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The Sudbury, ON, Canada region has been the site of metal mining and processing operations for more than 100 years. The study site for my thesis, Junction Creek, flows southwest through the City of Greater Sudbury and receives cumulative inputs including from the Garson Mine wastewater treatment plant (WWTP), Nolin Creek WWTP (stormwater) and CVRD Inco Limited WWTP (process water) as well as effluent from municipal WWTPs and untreated urban runoff, aerial deposition and historical contamination from multiple sources. Elevated levels of ammonia, Ni, Cu, Co, Pb and As, as well as reduced benthic invertebrate community diversity and density have been observed in the Junction Creek system below certain mine inputs. In addition, the Sudbury region has cold winters, with average daily air temperatures below 0°C from November to March.<p> The winter stress syndrome hypothesis proposes that the combination of winter conditions and contaminants (acting as physiological stressors) in the aquatic environment could reduce fish condition and deplete energy (lipid) reserves to the point of decreased survival, thus negatively impacting wild fish populations. However the winter stress syndrome hypothesis has rarely been tested in the field. I hypothesized that juvenile fish challenged with a physiological stressor (treated wastewater) in combination with winter conditions would have decreased growth and energy stores as a result of increased metabolism.<p> The approach I used to examine the potential effects of treated metal mine and municipal wastewaters on bioenergetics and growth, as they related to overwinter survival potential and the winter stress syndrome, of juvenile fish was a combination of a field study and a laboratory experiment. The first objective was to test the winter stress syndrome hypothesis under field conditions. Juvenile fathead minnows (Pimephales promelas), creek chub (Semotilus atromaculatus) and white sucker (Catostomus commersoni) were collected in fall and the following spring from sites along Junction Creek, Sudbury, ON downstream of two metal mining wastewater treatment plants as well as a municipal wastewater treatment plant. The second objective was to test the winter stress syndrome hypothesis in the laboratory by determining the effect of diluted (45 percent) treated CVRD Inco Limited wastewater effluent (CCWWTP) on juvenile fathead minnow growth and energy storage under simulated summer and winter conditions of reduced temperature, photoperiod and food ration. The effect on growth and energy storage of exposure to environmentally relevant ammonia concentrations was also assessed. In both the field and laboratory portions of this study, overwinter survival potential was assessed indirectly through measurements of growth (length, weight, muscle RNA/DNA ratio, muscle proteins) and energy stores (whole body triglycerides). There were inconsistent effects between the field study and the laboratory experiment. In contrast to my hypothesis, fathead minnows in the field study were larger with greater triglyceride stores at exposure sites compared to the reference site. White suckers were smaller at exposure sites but did not differ in triglycerides among sites and creek chub had no clear trend. For the laboratory portion of this study, only fathead minnows were used. After a 90 day exposure to reference or diluted CCWWTP water under simulated winter or summer conditions, juvenile fathead minnows raised in winter CCWWTP water (4°C) had lower whole body triglyceride concentration than those raised in winter reference water. There was no difference in triglycerides in fathead minnows raised in diluted CCWWTP or reference water under summer conditions. This lends support to the winter stress syndrome hypothesis, but the traditional measures of growth showed no significant differences in any of the treatments. In a separate experiment, fathead minnows were exposed from 10-100 days post hatch to graded concentrations of ammonia (0.02 to 0.40 mg unionized NH3/L) under summer conditions only. There was no effect of ammonia exposure on growth parameters, but a significant increase in total body triglycerides at the highest exposure concentration (0.40 mg/L) was observed.<p> The results of this study emphasize that laboratory-based hypotheses must be tested in the field to determine their environmental significance. The winter stress syndrome may not apply to northern fish adapted to living and feeding in colder climates and was not strongly supported by my study.

