In the 19th century, Americans were careful to avoid wasting food. Scraps of chicken, ham, or fish from supper would be mixed with mayonnaise and the leftover “relishes” from dinner (usually celery, pickles, and/or olives) and served on top of lettuce for the next day’s lunch. The fish used in these lunch salads was usually salmon, white fish, or trout — most Americans weren’t even aware of tuna. Toward the end of the 19th century, middle-class women began going out in public more often to department stores, lectures, and museums. Social conventions kept these women from eating dining in saloons for men, so lunch restaurants catering to women began to open. They served the same meals that women served one another in the home: salads. Fish and shellfish salads were popular offerings. When further social and economic changes saw women entering the workforce as office and department store workers, restaurants realized that these working women needed something familiar but quick to eat, since their lunches were now time-limited. Lunch counters patronized by these working women began serving fish salads in between two pieces of bread. This sped up table turnover and also encouraged women to get their lunches to go. Canned tuna was introduced in the early 20th century. It was embraced by lunch counters and home cooks alike, as it helped them skip a step when making tuna salads or tuna fish sandwiches. Over time, the canned tuna fish sandwich became a true American classic that is still enjoyed today. However, there was a downside to its meteoric rise — the sandwich’s immense popularity also led to the development of a global tuna industry responsible for depleting the levels of tuna in the ocean and causing harm to dolphins through fishing practices.