Rich David Moccia

University of Guelph | UOGuelph · Department of Animal Biosciences

Purpose This investigation forms part of a wider study into the legacy effects of exposure of rainbow trout eggs 38h after fertilisation, eyed eggs, yolk sac larvae (YSL) or first feeders to a single 0.5 Gy X-ray dose, including the induction of a bystander effect, by the irradiated fish, to non-irradiated fish. Fish may be exposed to multiple envi...

Salmonid welfare

The heavy reliance of most global aquaculture on the ambient environment suggests inherent vulnerability to climate change effects. This review explores the potential effects of climate change stressors on aquaculture biology and resources needed to support decision-making for vulnerability assessment, planned adaptation, and strategic research dev...

Increases in global population and seafood demand are occurring simultaneously with fisheries decline in an era of rapid climate change. Aquaculture is well positioned to help meet the world's future seafood needs, but heavy reliance of most global aquaculture on the ambient environment and ecosystem services suggests inherent vulnerability to clim...

Ultraviolet (UV) irradiation is commonly used to control pathogen loads in recirculation aquaculture systems (RAS), although these micro-organisms can be shielded by particles in the water, and some species tolerate very high UV doses. The objective of this study was to evaluate membrane filtration (MF) as an alternative, or complimentary, treatmen...

Anthropogenic subsidies occur readily, especially with growing human development neighboring natural systems. Determining how these subsidies permeate into native food webs is important, but currently not well understood. Here, we used a combination of stable isotopes and fatty acids as bio-tracers to explore the pathway(s) of assimilation of an an...

Aims: The objective was to determine the effects of dietary substitution of fishmeal with live yeast and increasing water temperature on the diversity and composition of gut microbiota in rainbow trout. Methods and results: Fish were fed either fishmeal or yeast (Saccharomyces cerevisiae) and reared in water temperatures of either 11 °C (cold) o...

This study extends the investigation of the legacy effects of exposure to a single radiation dose at one of four early life stages, in adult rainbow trout (Part A), by examining the effects of a second identical dose after one year; i.e. egg 48 h after fertilisation (48 h egg) + 1 year, eyed egg + 1 year, yolk sac larvae (YSL) + 1 year and first fe...

Exposure to a single 0.5 Gy X-ray dose of eggs at 48 h after fertilisation (48 h egg), eyed eggs, yolk sac larvae (YSL) and first feeders induces a legacy effect in adult rainbow trout. This includes the transmission of a bystander effect to non-irradiated adult trout which had swam with the irradiated fish. The aim of this study was to investigate...

Rainbow trout (Oncorhynchus mykiss) were fed for 10 weeks on a diet containing either 30% fish meal (FM) or with 20, 40 and 60% replacement of fish meal protein with Saccharomyces cerevisiae (SC) or a mixture of Wickerhamomyces anomalus and S. cerevisiae (WA). Luminal contents and mucosal tissue from the distal intestine were collected and analysed...

The bystander effect, a non-targeted effect (NTE) of radiation, which describes the response by non-irradiated organisms to signals emitted by irradiated organisms, has been documented in a number of fish species. However transgenerational effects of radiation (including NTE) have yet to be studied in fish. Therefore rainbow trout, which were irrad...

Purpose: To determine if the legacy of early life stage irradiation seen in rainbow trout is modified in adult fish by acute exposure to waterborne aluminium (Al). Methods: Two-year-old trout which had been irradiated as either eggs 48 h after fertilization, eyed eggs, yolk sac larvae or as first feeders, were exposed to 100 or 200 μg l(-1) Al....

To investigate if aluminium (Al) modifies the rainbow trout response to radiation exposure and / or the induction of a radiation induced bystander effect. Rainbow trout were exposed to 100 or 200 µg l(-1) Al (for 3 hours), a 0.5 Gy X-ray dose or Al followed immediately by irradiation. The exposed fish were then swum with completely untreated bystan...

Purpose: To extend the investigations of bystander effect induction in fish of the same species as the irradiated fish, to bystander effect induction between fish species and between trophic levels. Materials and methods: To investigate interspecies bystander effect induction, zebrafish and medaka were irradiated with a 0.5 Gy X-ray dose and the...

Embryological studies of the teleost lens have attracted little attention. The morphology of the rainbow trout (Oncorhynchus mykiss) lens during embryonic development was investigated using light microscopy. Results indicate that in general, the embryology of the rainbow trout lens proceeds much like that which has been described for other vertebra...

