Using the past (& present) to predict the effects of changing food environment and temperature on Northeast Arctic cod in the Barents Sea.

Popular science presentation - in Norwegian:

Tåler torsk varmere forhold og hvordan vil dette endre det de spiser?

Torsk er en nøkkelart i Barentshavet; torsken er uten tvil en av de mest økologisk og økonomisk viktige artene i Nord-Atlanteren. Til tross for at den nordøstarktiske torskebestanden er i god stand og høstes bærekraftig er den truet av virkningene av globale klimaendringer.

Økt temperatur blir ofte sett på som den eneste effekten av klimaendringer på marint liv, men konsekvensene er imidlertid mer vidtrekkende enn som så; torsken kan påvirkes på mange og til dels ukjente måter.

En understudert effekt av klimaendringer er forandringer i mattilgjengeligheten for torsken. Antall og utbredelse av torskens vanlige byttedyr, som lodde og sild, kan endre seg og slik påvirke hva som er tilgjengelig som mat for torsken. Videre kan Barentshavet bli hjemsted for et økt antall invaderende arter, som snøkrabbe og rød kongekrabbe, noe som kan endre miljøet og økosystemet og dermed forstyrre forholdet mellom torsk og deres normalt foretrukne mat.

Et avgjørende spørsmål er derfor hvordan endringer i temperatur og mattilgjengelighet påvirker torsken både på individ- og bestandsnivå.

I dette unge forskningstalentprosjektet har vi en unik mulighet til å bruke omfattende datasett som spenner over mange år sammen med innovative modelleringsverktøy for å undersøke virkningene av økt temperatur og endret mattilgjengelighet på nordøstarktisk torsk.

Popular science presentation - in English:

Can cod take the heat, and how will it change what they eat?

Cod is a key species in the Barents Sea; it is arguably one of the most ecologically and economically important species in the North Atlantic. Despite the Northeast Arctic cod stock being in good condition as well as harvested sustainably, it is under threat from the effects of global climate change.

Climate change is often thought of and studied as the single effect of increased temperature. However, the effects of climate change are more wide-reaching than that and can affect the cod in unknown ways.

An understudied combined effect of climate change is changing food availability for the cod. The cod’s normal food, like capelin and herring may change in abundance and distribution affecting the cod’s diet. Furthermore, the Barents Sea may become home to an increased number of invasive species, like the snow crab and red king crab, potentially disrupting the environment and relationships between cod and their normal food.

A crucial question therefore is, how do changes in temperature and food availability affect cod at both the individual and population level?

In this young research talent project, we have the unique opportunity to use rare and extensive long-term datasets, combined with innovative modelling tools to investigate the impacts of increased temperature and changing food availability on Northeast Arctic cod.

Many studies focus on a single driver within global climate change, primarily temperature, but fail to consider the wider implications of environmental change at the individual and population level. In this project, we will develop and apply a multifaceted innovative modelling approach, combined with extensive high-resolution long-term data to evaluate the potential impacts of changing food environment (through prey availability, prey composition, diet: prey type, energy content and digestibility) and temperature on the economically and ecologically important Northeast Arctic cod (Gadus morhua) in the Barents Sea

We will use extensive unique spatio-temporal datasets, including the NEA cod stomach content database, spatiotemporal prey abundance datasets that reflect NEA cod diet, and environmental datasets for temperature in the Barents Sea. These data sources together with existing empirical knowledge will be used to quantitatively analyse past and present changes in predator-prey dynamics, prey availability and NEA cod diet (WP 1 & 2).

This vital information will be used to parametrise, and develop, novel trait-based models to examine the effects of changing temperature and spatio-temporal food environment on important population characteristics, such as survival, growth, reproduction, mortality, and productivity of NEA cod (WP3).

We will use a mechanistic approach, focusing on the well-known respiratory physiology mechanism allowing us to provide predictions of temperature- and food-environment-induced adaptations for life-histories and behaviour at the population level, allowing for an innovative study on the synergistic effects of external stressors on arguably one of the most ecologically and economically important species in the North Atlantic, Northeast Arctic cod.