Aquaman's ability to lead an aquatic army against Orm, including the fearsome creatures of the Trench and the Karathen, demonstrates the true power of his ability to communicate with marine life.

Source: https://screenrant.com/dceu-justice-leagueheroes-most-impressice-power-display/

The movie has also been described by Wan as a "bromance action adventure," primarily exploring the relationship between Arthur and Orm (Patrick Wilson), which may mean Mera and Aquababy won't be prominently featured.

Source: https://www.cbr.com/rumor-aquaman-scene-removed-walkouts/