On August 8, 1720, Grassy was raided by the French and Mik'maq of the area. As a result, Governor Richard Phillips at Annapolis Royal sent a garrison of Philipps' Regiment of the Foot to protect British interests. A small defense work was built on the spit of Grassy Island and the following year work began on an earthwork on the hill above the spit. The fort, on one occasion referred to as Fort William Augustus, was poorly supported by the government. After only a few years it was lying in ruins.

The soldiers stationed on Grassy Island had very little in the way of luxuries when they first arrived. This situation continuously worsened as time progressed. Between 1735 and 1740 many of the soldiers became ill and some even died. Their barracks often flooded at high tide. They had little food, and their clothing was worn to shreds.

In 1740, with the increasing threat from the French and the Mik'maq, the officials at Annapolis began to seriously consider fortifying the island. Bastide, a royal engineer, came to Canso and drew up a map for a "new" fortress that would supply housing for 100 men and serve well as protection for the area and its' fishermen. Unfortunately it was never implemented. War between England and France was declared on May 3, 1744. The Canso fishing station was attacked soon after. The fears by local inhabitants were finally being realized.

DeQuesnel, Governor of Lousibourg, sent 350 men headed by Captain Joseph Dupont Duvivier to attack Canso. Although inexperienced in battle, Duvivier had a substantial knowledge of the New England position at Canso. On May 23, 1744, a flotilla consisting of two privateers, fourteen fishing vessels, and a supply sloop carrying 350 officers, sailed out of Lousibourg en route for Canso. Due to the deplorable conditions at Canso, Duvivier could have sent half that amount of forces and still claimed a swift victory. The force that existed at Canso consisted only of approximately 87 soldiers, a third of which were either sick or lame.

Less than six hours after Duvivier's arrival at Canso, acting commander of the garrison Captain Patrick Heron surrendered. Heron hoped that with the quick surrender they would be able to gain better bartering terms. Duvivier allowed all the inhabitants of Grassy Island to return to Boston. The military were to be held captive at Louisbourg for one year. This one year term was later reduced when Louisbourg's own resources began to be depleted. A new deal was struck between Heron and Duvivier in which it was agreed that the soldiers would be allowed to return to Boston in exchange for French prisoners. They also agreed to not attack Louisbourg before September of the following year (1745) (this part of the agreement was slightly broken).

With the arrival of Duvivier, the community of Grassy Island had been burnt to the ground. One of the main reasons why they chose to attack Grassy, besides the message it would send to Annapolis, was to open up the trading routes that were currently hindered by the existence of the Canso station. Louisbourg was practically starving at this point due to being cut off from its' main supply sources. Once Grassy was defeated, more than 100 head of cow and thousands of sheep were transported to Louisbourg from Acadian settlements throughout Nova Scotia. Even after the attack though, Annapolis continued to neglect its' outposts for many months to come.

This eventually changed though. Grassy (Canso) Island saw the arrival of Pepperell's forces on March 27, 1745. The soldiers trained on the island and began construction of a new fort in early April. Vaughan and Shirley, officials in Boston, had authorized an attack on Louisbourg. Most of the troops on the island were to train for the attack on Louisbourg. Two companies, however, were to stay on the Island and start construction of the new fortress. Captain Jeremiah Cutter, the commander of the companies for construction, arrived at Grassy on April 13, 1745. As with the past attempts at construction on the Island though, Annapolis seemed to neglect its own orders, and never sent enough supplies and food to build the fort and keep the soldiers going. Cutter was very vocal on this issue, to the point where he was removed from office. A man named Eveleth replaced Cutters' position at Grassy. Soon after Eveleth found the situation dreadful as well. Annapolis eventually gave up on establishing fortifications on Canso (Grassy) Island. Since the troops that had been training on Grassy, were victorious in their attack on Louisbourg, fortifications at Canso were no longer needed. The troops were eventually removed from the island.

What type of products did the Canso Islands produce in the mid 1700's?

(Canadian Parks Service, Atlantic Regional Office, Research Bulletin, No. 253, February 1987)

The fishery was very much alive in the mid 1700's. The price of fish fluctuated substantially over the quarter-century of the New England Fishery. In the late 1720's it would drop as low as seven shillings sterling per quintal (quintal equalled approximately 100 pounds). By 1732 it had risen to 12/6 sterling. On average it remained between eight and ten shillings per quintal. Fishermen were usually paid in shares based on the vessel's catch. Most of the time one half of the proceeds went to fishermen while the other half went to the owners of the vessels. The owner often paid for provisions and equipment.

The Canso fishery's main product was salted fish, and dried salted cod. The high quality cod was sent to the Mediterranean where there was a large demand for it. Poorer quality cod which was damaged during curing, known as "refuse" fish, was sent to the Carribbean as food for slaves that worked on the plantations.

A minor by-product of the fishery was cod liver oil, used chiefly in the tanning industry. Only a few barrels were made yearly at Canso, ranging from a low of 28 in 1729 to 486 in 1737. Most of this product was shipped south to New England at the end of the fishing season.