IMIS

Publications | Institutes | Persons | Datasets | Projects | Maps
[ report an error in this record ]basket (0): add | show Print this page

Setting fish quotas based on holistic ecosystem modelling including environmental factors and foodweb interactions: a new approach
Håkanson, L.; Gyllenhammar, A. (2005). Setting fish quotas based on holistic ecosystem modelling including environmental factors and foodweb interactions: a new approach. Aquat. Ecol. 39(3): 325-351. http://dx.doi.org/10.1007/s10452-005-3418-x
In: Aquatic Ecology. Springer: Dordrecht; London; Boston. ISSN 1386-2588; e-ISSN 1573-5125, more
Peer reviewed article  

Available in  Authors 

Keywords
    Fauna > Aquatic organisms > Aquatic animals > Fish
    Food webs
    Modelling
    Recovery
    ANE, Baltic [Marine Regions]
    Marine/Coastal
Author keywords
    aquatic systems; Baltic; fish production; fish quota; foodweb modelling;recovery; thresholds

Authors  Top 
  • Håkanson, L.
  • Gyllenhammar, A.

Abstract
    We present a new approach to set fish quotas from holistic aquatic foodweb modelling (the LakeWeb-approach). This modelling includes changes in environmental conditions (nutrients, salinity, temperature, oxygen), process-based mass-balance calculations of nutrient concentrations from inflow, internal processes and outflow, calculations of how changes in nutrient concentrations affect primary production, how such changes influence secondary production and how this influence fish production and biomass. This approach gives dynamic, quantitative responses to alterations in driving variables and abiotic/biotic feedbacks. We have applied this approach for preliminary simulations of the cod biomass in the Baltic. We also show that this approach adds a new dimension in setting fish quotas, which in the future could complement, rather than compete with, the more established methods used today based on fish catch statistics and models based on other presuppositions. Our preliminary results indicate that under present environmental conditions (2003), the cod is likely to be extinct if the annual catch is between 95 and 100 kt. The present fish quota is 75 kt/yr in the Baltic, but the overfishing may be 35 kt/yr. We discuss cause–effect relationships regulating fish production, key factors influencing thresholds and points of no return connected to overfishing and changes in environmental conditions, factors regulating recovery and methods for setting optimal fish quotas using this modelling approach.

All data in the Integrated Marine Information System (IMIS) is subject to the VLIZ privacy policy Top | Authors