Tag: migration

Author SuzannePosted on Categories Habitats, Water, WildlifeTags , , , ,

Salmon lose diversity in managed rivers, reducing resilience to environmental change

NOAA Fisheries West Coast Region, EurekAlert!

The manipulation of rivers in California is jeopardizing the resilience of native Chinook salmon. It compresses their migration timing to the point that they crowd their habitats. They may miss the best window for entering the ocean and growing into adults, new research shows.

The good news is that even small steps to improve their access to habitat and restore natural flows could boost their survival.

The curtailment of high winter river flows by dams means that they no longer provide the cue for the smallest fish to begin their migration to the ocean. The loss of wetlands in the Sacramento-San Joaquin Delta leaves little of the refuge habitat they need to grow along the way. Meanwhile later-migrating fish suffer from rising summer temperatures that reduce their survival even though they migrate at a larger size.

Fish that begin their migration in mid-spring are the ones that survive best and dominate adult salmon returns to rivers such as the Stanislaus. These results were cited in a study published this week in Global Change Biology. Flow alteration and habitat loss have in effect homogenized the survival opportunities of salmon in this highly managed river system, researchers wrote.

That diminishes what is called the “portfolio effect,” where a diversity of salmon migration strategies help the fish cope with changing environmental conditions. This is similar to how diversified investments help buffer your financial portfolio against jolts in the stock market. Chinook salmon in California evolved diverse migration timing to handle the wide variation in climate, ocean, and river conditions in the Central Valley region. This is also important as climate change and rapidly changing, “whiplash weather” patterns further alter the picture.

“You never know what’s going to be a winning strategy in the future,” said Anna Sturrock of the University of California, Davis, and lead author of the research that also included scientists from several other agencies and universities. “Keeping options on the table is the best strategy, but that is not what we see happening.”

The research also found that the lower flows released from dams tend to reduce fish production. This is likely due to reduced access to floodplain habitats and lower food production in rivers.

Read more at https://www.eurekalert.org/pub_releases/2019-12/nfwc-sld121219.php

Author SuzannePosted on Categories Habitats, Sonoma CoastTags , ,

Ocean heat wave brought 67 rare, warm-water species to North Coast

Mary Callahan, THE PRESS DEMOCRAT

An extended ocean heat wave that spurred a series of ecological anomalies off the Northern California coast — including toxic algae, mass sea lion strandings and the collapse of the bull kelp forest — also promoted the northward migration of an unprecedented number of southern, warm-water species.

Sixty-seven rare, warm-water creatures, including 37 whose presence has never been documented so far north, were found in the region and points poleward, according to a UC Davis Bodega Marine Laboratory study published Tuesday in “Scientific Reports.” Everything from bottlenose dolphins to two kinds of sea turtles to barnacles and small sea snails were present during the study period between 2014 and early 2017.

One colorless, tiny snail cousin, the striated sea butterfly, hadn’t previously been seen north of the tip of Baja California. It turned up in sampling nets collecting whatever critters might be floating past the Bodega Bay lab, said lead author Eric Sanford, a UC Davis professor of ecology and evolution.

Similarly, pelagic red crabs — four still alive at the lab — that came ashore at Salmon Creek Beach in January 2017 normally would have been closer to Baja, he said. Also found in the bay was the molted shell of a spiny lobster more commonplace in Baja.

With the planet and the ocean warming, the recent, extended marine heat wave “provides a glimpse of what the Northern California coast might look like in the future,” as species move toward cooler environments to survive, Sanford said.

“We’re basically seeing these communities change before our eyes as more southern species become part of these communities,” he said. “That’s pretty dramatic.”

