The Missouri Department of Conservation and Didymosphenia geminata

aka – Didymo or “rock snot”

Presenter: Mark Van Patten

Fisheries Management Biologist

Missouri Department of Conservation

Didymosphenia geminataaka – Didymo or “rock snot”

• Didymo (rock snot) is an invasive microscopic alga that grows in long stalks which are resistant to decay.

• It forms thick mats that have negative impacts on streams and can make fishing impossible.

• Didymo is expanding its range and tolerance throughout the world.

• Currently, Didymo exists in 19 22 states and occurs as close as northern Arkansas.

Didymo in Arkansas

The brown color is due to fucoxanthin, a pigment contained in each cell, (although each cell also contains chlorophyll) and the white or translucent color is due to the stalks.

Didymosphenia geminata

• Colonial diatom• Cells divide• Attachment as gelatinous stalks• Massive plant• Cells (200-300 microns)• A cell cleaned in sulphuric acid

and showing the ornamentaion critical for identification

Below are both a cell and stalk of Didymo found in the gut content of Gammarus (Scud) which was living in the stalk portion of Didymo at the time of collection. Also present are cells of epiphytic diatoms that were attached to the Didymo stalks.

A Gammarus found in a colony of living Didymo

Microscopic colony of Didymo scraped from a rock in the Beaver tailrace, March 2006

The ability of Didymo to remain attached to the substrate by the basal portion of the stalks probably contributes to its continued presence and redevelopment after a flood type event and/or seasonal changes. (1)

Gomphonema with stalks and division similar to Didymo. The major difference is that the stalk material of Gomphonema is slippery and that of Didymo is cottony.

Where is it currently found?

Conditions most favorable to Didymo colonization

• High N/P ratio, low phosphorus (< 2 ug/L) in the water. • Bright sunlight• Low TSS (total suspended solids)• pH (7-9)• Generally cold waters from 4 to 27 C (2)• Stable water flow: “mean flow regime is associated with

bloom development, based on a significant negative relationship detected between D. geminata biomass and mean discharge” (3)

What are its negative effects?

• The damage caused by Didymo is largely from the stalks produced by each cell of the diatom colony which form large mats on streambeds, decreasing clarity and oxygen availability (especially at night). In some areas mats 20cm (6 inches) thick have been reported. (6)

• When Didymo is absent or in low numbers, diversity of invertebrates is increased .(6)

• Significant changes in the kinds of invertebrates were found in an excellent study by EcoAnalysts Inc. (12) in examining the effects of Didymo in the Kootenai River, Montana/Idaho– EPT’s declined (Ephemeroptera (mayflies), Plecoptera

(stoneflies), and Trichoptera (caddisflies)),– “mats were a haven for midges and worms” (12)

More negative effects

• Another study on the negative effects of Didymo was undertaken by Erica Shelby of the Arkansas Department of Environmental Quality (26). She found decreases in the biodiversity of invertebrates associated with populations of Didymo.

• “In New Zealand D. geminata has been correlated to increases of invertebrates that are indicators of poor stream health” (7).

• Canals used for irrigation and aquifers in California are scraped of Didymo. It also clogs grates in the water supply canal (2).

• The stalks create a very unsightly looking benthos on the stream and on the shore where they dry resembling toilet paper.

Effect on trout Trout have been adversely affected by the presence of Didymo.

John Bell - Fisheries Biologist AG&F 2007The relative weight of brown trout below Bull Shoals dam in November 2006 was the lowest that has ever been recorded. Relative weight for both brown and rainbow trout have been falling in Bull Shoals tailwater since 2004, which coincides with the appearance of the invasive algae, didymo. This decrease in relative weight has been documented in other trout waters around the world where didymo has occurred.

It is believed that blooms of didymo in upper Bull Shoals tailwater have had the predicted detrimental effect on trout forage and trout foraging. Didymo carpets the bottom of the river and makes it impossible for native macro invertebrates to colonize or survive. Further, trout cannot forage efficiently in didymo and get no nutritional value from ingesting it.

What is being done to control Didymo in the streams that are infected?

• Models: One approach is to develop models that may predict the distribution of Didymo based on a sorting of habitats by air temperature, base water flow, precipitation seasonality, and other parameters. The former two seem to be able to account for much of the variance (10).

• Addition of phosphorus (8)• Copper: In New Zealand, a copper compound Gemex@ is

being used to control the growth of Didymo. Final field trial results show the potential of reducing growth of Didymo in applications in New Zealand (13). Some juvenile trout mortality occurred. Further testing is needed.

What else is being done!!

• DNA testing (19)• Scouring (5)• Cleaning Equipment after fishing • Public awareness: Many states have developed awareness

programs through website, posters, and talks such as this to create a public awareness tuned to the prevention of spreading Didymo from one habitat to another. One of the main “culprits” in the spread of Didymo from one stream to another is felt sole waders.

In Missouri we need to:

• Survey likely locations of Didymo• Spread the word of the potential impact of a

Didymo “bloom” on the fisheries• Utilize posters and other forms of

information regarding the hazards of not cleaning fishing equipment

Hand outs

ButtonsStickers

Pocket Fliers

Help Stop Didymo Check and Clean or Dry

• Check -Remove all visible clumps of algae and plant material from fishing gear, waders, water shoes and sandals, canoes and kayaks and anything else that has been in the water.

Help Stop Didymo Check and Clean or Dry

• Clean your gear in a 2

percent household bleach solution (1/3 cup per gallon of water), 5 percent saltwater solution (1 cup per gallon of water) or dishwashing detergent. Scrub boats and other “hard” items thoroughly.

