Tuesday, June 2, 2015

Iceberg Invasion!

Over the past couple of days icebergs have surrounded the station. It's very calm with very little wind and there's no telling how long they will be around.  At the moment the R/V LM Gould is a couple of miles away "mowing the lawn".  They can't tie up because the icebergs are blocking the pier. 

Beautiful 'bergs though....

Wednesday, May 6, 2015

Humpback whales in the Neumayer Channel

On the way back to Palmer Station we saw humpback whales in the Neumayer Channel.... there really are no words (or video) to do it justice... but here you go.Click on this link to watch the video of a momma whale and her calf

White-blooded icefish really do have "white" blood!

Now, compare the gills of the white-blooded icefish, Chaenocephalus aceratus to the red-blooded Notothenia coriiceps: the gills of the icefish look white!  Icefish do not have red-blood cells and do not make the oxygen binding protein hemoglobin that is the protein responsible for giving blood its characteristic red color.  Hemoglobin binds oxygen and transports it through the body to the tissues that need it for aerobic metabolism.  Because icefish lack hemoglobin they carry only a fraction of the oxygen (~10%) a red-blooded fish carries. All the oxygen in the blood is dissolved in plasma, which is the fluid part of blood that is composed of water, proteins, small molecules and ions.

Icefish Chaeocephalus aceratus
Red-blooded Notothenia coriiceps

The gills of the icefish C.  aceratus appear white because the blood lacks hemoglobin-containing red blood cells.

The gills of the red-blooded fish N. coriiceps are red because this fish species has red blood cells that contain the oxygen binding protein hemoglobin.

We use otter trawls and fish pots to catch fish

We arrived around 9:00pm on Thursday and immediately started fishing.  We use two types of gear: otter trawls and fish pots. We fish at depths that range from ~150meters to ~200meters in depth. The icefish and the red blooded notothenioids are benthic; they sit on the bottom, which is why we need to do bottom trawls to catch them.

The otter trawl is being hauled up onto the deck.  The metal doors help to hold the net open while it is being pulled through the water. It takes about 20 minutes for the net to reach the bottom, we trawl for 15 minutes and then another 20 minutes to bring the net up to the surface.
Here you can see the entire net hauled up on deck; the  cod-end of the net is the part of the net that holds the fish that are caught. You can see the enlarged cod end that holds our catch. Where we were fishing we were hauling up a lot of macroalgae, so most of what is in the net is algae, not fish.

We set lines of four fish pots and fill a bait bag (the orange sack in the photo above) with mackerel and sardines.  We set the pots and haul them back up 24 hours later.   In each pot we generally catch 0-8 fish, and we set a total of 16 pots.  We use the fish pots to catch primarily the red-blooded Antarctic fish, Notothenia coriiceps (below).

 The common name of N. coriiceps is the yellow belly rockcod.
When you lift the operculum and look in the gill chamber of a red-blooded fish you can see the gills.  The gills are red because of the presence of red blood cells that contain hemoglobin.  Hemoglobin is an oxygen binding protein that transports oxygen through the body.  The only adult vertebrate that do not have hemoglobin are the icefish, which is the group of fish we are studying.  I'll show a photo of icefish gills in the next post, but icefish do not have red blood because they do not have hemoglobin or red blood cells.

But, back to the fish pots.... When we haul up the pots, there are amphipods that are feeding on the bait.
The bait bags are covered with amphipods, which are a type of crustacean.
Below you can see a close-up of a bait bag; the amphipods have scavenged the "meat" off the mackerel and sardine bait, leaving only the skeleton... pretty cool, huh?

Monday, May 4, 2015

On the way to the fishing grounds

The view of Palmer at sunrise as we leave the station to go fishing.
We left to go fishing last Thursday and we headed up to Low Island (see Google Earth Map below), which is a 12 hour steam from Palmer. Also, if you click on any of these images, they should open as a larger version.

To get to Low Island we went through the Neumayer Channel, which is undoubtedly one of the most spectacular places on earth.

I made the Valdosta Daily Times....

I do not  know if this link will work, but the VDT picked up the press release done by VSU and printed it.  This link should take you to the article:  Article in VDT