Read more at https://www.pressdemocrat.com/news/9376990-181/ocean-heat-wave-brought-67

Author SuzannePosted on Categories Climate Change & Energy, WildlifeTags , ,

Butterfly migration is a Thanksgiving tradition on Sonoma Coast

Gaye LeBaron, THE PRESS DEMOCRAT
There was a wire service news story in the paper a couple of weeks ago about monarch butterflies.
It seems that in late October, some of the eastern monarchs, which are supposed to migrate south to Mexico each fall, were still hanging out in Canada’s Point Pelee National Park on a northern flank of Lake Erie. They should have been “on the road,” so to speak, at least six weeks earlier.
This is scary stuff for the lepidopterists who study butterflies and are already concerned about the effects of climate change on the insects.
Monarchs, they know, don’t do well when the temperature drops below 50 degrees — the muscles that make them flutter apparently stiffen in the cold.
Some consider this another reason to declare the big orange and black butterflies that are the undisputed sovereigns of the butterfly world an endangered species. Some will go further, taking this new glitch in the ecosystem as a warning that the apocalypse draws closer. The optimists say, let’s wait and see what happens next year before we panic.
I am not versed in lepidoptery or entomology. But I do know a little something about monarchs — western monarchs, that is — the ones who live west of the Rocky Mountains in both the U.S. and Canada.
Their southbound migration route hugs the Pacific Coast and can go all the way to Mexico every winter. They have a lot of choices, in California’s temperate coastal climes, as to where to spend their winters.
Read more at: Gaye LeBaron: Butterfly migration is a Thanksgiving tradition on Sonoma Coast

Author SuzannePosted on Categories Sonoma Coast, WildlifeTags ,

Tail end of gray whale migration happening off Sonoma, Mendocino coasts in April, May, June

Jeanne A. Jackson, THE PRESS DEMOCRAT
Just off our coastline, more than 20,000 gray whales travel thousands of miles on their great migration. In autumn, they begin their journey from their feeding grounds in the Arctic Circle to their birthing, mating and nursery waters in the lagoons off Baja California. It’s a trip of five to seven thousand miles, one-way. And the whales do not eat until they return to the Arctic in the spring.
The first to leave the Arctic are the pregnant females. They are followed by those gray whales who will be mating. Those whales not mature enough to mate, will then follow, though some will linger off the coast.
While in the warm waters off Baja, mother whales give birth to their calves. Each mother whale births one calf. The mothers and calves will stay in the lagoons for the calves to gain enough strength to swim the thousands of miles north. The mothers will feed their calves with their rich, calorie-dense milk. They nurse their babies as human mothers nurse their young. Gray whale bodies have many similarities to human bodies.
The first whales to leave Baja and head north in late winter are the newly pregnant females. They swim fast and hard, as they need to reach their feeding ground where they will be eating for two.
The last to leave Baja are the mother/calf pairs, and that is what is occurring now. April, May and early June are the perfect times to whale watch, as the mother/calf pairs are closer to shore due to the current, and the whales come up more often for their offspring to breathe.
Read more at: Tail end of gray whale migration happening off Sonoma, Mendocino coasts in April, May, June | The Press Democrat

Author SuzannePosted on Categories WildlifeTags , , , , Leave a comment on Watch the return of the steelhead at Lake Sonoma

Watch the return of the steelhead at Lake Sonoma

Meg McConahey, THE PRESS DEMOCRAT
The stunning steelhead trout are returning to the Warm Springs Dam Hatchery and the public is invited to come on down for the homecoming.
The 7th Annual Lake Sonoma Steelhead Festival on Feb. 7 is a chance to see these native beauties up close in a celebratory atmosphere that includes special activities, hatchery tours, live music and food and drink.
And except for the refreshments, which this year includes wines from Dry Creek wineries, everything is free.
The highlight of the event is watching the spawning fish, some of which grow to a robust two feet in length, as they make their way up a ladder of pools from Dry Creek to the hatchery, an elevation of 37 feet.
“The focus is to educate people about wildlife conservation, environmental protection and propagation of a threatened species,” said Harry Bosworth, the president of the Friends of Lake Sonoma, which hosts the event along with the U.S. Army Corps of Engineers, the California Department of Fish & Wildlife and the Sonoma County Water Agency.
Read more via Watch the return of the steelhead at Lake | The Press Democrat.