Seabirds as Indicators of Change in Availability
and Commercial Weir Landings of Herring

Krista D.D. Amey
M.Sc., 1998

ABSTRACT

Food availability is the ease with which birds can locate and capture prey. Studies of surface- and sub-surface foragers that feed on the same prey provide information on the vertical distributions of prey and, in turn, availability. The objective of my thesis was to explore the usefulness of seabirds (Arctic Terns, Sterna paradisaea, Common Terns, S. hirundo, Atlantic Puffins, Fratercula arctica, and Razorbills, Alca torda) of Machias Seal Island, N.B., as indicators of change in availability of Clupea harengus (Atlantic herring).
I found that poor weather inhibited the feeding and breeding performance of surface-feeders (S. paradiaea, S. hirundo) but not pursuit-divers (F. arctica, and A. torda). I also found that the surface-feeders had a diet that was more diverse and consisted of a lower proportion of herring than that of the pursuit-divers, attributable to the restrictive two-dimensional foraging range of the surface-feeders. Therefore, I can infer the occurance of yearly changes in the vertical distribution, and hence, availability of herring. I have also shown that the diet of S. paradisaea can predict the total CPUE of the commercial weir fishery two years in advance.

FUNDING ACKNOWLEDGMENTS

EMAN, Environmental Monitoring and Assessment Network

KRISTA'S CURRENT ACTIVITIES...

I spent from mid-April to mid-June 2001 and then again from early-Aug to early-Sep 2001 (Vince came with me for second stint) at Triangle Island Seabird Monitoring Station. For a second season, I was involved in a telemetry study to determine foraging distribution of Cassin's Auklet breeding at Triangle Island - as well as monitoring breeding success, chick growth, diet composition, feeding frequency, adult survivorship and site fidelity for Cassin's Auklet and Rhinoceros Auklet; breeding success, chick growth, diet composition, feeding frequency for Tufted Puffin; breeding success, diet
composition, feeding frequency for Common Murre; and breeding success of Pelagic Cormorant.

Since then I have been working on contract for Michael Dunn at the CWS at Delta. I am analyzing ship survey data, collected primarily by Ken Morgan (CWS), to examine seabird distribution at-sea, the objective of which is two-fold. First, I am examining the portion of sea around Triangle Island and the other four islands, which compose the Scott Islands, to facilitate in the designation of a Marine Protected Area. Second, I will be examining similar data for the entire coast of BC to update the Atlas of Pelagic Birds of Western Canada.

My husband, Vince, the cats and I are doing well and are settling in nicely to British Columbia living. After taking a year off in order to gain some practical experience, Vince has returned to his Master of Architecture program and is doing very well. He is also working part-time for Montgomery Wood Architect Inc.