Just wanna discuss nitrates

[philipraposo1982]

Evidence suggests that sensitivity to nitrate is species-specific. Kincheloe et al. (1979) reported larval mortality of Chinook salmon, rainbow trout, and cutthroat trout at concentrations as low as 2.3-7.6 mg/L NO3-N. The 96-hr LC50 (median lethal concentration) for fathead minnow larvae is 1,341 mg/L NO3-N (Scott and Crunkilton 2000), and the lethal dose for adult and juvenile medaka is 100 mg/L NO3-N (Shimura et al. 2002).

A range of sublethal effects of nitrate has also been reported. For example, Greenlee et al. (2004) observed increased apoptosis and reduced cell number in cultured preimplantation mouse embryos exposed to 1 mg/L ammonium nitrate. In an accumulated nitrate test, in which nitrate built up over the course the experiment, Shimura et al. (2002) observed delayed hatching time and reduced fertilization and hatching rates of eggs produced by adult medaka exposed for 2 months to a maximum of 75 mg/L NO3-N. In that test, the offspring also exhibited reduced juvenile growth rates. At 50 mg/L NO3-N, Shimura et al. (2002) observed reduced spawning and fecundity (measured as egg number) among adult medaka exposed to nitrate as juveniles.

Just one example.

 

[philipraposo1982]

6. Concluding remarks It should be evident, from data presented in this review, that nitrate discharges from anthropogenic sources may result in a serious ecological risk for certain aquatic animals. Indeed, as a consequence of nitrogen pollution, nitrate concentrations in surface waters can actually exceed values of 25 mg NO3-N/l (Bogardi et al., 1991; Gleick, 1993; Ministry of Agriculture, Fisheries and Food, 1993). Because a nitrate concentration of 10 mg NO3- N/l (USA federal maximum level for drinking water) can adversely affect, at least during long-term exposures, freshwater invertebrates (Eulimnogammarus toletanus, Echinogammarus echinosetosus, Cheumatopsyche pettiti, Hydropsyche occidentalis), fishes (Oncorhynchus mykiss, Oncorhynchus tshawytscha, Salmo clarki), and amphibians (Pseudacris triseriata, Rana pipiens, Rana temporaria, Bufo bufo) (Tables 1–4), safe levels below this nitrate concentration are therefore recommended to protect these sensitive freshwater animals from nitrate pollution. Furthermore, following Kincheloe et al.s (1979) recommendation, we consider that a maximum level of 2.0 mg NO3-N/l would be appropriate for protecting the most sensitive freshwater species. In the case of marine invertebrates and fishes, we consider that the proposed maximum level of 20 mg NO3-N/l for culturing seawater animals (Spotte, 1979) may in general be acceptable. However, early developmental stages of some marine invertebrates (Muir et al., 1991), that are well adapted to low nitrate concentrations, may be so susceptible to nitrate as sensitive freshwater invertebrates (Tables 1 and 2).

http://www.waterboards.ca.gov/water_issues/programs/tmdl/records/region_2/2008/ref2426.pdf

 

[Woefulrelic]

i agree, there simply isnt enough data to get a conclusive understanding. But i believe that works both ways... if there isnt enough data to prove that a ray's life expectancy isn't affected by nitrates, then there isnt enough data to prove that nitrates <40 would give a longer life expectancy.

that aside, while i readily acknowledge i cant give the answer for long term effects (10-20 year++?), i can say that 1xx nitrates do not mean your fish will end up sick or dead in months, years. that i can definately prove. so i really want to hear from those who think otherwise, about their first hand experiences, or what made them believe thus, apart from reading literature.

and apart from comparing natural levels of nitrates and attempting to assimilate them, how was it established that X level is safe Y level is not Z level makes fish sick/die? ammonia u get direct "burns", nitrites u get blood "toxification", so what about nitrates? most case studies that i've seen that actually could provide cold hard data was in relation to food fishes, not ornamental fish.

it's an open discussion. i would really love to hear more personal experiences on how nitrates directly affected one's fishes, be it short term or long term. i'm throwing out my experience here in the hope of being proven wrong, i'm not debating because i want to be right, i want to know why i'm wrong in a manner i can believe in.

I'm not trying to disagree with you, but here my bone with the argument.

