
Sunil KadriCharles Darwin University | CDU · Research Institute for the Environment and Livelihoods
Sunil Kadri
Doctor of Philosophy
Tropical Aquaculture Research
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57
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Publications (57)
How digital technologies-including cloud computing, the internet of things, artificial intelligence and machine learning-are facilitating the advance of precision aquaculture. In the past few decades, the digital revolution has completely changed the way the world acquires and processes data, as well as how it communicates and interprets informatio...
This book contains 15 chapters on biological limits of domestic animals. Topics discuses are: use new genetic technologies and animal breeding methods carefully to avoid problems (introduction); domestication to Dolly and beyond (a brief history of animal modification); good for whom (differences between human and animal enhancement); working equid...
Common carp Cyprinus carpio displaying proactive or reactive stress coping styles were acclimated to two environmental regimes (low oxygen and low temperature), and selected groups were tested for response to an inflammatory challenge (Escherichia coli lipopolysaccharide, LPS). Plasma glucose and lactate levels were measured, as were selected C. ca...
As currently practised, the culture of fish for food potentially raises concerns about the welfare of farmed fish, and this is a topic that has received considerable attention. As vertebrates, fish share a number of features with the birds and mammals that are more commonly farmed, so many welfare principles derived from consideration of these grou...
In this chapter we speculate about possible links between exercise and welfare in fish, drawing on the extensive mammalian literature on this topic. We summarise briefly some of the many studies reporting beneficial effects of sustained swimming, including faster growth, better feed conversion efficiency and lower plasma cortisol concentrations. Wh...
This article summarizes the framework that translated data from multiple disciplines into a bio-economic decision tool for modeling the costs and benefits of improving fish welfare in commercial aquaculture. This decision tool formed the basis of a recent EU research project, BENEFISH which was funded via the European Commission's Sixth Framework (...
Actions that aim to improve animal welfare are likely to involve costs for the producer, although at the same time such actions may improve the profitability of production. In this article we introduce a quantitative bio-economical approach for estimating the economic consequences for improving animal welfare in the aquaculture industry; for farmer...
Fin damage can be common in farmed juvenile Atlantic salmon and is both directly harmful to the welfare of the fish and a potential sign of poor rearing conditions. Fin damage can be reduced during freshwater production by the use of feeding systems that deliver food in accordance with the fish's current appetite, rather than at fixed times. The bi...
IntroductionMechanismsDevelopmentFunctionsImplications for aquacultureSynopsisReferences
Modern aquaculture is faced with a number of challenges, including public concern about environmental impacts and the welfare of farmed fish. A fundamental understanding of fish biology is central to finding ways to meet these challenges and is also essential for maintaining the industry's sustainability. Furthermore, the behaviour of fish under cu...
Introduction to the feeding biology of fishesForaging strategies of wild fishMechanismsDevelopmentFunctionsImplications for aquacultureSynopsisReferences
Introduction to what fish eatMechanismsDevelopmentFunctionsImplications for aquacultureSynopsisReferences
IntroductionDescribing and measuring behaviourWhat we need to know about the behaviour of farmed fishIndirect reconstruction of the behaviour of cultured fishMethods of marking and tagging fishDirect behavioural observation via video monitoringDirect behavioural monitoring using electronic tagsDirect behavioural monitoring using echo integrationMea...
The productivity and welfare benefits of sustained swimming in fish are well documented, but are not yet exploited in commercial aquaculture. We report here on a study designed to test the feasibility of inducing sustained exercise in Atlantic salmon (Salmo salar L.) using a novel lighting device that provides an apparently moving light pattern. It...
Individual common carp Cyprinus carpio were screened repeatedly for risk taking (rate of exploration of a novel, potentially dangerous environment) and for competitive ability (success in gaining access to a spatially restricted food source). Marked differences in behaviour were evident, and significant consistency in individual responses across tr...
