This is the second-to-last entry in a series of articles from the NOAA/NMFS shark tagging expedition that took place in fall, 2009.

Speared Dolphin fish
The dolphin fish, mahi mahi, dorado has a global distribution and is a highly sort after recreational and gamefish species throughout it’s range. In the Southern Californian Bight, they tend to shelter and aggregate under the kelp patties that act as giant natural Fish Attracting Devices (FADS). In other parts of the Pacific Ocean, FADS are placed in the ocean by fisheries in order to aggregate marketable fish species and target them more efficiently.

During one longline shot a dolphin fish was captured as bycatch, and when we lifted it onboard it bore some unusual fresh wounds that may have been the result of an interaction with the broadbill swordfish that we were trying to target as part of our satellite tagging objectives. It was certainly a brutal attack and showed the ability of some pelagic fish species to survive some hideous injuries and near misses.

Oceanic sunfish and the ‘slime factor’
While it is rare to capture an ocean sunfish or Mola mola on the longline, occasionally one becomes entangled in the gear. One day off Catalina Island,
a sunfish briefly joined us onboard for a few minute so we could untangle its large fins from the line. During this process, the researchers noticed that an incredible pervasive slime was found on the the dermal surfaces of the fish. Is this mucous coating some sort of protective coating that reduces predation on these giant creatures? Occasionally sunfish bear the scars of attacks by sharks on their clavus (taillike keel), but this one was completely free of scars, and we were not surprised given its slime factor! Russ Vetter also commented that these huge oceanic beasts can gather considerable speed when required and even leap out of the water. No damage was incurred to the fantastic beast, which was quickly returned to the water unharmed and wearing a brand new satellite tag that will uncover the secrets of its travels.