That is strange. Usually in largemouth ponds pumpkin seeds r an important food source for other fish. Maybe not enough predatory fish to keep them in check I guess.
Just a question, why should you remove bullheads and panfish? To reduce the risk of over population?
Flax Pond is a 48 acre natural kettlehole pond with a maximum depth of 75 feet and an average depth of 36 feet. The 1.1 miles of shoreline are undeveloped, being protected within the confines of Nickerson State Park. Transparency is excellent, aquatic vegetation is scant and the bottom is composed primarily of sand. Nickerson State Park is located just south of Route 6A near the Orleans line. It can be reached via Route 6A, or by taking Route 6, Exit 12, and rejoining Route 6A west. Once in the park, Flax Pond can be reached by taking a left onto Flax Pond Road. Primary fishing access is over the beach area. Cartop boats and canoes can be launched after a short carry down a steep slope. The pond and the surrounding area is heavily used during the summer months by campers, swimmers and canoers. Electric motors only are allowed.
Flax Pond is primarily a trout fishery and is annually stocked, both spring and fall, with brook, brown and rainbow trout. It is deep and cold enough to carry trout through the year and regularly produces some good holdovers, especially browns. These fish often feed in relatively shallow water during the spring and fall and can be taken with flyrod or spinning gear from almost anywhere on the shoreline. During mid-summer, a boat or canoe may be necessary to reach them at depths of 25 to 36 feet. Although trout are the primary focus here, anglers, particularly those fishing with live baits can also expect some smallmouth bass. Tapping or jigging a grass shrimp along the bottom (with a split shot about 18 inches above the hook) is effective on both trout and bass. Anglers should remove any warmwater fish, especially pumpkinseeds and bullheads, that they catch from the pond.