The Sudbury, ON, Canada region has been the site of metal mining and processing operations for more than 100 years. The study site for my thesis, Junction Creek, flows southwest through the City of Greater Sudbury and receives cumulative inputs including from the Garson Mine wastewater treatment plant (WWTP), Nolin Creek WWTP (stormwater) and CVRD Inco Limited WWTP (process water) as well as effluent from municipal WWTPs and untreated urban runoff, aerial deposition and historical contamination from multiple sources. Elevated levels of ammonia, Ni, Cu, Co, Pb and As, as well as reduced benthic invertebrate community diversity and density have been observed in the Junction Creek system below certain mine inputs. In addition, the Sudbury region has cold winters, with average daily air temperatures below 0°C from November to March.<p> The winter stress syndrome hypothesis proposes that the combination of winter conditions and contaminants (acting as physiological stressors) in the aquatic environment could reduce fish condition and deplete energy (lipid) reserves to the point of decreased survival, thus negatively impacting wild fish populations. However the winter stress syndrome hypothesis has rarely been tested in the field. I hypothesized that juvenile fish challenged with a physiological stressor (treated wastewater) in combination with winter conditions would have decreased growth and energy stores as a result of increased metabolism.<p> The approach I used to examine the potential effects of treated metal mine and municipal wastewaters on bioenergetics and growth, as they related to overwinter survival potential and the winter stress syndrome, of juvenile fish was a combination of a field study and a laboratory experiment. The first objective was to test the winter stress syndrome hypothesis under field conditions. Juvenile fathead minnows (Pimephales promelas), creek chub (Semotilus atromaculatus) and white sucker (Catostomus commersoni) were collected in fall and the following spring from sites along Junction Creek, Sudbury, ON downstream of two metal mining wastewater treatment plants as well as a municipal wastewater treatment plant. The second objective was to test the winter stress syndrome hypothesis in the laboratory by determining the effect of diluted (45 percent) treated CVRD Inco Limited wastewater effluent (CCWWTP) on juvenile fathead minnow growth and energy storage under simulated summer and winter conditions of reduced temperature, photoperiod and food ration. The effect on growth and energy storage of exposure to environmentally relevant ammonia concentrations was also assessed. In both the field and laboratory portions of this study, overwinter survival potential was assessed indirectly through measurements of growth (length, weight, muscle RNA/DNA ratio, muscle proteins) and energy stores (whole body triglycerides). There were inconsistent effects between the field study and the laboratory experiment. In contrast to my hypothesis, fathead minnows in the field study were larger with greater triglyceride stores at exposure sites compared to the reference site. White suckers were smaller at exposure sites but did not differ in triglycerides among sites and creek chub had no clear trend. For the laboratory portion of this study, only fathead minnows were used. After a 90 day exposure to reference or diluted CCWWTP water under simulated winter or summer conditions, juvenile fathead minnows raised in winter CCWWTP water (4°C) had lower whole body triglyceride concentration than those raised in winter reference water. There was no difference in triglycerides in fathead minnows raised in diluted CCWWTP or reference water under summer conditions. This lends support to the winter stress syndrome hypothesis, but the traditional measures of growth showed no significant differences in any of the treatments. In a separate experiment, fathead minnows were exposed from 10-100 days post hatch to graded concentrations of ammonia (0.02 to 0.40 mg unionized NH3/L) under summer conditions only. There was no effect of ammonia exposure on growth parameters, but a significant increase in total body triglycerides at the highest exposure concentration (0.40 mg/L) was observed.<p> The results of this study emphasize that laboratory-based hypotheses must be tested in the field to determine their environmental significance. The winter stress syndrome may not apply to northern fish adapted to living and feeding in colder climates and was not strongly supported by my study.

O objetivo deste trabalho foi avaliar o efeito do colostro bovino liofilizado (CBL), utilizado como fonte parcial da dieta protéica, sobre as características histológicas do epitélio intestinal de juvenis de pacu (Piaractus mesopotamicus) e dourado (Salminus brasiliensis). Os juvenis foram distribuídos num delineamento experimental inteiramente casualizado em esquema fatorial 3x2. Foram utilizadas dietas com três níveis de inclusão de CBL (0%, 10% e 20%) e dois períodos experimentais (30 e 60 dias), oferecidas duas vezes ao dia até a saciedade aparente. Para o estudo histológico, o intestino foi dividido em três segmentos, S1, S2 e reto para pacu e S1, S2 e intestino posterior para dourado. Foram avaliadas a espessura da camada muscular; o volume parcial da mucosa absortiva (Vv); o número das células caliciformes contendo mucinas ácidas e neutras e totais, e os subtipos ácidas - sialomucinas e sufomucinas. Nos juvenis de pacu, a inclusão de 20% de CBL alterou a distribuição das células caliciformes contendo as mucinas ácidas, neutras e totais, os subtipos sialomucinas e sulfomucinas, e a espessura da camada muscular, enquanto o Vv foi afetado apenas pelo período experimental. Nos juvenis de dourados, efeito de período experimental foi observado para células caliciformes contendo mucinas ácidas, neutras e totais e os