Multiple-batch spawning: a risk spreading strategy disarmed by highly intensive size-selective fishing

Here we upload the files that support our research on the role of
risk-spreading strategies in the light of fisheries-induced evolution. The
code is stored in Zenodo. Abstract from the paper: Can the advantage of
risk-managing life-history strategies become a disadvantage under
human-induced evolution? Organisms have adapted to the variability and the
uncertainty of environmental conditions with a vast diversity of
life-history strategies. One of such evolved strategies is multiple-batch
spawning, a spawning strategy common to long-lived fishes that ‘hedge
their bets’, by distributing the risk to their offspring on a temporal and
spatial scale. The fitness benefits of this spawning strategy increase
with female body size, the very trait that size-selective fishing targets.
By applying an empirically and theoretically motivated eco-evolutionary
mechanistic model that was parameterized for Atlantic cod (Gadus morhua),
we explored how fishing intensity may alter the life-history traits and
fitness of fishes that are multiple-batch spawners. Our main findings are
twofold; first, the risk-spreading strategy of multiple-batch spawning is
not effective against fisheries selection, because the fisheries selection
favours smaller fish with lower risk-spreading effect,
and second, the ecological recovery in population size does not
secure evolutionary recovery in the population size structure. The
beneficial risk-spreading mechanism of the batch spawning strategy
highlights the importance of recovery in the size structure of overfished
stocks, from which a full recovery in the population size can follow.