Abstract Title

Session S-10E: Evaluation, Conservation and Restoration of Species Associated with High-Relief, Rocky Habitat in the Salish Sea

Keywords

Species and Food Webs

Start Date

2-5-2014 1:30 PM

End Date

2-5-2014 3:00 PM

Description

Octopuses are generalist predators that feed by biting or tearing into prey, or by boring a small hole through the prey’s exoskeleton and injecting a cocktail of paralytic and digestive enzymes. These modes of feeding lead to leakage of prey tissues into the surrounding waters. Scavengers may be attracted to these clouds of prey tissue, or the remnant shells left by the octopuses in midden piles. Because octopuses tend to bring prey back to permanent den sites to feed, these dens could become relatively constant attraction points for scavengers. In the San Juan Archipelago, shrimp, especially Pandalus danae, are likely scavengers, and are also the preferred prey of copper rockfish (Sebastes caurinus). We used time-lapse photography to monitor occupied and unoccupied giant Pacific octopus (Enteroctopus dofleini) dens for evidence of rockfish responding to the presence of octopuses. Occupied dens had significantly higher copper rockfish abundance than unoccupied dens. Occupied dens appeared to host resident rockfish, as the same individuals were routinely observed resting in or near occupied dens. While rockfish and other demersal predatory fishes were occasionally observed at unoccupied dens, fish here were more transient, with the exception of small schools of Puget Sound rockfish (S. emphaeus) and one lingcod. If octopuses facilitate rockfish by attracting prey species, ecosystem-based management of rockfish in the Salish Sea could include the protection of octopuses, such as with the recently adopted octopus protection areas in Puget Sound.

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May 2nd, 1:30 PM May 2nd, 3:00 PM

Facilitation of rockfish by octopus in the Salish Sea

Room 613-614

Octopuses are generalist predators that feed by biting or tearing into prey, or by boring a small hole through the prey’s exoskeleton and injecting a cocktail of paralytic and digestive enzymes. These modes of feeding lead to leakage of prey tissues into the surrounding waters. Scavengers may be attracted to these clouds of prey tissue, or the remnant shells left by the octopuses in midden piles. Because octopuses tend to bring prey back to permanent den sites to feed, these dens could become relatively constant attraction points for scavengers. In the San Juan Archipelago, shrimp, especially Pandalus danae, are likely scavengers, and are also the preferred prey of copper rockfish (Sebastes caurinus). We used time-lapse photography to monitor occupied and unoccupied giant Pacific octopus (Enteroctopus dofleini) dens for evidence of rockfish responding to the presence of octopuses. Occupied dens had significantly higher copper rockfish abundance than unoccupied dens. Occupied dens appeared to host resident rockfish, as the same individuals were routinely observed resting in or near occupied dens. While rockfish and other demersal predatory fishes were occasionally observed at unoccupied dens, fish here were more transient, with the exception of small schools of Puget Sound rockfish (S. emphaeus) and one lingcod. If octopuses facilitate rockfish by attracting prey species, ecosystem-based management of rockfish in the Salish Sea could include the protection of octopuses, such as with the recently adopted octopus protection areas in Puget Sound.