MARTINEZ, Calif. – This is a tale of a mysterious Steelhead fish that was recently observed swimming upstream in no more than a few inches of water within a stretch of Alhambra Creek near Ward Street last week.
A sharing of the video posted on the Martinez Tribune’s Facebook page with local fishery experts generated a range of perspectives and theories about what brought this creature to this time and place, and views on the wider topic of the health of Bay Area watersheds that are critical in this fish’s survival.
Gordon Becker, a senior scientist with CEMAR, an organization focused on rehabilitating California coastal streams, suggested the fish might “just be lost,” or that it came from the Alhambra Creek watershed.
Napa and Sonoma watersheds are where populations of steelhead are more plentiful and commonly seen. In contrast, the presence of one here reflects the fish’s opportunistic nature to take advantage of local conditions.
“It could have spawned in the watershed and has returned (as part of its journey from the bay),’’ he said.
Michelle Leicester, a District Fisheries Biologist with the California Department of Fish & Wildlfe’s Bay/Delta Region serving Alameda, Contra Costa and Santa Clara counties, believed the fish was able to enter the stream because the recent storms provided sufficient flow volumes to allow the fish to swim upstream until it reached the location where it was filmed.
“By that time, the flows had dropped because the rain had stopped, trapping the fish where it was,’’ she said. “If you look at the video closely you will notice the fish is holding in a small depression in the concrete apron of the bridge where some water had accumulated.’’
“Fish need to have their bodies submerged in enough water that they can propel themselves forward using resistance against the water generated by the side-to-side movement of their tail fins,’’ Leceister continued.
If there is no water to provide that resistance, fish may merely “flop around” as they are unable to swim.
November to April is the peak period where this fish would be expected to be seen making its run.
However, Becker noted there has been a long-term decline and distribution of Steelhead due to a variety factors. Land use and development near watersheds and flow restrictions, as well as the persistent drought, have together exasperated the life cycle of the steelhead.
“They are in a perilous state,’’ said Gordon of its plight.
As a result, the steelhead has been listed as a “threatened’’ species under the federal Endangered Species Act.
But one thing that could be said of this discovery is it reflects the fish’s determination to beat the odds.
“Steelheads are a hearty bunch,’’ said Gordon, and it does what is necessary to adapt to its surroundings by seeking out pools of water where it can.
An extremely low survival rate of 2 percent awaits the fry, the name for young Steelhead fish, as they make the return journey from the ocean. But provided they make it to the ocean, Becker said they have a chance to come back.
Aiding this species in its pursuits are the recent rains. But as Leicester and Becker observed, an abundance of rain in a short period can be a doubled edged for these hearty creatures, especially when other factors come into play.
Leicester said the streams that respond quickly and abruptly to rain events are called “flashy” because their water levels rise quickly and drop quickly. Streams are fed by underground water tables, which in many cases allow them to be flowing even when it’s not raining.
When humans pave over the ground with asphalt and buildings, rain cannot percolate and recharge these water tables. Instead it is directed into storm drains and adds to the problem of “flashiness” by causing higher flood peaks and more rapid return to base flow levels.
The recent years of drought have caused the water tables to become even more depleted, especially in urban areas where buildings, concrete and asphalt surfaces prevent groundwater recharge during the rainy season.
“This means streams are now ‘flashier’ than normal, and don’t flow as much or for as long, and the risk of fish being stranded like this is even greater than usual,’’ Leicester said.
Becker noted the concern over “blasting’’ that occurs when creeks are flowing fast due to much rain. This causes the Steelhead to be carried to the bay before they are ready.
“When they go to the ocean too small, then it makes it hard to return.
So care for the watersheds by the local community and public works planners is essential if there is to be successful Steelhead restoration in area creeks, Becker said.
To see this local Steelhead in action, visit the Martinez Tribune Facebook page at https://www.facebook.com/981589728559198/videos/1268333933218108/.