Fish

How are Atlantic mackerel (Scomber scombrus) impacted by food availability and temperature? An Individual-Based Modelling (IBM) approach.

ROB BOYD

Mackerel in the northeast Atlantic (NEA) are of huge commercial importance, with catches expected to surpass 1,000,000 tonnes in 2017. These catch rates are well in excess of those advised by the International Council for the Exploration of the Seas (ICES), rendering the stock at “moderate” risk. This is set to be exacerbated by a northwestward expansion of the stock’s range, into the waters of states not bound by current fishing agreements and with autonomous quotas. It is therefore important to understand what is causing the shift in NEA mackerel distribution, and how it may change in the future.

It has been suggested that the availability of plankton and Sea Surface Temperature (SST) are important drivers and using remotely-sensed data, both can be mapped in space and time. The resultant maps can then be translated to the ontogeny of individual mackerel, using an Individual-Based Model (IBM) with a recently-proposed energy budget. SST- and food-driven migration rules can also be incorporated at the individual level, meaning that both the population dynamics and spatial distribution of NEA mackerel emerge from simulations.

Data from the fishery, scientific surveys and experiments are used to gauge the model’s performance. It is hoped that once calibrated the model will help to elucidate the drivers of NEA mackerel range expansion, and may provide spatially-resolved population metrics with potential to supplement current stock assessment methods.

 Click here to see my poster at the 2016 British Ecological Society conference in Liverpool.