Didymosphenia geminata(didymo)

in the West Branch Farmington River:An Introduction & Update

Mike.Beauchene@ct.gov

CT DEP

presentation to the Northwest CT chapter T.U.

May 3rd 2011

What is it?

• Didymosphenia geminata or “Rock Snot”• Algae

• Belongs to a family of diatoms (many species)

• Some are native to CT– Cymbella spp., Gomphoneis spp., Gomphonema spp

• Microscopic single cell diatom

– Each cell produces a stalk

– Stalks are resistant to decomposition

• Groups of many stalks combined can form

significant algal mats and these mats are

what elevates anxiety.

How do you tell if it is didymo?

• Requires microscopic verification– cell structure is unique

– other species look similar

• Tufts, Blobs, Mats, or Clumps

• White, yellow, or brown in color

• Not slippery or slimy more coarse

• When pulling apart it offers

resistance similar to a wet cotton ball

or wet wool

Where does it come from?

• Native species

– Northern latitudes of Europe, Asia & North America

• Problem Blooms• New Zealand

• Canada (Southern Quebec, British Columbia)

• United States

– Several western States (SD, WY, MN,CO, CA, WA, AK)

– Mid Atlantic States (PA, WV, TN, VA, NC)

– Arkansas

– Northeastern states (VT, NY, NH, CT)

Where is didymo?

• New Zealand

• Canada (Southern Quebec, British Columbia)

• United States

– Several western States (SD, WY, MN,CO, CA, WA, AK)

– Mid Atlantic States (PA, WV, TN, VA, NC)

– Arkansas

– Northeastern states

• Vermont

• New York

• New Hampshire

• Connecticut (West Branch Farmington River)

Didymo present in Canada in the late 1800s, but did

not begin to cause problems until the early 1990s.

It was present in the rivers of the Western U.S. by

2004, and it was first discovered east of the Mississippi

River in 2005 in Tennessee.

What does it like?(Miller and others 2009)

• Cold water temperature

• Low levels of nutrients

– Nitrogen

– Phosphorous especially organic phosphate

• Stable flow regime

• Shallow

• Rocky substrate

• Tail-water areas

– Meet most of the above conditions

How does it move around?

• Slide around with a foot-like structure (raphe)

• Planktonic drifter

– Single cell floats downstream

– Stick to waders and such

• Clumps

– Sloughing off and drifting downstream

– Stuck on waders, canoes, nets, etc..

How can you disinfect after a didymo exposure?

• Very hot water > 140 F**, soak 1 minute for hard items, 40 minutes for absorbent items **note this is warmer than most tap water.

• 2% bleach solution

• 5% solution of dishwashing detergent for hard items, soak for 30 minutes for absorbent items

• Freezing solid

• Drying completely

Why all the fuss?

• New Zealand’s lead

– Tremendous biomass

–Very prolific mats formed

– hypothesis these mats will be destructive to the biota

– Smother and destroy invertebrate community

– Starve fish community due to lack of food

Is the sky falling?

• New Zealand

– Leader world wide in research to date

–U.S. introductions very recent and publications are starting to appear

• Hypothesis these mats are destructive to the biota

– Invertebrate community

– Fish community

Is the sky falling?• Now that it is here we are not seeing the

same result!!

• Hypothesis these mats are destructive to the biota is not supported.

– Invertebrate community

• Community change but not numbers or total types

– Fish community

• Less studies have been done

• Smaller fish do much better

– Angling opportunities

• Decrease in aesthetics

• More difficulty “nymphing”

Key findings to dateInvertebrates

• Studies agree there is no adverse effect!!

– Community structure does

• shift from a mayfly, stonefly, caddisfly dominated system to one dominated by midges.

• Total abundance increases or stays the same

• Total species present increases

• Total density of mayfly and stonefly tend to increase

• Density of caddisfly tend to decrease

• Shift from larger bodied insects to smaller bodied insects, but you get a lot more of them.

Key findings to date• Fish

• Fewer studies than invertebrates

• Again most papers agree no adverse effect!!

