  Using a sample of 67 galaxies from the MIGHTEE Survey Early Science data we
study the HI-based baryonic Tully-Fisher relation (bTFr), covering a period of
$\sim$one billion years ($0 \leq z \leq 0.081 $). We consider the bTFr based on
two different rotational velocity measures: the width of the global HI profile
and $\rm V_{out}$, measured as the outermost rotational velocity from the
resolved HI rotation curves. Both relations exhibit very low intrinsic scatter
orthogonal to the best-fit relation ($\sigma_{\perp}=0.07\pm0.01$), comparable
to the SPARC sample at $z \simeq 0$. The slopes of the relations are similar
and consistent with the $ z \simeq 0$ studies ($3.66^{+0.35}_{-0.29}$ for $\rm
W_{50}$ and $3.47^{+0.37}_{-0.30}$ for $\rm V_{out}$). We find no evidence that
the bTFr has evolved over the last billion years, and all galaxies in our
sample are consistent with the same relation independent of redshift and the
rotational velocity measure. Our results set up a reference for all future
studies of the HI-based bTFr as a function of redshift that will be conducted
with the ongoing deep SKA pathfinders surveys.

Astrophysics of Galaxies