California Deep-Sea Trawling Expedition
Image slideshow
Deep-sea trawling expedition collecting party (from left to right): John Sparks (American Museum of Natural History), H. J. Walker (Scripps Institution of Oceanography), Leo Smith (Field Museum), Meg Daly (Ohio State University), Janet Voight (Field Museum), Chris Jones (Field Museum), Luciana Gusmaõ (Ohio State University), Susan Mochel (Field Museum), and Kevin Swagel (Field Museum).
Media for California Deep-Sea Trawling Expedition
R/V Robert Gordon Sproul - The ship used during the August 2010 zoology deep-sea trawling expedition.
Chris Jones and the marine technician attaching the otter trawl for our first collection on the cruise. The wood otter boards in the image are paired, and they are positioned such that the hydrodynamic forces acting on them as the boat moves forward, pushes them outwards; these forces prevent the mouth of the net from closing. They also act like a plough, mucking up the seafloor. This creates a turbid cloud, which scares fishes and other creatures toward the mouth of the net.
Chris Jones and the marine technician releasing the otter trawl.
Janet Voight, Kevin Swagel, Chris Jones, and Leo Smith sorting the bottom trawl, which contained mostly flatfishes and sea urchins.
Leo Smith holding a Turbot (Pleuronichthys). This one was one of the most common fishes that we collected in the bottom trawls.
A Pacific Midshipman (Porichthys) collected in a bottom trawl off of San Diego. The white dots on its underbelly are bioluminescent light organs. This fish is called a midshipman because these light organs look like the buttons on a midshipman's uniform. Unlike most fishes, the bioluminescent toadfishes get their chemicals necessary for bioluminescence from their diet.
A small benthic octopus found among the sea urchins.
A bottom dwelling brittle star. The brittle stars or ophiruoids are similar to the traditional asteroid starfishes, but instead of using tube feet for locomotion, they use their arms directly.
Janet Voight holding up one of the many species of Sea Cucumbers we brought up from the sea floor.
An eelpout (Lycodes) that had a tissue sample taken and preserved in liquid nitrogen for future DNA analysis. The orange tag has a unique identifier on it, so we can track the specimen as a voucher for the tissue sample.
A deep-sea bottom crab that is holding eggs on its underside.
A king crab that was brought up from a depth greater than 1,500 feet in a bottom trawl off San Diego.
Kevin Swagel and the marine technician deploying the Issacs-Kidd midwater Trawl off the stern of the R/V Robert Gordon Sproul.
Kevin Swagel and marine technician releasing the net of the Issacs-Kidd Midwater Trawl as the cod end (white PVC tube at end) submerges at the trawl begins to descend to greater than 3,500 feet.
Issacs-Kidd midwater trawl ascending from a depth of greater than 3,800 feet. As the boat is moving, you put out 2.5 times as much wire as the depth you are trying to sample. For this trawl, nearly 9,000 feet of cable was released and then pulled back in over a period of nearly three hours.
A beautiful red jellyfish collected over the San Diego Trench. Like other jellyfishes, this species has venomous nematocysts (stinging cells).
A Highseas Lampfish (Triphoturus) collected in a midwater trawl. The white speckles on its body are bioluminescent light organs.
A very small Dover Sole (Microstomus) collected in a midwater trawl. The eyes of flatfishes, such as this sole, start out like a regular fish with one on each side, but as they mature the eye migrates from the blind side to the eyed side. This individual has recently finished the eye migration.
A Blackdragon (Idiacanthus) with its mouth wide open. The lure in front of its mouth is bioluminescent, and this species uses it to aid predation.
A large and small squid taken in one of the midwater trawls.
One of the classic deep-sea fishes, the Fangtooth (Anoplogaster cornuta). Despite numerous trawls, we only collected a single specimen of the Fangtooth.
A large example of one of the pelagic octopi species that we caught in one of our midwater trawls.
Phronima, a common hyperiid amphipod. These remarkable deep-sea crustacean travels in a house that is a hollowed-out salp test.
Three Big Scale (Melamphaeidae) individuals collected in a midwater trawl. The scales are incredibly delicate in these deep-sea fishes, so these came up in remarkable shape. Frequently, they come up with few to no scales.
A female deep-sea anglerfish with its characteristic, bioluminescent dorsal-fin lure. All of the large individuals of this group of fishes are female, as the males are typically parasitic, even frequently fusing permanently with the females.
A Vampire Squid (Vampyroteuthis) after losing much of its characteristic black skin. We caught several individuals of this rare and beautiful squid.
A deepsea Boafish (Stomias) that has its characteristic unusual scales and ventral bioluminescent photophores. All of the midline fins and the non-terminal end of the barbel in this species are bright red when they come up in the trawl.
A deep-sea Pacific Hatchet Fish (Argyropelecus) in Susan Mochel's hand. This group has the characteristic ventral light organs that match the downwelling light from the surface to avoid casting a shadow beneath them.
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