Differential responses of Nile tilapia (Oreochromis niloticus) to fin clip wounding and related stress: perspectives

The debate around fish welfare is intensifying in The Netherlands. As a result, more research is carried out to enhance knowledge on fish welfare in aquaculture. Detailed information is lacking on how production procedures causing discomfort to the fish may affect welfare. That fish must perceive adversive stimuli follows from the fact that nociceptive mechanisms similar to those in mammals are present in fish. However, whether and how nociceptive stimuli are perceived or interpreted by a fish is a far more difficult question that requires significantly more effort from fundamental research, both neurophysiological and behavioural studies, than now available. The study presented in this report aimed to define selected readout for the acute response to a supposedly painful stimulus: a standardised tailfin clip to a common carp. In conclusion, we succeeded to demonstrate differential, stronger responses to a presumed painful stimulus than to the handling stress per se associated with the administration of the pain stimulus. These parameters will be the focus of future research within this welfare project

Disaster, Relief and Political Change in Southern Ethiopia: Developments from within Suri Society

This chapter describes responses to the ecological crisis and political changes in Ethiopia in the early 1990s among the Suri, an agropastoral group in K„fa Region, southern Ethiopia. Data are derived from fieldwork carried out in the area after the change of regime in 1991. Attention is paid to environmental conditions and the Suri subsistence system, relations between the Suri and neighbouring ethnic groups, drought and famine in the area, in particular in the 1980s, and the Suri attitude towards the interventions of outside agencies, interethnic conflict in the period 1984-1993, Suri recovery and adaptation in the early 1990s, and the effects of drought, famine, and political upheaval on Suri socioeconomic organization, local political relations, and ethnic identities and interethnic relations. Bibliogr., notes, refASC – Publicaties niet-programma gebonde

Fork naar Farm. deelrapport: experimentele kweek van yellowtail kingfish (Seriola lalandi) en de implementatie hiervan

In Nederland is sprake van een toenemende vraag naar duurzaam en lokaal geproduceerde vis. Het doel van het Fork naar Farm project was het begeleiden van de productie van een nieuwe vissoort binnen de Nederlandse viskweeksector en Afrikaanse meerval volgens een certificeringsschema waarin duurzaamheid een rol speelt. Binnen het kader van het Fork naar Farm project behandelt dit rapport het onderzoek naar de opkweek van de yellowtail kingfish (Seriola lalandi) in recirculatiesystemen en de implementatie hiervan in de praktijk. Er zijn verschillende groepen jonge yellowtail kingfish met een gewicht van ongeveer 0,5 gram aangekocht vanuit Australië en in Nederland opgekweekt in recirculatiesystemen. Er is in de faciliteiten van IMARES Wageningen UR onderzoek verricht naar diverse houderijomstandigheden: temperatuur, pH en saliniteit van het water en het voer

Het effect van ammoniak op voer-opname, groei en fysiologie van Afrikaanse meerval

IMARES heeft in 2008 een inventarisatie uitgevoerd van de de waterkwaliteit in meervalkwekerijen. Om in te schatten of er sprake is van niet optimale waterkwaliteit zijn de meetresultaten vergeleken met literatuurgegevens. Hieruit bleek dat er over het effect van ammoniak op meerval onvoldoende bekend is om goed in te kunnen schatten of de soms hoge concentraties in het water slecht zijn voor de groei en het welzijn van de vissen. Daarom is een experiment opgezet om het effect van ammoniakconcentratie in het kweekwater voor Afrikaanse meerval vast te stelle

Decision support for crew rostering at NS

This paper describes a method for solving the cyclic crew rostering problem (CCRP). This is the problem of cyclically ordering a set of duties for a number of crew members, such that several complex constraints are satisfied and such that the quality of the obtained roster is as high as possible. The described method was tested on a number of instances of NS, the largest operator of passenger trains in the Netherlands. These instances involve the generation of rosters for groups of train drivers or conductors of NS. The tests show that high quality solutions for practical instances of the CCRP can be generated in an acceptable amount of computing time. Finally, we describe an experiment where we constructed rosters in an automatic way for a group of conductors. They preferred our—generated—rosters over their own manually constructed rosters

The Benefish consortium reports on the influence of system water refreshment rates on realized feed load, weight development, fish physiology and behaviour in turbot

