Integrating new data streams (like eDNA)

[k-doering-NOAA]

This might be out of scope for now - but have we discussed when FIMS will consider new data streams for stock assessment? I was wondering this because of this recent publication, Baetscher et al. 2025 on incorporating eDNA into stock assessments and management (which I have only skimmed).

[Rick-Methot-NOAA]

An eDNA index is just like other indexes that lack scaling, like fishery CPUE. Best if the scaling factor for such indexes can be automatically created internally, but it could be a model parameter also. One hard issue for eDNA is the age-selectivity. Is each age's contribution proportional to body weight, or body surface area, or ??

[kellijohnson-NOAA]

@aaronmberger-nwfsc ❓

[aaronmberger-nwfsc]

Working on that question for an upcoming PFMC methodology review in October 2026. Basically, according to a select lit review, some species after a certain age tend to "shed" DNA in close proximity to proportionality with length/weight/age. But, in most other cases, there is considerable difference in that relationship, mostly skewed to smaller/younger individuals shedding more DNA per unit length/weight/age then larger/older individuals (i.e., ~according to the physical properties of the fishes surface-to-volume ratio). It will translate to interesting "selectivity" curves.

The methodology review will likely evaluate alternatives to investigate and scope out considerations, rather than formulating a specific answer to this question.