The 2007 whale watch field season is now behind us. There were many similarities with the 2006 season. It was another year of relatively high numbers of fish-eating whale species: fin whales, humpback whales and at times minke whales. I had few sightings of white-sided dolphins during my field time this year.

Relative abundance of prey species is easily associated with much of what we see during the whale watch season. This is not only true regarding fin and other species of whales but also regarding larger fish and even pelagic birds. To better understand local fin whales it is necessary to look at them in the broader context of the ecosystem in which they live. It is an ecosystem where the marine geography and ocean currents allow for nutrient cycling to ultimately support all of the local marine life including fin whales.

This year we had few sightings of basking sharks and ocean sunfish (known as mola mola). The former feed primarily on calanoid copepods and the latter feed on ctenophores (known as comb jellies). Later in the summer we regularly saw small bluefin tuna that feed primarily on small schooling fish including sand lance. Occasionally they feed on krill that are small shrimp-like invertebrates.

Bird-life was plentiful this year. Wilson’s storm petrels were often observed feeding on copepods and perhaps on krill though they were rarely seen in the large numbers that are sometimes possible for much of the summer. In contrast, greater, sooty and manx shearwaters were seen in larger numbers though the manx were seen to a lesser degree. Relatively large numbers of northern fulmars were forced shoreward by this autumn’s steady easterly winds. These shearwater and fulmar sightings were primarily to the north and east of Race Point. This area was ultimately the area of greatest fin whale concentration. Inshore, between Race Point and Wood End, high summer and autumn concentrations of terns were joined in the autumn by migrating jaegers and gannets. This Wood End to Race Point corridor is regularly used by fin whales during springtime.

All of these animals are a significant part of the world, the ecosystem, the context in which we view fin whales. A primary prey source for many of these fish-eating predators is the sand lance. Sand lance are a small schooling fish found primarily over sandy bottoms along the northeastern USA. Their range includes the western Gulf of Maine where we spend our time. Sand lance feed primarily on copepods. We generally see sand lance four to eight inches in length and approximately a half inch in diameter. But what sand lance lack in size they make up for in number. They are found in dense schools five to ten feet across and a foot or two deep. Other schools are a couple hundred feet in diameter and thirty feet thick. Schools can easily contain from over one hundred to thousands and even tens of thousands of fish. We rarely whale watch in more than 300 feet of water, so in our study area sand lance are found anywhere from the water’s surface to the bottom where they will burrow into the sand.

I often remind passengers that fin whale distribution, and for that matter predatory fish and seabird distribution, tells us as much about prey distribution as it does about predators. Sooner or later almost any discussion of local fin whales is related to their feeding opportunities. Much of their local distribution is predicated by where there is enough food at any given time to make it worth the fin whales’ effort. This is not surprising when one considers that full grown and actively feeding fin whales are believed to consume some 2000 to 2200 pounds of food per day. This puts fin whales at the top of the list of marine consumers (consuming more prey than any other consumer) off the eastern USA. When I was able to identify the prey being consumed by fin whales at the water’s surface this year that prey was sand lance.

With the help of Dolphin Fleet captains and field guides we were able to collect some 815 data lines on fin whales this year. Four hundred and forty-four usable fin whale photo ID shots came from the 197 data lines that had accompanying photographs. Between 15 April and 31 May almost all fin whale sightings were from the northeastern portion of Cape Cod Bay through the Race Point area and on toward the southwest quarter of Stillwater Bank. By the end of May sightings had shifted from the Bay toward the southeastern bank and farther east. From 1 June to 30 September, 155 of the 197 photo ID lines came from the Race Point Channel. There were some data lines from October though none of those lines had photo data.

The Race Point Channel stretches west to east. It is bounded to the north by southern Stellwagen Bank and to the south by the Provincetown Peninsula. The channel is bounded on the east by a deeper set of parallel ridges and valleys. The steepness of bottom slopes combined with tidal currents in Race Point Channel cause dramatic water mixing that is often visible at the water’s surface as upwelling. These currents push nutrients toward the surface and those nutrients feed the microscopic phytoplankton and zooplankton (including copepods) that in turn feed schools of sand lance. At 2000 pounds of food per day a group of ten or fifteen fin whales may potentially take over ten tons of sand lance from this area each day. Bluefin tuna and clusters of minke whales, sometimes 20 or more, joined these fin whales from mid to late summer

This 2007 sighting distribution was similar to our 2006 sightings though there were a couple of Cape Cod Bay records of fin whales between mid July and mid August of 2006. The southern Stellwagen Bank and Race Point Channel area is indeed the area most heavily used by fin whales within our whale watching range. Fin whale concentrations generally shift toward the northern part of the bank during the winter season when we are not out whale watching.

