Tag Archives: nimbus fish hatchery

The Bugs Were More Interesting Today, 10-15-18

DAY 10 OF MY VACATION.  I got up around 6:30 this morning, expecting to meet with an on-line friend, Dee, at the Nimbus Fish Hatchery. Dee had to cancel at the last minute because her dog got skunked, but I decided to go to the hatchery for a walk anyway.

There wasn’t much of anything at all to see there.  The migrating waterfowl haven’t arrived yet, and the salmon ladder wasn’t operating.  But I did get to see some of the salmon in the river; their humped backs appearing through the surface of the water here and there. I also got to see a few birds: California Gulls, Herring Gulls, Common Mergansers, and a female Belted Kingfisher rushing back and forth along the riverbank. There was a Great Egret walking along the netting on the top of the fish raceways, trying to find a way in, and it actually made it in somehow for a little while. As soon as the employees realized it was in the raceway, they opened gates and shooed it out again.  I’ve seen Green Herons (who are much smaller and can hide more easily) inside the raceways just gorging on fish.  That Great Egret could’ve taken a lot of the larger fish if it hadn’t been seen as early as it was.

CLICK HERE for the album of photos.

The fish in the raceways “know” that when a shadow moves along the side of their enclosure, food is probably coming, so they go crazy – jumping and splashing, opening their mouths for fish-food to fall into. There are buckets along the raceways filled with food you can take to the fish, and every now and then, a truck goes by spewing food out of the side of it like a leaf-blower.

In a sort of gully/barrow pit next to the raceway area there were several Mallards, a Great Blue Heron and a Snowy Egret wading through the rocks and water looking for tidbits. I was able to get quite a few photos of the heron, but actually, some of the insects in the area were more interesting. I found a Mayfly, several ladybeetle nymphs and pupa cases, a large gravid praying mantis, and Green Stinkbugs, some of their eggs and several nymphs in different stages of development.

As I was leaving, I got a glimpse of a beaver swimming on the edge of the bank but lost it when it ducked underwater.

At the Nimbus Fish Hatchery, 02-27-18

Around 7:30 I headed over to the Nimbus Fish Hatchery. This was going to be the last day they were going to do the Steelhead spawning, and I wanted to film some of that process for the naturalist students. When I got to the hatchery, nothing was open yet, so I walked the ground for a little while. It was 37º there, but the wind coming off the American River made it feel like 32º. Brrrr!

The visitor’s center opened up at 8:00, which is when the Steelhead spawning was advertised to start… But I was told that it was going to be delayed for an hour or so, so the process could be simulcast to grade schools in the area.

I didn’t want to just stand around for an hour and half, so I decided to brave the cold again and walk part of the trail instead. If nothing else, I could take some photos of that to share with my naturalist class.

Right around the visitor’s center there were lots of Brewer’s Blackbirds, and I also saw some Lesser Goldfinch, a House Finch, lots of House Sparrows and Golden-Crowned Sparrows, and several hummingbirds (Anna’s, I think).

On the river I saw lots of Common Goldeneye Ducks, Common Mergansers (more females than males), Canada Geese, a single Grayleg Goose, Herring Gulls, Ring-Billed Gulls, and California Gulls.

The best find by the river was being able to see gulls and Double-Crested Cormorants lining up on a wire that goes from one side of the river to another. I’m not sure what it’s used for, but the winch-end of the wire is on the hatchery’s side. The cormorants get their “nuptial crests” – that stand out like bushy eyebrows over their eyes — during the breeding season, and we’re right at the beginning of that now. Most of the crests you see are black (which generally means that the cormorant is a resident of California), but occasionally you’ll see one with white crests which generally means they’re migrating down into our area from more northerly regions, like Alaska. I saw one with white crests today. That was a first for me.

CLICK HERE to see the album of photos.

The salmon raceways were empty, even the water had been drained out; but on the trout side of the facility, there were Rainbow Trout in various stages of development in every raceway.

Caught inside the structure, too, were a couple of Black-Crowned Night Herons. They must’ve gotten in when someone opened and the forgot to shut the entrance gate – and then got trapped in there when the place was locked up again. They were looking pretty panicked. The only way to get them out would be to open the gates again and shoo them toward the open door. But opening the gates means other fish-eating birds can get into the raceways, too… A conundrum.

By the time I got back to the visitors center, they were halfway through the filming of the Steelhead spawning, and I didn’t want to interrupt that, so I left.

