FWI has considerable experience in the re-engineering of hatcheries, the use of sophisticated partial-re-use water systems, rearing areas, holding tanks, effluent treatment systems, etc. They also have scientific staff who are quite knowledgeable about IPNV, some of whom have published papers in the scientific literature.
The CRSPP situation, however, may be unique to them, in that the historic hatchery’s design is so much a departure from that which is usually encountered. Preservation of this hatchery will be intimately associated with getting the viral titers in the entire watershed down to acceptable levels for rearing fry.
It is unclear at this time whether “conservative” measures involving reducing the trout population will suffice to reduce viral loads, especially in view of the invertebrate (amphipod) biomass of the river. Furthermore, it has already been pointed out that adding a pumped-water hatchery volume to existing river flows would overwhelm the stream’s carrying capacity.
Lastly, it should be noted that FWI is institutionally biased in favor of sustaining wild fish populations and against hatchery transplants
Their original proposal suggested they could start their work by May or June, 2009 but because of financial difficulties in OPR, a late-September start, at the earliest, is contemplated—and that would be only for the most preliminary suggestions. The projected cost of actually instituting those suggestions could very well be prohibitive at this time, if ever.
A DANGER TO OTHER WATERSHEDS?
Both NYSDEC and the local chapters of Trout Unlimited, a national coldwater fisheries conservation organization, have expressed great concern that the presence of IPNV represents a grave threat to presently uncontaminated watersheds on Long Island. T.U. is worried that virally-infected fish from CRSPP may make their way to other L.I. waters via the Connetquot estuary. In addition, there could be inadvertent spread via contaminated fishing equipment, and of course, the influence of avian vectors, most notably osprey & waterfowl.
Actual historical evidence, however, would suggest that those fears, while reasonable, may be a bit misplaced. We know for a fact that no IPN existed @ CRSPP in 1975, because in that year the Cold Spring Harbor fish hatchery, shut because of some disease, was re-stocked with Connetquot trout, and has remained disease-free since.
It is likely that the CRSPP contamination occurred in 1980, because hatchery records reflect that year to have been one of particularly high fry mortality .Disease was not suspected at that time, but no good alternative explanation other than unusual water temperatures could be found. Remember that IPNV acts as a “point source” epidemic. This unexpectedly high fry mortality is in perfect concordance with a point-source outbreak. And, since the disease rapidly becomes endemic and mortalities thereafter are not consistently in the 50-80% range, this scenario makes perfect sense.
The CRSPP hatchery had never been tested for anything other than Myxobolus cerebralis, or so-called “Whirling Disease” from 1980 until 2006.
Thus, for a likely 26 years, fishermen with felt-soled boots had constant access to the Connetquot and subsequently to other rivers such as the Carmans & Nissequogue, not to mention the storied up-state Catskill and Adirondak rivers. And during this time, Connetquot trout were regularly used to stock the Nissequogue at Caleb Smith State Park. Connetquot trout were regularly “going to sea” as well, and untold thousands of migratory waterfowl were seasonal visitors as well as resident to its waters --- And yet, no other Long Island watershed has been infected., as far as NYSDEC can determine.
It has also been shown, experimentally, that the intentional introduction of a virally-carrying trout into a ‘clean’ stream does not suffice to horizontally infect the other resident trout, owing to the dilutional effect of flow volumes. Nor does the literature cite any proven, controlled study quantifying the infection threat posed by one or more raptors or waterfowl. That is not to say it does not exist, but rather that the imported viral ‘load’ has not been quantified vis-à-vis any given watershed’s water debits.