Wait for Ruckus to trigger his shield then hook him, it will ensure you dont get hit by the slow and that his weapons resets which equals to less damage taken.

Hook him when he does his high damage attack (default Q), it will stop it and not reset his cooldown, he might try to escape but if you hit the next 2 shots you should be golden.

As Barik, drop your Turrets and shield, play a cat and mouse game where youre the mouse, let the turrets do damage meanwhile and keep your shield or cover between you and the turtle.

Pick your hooks well, due to his jump and heals youre best off waiting for your team to help you out with taking him down or when youre sure your hook + next shot will kill him, instead of hooking him just to see him escape again.