"Many are restricted in their distribution ranges and live in separate populations or fish stocks based on geography."

Stocks, as in stock market

"The term "mackerel" is derived from Old French and may have originally meant either "marked, spotted" or "pimp, procurer"."

Procurer = trader?

"Flocks of seabirds, whales, dolphins, sharks, and schools of larger fish such as tuna and marlin follow mackerel schools and attack them in sophisticated and cooperative ways.

Mackerel schools = stock traders?

Whales spew water = information Dolphins make clicks = keyboard Sharks smell "blood in the water"

https://en.wikipedia.org/wiki/Mackerel