Joseph Manning Hatchery Tour

Type: Nontidal
Region: Sourthern
Location: Joseph Manning Hatchery

The Joseph Manning Hatchery in Southern Maryland has been used for decades by the DNR Fisheries Service to propagate many species of warm water and tidal fish for stocking. Currently, the hatchery is a nursery for American and hickory shad, largemouth bass, crappies, hybrid sunfish and is a holding facility for Atlantic sturgeon. Each of these species caries its own success story and those accomplishments can be found on the DNR website at http://dnr.maryland.gov/fisheries/hatchery/index.asp.

One notable accomplishment from this location is the recovered and vibrant striped bass fishery of Chesapeake Bay. Recently, I had a chance to tour the facility and meet the dedicated hatchery team that looks after the hatchery. I learned bout the successes and some of the challenges that affect those efforts.

When I arrived, as a guest of Brian Richardson, who is in charge of all the hatcheries in Maryland and the many restoration projects underway, we were greeted by Dave Sien, the Hatchery Manager who was concerned with an abundance of largemouth bass fry and what to do with them. A decision was made on the spot to stock the fry later that day in two rivers on the Eastern Shore.

After that, we toured the breeding ponds (29 are used to raise fish – 1 is the freshwater reservoir). Don Pritchett, the Production Manager showed me a nest box, which is not much more than a square box filled with a layer of golf-ball size rocks, where the largemouth bass lay their eggs. The nest boxes are used successfully in the plastic-lined ponds. We then visited a natural-bottom pond where several bass had fanned out a large nest sites and the males was guarding the fry. (Note: Some of the ponds are lined with plastic – a recent project - but the majority of the ponds are natural clay bottoms)

There was a discussion about the success of the 'bloom' or the available food in the ponds. Micro-organisms called daphnia are stocked as food for the tiny bass and the success of the food's survival is crucial to the survival of the bass fry. All was well with the bloom despite the abundance of the recent rain.

I noticed what I thought were tiny bass on one of the nests and was informed that I was looking at 'fairy shrimp'. Fairy shrimp – a wild denizen of the ponds compete with the bass fry for daphnia until the bass reach a size large enough to prey on the shrimp. However, another tiny critter creates bigger challenges – the clam shrimp.

The clam shrimp is a tiny hard-shelled shrimp that is a denizen of vernal pools. In other words it can survive through a dry season and return when the pool refills with water in the spring.

The clam shrimp can completely muddy a hatchery pond and drastically cut spawning success. Don told me of his ongoing battles with the clam shrimp.

Just when I thought the two shrimp species were a tough act to follow, I learned about water net algae. Imagine a gill net designed to trap tiny fish fry only a half-inch long. That's water net. The algae can trap hundreds of fry during the growth phase while they are in the pond and affect spawning success. Again the bass are the most susceptible.

I asked if I could see the fairy shrimp, clam shrimp and water net. In a few moments Brandon Kell, a Fisheries Biologist came in with a quart jar filled with dozens of both kinds of shrimp and a strand of water net, which has the look and feel of nylon netting. I understand what challenges the hatchery crew members are facing to bring about a successful spawn.

It was time to go inside. Rows of water-filled concrete runs, large tanks and tubs, jars of eggs and a maze of pipes greeted me. I saw a tub full of adult hickory shad whose eggs were being collected. I saw a run full of bass fry and the daphnia they were feeding on. In the back there was a large pool with immature Atlantic sturgeon. It's hard to imagine a 7-foot-long fish as 'immature'. The sturgeon breeding program is being developed slowly despite the difficulty of waiting for the fish to mature to 15 years of age before they can reproduce.

Then I saw a big tank full of hickory shad fry immersed in a yellow liquid. "That's our chemical tagging process" explained Brian. We use tetracycline and immerse the fish in it on different days of their life cycles. These fish a re slated for immersion on day three, day six and day ten. The otolith (a structure in the ear of the fish - the otolith grows in rings like the growth rings of a tree) of the fish absorbs the dye each time and a pattern is forever recorded inside the fish. Records are kept and later, when sample fish are collected by electrofishing or other methods, we collect the otoliths and examine them under a microscope with ultraviolet light. The otolith grows in rings like the growth rings of a tree. When the UV light displays the pattern of the chemical tag, we can tell which batch of hatchery fish the samples came from

"Want to look at some eggs?" asked Dave Sien. "Sure" I replied. I was escorted to the lab where Sarah Rinn, a Fisheries Technician was peering into a microscope. The glass slide she was looking at contained tiny hickory shad eggs. She was peering at each egg to determine whether it was a living fish or had failed to survive. Fortunately, the winners outnumbered the losers. Another slide was brought in and I was permitted to see the difference in the size of hickory verse American shad eggs and actually see the living fish wriggling inside the translucent eggs. Very cool.

After the tour, the discussion with Brian turned to the coldwater hatcheries in western Maryland and the challenge to successful trout rearing efforts presented by whirling disease.

You know, I learned a lot on my tour about the ongoing challenges that nature presents to our restoration efforts. I also learned about the dedication and tenacity of the hatchery staff to build and rebuild our fisheries to sustainable populations.

Photo 1:
The good, the bad and the ugly... Hatchery Production Manager Don Pritchett (good) with a jar containing largemouth bass fry (good), daphnia (good), fairy shrimp (bad), clam shrimp (very bad and ugly) and water net algae (the ugliest).

Photo 2:
An 'immature' 7-foot Atlantic sturgeon will grow to hopefully reproduce in the Joseph Manning Hatchery

Tags: Sturgeon, Largemouth bass, Hatchery, American and hickory shad, largemouth bass, crappies, hybrid sunfish