Conservation and management of fish stocks hinges on an accurate assessment of the life histories of fish, environmental factors affecting their behaviour and growth, and population stock structure. Scanning proton microprobe can be used to establish the correspondence between Sr variation and optically resolved annuli in arctic charr otoliths. Anadromous and non- migratory fish can be unambiguously distinguished based on Sr distribution in otoliths. Otoliths from non-migratory fish have flat Sr profiles. In otoliths from migratory charr, Sr levels are low in the primordium and the first several annuli; the transition to a marine environment is marked by a sudden increase in Sr and a distinctive oscillatory zonation in Sr concentrations. Quantitative analysis of Sr can be used to distinguish the geographic origin of the fish.

The image on the left shows a 2-D Sr X-ray map of an otolith from a spawning char. Low-Sr annuli, clearly seen on both lobes of the otolith, indicate a period of freshwater residence that may be related to spawning activity. The image below shows Zn and Sr scans superimposed on a reflected light optical image of an otolith. Zn is an important biologically mediated element (particularly during gamete production), it is also a significant component of many mineral deposits.  Our most recent work has shown that Zn also shows a systematic pattern of oscillations.  More importantly, this oscillatory Zn content can be linked to the Sr variation and known life-history events in tagged fish and used as a proxy for size and growth rate, nutrient availability and environmental conditions and maybe also reproductive viability.




                               The incorporation of trace elements in otoliths crosses the interface between the inorganic and organic environment.  The trace-element signature found in the otoliths from fish in Eden Lake is very similar to that found in carbonates in the surrounding rocks arguing strongly that these elements were originally derived from the surrounding rocks.   Carbonate minerals in rocks commonly luminesce and preserve a chemical record of their growth.  In this case the same appears to be true for otoliths.  To correctly interpret the zoning signals we will require knowledge of the environment surrounding the fish habitat (including the rock, mineral and water chemistry), the fish’s metabolism and behaviour as well as information on nutrient type and availability


                                          Primary and strategic mineral production remains a key part of the Canadian economy, it underpins many small communities, particularly in northern and rural Canada.  In such settings the mineral industry must coexist with other resources and resource based economies (e.g., commercial, sport and aboriginal subsistence fisheries).  Aqueous environments represent regions of significant element mobility and dispersal so fish at some point are likely to come in contact with acid mine effluents. The aragonitic makeup of the otolith, and the fact that it preserves an annular growth record, means that it can sensitively record such chemical variation in the environment.  In this image the absolute values of Mn, Zn and Sr are much higher than have been encountered in our other micro-PIXE analyses of otoliths from freshwater fish.  The exceptionally high level of Zn recorded in a single lake whitefish otolith is the most unusual; it is amongst the highest Zn concentrations that we have recorded in any otolith.  The most reasonable explanation for the high Zn content is that at an early stage in its life this fish came into contact with RATS effluence from the Sherridon tailings.    Oscillating Zn might suggest that it migrated to and from where it may have been spawned.  The bulk of its adult life was probably spent in the main lake.  New work done using LA-ICP-MS indicates we can determine many more elements even at very low (parts per billion) concentrations.


Friedrich, L. A. and Halden, N.M. (2010) Determining Exposure History of Northern Pike and Walleye to Tailings Effluence using Trace Metal Uptake in Otoliths. Environmental Science and Technology  (in press).

Halden, N. M. And Friedrich, L.A. (2008) Trace element distributions in fish otoliths: natural markers of life histories, environmental conditions and exposure to tailings effluence. Mineralogical Magazine 23 (2), 591-603.

Friedrich, L. A. and Halden, N.M. (2008) Alkali element uptake in otoliths: a link between the environment and otolith microchemistry. Environmental Science and Technology  42, 10, 3524-3518.

Riva-Rossi, C.,  Pascual, M.A.,  Babaluk, J.A. and Halden, N.M. (2007) Intra-populational Variation in Anadromy and Reproductive Lifespan in Santa Cruz River Rainbow Trout Journal of Fish Biology 70, 1780-1797.

Palace V.P., Halden, N.M., Yang, P.,Evans, R.E. and Sterling, G. (2007) Determining life histories of rainbow trout using laser ablation inductively coupled plasma mass spectrometry  (LA-ICP-MS) analysis of selenium in otoliths. Environmental Science and Technology. 41, 3679-3683.

