Surprised lamprey aren’t in there.
I’m not exactly sure what you meant by that comment, as I can think of a couple of interpretations, but if it had to do with a need for restoration of sea lamprey in the Schuylkill, you’re correct.
Where naturally occurring, sea lamprey are valuable to the ecosystem in that their young, known as ammocoetes, occur in great numbers in stream, including wild trout stream, and river near shore bottom muds and sand where they survive not as parasites, but as filter feeders, which are beneficial to water quality. The ones that I have seen have been about 4” long. They live and grow in this larval stage for 3-7 years until metamorphosis into about a 6-7” adult-like in appearance lamprey, at which time they migrate to the sea and function as the better known parasitic stage until returning to freshwater to spawn. They no longer feed during that freshwater adult migratory stage and die after spawning, recycling nutrients to the freshwater system.
Research has revealed that restoration requires the presence of young sea lamprey (ammocoetes) in upstream tributary areas. The ammocoetes release pheromones (external hormones) into the water column, which in-migrating adults sense, stimulating the adults to migrate up the tribs. In the Delaware system the Delaware has a substantial population of sea lamprey, but there are no stimuli to migrate into and up the Schuylkill. This is the (pheromonal) pinch point where restoration would need to be focused. As with American eels, which have commercial and ecological values, one of which is to indirectly improve water quality through their upstream transport of freshwater mussel larvae, known as glochidia, the PFBC needs to devote energy to restoration of both species in the approximately 2,000 sq mi Schuylkill basin.
