Why there were so few blue whale sightings last year? Habitat compression
index could help to predict whale entanglements?… and save whale watch operators
gasoline money?
"Krill density was very low off much of the West Coast in 2019,
The 2020 State of the California Current report introduces a new ecological
indicator known as the “habitat compression index.” It reflects how warm
offshore waters run up against cold, deeper waters that well up near the coast.
The result is a narrow, “compressed” band of coastal ocean with cool,
productive waters that draw fish and their predators together.
Other recent research
<https://www.fisheries.noaa.gov/feature-story/blob-research-reveals-environmental-effects-shut-down-fishing-and-hiked-whale>
found that during the Blob years, the compressed habitat brought humpback
whales closer to shore to feed on booming numbers of anchovy. That put many
whales in the same waters where Dungeness crab fishermen set their traps, and
record numbers of whales became entangled in the fishing lines.
The habitat compression index will provide a running barometer of how offshore
heat is affecting nearshore waters and the species that depend on them. “We
will continue to study this metric in relation to other indicators in hopes of
understanding why coastal impacts in recent years have been so severe,” the
report says."
shirley johnson
thusone@xxxxxxx
