Yes, the amount of fish necessary for 1 fish oil supplement is indeed this high.
1 Testa capsule contains 450 mg Omega-3, thus 60 capsules contain 27g of Omega-3.
1 herring on the Dutch market weighs on average 68 g and contains on average 1.1% extractable Omega-3. Thus 750 mg Omega-3 per herring.
If we then divide the 27g of Omega-3 of 1 Testa supplement by 750 mg of 1 herring one can see that 36 herrings are used.