There is increasing agreement in Europe that a high level of animal welfare, including fish welfare, is an ethical value that can be regarded as a public good. Improved welfare will often however involve extra costs for fish farmers, whereas economic benefits may be less visible. The BENEFISH project has developed a bio-economic model, which provid...
This paper explores the possibility that lessons learned from aquaculture might contribute to current debate on welfare and fisheries. After looking briefly at the history of research interest in the welfare of farmed fishes, some implications of using different definitions of and approaches to the concept of welfare are discussed. Consideration is...
How can stakeholders within the fisheries community engage in constructive ethical discussions? Drawing on experiences from previous debates surrounding the human use of animals, this paper presents a proactive approach whereby stakeholders can create a framework for ethical discussion of capture fisheries.
Background
Individuals of many vertebrate species show different stress coping styles and these have a striking influence on how gene expression shifts in response to a variety of challenges.
Principal Findings
This is clearly illustrated by a study in which common carp displaying behavioural predictors of different coping styles (characterised by...
Intensive finfish aquaculture has undergone exponential growth over the past two decades, particularly in Europe, Canada and
Chile. This growth has been accompanied by many supporting technological advances and innovations, some of which allow fish
to be grown at higher stocking densities (e.g. aeration systems), and others which provide for growin...
BENEFISH is a research project funded under the European Commission Sixth Framework initiative. It aims to develop bio-economic models that establish the effects of welfare actions (i.e. measures taken to safeguard welfare) on value chains within the European aquaculture industry, including both production related elements such as growth and feed e...
Monitoring social interactions between individuals in large, high-density groups poses several challenges. Here we demonstrate that relative concentrations of serotonin (5-Hydroxytryptamine, 5-HT) and its principal catabolite 5-Hydroxyindoleacetic acid (5-HIAA) in brain tissue of individual fish reflect social organisation in large groups of farmed...
This experiment investigated the impact of feeding regime upon the growth performance, production efficiency and fin damage of cage-held 0+ Atlantic salmon pre-smolts. Six groups of pre-smolts (n= 61847 +/- 2620 fish group(-1)) were held in six 12 x 12 x 4 in production cages for 64 days (23rd August until 26th October) at initial and final densiti...
IntroductionFeed planning and production plansEstimating growthVariation in feed intakeDistribution of feedFeeding techniques
This chapter contains section titled:
The diurnal feeding rhythms of cage-held Atlantic salmon parr were studied when fish were held for 205 days (September 2nd until 26th of March) under ambient daylength (8.42–15.25 h) and water temperature (4.5–15.25 °C) in commercial freshwater cages (576 m3: 12 m × 12 m × 4 m). The influence of environmental factors (daylength, change in daylength...
The welfare of fish is a topic of increasing debate touching on a number of complex scientific and ethical issues and constructive dialogue between groups with differing approaches to the topic requires mutual understanding from both perspectives. In a recent review aimed at stimulating debate on this topic, Arlinghaus et al. (2007) explore the que...
Abstract The feeding behaviour, growth and feed conversion ratio (FCR) of cage-held Atlantic salmon parr (Salmo salar L.) were studied when in 576 m3 (12 m × 12 m × 4 m) commercial freshwater cages under ambient water temperature (8.84±3.53°C) and photoperiod (11.02±2.05 h) for 205 days. The effect of feeding regime on fin damage was also investiga...
There has been a great deal of debate and sometimes open hostility between people with differing approaches to the welfare of farmed animals, but relatively little progress towards compromise or consensus. It has been suggested that progress has been inhibited by a fundamental lack of common ground; people are debating different questions. Compromi...
Human beings may affect the welfare of fish through fisheries, aquaculture and a number of other activities. There is no agreement on just how to weigh the concern for welfare of fish against the human interests involved, but ethical frameworks exist that suggest how this might be approached.
Different definitions of animal welfare focus on an anim...
