diff --git a/R/atu-index.R b/R/atu-index.R
index 42b204f..e4f8523 100644
--- a/R/atu-index.R
+++ b/R/atu-index.R
@@ -1,8 +1,7 @@
 .atu_index <- function(
     x,
     date,
-    atus,
-    msgs = TRUE) {
+    atus) {
   
   x <- pmax(x, 0)
   x <- cumsum(x)
diff --git a/R/date-atus.R b/R/date-atus.R
index f7455cd..ee27fb6 100644
--- a/R/date-atus.R
+++ b/R/date-atus.R
@@ -12,8 +12,7 @@
 date_atus <- function(
     x,
     atus = 600,
-    start_date = as.Date("1972-03-01"),
-    msgs = TRUE) {
+    start_date = as.Date("1972-03-01")) {
   
   check_data(x, list(date = dttr2::dtt_date("1970-01-01"), temperature = c(1, NA)))
   chk_date(start_date)
@@ -51,8 +50,7 @@ date_atus <- function(
     dplyr::group_modify(~.atu_index(
       .x$temperature,
       .x$date,
-      atus = atus,
-      msgs = msgs), .keep = TRUE) |>
+      atus = atus), .keep = TRUE) |>
     dplyr::mutate(end_date = dttr2::dtt_dayte(end_date, start_date),
                   start_date = start_dayte) |>
     dplyr::select(c("year", "start_date", "end_date", "atus"))                  
diff --git a/man/date_atus.Rd b/man/date_atus.Rd
index 1ab2c04..c49b51b 100644
--- a/man/date_atus.Rd
+++ b/man/date_atus.Rd
@@ -4,7 +4,7 @@
 \alias{date_atus}
 \title{Calculate Date of Accumulated Thermal Units (ATUs)}
 \usage{
-date_atus(x, atus = 600, start_date = as.Date("1972-03-01"), msgs = TRUE)
+date_atus(x, atus = 600, start_date = as.Date("1972-03-01"))
 }
 \arguments{
 \item{x}{A data frame with two columns \code{date} and \code{temperature}.
@@ -18,8 +18,6 @@ mean daily water temperature in degrees centigrade.}
 within each year to consider (the year is ignored).
 #' If \code{start_date} occurs before the \code{end_date} (when ignoring the year)
 then the window is considered  to span two calendar years.}
-
-\item{msgs}{A flag specifying whether to provide messages.}
 }
 \value{
 A tibble with four columns \code{year}, \code{start_date}, \code{end_date} and \code{atus}.