Explore Kauai Scuba

Right after dropping in for our dive at Lehua Crater/ Ni’ihau around ten male monk seals suddenly swarmed into the area out of nowhere. A young seal looked desperate for help, locking eyes with Captain Nick near the boat before the males attacked, biting its back and flipping the young seal.

I contacted NOAA right away to report the encounter. Before seeing the footage they explained that the young seal was likely female. But after they reviewed the footage I sent in it looked like a 1-2 year old male. This can happen in areas where the sex ratios are skewed. During these intense mobbing events, females can get their backs ripped up severely enough to die. In those critical situations, NOAA will intervene and bring them to the Marine Mammal Center on Big Island for rescue and rehab!

One cause of Hawaiian monk seal decline, especially during the 1980s and early 1990s was due to male aggression. This aggression can lead to severe wounds and death. There are two main types of male aggression that are relatively common. The first is groups of males mobbing other male and female seals. This aggression is likely due to a skewed sex ratio of more males than females in the monk seal population. The second is males attacking recently weaned pups. It has been attributed to numerous deaths of both male and female juvenile seals, particularly in the NWHI, which poses severe consequences to the recovery of the species when young, healthy, or reproductively viable seals are removed from the population.

While nearby Niʻihau has many mothers and pups, researchers actually don’t know why Lehua Crater attracts such a heavy concentration of males.

The seals slowly fought their way toward the side of Lehua Rock, and we saw the young seal make it onto the island, seemingly unharmed! Direct NOAA interventions in combination with the Marine Mammal Center are responsible for saving nearly 30% of the entire Hawaiian monk seal population alive today!