  We present new spectroscopic observations of the Be/black hole binary MWC 656
obtained during the period 2015 - 2021. We measure the equivalent width of
H$\alpha$ (EW$_\alpha$), H$\beta$ ($EW_\beta$), and the distance between the
peaks of H$\alpha$ ($\Delta V_\alpha$), H$\beta$ ($\Delta V_\beta$), and FeII
($\Delta V_{FeII}$) lines. Combining new and old data, we find that:
  - the density of the circumstellar disc of MWC 656 ($\Delta V_\alpha$ versus
$EW_\alpha$ diagram) is similar to the Be stars. For the Be stars we find the
relation $\Delta V_\beta = 0.999 \Delta V_\alpha + 62.4$ km s$^{-1}$, and the
position of MWC~656 corresponds to the average behaviour of the Be stars. This
means that the presence of the black hole does not change the overall structure
of the circumstellar disc.
  - the periodogram analysis indicates modulation of $EW_\alpha$ with a period
$60.4 \pm 0.4$ days, which is identical to the binary orbital period. The
maxima of $EW_\alpha$ and $EW_\beta$ are around periastron (phase zero).
  - around orbital phase zero, $\Delta V_\beta$ and $\Delta V_{FeII}$ decrease
by about $30$ km s$^{-1}$. This suggests that we observe an increase of the
circumstellar disc size induced by the periastron passage of the black hole and
that the entire circumstellar disc pulsates with the orbital period with
relative amplitude of 10-20%. The observations also indicate, that the reason
for the black hole in MWC 656 to be in deep quiescence is a very low efficiency
of accretion ($\sim 2 \times 10^{-6}$).