subtipos sialomucinas e sulfomucinas, espessura da camada muscular e Vv. A adição de 10% de CBL afetou apenas o Vv no segmento S1. Considerando os aspectos avaliados no presente estudo, a presença do colostro bovino liofilizado na dieta influenciou, no período estudado, as características histológicas entéricas de juvenis de pacu, enquanto que nos juvenis de dourado influencia desta secreção láctea não foi observada. / The aim of this study was to evaluate the effect of lyophilized bovine colostrum (LBC), used as partial source of protein in the diet, on the histological characteristics of the intestinal epithelium of juvenile pacu (Piaractus mesopotamicus) and juvenile dourado (Salminus brasiliensis). Juveniles were distributed in a completely randomized design in a factorial scheme 3x2. Three diets were used with different levels of LBC inclusion (0%, 10% and 20%) and two experimental periods (30 and 60 days) offered twice daily until apparent satiation. For the histological study, the intestine was divided into three segments, S1, S2 and rectum to the pacu and S1, S2 and posterior intestine to the dourado. The muscle layer thickness; the mucosal absorptive volume (Vv); the number of goblet cells containing acidic and neutral mucins and the acidic subtypes - sialomucin and sulphomucin were evaluated. In juvenile pacu, the inclusion of 20% of LBC changed the distribution of goblet cells containing acidic, neutral and total mucins, the subtypes sialomucins and sulphomucins, and the thickness of the muscle layer, while the Vv was affected only by the experimental period. In juvenile dourado, effect of experimental period was observed for goblet cells containing acidic, neutral and total mucins and subtypes sialomucins, sulphomucins, thickness of muscle layer and Vv. The addition of 10% of LBC affected only Vv in the segment S1. Considering the aspects studied, the presence of lyophilized bovine colostrum in the diet influenced, in the period studied, the enteric histological characteristics of juvenile pacu, while the juvenile dourado influence of this lacteal secretion was not observed.

Selenium (Se) is known to cause chronic toxicity in aquatic species. In particular, dietary exposure of fish to selenomethionine (SeMet), the primary form of Se in the diet, is of concern. Previous studies reported that chronic exposure to elevated dietary SeMet altered swimming performance, aerobic metabolism, and energy and endocrine homeostasis in adult fish. However, little is known about the direct effects of dietary SeMet exposure in juvenile fish. Therefore, the overall objective of this thesis was to investigate sublethal pathophysiological effects of subchronic dietary SeMet exposure in two juvenile fish species, fathead minnow (Pimephales promelas) and rainbow trout (Oncorhynchus mykiss). In the first experiment, 20 days post hatch (dph) juvenile fathead minnow were exposed to different measured concentrations (2.8, 5.4, 9.9, 26.5 µg Se/g dry mass [dm]) of Se in food in the form of SeMet for 60 days. In the second experiment, 14 dph juvenile rainbow trout were exposed for 37 days to different measured concentrations (1.0, 4.1, 11.2, 26.1 µg Se/g dm) of Se in food in the form of SeMet. Following exposure, samples were collected for Se analysis and fish were subjected to a swimming performance challenge to assess critical swim speed (Ucrit), tail beat frequency and tail beat amplitude, oxygen consumption (MO2), cost of transport (COT), standard metabolic rate (SMR), active metabolic rate (AMR), and factorial aerobic scope (F-AS). Dietary SeMet exposure impaired swimming ability in both fathead minnow and rainbow trout. Juvenile fathead minnow showed alterations in aerobic metabolism with increased MO2, COT and AMR at the 9.9 and 26.5 µg Se/g diets, while dietary SeMet exposure did not appear to affect aerobic metabolism in juvenile rainbow trout. After swim performance experiments, swam fish were considered fatigued and metabolic and energy storage endpoints were compared to non-swam (non-fatigued) fish. Energy storage capacity was measured via whole body (fathead minnow) and liver and muscle (rainbow trout) triglyceride and glycogen concentrations. For fathead minnow, triglyceride concentrations in non-swam fish were significantly elevated in the 5.4 µg Se/g group relative to controls, and swam fish had significantly lower whole body triglycerides than non-swam fish. All non-swam SeMet exposure groups had significantly decreased whole body glycogen concentrations compared to controls while the 5.4 and 26.5 µg Se/g exposure groups had significantly greater whole body glycogen concentrations in swam versus non-swam fish. In juvenile rainbow trout, liver triglyceride concentrations were significantly lower in all SeMet exposed groups compared to controls in non-swam fish. Swimming decreased liver and muscle triglycerides in the control and 11.2 µg Se/g treatment groups. Liver glycogen concentrations were greater in swam trout in the 4.1 µg Se/g dm exposure group. Muscle glycogen concentrations in non-swam fish, were significantly decreased in the 4.1 and 11.2 µg Se/g exposed groups compared to controls, while muscle glycogen in swam fish was unaffected by dietary SeMet exposure. For the swim status factor, muscle glycogen concentrations were significantly greater in swam versus non-swam trout in all treatment groups. Therefore, dietary SeMet exposure caused impaired swimming performance and metabolic alterations in both juvenile fathead minnow and juvenile rainbow trout. Species differences were apparent, especially in the patterns of altered energy status between swam and non-swam fish exposed to Se. Overall, the pathophysiological implications of these sublethal effects are unclear, but suggest that dietary SeMet exposure may negatively influence juvenile fish survivability in natural habitats.

