The natural history of Bathypolypus arcticus (Prosch), a deep-sea octopus.
Date
2000
Authors
Wood, James B.
Journal Title
Journal ISSN
Volume Title
Publisher
Dalhousie University
Abstract
Description
There is a major deficit in knowledge about deep-sea and cold-water cephalopod life processes and cycles. Because the morphology of deep-sea cephalopods differs from that of shallow-water cephalopods, it is likely that there are life history, behavioral and physiological differences as well. The main purpose of this work was to study the behavior, physiology and natural history of a deep-sea octopus to provide a comparison for the life processes of the better studied short-lived shallow-water species.
This thesis describes the collection, low-temperature husbandry protocols, copulation, fecundity, brooding, development, and hatching of Bathypolypus arcticus, a deep-sea octopus. The natural diet of B. arcticus includes brittle stars, a prey not normally consumed by shallow-water cephalopods. Hatchling B. arctieus, like hatchlings of near-shore species, grow best when fed live crustaceans and do not thrive when fed frozen foods. Hatchlings do not thrive on a diet exclusively of brittle stars, likely because brittle stars are only ingested when preferred prey cannot be found. The growth rates of B. arcticus are very low (0.117%/d at 2.4°C to 0.779%/d at 9.9°C) compared to those of other octopuses. While age at maturity of all cephalopods is affected by temperature, low temperature by itself does not explain the slow growth rates found. The age at maturity of B. arcticus living at 4°C is conservatively estimated to be at least six years. They lay very large eggs for their size and have a correspondingly low fecundity. They are semelparous and take over 400 days to brood their eggs at 7.5°C. Low-quality diets, low activity levels, low growth rates, low fecundity, large eggs and long life spans indicate that B. arcticus does not follow the typical "live fast and die young" cephalopod paradigm.
Thesis (Ph.D.)--Dalhousie University (Canada), 2000.
This thesis describes the collection, low-temperature husbandry protocols, copulation, fecundity, brooding, development, and hatching of Bathypolypus arcticus, a deep-sea octopus. The natural diet of B. arcticus includes brittle stars, a prey not normally consumed by shallow-water cephalopods. Hatchling B. arctieus, like hatchlings of near-shore species, grow best when fed live crustaceans and do not thrive when fed frozen foods. Hatchlings do not thrive on a diet exclusively of brittle stars, likely because brittle stars are only ingested when preferred prey cannot be found. The growth rates of B. arcticus are very low (0.117%/d at 2.4°C to 0.779%/d at 9.9°C) compared to those of other octopuses. While age at maturity of all cephalopods is affected by temperature, low temperature by itself does not explain the slow growth rates found. The age at maturity of B. arcticus living at 4°C is conservatively estimated to be at least six years. They lay very large eggs for their size and have a correspondingly low fecundity. They are semelparous and take over 400 days to brood their eggs at 7.5°C. Low-quality diets, low activity levels, low growth rates, low fecundity, large eggs and long life spans indicate that B. arcticus does not follow the typical "live fast and die young" cephalopod paradigm.
Thesis (Ph.D.)--Dalhousie University (Canada), 2000.
Keywords
Biology, Ecology., Biology, Zoology.