1983. Evidence of acidification sf some Nova Scotian rivers and its impact on Atlantic salmon, Salmo snlar. Can. J. Fish. Aquat. Sci. 40: 462-473.River pH's in Nova Scotia are closely reIated to geology, and seasonal pH variation is well correlated with river discharge rates. In the geologically sensitive areas (granite and metamorphic rocks), river pH's have fallen significantly over the past 27 yr at an apparent average rate of 0.017 pH units/year. Concomitant with this decrease are a decline in HCOi concentrations and increases in AIWC and SOT. On average, 73% of the increase in acid is attributabie to increased SOT. Changes in Na', K9, Ca'+. and Mg" concentrations were not significant. In rivers presently at mean annual pH's c4.7, the Atlantic salmon (S~lrno s a k r ) runs have disappeared and are presumed extinct. Rivers in the pH range 4.7-5.0 show a decline in salmon angling returns of 2.8%/yr, beginning about 1854, and low densities of juvenile salmon. Rivers presently of pH > 5.0 generally have normal juvenile densities and show no significant trend in angling returns. WATT, W. D., $1. B. SCOTT, AND W. J. WHITE. 1983. Evidence of acidification of some Nova Scotian rivers and its impact on Atlantic salmon, Snlrno solar. Can. 5. Fish. Aquat. Sci. 44): 462-473. En Pdouvelle-kcosse, le pH des rivieres est en ktroite relation avec la geologic. et les variations saisonnihes le sorat avec le dkbit des rivikres. Dans les regions gt5ologiques plus sensibaes (granite et r o c k s mktamorphiques). le pH des rivikres a baisse de faqon significative au cours des 27 dernikres annkes et cela 5 un taux moyen de 0.017 unit& pH/annCe. 11 s'est produit en m6me temps un dCclin de concentration de HCOi et un aceroissement de Al"' et SO:. En moyenne, 73 % de I'augmentation de l'acide est attribuable a l'augmentation de SO:. Drarant la mCme @riode, il ne s'est produit aucun ehangement significatif des concentrations de Na', K', Ca'* et Mg". Les populations de saumsns ataantiques (Saltno salar) ont disparu des rivi5res dont le pH annuel moyen est infbrieur B 4,7 et sont pr6sumkes Cteintes.Les rivikres B pH de 4,7-5,0 montrent un dCclin des prises sportives de 2,8 % par annie patir de 1954 et de faibies densites de juvkniles. Les rivieres B pH srm@rieur a 5,0 snt en gCn6ral des densitCs de saumoneaux normales et ne montrent abscune tendance significative des prises sportives.

A simple, inexpensive fish tag that allows for growth of the fish is described. Growth rates of smallmouth bass were not significantly affected by tagging. The rate of retention on smallmouth bass was much higher than that for a tag described by Fraser but rates of retention of the two tags on largemouth bass were not significantly different. Estimated rates of tag loss were 15% after 1 year for smallmouth bass and 17% after 3 years for largemouth bass. Observed tag losses from white suckers over 3 years were only 0.6%.Using this method, two or three persons can conveniently tag fish at a rate of approximately 30 per hour.

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PurposeThe nonspecific terms “wrist sprain” and “suspected occult bony injury” are frequently documented as diagnoses in occult paediatric wrist injuries. To date, however, no one has accurately defined their true underlying pathology. The primary objective of this study was to identify the true pathoanatomy of occult acute paediatric wrist injuries. Our secondary objective was to compare our findings with existing adult data in order to determine any population differences that might be clinically relevant.MethodsWe performed a single-centre retrospective case series evaluating MRI findings in acute paediatric wrist injuries presenting to the hand injury unit between 2011 and 2014. All patients underwent standardised radiographs of the wrist and, where clinically indicated, of the scaphoid. Where no bony anomaly was identified, MRI scanning was offered. Cohen’s kappa coefficient was used to calculate the agreement between clinical and MRI diagnosis.Results57 patients met the final inclusion criteria. Occult fractures and bony contusions comprised the majority of the pathologies, at 36.5 and 35.0 %, respectively. There were no cases of isolated soft-tissue injury. MRI effected management change in 35.1 % of cases. Paediatric wrists demonstrated differences in injury pattern and distribution when compared to an adult population.ConclusionThis study defines for the first time the true pathology of occult paediatric wrist injuries. The current definition of a wrist sprain was not applicable to a single case and therefore appears to be inappropriate for use in the paediatric population. A precise knowledge of the likely pathology facilitates accurate information delivery whilst reducing parental uncertainty and treatment variation.