Communication of signals from irradiated to non-irradiated fish has been demonstrated by our group for adults. Major questions are however, whether the effects persist for significant lengths of time (meaning there are memories or legacies of the exposure) and whether they are induced in young animals or very early stages in the life cycle. To addr...

Knowledge of the quantitative and qualitative properties of salmonid faeces is necessary for aquaculture waste dispersal models, and the design of integrated multi-trophic aquaculture (IMTA) systems. The amount and proximate composition of salmonid faeces can be estimated using a mass-balance, nutritional approach. Indigestible components of salmon...

Minimizing phosphorus (P) wastes is considered to be a key factor for environmental sustainability of freshwater aquaculture operations in many parts of the world. A factorial P model, consisting of digestibility, whole-body P deposition, P waste output and limnological transformation sub-models, was constructed to simulate the effects of different...

The anaesthetic effects of clove-oil-derived eugenol were studied in juvenile rainbow trout, Oncorhynchus mykiss (Walbaum). Acute lethality and the effects of multiple exposures to eugenol were measured. The estimated 8-96 h LC50 for eugenol was found to be approximately 9 p.p.m. Times to induction and recovery from anaesthesia were measured and co...

Rainbow trout, Oncorhynchus mykiss (Walbaum), with a mean initial weight of 196 g were fed the β-agonist ractopamine incorporated into a commercial rainbow trout diet at 0, 5, 10, 20 or 40 p.p.m. for 12 weeks. The experiment was conducted as a completely randomized design, with five treatments and four replicate tanks. At the start of the trial and...

Ractopamine is a synthetic catecholamine analogue which is known to affect the growth performance of both terrestrial and aquatic livestock species when it is incorporated into their feed. To investigate the effect of ractopamine on fish, rainbow trout, Oncorhynchus mykiss (Walbaum), (initial weight = 385.2 ± 1.4 g) were fed six iso-energetic (16.6...

Trout learned the operant task of pendulum-pressing for a food-reward in a mean of 4.3 sessions lasting 1 hr. In a separate phase, fish also learned--through classical conditioning--to associate a neutral light cue with an aversive stimulus. When again allowed to pendulum-press for food, after aversive classical conditioning, there was a drop in th...

Aquatic total phosphorus (Tot-P) is measured 30 m distant from rainbow trout (Oncorhynchus mykiss) cages, for regulatory compliance on the Canadian side of Lake Huron. The ability to predict changes in near-field Tot-P concentrations from changes in production, or to explain near-field concentrations in the event of compromised reference sites, wou...

Embryo somatic tissues, non-somatic yolk-sac materials, and whole, individual fingerlings (age 0+) of Arctic charr, Salvelinus alpinus (L.), as well as a commercial trout diet, were analysed for a wide spectrum of amino acids. Analytical material consisted of prefeeding swim-up fry that were separated into discrete yolk sac and somatic embryo tissu...

Several fish species of the genus Salvelinus are used for stocking freshwaters in North and South America and much of Europe but there is little information about their growth and carcass composition. Lake trout (S. namaycush), brook trout (S. fontinalis) and their hybrid F1 splake (S. namaycush × S. fontinalis) (initial body weight ca. 2–4 g) were...

The purpose of the study was to investigate whether dietary ration or diet composition influence the relationship between plasma growth hormone (GH) and insulin-like growth factor-1 (IGF-1) in Arctic charr (Salvelinus alpinus L.). The pattern of changes in plasma GH and IGF-1 concentrations was examined in fish fed at different ration levels (0%, 0...

Approaches to managing aquaculture's sustainability have traditionally focused on a relatively few, but important, environmental impact parameters. A broader and more contemporary concept of aquaculture sustainability has now evolved to include various other parameters considered relevant to those multiple stakeholder groups who may be affected by...

Effluents from recirculating aquaculture systems (RAS) contain high concentrations of nitrogen and phosphorous wastes and thus often require proper treatment to prevent potential detrimental impacts on receiving water bodies. The purpose of this study was to evaluate the feasibility of membrane filtration coupled with chemical precipitation as a pr...

