Gill Lice in PA Brook Trout

Growing up in Northcentral Pennsylvania, chasing wild brook trout has always been a passion for me.  I am always amazed when I read books such as The Vanishing Trout (Lose 1931) or Bodines (Up De Graff 1879) which talk of catching 18 inch brookies from the main stems of the Loyalsock or Lycoming Creeks with little effort.  Lose even proposed to close all the tributaries of the Loyalsock and other larger streams to fishing, preserving them as nursery waters, when now this is about the only place one can find a healthy population of brook trout. 

I've wondered many times what it would have been like to fish these streams before the lumbering days and the aftermath of sediment laden warm waters it left in it's wake.  Recently, I've been blessed to have the opportunity to fish Navarino Island in Cape Horn, Chile.  Navarino is a relatively untouched environment with some of, if not the most, pristine water in the world.  It also holds many brook trout over 18 inches (admittedly wild but not native).   While I am thankful for the chance to fish this magical place, I find myself thinking even  more about the fishery we used to have here, that at one time would have rivaled a place I now travel 7,000 miles to fish. 

Navarino Brook Trout

While the lumber days took its toll on our native brook trout population, most of the headwater streams continue to hold decent populations of these speckled beauties, even if they are typically on the diminutive side of the ruler.  Despite what may seem like a strong foothold in the mountains, the struggle continues.  Warming temperatures, the invasion of the Wolly Adelgid which is destroying our hemlocks that shade many of these streams, development of all types, and drought have been tough on Salvelinus Fontinalis.  This year was especially brutal as it relates to water levels and temperatures.  There were many days when fishing was not even an option, as there literally was no water in some of the high mountain streams, or water that was well above temperature levels where fishing would be considered responsible. 

Well, it appears there is now another hurdle for the brook trout of Pennsylvania, gill lice.  Gill lice are a parasitic copepod (tiny crustacean) that attaches to the gills or other external areas of fish and can cause significant trauma.  This can affect the trout's ability to respire, cause immune system dysfunction, affect warm water tolerance, and ultimately cause death.  The gill lice were detected in several Centre County freestone streams and appear to have originated from a co-op nursery.  While all of the hatchery fish were destroyed, the gill lice have been observed in wild brook trout collected during stream survey work. 

Brook Trout with gill lice (Photo used with permission from PFBC)

PFBC is still trying to determine the full extent of the problem, but they are asking that anglers who catch brook trout check the gills for indications of gill lice.  If you catch a trout that shows the presence of gill lice, you are asked to record the information listed below and submit it to David Nihart from PFBC.  Additional information can be found in this news release from PATU.

The brook trout of Pennsylvania are fighters and have endured much, but I sometimes wonder how much more they will be able to overcome.  Hopefully this will not be as bad of a situation as it has the potential of becoming, but I have my reservations.  I would also like to take this opportunity to remind everyone to clean their gear between trips for not only the slim chance of transferring gill lice, but other invasive species we are currently dealing with. 

"It is hard to imagine these streams without their rightful owners, the brook trout."  (Charles Lose, The Vanishing Trout, 1931). 

Information to be submitted to PFBC:

*Stream name.
*Where the fish was caught (e.g. Strobes Road Bridge near Milltown).
*If possible, include a latitude and longitude of catch location.
*Date fish was caught.
*Photo of fish that shows possible gill lice.

Please send information via email or standard mail directly to:
David Nihart | Fisheries Biologist
Pennsylvania Fish & Boat Commission
Division of Fisheries Management | Coldwater Unit
450 Robinson Lane | Bellefonte, PA 16823
www.fishandboat.com | davnihart@pa.gov