Corroborated
Confirmed by multiple independent player-written sources, not yet by an official source or in-game evidence.
Lighthouse
The starting island where your boat crashes. Home to the lighthouse keeper and Spidercrab.
"Lighthouse" is now corroborated by two independent fish-list sources (Game8, Destructoid), which is why it's used as the canonical name here, a change from the earlier numbered-only placeholder. The beer-can quest / Crab Fishing Rod / Spidercrab sequence is separately well corroborated by guide-site walkthroughs and a gameplay video.
Related
Boss
Spidercrab
The first boss, guarding the starting island.
Rod
Crab Fishing Rod
The first purchasable rod, needed to catch more valuable creatures than the starting rod allows.
Bait
Free Lure
The starting bait, usable from Island 1 onward for the most common, lowest-value catches.
Bait
Hot Dog
An early bait tier used on Island 1-2, one step above the Free Lure.