Management challenges from technological development in commercial fisheries

The major objective of this synthesis has been to throw light on how technological development in fisheries can complicate efforts to balance harvesting capacity and fish resources. The basis of achieving this objective has been the compilation of technological data from a selection of European fisheries, which cover some main principles of how technological development influences catch rates and fishing mortality. This work has been based largely on sociological approaches in the form of interviews with fishermen, gear manufacturers, ship yards, suppliers of electronic equipment, etc., as well as exploration of historical and commercial data from the same type of sources. That is, retrieval of technological data in very incompatible formats from a broad and heterogeneous set of sources and structuring the data in an operational manner. Building on this empirical material a bottom-up analytical framework embracing technical, economical, sociological and biological aspects was established, in which to understand the technological development in fisheries and its effects on the marine resources. Using this framework the concept of technological development was related to the main components and mechanisms of the European fisheries system. It was established i) how new fishing technology is developed in a bifurcated process of either radical or gradual nature, ii) how the speed and extent of technology spread is very uneven among the different vessel groups of the commercial fleet, iii) how catch increase is the main driver of technology uptake on board the vessels, iv) how this objective can be achieved through technologically mediated improvements of gear catchability, fish finding and navigation and effort utilisation at sea, and v) how both input and output oriented fisheries management is challenged by these bearings of technological development in commercial fisheries. The main message from this bottom-up approach was that irrespective of the management system in force technological development in commercial fisheries will take place with catch efficiency increases as the main driver and the main effect. Even though radical and gradual development of technology in fisheries is inevitable, and almost indifferent to the regulations in force, the sensitivity of the main management principles to the effects of technological development are far from uniform. This became evident as analyses of five European case study fleets demonstrated i) how technological development can complicate output control by adding uncertainty to standard stock assessment procedures, ii) how short-term input control (in terms of effort quotas) can be undermined by technologically induced efficiency increases, which decouple nominal effort from effective effort, and iii) how long-term input control (in terms of buy back schemes and other capacity control measures) are also undermined by efficiency changes from both temporal and structural technological development. The main shortcomings of both output and input oriented management strategies were explored further in relation to the undesired effects from technological development, as well as a multitude of other factors, which have been shown to influence catchability and the reliability of official catch and effort data (e.g. targeting behaviour, discards, high-grading, and environmental conditions). Following this exploration of advantages and disadvantages of the main type of management strategies available, the possibilities of integrating technological development to improve biological sustainability and achieve better agreement with policy objectives were identified and summarized as follows: i) The undesired effects of technological development are limited in output controlled fisheries and almost solely restricted to complicating the setting of appropriate TACs, if time series of commercial effort data are part of the underlying stock assessments. When this is the case, assessment procedures should be scrutinized for bias from efficiency trends on a regular basis and time series should be corrected accordingly. However, although insensitive to technological development, the inability of output control to cope with discards and misreporting are serious shortcomings, which in many fisheries have resulted in failure to meet management objectives. ii) In contrary, the undesired effects of technological development are comprehensive and difficult to counter in short-term input control systems (effort management). The problem of mismatch between nominal and effective effort can only be solved partly with improved descriptors and the remaining task of predicting and mitigating catchability trends in a system as complex as the commercial fishery is not feasible on a broad basis. Other factors such as targeting behaviour and skipper skills can also contribute substantially to a decoupling of nominal effort from effective effort and with that a mismatch between intended and realized fishing mortality. A great advantage of direct effort control as sole regulation in force is that it gives very little incentive to discard or misreport. iii) Fishing power increases from technological development also substantially undermine long-term input control (capacity management), but counteracting these effects with improved capacity descriptors and long-term efficiency projections by major vessel groups is relatively straight forward. However, the long-term perspective of capacity management does not fit well with the changeable character of biological systems, for which reason supplementing short-term regulations (i.e. elements of (i) or (ii) above) are required. Consequently, integration of technological development in fisheries management - and of other factors undermining policy objectives - is not a question of either input or output control, but of understanding the complexity of the fisheries system and of tailor making solutions from the mixed input and output regulation toolbox on as fine a scale as possible

Mortality in organic free-range chickens and molecular characterization of the involved pathogens

Longitudinal investigations on causes of mortality were carried out at one organic layer farm with four flocks of Lohman Brown and Lohman White chickens producing table eggs. All flocks were housed separately. One flock of each breed were followed from September 2001 to August 2002. Post mortem examinations were performed on a total of 16% of the dead chickens over the entire period. Of these 346 (96%) of the Lohmann Brown and 315 (91%) of the Lohmann White chickens were subjected for bacteriology. High mortality rates, 91% and 63% were observed in Lohman Brown and Lohman White chickens, respectively and were found to be due to infections with mainly Pasteurella multocida, Erysipelothix rhusiopathia and Escherichia coli. E. rhusiopathia, P. multocida and E. coli were isolated from 46%, 19% and 17%, respectively of the Lohmann Brown chickens. In the flock of Lohmann White chickens P. multocida and E. coli were isolated from 46% and 15%, respectively while E. rhusiopathia was not recorded. P. multocida and E. rhusiopathia isolates were characterized by Restriction Endonuclease Analysis (REA), Restriction Fragment Length Polymorphism (RFLP) and Pulse Field Gel Electrophoresis (PFGE). It was demonstrated that all the P. multocida isolates were genotypic identical over time. The E. rhusiopathia isolates obtained were also identical. It was concluded that the outbreaks caused by P. multocida and E. rhusiopathia were clonal and these two pathogens may cause severe losses in free-range chickens

Sygdomme og velfærd

Siden anden verdenskrig er der sket store ændringer i fjerkræproduktionen. Indførslen af nye produktionssystemer, robuste og højtydende dyr, forbedret management og indførslen af biosecurity har medført en stor produktionsfremgang med lav mortalitet. I de senere år har forbrugerønsker medført at udvikling af udendørs produktionssystemer, hvor de klassiske fjerkræsygdomme nu er på fremmarch med en forhøjet mortalitet til følge. Forfatterne diskuterer, om de udendørs produktionssystemer reelt har betydet en forbedret velfærd for hønerne