10.5061/DRYAD.G1JWSTQQ1
Knight, Nicole
0000-0001-9256-242X
McGill University
Guichard, Frederic
0000-0002-7369-482X
McGill University
Altieri, Andrew
University of Florida
A global meta-analysis of temperature effects on marine fishes’ digestion
across trophic groups
Dryad
dataset
2020
FOS: Biological sciences
Natural Sciences and Engineering Research Council
https://ror.org/01h531d29
McGill University
https://ror.org/01pxwe438
Smithsonian Tropical Research Institute
https://ror.org/035jbxr46
2021-12-26T00:00:00Z
2021-02-27T00:00:00Z
en
https://doi.org/10.1111/geb.13262
560270 bytes
3
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Aim: The temperature constraint hypothesis proposes that marine
herbivorous fishes are rare at high latitudes relative to carnivorous
fishes because low temperatures impair the digestion of plant material. To
test this hypothesis, we compared the effects of temperature on the
digestive performance and investment of marine fishes across trophic
groups. Location: Global marine ecosystems. Major Taxa Studied: Marine
fishes. Methods: We analyzed data from 304 species consuming a range of
diets to quantify the effects of temperature on three indicators of
digestive performance and investment: gut passage time, absorption
efficiency, and gut length. Results: Decreasing temperatures increase gut
passage time in fishes consuming macroalgae more than fishes consuming
other fish or invertebrates. Low temperatures do not impair absorption
efficiency in fishes regardless of diet, but herbivores have lower
absorption efficiencies than carnivores overall. Gut length decreases with
decreasing temperature in all trophic groups. Main Conclusions: Our
analyses reveal limited evidence to support the temperature constraint
hypothesis. Low temperatures slow digestion more in fishes consuming
macroalgae than those consuming animal prey; however, this may not reflect
a meaningful disadvantage for herbivores but rather could be explained by
greater representation of fishes relying on microbial fermentation at high
latitudes. Herbivorous fishes absorb nutrients and energy from their food
in similar proportions regardless of temperature, contrary to the
expectations of the temperature constraint hypothesis. Decreased gut
length was associated with decreasing temperature across all trophic
groups, likely due to improved food quality at high latitudes, which
should benefit all trophic groups by reducing their required investment in
gut tissues. Altogether, our findings run counter to the general
hypothesis that low temperatures disadvantage the digestion of plant
material and suppress the diversity and abundance of herbivorous fishes at
high latitudes.
Literature search and data collection Eligibility criteria For an estimate
of gut passage time, absorption efficiency or gut length to be included in
our meta-analysis it had to have the following characteristics: Taken from
marine or estuarine fish species Taken from non-larval individuals Not
taken from species that are strictly detritivorous or corallivorous Not
taken from individuals fed an artificial diet with optimized composition
for nutrient uptake/digestion (i.e., as found in many aquaculture studies)
Not taken from individuals force-fed food items not typically consumed in
the wild and In the case of gut length, reported some metric of body
length or size. We note that there exists a large body of literature on
the “gastric evacuation rates” (the rate at which food leaves the stomach
and enters the hindgut) of carnivores, which was developed as a method for
indirectly estimating feeding rates by quantifying the minimum amount of
time required for stomach clearance between meals (Bromley, 1994). We
chose not to include this data in our analysis because: a) almost no data
on gastric evacuation rates exists for herbivores so we could not make
valid comparisons between trophic groups, and b) gastric evacuation rates
have been estimated using a wide range of methods and models, and it is
unclear under what circumstances comparisons between such models is
meaningful (Bromley, 1994). Gut passage time has been quantified for both
herbivores and carnivores and is a more easily comparable metric.
Information sources and search We searched Web of Science, JSTOR, and
Google Scholar. We also included data that were found in relevant review
papers and in publications that cited, or were cited in, the papers
discovered in our database search, as well as relevant papers found
incidentally. Altogether, we included papers published between 1958 and
March 2020. All search term combinations included marine and fish, as
well as the following combinations of additional search terms (but not all
search term combinations were used for all databases): assim*,
assimilation eff*, absorption, absorption eff*, “absorption efficiency”,
“assimilation efficiency”, excret*, egest*, conversion, “gut length”, “gut
morphology”, gut passage, gut transit, “gut passage time”, “gut transit
time”, digest*, digest* + temperature. We initially excluded studies if
their titles or abstracts were not relevant, then checked the remaining
studies for data that met the eligibility criteria described above. By
the end of this process, 99 studies were eligible for inclusion in the
meta-analysis. Data collection Data were extracted from
text, tables, and figures in the accepted studies. We collected
temperature and diet as predictor variables, as well as body length, since
many biological traits scale with size (Brown et al., 2004). However,
metrics of body size in reported in collected studies varied widely.
Metrics included standard length, total length, and fork length, these
were further divided into average values, median values, maximum/minimum
values, or no reported values. Whenever possible, we used the average
body size; if this was not provided, we used the mid-range (maximum –
minimum / 2) body size provided. We did not distinguish between standard,
total and fork length. If fish mass but not length was reported, we used
published length-weight relationships for the species in question to
calculate fish length. These instances are noted in the raw data. Ambient
temperature was likewise not always included in all the studies included
in our dataset, particularly for estimates of gut length. We supplemented
these datasets by extracting the date and location of data collection from
the study, and used that data to find the local sea surface temperature
(SST) at the time of sampling from the COBE SST data provided by
NOAA/OAR/ESRL PSD via http://www.esrl.noaa.gov/psd/. On the rare occasion
that the specific collection period was not included in the publication,
we took the average temperature of the location for five years preceding
publication of the data. These instances are noted in the data.
See README.txt.