Add options for plots to be output in lbs

[Schiano-NOAA]

For regions who's stakeholders prefer to see the plots' axis in lbs, it would be good to add an argument to do this so it can scale for lbs.

Need to check if this is only for landings/catch only

[kellijohnson-NOAA]

Some also prefer numbers 🫤 and this also pertains to indices of abundance. @chantelwetzel-noaa has dealt with this a lot 😁 and might be a good resource for what is needed.

[chantelwetzel-noaa]

The default plotting should plot the catch/landings data in the same units input into the model. If a model has a mixture of catch in numbers and weight by fleet, then separate plotting of the data is necessary. In our region, we don't create alternative plots in pounds so adding this functionality would not be necessary for us, but would like to hear input from other regions.

[Schiano-NOAA]

@chantelwetzel-noaa Interesting. Is there an example that uses both numbers and weight by fleet that I can look at?

Also, lbs is a request from the SE which have to present a lot of their catch in lbs as well from requests by stakeholders. I think this is due to a lot of their catch being from recreational fisheries.

[chantelwetzel-noaa]

To clarify, the mixture of catch in numbers and weight could arise in a model from separate fleets (never within a single fleet) which ends up requiring two separate figures (fleets where catch is in weight versus fleets where catch is in numbers) to show all the removals in a model.

I assumed it was likely the SE needing this functionality 😄. We also have catch from recreational fisheries in our assessments, but we use those data in terms of numbers of metric tons in our models, and only plot them in those units as well.