Categorized | Environment

Expedition Granted! Studying the Hawaiian monk seal

Special to Hawaii 24/7 by Dash Masland

With the National Geographic Channel’s Expedition Granted competition one month behind us, I am in full swing on the planning of my expedition. In case you didn’t hear, Team Monk Seal took the win!

That means each and every one of your votes helped launch this project by helping me win an amazing $10,000 grant. So, first of all, thank you all so much. I truly appreciate all the support, enthusiasm and of course, the clicks! I literally, and figuratively, could not have done it without you!

Here’s where we are so far:

I am working with Jennifer Schultz who is an Affiliate Research Faculty at the University of Hawaii’s Hawaii Institute of Marine Biology (HIMB) and also Lead of the Hawaiian Monk Seal Genetics Program through NOAA Fisheries.

We are also working with Charles Littnan, who is the lead scientist for the Hawaiian Monk Seal Research Project in the Protected Species Division of NOAA’s Pacific Island Fisheries Center.

Together, the three of us are coordinating this project to study the diet of the Hawaiian Monk Seal using fecal DNA.

The first order of business for us is to select a fish species that we would like to look for in the diet of the Hawaii monk seals located in the Main Hawaiian Islands (MHI). There are two distinct populations of Hawaiian monk seals.

One is located in the Northwest Hawaiian Islands (NWHI), has a population of around 900 animals and is decreasing substantially each year. The other population is the MHI population with around 200 animals. This population is actually increasing.

The reason we are focusing on studying the diet of the MHI population is if we can fully understand what they are eating and help protect their food sources, and they in turn survive better then we may be able to help repopulate the species.

However, just because this project is focusing on the diet of the MHI population, does not mean that we are not interested in the diet of the NWHI population, because we are and their diet is being studied as well.

So, again, we need to pick a fish species to look at through fecal DNA. Traditionally seal diet is studied by looking at fish bones found in seal scat (poop). Fish ear bones, or otoliths, are collected and identified down to species level.

The problem with this is that some prey items don’t have otoliths (crustaceans, mollusks) and others prey items the otoliths dissolve too rapidly in the digestive tract of the seal and are therefore unidentifiable.

So, if there is a prey item we are particularly interested in, we can use DNA to see if the seal has eaten the prey item. We are in the process of determining which prey item we want to look at right now.

In the meantime, I am heading to Hawaii at the end of May for two weeks. Our first order of business is to head out into the field.

There was already a tagging trip planned, so I will be joining NOAA on the island of Molokai to help tag animals and to collect any fecal samples that may be deposited during tagging or opportunistically found. The fecal samples will be preserved and brought back to the lab. There are already additional fecal samples from the MHI preserved and archived.

Once back in the lab, a HIMB facility located on Coconut Island off of Oahu, I will have two tasks.

First, I will extract DNA from fish tissue samples; both the species we will look at and a wide range of others that we won’t be studying.

Second, I will extract the DNA from all the fecal samples we collected and have archived. This DNA will be deep frozen and shipped back to Maine.

Once home in Maine, I will work at the computer to design PCR primers. PCR primers are short segments of DNA that are designed to only bind to target DNA, or in this case, the fish species in question during a process called Polymerase Chain Reaction (PCR).

We then use PCR to make millions of copies of the target DNA which gives us enough DNA to be able to be able to visually determine if the DNA we are looking for in a sample is present or not.

I will then test my PCR primers in the lab against an array of fish tissue samples. I will be doing this work at Bigelow Laboratory for Ocean Sciences in the lab of Dr. Ramunas Stepanauskas. I need to make sure that my PCR primers will amplify the fish species that I want to look for, but no other fish species and definitely not Hawaiian monk seal DNA.

This is a pretty difficult task, but we are all up for the challenge.

Once I determine my PCR primers are successfully working, I will make a second trip back to Hawaii. This time I will be working at the Waikiki Aquarium with the captive Hawaiian monk seals. It is important to make sure that our PCR product not only works on fish tissue, but also on fecal samples.

So, we will feed the captive seals the fish in question and then will collect their fecal matter. We will then test the scat samples to make sure we can find the fish DNA in the seal scat of a seal that we know ate the fish.

And then … once this is all working … I will head back to Maine, and test all my field samples for the fish item in question. We will then know whether or not Hawaiian monk seals are eating the fish in question, which will in turn help us make important management decisions to help protect the Hawaiian monk seal from extinction.

Any questions? Just send me an email at dashmasland@gmail.com and I will post the question and answer at the bottom of my Website.

Thanks for listening and thanks again for all your support.

— Find out more:
www.dashmasland.com

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