– Younger and smaller sized trout

• Greater quantities

• Higher biomass

– Adults and older fish

• Jury is still out

• More research ongoing

Case Study: Vermont(State DEC presentation & Degree project)

• Macroinvertebrate community shift per other findings– Collector-filterers decrease

– Collector-gatherers increase

– Overall community scores for water quality increase slightly

– Resembles an invertebrate community found in a stream characterized with high nutrient loads.

– Could not confirm a negative impact

– The presence of high percent cover of D. geminata did not have major impacts on the density or diversity of macroinvertebrates.

• Fish work ongoing

Case Study: South Dakota

• “growth of brown trout would not be negatively affected by D. geminata even though taxonomic differences and changes in the size and structure of invertebrates were observed at sites which it was present. We observed a marked increase in the relative weight of the brown trout…which could be explained by density-dependant factors, increased invertebrate abundance associated with D. geminata, or both” (James et al 2010).

Case Study: Quebec(Gillis and Chalifour 2009)

• Macroinvertebrate community

– Overall community scores were not different

– Density increased by 4 times

– Proportion of mayflies, stoneflies, caddisflies decreased with D. geminata

– Shift to midge dominance

• Fish community not assessed

– Proposed question that a shift in inverts could cause trophic problems?

Case Study: New Zealand

• A review of information on the impacts of didymo on trout indicates that there is currently no scientific evidence available demonstrating the negative effects on trout population parameters (abundance and growth) Moreover, there is no scientific evidence available from anglers on the effects of didymo on trout catch rate and size.

Case Study: New Zealand (cont.)

The negative impacts on trout and salmon fishing, indicated from anecdotal reports from anglers, are aesthetic, fouling of fishing lures, and the inconvenience of having to clean fishing gear and boots.

Where are we now?• Public education and awareness phase

– Expansion of guidance and recommendations

– Provide honest and objective information

– Dispute and correct mis-perception and mis-information

• Objectively evaluate the condition and monitor for effect and change so to understand the issue.

• Observe and document one day at a time with an eye for the future.

• Be aware that a cure may be worse than the disease!

• Is it really that bad or just a new reality?

• Try to prevent transfer to other waterbodies

– Risk assessment of waters within the state

Stay tuned - more info from CT DEP and collaborators

EDUCATION is the key!

The Law: currently there are no laws in CT that specifically address didymo; however.....

CGS Sec. 15-180. Transporting vessel or trailer without inspecting for and properly removing and disposing of vegetation. Penalty.

(a) No person shall transport a vessel, as defined in section 15-127, or any trailer used to transport such vessel, in the state without first inspecting such vessel for the presence of vegetation and properly removing and disposing of any such vegetation from such vessel or trailer.

(b) Any person who violates the provisions of this section shall be fined not more than one hundred dollars for each such violation.

Education: Tri-fold didymo brochure developed by DEP

Part 2: Summary of initial survey conducted 3/25/2011

West Branch Timeline• Public post didimo in West Branch Farmington River on chat thread

(3/18/2011)

• Public reads chat tread and emails to Neal Hagstrom & Mike Beauchene with link to web postings and request to check it out (3/18-3/21/2011)

• To reduce prior storage from large precipitation events pre-planned MDC releases begin. Approximately 1800 CFS for 3 day period immediately following reported observation (3/18/2011-3/21/2011)

• Sample collected by Robert Carpenter and brought to CT DEP (3/21/2011).

• WPLR initial review could not rule didimo out and recommends to Inland Fisheries to have an expert, State of Vermont, review the sample (3/23/2011)

• Mike Beauchene conducts a simple survey to get a handle on the conditions in the West Branch Farmington River, Barkhamsted (3/25/2011)

• State of Vermont verified sample to be didimo (3/25/2011)

Stop1

Stop2

Stop3

Stop4

Stop5 &6

Stop7

Stop8

Stop9

Locations of visual survey 3/25/2011

West Branch Farmington River

• Present from Route 20 in Riverton south to lowest extent surveyed(between Pleasant Valley and New Hartford)

• Isolated and sporadic clumps in lower part of river

• More numerous and larger clumps in upper river

West Branch Farmington River

Appears to be in initial colonization phase as of 4/2011

Hard to find if not looking for it, not very abundant

Could not evaluate more preferred riffle habitats due to high flows 3/23/2011

dried didymo shown with other materials after high water receded

Summary

• Didymo confirmed in West Branch Farmington River

• Stalked diatom with potential for producing massive mats.