On my way home, I passed right by the American River Bend Park, so I stopped there for a few minutes just to see if I could spot the Great Horned Owl on her nest that I saw the last time I was there. Yep. She was there, sitting on her nest, dozing away. Because the nest is so high and the lighting around it is so bad, I can’t get very good photos of it, but I took a few anyway.

In the same area, I also saw a mule deer in the distance, several Mourning Doves, a few Northern Flickers, Spotted Towhees, Oak Titmice, and an Audubon’s Warbler. It looks like stands of Stinging Nettles are starting to come again – which may be a bad thing for hikers and campers, but is a good thing for Red Admiral butterflies who lay their eggs on the plants, and whose caterpillars depend on them for food and protection. I only stayed at the park for about 30 minutes and didn’t walk any of the trails.

Vacation Day #13: Nimbus Fish Hatchery

DAY THIRTEEN OF MY FALL VACATION… I got up a little before 7:00 am and headed out to the Nimbus Fish Hatchery. I knew they had the salmon gate open, so I wanted to see if I could spot any of them; and I wanted to see if the migrating birds were around there yet. The weatherpeople forecast clouds and rain for today, but when I went out it was mostly sunny and around 53º… and it stayed nice all the while I was outside.

At the hatchery, there weren’t hardly any waterfowl.  I saw some Mallards, a couple of Great Blue Herons and some Great Egrets, along with several Double Crested Cormorants but no other ducks or geese. There were a lot of different kinds of sparrows out there, though, and I saw House Sparrows, White-Crowned Sparrows, and Golden-Crowned Sparrows. There were also Acorn Woodpeckers around and lots of Starlings. I saw one Starling poking its head out of its nesting cavity… which was too near the Acorn Woodpeckers, and they were fussing about it. The big surprise was seeing a small flock of Cedar Waxwings.

A one place along the trail there was a huge fig tree, and the leaves were dotted with clusters of Assassin Bug egg cases. Yikes!  The fig was just starting to get fruit on it. Coffeeberry trees along the route were burgeoning with berries, though, just in time for the Waxwings (who eat berries almost exclusively).

The raceways were full of trout and salmon. When I was walking around the trout raceways, one of the rangers came up to me and handed me a big (16 oz) cup filled with fish food so I could feed the fry.  “You’re the first kid we’ve had through here today,” he said as he handed me the cup.  Hah! He said there were currently over 3-million trout in the raceways (everything from fingerlings to adults), and in another month or so they’d be pulling them all out and depositing them in tanker trucks to take to the lakes and ponds all over the area. None of the trout form there go into the rivers.

The fish are used to being fed by hand (or by another truck that goes between the raceways and blows food at them like a huge leaf-blower). Whenever I leaned in over the side of the raceways to look at them, they’d all rush to the edge and splash around expecting food. When you toss food to them they all attack it at the same time and it’s gone within seconds.

Also in the raceways were about four Green Herons. The raceways are completely surrounded and covered by chain link fencing, but someone must’ve left a door open and the smart herons rushed in.  Once they’re in there it’s hard to get them out, but there are literally millions of fish for them to eat, so it’s not like they’d starve.

When I went over to the salmon side of the hatchery, I was surprised to find that they were actually collecting and “spawning” the Chinook Salmon that were coming up the ladder. I didn’t think they were doing that until December, so it was a treat to be able to see it so early in the season.

Here are some pix: https://www.flickr.com/photos/mkhnaturalist/albums/72157686356492352

Video #1: https://youtu.be/6gf0-kdqX-w

Video #2: https://youtu.be/92TwnHBQsgU

When they bring the salmon up to take the eggs, they kill them (because they’re at the end of their life cycle anyway).  There was one hug female in the mix –- she must’ve weighed 40 to 50 pounds – and the rangers said she probably had 10,000 eggs in her belly. (A normal take is about 5,000 per female.) The bodies of the fish that are killed, are tagged and sent to Washington state where they’re used in dog food and made into fertilizer, so they’re “recycled” and not wasted.

I walked around the hatchery grounds and trails for about 3 ½ hours and then headed home.

Salmon Egg-Taking at the Nimbus Fish Hatchery

I was up at my normal time today, but instead of heading into the office in Woodland, I headed out to the Nimbus Fish Hatchery in Rancho Cordova to watch the first salmon egg-gathering session of the season.  It was about 47° outside when I got there.

