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Earth Science Applications Travelogue: Day 6: Friday May 16
May 16, 2014

[image-51]Early this morning efforts were made to deploy the S10 net at a station in the east central Gulf near the loop current. Seas remain moderate to rough and deploying the net was difficult. No Bluefin larvae were found and a small tear developed in the upper portion of the net near where the net hooks into a metal frame. Sarah Privoznik, who is the manager for Dr. Lamkin’s NOAA lab and a graduate student at the University of Miami, displayed her sewing skills to repair the net tear.

Winds remain about 20 knots from the SW and seas are 5-7 feet, so we are in a holding pattern until better weather hopefully later this afternoon. Early this afternoon I assisted Lamkin/Chief Scientist and Justin Luca, an undergraduate at the University of Miami with deployment of a World Ocean Circulation Experiment (WOCE) drifter. The WOCE drifter provides a platform for measurement of surface drifts, which can be used to determine residence time for a particular region of the ocean.

[image-67]These type data help to both determine areas for sampling and can provide details on currents in areas where Bluefin tuna larvae are found that will inform future sampling efforts. Drifter data is archived on the ARGOS global environmental monitoring and tracking system and can be used to validate models, provide surface truth for some satellite data and provide initial fields in climate prediction models.

During the cruise I am sharing a stateroom with Dr. Joel Llopiz, who is an external collaborator of the NOAA researchers on board. He is a faculty member at Woods Hole Oceanographic Institution (WHOI), and is interested in the planktonic food webs of the open ocean and how bluefin and other tuna larvae fit into those food webs. He has shown that tuna larvae in the nearby Straits of Florida have very narrow and specific diets, often consuming only one type of zooplankton prey type from the many types that are available to the larvae. He is freezing larvae as we catch them and will then perform an advanced stable isotope analysis on them. He says the results will shed light on what is at the base of the food web (the primary producers at ‘the bottom of the food chain’) as well as where tuna larvae fall in the food chain, which will change as the larvae grow and change their feeding habits.

[image-83]A fascinating fact about tuna larvae is that they are one of the very few groups of fishes that eat other fish larvae when they themselves are larvae. They begin exhibiting this behavior (called piscivory) at sizes as small as 5 millimeters, and sometimes consume their own species (cannibalism). At slightly larger sizes, it looks like they even have to feed on other fish larvae in order to survive -- the big, nutritious meals are the only things that can fuel their rapid growth and high energy demands. His stable isotope analyses, which will complement those of collaborator Raul Laiz (also aboard and research highlighted in the May 13 blog), will help show how well larvae are finding other fish larvae to feed upon. Joel received support for his participation from the Ocean Life Institute at the Woods Hole Oceanographic Institution.

[image-99]Several interesting birds have used our vessel to rest during the stormy weather. One was a seagull that the crew watered and fed some crackers to aid him in his journey. Another smaller bird was observed on the top deck and Joel (who has interest and knowledge of bird species too) identified him as a Northern Parula that was likely migrating. Hopefully both of our feathered friends will survive the windy weather to reach their destinations.

Looking to the weekend we are all hoping for calmer seas and much more sampling activity. On board ship with the 12 hour on and 12 hour off shifts 7 days a week schedule, each day is very similar and you tend to forget the day of the week or whether it is a weekday or weekend. Thoughts are more focused on the work schedule, what needs to be done to complete sampling, meals and resting off shift.

Best wishes to all for a great weekend!

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Repairing a tear in the S10 net.
Sarah Privoznik, manager for the NOAA lab and a graduate student at the University of Miami, repairs a tear in the S10 net.
Image Credit: 
Maury Estes
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John Lamkin and Maury Estes deploy a World Ocean Circulation Experiment (WOCE) drifter.
John Lamkin and Maury Estes deploy a World Ocean Circulation Experiment (WOCE) drifter.
Image Credit: 
Maury Estes
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Daily planning aboard the F.G. Walton Smith
Daily planning aboard the F.G. Walton Smith.
Image Credit: 
Maury Estes
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A seagull stops aboard for some crackers and water before continuing his journey.
A seagull stops aboard for some crackers and water before continuing his journey.
Image Credit: 
Maury Estes
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Page Last Updated: May 16th, 2014
Page Editor: Brooke Boen