Modern Science Proves Historical Maps Accurately Identify Fish Habitat

NOAA Fisheries –

NOAA Fisheries scientists used modern acoustic technology to successfully verify the accuracy of old (1924-2003) maps of the Alaska sea floor and validate their use in managing sustainable fisheries. 

Data from spring and summer 2013 single beam acoustics surveys–using a Simrad EK60 echosounder–confirmed historic depth soundings made by hand-lowering a weighted rope from a small boat navigated by visual triangulation in uncharted waters.

The old depth soundings were recorded on charts known as smooth sheets. Detailed, digitized 3D maps created from the old smooth sheets help describe and identify important nearshore habitat for commercially and ecologically important fish species.

The study was part of the Gulf of Alaska Integrated Ecosystem Research Project (GOA IERP), jointly funded by NOAA and the North Pacific Research Board, which seeks to understand what affects juvenile survival of five fish species in the Gulf of Alaska. This information is critical for sustainably managing fisheries.

The five target species of the GOA IERP — pollock, cod, arrowtooth flounder, sablefish, and Pacific ocean perch — live offshore as adults but depend on shallow, protected inshore areas that serve as nurseries for juveniles. Zimmermann’s smooth-sheet bathymetry was ultimately applied to a GOA IERP study to model and map habitat for these juvenile nurseries that will be extended to develop a juvenile habitat modeling program for future Essential Fish Habitat (EFH) updates.

Read more