• Completely soak equipment, personal flotation devices and other “soft” material for at least 20 minutes.

• Use the Boot wash stations in the four state trout parks

Help Stop Didymo Check and Clean or Dry

• Dry -Allow any item that has been in contact with the water to completely dry; the item should be exposed to sunlight and left to dry for at least 48 hours.

• Do your part–don’t spread Didymo.

• Please remember to Check and Clean or Dry your fishing gear and waders when moving between waters.

3 CSR 10-6.415 Restricted ZonesPURPOSE: This amendment prohibits the use of porous-soled waders or

footwear incorporating or having attached a sole of felted, matted or woven fibrous material when fishing in the following managed trout waters.

(A) Barren Fork Creek - Shannon County

(B) Blue Springs Creek - Crawford County

(C) Crane Creek - Stone and Lawrence counties

(D) Current River - Dent, Texas and Shannon counties

(E) Dry Fork Creek - Crawford and Phelps counties

(F) Eleven Point River - Oregon County

(G) Hickory Creek - Newton County

(H) Lake Taneycomo - Taney County

Little Piney Creek - Phelps County

(J) Meramec River - Crawford and Phelps counties

(K) Mill Creek - Phelps County

(L) North Fork of White River - Ozark County

(M) Roubidoux Creek - Pulaski County

(N) Spring Creek - Phelps County

(O) Capps Creek - Barry and Newton counties

(P) Niangua River - Dallas and Laclede counties

(Q) Roaring River - Barry County

(R) Maramec Spring Park - Phelps County

(S) Montauk State Park - Dent County

(T) Roaring River State Park - Barry County

(U) Bennett Spring State Park - Dallas and Laclede counties

(V) Stone Mill Spring Branch - Pulaski County

QR Code

Questions?

Didymo it’s Snot a Joke!

References

1. Whitton B, Ellwood N, Kawecka B. Biology of the freshwater diatom Didymosphenia: a review. Hydrobiologia [serial online]. September 2009;630(1)

2. http://epa.gov/Region8/water/didymosphenia/White%20Paper%20Jan%202007.pdf Spaulding, S and L. Elwell (2007)

3. Kirkwood, A. E., S. Troina, L. J. Jackson, and E. McCcauley. 2007. Didymosphenia geminata in two Alberta headwater rivers: an emerging invasive species that challenges conventional views on algal bloom development. Canadian J. Fisheries and Aquatic Sciences 64:1703-1709.

4. Floeder S, Kilroy C. Didymosphenia geminata (Protista, Bacillariophyceae) invasion, resistance of native periphyton communities, and implications for dispersal and management. Biodiversity and Conservation [serial online]. December 2009;18(14)

5. Miller M, McKnight D, Cullis J, Greene A, Vietti K, Liptzin D. Factors controlling streambed coverage of Didymosphenia geminata in two regulated streams in the Colorado Front Range. Hydrobiologia [serial online]. September 2009;630(1)

6. http://ecosystem-preservation.suite101.com/article.cfm/didymo_freshwater_diatom7. http://wildlife.utah.gov/pdf/AIS_plans_2010/AIS_12bDidymo-Dan-final.pdf8. http://www.ncd-afs.org/Pages/59/RSTC%20State%20Rpt%202007.pdf 9. http://www.niwa.co.nz/news-and-publications/publications/all/abb/2006-19/copper 10. Sunil Kumar, Sarah A Spaulding, Thomas J Stohlgren, Karl A Hermann, Travis S Schmidt,

Loren L Bahls (2009) Potential habitat distribution for the freshwater diatom Didymosphenia geminata in the continental US. Frontiers in Ecology and the Environment: Vol. 7, No. 8, pp. 415-420.

11. Pitte, D. P, K. A. Lane, A. K. Hermann, S. A. Spaulding, B. P. Finney. 2009. Historical abundance and morphology of Didymosphenia species in Naknek Lake, Alaska. Acta Bot Croat 68:183-197.

References (continued)

12. www.amaab.org/images/1510_Lester_Effects_of_the_Nuisance_Diatom_Didymosphenia_Gemi ata.pdf

13. www.niwa.co.nz/news-and-publications/publications/all/abb/2007-25/didymo

14. www.hoaff.org/newsletters/NL2007-04.htm

15. www.asee-nc.org/Conferences/Spring08Meeting/Srping08Proceedings/pdf/set2/71.pdf

16. www.flyfishnewengland.com/didymos-study.htm

17.www.mucinex.com/

18. www.articles.baltimoresun.com/2009-12-17/sports/0912170014_1_didymo-trout-waters-fishing-gear

19. www.waikato.ac.nz/news/archive.shtml?article=627

21. www.coyotegulch.wordpress.com/2009/05/11/large-instream-flows-help-control-didymo

21. http://www.westdenvertu.org/snails.htm#cleaning

22. http://www.chrisdore.com/whattobring.htm

23. http://www.unclejacks.co.nz/1.htm

24. http://www.fs.fed.us/r4/resources/aquatic/literature/matthews_quat_disinfectants_didymo.pdf

25. http://www.unclejacks.co.nz/4.htm

26. Shelby, E. L. 2006. An Assessment and Analysis of BenthicMacroinvertebrate Commumities Assocoated with the Appearance of Didymosphenia geminata in the Whitw River Below Bull Shoals Dam. ADEQ Final Draft. 42 pages.