Farmers with recirculation aquaculture systems (RAS) have a greater necessity and capacity to control the culture conditions of their farms than farmers with other aquaculture systems. Water quality is one of the factors that is closely monitored and managed in order to maintain the optimal levels of oxygen, ammonia, temperature, pH, and CO2. Effects of these parameters on growth and health are well studied and almost immediately noticeable. In RAS it often occurs that, although water quality conditions seem to be optimal, the feed intake of the fish might suddenly diminishes, thus reflecting a situation of sub optimal welfare of the animals. This phenomenon is particular relevant in marine RAS where these situations of reduced feed intake occur even though the normally monitored water quality parameters and husbandry conditions appear to be optimal. Similar phenomena also occur in other aquaculture culture systems, such as flow through systems, where feed intake fluctuates whilst the reasons are not always known, although there is typically less control and monitoring compared with RAS. It is therefore necessary to actively monitor deviation of expected feed intake, in combination with the monitoring of culture conditions and farm management on pilot-scale level. Only through this intermediate level experimental work and farm observations for the assumed relationship between deviation of expected feed intake and fish welfare can be validated. It is furthermore necessary to provide refinements to causative relationships expected to be found on commercial farms, where it is often claimed that e.g. lower system water refreshment rates or more closed RAS are leading to growth retardation and lower feed intake in fish and thus lower production. The present study is, therefore, intending to prove the hypothesis that changes in feed intake can be associated with changed fish welfare status, using turbot as model species. It is furthermore hypothesized that this changed fish welfare status is caused by different system water refreshment rates and fish and system management. As a final result, feed intake should relate by same efficiency to lower fish growth in closed RAS compared to flow through systems. The objectives are therefore to validate the relationships between deviation from expected feed intake and fish welfare, and their causative factors on the commercial farms interpreting data on feed intake, behavior, endocrinology and immune patterns as welfare indicators

Het effect van ammoniak op voer-opname, groei en fysiologie van Afrikaanse meerval

IMARES heeft in 2008 een inventarisatie uitgevoerd van de de waterkwaliteit in meervalkwekerijen. Om in te schatten of er sprake is van niet optimale waterkwaliteit zijn de meetresultaten vergeleken met literatuurgegevens. Hieruit bleek dat er over het effect van ammoniak op meerval onvoldoende bekend is om goed in te kunnen schatten of de soms hoge concentraties in het water slecht zijn voor de groei en het welzijn van de vissen. Daarom is een experiment opgezet om het effect van ammoniakconcentratie in het kweekwater voor Afrikaanse meerval vast te stelle

Yellowtail Kingfish: toetsing van een familie voor plaatsing op de lijst voor productie te houden dieren

Op de ‘lijst voor productie te houden dieren’, samengesteld als onderdeel van de Gezondheids- en welzijnswet voor dieren (GWWD), staan individuele vissoorten die aan de voorwaarden hebben voldaan om voor productie gehouden te worden. Deze voorwaarden op het gebied van houderijomstandigheden, ziektes en welzijn zijn samengesteld in het document ‘Handleiding Gezondheids- en welzijnswet voor dieren (GWWD) Voor Aquacultuur in Nederland’. Op deze lijst staan ook de genera Seriola (yellowtail kingfish), Acipenser (steur) en Oreochromis (tilapia). Dit zijn genera die op basis van onderzoek naar een enkele soort binnen het genus als groep op de lijst te houden diersoorten zijn gekomen

Real-time train driver rescheduling by actor-agent techniques

Passenger railway operations are based on an extensive planning process for generating the timetable, the rolling stock circulation, and the crew duties for train drivers and conductors. In particular, crew scheduling is a complex process. After the planning process has been completed, the plans are carried out in the real-time operations. Preferably, the plans are carried out as scheduled. However, in case of delays of trains or large disruptions of the railway system, the timetable, the rolling stock circulation and the crew duties may not be feasible anymore and must be rescheduled. This paper presents a method based on multi-agent techniques to solve the train driver rescheduling problem in case of a large disruption. It assumes that the timetable and the rolling stock have been rescheduled already based on an incident scenario. In the crew rescheduling model, each train driver is represented by a driver-agent. A driver-agent whose duty has become infeasible by the disruption starts a recursive task exchange process with the other driver-agents in order to solve this infeasibility. The task exchange process is supported by a route-analyzer-agent, which determines whether a proposed task exchange is feasible, conditionally feasible, or not feasible. The task exchange process is guided by several cost parameters, and the aim is to find a feasible set of duties at minimal total cost. The train driver rescheduling method was tested on several realistic disruption instances of Netherlands Railways (NS), the main operator of passenger trains in the Netherlands. In general the rescheduling method finds an appropriate set of rescheduled duties in a short amount of time. This research was carried out in close cooperation by NS and the D-CIS Lab

Deskstudie Bedrijfsverzamelgebouw voor Aquacultuur

Stichting ZIGZAG heeft de indruk dat er in Zeeland behoefte is aan een bedrijfsverzamelgebouw voor aquacultuur. Het voormalige mijnendepot in Veere is als gebouw beschikbaar om deze functie te vervullen, en is qua ligging en vormgeving geschikt. Het doel van deze studie is een beeld te geven van de mogelijke inrichting en de kosten voor diverse aquacultuur teeltvormen in het gebouw. Daarnaast om aan te geven of de waterkwaliteit rondom het beoogde complex hiervoor geschikt is