Fog

Fog is a Known Occurrence in Salmon Run.

Description
Fog will cover the battlefield during this event, making it more difficult for players to see. Additionally, Salmonids spawn all over the map instead of concentrating on a single area at a time. Although it is said to be rare, at least two Goldies will spawn during Fog, so keep an eye out for them.

Fog can occur at any tide level.

Salmonid Field Guide
The following text is quoted from the Salmonid Field Guide.
 * What Happens
 * The area is covered in a dense fog, drastically reducing visibility.
 * Enemies will take advantage of the fog and attack from all directions.
 * How to Get Golden Eggs
 * Defeat Boss Salmonids.
 * The extremely rare Goldies may appear in foggy conditions.
 * Advice from Mr. Grizz
 * Try to maintain contact with your teammates at all times while in the fog.
 * Being alone in the fog is extremely dangerous.
 * Supplementary Information
 * Goldies are extremely rare Salmonids&mdash;only one of every 10,000 hatchlings is a Goldie.
 * They live longer than and possess far superior intelligence to normal Salmonid specimens.

Tips

 * Lure Goldie and mobile Boss Salmonids as close to the Egg basket as possible. If the team is lucky enough to drop a bit ammount of Eggs from the Goldie, it's possible to meet the quota early, which will allow players to prioritize surviving.
 * Be aware of the surroundings when collecting Eggs near the basket. If all the crew gathers too close to each other and focuses solely on the Eggs, Salmonids can overflow the stage and easily whipeout the team. Long range Boss Salmonids are especially dangerous in such situation.
 * Because it's much harder to navigate through the fog, try to take out Flyfish, Stingers and Big Shots if it's save. Don't ignore Fish Sticks, or it'll be very hard for the crew to control the turf.

Trivia

 * Fog and The Mothership are the only Known Occurrences that can occur no matter the tide.