Those unsightly black spots on the skin (and sometimes in the meat) of a fish are probably tiny parasites called neascus, or black grub. The black spot is actually a protective case formed around the grub by the fish's body. Don't worry-neascus is not harmful to humans and if you don't tell your dinner guests, they might think the flecks are just pepper. What freshwater fish found in North America makes the longest spawning migration? The winner, hands down, is the American eel. The females spend most of their lives in big rivers like the Mississippi. When spawning time approaches, they swim downstream to join the males at the river mouth, then they swim to the Sargasso Sea (a portion of the North Atlantic) to spawn. Channel cats love catalpa worms, which can be found on the leaves of catalpa trees from late spring through summer. To make a catalpa worm even more irresistible, cut off the head and then poke a matchstick through the body to turn the worm inside out. The extra scent helps cats find the bait more quickly Some veteran bream anglers can find schools of spawning sunfish by sniffing for them. When bream such as bluegills and shellcrackers gather to spawn, milt sprayed over the females' eggs emits a strong, fishy odor. To the fisherman with a good nose, the smell is a dead giveaway. Follow the scent trail upwind until it is undetectable, then start fishing a bit downwind from there. Ever wonder if a fish that you can see can see you, too? It can, provided you're in its window, which is a round area on the surface directly above the fish. The diameter of the window is about twice the fish's depth. What's the longest anyone has fought a fish in fresh water? The record appears to be held by an angler on the Kenai River, Alaska, who reportedly fought a 100-pound-plus king salmon for more than 24 hours. He finally lost it at the net.