The condition of juvenile fish relates to their overall health and is a strong predictor of survival and eventual recruitment. Condition can be quantified and interpreted in a variety of ways covering different time scales and levels of biological organization. Here I (i) quantify interannual variability in the condition in Young-of-Year (YOY) Pacific herring (Clupea pallasi) in the Strait of Georgia, BC, from 2013-2016, and (ii) examine the extent to which the condition of an individual fish varies depending on which condition metric is used. Chapter 1 provides a general background on the concept of measuring condition in fish, as well as the basic biology of Pacific herring and their importance in Strait of Georgia ecosystem. In Chapter 2, I report the condition of YOY herring from 2013-2016 using six metrics: (i) Fulton’s K, (ii) the residuals from a length:weight regression, (iii) the RNA:DNA ratio, (iv) recent growth estimated via otolith microstructure analysis, (v) lipid content, and (vi) the ratio of two essential acids DHA:EPA. Four of these metrics (Fulton’s K, length:weight residuals, and growth from RNA:DNA and otolith increments) indicate a decrease in condition over the four years. In contrast, lipid content suggests an increase across the four years, while DHA:EPA suggests a decrease in 2015 but no change over the other three years. The observed interannual variability in condition can be partly linked to unfavourable changes in temperature and zooplankton community composition in 2015 and 2016, and to the propensity of juvenile fish to prioritize energy storage over somatic growth before a period of prey scarcity, such as their first winter. This dataset is further examined in Chapter 3, wherein I examine variability in condition of individual fish based on the different metrics used. Individual herring are ranked based on their scores from the six different metrics of condition, and the distribution of these rankings are examined to assess the degree of intercorrelation among the metrics. Based on this model, as well as pairwise Spearman rank correlations between the six metrics, I conclude that there is little intercorrelation between metrics, and that a fish that scores highly in terms of condition in any one metric will not necessarily score highly for the other metrics. These findings underscore the importance of choosing condition metrics carefully, based on the nature of the question being asked. / Graduate / 2019-07-04

The thesis compares variability of mercury concentration among adult and juvenile fish in order to streamline monitoring of water environment contamination. In terms ov thw thesis there were monitored two localities: Labe Děčín and Labe Kozly. Adult fish were caught usingdeep-water electrofishing equipment and juvenile fish were caught using back-pack electrofishing equipment. Two variations of mercury concentration were compared, one in muscle of particular adult fish species, second in whole bodies of juvenile fish. Mercury concentrations were also compared among particular juvenile fish fish species in particular localities. All analyses were performed using spectrophotometer AMA 254. It was proved that analyses of juvenile fish are suitable and more cheaper than analyses of adult fish, when it comes to monitoring.

0+ fish communities of the littoral zone were sampled in the Římov Reservoir within the years 2007-2011. The goal of the thesis among other things was monitoring 0+ fish during five years in littoral habitats of Římov reservoir depending on year-class strength environmental factors, etc., and also find general distribution model, which can explain spatial distribution of juvenile fish in canyon-shaped reservoir. Results of this thesis could be used for another reservoirs which coincide with environmental condition of Římov reservoir.

Some shallow (<7m, water depth) nearshore hardbottom areas of Southeast Florida have been reported to function as important juvenile habitat. I characterized the nearshore fish communities along a 30km stretch of coastline of Broward County, Florida from visual census data. Two-hundred transect-counts, 100 point-counts and 98 rover-diver counts were completed by myself and others during June-August, 2001. The abundance of all fish species and their sizes were recorded. The transects (30m long, 2m wide, 1m high) were laid perpendicular (compass heading 90°) to the innermost edge of hardbottom. Transects were placed every 152m of coastline. Altemately, a point-count or 20 min rover-diver count was also performed over the hard bottom just north of the 30m transect. All counts occurred between approximately 2m and 6m water depth. One hundred-sixty nine species and over 72,000 fish were recorded. Recently settled juveniles (≤ 5cm) were the dominant component (>80%) of the inshore fish community, consisting primarily (>90%) of grunts (Haemulidae).

