Sharks
Sharks
[Cueball is sitting on a throne, talking to a minion who's not shown in the panel.] Minion: The prisoner escaped and is swimming toward the mainland! Cueball: Release the sharks. Minion: Yes, sir.
Minion: The sharks are swimming away. Cueball: They're escaping, too? Send sharks after them!
Minion: Now those sharks are swimming away. Cueball: More sharks. Minion: ...Sir, what's going on? Cueball: Prisoners, of course! Can't let 'em escape!
Minion: Sir, are you trying to turn Doom Island into a marine biology center? Cueball: Shark populations are in decline– Cueball: *ahem* Cueball: I mean, the world must fear us! Minion: Right...

This comic is a joke about the use of sharks in action movies. In these movies, sharks are often used to guard locations and dispense capital punishment. Since the idea of a guard shark is not practical, this comic suggests that villains raise sharks to help with declining shark populations in the oceans.
In this comic Cueball is an evil villain who rules over a "Doom Island." In addition to commanding minions and detaining prisoners, he keeps sharks to threaten prisoners. When a prisoner escapes the island, he orders his minions to "release the sharks." However, the sharks do not hunt the prisoner, but merely swim away. The comic jokes that Cueball is using fugitives as a pretense to help with declining shark populations, and that Doom Island is just a front for a marine biology center. Cueball maintains the whole "guard sharks" idea as a cover-up, so that his minions do not catch on to the real mission.
The title text plays on the idea that Cueball can't be openly concerned with his sharks' welfare without his minions catching on. He claims to be inspecting the shark cages. As a shark cage is normally used to provide protection for divers wishing to observe sharks up-close, they would not work well as cages to hold prisoners (which is their stated purpose). The comic implies that when he is "inspecting the cages" he is really performing a scientific study on the sharks, or simply observing them because he loves them.
Because a real villainous lair would have no use for shark cages, it follows that Cueball owns them solely for the purpose of gratifying his interest in his sharks, thus forcing him to keep up the pretense of the cages being of some help in preventing prisoners from escaping.
The shark issue is also one of the items on the chart of 1331: Frequency .
"Doom Island" is most likely meant to be a generic name for the villain's lair (a trope dating back to at least the first James Bond film, Dr. No ); however, a real island of this name exists in Indonesia.
In action movie trope from the '70s and '80s, evil villains use sharks to kill off enemies. Some examples are:
And in the James Bond series:
[Cueball is sitting on a throne, talking to a minion who's not shown in the panel.] Minion: The prisoner escaped and is swimming toward the mainland! Cueball: Release the sharks. Minion: Yes, sir.
Minion: The sharks are swimming away. Cueball: They're escaping, too? Send sharks after them!
Minion: Now those sharks are swimming away. Cueball: More sharks. Minion: ...Sir, what's going on? Cueball: Prisoners, of course! Can't let 'em escape!
Minion: Sir, are you trying to turn Doom Island into a marine biology center? Cueball: Shark populations are in decline– Cueball: *ahem* Cueball: I mean, the world must fear us! Minion: Right...
