There are several Ancient Rock Slabs that can be found in the land of Dredge. In these rock slabs are different carvings depicting fishes and other sea creatures, suggesting that offering the right creatures will result in something that might help in fishing.
Below are all of the Ancient Rock Slabs and solutions on how to complete them in Dredge:
The Marrows Ancient Rock Slab Shrine
The Ancient Rock Slab Shrine at The Marrows (J9) show crude symbols of curved fish. To complete this shrine, you will need to catch 5 Cods in The Marrows and then bring all the fishes to the shrine. Then, place all Cods in the grid arranged so that all of them fit perfectly.
After completing the rock slab, you will then be rewarded with the Sinew Spindle, a 2-slot rod part that adds 6% fishing speed and can catch coastal and shallow fishes.
Gale Cliffs Ancient Rock Slab Shrine
The Ancient Rock Slab Shrine at Gale Cliffs (P3) show three crab-like carvings. To complete this shrine, you will need to catch 1 Decorator Crab and 2 Rock Crabs in Gale Cliffs and then bring all the crabs to the shrine. Then, place all crabs in the grid arranged so that all of them fit perfectly.
After completing the rock slab, you will then be rewarded with the Mouth of the Deep, a 6×6 cage that has a yield of 3 per day.
Stellar Basin Ancient Rock Slab Shrine
The Ancient Rock Slab Shrine at Stellar Basin (H2) show four large, powerful fish carvings. To complete this shrine, you will need to catch 1 Hammerhead Shark (oceanic) in Stellar Basin during daytime, 1 Bronze Whaler (oceanic, daytime) and 1 Blacktip Reef Shark (oceanic, nighttime) in The Marrows J8-K8, and 1 Ghost Shark (abyssal) in Devil’s Spine Q13 during daytime. You can bring the sharks to the altar one at a time if they cannot fit in your boat all at once.
After completing the rock slab, you will then be rewarded with the Viscera Crane, a crane that adds 55% fishing speed and can catch abyssal and hadal fishes.
Twisted Strand Ancient Rock Slab Shrine
The Ancient Rock Slab Shrine at Twisted Strand (D13) show a twisted shape of a deformed fish. To complete this shrine, catch an aberrated type of any fish and place it in the grid.
After completing the rock slab, you will then be rewarded with the Tendon Rod, a fishing rod that adds 28% fishing speed and can catch oceanic, mangrove, and shallow fishes.
Check out this video by Game Guides Channel showing how to complete the Ancient Rock Slab puzzles in Dredge: