Dissertation
Exploring the life histories of cephalopods using stable isotope analysis of an archival tissue
Doctor of Philosophy (PhD), Washington State University
01/2013
Handle:
https://hdl.handle.net/2376/4774
Abstract
Relatively little is known about the life histories of cephalopods compared to many other groups of major marine predators such as fish, marine mammals, and sea birds. Increased importance of cephalopods to global fisheries in the past forty years and a recognition of the important ecological roles of cephalopods has driven increased research interest into the lives of these enigmatic animals. Still, there is a paucity of information about the life histories of all cephalopods except a few well-studied species.
Stable isotope analysis has become a powerful tool to infer nutritional sources and movement patterns in aquatic organisms. The use of this tool can be extended temporally when used in tissues that have no elemental turnover after formation, or archival tissues, which provide a frozen record of stable isotope composition at formation. In this dissertation I explore the utility of using stable isotope analysis of an archival tissue, eye lens, in cephalopods to help provide sorely needed information about the life histories of this ubiquitous class of marine mollusks.
Here the use of stable isotope analysis of eye lenses is used to investigate possible natal origins of Dosidicus gigas from the northeastern Pacific ocean. This species of large squid has recently undergone a dramatic northward range expansion, pushing the northern extent of occurrence from 32ºN before 1997 to 55ºN by 2008. Data presented suggests squid collected in this study from the coastal US were hatched north of 37ºN. Additionally, eye lens isotope data is used to confirm dietary data from midden analysis of two north Pacific octopuses, Enteroctopus dofleini and Octopus rubescens. This data helps identify these octopus species as potentially providing the predation pressure to maintain a mutualism between a sponge and a scallop. Finally, stable isotope analysis of the eye lens of a hydrothermal vent-associated octopus, Graneledone cf. boreopacifica, demonstrates that this octopus likely did not consume any hydrothermal vent fauna over the course of its lifetime, despite being collected near productive vent habitats. Together these chapters show the utility of this method to help elucidate life histories of cephalopods.
Metrics
96 File views/ downloads
48 Record Views
Details
- Title
- Exploring the life histories of cephalopods using stable isotope analysis of an archival tissue
- Creators
- Kirt L. Onthank
- Contributors
- Raymond W Lee (Advisor)Asaph B Cousins (Committee Member)David F Moffett (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Sciences, School of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 125
- Identifiers
- 99900581650101842
- Language
- English
- Resource Type
- Dissertation