Heidi Wigman: Fisheries Sciences, June 8, 2015

NOAA Teacher at Sea
Heidi Wigman
Aboard NOAA Ship Pisces
May 27 – June 10, 2015

Mission: Reef Fish Survey
Geographical area of cruise: Gulf of Mexico (24°29.956’N 083°320.601’W)
Date: June 8, 2015

Weather: 83° @ surface, E-SE winds @ 10-15 knots, seas 2-3 ft, average depth 123m

Science and Technology Log:

NOAA’s mission is three-fold: science, service, and stewardship.  By utilizing fisheries, hydrographic, and oceanographic scientists in the field, NOAA’s goal is to understand and predict changes in climate, weather, oceans, and coasts, while also putting forth a conservation effort towards coastal and marine ecosystems. This knowledge is shared with businesses, communities, and people, to inform on how to make good choices to protect our fragile earth.

The specific mission, for our current voyage, on the Pisces, is to survey fisheries at pre-determined sites throughout the Western portion of the Gulf of Mexico. The data from these surveys will be brought back to the lab in Pascagoula, Miss. and analyzed. Then determinations will be made for future surveys and studies. According to Chief Scientist, Brandi Noble, “These fishery independent surveys increase our knowledge of natural reefs in the Gulf of Mexico. We get a better picture of what’s down there and work with outside agencies to determine how to maintain the health of the fisheries.  Data gathered will be used in future stock assessments for the Gulf of Mexico.”

The methods used to gather data on this cruise are through the use of the camera array and the bandit reels.  The camera arrays are deployed at sites that have been mapped and sit at the bottom for a total soak time of 40 minutes.  This footage is analyzed and processed by scientists to determine what the conditions of the reef are and the species of fish present in the area and their abundance.  This gives a partial picture, but to get a complete and accurate report, fish need to be studied more closely.  The “Bandit Reels” provide a more hands-on approach and allow the scientists to get data on sex, maturity stage, and age of species.  Some of the fish are released after some initial measurements, but the commercially important species are dissected and samples are taken for further lab analysis.  Initial measurements made with anything brought aboard include total length (TL), fork length (FL), standard length, SL (from nose to caudal fin), and weight.

A closer look at the data allows scientists to make predictions on fish populations and growth over time.  Some of the data we got on this trip were for the Lutjanus campechanus (red snapper) and for the Pagrus pagrus (red porgy).

There are several ways to disaggregate the data to determine differences and similarities based on region, time, species, etc.  For our purposes, we’ll make some observations involving probability, proportion, and statistics.

Math Problem of the day: You are a scientist and have brought data back from the Gulf of Mexico to analyze in your lab.  You have three tasks: a) to get an average fish size based on weight (species specific) b)  to determine what the proportion is of the Standard Length to the Total Length of each species (hint: ratio of SL/TL; find average) c) determine the theoretical probabilities that the next Red Snapper will be  >1,100g, and that the next red Porgy will be <1,000g (hint: how many times does this happen out of the total catches?)

Coming Soon . . . Meet some of the crew behind the Pisces

Previous Answers:

Trigonometry of Navigation post: 18 m/s @ 34°SE

Bandit Reels post: about 14.6 nautical miles

The STEM of Mapping post: layback = 218m, layback w/ catenary = 207m

Underwater Acoustics: about 163 sq. meters

SCUBA Science: letter group A