Deconstructing mortality.

New research out of Alberta puts numbers on something I addressed in a previous post- big, rare, charismatic predators like bull trout generate lots of likes and clicks- and that may have consequences for trophy fisheries. Even with C&R.

The study compared two groups of fish:

  • A control group, where adult bull trout were immediately released.
  • An experimental group, which received the full Instagram treatment- hoisted, photo’d, fumbled (the paper’s author makes a point of mentioning big fish are tough to handle for anyone, especially inexperienced anglers). Fish in the experimental group were out of the water as long as 112 seconds.

Fifteen percent of big fish (3 out of 20) died in the control group, even with everything done by the book. But fully a third (10/30) fish from the Instagram group died, far above the <5% mortality most C&R anglers assume (and even that’s charitable, as I’ve met many C&R anglers who’ll swear up and down they’ve never released a fish that subsequently dies).

We’re talking about small sample sizes, 20 and 30 fish. But for a low-density apex predator like bull trout it may represent a season’s total spawning effort. For imperiled fisheries in the Pacific Northwest, that may represent the entire run of a stream’s wild steelhead or salmon.

The study’s worth thinking about. Fisheries managers often assume mortality is a constant across angling demographics, and model population structure and fishing regulations under the same premise. If these results can be replicated for other fish stocks, it may demonstrate a relatively small proportion of C&R anglers have an outsize impact on the quality of trophy, C&R fisheries.

The study has implications for how anglers behave in the age of social media, too. From fish porn and the grip ‘n grin, to hotspotting and the zero2hero subculture that pervades certain corners of the Fly Fishing Industry.

If your paycheck or your pro-deal hinges on magazine quality photos of slob fish, perhaps from time to time the welfare of that specimen is going to take a back seat. If some subset of anglers has an outsize impact on fish populations, broadcasting their next destination may be unwise. If some subset of anglers Does it For the Gram, if Influencers encourage novice anglers to target trophy fish for Likes and Clicks, perhaps it isn’t out of concern for the species or the sport.


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