|Client: Oil Spill Recovery Institute|
|Final Report: Overview|
|Appendix 1-Technical description of the LarvaMap package|
|Appendix 2-Pacific herring larval transport modeling|
|Appendix 3-Dungeness Crab Larval transport modeling|
|Download poster presented at the Alaska Marine Science Symposium, Anchorage Alaska, January 16-20, 2012|
LarvaMap – a Web based larval behavior model for Prince William Sound and high latitude Pacific.
Understanding larval transport and survival is critical to effective fisheries management. Larval transport models aid fisheries, habitat and marine protected area decision makers in understanding how ocean circulation and larval behavior affect survival.
The aim of the LarvaMap project was to develop a viable web-based larval transport modeling package, and to test the program by running model simulations of larval transport for Pacific herring and Dungeness crab in Prince William Sound (PWS). LarvaMap is a 3D web-based larval fish and invertebrate transport model connected to ROMS circulation fields for the northeast Pacific. Behavior and development of simulated larvae can be designed and modified based on data for existing species using a “larva library”. The program includes the ability to specify growth and development rates that vary dependent on water temperature, swimming abilities that vary depending on larval size and stage of larval development, and common larval behaviors such as diel vertical migrations. Once behavior for the species of interest has been designed, larval transport models can be specified and run using a straightforward interface. The LarvaMap application is available at the web address: http://services.asascience.com/MapApp/larvamap/.
LarvaMap can use any circulation dataset formatted using the network Common Data Format for Climate and Forecast (NetCDF CF) available through a Thematic Realtime Environmental Distributed Data Services (THREDDS) data server (TDS). Both NetCDF and TDS are oceanographic community standards. LarvaMap output can be viewed in combination with field data and circulation model results using HabitatSpace, a 4D dataanalysis tool previously developed by members of this team for the NOAA Alaska Fisheries Science Center. Our ultimate goal is to develop a web-based larval transport tool that can be used for fisheries managers, researchers and educators. With remote access to circulation fields, the model will be easily relocatable to new areas and species.
Larval models were developed and run for both Pacific herring and Dungeness crab in the PWS area. A detailed literature review of larval development and behavior was carried out for each species, and this was used to design the simulated larvae used in the models. Larval transport models were run for Pacific herring in PWS for the years 2009-2012. Larvae originated at points based on data from aerial surveys of herring spawning carried out annually by Alaska Department of Fish and Game. Simulations ran for the entire larval phase, which is approximately 68 days in PWS. The results of the Pacific herring models showed that there was a substantial and unexpected amount of variation in the predicted final settlement locations for the larvae between years. Results for 2009 showed that a large proportion of the larvae settled in the eastern part of the sound, whereas in 2010 and 2012 the majority settled in the west. 2011 was also different in that many of the larvae were advected out of the sound, where they would presumably not survive. These results are an interesting first attempt to model herring larval transport in PWS, and could be compared with known distributions of juvenile herring in overwintering areas to verify the models.
Models were also run for Dungeness crabs in the PWS area for 2011 and 2012. The results also showed great interannual variation, of a similar magnitude to that seen for herring. The 2011 run showed that the majority of the larvae were retained near to their start point in the southeastern part of PWS, although in 2012 the majority were advected to the western part of the Sound. These results do not appear to implicate larval transport issues as a reason for the decline of Dungeness crab in PWS.