by Jim Steele
Gray whales are remarkably resilient animals. Eastern Pacific whales make a round-trip of 10,000 miles between their warm winter waters around Baja California to give birth, then feed in the cold Bering and Chukchi Seas from May thru September, gaining enough energy that must sustain them for the rest of the year. Unlike other whales, gray whales have specialized on suctioning the sea floor for food, preferring sand dwelling amphipods.
While experts suggest the optimal whale population has historically been between 18,000 and 22,000 individuals, their coastal migrations made them easy targets for whalers in the late 1800s, reducing their population to somewhere between just 250 and 5000 individuals. After receiving protection by the International Whaling Commission in 1947, they quickly rebounded and by 1995 were removed from US Endangered Species List. Despite climate change, by 2018 gray whale numbers increased to 27,000+ and the International Union for the Conservation of Nature considered them a species of Least Concern.
Why such increases in whale abundances? The lack of Bering Sea ice between 2012 and 2018 had allowed more photosynthesis. Stanford researchers reported a 57% increase in phytoplankton in the past 2 decades. That increased the food that sank to feed organisms on the sea floor (the benthos). In addition, less sea ice and a longer open-water season, enabled gray whales to spend more time feeding in the Chukchi and Bering Sea, gaining the energy needed for their 7-8 month fast, while enduring migration and reproduction.
Nonetheless, whenever gray whales approached peak abundances that may have exceeded their carrying capacity, they experienced sudden population crashes in 1987–1989, 1999–2000 and 2019–202 that NOAA has called an “Unusual Mortality Event” (illustration C). All the evidence suggests gray whales experience the classic ecological “boom and bust” dynamics (exemplified by the relationship between the lynx and snowshoe hare that’s taught in every 8th grade science class). The whales’ main prey (ampeliscid amphipods) can only feed a limited number of whales. As the whale populations increased beyond that level, they “eat themselves out of house and home”, the prey species crashes followed by whale numbers quickly crashing.
To counter the acknowledged positive effects of global warming, a recent paper (Stewart 2023) was compelled to push an unsupported narrative that global warming, not abundant whales, had reduced the ampeliscid amphipod prey. This led to numerous click-bait media headlines spreading misinformation about the gray whale deaths.
The bottom graphic highlights (red circles) the 2 main feeding hotspots that almost all gray whales now depend on. It is interesting to note that during the low sea levels of the last ice age, those hotspots were high and dry and relegated to Arctic tundra just 8-10,000 years ago. As sea levels rose, these hotspots became shallow seas with depths mostly less that 50 meters. It is that shallowness that allows more food to sink from the surface to the benthos before bacteria can decompose it, thus nurturing an abundance of sea floor organisms. In addition, the nourishment carried by the 3 major northbound currents further maintains these hotspots.
Stewart (2023) acknowledged that the loss of Bering Sea ice has perhaps enabled gray whales populations to grow beyond their pre-whaling maximums. However, apparently to grift the government climate crisis funding, he also offered a very contradictory narrative blaming global warming and less ice for reducing the whales’ prey. Despite research showing that less ice increased phytoplankton by 57% in 2 decades, Stewart reiterated to numerous media outlets that “With less ice, you get less algae, which is worse for the gray whale prey”.
Stewart (2023) was alluding to an unproven hypothesis, previously pushed by his co-author, that global warming reduces sea-ice-algae, algae that only grows on the bottom of sea ice. Climate alarmists have pushed the unsupported narrative for a decade that sea-ice-algae provides the critical food for the benthos food web. Click-bait media like ScienceNews headlined “Sea ice algae drive the Arctic food web”. What those grifters fail to share with the public is sea-ice-algae only contributes on average a meager 3% of all Arctic production, compared to the 97% provided by increasing phytoplankton where sea ice melts.
Furthermore, sea-ice-algae requires sunlight, and thick multi-year sea ice reduces photosynthesis. Due to the loss of multi-year ice, more transparent first year ice has nearly doubled since 1980, which increases sea-ice-algae production.
Finally, in their desperate attempt to link whale deaths to a climate crisis, Stewart (2023) cherry-picked the fact that less ice can change the speed of ocean currents and erode the sediments that large amphipods prefer. However, Stewart does not share that abundant amphipods prevent such erosion. Ampeliscid amphipods build mucus-lined tubes in the sand. As their density increases, individual tubes coalesce to form a mat that prevent currents from eroding away the sediments and thus preserving a stable environment for more abundant amphipods.
Yet again, it is the growing population of hungry gray whales that bulldoze those mats, reducing amphipod abundance, that enhance a classic natural boom and bust dynamic!