Loligo opalescens is said to have about a 1.5 to 3 year life span; longer in the cooler northern waters, but I don’t know for sure if that is correct. In the early 1980s the squid spawned each spring in the Barkley Sound region. It was regular enough that I planned on it for my Invert classes. However, by the late 1980s the squid had disappeared. I don’t know if they even come into the area now. The last times I was teaching up there, in 1996-1998, 2002, there were no squid seen at all. My guess is that the climate change and perhaps offshore trawling/overfishing altered what had been a regular pattern.

I had heard about the Humboldts as you described. My guess, as well, was that they had had a spawning event. But, hey, nobody asked me.
As far as I know, nobody has documented their spawning, so there is no guess as to where it would be or what depth. If they did spawn, then sometime latter small squidlets might start showing up in somebody’s sampling … or not. I suspect it would take some luck to get a few babies in a plankton tow, but stranger things have happened.

Sorry it was necessary but thanks for re-posting this – the scale of the event is mind boggling!

Two Questions:

1. Was there any ‘local lore’ or other information to indicate how often such an event might occur? I’ve been told that most squid species live about one year implying that these spawning aggregations ought to be an annual event. OTOH: Squid jigger lore around here would indicate that such events are quite spotty and several years could separate large spawnings.

2. Last fall we had a large influx of Humboldt squid. The first indication came from salmon fisherman reporting hooking a fish and then landing half a fish plus a great big squid. Within a few weeks dead Humboldts started washing ashore in big numbers. To me this seems consistant with a mass spawning but the biologists I’ve asked reply with a shoulder shrug. I would appreciate your thoughts.