I'm pretty sure it is; it just happened again.

Looks like i can expect twice-yearly runs.


The mass of Shad appears at the downstream portion of the river, flows fairly quickly upstream and then swims off the map. It moves as one cohesive mass and the whole process takes maybe 2 minutes.

This is vastly different from the usual Vermin locomotion (that is to say, teleportation), these Shad do not teleport, they actually swim from square to square, so i can only conclude this was deliberately programmed into the game; if it was an accident i'd expect to see them teleporting around like crazy, and i wouldn't expect to see it in repeated by short intervals.


No, i think DF has salmon runs programmed into it.

I love these little details that Toady codes in, possibly wondering if someone will ever stumble upon them. Neruz, do you mind taking a video of it next time? Seems like it'd be pretty cool to watch.

In my mermaid-farm ocean-side fortress, I have seen schools of anchovies migrating along the shoreline.  While vermin teleport, they don't do so in a random way;  depending on type they stay in groups and travel in a definite pattern.  I don't know what tags define it, but it's cool to watch.

I saw something like this once. Not a full blown salmon run like you have, but definetly a migration.

In that fort, I had a brook which froze during the winter and I noticed that shortly before the brook froze over, there would be a migration of a group of salmon upriver I think. It happened like clockwork since it would come through not long before the river froze and I used it as a cue that the brook would freeze over.

Heh, in my first long-running fort I had a batsplosion. I was concerned they'd attack my fort so I mobilized my crossbowdwarves. >.<

I had a batsplosion too in one fort which apparently had a chasm home to many millions of bats. At one point, they filled one of my main hallways, so much that I wondered if they were causing problems by clogging the hallway. Dwarves who hated bats had a horrible time in that fort.

 I've noticed that effect before in the ocean with jellyfish.  It's quite surreal to see what looks like a swarm of statues suddenly washing up on shore.  The pattern in the ocean is a lot more circular at first and flows with the waves towards the shore.

Now that people will be doing more non-mountain sites, I bet we will be observing more stuff like this.

I've never seen a full blown salmon run in DF, mainly because I embark in mountains where there are only brooks.

Also, what is the mussel doing in there? I've never seen them spawn in brooks or streams, although I've had fisherdwarves 'fish' freshwater mussels out of brooks before.