A first voyage: start with daylight
Start with a daylight catch, then make the next trip a different kind of fishing rather than a race for the most valuable hold.
Begin with Blue Mackerel: a daytime Coastal fish in The Marrows, caught by rod or trawl. Make finding it your first small objective; leave the grand tour for another voyage.
Try Cod next if you want another Coastal catch in the same water and window. It takes three cargo slots to the mackerel’s two, so leave room for a different silhouette in the hold.
For a change of habitat, consider Grey Eel. It lives in Shallow water in The Marrows and is active by day and night. Its page lists the rods and nets that reach its water, fastest first; choosing a new habitat is a reason to try a different piece of equipment.