ECOLUMP: Characterizing the migratory strategies of Atlantic lumpfish to improve stock assessment of this commercially important species

Funding agency: The Research Council of Norway, Oceans Program, Researcher Project for Scientific Renewal
Project period: 2023-2028
Project leader: Caroline Durif, with Co-PIs Anne Berit Skiftesvik, Alessandro Cresci, Howard Browman +++

Project summary

The overall goal of ECOLUMP is to characterise potential subpopulations or ecotypes (hereafter only referred to as ecotypes) corresponding to different migratory strategies. To achieve this, we have outlined the following specific objectives (SO):

SO 1) Map the genome-level divergence of lumpfish in Norway and identify genomic regions separating the ecotypes, and the Norwegian lumpfish from the Icelandic ones
SO 2) Characterize the life-history traits of the “ocean migratory” and “fjord resident” ecotypes
SO 3) Develop a non-lethal biopsy method to determine individual ecotypes
SO 4) Validate ageing techniques for lumpfish
SO 4) Integrate this new knowledge into lumpfish stock assessment and design a roadmap toward a common lumpfish assessment between Iceland and Norway to understand the origins and dynamics of lumpfish found in the Norwegian Sea.

The main impediment to stock assessment and management of Atlantic lumpfish comes from the lack of knowledge concerning its population structure and migration patterns. Lumpfish sustains two types of fisheries: one targeting females for their roe, the other targeting mature individuals to produce cleaner fish for salmon aquaculture. Studies on lumpfish population genetics so far have been somewhat contradictory. Some have shown little to no structure along the Norwegian coast, while others have revealed clear genetic differences and cryptic groupings even at a local level. Lumpfish is semipelagic fish that spawns in shallow coastal areas in the spring. The rest of its life cycle is spent offshore in pelagic feeding areas. However, the presence of immature adults in coastal areas as well as anecdotal spawning events in autumn question the current description of the lifecycle. In project ECOLUMP, we hypothesize that some individuals do not migrate offshore but feed in coastal areas and that these individuals constitute a separate subpopulation or ecotype than the migratory individuals. To uncover this alternate life strategy, we will use an interdisciplinary approach including population genetics, and methods that will allow us to retrace the migratory history of the fish (i.e. microchemistry of calcified structures and stable isotope analyses). A non-lethal biopsy will be developed to determine individual ecotypes. The proportion of resident and migratory lumpfish targeted by both types of fisheries will be quantified during the project. Acoustic telemetry will be used on coastal lumpfish to further document their coastal-offshore movements and behavior after spawning. We will also test whether lumpfish display different innate orientation and migratory tendencies by comparing their swimming behaviors and orientation cues (visual or magnetic) in the sea and in a laboratory.