Hello Kamel! Welcome to Speardiver! And welcome to the UAE!
I'm relatively new to Speardiver as well. You'll find that this forum is THE best spearfishing forum there is! :thumbsup2:
I live in the UAE as well, in Sharjah (very close to Dubai). In fact, many spearo's hunt in Sharjah, Ajman and neighboring emirates due to the ongoing artificial island construction off the shores of Dubai.
The viz here in the UAE (Persian gulf coast) is not too great, but in the winter, it could open up to around 30-40 feet at times.
Due to the Viz, the most used speargun size varies from 80cm to 110cm. Some Spearo's also use 120cm and above for wreck diving from a boat.
Compared to the Mediterranean, The 'fishy' depths are relatively shallower here. In fact, you can find nice Snappers and Groupers in less than 10 metres depth! In this case, the hazy viz is an advantage! Due to the scarcity of natural underwater structure in the Arabian/Persian gulf, a lot of fish congregate at man made breakwater rocks. So shore diving is fairly simple!
Sharks are not an issue on this coast (or so I've heard), but be VERY wary of Jetski's and boats. Every other douchebag has a jetski here. And sometimes if they see you, they'll take that opportunity to splash water at you whilst coming within 2 feet of you! They have NO sense of personal responsibility!
There are no clear rules for spearfishing in the UAE. Abu Dhabi is off limits for spearin', but some spearo's go there anyways. Dubai is also a little unclear on SF regulations. Some spearo's have been approached by the coast guard whilst spearing in Dubai, and if the coast guard is in a bad mood, say goodbye to your equipment!:( This is never an issue in Sharjah, Ajman, Um Al Quwain, or RAK. The coast guard dont really bother anyone in these emirates.
The EAST COAST of the UAE (Fujairah and Khorfakkan) is a different ballgame altogether! It's the Indian ocean, and the depths and viz are MUCH better. There's a lot of natural structure, and the viz is excellent! However, a majority of this area is a protected marine reserve, and the coast guard is very vigilant there! It's a fun place to go for a swim/snorkel/dive, though.
There are many different species of fish to hunt here. The most popular fish in the UAE is the Arabian Grouper (or "Hammour"), and you'll find a few of them here hiding near the rocks. You'll find other reef fish such as Longnose emperors, Snappers, Sweetlips, different types of trevallies and different types of sea breams.
During the cooler months (September to March), you would be able to see some King Mackerel (or "Kanaad"), Queenfish, Barracuda, and even cobia if you're lucky!
You can PM me for details on stores and dealers of spearfishing equipment.
Hope you enjoy it here! It's a hot country, but there are a lot of activities to "beat the heat", so to speak.