Reefer....you can find out anything you want to know about fishing on Ambergris Caye including tackel info at this address.... //ambergriscaye.com/pages/town/fishing.html
As far as renting a kayak and fishing the flats. the kayaks are rented on the east side or reef side of the island. I wouldn't call this area flats though. Although it is fairly shallow and Barracuda are frequently caught....it's probably not what your thinking. Therefore...you would have to kayak to the lagoon area....via the cut...and then out into the lagoon where Tarpon are alive and well. There is also superb shallow fishing in the north areas of the island.....i.e., Punta Azul, Basil Jones beach, Roble's Point and Rocky Point areas.
Bonefishing is really good in these locations. Only problem is....it's at least about 12 miles north from San Pedro.
If you really want to catch fish....I would forget the kayak...and go on a boat with a guide.....you won't be disappointed! They can even arrange to have a beach BBQ and cook your catch of the day for you. Makes for a nice day!
Judging from the size of the Tarpon I've seen here....LOL....I don't think I'd want to spear it.....could get nasty!....LOL
I'm sure it's been done before though....people will try anything here..LOL.
Oh yes...one more thing....if you do decide to kayak around to the lagoon side.....please don't go wandering thru all the little mangrove lanes to the backside.
Local people rarely go back there....and none of the areas are marked. You can get lost in there in about 2 seconds. A guest from one the resorts north of the cut did get lost one time....ventured out on his own....they didn't find him for 3 days. Happy to report he was alright....but not happy about loosing 3 days of his vacation...and VERY thirsty!
visit BELIZE WORLD! http://www.geocities.com/sanshakr.geo