We were fortunate this year with the fin whale distribution relative to the humpback whale distribution. For much of the summer major fin whale distribution was close to or directly along the route to humpback whales that were farther offshore. If this had not been the case we would likely have spent less time watching both species as there would have been greater distances to travel.

With the photo analysis done we have records of 55 individual fin whales for 2007. This includes five mother and calf pairs. Twenty-five of those individuals have previous sighting records. While we also have data and photos for unnamed individuals the following named individuals with known sighting history were photographed this summer:

Matching of calves to mothers has been challenging this year for several reasons. There are the general difficulties involved in photo–identifying fin whales. This combined with the rarity with which we observe mother calf pairs gives us a limited number of photos to work with for matching females with calves. We have, for example, only one record of Goatdance with her calf this entire year. Mother calf pairs are often presumed to spend more time farther offshore, in the area of the Great South Channel, during the summer months. Research access to this area is limited. Also, calves are noticeably larger by the end of the summer and they travel farther from their mothers. Fin whale calves are often weaned by seven to eight months. Consequently, if a late-summer sighted calf is not near to an adult (its mother) it may be not recognized as a calf. We are fortunate in having a couple sightings of Scorpion and her calf for the season. A female named Sunspot was seen with her calf regularly throughout the season. Sunspot and her calf were seen primarily in the Race Point Channel.

Application of this data and photo analysis is broad. We learn more about how fin whales use local waters by observing their geographic distribution. Our data base catalog is being used to develop a catalog for field guides working onboard whale watch boats to help those guides recognize individual fin whales in the wild. This helps whale watch passengers learn more about the lives’ of the individuals seen during whale watch trips. Any field researcher knows that this is a difficult and time consuming task. Our data is also used as researchers from different regions compile data to monitor fin whale populations through out the western North Atlantic. Ultimately this helps to protect fin whales by offering more accurate information to manage human activity in regions where fin whales congregate.

Most photos of fin whales become photographic data for individual identification in the process we refer to as science, but, there are occasional photos that are great in their own right. My favorite photo of the year was taken by Carole Carlson. She captured what I feel to be the most true to life photos of a pair of lunge feeding fin whales. Anyone who has watched lunging fin whales knows that you generally see only a whoosh of white water that is lightning fast. By the time you see the white water the whale has already disappeared beneath the water’s surface.

On a calm evening early this summer Carole photographed two lunge feeding fin whales. They rose on their sides through the water’s surface. Hundreds of sand lance whipped into an escape route through the air by being slightly off-center of the whales’ targeted prey patch. Less than a second later the two whales and the hundreds of airborne fish (not to mention the hundreds of ingested fish) were gone. All that remained was a flat patch of greenish-white water and a boat of awestruck whale watchers. This time though there also remained two beautiful photographs of what we who spend our lives with fin whales very rarely see: the whale actively wrapping its mouth around its prey

!

In closing I would like to acknowledge the help of many people throughout this year’s field season. The Dolphin Fleet field guides and interns. This year’s interns came through the support of Cetacean Society International. The photographs and data from these people were well recorded. Several guides and interns were particularly good at shooting right side chevron, back and dorsal fin sequences. Also, thank you to the Dolphin Fleet captains. Having fin whales close to home is helpful but without the captains’ patience and skill this data and the understanding we gain is not possible. Many captains spent more time with fin whales this year and made sure that guides were able to get good photos before moving to the next animal. Thank you also to Carole Carlson; our research and education director. She coordinated the guides, volunteers and interns, and along with their help, moved that hand written, GPS and photographic data through the computer and to the printing process. All of this was accomplished through the generosity and encouragement of Steve Milliken and the Dolphin Fleet. And certainly thank you to the thousands of you who were supportive and encouraging to our research by joining us as passengers on our whale watching trips. Thank you to you all!!!