CLICK HERE FOR PHOTOS AND VIDEOS

I wasn’t expecting a lot of fish to be in the ladder, because it’s so early in the season and this was the first time this year the eggs were being taken, so I was surprised to see part of the fish ladder full of huge thrashing fish.  I could also see the salmon moving along the shores of the river and jumping out of the water here and there.  It was neat!  Before the egg-gathering starts, the hatchery personnel close off the gate to the fish ladder (so they’re not inundated with fish) – and you can see the salmon coming up to the gate and banging on it because they’re so anxious to get up the ladder to spawn.  They can spawn in the river, but because the majority of them were raised in the hatchery, the majority of them try to come up the ladder.

Then they corral the salmon at the top of the ladder into a pool and push them toward the hatchery building with a moving wall.  When the fish come into the building, they’re given an electrical shock to get them quiet.  Then they’re lifted up into the spawning room where a group of scientists handle all the aspects of egg-gathering.  Personnel at the head of the line separate the males from the females, and separate the “ripe” females (those whose eggs are ready to harvest) from the “unripe” ones.  They can tell which is white by palpating the salmon’s stomach.  Sometimes, they’ll also squeeze the belly to see if some eggs squirt out.  The ripe ones go on to the egg-gathering table, and the unripe ones are shunted down a tube into raceways where they can stay until their eggs are ready.

Because the salmon will die immediately after spawning anyway – (unlike Steelhead which can be returned to the river after their eggs are taken) – the males and ripe females are then killed with a hammer.  There was a good deal of blood that went along with that, and some of the people who were watching the process – especially the small children – were upset by that.  All of the dead fish are put into bins, however, and their bodies are harvested for meat for the regional food closets, and leftovers that will go to make pet food and fertilizer.  So, all parts of the dead fish are used.

The ripe females are slit open and their eggs are hand-shoveled into white square spawning trays where their fertilized with sperm squeezed out of a male fish.  Then an iodine wash is added to kill and errant bacteria and the eggs are sent to the tanks in the back of the building to hatch and grow into fry. There was also a team of female scientists there who, before all the eggs were taken from the females, would take a small sample of the eggs and test them for diseases, check them for DNA to see where they came from (if they were wild or if they came from a hatchery), and check for viability.  It’s all soooo fascinating to watch.

CLICK HERE for a video I posted live on Facebook.

CLICK HERE for another longer video of the process.

 

New Year’s Day at the Nimbus Fish Hatchery

I left the house around 9:30 am to go walking at the Nimbus Fish Hatchery, and Marty left just a little bit after I did to attend a New Year’s party in Vallejo with friends.  There was very little traffic this New Year’s morning, so I got to the hatchery in no time.  There were some obnoxious people along the trail by the hatchery, but thankfully not too many.  There was one kid who had his dog on a leash; he was on one side of the trail and the dog was on the other so the leash was blocking the trail and no one could get past him.  I told him he’d better pick one side or the other because I wasn’t stopping… and he pouted but moved anyway.  Some people’s kids.  Sheesh!  Then I came across a small family group that had walked down to the water’s edge to watch the guys fishing along the bank, and instead of being considerate, they starting yelling and throwing rocks into the water to scare the fish off.  The fisherman just stared them down until they stopped.  I swear, some people leave their brains at home when they go outdoors…

Because there were so many fishermen around, there weren’t a great many birds in the area (except for the ubiquitous gulls who come to the waters outside the hatchery this time of year to eat all the dead salmon.)  One guy asked a ranger if he could down and take some of the dead salmon from the water, and the ranger told him, no; the dead fish were part of the ecosystem and helped to feed everything from mammals to invertebrates.  “I’m a mammal,” the guy complained.  “You don’t count,” the ranger said.  Hah!  Take that guy to the burn unit.

There were no fish in the fish ladders (which were running anyway).  The Steelhead will be coming up them in the next week or so, though.  I got photos of the gulls, some Buffleheads, Goldeneyes, Cormorants and Mergansers, then as I was walking out I noticed two egrets near the observation platform just above the gates in the river: a Great Egret and a Snow Egret.  I think I stood there or about 20 minutes just getting photos of them.  I had to shoot through TWO fences to get the shots, but thankfully a few of them turned out well.

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Watching Steelhead Eggs Get Gathered & Fertilized

I got up about 6:16 this morning, so I could get out the door a little after 7:00… and headed out to the Nimbus Fish Hatchery.  I wanted to see them gather the eggs from the Steelhead Trout.  I got there about 10 minutes before the process started, so one of the docent guys in the visitors’ center walked me through it and showed me all the key things I should look for when the fish were let in.  When the process started, it was just me and a woman with her two kids, and a couple of staffers watching it, so I was able to see everything really easily.  I got photos and some video… but I was shooting through a dirty glass wall most of the time, so the camera was having trouble focusing on what I wanted it to.