Previous studies of feeding rhythms in post-smolt Atlantic salmon Salmo salar have produced variable results. Therefore, the present study was performed to clarify the source of these differences and to examine size-related variation in daily feeding patterns. A small group of hatchery reared post-smolts was kept in an indoor seawater tank under co...
Daily feeding patterns of tank-reared Atlantic salmon Salmo salar parr under ambient conditions and their relationship with patterns of aggression were investigated during spring and autumn. A single, early afternoon feeding peak was observed during spring but no consistent pattern emerged from the autumn trial (fish did tend to feed in synchrony,...
The aims of this study were to determine whether growth, feed handling and feeding efficiency of gilthead sea bream (Sparus aurata) changed in response to imposed competition levels, manipulated by altering ration and feed delivery rate, and to investigate the effect of feed handling on feed conversion efficiency. Triplicate tanks of bream (32 g, 1...
Many fish species have evolved feeding mechanisms and behaviours enabling them to feed on specific prey. However, such mechanisms may not be optimal for feeding on commercial-pelleted diets in aquaculture. Gilthead sea bream chew and occasionally eject pellets or parts of pellets from the mouth when feeding on commercial diets. This may result in a...
Using underwater cameras, data were collected on the feeding behaviour and swimming speeds of Atlantic salmon Salmo salar L., gilthead sea bream Sparus aurata L. and European sea bass Dicentrarchus labrax L. in sea cages. Comparisons were made between the behaviours of fish fed on demand using interactive feedback systems and those of fish fed unde...
Atlantic salmon, Salmo salar L., in sea cages exhibit feeding patterns that vary both diurnally and seasonally. Hitherto, there are no data reporting feed rate and its variation through a complete annual cycle. Here we present data from Scotland showing diurnal and interseasonal variation in feeding patterns and feeding rates of Atlantic salmon fed...
During a period of temperature increase from 8.8 to 11.2 °C from May to August, maturing one-sea-winter Atlantic salmon showed decreasing appetite from early June, to little or no food intake by early July. In contrast, non-maturing siblings increased food intake steadily from early June throughout the period. The number of anorexic maturing fish i...
Early separation of maturing from immature fish would be very valuable in Atlantic salmon (Salmo salar) culture. Possible morphometric predictors of maturation in one sea-winter Atlantic salmon were investigated from measurements
of body weight, length and depth and adipose fin length undertaken at 14 day intervals from May until August in a popula...
Maturing Atlantic salmon first accumulate nutrient reserves and then cease feeding in the spring/summer prior to spawning. Here we examine patterns of feeding behaviour and reserve accumulation in maturing and immature fish of the same age from the onset of the maturation cycle (autumn) to the onset of anorexia (summer). Two hundred one-sea-winter...
In order to test whether the amount of food obtained by individual one-sea-winter Atlantic salmon was related to social status, the feeding interactions of 19 individually marked Atlantic salmon in a sea cage were monitored by underwater video (fish competed for single food pellets presented at regular intervals). Food was distributed unevenly amon...
1. Atlantic Salmon (Salmo salar) cease feeding before entering their home river to undertake upriver migration and spawning. Here we examine whether the onset of this anorexia is related to body condition and/or gonad development. 2. The food intake and growth rate of 100 individually marked one-sea-winter fish (stocked in an outdoor tank) were mon...
The diurnal and seasonal variation in behavioural indices of appetite in one-sea-winter Atlantic salmon in a sea cage was investigated in relation to environmental variables and fish swimming activity, from autumn to spring. There was marked seasonal variation in feeding behaviour, indicating a reduction in appetite from autumn to winter and a rapi...
The swimming activity and feeding behaviour of 1-kg one-sea-winter Atlantic salmon were investigated in a production sea cage during June–July 1989. The fish were fed at feed manufacturers' recommended rates using automated feeders that dispensed food regularly throughout the daylight hours. The routine swimming speed of the fish and the number of...