What key difference exists in the first dorsal fin structure between the white marlin and the blue marlin?

The first dorsal fin on a white marlin is relatively small and low compared to the blue marlin's towering structure.

A significant physical trait differentiating the white marlin from the blue marlin is the structure of the first dorsal fin. The white marlin is characterized by a first dorsal fin that is notably smaller and less imposing, described as relatively low, especially when contrasted with the massive, sail-like structure characteristic of the blue marlin. This morphological difference is speculated to relate to differing hydrodynamic priorities in their respective ecological niches. The white marlin’s more compact profile suggests an evolutionary design favoring quick acceleration and maneuverability, perhaps suited for hunting smaller, faster prey in the upper water column, as opposed to the potentially greater power thrusts associated with the larger fin structure of its cousin.