Abstract The degradation of rivers and streams has led to world-wide efforts to restore freshwater habitats. A good understanding of the social-ecological context is considered key to successful restoration. In this thesis, a multidisciplinary framework was applied to study ecological and social dimensions of restoration success. First, the long-term performance of in-stream restoration measures was examined by conducting repeated cross-sectional surveys in restored streams up to 20 years post-restoration. Next, nationwide electrofishing data were used to assess the density responses of juvenile salmonids to habitat restoration and factors influencing restoration success were examined. Finally, changes in the provision of ecosystem services were evaluated by comparing the perceptions of restoration outcomes between two user groups and three study rivers. The results indicated that the restoration-induced increase in habitat heterogeneity persisted over time, initiating an overall positive development also in biological metrics (i.e. juvenile salmonids and aquatic mosses). However, overall substrate variability in restored streams remained lower than in near-pristine streams, with a shortage of gravel beds. Fish responses varied strongly between rivers, which was explained mainly by watershed scale (e.g. river basin size, dominant geology) and local (potential interspecific competition) factors. Site-specific differences were also observed in the delivery of ecosystem services, mainly reflecting stakeholder perceptions of landscape value and fish provisioning. Overall, the results show that setting indicators and target levels for restoration success is grounded on perspective. Socially conscious ecological restoration that acknowledges local specialities and needs in priority setting, planning and implementation has the potential to provide multiple benefits for river ecosystems and society. / Tiivistelmä Virtavesien ekologisen tilan heikentyminen on johtanut maailmanlaajuisiin toimiin niiden elinympäristöjen kunnostamiseksi. Usein ekologisen kunnostuksen onnistuminen edellyttää kuitenkin ihmisen ja ympäristön vuorovaikutussuhteiden laaja-alaista ymmärtämistä. Tässä väitöskirjatutkimuksessa käytettiin monitieteistä viitekehystä virtavesikunnostusten ekologisten ja sosiaalisten vaikutusten tutkimiseen. Ensimmäisessä osatyössä arvioitiin kunnostustoimenpiteiden kestävyyttä sekä uoman rakenteellisen monimuotoisuuden kehittymistä pitkällä aikavälillä (10-20 vuotta kunnostusten jälkeen). Toisessa osatyössä tehtiin valtakunnallisen sähkökalastusaineiston avulla meta-analyysipohjainen yhteenveto suomalaisten virtavesikunnostusten vaikutuksista taimenen ja lohen kesänvanhojen (0+) poikasten tiheyteen sekä tutkittiin kunnostustulokseen vaikuttavia ympäristötekijöitä. Kolmannessa osatyössä selvitettiin kunnostusten onnistumista ekosysteemipalvelujen näkökulmasta vertaamalla kahden eri käyttäjäryhmän kokemia muutoksia kolmen tutkimusjoen välillä. Väitöskirjan tulokset osoittivat, että kunnostukset lisäsivät jokiuoman rakenteellista monimuotoisuutta sekä lyhyellä että pitkällä aikavälillä ja vaikuttivat myönteisesti myös biologisiin indikaattoreihin (lohikalojen poikastiheys ja vesisammalet). Vaihtelu pohjan laadussa oli kuitenkin luonnontilaisia uomia vähäisempää ja erityisesti kutuun soveltuvaa soraa oli niukasti. Lohikalojen tiheysvaste vaihteli voimakkaasti jokien välillä, mikä selittyi pääasiassa valuma-alueeseen liittyvillä (esim. valuma-alueen koko ja geologia) ja paikallisilla (mahdollinen lajien välinen kilpailu) tekijöillä. Paikkasidonnaisia eroja havaittiin myös vaikutuksissa ekosysteemipalveluihin ja ne heijastivat etenkin maisemassa ja kalasaaliissa koettuja muutoksia. Tutkimus osoitti, että erilaiset taustat ja odotukset vaikuttavat vahvasti siihen, millaisten kriteerien perusteella kunnostusten onnistumista arvioidaan. Jotta kunnostuksilla saavutettaisiin hyötyjä sekä jokiekosysteemeille että yhteiskunnalle, on tärkeää tuntea paikalliset erityispiirteet ja -tarpeet ja ottaa ne huomioon kunnostuskohteiden valinnassa sekä toimenpiteiden suunnittelussa ja toteutuksessa.