Gulf of Maine Area Program

Bathymetry

Introduction

Thousands of years ago glaciers, some over a mile thick, sculpted the Gulf of Maine. These glaciers carved deep basins and channels and created banks as they scoured the area and retreated. Rivers and dramatic changes in sea level further shaped the Gulf. (See the Geology section for more information).

Some of the deep basins have begun filling with muds and other sediment, but much of the bedrock and boulders scoured by the glaciers remain exposed today, giving the Gulf of Maine its rocky reputation. Although these rocks and ledges have worried sailors and fishermen for generations, they play an influential role in maintaining the Gulf’s biodiversity.

The many bottom features affect the Gulf’s currents which in turn influence the distribution and abundance of plankton. Also, the many rocks and crevices provide refuges and habitats for the Gulf’s plants and animals. It has long been shown by ecologists that areas of higher rugosity, a measure of surface roughness, have higher abundances and greater diversity of animals such as fish and crustaceans. So, we can thank the glaciers for creating such a heterogeneous environment, an ideal home for the Gulf’s diverse and abundant life.

Statistics and Hypsometry

The mean depth of the study area, defined by the fourteen physiographic regions (physioregions) (Fig. 1), is 245. The deepest spot in the study area is ~3,000 m, found on the seaward edge of Bear Seamount (Fig. 1), but only a small proportion (10%) of the study area is deeper than 300 m (Fig. 2). Approximately 50% of the study area is less than 130 m, and 25% is less than 70 m.

The deepest spot in the Gulf of Maine proper (Fig. 3) is 366 meters, found in the middle of Georges Basin, but only 1.5% of the Gulf is deeper than 300 m. The Gulf of Maine has a mean depth of 139 m with a standard deviation of 75 m. Approximately 50% of the Gulf of Maine is shallower than 150 m, and 25% is shallower than 70 m (Fig. 4).

Figure 1 - Whole Study Area

Figure 2 - Whole Study Area

Figure 3 - Gulf of Maine

Figure 4 - Gulf of Maine

More detailed hypsometric characterization of the Gulf of Maine with data on the areas, depths and volumes of the various physiographic sub-regions.

Bathymetric data layers can be found in the data and mapping section of our site.

Bathymetry Maps