Imazamox and the Elimination of Japanese eelgrass Habitat Funtions

Reminder:  Comments are still being accepted through March 9 on the shellfish industry's request to eliminate Japanese eelgrass from commercial shellfish beds through application of the herbicide Imazamox in Puget Sound and the state's marine waters.  This is only one more example of the shellfish industry's desire to transform Puget Sound's habitat. (see Feb 18 post for background on how shellfish lobbying put Imazamox on the "noxious weed" list)

Comments should be sent to:  Kathy.Hamel@ecy.wa.gov with "Stop Imazamox" in the subject line.

Following is what tideland habitat biologist Dan Pentilla has to say about the shellfish industry's proposed eradication of this important habitat species using the herbicide Imazamox in Puget Sound.  Dan Pentilla worked for the Washington Deparment of Fish and Wildlife for 39 years, much of it spent researching and documenting forage fish habitat. 

This was what he sent to the Department of Ecology:

SUBJECT: Zostera japonica as documented herring spawning habitat in Grays Harbor and Willapa Bay
I wish to comment from my personal observations of the usage of “japanese eelgrass” as herring spawning substrate in Washington’s coastal estuaries. I am a recently retired WDFW forage fish biologist, having spent 39 years involved in investigations of herring, surf smelt, and Pacific sand lance biology, spawning ecology and critical spawning habitat mapping throughout the state of Washington. By way of record of my professional knowledge and experience, see: Penttila, D.E., 2007. The marine forage fishes of Puget Sound. PSNERP Tech Report 2007-03, at www.pugetsoundnearshore.org .
I have personally observed the usage of middle intertidal beds of Zostera japonica as egg-deposition substrate by Grays Harbor and Willapa Bay stocks of Pacific herring during their February-March spawning seasons. These records of my observations would be housed within the files and photo notebooks of the WDFW Marine Resources Division at their LaConner, WA office, if more specific details were needed. These records are considered public information, and I presume I would still have personal access to them, if requested. The degee to which extensive beds of Zostera japonica also serve as herring spawning habitat in the Salish Sea region, where herring spawning on adjacent beds of Z. marina overlaps with extensive aquaculture operations, such as Drayton Harbor (Whatcom Co.) and Samish Bay (Skagit Co.), should also be investigated before any industrial-scale applications of herbicides are allowed.
In southern Grays Harbor, I photographed as well as sampled herring eggs on Zostera japonica beds in the vicinity of the Bay City bridge over the Elk River estuary. In Willapa Bay, I recall herring eggs being found on Zostera japonica beds just inshore of the native Z. marina beds in the area north of Oysterville. In both areas, the herring spawning sites in question were within short distances of active shellfish aquaculture plots, and thus would be damaged or destroyed by the application of pest-control herbicides.
In my opinion, the herring spawning habitats of Grays Harbor and Willapa Bay already suffer enough damage from uncontrolled (ie. “voluntary codes of practice”) aquaculture activities annually, through the dredging of ground-cultured oysters during the spawning season, stomping and shading. They should not be further impacted by yet another ill-considered act for the benefit of the commercial aquaculture industry’s bottom line.
In these coastal estuaries, any attempted chemical control of Z. japonica beds immediately inshore and possibly intermingled with the inshore portions of Z.. marina beds would cause damage to the native Z. marina beds and their herring spawning habitat function. It is a poorly kept secret that the aquaculture industry has for generations considered eelgrass to be a “pest” and has routinely pursued measures to eradicate the species from their culture plots, despite the species’ clear ecological value.* Such damage to herring spawning habitats should be considered a violation of the WA State GMA, WA State SMA, the WAC Hydraulic Code Rules and federal Essential Fish Habitat rules for the conservation of ESA-listed salmonids in this region, all of which advocate no-net-loss protections for documented herring spawning grounds.
* Simenstad, C.A., and K.I. Fresh, 1995. Influence of intertidal aquaculture on benthic communities in Pacific Northwest estuaries: scales of disturbance. Estuaries, Vol 18, No. 1A, p. 43-70.
Thank you for this opportunity for input.
Dan Penttila
Salish Sea Biological (consulting on forage fish matters)