Forecasting Pacific saury (Cololabis saira) fishing grounds off Japan using a migration model driven by an ocean circulation model

Reduced body weight of Pacific saury (Cololabis saira) causes delayed initiation of spawning migration

“…There were large annual variations in obtained optimal swimming speed during spawning migration (Figure 5c). As discussed in Kakehi et al (2020), swimming speed used KMM2020, and our migration model is migration speed, that is, long‐term net travel speed towards a fixed direction, not instantaneous swimming (cruising) speed. Therefore, a case in which fish randomly swim with 4.0 × BL s −1 , migration speed over a day becomes almost 0 m day −1 .…”

“…There they feed on the abundant copepods which occur in those regions (Miyamoto et al, 2020; Odate, 1994). Subsequently, they commence spawning migration towards the west in August or September (Kakehi et al, 2020; Miyamoto et al, 2019).…”

“…In relation to the migration characteristics of the Pacific saury, Kakehi et al (2020) developed a migration model (hereafter referred to as KMM2020) to forecast migration routes of age-1 Pacific saury from pre-fishing distribution in June to July to early fishing grounds in August to September using parameters related to northern and spawning migration. In the model, the Pacific saury was assumed to migrate north, staying within a certain temperature zone with a seasonal northward shift of isotherm lines until July 31.…”

Achieving sustainable and climate‐resilient fisheries requires marine ecosystem forecasts to include fish condition

“…Importantly, the physical‐biological crossflow is allowing for the identification of “ecologically meaningful” physical data fields (Hobday & Hartog, 2014). This is progressing species distribution models that are currently based on sea‐surface temperature to include more informative four‐dimensional and derived metrics of ocean state such as subsurface and depth‐integrated metrics, which has improved the predictive capabilities of ecological models of fish distributions used in nowcasting and forecasting applications (Brodie et al., 2018; Kakehi et al., 2020; Scales et al., 2017). For example, forecasting the early fishing grounds of Pacific saury ( Cololabis saira , Scomberesocidae) using a migration model forced by an ocean circulation model may increase fishing revenue, because catches from earlier in the season trade at higher prices (Kakehi et al., 2020).…”

“…This is progressing species distribution models that are currently based on sea‐surface temperature to include more informative four‐dimensional and derived metrics of ocean state such as subsurface and depth‐integrated metrics, which has improved the predictive capabilities of ecological models of fish distributions used in nowcasting and forecasting applications (Brodie et al., 2018; Kakehi et al., 2020; Scales et al., 2017). For example, forecasting the early fishing grounds of Pacific saury ( Cololabis saira , Scomberesocidae) using a migration model forced by an ocean circulation model may increase fishing revenue, because catches from earlier in the season trade at higher prices (Kakehi et al., 2020). The identification and processing of useful physical fields and metrics at spatial and temporal resolutions of relevance to the systems and species of interest is critical for enhancing both skill in marine ecosystem forecasts and their overall utility.…”