A new publication has just come out, highlighting SR3’s health assessment of endangered whales on both coasts. SR3’s Dr. Holly Fearnbach collaborated with colleagues from NOAA’s Southwest Fisheries Science Center, New England Aquarium, Woods Hole Oceanographic Institution and Southall Environmental Associates in a paper published today in the high-impact scientific journal Current Biology, titled “Decreasing body lengths in North Atlantic right whales” (read the paper here). The study used aerial images spanning 20 years, collected from both crewed aircraft and remotely operated drones, to estimate body size and evaluate growth trends of the critically endangered North Atlantic right whales (NARW) off New England. NARWs currently number < 400 individuals, with declining abundance attributed in part to human-induced impacts such vessel strikes and entanglement in fishing gear. The study found that entanglements in fishing gear are also associated with shorter whales and that body lengths have been decreasing since 1981. The smaller body sizes have likely contributed to reduced calving success and population decline.
This finding of stunted right whales is remarkably similar to the results from our primary research on salmon-eating Resident killer whales off the Pacific Coast. In recent years, SR3 and colleagues have documented decreased adult body size in both endangered Southern and Northern resident killer whales, specifically for whales that grew in periods of low Chinook salmon abundance (read a recent paper here). Although the causes of this stunted growth are different for right and killer whales, the studies in combination highlight the severity of sub-lethal stressors, and indicate the need for additional management protections if these vulnerable populations are to recover.
Read reaction to the new paper in the New York Timeshere.
Photographs of North Atlantic right whales taken using non-invasive drones. Left photo shows the distinctive callosity patterns on the head, which are used to identify individuals and link measurements to known age. Right photo shows a whale in elongated surfacing orientation – images like this were measured to estimate length and monitor growth (note the scarring near the tail stock from a previous entanglement in fishing gear). Photographs by John Durban (NOAA) and Holly Fearnbach (SR3), authorized by NMFS research permit #17355.