West Coast Expedition
July 20 - August 30, 2002
West Coast of North America
July 22, 2002: Day #3Mendocino Ridge Dive (T448)
Our main objectives on this dive were to determine the distribution of brooding female octopuses, to photo-document brooding female octopuses and eggs, to determine the distribution of sculpin nests and to photo-document these nests and sculpin brooding behavior. We planned to collect specimens and eggs from clutches of each species. We did not observe the large numbers of brooding sculpins that were present in the 2000 and 2001 dives at the same location in late summer. We did, however, observe many brooding females of the octopus species Graneldone boreopacifica. We photo-documented eggs with several brooding females, and we identified one male individual in the area.
We were able to collect a brooding female G. boreopacifica and a sample of the eggs from her clutch (29 eggs). This is the first collection of late stage eggs from G. boreopacifica as well as the first documentation of an entire clutch for this species. We will be able to determine several key components of the reproductive biology of G. boreopacifica from this sample such as the range of development of the embryos in the clutch, whether more than one male contributed to the clutch, and the physiological state of the brooding mother.
We collected some organisms from the seeps in the area, also. These collections include 11 seep clams (Vesicomyidae), 12 seep tubeworms (Lamellibrachia barhami), 2 snails (unidentified) and a brittle star (Ophiuridea). The clams and tubeworms will further our understanding of the dispersal capabilities of these seep organisms. We plan to use these samples to study the population genetics and evolutionary history of the clams and tubeworms as well as that of the endosymbiotic bacteria that they harbor. We also collected four basalt samples.
Though we did not meet all of the objectives for this dive, it was as a very productive dive that will contribute significantly to our understanding of several deep-sea organisms.
C Robert Young