eprintid: 13447 rev_number: 7 eprint_status: archive userid: 353 dir: disk0/00/01/34/47 datestamp: 2016-07-28 11:23:46 lastmod: 2021-08-27 17:41:19 status_changed: 2016-07-28 11:23:46 type: article metadata_visibility: show item_issues_count: 1 creators_name: Röckmann, C. creators_name: St. John, M.A. creators_name: Schneider, U.A. creators_name: Tol, R.S.J. creators_id: AL1742 title: Testing the implications of a permanent or seasonal marine reserve on the population dynamics of Eastern Baltic cod under varying environmental conditions ispublished: pub keywords: Age-structured model; Baltic cod; Environmental variability; Management; MPA; Population dynamics; Reproductive volume abstract: A spatially disaggregated, discrete time, age-structured model for the Eastern Baltic cod (Gadus morhua callarias L.) stock was constructed, in order to test the implications of the establishment of a marine reserve in the Baltic Sea. Functional relationships for recruitment and predation mortality were developed by multiple regression analyses. The resultant model output compares well with observed data from the fishery. The model was then applied to simulate stock development over a 50 year time period using different management policies and a variety of environmental conditions. The investigated management policies reduce fishing mortality and range from a moratorium on the Eastern Baltic cod fishery via the establishment of a permanent or a seasonal marine reserve in ICES subdivision 25 to a fishing as usual scenario. The environmental conditions incorporated were based on the size of the reproductive volume (RV) and comprise a best case and a worst case of reproductive conditions, and two more realistic scenarios, where we assumed that a historic series of RV-sizes reoccurs over the simulation period. Our results show a strong dependence of stock dynamics on the environmental conditions. Under prevailing low RV, our model projects stock extinction by the year 2020, if fishing continues as usual. Under the restrictive scenarios, where fishing mortality is reduced either directly or by implementation of a marine reserve, the stock benefits from an increase in stock size and an improved age structure. A seasonal closure of subdivision (SD) 25 as opposed to a closure of the entire Baltic Sea appears to be sufficient to prevent the Eastern Baltic cod stock from falling below safe biological limits. date: 2007-06 date_type: published id_number: 10.1016/j.fishres.2006.11.035 creators_browse_id: 2857 full_text_status: none publication: Fisheries Research volume: 85 number: 1-2 pagerange: 1-13 refereed: TRUE issn: 01657836 coversheets_dirty: FALSE fp7_project: no fp7_type: info:eu-repo/semantics/article citation: Röckmann, C., St. John, M.A., Schneider, U.A. , & Tol, R.S.J. (2007). Testing the implications of a permanent or seasonal marine reserve on the population dynamics of Eastern Baltic cod under varying environmental conditions. Fisheries Research 85 (1-2) 1-13. 10.1016/j.fishres.2006.11.035 .