The whole-roaste shark head

[LeTzar]

I can not kill the shark and I think I am far behond this level with the sushi bar (next up, the tuna party)... impossible to keep up with no "staff". How do I do it ?

[Onyx]

The roasted shark head mission unlocks staff recruitment. Are you using your rifle? Unload all your ammo into the shark, then swim around to pick up extra ammo to come back and keep shooting it.

[GrandTickler]

maybe scout around for a sniper rifle first, since its the easiest weapon to take out sharks with, without even being charged once. if you are having trouble reading its body language and setting it up to counter attack it, a underwater scooter making small taps to evade its attacks, or movement speed related accessories if u have unlocked any can help too.

i find the easiest way to take it out with a plain harpoon attack is to bait his charge attack at a diagonal angle and then go slightly bellow it and slow time while aiming, to shoot him in its belly

[Axe]

You may be simply too early in the evolution of the initial game.

How many hours have you played. It may just give a vague indication of your progress so far?

[Miles Mayhem]

This shark is an overall difficult encounter as it is early in the game. But you can play on time here - invest in gear and when trying to taking on him, do it as first thing when diving in... so you do not lose much time/stuff if things go sideways

[Bobucles]

The default harpoon isn't going to cut it, and melee is way too risky on a shark. Use the starter gun, or upgrade the harpoon to hit harder. Above or below enemies tend to be very difficult to fight, so try fighting on a horizontal area.
Beware that when the shark finishes lunging it will turn around, which will move it about half a body length towards you. Keep a safe distance and wait for the turn before shooting.

[Nakos]

Yeah, use the rifle on the Shark. Learn its pattern, it'll lunge and you want to dodge when it does. Shoot, dodge, shoot, dodge. etc. And yeah, look for more ammo, (And more O2).

[Axe]

Later down the line the Harpoon will kill the sharks no messing so long as you (still) use the tactics as mentioned above.

[Captain Cosmo]

Whitetip Reef Sharks are the weakest sharks in the game, approximately 45-50hp. Upgrade your harpoon twice and they take about three hits. Tuna are tougher by far, so harpoon upgrades are mandatory to progress in a timely manner. Second, bullfight the shark. Wait for it to charge (which it telegraphs with tail swishes and I think scrunching up), swim up or down right before the charge, and hit it when it stops. Preferably you'll be near (but not against) a wall so it runs into it giving you a chance to hit twice. They're a cakewalk as you get further in the game but you need Kyoko and for her you have to get the shark head to hire staff.
Others are suggesting the rifle and yes, that is a valid strategy. The rifle has longer range so if you're not comfortable with getting close enough to harpoon it that's the way you should go.

[CWEastwood]

Just started playing. Takes 9 shots with the basic rifle. Best to fight it unencumbered. Allow it to target you. Swim perpendicular to its attack vector and fire once it's cleared you. You can get another shot off while it's relocating you. Swim away to create distance and repeat. After your 8 shots you can strike it a few times with your harpoon or find an ammo box to refill.

[Axe]

Get a bigger weapon LOL

You are still equipped only for those little Blue Tangs ;-)

No need to run before you can walk. They are forever there.