LaTeX warning explanation needed

[Rich Shepard]

On Thu, 14 Oct 2021, Rich Shepard wrote:

> Looks like the issue is with Keefer, et al. 2008.

Here's the biblatex entry for that paper:
@Article{Keefer2008,
   author   = {Keefer, M.L. and Boggs, C.T. and Peery, C.A. and Caudill, C.C.},
   journal  = {North American Journal of Fisheries Management},
   title    = {Overwintering Distribution, Behavior, and Survival of Adult Summer Steelhead: Variability among Columbia River Populations},
   year     = {2008},
   pages    = {81--96},
   volume   = {28},
   abstract = {Unlike most anadromous salmonids, summer steelhead Oncorhynchus
                   mykiss overwinter in rivers rather than the ocean for 6--10
                   months prior to spring spawning. Overwintering in rivers may
                   make summer steelhead more vulnerable to harvest and other
                   mortality sources than are other anadromous populations, but
                   there has been little systematic study of this life history
                   strategy. Here, we used a large-scale radiotelemetry study
                   to examine the overwintering behaviors and distributions of
                   26 summer steelhead stocks within the regulated lower
                   Columbia-Snake River hydrosystem. Over 6 years, we monitored
                   5,939 fish, of which 3,399 successfully reached spawning
                   tributaries or the upper Columbia River basin and were
                   assigned to specific populations. An estimated 12.\% of fish
                   that reached spawning areas overwintered at least partially
                   within the hydrosystem (annual estimates = 6.8--19.6\%),
                   while the remainder overwintered in tributaries. Across all
                   populations, later-arriving fish were more likely to
                   overwinter in the hydrosystem; overwintering percentages
                   ranged from less than 1\% for fish tagged in June to over
                   40\% for those tagged in October. Proportionately more
                   interior-basin steelhead (Clearwater, Salmon, and Snake
                   River metapopulations) overwintered in the hydrosystem than
                   did fish from lower-river populations. Steelhead were
                   distributed in mixed-stock assemblages throughout the
                   hydrosystem during winter, usually in reservoirs closest to
                   their home rivers but also in nonnatal tributaries.
                   Overwintering fish moved upstream and downstream between
                   reaches in all months; a nadir occurred in early January and
                   peak egress into spawning tributaries was in March. The
                   estimated survival to tributaries was higher for fish that
                   overwintered in the hydrosystem (82\%) than for fish that
                   did not (62\%); this difference was largely attributable to
                   low winter harvest rates. Our results suggest that large
                   main-stem habitats, including reservoirs, may be widely used
                   by overwintering summer steelhead. The complex migration
                   behaviors of steelhead indicate both the potential for
                   adaptation and possible susceptibility to future river
                   environment changes.},
   keywords = {fish, salmon, steelhead, trout, rivers, Columbia River, distribution, behavior, survival, adults},
}

Are the '%' symbols not correctly escaped?

Rich