By Nadine Pinnell
After many decades during the mid to late 1900s, when it was very rare to see a humpback in B.C.’s coastal waters, these whales are returning to the B.C. coast. Commercial whaling of the 1800 and 1900s had severely reduced populations across the North Pacific. Prior to whaling, it is estimated that there were over 15,000 humpback whales in the North Pacific ocean including a population of as many as 100 humpbacks returning yearly to the Strait of Georgia. It has been reported that these whales would often enter Vancouver Harbour and Burrard Inlet. During the 20th century an estimated 200,000 humpback whales were killed world-wide, reducing the world population by 90%. Due to this large decline, the International Whaling Commission ended whaling for humpbacks in all oceans in 1966. By this time, the North Pacific humpback population was reduced to an estimated 1200 to 1400 individuals. Estimates, based on research conducted in the early 1990s, suggest that the humpback population has rebounded to around 6000 individuals in the North Pacific. The North Pacific humpback population is now listed as threatened by COSEWIC (Committee on the Status of Endangered Wildlife in Canada) and as endangered by the U.S. Endangered Species Act. While it appears that humpback populations are increasing, a possible decline in humpback abundance during the late 1990’s, concern over threats such as ship strikes, entanglement in fishing gear,reductions in food supply and large measures of uncertainty in current population estimates mean more research is needed.
In late November, SPLASH (Structure of Populations, Levels of Abundance and Status of Humpbacks) met at the Vancouver Aquarium Marine Science Centre to continue its work on a project that is examining the complex population structure of humpbacks and is working to establish a more reliable estimate of the population numbers and trends of North Pacific humpback whales. The steering committee is comprised of 15 members from 11 different organisations representing Russia, Japan, Mexico, Canada and the United States. This large, multi-agency and multi-national approach is necessitated by the far-ranging and complex migratory patterns of the North Pacific humpback.
SPLASH started in the winter of 2003/2004 and will take place over three winters (in breeding areas) and two summers (in feeding areas) with analysis running until 2007. The project employs photo-identification and biopsy sampling as the primary field methods to study the humpbacks of the North Pacific. Photo identification involves taking high quality photographs of each individual humpback tail fluke. Each fluke is unique, like a fingerprint, allowing researchers to develop a catalogue of humpbacks for each area. Researchers can then compare catalogues and determine which humpbacks are using which areas. Biopsy sampling (using darts to collect small tissue samples) gives researchers information on both the health and genetics of humpbacks, especially in providing information on which populations are interbreeding.
One of the key successes of SPLASH is that all partner organisations will use consistent methods, this will ensure that studies in one area can be compared with studies in another area. This consistency is especially important for studying humpbacks, which have a much looser migration compared to other species such as gray whales who travel back and forth between the same breeding and feeding areas and at the same time each year. While it appears that individual humpbacks migrate to the same feeding area each year, there is evidence that a small number of individuals will visit different breeding areas. SPLASH aims to provide more information on this phenomenon.
Although the project began just last winter (2003), the structure of the various humpback populations is already being unraveled in BC. John Ford, SPLASH steering committee member and Director of the Cetacean Research Program at Fisheries and Oceans Canada (DFO) describes the BC humpback populations as an “interesting case”. According to him, the SPLASH research conducted by DFO is giving us a much better picture of where the BC humpbacks migrate and has provided new evidence that humpbacks may be using our coast year round, including winter months. Ford says, “A large number of humpbacks are using Dixon Entrance into late October and another group of up to 200 humpbacks congregate off southeast Moresby Island from May to October”. “Some whales are just leaving as others are showing up,” says Ford. Interestingly, a hydrophone that Dr. Ford has installed at Langara Island off the northwest side of the Queen Charlotte Islands recorded humpback whales “singing” in January. This confirms reports from lighthouse keepers and others in the area that humpbacks are found there throughout the year. In fact, Ford has heard multiple humpback songs overlapping in the recordings, suggesting that there are a lot more whales than previously thought. While not directly part of SPLASH, the recordings from the Langara Island hydrophone have implications for understanding humpback populations. During the summer months humpbacks in BC are mostly silent, only vocalizing to coordinate group feeding – generally, grunting sounds. Singing, done mainly by males, is generally thought to be associated with breeding behaviour. Ford says this singing may indicate that breeding is occurring in BC waters or may just be lonely humpback males practicing their calls before they head back to breeding grounds. However, these recordings raise more questions than they answer and Dr. Ford is hoping to undertake a winter cruise in the coming years to gain a better understanding.
As part of SPLASH, DFO has conducted four major survey cruises and several smaller surveys of the BC coast over the past year(2003-2004). The surveys have been very successful, surpassing their goal of collecting 100 ID photos and 50 biopsy samples. In total, DFO has contributed over 500 ID photos and 76 biopsies to SPLASH which has collected over 5000 ID photos and nearly 1500 biopsy samples to date.
Initial results of SPLASH research supports speculation that BC appears to be a transition zone between two feeding areas. Humpback whales that are seen off the south west coast of Vancouver Island are a from a different population than the humpbacks seen off the North Coast or around the Queen Charlotte Islands. Mexican researcher Jorge Urban from Universidad Autónoma de Baja California Sur in La Paz expects that when the data are compiled many of the Baja humpback ID photos will match B.C. ID photos.
While each institution is working to remove duplicate photos, the main push to compile all the data from across the Pacific will begin in 2005 and be completed by 2007. This will involve sorting through the thousands of ID photos from the various areas and looking for matches. Matches will help researchers track movements of individuals between the various breeding and feeding areas.
The improvement in knowledge of humpback life history provided by SPLASH will help conserve their populations. Examination of ID photos will allow researchers to see evidence of scarring from entanglements in fishing gear and collisions with vessels, providing better information on how frequently and where these events occur, improving the opportunity for mitigation and response to incidents. These findings challenge claims by oil and gas proponents who argue that seismic exploration can occur on the BC coast when whales aren’t there. If, as it appears, humpback whales are present in the Queen Charlotte Basin year round, it may be challenging to mitigate potential impacts on these acoustically sensitive animals.
Major funding for SPLASH has been provided by the Canada’s Department of Fisheries and Oceans, the U.S. National Marine Fisheries Service, the U.S. National Marine Sanctuary Program, Mexico’s Department of the Environment, and several private research foundations.