It is more likely to catch fish like that on float and bread:

There is big fish around in December but it requires a lot of local knowledge, luck, nice weather and expensive gear for shore jigging and spinning.
You can catch big fish on the bottom at night if you find the right spot.
My personal experiance is that one week holiday fishing is more likely to produce the fish from the photo above.
Good luck!
PP - The gars and the dorado are summer fish in Malta. In December the big fish are bonito, amber jack, baracuda and blue fish on spinning and jigging.