Friday, May 4, 2018

Circling Back: Northern Pike at TPS

An awesome GoPro perspective of TPS's fish, two weeks after their move to Toledo (5/4/18); they are about 10 weeks
old in this image and average about 5" in length (although they range from 4-7")

(Written 5/9/18: I have been getting a lot of inquiries as to the status of this project, so I am circling back to provide an update.) Back in early March, I explained how a budding collaboration with Toledo Public Schools Natural Science Technology Center had evolved into an aquaculture project involving the rearing and (hopefully) ultimate release of fingerling northern pike into the waters of the marsh. Here's a progress report.

The tank that I sourced for TPS is a 300-gal, self-contained
recirculating system with an additional 100-gal capacity
for course and enzymatic water treatment
(the two vertical drums to the right of the circular tank)
Step 1 was determining what infrastructure the lab needed to support such an undertaking. The image to the right depicts our ultimate set-up.

Step 2 involved finding a willing and able outside partner, not only to source the fish but to educate us on the finer points of raising pike that are just 3-6" long. Very few hatcheries "tank raise" northerns -- meaning grow the fish indoors. The ODNR has suspended northern pike production entirely (to focus on species that have a broader geographic impact). Private hatcheries and most regional state hatcheries that deal with northerns hatch the eggs and then release the tiny fry into "growing ponds" when they are half the size of a penny (i.e., about immediately). This simplifies the process on one hand in that the developing fingerlings can feed on zooplankton and size-appropriate food items. They are then re-harvested at a target size and stocked into other waterways -- typically in the fall. This method wasn't an option for us, so a fortuitous cold call to the New Jersey DEP, Division of Fish and Wildlife proved to be the break that I/we needed.

I am so glad that I got the opportunity to visit the hatchery in Hackettstown, NJ in person -- not only was the history of the 100+ year-old facility impressive, but so was the modern rearing room that I visited (above, right), where literally hundreds of thousands of northern pike fingerlings were growing before my very eyes 

Step 3 proved to be more challenging than I expected -- namely getting the fish from western NJ the 521 miles to the lab in Toledo. It turns out next-day airing 200+ fish, albeit 3-4" fish, isn't as easy as one might think. And while we thought we had a taxi service setup (capitalizing on a cousin of mine driving through at what seemed to be just the right time), ultimately, I ended up taking a drive myself.

Tyler counting out ~75 fingerlings
into each ~10-gal aerated cooler
Heavy rains had put a hold on our tree planting efforts at the property, so I had to take advantage of my window of opportunity. I left late-afternoon on a Thursday (4/19), got to a hotel within 15 minutes of the hatchery before midnight, and was at the facility gate by 6:30 am to meet an unbelievably accommodating hatchery crew supervisor for a quick tour, orientation, and fish transfer.

My visit was way too short, but I learned a lot in a hurry. I was surprised at how similar their set-up is to what we have now established at TPS. They, too, utilized 300-gal poly tanks. The main differences are (1) their tanks utilize a flow-through system of local, spring-fed water, and (2) they are raising 3,000 fingerlings per tank (not 200 like we are). The good news is, we have room to grow!

We are trying to mimic what they do exactly -- down to the exact auto-feeder and dry feed that we are offering. Seeing this equipment in action not only built understanding but confidence.

I was really overwhelmed at how incredibly friendly, informative, and eager to collaborate my primary contact (Tyler Tressler) and his Hatchery Superintendent (Craig Lemon) were and continue to be. It gives me high hopes that this project will be successful this spring, and hopefully into subsequent springs.

Me with Tyler posing in front of three coolers and 227 fish,
just before departing for a 500+ mile return trip to Toledo
(amazingly, we didn't loose a single fish!)
So, Step 4 has been the really fun part -- transitioning the juvenile fish to their new (temporary) surroundings in the TPS lab. So far, so good. We anticipated up to 20% mortality due to adjustments to new water chemistry. We also have to expect some losses to escape (jumpers) and cannibalism.

The fact is, there is plenty of art to this science, so we have had to feel our way through a bit. But I am really pleased with where things stand as of today. We have lost fewer than a dozen fish to water quality-related issues. We have also eliminated the possibility of casualties due to jumping by making some modifications to the tank. Now, our challenge is to adjust the quantity and frequency of our feeding so that these little buggers will stop eating each other! Man, are they predators. [Aside: Dry feed is offered in very small quantities every 5 minutes, 24 hours/day in the hatchery to try to maximize growth while minimizing the pike's predatory instinct. We are now feeding every 15 minutes, but because we only have ~200 fish in our tank, I am constantly trying to feed enough without feeding too much -- too much leads to deteriorating water quality.]

Most importantly, the students, staff, and even the TPS administration have taken a real interest in the project. To date, the fish have received visits from the Toledo's mayor, local media, and many other visitors to the lab. I said from the onset, even if we end up with ~100 healthy fingerlings to release into the marsh, this first iteration will be a tremendous success. Beyond the numbers, we are connecting dots for people -- how do fish relate to wetlands, and how do wetlands relate to a better quality of life.

We're getting there. We hope to release (Step 5!) in the next three weeks. To be continued . . .

Fittingly, Roy captured this ~24" male northern this past week on the marsh side of our West Pump
(right where I staged the PhotoShop picture in my March 5 post);
this marks the first confirmed pike on the property since we started our work -- it likely came in back in April when
a strong NE storm temporarily pushed bay water over and around our aging pump structure;
it was at the pump because the water temps are probably telling it to head back to the Bay -- pretty exciting

P.S. Here's my first crack at some GoPro video. I plan to do some more to capture feeding behaviors. I'll shoot to post soon!