Yes. Until you defeat the Captain, the governor will not give you the directions to the treasure buried on Skullduggery.
Nothing. Captain Crawfish was there. But you don't exactly do anything on Skullduggery island. You defeat Crawfih on sea.
well after you defeat Captain crawfish you enter skullduggery island. after finding nothing you head back to the main island and talk to the guy in the governor's house, he will give you a treasure map and shovel from there you go bak to skulduggery and meet captain crawfish to whom you defeat.
There is nothing to be found on the hidden island (Skullduggery) until after you beat Captain Crawfish. After you defeat Captain Crawfish, the governor gives you a treasure location and a bone shovel. Sail to the hidden island. You will find the treasure under a mound, six paces right from the pirate flag.
Once you defeat Captain Crawfish, and collect all five map pieces, you can go to the new island (Skullduggery) and dig up the buried treasure. Before you have done these two tasks, the island has no purpose. After Captain Crawfish has been chased away, the Governor will give you the treasure location and bone shovel. (In order to beat Captain Crawfish, you will need the strongest ship, the Phoenix Warbird.)
After you defeat Captain Crawfish. Assemble the map from the five pieces to reveal the hidden island (Skullduggery). Then continue trading until you have the largest ship, the Shipwright, and the Cannoneer. That will let you defeat Captain Crawfish. Once you have beaten him, go back to see the governor at Fort Ridley to get the directions to the buried treasure.
Once you defeat Captain Crawfish, and collect all five map pieces, you can go to the new island (Skullduggery) and dig up the buried treasure. Before you have done these two tasks, the island has no purpose. After Captain Crawfish has been chased away, the Governor will give you the treasure location and bone shovel. (In order to beat Captain Crawfish, you will need the strongest ship, the Phoenix Warbird.)
You will need to amass your doubloons to buy larger ships, because only the largest, the Phoenix Warbird, stands a chance against Captain Crawfish. (see related question)
Once you have all five, merge them together to reveal a 6th island (Skullduggery) at the bottom center of the map, near the Pirate Outpost. You cannot do anything there until you get the largest ship and can defeat Captain Crawfish. Once you defeat Captain Crawfish in battle, take the map to the Governor and he will give you the Buried Treasure location and the Bone Shovel. Now you can dig up the treasure on Skullduggery.
To get the bone shovel, you have to defeat Captain Crawfish. Return to Fort Ridley and the governor gives you the treasure directions, and a bone shovel to dig with. Go to the small island, Skullduggery, and follow the directions to the treasure.
There is nothing to do there until you defeat Captain Crawfish. Get larger ships as soon as you can to raise 500,000 doubloons toward the 1,000,000 you need to get the Phoenix Warbird. (You can borrow another 500,000 at the Golden Harbor Bank, but don't get sunk with them aboard!) After you defeat Captain Crawfish, go back to Fort Ridley and the governor will give you a shovel and a map to the treasure on Skullduggery. You can go there and dig it up.
When you have the 5 map pieces, another small island appears on the map near the Pirate Outpost. But you can do nothing there until you defeat Captain Crawfish. Keep collecting doubloons and salvage, and buying new ships and crew, until you have the biggest ship, the Phoenix Warbird, and the Shipwright and Cannoneer. With these, you can defeat Captain Crawfish and the governor will give you the map to the buried treasure on Skullduggery.
Once you have the Phoenix Warbird, with the Shipwright and Cannoneer aboard, you can battle Captain Crawfish. Once you defeat him, you get the location of the treasure on the new small island. Go there to dig it up. You will not see Captain Crawfish's ship once you get the treasure location and the shovel from the governor. He will show up when you are digging.