• Other New England states are not seeing adverse ecological impact.

• Educate public with objective and accurate scientific-based information.

We encourage all to continue enjoying the unique ecological and recreational opportunities the West Branch Farmington River provides!!!

Resources

• CT DEP Inland Fisheries 860-424-3474

• CT DEP web page (www.ct.gov)

• Biosecurity New Zealand (http://www.biosecurity.govt.nz/didymo)

• VT DEC

http://www.anr.state.vt.us/dec/waterq/lakes/htm/ans/lp_didymo.htm

Citations & Bibliography• 1) Kilroy, C. (2004). A new alien diatom, Didymosphenia geminata (Lyngbye) Schmidt: its biology, distribution, effects and potential risk

for New Zealand fresh waters. NIWA Client Report: CHC2004-128 prepared for MAF Biosecurity New Zealand. NIWA Project: ENS05501. 40pp.2) Kilroy, C et al. (2006). Ecological studies on Didymosphenia geminata. NIWA Client Report: CHC2005-123 prepared for MAF Biosecurity New Zealand. NIWA Project: MAF05505. 79 pp.3) Larned, S et al. (2007). Ecological studies of Didymosphenia geminata in New Zealand, 2006-2007. NIWA Client Report: CHC2007-070 prepared for MAF Biosecurity New Zealand. WA Project: MAF07507. 140 pp.4) Hayes, J. W., Shearer, K. A. and Hay, J. (2006). Invertebrate drift and trout growth potential in a Didymo (Didymosphenia geminata) affected reach of the Mararoa River. Prepared for Biosecurity New Zealand. Cawthron Report No. 1178. 43 pp.5) Shearer, K. A., Hay, J. and Hayes, J. W. (2007). Invertebrate drift and trout growth potential in Didymo (Didymosphenia geminata) affected reaches of the Mararoa and Oreti rivers: April and August 2006. Prepared for MAF Biosecurity New Zealand. Cawthron Report No 1214. 83 pp.6) Hayes, J.W. and Jowett, I. G. (1994). Microhabitat models of large drift-feeding brown trout in three New Zealand rivers. North American Journal of fisheries Management, 14, 710-725.7) Hayes, J. W., Stark, J. D. and Shearer, K. A. (2000). Developments and test of a whole-lifetime foraging and bioenergetics growth model for drift-feeding brown trout. Transactions of the American Fisheries Society, 129, 315-332.8) Spaulding, S. and Elwell, L (2007) Increase in nuisance blooms and geographic expansion of the freshwater diatom Didymospheniageminata: Recommendations for response. Environmental Protection Agency and Federation of Fly Fishers Montana. 33pp.9) Gillis, C-A. & Chalifour, M. (2010). Changes in the macrobenthic community structure following the introduction of the invasive algae Didymosphenia geminata in the Matapedia River (Quebec, Canada). Hydrobiologia, 647, 63-70.10) James, D. A. et al. (2010). Invertebrate composition and abundance associated with Didymosphenia geminata in a montane stream. Journal of Freshwater Ecology, 25(2), 235-241.11) Shelby, E. L. (2006). An assessment and analysis of benthic macroinvertebrate communities associated with the appearence of Didymosphenia geminata in the White river below Bull Shoals Dam. Report of findings for Arkansas Dept. of Environmental Quality Water Planning Division. 42 pp.12) Clearwater et al. (2007). Didymosphenia geminata experimental control trials: Stage three phase one (assessment of the effectiveness of GemexTM, a chelated copper formulation, in a small river. NIWA client report: HAM2007-060 for MAF Biosecurity New Zealand. NIWA Project: MAF0720

• 13. HTTP://TURNINGOVERSMALLSTONES.BLOGSPOT.COM/2011/01/DIDYMOSPHENIA-GEMINATA.HTML FRIDAY, JANUARY 21, 2011

What are your questions?

Contact:Inland Fisheries Division

Connecticut Department of

Environmental Protection

79 Elm Street

Hartford, CT 06106

860-424-3474

peter.aarrestad@ct.gov

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