Friday, January 30, 2015

Furunculosis Outbreak in Retrospective

Here's an article published this past spring for my Recorder Newspapers column. The furunculosis outbreak of late 2013 will not affect trout stocked this year, although only rainbow trout will be stocked.

Furunculosis changes trout season plans

By Bruce Litton

          Many of us became informed last fall of the fish disease, furunculosis, likely transmitted from a heron or herons to trout at Pequest Hatchery. Caused by a wild bacterium, Aeromonus salmonicida, it’s assumed the birds picked it up somewhere else, since the hatchery is groundwater fed. The infection altered some of the fall stocking program, and we wondered what lay ahead.

          The changes for this spring are far reaching, but there will be trout for Opening Day, Saturday, April 5th, and weekly stockings through May 2nd. However, to protect native, wild, and holdover trout populations, no trout will be stocked in Trophy Trout Lakes (Merrill Creek Reservoir, Round Valley Reservoir), Holdover Trout Lakes, (Clinton Reservoir, Lake Aeroflex, Lake Wawayanda, Shepherd Lake, White Lake), and some of the Trout Production Streams and waters directly connected to them too numerous to list. Information is available online under NJ Fish & Wildlife postings, among other sites.

          Most of our Highlands streams will receive a lion’s share of pre-Opening Day stocking. Since rainbow trout are resistant to this disease, although they may carry it, don’t expect many brook and brown trout. Furnuculosis is not a threat to human health, although it’s understandable if the thought of the fish’s infection is not appetizing. Only fish unexposed to the disease will be stocked in any Trout Production stream associated with wild, and perhaps also native, trout. Exposed trout, testing negative for the disease, will be stocked in Trout Maintenance streams. Put and take waters will get fish treated by medicated feed, but don’t expect to catch deformed trout, although some may be carriers of the disease. CO2 is the quick and painless method of eradicating the many unfit trout. This is the first outbreak of furnuculosis in Pequest Hatchery’s history, although it has happened in Pennsylvania hatcheries.

          “They (Pequest) raise way over 600,000 trout every year, but they’re still stocking 570,000,” Brian Cowden, Trout Unlimited Musconetcong Coordinator, said. “It’s a conservative plan, and they will not stock fish that test positive.” While the disease is not likely to spread in the wild, the possibilities are unknown. The Pequest Hatchery’s care is important.

          Trout-rearing raceways will be disinfected, and in the future, the state plans to rear furnuculosis-resistant brook and brown trout. For the time being, remaining trout are being vaccinated. Over the course of the next few years, rainbows will mostly replace the other two familiar species until the resistant trout are established.

          It’s disheartening to know that our reliable trout stocks have taken such an onslaught from perhaps a few ospreys and herons. However, three years ago when I began this column, I noted that hatchery reared trout have been shown to have smaller brains than wild fish, and this raises a point about hatchery susceptibility. Wild trout thrive and survive by so many more environmental variables than a straight, concrete, crowded raceway. It may be supposed that positive growth, and ultimately health, depends upon multifaceted environmental opportunities for animals of any species—including humans—to make choices and respond, have impulses and address situations, if any animal other than human addresses anything. I consider that the way a trout overtakes a streamer fly displays impetus from within the fish, not a purely responsive swipe, but an address is a rational consideration.

          I’ve been unable to find anything online about an entire wild, or native, trout stream waylaid by furnuculosis, although Susquehanna River smallmouth bass have suffered an epidemic due to low water and heat stress. Again, Aeromonus salmonicida is a wild bacterium. “Aero” implies that the disease is commonly transmitted by birds. Wild trout, salmon, even minnows, chub, pike, carp, bass, etc. get it. As a boy, I saw it on minnows in Little Shabakunk Creek, Mercer County, never infecting all the fish. Nature is resistant; simplified man-made spaces vulnerable. It reminds me of Michael Crichton’s science fiction debut The Andromeda Strain.  

          In any event, if it weren’t for hatcheries, the Highlands would have no wild browns and rainbows, although these populations have been established for many generations now. Nowadays, the trend is to remove dams from rivers like the Raritan and Musconetcong, and if two of the three dams on the Paulinskill River are removed, the population of wild browns will increase, since dammed flows warm in summer, and without dams, rivers run more in accord with springs that cool and clean them.

          So this Opening Day, appreciate your surroundings a little more than usual, knowing that wildness, freedom, and health go together. Let some of your own neuronal dendrites spread out a little wider than they would with four walls around you. takes you to a comprehensive article on salmon egg fishing.