Halden, N. M.,  Mathers, K, , Babaluk, J. A. and   Mejia, S.R. (2004) Cathodoluminescence Microscopy: a useful tool for assessing incremental chemical variation in otoliths.  Environmental Biology of Fishes. 71, 53-61.

Saquet, M., Halden, N.M., Babaluk, J.A., Campbell, J.L. & Nejedly, Z. (2002) Micro-PIXE analysis of trace element variation in otoliths from fish collected near acid mine tailings: potential for monitoring contaminant dispersal. Nuclear Instruments and Methods B 189, 196-201

Babaluk, J.A., Campbell, J.L. Evans, C.L., Halden, N.M., Mejia, S.R., Nejedly Z., Reist, J.D. and  Teesdale, W.T. (2002) Micro- PIXE analysis of strontium in Arctic char otoliths from Quttinirpaaq National Park, Nunavut, Canada. Nuclear Instruments and Methods B 189, 190-195.

Campbell, J.L., Babaluk, J A., Cooper, Grime, W., Halden, N.M., Nejedly  Z., Rajta, I. and Reist, J.D. (2002) Strontium distribution in young-of-the-year Dolly Varden otoliths: potential for stock discrimination Nuclear Instruments and Methods B 189, 185-189.

Halden, N.M., Mejia, S.R., Babaluk J.A., Reist J.D., Kristofferson, A.H., Campbell, J.L.and Teesdale, W.T. (2000) Oscillatory zinc distribution in Arctic char (Salvelinus alpinus) otoliths: the result of biology or environment?  Fisheries Research 46, 289-298.

Meldrum, A. and Halden, N.M. (1999) Fine-scale oscillatory banding in otoliths from arctic charr (salvelinus alpinus) and Pike (Esox Lucius) Mat. Res. Soc. Symp. Proc. Vol. 489.167-172.

Babaluk, J.A., Halden, N.M., Reist, J.D., Kristofferson, A.H., Campbell, J.L., Teesdale, W.J., (1997) Evidence for non-anadromous behaviour of Arctic charr (Salvelinus alpinus) from Lake Hazen, Ellesmere Island, Northwest Territories, Canada, based on otolith strontium distribution. Arctic. 50, 224-223.

Halden, N.M., Babaluk, J.A., Kristofferson, A.H., Campbell, J.L., Teesdale, W.J., Maxwell, J.A. and Reist, J.D. (1996). Micro-PIXE studies of Sr zoning in Arctic         charr otoliths: migratory behaviour and stock discrimination. Nuclear Instruments and Methods in Physics Research B 109/110 592-597.

Halden, N.M., Babaluk, J.A., Campbell, J.L., Teesdale, W.J. (1995) Scanning proton microprobe analysis of strontium in Arctic char : implications for the interpretation of anadromy. Environmental Biology of Fishes. 43, 333-339.

Babaluck, J.A., Halden, N.M., Reist, J.D., Kristofferson, A.H., Campbell, J.L., Teesdale, W.J.(1995) To sea or not to sea - evidence for non-anadromous behaviour of Arctic char {Salvelinus alpinus} from Lake Hazen, Ellesmere Island, Northwest Territories. 75th Annual meeting of the American Society of Ichthyologists and Herpetologists. Edmonton, Canada.



Halden, N. M., Friedrich, L. A., Babaluk, J. A. & Wastle R.J.  (2005) Trace Element Distributions in Lake Trout Otoliths: Indicators of Life Histories and Environmental Conditions? 2nd Annual North American Trout Symposium Yellowknife August 18-20.

Friedrich, L.A. and Halden, N.M. (2005) Alkali element uptake in otoliths: a link between geography and otolith microchemistry Society of Environmental Toxicology and Chemistry: Baltimore November 17 -19.

Halden, N.M., Campbell, J.L. and Babaluk J.A. 2004 Scanning proton microprobe analysis of lake sturgeon pectoral fin rays: micro-chemical variation and life history information. 10th International Conference on Particle Induced X-ray Emission and its Analytical Application 4-8 June, 2004, Congress Centre Bernardin, Portoro, Slovenia


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