I just completed my third shift as a crew member aboard the good ship Sentinal and I enjoyed every minute of it.  Well, alright, not every single minute – there was the time when an extreme series of waves brought the starboard gunwale within inches of the water surface. As a landlubber I was a tiny bit horrified by this, but it was of no consequence to my shipmates Dr. Bruce Manny and Jim McFee. Bruce and Jim are fisheries biologists working with the U.S. Fish and Wildlife Service on a sturgeon monitoring program. The waves, as a matter of fact, were caused by our own wake as Bruce veered toward an orange buoy off of West Hennipen Point.

  On this particular day, the Detroit River around Fighting Island and the northern end of Grosse Ile was calm and only slightly cool. The buoy marked the southern anchoring point of a 250 foot trot line positioned to catch Lake Sturgeon from near the hard clay bottom.  On this particular pull, we ended up getting two of these magnificent fish on the line. The first was 4.2 feet long and weighed 26.4 pounds and the second was slightly longer and four pounds heavier. Both were measured, weighed and tagged before being released back into the cold emerald green water. By general fish standards these would be considered behemoths but by sturgeon standards they were completely average.

  Allow me to back up a moment and explain a few things. You may remember, if you are a regular reader, that I’ve taken you out on this trip before. If so, feel free to ignore the following details. Every year for the past few years, the USFWS crew has been out catching and tagging sturgeon on the big Detroit. They are monitoring the population and trying to build up a data base of information so that they can understand what makes this ancient fish tick. To catch these bottom feeders, the biologists put out six set lines each about 30 feet deep and equipped with 25 huge baited hooks spaced at 10 foot intervals. The bait consists of Round Gobies, those alien invaders who are abundantly available for just such a purpose. “This is the best use I can think of for these fish,” blurts out Dr. Manny. I agree with him. We both see the poetic justice of using a pesky alien to help out a rare native.

  The procedure is to hook the set line buoy, pull up the double pronged anchor, and slowly pull the line onto the deck. Each hook is detached from the line via a metal spring hook. It was my primary job to grab these hook-lines as they were pulled and keep them in a neat row along the edge of a big blue plastic barrel (here’s my work – nice eh?). When Jim returned the line to the water – after assuring the hooks are sufficiently baited – I handed them back to him one by one.  When a sturgeon came up on one of the hooks, of course, the real work began.

  We pulled up a total of six sturgeons- one each on the first two sets, and two each on the last two sets.  Each time the documentation procedure was the same. I was able to get a better view than previous trips because I was part of the process. 

  The first order of business is to lift the fish into a net cradle and weigh it. During this time, Bruce is writing down the numbers as Jim calls them out. “15.5” indicates a weight of 15 and a half kilograms. There are 2.2 pounds per kg, if you want to do the math. Our weights ranged between 6 ½ and 37 pounds. The total length was taken in millimeters from the tip of the snout to the tip of the upper lobe of the shark-like tail (which translated to a range from 35 inches to 55 inches). A shorter fork length is taken from the snout to the inside of the tail notch and then a “commercial” length from the back of the gill opening to the back of the anal fin. The girth was measured just behind the pectoral fins and ran from a mere 12 inches up to 22 inches.

  A uniquely numbered six digit tag called a Floy tag is inserted into the trailing edge of the dorsal fin – the small triangular fin just ahead of the tail. Accompanied by slight gristly sound, the tag is punctured through (with what looks to be a carpet needle!) and secured like a zip tag (see here). A radio tag, the size of a small pill, is then carefully inserted just behind the first back scute using a hollow syringe. The needle tip is daubed with a dollop of anti-biotic to make sure the small puncture heals properly.

  I thought my role significant when I was given the charge of reading off the frequency code that was called up on the hand held reader when it was passed over the post-implanted fish.  I enunciated every digit with professional clarity so that Dr. Manny could record it properly. I later found out that he already had these numbers on his sheets, having passed the reader over the electronic pills before they were inserted. My dramatic reading served only to confirm what was already known, but what the hey.

  The last part of the process involved cutting off the first spine of the left pectoral fin. By using a hack saw and a honking big knife, Jim was able to remove this 3 inch piece of fin with a minimum of blood. I will admit that the sound of saw rasping on hard cartilage does create a wince effect. This portion will be microscopically examined in the lab for a count of the annual rings that will provide an accurate age estimate. The severed spine is sealed into a small envelope upon which all the individual fish data is recorded (see here – note the super long number on the bottom line that I was responsible for reading).

  We slipped each fish back into the water within a few minutes of its capture – holding it captive on the steel deck only long enough to reap a harvest of valuable data from it.  Jim would gently lower the beast into the water and hold on for a while until it recovered sufficiently for release. Sometimes this took a minute or two, while other times the victimized fish broke free as soon as it hit the water.

  After the last set was complete, the Sentinel returned to the Wyandotte municipal dock and the gear was hauled ashore. We talked about the success of the day and the promise offered by the following morning.

  “You shoulda seen the fish we caught last week,” said Bruce when I expressed amazement at the 37 pounder. “That fish was so heavy,” he delivered like a set up line, “that it exceeded the capacity of our scale.” I glanced down at the scale to see that it was a 50 kg. unit, so I figured out and verbalized that it was over 110 pounds.  “Well over,” he added. “The snout hung out about this far over the front of the sling,” he said holding his hands about 18 inches apart, “and the tail hung out the same distance out the back. The girth was something like a meter.”  Given these dimensions, this sturgeon was one of those old school giants in the six foot plus category. Unfortunately Jim forgot his camera on that day, so the fish remains only as a statistical record.

“Sure,” I said in mock disbelief. “No picture, eh?”  “No, really,” they both retorted. Given the absence of eye winks, I was force to believe what they said was actually the truth.

  The potential of pulling up another one of these giants, or even re-capturing last week’s animal, will keep me coming back to the sturgeon boat year after year.

  Although the big fish are always the primary thrill, the other sights along the big river were satisfying as well. I’ll introduce a few of these in the next installment.