Saving the Hawaiian Monk Seal: The How and Why

blog post photo
Dash Masland is a Marine Biologist and National Geographic Young Explorer Grantee, whose passion has been marine mammal conservation for practically her entire life.

The Hawaiian monk seal is the most endangered pinniped in the U.S. With a population of around 1,100 animals, it is one of the most endangered marine mammals in the world.  There were two other species of monk seals, the Caribbean monk seal, which has been declared extinct, and the Mediterranean monk seal, which is considered the most endangered pinniped in the world with less than 600 remaining.  With only around 1,100 Hawaiian monk seals left and the population decreasing at 4% a year, this charismatic and important marine mammal may not survive much longer.  

The monk seal was hunted by humans to near extinction in the 1800’s and the population has struggled to rebound.  It has been fully protected for the past few decades and their primary habitat in the North West Hawaiian Islands, where a population of around 900 animals live, has been protected as a marine park for years.  However, the monk seal is still not recovering.  It is thought that the main reason for the lack of recovery is that most monk seal pups are dying of starvation.  They have a less than 1 in 5 chance of making it to adulthood.

There is some good news, however.  The remaining 200 animals live in the Main Hawaiian Islands and their population is increasing. We need to fully understand the biology and ecology of this small population so we can better monitor its growth and help managers come up with effective strategies to allow seals and humans to coexist in the main Hawaiian Islands (MHI).  The foraging ecology of these animals is a critical component to understanding the prey and habitat needed by the only growing population of Hawaiian monk seals in order to identify areas of potential overlap between seal diet and human use of marine resources.  If we can help protect this population of monk seals, we may be able to help save the species from extinction.

blog post photo

On this expedition, I am going to use the latest technology in the field of marine mammal dietary studies to try and determine what the MHI monk seal population is eating.  We will collect seal scat (poop), a non-invasive sample collection method that causes minimal disturbance to the animals.  Traditionally, we then look for fish bones in the seal scat to see what the seals are eating.  However, sometimes certain fish species do not show up in the scat because their bones are so fragile.  So, what I will do is bring the scat samples back to the lab and analyze the samples for prey item DNA.  This method will give us more sensitive data on monk seal diet than we have been able to obtain in the past, thus giving us more insight into the diet of the Hawaiian monk seal in the Main Hawaiian Islands. Understanding the diet of marine mammals is tough to do since foraging is difficult to observe, so any information we can gain about this subject matter is valuable and will contribute to the conservation of the species.

Monk seals have been called “living fossils” because they are considered to be on the order of 14-16 million years old.  We certainly don’t want to watch them become extinct!  We hope that gaining insight into the diet of the small increasing Main Hawaiian monk seal population will help us understand this species better and help to conserve a highly endangered species, before it is too late.