NOAA Teacher at Sea
Chris Imhof
Onboard NOAA Ship Pisces
November 7 – 19, 2009
Mission: Coral Survey
Geographic Region: Southeast U.S.
Date: November 15, 2009
Science Log
Rough winds and big choppy waves coming around the Keys and into the Gulf Stream last night kept many awake and few of us with a taste of sea sickness. We make port in Jacksonville tonight and take on the ROV and more scientists. While making the first leg of this voyage it has been good to get to meet most of the crew and learn what they do and where they work on the Pisces; these include NOAA engineers, electrical and computer technicians, deck crew, stewards, and the NOAA Core officers. Since this is a maiden voyage, many of these people have worked on other NOAA ships – bringing their expertise and skills to get the Pisces up and working smoothly. Many of this crew will stay with the Pisces – operating the ship for NOAA scientists who come aboard to run experiments or do research in the months to come.
When I boarded the Pisces last Wednesday, the mammal scientists Tony Martinez and Lance Garrison were already on board testing equipment for an expedition this coming January – for detecting concentrations of sperm whale prey – from small fish to squid – acoustically and visually. Two pieces of technology they use are the EK60 Echosounder and ME70 Splitbeam:
1) The EK60 Simrad Echo-Sounder: This piece of technology uses a devices called a transducers that are located on the bottom of the Pisces to detect organisms. The Echo-Sounder operates on 4 frequencies – split beams of 200 and 120 khz (kilohertz) for shallow water detection – giving good data on zooplankton and small schools of fish, and the 18 and 38 khz frequencies which can detect fish, mammals and squid much deeper. The transducers issue a ping at each frequency every .5 seconds which bounce back creating a picture or vertical scatter. The scatter shown is a reflective signature – which the scientist use to identify what is below.
2) The ME70: The ME70 is brand new technology that uses a single high frequency – but based on amplitude reverberates from 80 transducers in a fan or swath -like shining a spot light down the water column. This gives another kind of visual image of what is below – especially the characteristics of the concentrations of zooplankton and nekton or schools of fish.
Tools and technology like this help scientists conduct surveys of marine species in deep and shallow waters, they can improve the way we estimate fish stocks – and the more it is used and tested can be a passive way to identify species in their habitats through their acoustic signatures.
An interesting aspect of this technology is the growing study of “swarm behavior” – understanding why schools of fish glide in precise synchronous movement. This field of study is becoming more important as we learn that self-organizing coordinated systems like schools of fish are extremely resilient and efficient. Mammal studies conducted by Tony and Lance aboard the Pisces may have larger implications in the future when looking at the behavior of crowds, or traffic on a highway, or how people move in a work place.
