Jeff Miller: Fishing for Sharks and Fishes, September 6, 2015

NOAA Teacher at Sea
Jeff Miller
Aboard NOAA Ship Oregon II
August 31 – September 14, 2015

Mission: Shark Longline Survey
Geographical Area: Gulf of Mexico
Date: September 6, 2015

Data from the Bridge
Ship Speed: 9.7 knots
Wind Speed: 5.6 knots
Air Temp: 30.9°C
Sea Temp: 31.1°C
Seas: <1 meter
Sea Depth: 52 meters

GPS Coordinates
Lat:  N 28 06.236
Long:  W 095 15.023

Science and Technology Log
Our first couple days of fishing have been a great learning experience for me despite the fact that the fish count has been relatively low (the last three sets we averaged less than 5 fish per 100 hooks).  There are a number of jobs to do at each survey station and I will rotate through each of them during my cruise. These jobs include baiting the hooks, numbering and setting the hooks on the main line, hauling in the hooks, measuring and weighing the sharks/fish, and processing the shark/fish for biological samples.

Numbering the baited hooks

Each gangion (the baited hook and its associate line) is tagged with a number before being attached to the main line.


Number clips

A number clip is attached to each gangion (baited hook and its associated line) to catalog each fish that is caught.

After the line is deployed for one hour, we haul in the catch.  As the gangions come in, one of us will collect empty hooks and place them back in the barrel to be ready for the next station.  Other members of the team will process the fish we catch.  The number of fish caught at each station can vary widely.  Our team (the daytime team) had two stations in a row where we caught fewer than five fish while the night team caught 57 fish at a single station.

Collecting empty hooks

Empty hooks are collected, left over bait is removed, and the gangion is placed back in the bucket to be ready for the next station.

So far we have caught a variety of fishes including golden tilefish, red snapper, sharpnose sharks, blacknose sharks, a scalloped hammerhead, black tip sharks, a spinner shark, and smooth dogfish.  The first set of hooks we deployed was at a deep water station (sea depth was approx. 300 meters or 985 feet) and we hooked 11 golden tilefish, including one that weighed 13 kg (28.6 pounds).

Golden tilefish

On our first set of hooks in deep water, we caught a number of golden tilefish including this fish that weighed nearly 30 pounds.

We collect a number of samples from fishes such as red snapper and golden tilefish.  First we collect otoliths, which are hard calcified structures of the inner ear that are located just behind the brain.  Scientists can read the rings of the otolith to determine the approximate age and growth rate of the fish.


Otoliths can be read like tree rings to approximate the age and growth rate of bony fishes.  Photo credit: NOAA Marine Fisheries.

The answer to the poll is at the end of this post.

You can try to age fish like NOAA scientists do by using the Age Reading Demonstration created by the NOAA Alaska Fisheries Science Center.  Click here to visit the site.

When sharks are caught, we collect information about their size, gender, and sexual maturity.  You may be wondering, “how can you determine the sex of a shark?”  It ends up that the answer is actually quite simple.  Male sharks have two claspers along the inner margin of the pelvic fins that are used to insert sperm into the cloaca of a female.  Female sharks lack claspers.

Male female shark

Male and female sharks can be distinguished by the presence of claspers on male sharks.

Personal Log
After arriving at our first survey station on Thursday afternoon (Sep. 3), everyone on the ship is in full work mode.  We work around the clock in two groups: one team, which I belong to, works from noon to midnight, and the other team works from midnight to noon.  The crew and science teams work very well together – everyone has a specific job as we set out hooks, haul the catch, and process the fishes.  It’s a well oiled machine and I am grateful to the crew and my fellow science team members for helping me learn and take an active role the process.  I am not here as a passive observer.  I am truly part of the scientific team.

I have also learned a lot about the fishes we are catching.  For example, I have learned how to handle them on deck, how to process them for samples, and how to filet them for dinner.  I never fished much my life, so pretty much everything I am doing is new to me.

I have also adjusted well to life on the ship.  Before the cruise, I was concerned that I may get seasick since I am prone to motion sickness.  However, so far I have felt great even though we have been in relatively choppy seas (averaging about 1-2 meters or 3 to 6 feet) and the ship rocks constantly.  I have been using a scopolamine patch, an anticholinergic drug that decreases nausea and dizziness, and this likely is playing a role. Whether it’s just me or the medicine, I feel good, I’m sleeping well, and I am eating well.  The cooks are great and the food has been outstanding.  All in all, I am having an amazing experience.

Poll answer:  This fish is approximately nine years old (as determined by members of my science team aboard the Oregon II).

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