The site Information Dissemination has a post Swarm Tactics with some photos from a Sina article: 50 pirate vessels driven out by Chinese naval fleet
I don't agree with the original captions from Sina or the comments at I.D. I have put the original captions at the top of each photo and my own captions at the bottom in bold.
About 50 suspected pirate vessels approach a ship escorted by the Chinese naval fleet in the Gulf of Aden, Feb. 25, 2010. The vessels harassed the 31 Chinese and foreign ships that the naval fleet was escorting. They were driven out soon after the fleet dispatched vessels and helicopters. (Xinhua Photo)
I began routinely making transits through the GoA in 1999, before pirates became a problem, it wasn't uncommon to see fisherman acting the way they are shown in the photo above.
Next photo from the same post.
A suspected pirate vessel is driven out by the Chinese naval fleet in the Gulf of Aden, February 25, 2010. (Xinhua Photo)
Regarding the use of large outboard engines on fishing skiffs, it is sometimes asserted that fisherman have no need for such powerful engines on their skiff but in fact it is a long standing practice, in place prior to the piracy problem in the area:
From: A REVIEW OF THE BIOLOGY AND FISHERIES FOR LONGTAIL TUNA (THUNNUS TONGGOL) IN THE INDO-PACIFIC REGION
Two types of vessels are engaged in fisheries for longtail tuna. One type is the traditional design dhow constructed of wood ranging in length from 10 to 25 m. These vessels are powered by inboard diesel engines of 33–240 HP. The other type is the planing hull skiff constructed of glass-reinforced plastic (GRP) ranging in length from 5 to 9 m. These skiffs are powered by outboard engines of 25 to 120 HP.
Another characteristic of the fishing vessels which seems suspicious is the often apparent erratic behavior of the fishing skiff, but again I have observed the same behavior prior to 2007 when the piracy problem first began. Here from:
Information and Guidance to Shipping in Gulf of Aden and adjacent waters.
Most small boats in the area are legal fishing boats. This is in particular the case south of Aden and southeast of Mukalla. Those fishing skiffs are using aggressive manoeuvres and weapons might be seen, as these fishermen occasionally also are victims to armed robberySuppressing piracy in the Gulf of Aden is problematic because it is difficult to distinguish between fishing skiffs and pirate skiffs.
From Information Dissemination again an explanation: Somalia Piracy - A Backgrounder
There are typically around 6000 small fishing skiffs off the coast of Somalia and in the region, with an additional many hundred larger fishing vessels (similar to dhows) in the region. It is very difficult to tell the difference between a fishing vessel and a pirate vessel, all of the vessels look the same.The reason that suppressing piracy in the GoA is so difficult is that the pirates use the same type of outboard powered skiffs as the fisherman.
Below, (from Modern Day Pirate Tales) is a pirate skiff, note the hooked ladder used for boarding ships.
(photo: MCorporal David Tillotson, Air Detachment HMCS Winnipeg, CF Combat Camera)
The tip-off is the ladder, fisherman don't use ladders.
I've seen comments and been asked why not just shoot the pirates but it is not a question of firepower or will but one of identification. First step to solving a problem is understanding it.