Young Arctic charr, Salvelinus alpinus (L.), mean weight 2.56 ± 0.02 g, were fed nine isoenergetic (˜16.6 MJ digestible energy (DE) kg−1) practical diets formulated to supply digestible crude protein (DCP) at 40g kg−1 increments from 230 to 550g kg−1, for 84 days. Mean weight gain (MWG) and specific growth rate (SGR) were determined every 14 days w...

Aquatic total phosphorus (Tot-P) is measured at fish-cages in Lake Huron for environmental regulatory compliance. An improved understanding of how Tot-P is manifested in the near-field (<or=30 m) water column relative to reference sites within the same water body, current movement and farm structures is required to help interpret sample results and...

Little is known about the cognitive and subjective experiences of fish that are confined with conspecifics of varying body sizes. Plasma cortisol and several behavioural variables were recorded when a ȁ8mediumȁ9 sized fish had its familiar social group (comprised of medium, like-sized individuals) replaced with a group of fish that were either medi...

Since 1999, large-scale mortalities of fish-eating birds have been observed on the Great Lakes, and more specifically on Lake Erie. Type E botulism has been established as the primary cause of death. The mechanism of type E botulism exposure in fish-eating birds is unclear. Given that these birds are thought to eat live fish exclusively, it seems l...

In a 4-mo study (June 2004-September 2004), round gobies (Neogobius melanostomas) were dosed orally every 72 hr for up to 21 days with Clostridium botulinum neurotoxin type E (BoNT/E) at one of four doses: 0, 50, 250, and 500 mouse lethal doses (MLD). Fish were observed for changes in pigmentation and behavior for the duration of the experiment. Mo...

Rainbow trout (Oncorhynchus mykiss), round gobies (Neogobius melanostomas), yellow walleye (Stizostedion vitreum), and yellow perch (Perca flavescens) were given Clostridium botulinum neurotoxin type E (BoNT/E) at four doses (0, 800, 1500, and 4000 mouse lethal doses). BoNT/E was sought in the fish tissues at death or at the conclusion of the exper...

Juvenile rainbow trout were exposed to 36, 171, 1017 and 4887 mg/1 of suspended kaolin clay for 64 days. Gills were analysed qualitatively and quantitatively using histology. Branchial pathology was absent at all sample times in fish exposed to 36, 171 and 1017 mg/1 kaolin, although intracellular kaolin was visible within filament and lamellar epit...

First-feeding Arctic char Salvelinus alpinus were subjected to two different photoperiods (light conditions at latitude 43°28′N [normal] and 24 h of continuous light) and two different feeding schedules (fed only during the natural photoperiod [normal] and 24-h continuous feeding) for 12 weeks. Arctic char subjected to 24 h of continuous light and...

Behavioural and energetic responses of domesticated rainbow trout Oncorhynchus mykiss (Walbaum) (mean fork length=440±45 mm) to a brief transportation episode were investigated. Fish implanted with radio transmitters measuring muscle activity (electromyogram; EMGi) were transported in a standard commercial shipping tank for 50 min by truck, and the...

Lake trout (Salvelinus namaycush), brook trout (Salvelinus fontinalis) and their hybrid, F1 splake (S. namaycush×S. fontinalis) account for approximately 80% of total fish stocked for lake rehabilitation in Ontario. Yet, little information exists in the literature on the patterns of growth and whole body composition for these species under hatchery...

This study investigated the influence of nutritional status on the growth hormone (GH)/insulin-like growth factor-I (IGF-I) axis in Arctic charr (Salvelinus alpinus). The objectives were to study the regulation of GH secretion in vitro by somatostatin-14 (SRIF) and hIGF-I, and to determine whether pituitary sensitivity to these factors is dependent...

There is growing societal and scientific interest in the welfare status of fish used for commercial enterprise. As animal welfare is primarily concerned with the quality of life of a conscious, sentient organism, the question of whether fishes are even capable of consciousness must first be addressed in order to assess their welfare status. Recentl...

This study involved monitoring the activity levels of three groups of adult rainbow trout that were either fasted on a weekly cycle, fed to satiation, or fed to satiation and then acutely stressed by over-crowding twice weekly. A subsample of fish was implanted with electromyogram (EMG) radio-transmitters that broadcast a signal proportional to mus...

The capacity of rainbow trout to experience fear was assessed using an avoidance learning task. Each of 13 fish was placed individually into a two-chambered shuttle tank where it could be sub-jected to the putative frightening stimulus of a plunging dip net in either chamber. The fish could escape from the stimulus by swimming through a doorway to...

