You find them on Saturday. Good fish, a repeatable setup, the tide doing the thing you hoped it would. You go back Tuesday.
Is it the same fish?
The honest answer is partly, and it depends enormously on what kind of place you found them in. Acoustic tagging has been quietly answering this for a decade and the numbers are more useful than the question sounds.
Two very different kinds of water
Put the studies side by side and the pattern jumps out.
| Study | Where | Residency |
|---|---|---|
| Hollema et al. 2017 | Plymouth–Kingston–Duxbury Bay, MA | 6–75 days in the bay |
| Kneebone et al. 2014 | Stellwagen → Massachusetts state waters | 119 of 125 fish detected for 1–56 days |
| Rothermel et al. 2020 | Maryland shelf | mean residency ~2 days |
Same species. An order of magnitude apart.
The difference is not the fish, it is the function of the water. A productive Massachusetts embayment is a feeding ground — Hollema's tagged fish overwhelmingly took up residency for the summer months. The Maryland shelf array sits on a migration corridor, and a corridor is somewhere you pass through. Fish there were transient, with stays over two days appearing mostly in autumn and winter.
So "how long do stripers stay?" has no single answer. It has two, and knowing which one applies to your spot is most of the value.
What that means for the place you fish
If you fish a bay, an estuary, a back harbor — somewhere with forage and structure that fish settle into — you are probably fishing a population that holds for weeks. Tuesday's fish has a real chance of being Saturday's fish. Learning that specific piece of water pays off, because the animals are still there to be learned about.
If you fish a corridor — an open beach on the migration route, a point that fish round rather than live on — you are fishing a conveyor. Tuesday's fish is almost certainly not Saturday's fish. But that is not bad news. It means the spot is being continuously restocked, and the question stops being "are they still here" and becomes "is the flow still running".
Massachusetts summer venues turn over either way. In Plum Island Estuary on the North Shore, fish tagged in spring and early summer stayed about two months on average — 66 and 72 days in two seasons (Pautzke et al. 2010), 69 days in a later study (Mather et al. 2025) — and nearly all had left by November. The estuary is full all summer. It is not full of the same individuals all summer.
Reading the ranges
The tagging papers publish the range of stays — 6 to 75 days in the bay, 1 to 56 days in state waters — more than a typical stay. Hollema's fish were in the bay for at least 30 days on average, give or take 19 (the paper's "minimum residence time"). Read the ranges as the envelope: some fish stay days, some most of a season.
What to do with it
Work out which kind of water you have. Not from the map — from your own log. If your good sessions come in runs that last weeks, you are probably on residents; if they arrive as isolated hits, you are probably on traffic.
On a corridor, fish the arrival, not the memory. What made yesterday good was fish moving through. Today's question is whether more are moving.
On a feeding ground, invest in the detail. The same animals are there for weeks, which means the specific bar, the specific stage of tide, the specific lane is worth learning properly. That knowledge has time to pay.
And do not read a blank as departure. A fish resident in a bay for forty days is not catchable for forty days. Residency and catchability are different things, and one blank tells you almost nothing about the first.
How StripedLines uses this
StripedLines is built for striped bass. Because the fish at any spot keep turning over, StripedLines rates the water they move through, not the fish. No rating in the app says a spot is holding fish right now; it ranks the water in front of you against your other options.