BATHYM100 contains bathymetry lines for the Gulf of Maine at a scale of 1:100,000 showing depth in 10 meter intervals. This dataset was developed by the Maine Geological Survey using USGS 30 X 60 minute series topographic-bathymetric maps. Bathymetric contours are coded with depth in meters (10 meter interval mean lower low water datum). Spatial topology varies from good to poor.
This data shows generally where tuna are caught, smaller areas of increased importance to the fishery and a handful of areasthat were identified as being ver important to fishery. In the interviews, the tuna fishermen talked about the challenges of drawing lines on the chart because they chase tuna over most of the Gulf of Maine and each year, where they catch tuna may change. The concern about wanting to accurately represent the data about fishing areas while not excluding other areas from fishing highlights the challenge of attempting to map with fishermen who fish for pelagic species such as tuna.
Tuna are caught by rod and reel or harpooned. Tuna are present in the Gulf of Maine in the spring, summer, and fall with most of the tuna fishing occurring in the waters close to the coast of Maine in July, August, and September.
Interviews were conducted with both tuna fishermen and fishermen who are knowledgeable about where tuna fishermen fish through personal relationships or seeing them out on the water.
The data gives a sense of the vast area fished off the coast of Maine as well as the complexity of fisheries and gear types across areas. It shows areas of fishing from only selected harbors or regions, however, and represent an incomplete “snapshot” from an ongoing project. It should not be viewed as representing a complete data set for Maine’s fisheries, but rather as one step towards understanding fisheries-use patterns offshore and methods for documenting them.