Something fishy: Assessing stakeholder resilience to increasing jellyfish (Periphylla periphylla) in Trondheimsfjord, Norway

• An in-depth look at increased occurrences of the jellyfish Periphylla periphylla in the Trondheimsfjord, Norway.
• Mixing systems thinking and Bayesian Belief Networks in a workshop setting.
• Creating stakeholder driven scenarios as management tools.
• Discovering where the lines of conflict lie before the fact.
• Measures proposed could aid in helping solve these conflicts by building awareness.

The following article outlines of an assessment of the adaptive capacity of stakeholder groups in the Trondheimsfjord region to the impacts related to local changes in Periphylla periphylla (jellyfish) concentrations. This paper addresses the interaction between the socio-ecological system and the marine ecosystem and the management challenges inherent therein by focusing on a serious management problem that is occurring in several Norwegian fjords. This is the recent superabundance of the lower trophic level jellyfish species P. periphylla, which competes with commercial Norwegian fish species for a wide variety of pelagic organisms including redfeed (Calanus finmarchicus), a key species in the coastal ecosystem and a particularly important food item for all codfishes in coastal waters. P. periphylla has, however, also some properties that might make it a valuable new resource in Norwegian waters, namely its potential for being a new and abundant source of collagen. The question addressed here is how to manage this jellyfish species in a manner that is rational from both socio-political and ecological perspectives, exploring stakeholder perceptions concerning their adaptation options and capacity to implement these options to this new resource and management mitigation options based on a set of stakeholder driven future scenarios.