Data from: Southern Ocean mesopelagic fish comply with Bergmann's rule

The applicability of macroecological rules to patterns in body size varies
between taxa. One of the most examined is Bergmann's rule, which
states that body size increases with decreasing temperature and increasing
latitude, although the rule is not universal and the proposed mechanisms
underpinning it are multifarious and lack congruence. This study considers
the degree to which Bergmann's rule applies to the Southern Ocean
mesopelagic fish community. We studied patterns in body size, temperature
and latitude across a 12° latitudinal gradient within the Scotia-Weddell
sector. Intra-specific Bergmann's rule was found to apply to 8 out of
the 11 biomass-dominant species in the family Myctophidae. The rule was
also apparent at an inter-specific level. Our study suggests that greater
attainable body size in this community is a necessary attribute to reach
colder regions further south. The adherence of these taxa to
Bergmann's rule enables such species to act as sentinels for
identifying the drivers and consequences of ocean warming on the Southern
Ocean ecosystem.