Clove oil has been demonstrated to be an effective, inexpensive anaesthetic and euthanizing agent for a number of fish species, including rainbow trout, used in aquaculture and fisheries research. However, the potential for clove oil to cause perturbations in important plasma hormone concentrations has not been investigated. The effect of anaesthes...

In contrast to other major forms of livestock agriculture, there is a paucity of scientific information on the welfare of fish raised under intensive aquacultural conditions. This reflects an adherence to the belief that these animals have not evolved the salient biological characteristics that are hypothesised to permit sentience. In this review,...

The anesthetic effects of clove-oil-derived eugenol were studied in the zebrafish, Danio rerio (Hamilton). Acute lethality and the effects of exposures to various dosages of eugenol were measured. The estimated 96-h LC50 for eugenol was 21 ppm. Times to induction and recovery from anesthesia were measured and compared with MS-222 under similar cond...

Most aquaculture production in the Great Lakes comes from rainbow trout (Oncorhynchus mykiss) cage-culture in Lake Huron waters. Present environmental regulations require grab samples and spot measurements of total phosphorus (TP) and dissolved oxygen (DO) in the 'near-field' (within 30m) water column. Such proximate measurements often exhibit exte...

Sexually immature Arctic charr, Salvelinus alpinus (Linnaeus), were fed one of five isoenergetic practical diets of differing lipid:protein ratios (0.98, 0.67, 0.41, 0.26, 0.19) for an 84-day period to examine the influence of diet composition on growth, and growth hormone (GH) and thyroid hormone physiology. All five diets supported growth at appr...

The dietary methionine requirement of juvenile Arctic charr Salvelinus alpinus (L.) was assessed by feeding diets supplemented with graded levels of DL-methionine (9, 12, 15, 18, 21, and 24 g kg−1dietary protein) for 16 weeks at 12°C. All diets contained 400 g kg−1 protein, 170 g kg−1 lipid, 66 g kg−1 ash and an estimated 17.5 MJ digestible energy...

The lowest level at which fish farmers ordinarily make management decisions is the individual holding unit. To identify factors associated with chemotherapeutic treatment initiation at the holding-unit level, we created a unit of measurement called the "farm-tank-lot" (FTL), which allowed the movements and mixing of groups of fish to be followed du...

Rainbow trout Oncorhynchus mykiss (Walbaum) are usually cultured at high densities to maximize production, but little is known about the physiological and behavioural consequences of high-density fish culture. The purpose of this study was to develop quantitative correlates of activity for fish held under conditions of increasing density. Fifteen h...

The chemical composition of settleable faecal fish waste was determined from fresh manure samples collected at 12 commercial farms growing rainbow trout Oncorhynchus mykiss in Ontario, Canada. The manure samples from the commercial farms averaged 2.83% nitrogen (N), 2.54% phosphorus (P), 0.10% potassium (K), 6.99% calcium (Ca), and 0.53% magnesium...

Ractopamine is a synthetic catecholamine analogue which is known to improve feed efficiency, reduce carcass fat and increase lean muscle growth in terrestrial livestock (e.g. sheep, pigs, cattle and chickens), and therefore, may be useful in aquaculture production if similar effects can be elicited in fish. In the present study, rainbow trout, Onco...

Farmed Arctic charr, Salvelinus alpinus (L.), (n = 2 70) with a wide range of carotenoid muscle pigmentation were produced by feeding astaxanthin at different levels (0-120 mg kg−1 feed). Steaks were scored subjectively for pigment concentration (dark = high score). Internal reflectance spectra were measured with a relatively non-destructive 1-mm-d...

Effects of transmitter attachment procedures on smolts of Atlantic salmon Salmo salar have primarily been examined in the laboratory with hatchery-reared fish. Biotelemetry researchers must extrapolate findings of tagging studies to wild, migrating smolts. Because hatchery rearing can affect salmonid development and because field tagging procedures...

In the subjective evaluation of carotenoid coloration in market-size Arctic charr, scores for external skin color were correlated negatively with scores for the internal musculature (r = −0.65, P < 0.001), whereas muscle scores could be predicted from fiber-optic probe measurements (r = 0.905, P < 0.01, using reflectance data at 520, 580 and 530 nm...