I have no idea how long these rays are supposed to live in the wild, or captivity. What if aquarium side fish don't make it much past 20 yrs but wild rays love 40 or more. Afaik we haven't been keeping rays long enough to have a strong consensus on their life expectancy in home setting. The data we have at our hands is too weak to make any assertions. For tobacco it effects humans and a much higher population % have smoked than kept rays. There's just not much demand for this kind of research and the scale required keeps it far from the hands of us hobbyists.

I don't disagree with you though. I look at them as a constant battle and try to keep them as low as feasible.

 

[Dieselhybrid]

With Rays being such eating machines, and with their primitive stomach, and the fact they produce such massive amounts of ammonia, it's really hard to keep nitrates below 50 without a drip. we usually do 1 or 2 80-90% water changes weekly on systems without drips. This drops nitrates to 10 after water changes but even in our 720 gallon ponds the nitrates are at 50+ again within 2 days of water change with the heavy feeding and messy rays.

The tanks and ponds with drip systems are much easier to regulate but still require around a 10-15% change daily to maintain low enough nitrates that they don't begin to creep up faster than the drip eliminates them.

 

[RayJunkie]

6. Concluding remarks It should be evident, from data presented in this review, that nitrate discharges from anthropogenic sources may result in a serious ecological risk for certain aquatic animals. Indeed, as a consequence of nitrogen pollution, nitrate concentrations in surface waters can actually exceed values of 25 mg NO3-N/l (Bogardi et al., 1991; Gleick, 1993; Ministry of Agriculture, Fisheries and Food, 1993). Because a nitrate concentration of 10 mg NO3- N/l (USA federal maximum level for drinking water) can adversely affect, at least during long-term exposures, freshwater invertebrates (Eulimnogammarus toletanus, Echinogammarus echinosetosus, Cheumatopsyche pettiti, Hydropsyche occidentalis), fishes (Oncorhynchus mykiss, Oncorhynchus tshawytscha, Salmo clarki), and amphibians (Pseudacris triseriata, Rana pipiens, Rana temporaria, Bufo bufo) (Tables 1–4), safe levels below this nitrate concentration are therefore recommended to protect these sensitive freshwater animals from nitrate pollution. Furthermore, following Kincheloe et al.s (1979) recommendation, we consider that a maximum level of 2.0 mg NO3-N/l would be appropriate for protecting the most sensitive freshwater species. In the case of marine invertebrates and fishes, we consider that the proposed maximum level of 20 mg NO3-N/l for culturing seawater animals (Spotte, 1979) may in general be acceptable. However, early developmental stages of some marine invertebrates (Muir et al., 1991), that are well adapted to low nitrate concentrations, may be so susceptible to nitrate as sensitive freshwater invertebrates (Tables 1 and 2).

http://www.waterboards.ca.gov/water_issues/programs/tmdl/records/region_2/2008/ref2426.pdf

thanks for the links!

The main toxic action of nitrate on aquatic animals is due to the conversion of oxygen-carrying pigments (e.g., hemoglobin, hemocyanin) to forms that are incapable of carrying oxygen (e.g., methemoglobin) (Grabda et al., 1974; Conrad, 1990; Jensen, 1996; Scott and Crunkilton, 2000; Cheng and Chen, 2002). Nevertheless, owing to the low branchial permeability to nitrate, the NO 3 uptake in aquatic animals seems to be more limited than the uptake of NHþ 4 and NO 2 , contributing to the relatively low toxicity of nitrate

so apparantly effects of nitrates are the same of nitrites, but due to lower permeability nitrates are a lot less toxic. Same problem as usual though, no exact figure can be given for what level of nitrates is too high.

One point to take note was the case studies were mostly centered on food / aquaculture fish like salmon / rainbow trout. and the studies were done on fry or fingerlings, without any tests done on juveniles or adults. So while interesting i wouldnt say it's all that applicable.

Interestingly enough though :

the noobserved-effect concentration (NOEC) and the lowestobserved-effect concentration (LOEC), for the growth of newly hatched larvae (<24 h old) of P. promelas after an exposure of 7 days, were 358 and 717 mg NO3-N/l

which proves that for some fish species, even the most sensitive larvae stage are fine with 300+ nitrates and start suffering side effects at 700+ nitrates.

