snake mackerels
... that adult and juvenile snake mackerels both make daily vertical migrations, but in opposite directions?
... that adult and juvenile <b id="mwDtE"><a href="./Snake_mackerel" id="mwDtI" rel="mw:WikiLink" title="Snake mackerel">snake mackerels</a></b> both make <a href="./Diel_vertical_migration" id="mwDtM" rel="mw:WikiLink" title="Diel vertical migration">daily vertical migrations</a>, but in opposite directions?