These Dagannoths do not hit as hard as the level 92's do, but there are a lot more of them.
Charm Drop Rates
This data is based on the drops from a mixture of level 74, and level 92 Dagannoths.
Dagannoths will hit fairly hard with their ranged and melee attacks. Players under level 90 may find it difficult to train on the these due to the amount of the level 88s in the dungeon. They are excellent training for higher level players with good armour. Guthans is ideal as you can just sit there for ages and have them continuously attacking you. If they stop being aggressive, simply return to the ground floor then come back. Cannons can also be used very well in here - many creatures in close proximity all aggressive to begin with makes for amazing training.
A horror from the ocean depths...
Clue scroll (level-2), Snapdragon seed, Starved ancient effigy
Bones (100%), Coins (23-44), Grimy herbs, Raw lobster, Casket, Tinderbox, Water rune (15), Steel hatchet, noted Seaweed (10), Edible seaweed, 5 Raw Sardine, Steel arrow (15), Mithril javelin (3-6), Cactus seed, Law rune (7-8), Keg of beer, Oyster pearl, Bronze spear, Raw herring (3), Fishing bait (50), Harpoon, Lobster pot, Herb seeds, Belladonna seed, Feather (15-20), Iron spear, Raw tuna, Poison ivy seed, Dagganoth ribs, Gold charm, Crimson charm, Green charm, Blue charm