Also of interest is :

Knepp and Arkin (1973) reported that the channel catfish Ictalurus punctatus was able to tolerate a nitrate concentration of 90 mg NO3-N/l without affecting their growth and feeding activity after an exposure of 164 days

And other cases where certain species could tolerate 1000+ nitrates with no ill effects, although the duration of the test was 96 hours.


Whilst there's still no proper answer to our focus on rays, at least it's clear that some fish are way more tolerant of nitrates than others, n anything higher than 40+ kills/damages is not true except for the most sensitive. Clearly rays are not one of the most sensitive to nitrates.

 

[RayJunkie]

I'm not trying to disagree with you, but here my bone with the argument.

I have no idea how long these rays are supposed to live in the wild, or captivity. What if aquarium side fish don't make it much past 20 yrs but wild rays love 40 or more. Afaik we haven't been keeping rays long enough to have a strong consensus on their life expectancy in home setting. The data we have at our hands is too weak to make any assertions. For tobacco it effects humans and a much higher population % have smoked than kept rays. There's just not much demand for this kind of research and the scale required keeps it far from the hands of us hobbyists.

I don't disagree with you though. I look at them as a constant battle and try to keep them as low as feasible.

By all means do disagree. the whole point of this thread is to disagree or there won't be any debate.

i get your point, we have no idea how long the natural life span of a ray in captivity is, so we can only speculate, whether be it erring on the side of caution, or testing the limit. On another note, if it isn't rays specifically, i know ppl with gars/aros/snakeheads etc that have had their fish for over a decade, some even two decades. They do not test for nitrates, but judging from their bioload and the almost non-existent water changes they do, i'm pretty sure it's permanently in the 3 digits. Although the natural lifespan of those fish span more than just 2 decades, at least it's a guage that they can still survive for at least that long.

i try to keep my nitrates as low as possible too, sadly my tapwater isn't forgiving enough.

 

[RayJunkie]

Do you do manual water changes on your ray tanks, or run constant drip?

Manual water changes. i screwed up when i moved house, and did not plan for a drip system beforehand. impossible to get it done now without drilling holes in the walls/doors and my wife is not exactly receptive to that idea.

will be moving again in 2 years time, will be able to upgrade tank sizes dramatically and get a proper irrigation system done then.

 

[RayJunkie]

With Rays being such eating machines, and with their primitive stomach, and the fact they produce such massive amounts of ammonia, it's really hard to keep nitrates below 50 without a drip. we usually do 1 or 2 80-90% water changes weekly on systems without drips. This drops nitrates to 10 after water changes but even in our 720 gallon ponds the nitrates are at 50+ again within 2 days of water change with the heavy feeding and messy rays.

The tanks and ponds with drip systems are much easier to regulate but still require around a 10-15% change daily to maintain low enough nitrates that they don't begin to creep up faster than the drip eliminates them.

i do 2 x 50-80% water changes weekly and still end up with 100+. lowest i ever got right after a 90% wc including flushing the sumps was around 50-60.....

i'm not even sure how much more beneficial a 24/7 drip would be in my case cause of the high chloramine content... by the time i get the water pass the carbon filters and get the chloramine stripped down to ammonia... the ammonia will still end up as nitrates.... unless i run zeolite or something at the last stage.

 

[philipraposo1982]

I am curious, is the nitrates only an issue at the younger age of the rays because you folks tend to feed a lot and often to ensure good growth and development? or is the kind of feeding habit the whole life of the ray?

My thought that if as adults you can go to a single feeding it would likely be easier to control nitrates.

 

[RayJunkie]

I am curious, is the nitrates only an issue at the younger age of the rays because you folks tend to feed a lot and often to ensure good growth and development? or is the kind of feeding habit the whole life of the ray?

My thought that if as adults you can go to a single feeding it would likely be easier to control nitrates.

i feed 4 x daily for smaller rays, 2 x for adults. but the amount of food the adults take n the amount of poop is many times crazier than the smaller ones. i should cut down to once a day tbh but i think i've spoilt them since young so they're like 24/7 hungry. Plus i shifted to 80% pellet diet and that really makes the poop a lot worse lol,