To catch fish in a fall blitz, knowing how to identify baitfish before you cast is essential. It can be done a few ways: net a sample from the wash, watch how the baitball behaves, and read the birds for size class. Striped bass, false albacore, and bonito feed selectively inside a blitz, keying on one forage type and size at a time, so matching the bait in the water beats reaching for last week’s fly. The five species you’ll see most from Cape Cod to Cape Hatteras are bay anchovy, Atlantic silverside, sand eel, peanut bunker, and mullet.
Bay Anchovy vs. Silverside: The Distinction That Matters
Popular sources often treat bay anchovies and silversides as the same fish. They aren’t, and the difference changes your fly.
A bay anchovy (Anchoa mitchilli) has a single dorsal fin and a large mouth extending back to or past the eye. It’s translucent with a silver stripe and usually runs one to three inches in fall, the classic “rain bait” or “glass minnow.”
An Atlantic silverside (Menidia menidia), or spearing, has two dorsal fins and a small, upturned mouth, a firmer, more opaque body, and commonly runs three to four inches. The quick in-hand test: two dorsal fins and a small mouth means silverside; one dorsal fin and a huge mouth means anchovy. Both want a slim, translucent fly, so the practical difference is size, which is what the fish are selecting on.
The Other Fall Baits, and How to Tell Them Apart
Sand eel (American sand lance) is pencil-thin with a pointed snout and no pelvic fins, most commonly four to six inches but ranging from one to ten. It burrows in sand, scurries on the surface in low light, and holds on the same sandbars for weeks. Size to your local sample rather than a fixed number.
Peanut bunker (juvenile menhaden) is deep-bodied and compressed, silvery with a dark back and a black shoulder spot, running two to five inches (up to eight-inch “lollipops”). It won’t take a hook, so net it to sample.
Finger and corncob mullet are the same species at different sizes, three to six inches and eight to ten. They swim just under the surface and leap when pushed, leaving V-wakes in skinny water.
Also expect young-of-year herring (one to three inches) near river mouths on dropping tides, and larger butterfish and mackerel from mid-September on.
Read the Bait Without a Net
You won’t always net a sample, so read behavior. Anchovies “rain” at the surface in tight clouds. Mullet leave V-wakes and jump. Peanut bunker circle tightly and flip their tails audibly. For the birds, read size class: terns signal small bait (anchovy, silverside, sand eel, peanut) and often smaller fish; gannets and large gulls signal bigger bait and potentially bigger fish, though gannets sometimes work bait with no gamefish beneath. Baitball shape helps too, the tighter the ball, the smaller the bait, and long, stationary feeds usually mean small bait while short, fast eruptions suggest something larger.
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Slim, translucent bait (sand eel, silverside, small anchovy) calls for a sparse Surf Candy, a sparse Clouser, or a Cowen’s Albie Anchovy in sizes 4 to 6, white, chartreuse, or tan. Deep-bodied bait (peanut bunker, herring) calls for a water-pushing profile like a Lefty’s Deceiver, a Hollow Fleye, or an EP Peanut Bunker. Surface-oriented mullet is the time for a Gurgler, Crease fly, or popper. When fish are in reaction mode rather than picking selectively, matching the bait exactly or going the opposite direction with a bigger, louder fly both work, so read the fish’s mood alongside the bait.
Find the fish by the birds, then identify the bait by net, eye, or bird size class before you commit to a fly. That order, location first, then identification, then pattern, is what turns a blitz you found into a blitz you caught.
FAQ
What is the difference between a bay anchovy and a silverside?
A bay anchovy has one dorsal fin and a large mouth that extends back to or past the eye, while an Atlantic silverside has two dorsal fins and a small, upturned mouth. Anchovies are translucent and usually one to three inches; silversides are firmer, more opaque, and commonly three to four inches. Both call for slim, translucent flies, so the practical difference is matching the size.
How do you identify baitfish during a striped bass blitz?
Net a sample from the wash or surface with a cast net or dip net, examine any bait a hooked fish regurgitates, or read behavior and birds when you can’t net. Anchovies shower at the surface, mullet leave V-wakes and leap, and peanut bunker circle tightly. Terns indicate small bait; gannets indicate larger bait.
What fly should I use during a fall run blitz?
Match the bait’s profile first. Use a sparse Surf Candy or Clouser (sizes 4–6) for slim bait like sand eels, silversides, and anchovies; a Deceiver, Hollow Fleye, or EP Peanut Bunker for deep-bodied peanut bunker; and a Gurgler or Crease fly for surface-feeding mullet. When fish are aggressive, a larger or louder fly can outproduce an exact match.
Why won’t the fish eat my fly during a blitz?
The most common reason is a fly that’s too big or the wrong profile for the bait the fish are keyed on. Gamefish in a blitz are usually size-selective, and the target bait can change with the tide, so re-check what’s in the water if a fly that worked earlier stops producing.
What size fly matches a sand eel?
Match the local sample, since sand eels range from one to ten inches but most fall fish are four to six inches, roughly the diameter of a Sharpie. Tie or choose a slim profile such as a long Surf Candy or a sparse Clouser in that length rather than relying on a single fixed size.
