobby sustainable? I'd argue in and of itself, yes, it is sustainable. Trouble is that it is no longer possible to separate the impact of our hobby from that of the cruise industry, or acid rain, or warming oceans. Natural reefs are declining, and should be protected. I'd support legislation to prohibit the collection of any species that is considered to be threatened or endangered, but for that legislation to also prevent resourceful hobbyists from propagating and then selling small frags seems foolish. That is what, as an industry, we should be objecting to, and asking for common sense in the legislation.
