- Research & Education
- Cape Cod
The big talk this week in the reports of whalewatch trips was the feeding of the various species of toothed and baleen whales. With the Right Whales largely gone, most of this feeding would have been at the expense of small, schooling fish like herring, mackerel, cappelin, and sand launce. The reality of being a sand eel in the northern waters of the Atlantic is fairly simple. You are food. Sand launce, commonly referred to as sand eels, appear to make up the primary diet of not only most of the whale species common in the waters around the Cape, but also most of the seabirds, most of the commercially valuable fish, most of the sharks and most of the seals. In short, if you are bigger than sand launce, you are probably trying to eat sand eels.
Sand launce are fish with two-lobed tails. They are called sand eels due to their body shape. Long and narrow, they are shaped like the number 2 pencil we all used in school. They feed on zooplanton like copepods during the day and commonly dart into the sandy bottom to hide from predators at night, hence their name.
Stellwagen Bank is important to us as naturalists and as whalewatchers for two reasons. The first is the steep sloping walls of the Bank that force the cold, nutrient-rich waters to the surface. The second is that the Bank is capped with a layer of fine sand and gravel, making it an ideal place for sand launce to hide in the sandy surface at night and then move just sixty to eighty feet or so to the surface in the daytime to feed on the huge mats of copepods available to them there.