They can accidentally catch dolphins, turtles, even orcas. Greenpeace is actively trying to get them banned.
Nitrogen,<span>The atmosphere is composed of ~78% nitrogen and ~21% oxygen, with small amounts of other gases. The bulk composition of the earth by weight is mostly, iron, oxygen, silicon and magnesium, in that order, with all the other elements making up only about 5% of the earth's weight.</span>
Retinol is the form of vitamin A that causes the greatest concern for toxicity.
Hope this helps!