The Broodling Grounds
are located on the seal clubbers' version of the Secret Island Volcano Lair
You creep up to the section of rocky coastline where the seal pups are frolicking, and regard them cautiously from behind a boulder. This may sound like cowardly behavior for a staunch Northern barbarian, but please take into account the fact that "frolicking", in this context, means "gleefully and violently tearing all the limbs off of, and then disemboweling, any of their number that look to be slightly weaker or inattentive".
Generally, hellseal broods reduce themselves down to about a tenth of the original population within the first few weeks after they develop their claws and fangs and leave the protection of their mothers. This leaves a small pack of extremely strong, fast, wily, and above all violent seal pups, who are also intelligent enough to recognize the fact that even if they managed to defeat one of their siblings, the fight would weaken them enough to make them easy prey for all the others. Thus, an uneasy truce develops (as well as a tendency to sleep with their eyes open), until it is time for them to leave the spawning grounds and stake out their own territories. This particular brood appears to be nearing that stage -- most of the pups are watching each other warily and growling when others get too close, and fights are breaking out only sporadically. Unfortunately, there are still quite a lot of pups here, meaning either the initial brood was astoundingly large, or the pups were all uncommonly strong. Since Gorgolok probably fathered all of them, either of these -- or both -- could well be the case.
The upshot of all this is, it's not somewhere to be shouting your battlecry and charging in, club upraised, without a damn good reason.