Project Description

The goal of this project (Julie Nielsen’s Ph.D. dissertation) is to develop quantitative methods to describe and quantify large-scale movement patterns of demersal fish species such as Pacific halibut, Pacific cod, and sablefish using data gathered by electronic tags. Detailed information on adult seasonal migrations and juvenile dispersal for these fish species is currently limited but is needed to assist and improve the management of these highly valuable commercial species in Alaska. Large-scale movement of pelagic fish species such as tuna can be determined by light-based geolocation, where archival tags that record light intensity can provide information on the time of local noon (longitude) and sunrise/sunset (latitude). However because light is limited for demersal fish that inhabit deep waters and high latitudes during winter, other methods of geolocation are needed for demersal fish in Alaska. We are assessing the potential usefulness of newly-developed archival tags that measure the earth’s magnetic field to determine whether this technology might provide more information about fish movement in Alaska. We are also implementing a state-space geolocation model that will incorporate multiple types of data (depth, temperature, light, magnetic field intensity, and acceleration) from archival tags as well as information about how fish move on a daily basis from acoustic telemetry. With this model, which will provide an estimated position of the fish (along with estimated uncertainty in the position) for each day the tagged fish is at liberty, researchers will be able to identify spawning grounds and migration pathways, determine the timing and the proportion of fish that participate in spawning migrations each year, and characterize movement of fish from juvenile to adult areas. The model is being implemented based on Pacific halibut data, but we are working with Pacific cod and sablefish researchers to ensure it is useful for characterizing the large-scale movement of other demersal fish species

Project Funding

Rasmuson Fisheries Research Center, Pollock Conservation Cooperative Research Center, North Pacific Research Board, National Undersea Research Program
Start Date: 2010-09-00
End Date: 2016-06-00

 

 

Research Team