Where could catch shares prevent stock collapse?

In a widely received study (Science 321: 1678–1681) Costello and his colleagues found that catch shares give better stock persistence and higher catch for fishermen. The conclusions made by Costello et al were further being supported by Grafton and McIlgrom (Marine Policy 33: 714– 719) where they suggested a framework in order to determine the costs and benefits of separate ITQ management in seven Australian commonwealth fisheries, and what the alternatives should be if the net benefits do not justify ITQs. This raises the question why we do not see catch shares being used more often. We explore at a global scale which countries would have the potential for – and indeed do fulfil the conditions necessary to implement such a management strategy

Climatic effects filtered through the food web affect the dynamics of Arcto-Norwegian cod

The world's largest cod stock, the Arcto-Norwegian cod (a.k.a. North-East Arctic cod), is heavily influenced by temperature in two ways: First, cod recruitment tends to be high when Barents Sea temperature in the spawning year is high. Secondly, there is a more indirect effect of climate via herring and capelin: Warm conditions increase the chance of high recruitment of Norwegian Spring-spawning herring; 1-2 year old herring eat 0-year old capelin; and cod cannibalism increases when the biomass of 1-4 year old capelin is low. While these relationships have been shown separately and for the later years, we develop and parameterize models for the effects of herring (via capelin) and temperature on cod recruitment at age 3, using data from 1973 until present. Using data on cod, herring and temperature back to 1921 to verify the model,we find a significant relationship between predictions and data back to the 1950s, but before this, the predicted time-series pattern is not observed in the data

Alpha managers - an advantage or disadvantage for the organization

The role of the manager is crucial to the organization. Managers set goals, develop strategies and define tasks of workers, create environment for the development of people and give meaning to their activities. Professional skills are of vital importance to manager’s success. These very skills are the distinguishing characteristics of alpha managers. The aim of the following paper is to present some of the most established ideas in the field of leadership styles, to compare them with the concept of alpha managers and draw some conclusions important to management

The Economic Repercussions of Fisheries-induced Evolution

Human-induced changes in life-history traits have been observed for many harvested populations, with a component of those changes being attributed to an evolutionary (i.e., genetic) response. Most notably, fish stocks that experience high fishing mortality show a tendency to mature earlier and at a smaller size. Some have suggested that fisheries-induced evolution could affect the fishery’s yield and therefore have economic repercussions for society. Yet, this has not been formally investigated. We use data from 1932 to 2005 to develop a bio-economic model specifically for Northeast Arctic cod that allows us to compare the economic yield in scenarios with and without evolution of key life-history traits. We also compare a “business as usual” scenario where fishing continues at its current pace, with a scenario in which harvest is controlled through an optimal control rule. Our model predicts that fisheries-induced evolution decreases economic yield if fishing mortality rates continue at their current high levels. We also find that maximum economic yield is achieved at a considerably lower fishing mortality than what the stock has historically experienced. At this lower mortality, fisheries-induced evolution is less pronounced and actually increases the spawning stock biomass and economic yield. Overall, we find that evolutionary and non-evolutionary models recommend similar harvesting rates and the overriding message is that higher economic yield can be obtained by lower harvest rates irrespective of whether evolution occurs or not

The mechanics of blue growth: Management of oceanic natural resource use with multiple, interacting sectors

Publisher's version (útgefin grein)Integrated management of multiple economic sectors is a central tenet of blue growth and socially optimal use of ocean-based natural resources, but the mechanisms of implementation remain poorly understood. In this review, we explore the challenges and opportunities of multi-sector management. We describe the roles of key existing sectors (fisheries, transportation, and offshore hydrocarbon) and emerging sectors (aquaculture, tourism, and seabed mining) and the likely synergistic and antagonistic inter-sector interactions. We then review methods to help characterize and quantify interactions and decision-support tools to help managers balance and optimize around interactions.This work is a deliverable of the project Green Growth Based on Marine Resources: Ecological and Socio-Economic Constraints (GreenMAR), which is funded by Nordforsk. We would also like to acknowledge the National Science Foundation grant GEO-1211972.Peer Reviewe

