Status of humpback whales and human impacts

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Citation

Cascadia Research. 2007. Status of humpback whales and human impacts. Final Programmatic Report to US Fish and Wildlife Foundation for project #2003-0170-019. 18p.

Executive summary

This report summarizes overall SPLASH results completed through the end of 2006 as well as reporting on the human impact assessment funded by NFWF. SPLASH is an international collaborative research program on the abundances, population structure, and potential human impacts on humpback whales in the North Pacific involving more than 50 research groups and 300 researchers. The National Fish and Wildlife Foundation provided two years of support to SPLASH which filled some key gaps in funding. This report summarizes findings of both the overall SPLASH photo-ID effort including the results of matching and analysis from the first three seasons of SPLASH effort, and three different measures of human impacts and health based on analysis of photographs of the tailstock, flank, and flukes of whales. SPLASH field effort was conducted at all known feeding and wintering areas for humpback whales in the North Pacific and consisted of five field seasons, three winter breeding seasons (Winter 2004, 2005, and 2006) and two summer feeding seasons (Summer 2004 and 2005). Identifications of over 10,000 individual humpback whales (some matching still underway) represent the largest photo-ID catalog of whales conducted. Over 5,000 skin samples were collected over the five seasons. Comparison of SPLASH identification photographs collected in Winter 2004, Summer 2005, and Winter 2005 yielded 5,348 different humpback whales. There were almost 500 migrations of individual whales documented from wintering grounds in 2004 and 2005 to the summer feeding areas in 2004. This represents the largest and most complete examination of humpback whale migrations in the North Pacific and revealed a far more complex pattern of movements than had been documented previously. For the first time, migrations were documented between feeding areas off Russia and all three Asian wintering areas. These initial data also suggest that there was an additional wintering area for humpback whales not previously documented between Asia and Hawaii. Human impacts and other injuries were documented from photographs of the tailstock, flanks, and flukes of whales. Incidence of entanglement of humpback whales was primarily documented from the examination of scarring on the tailstock. This was the first systematic effort to quantify entanglement rates across an ocean basin and results to date indicate significant variation among North Pacific areas. Southeastern Alaska produced the largest sample of high quality images and 50% of whales showed signs of entanglement. This was higher than some of the other North Pacific feeding areas and is similar to estimates for the Gulf of Maine, where entanglement is a management concern. Small sample sizes were a limitation for some of the other feeding areas and inclusion of images from the later SPLASH years (2005 and 2006) will allow improved estimates. Examination of the flanks and flukes of humpback whales also provided important information on human injuries and health status. Analysis of flanks provided measurements of serious injuries including ship strikes and these varied by region with some of the coastal feeding areas (i.e., those closer to ship traffic) showing higher rates. Analysis of flanks also provided important insights into seasonal and regional patterns in body and skin condition, as well as incidence of various skin disorders. Body condition did steadily improve during the feeding season but skin condition deteriorated. Injuries on flukes revealed higher rates of scars from killer whale attacks in some areas and also revealed a geographic pattern in the incidence of non-killer whale-related injuries that was similar to that seen in the analysis of flanks. SPLASH sampling to date has been extremely successful and exceeded expectations. Even though matching is not yet completed it has provided important new information on the status of humpback whales in the North Pacific. Analysis of health and human impacts on humpback whales from visual examination of flanks, tailstocks, and flukes was also more successful than anticipated. While all aspects of SPLASH are going extremely well, funding is still needed to complete the analysis of SPLASH data including completion of matching, analysis of skin samples collected, and completion of the analysis for human impacts and health assessment for the final seasons of SPLASH. SPLASH will be requesting a third year of funding from NFWF (only the first two years of our three-year proposal were funded) to help complete this work. 

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