Thread by @scotthepditch

1. Life stage coupled with water chemistry influence #lakesturgeon sensitivity to #lampricides, our latest work (@OanyBee #wilkielab) in @conphysjournal.

Read the full article here: bit.ly/2T3qDqW

@LampreyControl @LaurierBiology @LaurierResearch @Lauriergrad

2. #Sealamprey population control is critical for maintaining #ecological integrity of the #GreatLakes, as one lamprey can kill up to 40lb of lake trout during its parasitic life-stage.

3. #Lampricides are applied by @LampreyControl as part of an intergrated #pest management program, to target the larval stage of the #lamprey, residing in rivers and tributaries of the #GreatLakes.

Read more here: glfc.org/what-is-at-ris…

4. The main lampricide used to control #sealamprey is TFM, which specifically targets the larval #lamprey, with minimal effects on other fishes.

5. Juvenile lake #sturgeon are more sensitive to TFM than other non-target fishes, but the reasons for that are unknown.

6. Our work in @consphys has shown that younger #sturgeon are more sensitive b/c they take up more TFM from the water than older sturgeon:

YOY = Young of the year (a.k.a. less than a year old)
1+ = Greater than one year in age

7. More TFM in the body leads to increased negative effects, so the fish may die if they are exposed to it long enough.

8. Work from @FishOceansCAN suggested that #sturgeon sensitivity to #lampricides is linked to water chemistry.

See the article here: bit.ly/2ZY4GLq

9. #Sturgeon mortality was higher in waters of high alkalinity. Was it due to alkalinity or is the water chemistry changing the #lampricide and thus increasing toxicity?

10. More TFM is needed in high alkalinity waters to make sure that all the larval #lamprey die.

Read a detailed article here: bit.ly/2Qzb5JX

11. Therefore, high alk waters change the chemistry of TFM, making it less toxic to the lamprey. @LampreyControl crews need to add more TFM to make sure no lamprey survive.

Read a detailed article here: bit.ly/2T0KTtp

12. #Sturgeon that are found in the high alkalinity waters are thus exposed to higher levels of TFM than those in low alkalinity waters.

13. Therefore, a combo of age and water chemistry affects the sensitivity of #lakesturgeon to #lampricide TFM:

Alkalinity represented as CaCO3
YOY = Young of the year (a.k.a. less than a year old)
1+ = Greater than one year in age

14. High uptake rates in young #sturgeon + higher exposure levels in high alkalinity waters = increased sensitivity.

15. Recommendations:

1. Treat #sturgeon streams later in the year, to allow sturgeon to grow over the summer: larger/older fish, lower TFM uptake rates, increased survival.

16. Recommendations:

2. Consider alternate #lampricide treatments for #sturgeon streams: lower #lampricide exposure over longer time may reduce effects on #sturgeon. FIN.