13 Tables
To demonstrate how LTA results can be summarized, tabularized, and plotted, we will use the same built-in dataset as the previous chapter: density/abundance estimates for the Hawaiian EEZ in 2010 and 2017 for striped dolphins, Fraser’s dolphins, and melon-headed whales, ran with only 100 iterations:
We created these LTA results using the following built-in processed dataset:
Summary tables
To summarize lta()
results using the standard table format provided in recent NOAA stock assessment reports, use the function lta_report()
.
Providing the cruz
object is not required, but if it is not provided, one of the five summary tables ($table1a
below) will not be returned.
Table 1 in reports: Sample sizes
Table 1a
If cruz
was provided, $table1a
1a will include total sighting counts for all species in the years from lta_result
, broken down by region. The Ntot
column holds all sightings, regardless of effort status or Beaufort sea state. Nsys
holds counts of systematic-only sightings (i.e., EffType = “S” and Bft <= 6), which may still include sightings that are beyond the species-specific truncation distance and were therefore excluded from density/abundance estimation.
These counts are provided separately from the $table1b
slot below, since those counts are based on the lta_result
object, and will not include sightings for species that did not have a specific LTA estimate specified when it was made. We also include this separately so as to give the user full flexibility in how they summarize sighting counts by region/population/stock.
Table 1b
This table holds sighting counts used in estimates of density/abundance. The rows match the rows for Tables 3 and 4. In this table, columns are still prepared for total sightings (Ntot
) and systematic sightings (Nsys
), but they are left blank, since it is not clear how sightings from multiple regions in $table1a
would be concatenated for this table. The user can fill in those gaps accordingly.
Appendix tables
Table A2: Effort totals (parsed by Beaufort sea state)
tables$tableA2
$`2010`
# A tibble: 1 × 10
Species Stratum Effort B0 B1 B2 B3 B4 B5 B6
<chr> <chr> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
1 all HI_EEZ 15147 0.00127 0.0127 0.0383 0.116 0.478 0.306 0.0481
$`2017`
# A tibble: 1 × 10
Species Stratum Effort B0 B1 B2 B3 B4 B5 B6
<chr> <chr> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
1 all HI_EEZ 14925 0.000845 0.0103 0.0366 0.115 0.311 0.353 0.173