I’m glad I went to see the Steelhead eggs gathering rather than the Chinook Salmon egg gathering process.  When the salmon go through, they’re killed: smacked on the head with a hammer and gutted.  They’re going to die right after they spawn anyway, but the process sounded really bloody and brutal.  Steelhead, on the other hand, can spawn year after year, so the hatchery doesn’t kill them and instead puts them through a process that allows them to go back into the river after the eggs are gathered and fertilized.

The process starts outside of the hatchery building.  Fish come up the 260-foot ladder from the river and then go into a “crowding tank” which is about 12 feet wide and 60 feet long.  Once in the tank is closed off, a mechanical arm pushes the fish forward to a lifting tank on the outside of the hatchery building.  A gate on the side of the hatchery’s wall opens up, and the fish in the crowding tank swim into a “lift-tank” inside the building.  From this point, you watch the egg-gathering through a glass wall.

There’s a curling cable that goes down into the lift-tank, and it “anesthetizes” the fish with a low electrical charge.  Once the fish are calm, the tank rises and the handlers check each fish.  Rainbow trout (trout that haven’t gone to sea yet) were mixed in with some of the Steelheads, so they were put into a chute that sent them right back to the river.  The Steelheads are all checked to see who’s “ripe” and who isn’t.  The “unripe” fish are put into a run (outside) to hold them for a day or two to see if they can “ripen” before being returned to the river.  They don’t keep the Steelhead in the run for very long, because the fish don’t handle being confined well and can die of shock.

Ripe males and females are “tagged’ by cutting a notch in their tail, and separated into large pans by sex.  Inside the large pans is a mixture of mineral salts that also helps to keep the fish calm.  (When the fish are released back into the river, they sometimes turn around and come back up the ladder again.  The handlers can tell if they’ve already seen and counted the fish by whether or not there’s a notch cut into its tail.) Even with the electrical zap and the chemical bath, some of the fish were still really spry.  The docent said that the fish are really strong, and if they’re not handled properly, they can injure themselves or the handlers.  The salmon, especially, he said, are so tough that they’ve actually smacked the handlers hard enough to knock them out, split their lips open and and break their noses.

Then the females are taken out of the “girl pan”, one at a time, and one guy holds her while another guy uses a syringe to pump a little air into her belly.  The air pushes against the mass of eggs inside the mama fish and helps to push them out.  The handler squeezes out all of the remaining eggs, and then “burps” the female to get all the air bubbles out of her.  (If all of the air isn’t removed, then the fish can’t swim properly because she’d be too buoyant.)  She’s then turned over to a team of biologists who measure her, and take scale, blood, tissue and ovarian fluid samples for research purposes before she’s released down the chute into the river.  Her eggs are put into in a plastic pot, and then a male Steelhead is pulled out of the “boy pan”.  The handler squeezes the male’s belly to push out the milky sperm (“milt”) over the eggs, and the guy holding the pot stirs the eggs and milt together with his hand.  The male Steelhead goes to the biologists and then down the chute, while the guy holding the pan of now fertilized eggs carries the pan over to another guy who then moves the eggs to a tank with betadine-like stuff in the water to kill any microbes or diseases that might have been in the ovarian fluid.  After their betadine bath, they’re put in cylindrical clear-walled hatching tanks where the Steelhead eggs hatch into fry.

It was really neat to watch the process; they have it down so well that no one got in anyone’s way, and the fish were all processed quickly. Here are a couple of short videos:

Separating the Boys from the Girls video: http://youtu.be/1LdGvGnxC6c
Fertilizing the Eggs video: http://youtu.be/Jv0upLwFz04

The docent said that last year at this same time they would get about 26-30 pairs of Steelhead each time they did an egg-gathering round, and the rounds could continue on back-to-back for the whole day.  Today, because the river is so low, there were only 4 pairs of Steelhead in the first round (of fish that came up the ladder) and about 6 pair in the second round (that came out of the holding run)… and then the crowding tank was empty.  So egg-gathering this morning only took an hour.  Yikes!  He also noted that the hatchery releases about 4 million Chinook fry and 1 million Steelhead fry into the adjoining rivers each year… but their numbers will probably be lower this year because of the drought conditions.

 When I was done watching the egg-gathering process, I walked on the path along the American River and took some photos of the water birds out there.  Lots of cormorants, seagulls, and ducks… and one little Phoebe.  Awwww…  It was a fun morning!

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