Genomic stability through time despite decades of exploitation in cod on both sides of the Atlantic

The mode and extent of rapid evolution and genomic change in response to human harvesting are key conservation issues. Although experiments and models have shown a high potential for both genetic and phenotypic change in response to fishing, empirical examples of genetic responses in wild populations are rare. Here, we compare whole-genome sequence data of Atlantic cod (Gadus morhua) that were collected before (early 20th century) and after (early 21st century) periods of intensive exploitation and rapid decline in the age of maturation from two geographically distinct populations in Newfoundland, Canada, and the northeast Arctic, Norway. Our temporal, genome-wide analyses of 346,290 loci show no substantial loss of genetic diversity and high effective population sizes. Moreover, we do not find distinct signals of strong selective sweeps anywhere in the genome, although we cannot rule out the possibility of highly polygenic evolution. Our observations suggest that phenotypic change in these populations is not constrained by irreversible loss of genomic variation and thus imply that former traits could be reestablished with demographic recovery.publishedVersio

Can fisheries-induced evolution shift reference points for fisheries management?

Heino, M., Baulier, L., Boukal, D. S., Ernande, B., Johnston, F. D., Mollet, F. M., Pardoe, H., Therkildsen, N. O., Uusi-Heikkilä, S., Vainikka, A., Arlinghaus, R., Dankel, D. J., Dunlop, E. S., Eikeset, A. M., Enberg, K., Engelhard G. H., Jørgensen, C., Laugen, A. T., Matsumura, S., Nusslé, S., Urbach, D., Whitlock, R., Rijnsdorp, A. D., and Dieckmann, U. 2013. Can fisheries-induced evolution shift reference points for fisheries management? - ICES Journal of Marine Science, 70: 707-721. Biological reference points are important tools for fisheries management. Reference points are not static, but may change when a population's environment or the population itself changes. Fisheries-induced evolution is one mechanism that can alter population characteristics, leading to "shifting” reference points by modifying the underlying biological processes or by changing the perception of a fishery system. The former causes changes in "true” reference points, whereas the latter is caused by changes in the yardsticks used to quantify a system's status. Unaccounted shifts of either kind imply that reference points gradually lose their intended meaning. This can lead to increased precaution, which is safe, but potentially costly. Shifts can also occur in more perilous directions, such that actual risks are greater than anticipated. Our qualitative analysis suggests that all commonly used reference points are susceptible to shifting through fisheries-induced evolution, including the limit and "precautionary” reference points for spawning-stock biomass, Blim and Bpa, and the target reference point for fishing mortality, F0.1. Our findings call for increased awareness of fisheries-induced changes and highlight the value of always basing reference points on adequately updated information, to capture all changes in the biological processes that drive fish population dynamic

Can fisheries-induced evolution shift reference points for fisheries management?

Biological reference points are important tools for fisheries management. Reference points are not static, butmay change when a population's environment or the population itself changes. Fisheries-induced evolution is one mechanism that can alter population characteristics, leading to "shifting" reference points by modifying the underlying biological processes or by changing the perception of a fishery system. The former causes changes in "true" reference points, whereas the latter is caused by changes in the yardsticks used to quantify a system's status. Unaccounted shifts of either kind imply that reference points gradually lose their intended meaning. This can lead to increased precaution, which is safe, but potentially costly. Shifts can also occur in more perilous directions, such that actual risks are greater than anticipated. Our qualitative analysis suggests that all commonly used reference points are susceptible to shifting through fisheries-induced evolution, including the limit and "precautionary" reference points for spawning-stock biomass, B-lim and B-pa, and the target reference point for fishing mortality, F-0.1. Our findings call for increased awareness of fisheries-induced changes and highlight the value of always basing reference points on adequately updated information, to capture all changes in the biological processes that drive fish population dynamics