GOAIERP scientists study what environmental conditions and habitats are important in sablefish survival
In 2008, a team of scientists at the Auke Bay Laboratories initiated several dedicated research projects aimed at understanding ecological and management issues concerning Alaska sablefish (Anoplopoma fimbria). One of these projects is led by Dr. Kalei Shotwell and deals specifically with exploring the driving mechanisms surrounding the highly variable and uncertain survival of young sablefish. The project began with two main goals: 1) determine if an index of young sablefish could be created from historical data and 2) investigate whether measures of the environment can be used in a model to predict the survival of these young fish. Toward the first goal, Dr. Shotwell collected the available data from short-term surveys and found that it was not consistent enough in space and time to be used within the current sablefish assessment model. However, the information can be used for helping understand the best habitat for young sablefish to settle upon after their long journey to the nearshore. Dr. Shotwell along with Dr. Jodi Pirtle of the Benthic Habitat Project will be using this information to develop habitat suitability models and maps to characterize the nearshore benthic habitat for sablefish and the other focal species. These maps will be used by several components of the GOA Project, specifically the modeling component to inform their individual based model trajectories.
The search for environmental predictors for the second goal of Dr. Shotwell’s sablefish project has led to investigating ways to include environmental information in stock assessment. The first breakthrough was the discovery of a relationship between the North Pacific Polar Front and sablefish survival (Shotwell et al. 2014). Colder than average wintertime measures of this large-scale ocean feature in the central North Pacific were found to create good survival conditions for young sablefish. This relationship led Dr. Shotwell and her co-authors (Dr. Dana Hanselman and Dr. Igor Belkin) to put forward a conceptual model of sablefish early-life survival which was termed the ODDS model for Ocean Domain Dynamic Synergy. It is basically a description of the pressures that might influence the survival of young sablefish as they journey from where they are born in the deep ocean slope, through their ride on the waves of the ocean gauntlet, and finally as they settle to their habitat homes in the nearshore. Answering the “What are the Odds?” question for sablefish has led Dr. Shotwell to work with several researchers (GOA Project included) to consider the influence of other environmental measures such as mesoscale eddies, upwelling, freshwater output, nearshore production, pink salmon competitors, and seabird predators. The results of these projects are forthcoming and when completed Dr. Shotwell plans to work with the lead authors of these projects to collect the relevant indicators that will serve as time series that support the ODDS model of early-life survival. These indicators will be compiled in an annual graphical report card to be included in the individual stock assessment reports. The sablefish ODDS report card may be used to assist scientists and managers in understanding what may influence sablefish survival and also visually see the changes of these environmental indicators over time.
Shotwell, S.K., D.H. Hanselman, and I.M. Belkin. 2014. Toward biophysical synergy: Investigating advection along the Polar Front to identify factors influencing Alaska sablefish recruitment. Deep-Sea Reaserch II. Special Issue, Fronts, Fish and Top Predators. http://dx.doi.org/10.1016/j.dsr2.2012.08.024.