As a keen SA snapper fisher, I can tell you from personal experience that snapper numbers are WAY WAY down.... and I dont fish Gulf St Vincent.
Where I would get 4-5 reasonable snapper around 45cm (and a fair bit of quality by-catch) fairly easily on my irregular outings (6 times a year?) , the last 2 years have 4 total! The last time I went about 2 months age, no snapper and no bycatch for around 6 hrs on the water-- didnt even lose a bait to a fish.
I think 'threatened' IS the correct word to use.