Eculypt in creeks for fish

weirmeister · 21st November 2011, 05:42 AM

Hello, This is my 1st post. I'm a stream restoration contractor living and working in northern California. The focus of my work is to enhance in- stream rearing habitat for coho salmon and steelhead trout. I do this with Redwood, Fir and Bay Laurel logs and root wads.

I have proposed to CA Fish and Game the use of Eucalptus in my work. They want me to prove to them that the oils in the bark and trunk are not toxic to aquatic ecosystem. And I want to know for myself as well, I don't want kill the very fish and critters I"m helping.

The main reason I want to use Eucs is the cost, I just have to pay for trucking to get them to the sites.

Any feed back/ experience would be appreciated.

Doug

Eric Frei · 21st November 2011, 08:21 AM

Well, it is not as though tons of fish a dying in Australia's river systems from gum trees.

But, that doesn't mean it is safe for your rivers. There would be influencing factors too, like ppm of natural substances in the water depends on flow rates and volume of debris. If the logs were dried out totally then it would be different too perhaps, but I would be inclined to say it would logically be safer to use what is natural to the area as the ecosystem evolved with that and you are not introducing a new unknown.

Some excellent links:-

Plants Poisonous to Livestock - Cornell University Department of Animal Science

http://sun.ars-grin.gov:8080/npgspub...uest=Go&amt=sc

There's some research here, and you likely need to dig around for scientific papers.

http://www.google.com.au/url?sa=t&rc...jAHj4A&cad=rja

Quote:

The habitat 'value' of logs on floodplains is a composite of the contribution to
biodiversity during the dry phase and the wet phase. The faunal assemblage using logs
as habitat during flooding was very different to the terrestrial fauna. However, the
diversity of aquatic taxa on river red gum logs immersed in floodwaters also was low,
with a mean of 3.6 ± 0.7 species per log 6 wk after inundation commenced. In flowing
streams, after colonization for 8 wk, O'Connor (1991) recorded species richness of
invertebrates on similar-sized river red gum logs an order of magnitude greater than in
the current study. In the current study, the floodwater covering the logs was fairly
stagnant and dark brown, indicating high levels of phenolic compounds. Gehrke (1993)
demonstrated that river red gum leachates are toxic to juvenile fish. High
concentrations of dissolved phenolics and low oxygen levels in the floodwaters
probably restricted the number of invertebrate taxa able to colonize the submerged logs.
Therefore, the low diversity of the log fauna during both the wet and dry phase probably
is a result of the combined effects of environmental conditions and the chemistry of
river red gum.

Some more:-

Effects of river red gum, Eucalyptus camaldulensis, litter on golden perch, Macquaria ambigua - Gehrke - 2005 - Journal of Fish Biology - Wiley Online Library

Quote:

Aquaria with added river red gum, Eucalyptus camaldulensis, litter became hypoxic, with decreased pH and contained up to 30 mg 1−1 tannin and lignin. Survival of golden perch, Macquaria ambigua, larvae in aquaria treated with a simulated annual litter density of 450 g m−2 for 72 h was 14·9% for 15-day-old larvae and 0% for 8-day-old larvae. A litter density of 1223 g m−2 resulted in total mortality for both age groups of larvae. Aeration increased survival of larvae to a minimum of 68·8% in 1223 g m−2 litter treatments compared to 89·8% in aerated controls and 86·8% in non-aerated controls. A kinetic behavioural assay was used to detect alarm responses in golden perch larvae and juveniles exposed to leachates from river red gum bark, leaves and wood. Eight-day-old larvae exposed to bark and wood leachates (0·001–10 g 1−1) exhibited an initial period of hyperactivity, followed by a concentration-dependent decrease in spontaneous activity. Larvae exposed to leaf leachates displayed only a decrease in spontaneous activity. Four-month-old juveniles exposed to wood leachates were also initially hyperactive, then progressively developed mild hypoactivity at increasing leachate concentrations. Juveniles exposed to wood leachates at 20g 1−1 for 30min suffered 97·5% mortality in 96 h. Wood leachates induced dose-dependent lamellar fusion, epithelial dissociation and necrosis in the gills. The presence of toxic leachates and low oxygen availability in flooded river red gum forests may make these habitats unsuitable as nursery areas for native fish.

21st November 2011, 05:42 AM	#1
weirmeister I'm new here so be nice Join Date: Nov 2011 Location: Sebastopol California Posts: 1	Eculypt in creeks for fish Hello, This is my 1st post. I'm a stream restoration contractor living and working in northern California. The focus of my work is to enhance in- stream rearing habitat for coho salmon and steelhead trout. I do this with Redwood, Fir and Bay Laurel logs and root wads. I have proposed to CA Fish and Game the use of Eucalptus in my work. They want me to prove to them that the oils in the bark and trunk are not toxic to aquatic ecosystem. And I want to know for myself as well, I don't want kill the very fish and critters I"m helping. The main reason I want to use Eucs is the cost, I just have to pay for trucking to get them to the sites. Any feed back/ experience would be appreciated. Doug

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