Herring Scrap 29 - Charting The Harvest Level Proposals

This scrap is dedicated to the volunteer members and meeting-goers of Sitka's Local Advisory Committee to the Board of Fisheries. They've been meeting every week for a few weeks now (mostly about salmon so far) and will be meeting every week for a few weeks more (including about herring), considering and advising on Sitka-related Proposals that the Board of Fisheries will be looking at in January. There's a lot on their plate this Board cycle.

Today I want to collectively highlight the herring proposals which are related to thresholds and biomass. I hope to accomplish two things in this scrap - First, I want to offer a chart that helps conceptualize how the different harvest formulas for these would play out at different levels of biomass, as a way to help meeting-goers and AC members conceptualize how they differ or are compatible together. Then, I want to really emphasize the importance of 1) a higher threshold, given the deficiencies with the Unfished Biomass study; and 2) a hard cap, as a precaution against expanding use of herring for high-volume products like fish meal and oil as signaled by the Herring Revitalization Committee.

But first, allow me to recap the last few scraps, as I think they're relevant to consideration of these harvest-rate related proposals:

In scrap 26, I introduced a "simulation study" that ADF&G recently authored on "Unfished Biomass". I explained one critical way that the data informing the simulation is corrupt - the foundation of their model is data that is supposed to exist, but under closer scrutiny does not appear to exist. I'll circle back to this and can continue to provide more evidence, but what I'm driving at is that it is preposterous for ADF&G to make claims about biomass in the way that they are doing.

In scrap 27, I pointed out the way that Unfished Biomass is linked to ADF&G-authored Proposal 171 from this year's Southeast Alaska Board of Fisheries meeting - that, in fact, the whole purpose of doing the Unfinished Biomass Simulation Study was to have a Proposal 171 - to update an old decision made with old science with a new decision based on new science. I tried to emphasize that if the Unfished Biomass figure is low due to over-interpreted junk data, then the Board of Fisheries will take that information and create a low threshold level, and herring will thus be under-protected at low abundance.

In scrap 28, I identified that the CFEC and Board of Fisheries appear to be moving towards collapsing herring permit structures in a way that could allow year-round herring fisheries of uncertain scale for uncertain purpose on the basis of super-high biomass assessments that ADF&G has been coming out with.

Fishing Threshold and Rate Proposals

Here's a visual to represent the five different proposals which are related to the threshold level and the harvest rate formula - proposal 171 by ADF&G, proposal 174 by Herring Protectors, Proposal 175 by Andrew Thoms, and Proposals 176 and 177 by Sitka Tribe of Alaska. Those formulas each hinge on some combination of three key numeric ideas: what the low threshold should be (below which fishing can't occur) and what percentage of the biomass can be taken at different levels of perceived abundance (and how that is calculated), and whether a hard cap should exist and what it should be.

In the chart below, each colored line represents the relationship between forecast biomass and the Guideline Harvest Level for one of the 5 GHL-related proposals specific to Sitka Sound. The legend offers a cheat-sheet for how each formula uses threshold, harvest percentage, or a hard cap. For reference, I've included grey dashed lines to represent Average Guideline Harvest Level (13,068 tons) and Average Catch between 1979 and 1996 (5,638 tons) and Average Catch between 1997-2024 (11,735 tons) to capture how much the capacity and entitlements for this fishery have grown - and could yet grow - since earlier days.

I hope this chart helps illustrate the effect of each of the threshold-and-rate proposals under consideration. They're very different, resulting in a big range of harvest outcomes at different biomass levels. But - and I think this chart helps illustrate this - the proposals are kind of co-compatible and can be combined to be stronger.

I want to note a few things:

1. I've scaled the chart to capture the point where Sitka Tribe of Alaska's Proposal 177 reaches a 20% harvest rate, at 300,000 tons. Notably though, the 2024 GHL (81,246 tons; compare to vertical axis) and biomass (406,228 tons, compare to horizontal axis) are off-the-chart high.
2. The largest single-year harvest of herring in Sitka Sound was in 2022 - at 25,090 tons. It took weeks of fishing effort and disruption of spawning grounds to reach that level. Processors can only handle ~2,000 tons per day in Southeast Alaska. That limitation means that a quota like this year's quota 81,246 tons is impossibly out of reach for a sac roe fishery, given how fleeting the herring spawning event is. However, if the CFEC and Board of Fish collaborate to change the product-based permit structure and, accordingly, the regulations, to something that accommodates fish-meal&oil production, then a harvest at that level in the Sitka area becomes plausible. A hard cap is a simple mechanism to guard against that future.
3. The model has been conditioned on junk data, and the result is that the agency promotes a distorted vision about historic abundance. The Unfished Biomass and resulting threshold are too low as a direct consequence of the junk data. I urge the local AC to promote STA's 2022 estimate of Unfished Biomass (122,000 to 136,000 tons -), and, accordingly, a higher threshold, until such a time as ADF&G can produce a less invalid estimate. You can find Sitka Tribe of Alaska's Unfished Biomass study beginning on p32 of this pdf set of public comments from the 2022 meeting.
4. It's never the wrong time to end sac roe fishing.

I think that's most of what I want to say about proposals for now. I may not write a whole lot here about the other proposals, but I want to make sure readers know where to find them. I've written a very quick and imperfect summary of all of the Sitka/Southeast proposals into a google doc. There are 20 southeast herring proposals in all. You can find a pdf of all of the Southeast Alaska herring proposals here. And, while I'm at it, for whoever's interested, here's Prince William Sound herring proposals, where it appears that there's plenty energy to fish again just as herring are starting to recover from all the bad things that happened to them there in the 1990's. I'm not sure I have anything meaningful to say about it other than 😦 but if I decide I do I'll let you know in these pages.

More soon!

Peter