The organophosphate pesticide NUVAN, which is used widely in Europe to prevent salmon infestation by the sea lice Lepeoptheirus salmonis is suspected of inducing cataracts in salmon. The purpose of this study was to investigate the acute effects of NUVAN on the optical and biochemical properties of cultured. Atlantic salmon (Salmo salar) lenses. In...

A personal-interview survey was conducted to determine the frequency of and reasons for chemotherapeutic treatments on Ontario trout farms during 1990. Sixty-two farmers, producing 91 % of Ontario's farmed trout, participated in the survey. Farmers had most often received advice on treatments from other farmers. The number of treatment regimes admi...

Seasonal changes in ejaculate characteristics were monitored for groups of male rainbow trout (Salmo gairdneri) which were stripped weekly, beginning at various periods after the onset of the spermiation cycle. The duration of stripping varied from 14 to 28 weeks for the different groups, and the minimum duration of milt release was longer for grou...

This investigation evaluated the relationship between the motility of rainbow trout (Salmo gairdneri) spermatozoa and egg fertilization. When sperm:egg ratios were supraoptimal (i.e., >200,000 sperm per egg), neither spermatozoan motility, sperm density or spermatocrit were major factors in determining the percentage of eggs reaching the stage of e...

Thyroids from 213 adult herring gulls of both sexes were collected during incubation from nine colonies in the Great Lakes basin of eastern North America between 1974 and 1983, and from a single colony in the Bay of Fundy from 1977 to 1982. Qualitative and quantitative histological assessment revealed that the majority of the gulls from the Great L...

Severe kidney enlargement was observed in 6.3% (5 of 80) of goldfish collected from a heavily polluted industrial basin. Externally the fish had generalized swelling and abdominal distension. The kidneys contained numerous large, clear, fluid-filled cysts (polycystic) that ranged in size from microscopic to 4 cm in diameter. Affected kidneys had a...

Endoscopic techniques for visceral organ and ovarian examination of rainbow trout (Salmo gairdneri) are described. Internal organs can be readily identified and qualitatively assessed. It is possible to distinguish sex, and in the female, state of maturity can be identified, as well as some morphological characteristics of individual ova. Repeated...

Rainbow trout were fed for 24 weeks on practical diets containing varying concentrations of oxidized fish oil, with or without supplementation of vitamin E and ethoxyquin. Serum biochemistry, haematology and histopathology were investigated to measure the relative protection offered by vitamin E (DL––toco–pherol acetate) and/or a synthetic substitu...

During the past decade, semen cryopreservation techniques in salmonid fish have progressed to where fertilization rates obtained with preserved sperm approach those produced with fresh sperm. Recent advances in the collection, dilution and storage of salmonid spermatozoa are reviewed. The problems encountered during the development and examination...

Examination of 43 white perch from a heavily polluted water basin showed all had severe diffuse glomerulonephritis. There were fibrinoid necrosis of tuft vessels, especially the afferent and efferent arterioles, and thickened basement membranes which ultrastructurally contained dense deposits in a subendothelial location. None of these lesions was...

The blood clearance of ⁵¹ Cr-labelled heat-killed Salmonella pullorum was biphasic and exponential for each phase. This pattern was the same for all three concentrations of bacteria used. The initial more rapid phase lasted for approximately 15 minutes when roughly 90% of the bacteria had been cleared. The second slower phase started 25 to 30 minut...

1.1. Significant interlake differences were observed in body weight, gonadosomatic index (GSI), serum osmotic pressure and serum Na+, K+, Cl−1, Ca2+ and Mg2+ concentrations of prespawning potamodromous coho salmon (Oncorhynchus kisutch) collected from Lakes Ontario, Erie and Michigan.2.2. Highest body weight and GSI values were found in coho salmon...

Coho salmon (Oncorhynchus kisutch) and chinook salmon (Oncorhynchus tshawytscha) from Lakes Ontario, Michigan, Erie, or Huron were found to suffer epizootics of thyroid hyperplasia and goiters which appeared to have an environmental etiology. There were 13-fold differences in goiter prevalence within the Great Lakes, and the differences in goiter f...

One hundred forty Siamese fighting fish became inappetent and lethargic and developed swollen abdomens. One hundred fish died, many with perforated stomachs. Hexamitid parasites were found in large numbers in the abdominal cavity and in the mesentery and the parenchyma of the liver, spleen, and kidney, where they were closely associated with a chro...