def _fix_ocean_basins_50_v5_0_0(self, df):
    """fix ocean basins 50 for naturalearth v5.0.0

    - Mediterranean Sea and Ross Sea is **no longer** split in two.
    - There are two regions named Great Barrier Reef - these are now merged
    - The numbers/ indices are different from Version 4.0!
    """

    p1 = df.loc[74].geometry
    p2 = df.loc[114].geometry

    # merge the two Great Barrier Reef polygons - 74 <<< 114
    poly = p1.union(p2)
    df.at[74, "geometry"] = poly
    # remove the now merged row
    df = df.drop(labels=114).reset_index()

    return df