Spatiotemporal modelling of Greenland halibut maturation across the Northwest Atlantic

Abstract Modelling life history trait variation at appropriate spatial and temporal scales is crucial for understanding population dynamics developing effective fisheries management strategies. However, most efforts to model traits ignore correlations make a priori assumptions about the structuring of populations, potentially clouding ability recognize true structure. Here we develop spatiotemporal maturation models Greenland halibut (Reinhardtius hippoglossoides) in Northwest Atlantic, species with large-scale movement patterns that can lead uncertainty regarding stock boundaries. Our analysis using data from three Fisheries Oceans Canada survey regions, Baffin Bay Davis Strait eastern Canadian Arctic, Newfoundland Labrador (NL), northern Gulf St. Lawrence (GSL), first such large scale. We also extend traditional binary maturity status multinomial one accounts seasonal changes maturation. Results show decreasing trend size across entire area. Spatial results provide new insight linking south (Northwest Atlantic Organization Subdivision 3Ps) GSL rather than NL stock. highlight parts area, where smaller waters both north south. Multinomial identify areas may be important reproductive development summer fall. analyses reveal constraints on correspond well-known positive association between fish length bottom depth. Broad-scale high resolution traits, as those performed here maturation, recurrent environmental or habitat characteristics might not otherwise evident stock- survey-specific basis.