EXERCISE 5

Think of a small coding project to try using the examples above as a template.

Ideas:

• Reset seabed ploughing rate of all or selected gears to zero
• Reset pelagic fishing to more or less than the baseline
• Apply a feeding rate penalty to a selected guild - to represent the impact of litter

Hints: the model object contains some ‘multiplier factors’ to make it a bit easier to create scenarios. These are:

• model$data$fleet.model$gear_mult - a vector of 12 values - multipler applied to gear avtivity rates (default = 1)
• model$data$fleet.model$HRscale_vector_multiplier - a vector of 12 values - multipler applied to fishing mortlaity rates for each guild (default = 1; order of elements as in model$data$fleet.model$HRscale_vector
• model$data$biology.scenarios$uptake.multiplier - 16 x 2 dataframe - multiplier applied to the maximum uptake rates of each guild in the inshore and offshore zones (default = 1) - represents a non-lethal effect eg plastic ingestion
• model$data$biology.scenarios$additional.mortality - 16 x 2 dataframe - additional mortality (% per year) applied to each guild in the inshore and offshore zones (default = 0) - represents a lethal effect eg wind turbine collisions