Category: General natural history

This year I’m teaching Ecology for the second time. It is a field-intensive course: we have all day on Fridays to meet outside the classroom and do something outdoors. Most people understand that hands-on experiences are the best way to learn, whether the subject matter is field-based or computer-based (such as working with software for statistical analyses), and part of my job this semester is to provide as many diverse experiential activities as I can for my students. As I am a marine biologist by training and inclination the course is biased towards marine ecology, but I’m doing my best to include terrestrial activities as well.

Today we visited the Younger Lagoon Reserve on the Long Marine Lab campus, to participate in the ongoing habitat restoration project. We were met by Beth Howard, the reserve manager, and Tim Brown, the reserve steward, who gave us a brief history of the reserve and the conservation work going on there.

We are standing in a plot that had very recently (as in within the last week) been planted with young grasses. The reserve staff, volunteers, and student interns collect seeds from local populations of native plants, germinate and grow them up in the greenhouse, and then plant them the following spring. The idea is that in a few years the larger scrub plants, such as coyote bush and sticky monkey flower, will outcompete the non-native weeds and the plant community will more or less take care of itself. The annual flowering plants should re-seed and repopulate the area at the end of the season.

Tim, as the reserve steward, designed this bit of the reserve. The areas within the polygons are to be planted with flowering annuals, while the spaces between polygons are to be filled with perennial grasses. To make seed gathering easier, we were told to plant in patches, resulting in medium-sized patches of several plants of one species grouped together.

In addition to helping plant upwards of 1500 plants today, we got to see how last year’s plants are doing! I’m proud to report that they have filled in beautifully and grown a lot:

Not all the vegetation in the right side of the photo was the stuff that we planted last year. Some of it was weeds. The reserve workers are about to shift from planting mode to weeding mode, to remove as many weeds as possible before they have a chance to flower and set seed.

When it was time to start the actual planting, we were shown how to make holes and insert the baby plants.

The dibbler is a nifty tool that makes holes in the ground. You clear off the layer of mulch, shove the dibbler into the soil, and wiggle it around, making a perfectly round hole. The plants are grown in cone-tainers, that not-so-coincidentally are the exact same size and shape as the holes made by the dibbler. I asked Beth, and she confirmed that the dibbler and cone-tainers are made by the same company. Once the dibbler has made the hole you remove a plant from a cone-tainer, stick it in the hole, tamp down the soil around it, and replace the mulch.

We were instructed to place the holes 18″ apart, and not in a strict grid pattern. The goal is to restore a natural setting, not create a formal garden. After the instructions we all got to play in the dirt.

In addition to planting flowering annuals in a couple of the polygons, we also did this:

After our work in the field we went across the marine lab to Younger Lagoon. It rained on us for a while, and we sheltered under the lean-to and looked out over the lagoon. It’s beautiful even in the rain.

This red-winged blackbird was loudly staking his claim to a bit of territory. He never showed off his red epaulettes, though. Another bird was replying from the top of a cypress tree a short distance away. The back-and-forth went on for about five minutes, before one of the birds flew off.

For the first time I got to hike the trail that parallels the east side of Younger Lagoon. We didn’t go down onto the beach, but I was able to see a perspective of the large rock at the mouth of the lagoon that I’d never looked on before.

Does anybody else see the profile of Abraham Lincoln in this rock?

Today my students and I visited the Monterey Bay Salmon and Trout Project hatchery, to learn about local efforts to save the federally endangered coho salmon (Oncorhynchus kisutch). The coho is one of five species of Pacific salmon found on the coast of North America, the other four being the Chinook (O. tshawytscha), the chum (O. keta), the sockeye (O. nerka), and the pink (O. gorbuscha). The coho’s range extends in the North Pacific from northern Japan up along Russia, across the Aleutians, and down the coast of North America to the northern bit of Monterey Bay. In our area the coho return to their natal streams (Scott Creek, Big Creek, and occasionally the San Lorenzo River) during the winter rains in January and February.

The local population of coho make up an evolutionarily significant unit (ESU). This means that they are locally adapted to the extent that they are biologically and genetically distinct from other populations. For example, coho from Alaska, where they are much more common, cannot be successfully transplanted into our watershed because they are genetically programmed to spawn in the fall, the time of year when our streams are dry or disconnected from the ocean due to sand bars. So these fish aren’t just any old salmon. They have evolved to live in this particular watershed and as such are irreplaceable.

Our first stop of the morning was to the fish trap on Scott Creek. The weir, the structure that extends across the river in the photo below, traps fish that are swimming upstream. Once on the upstream side of the weir, the fish are directed into the cage, from which they can be removed so that fisheries biologists can collect life history data–species, sex, weight, length–before they are released to continue their journey upstream (if they are steelhead) or transported to the hatchery to be spawned (if they are coho).

No fish were in the trap when we got there this morning but our host, a NMFS biologist named Erick, told me that eight coho had been caught yesterday. We did see a pair of steelhead swimming in the water upstream of the weir. Anytime I see a fish out of water, I forget how difficult it is to find them when they’re in their natural habitat. The spots on a steelhead’s back blend in perfectly with the ripples of the water and the gravel of the stream bed.

Do you see two faintly reddish blurs in the photo above? Those are the fish. They are facing upstream, to the right. The larger fish on the top is the female.

After the visit to the fish trap on Scott creek we drove up to the hatchery, which is located along Big Creek. The hatchery’s day-to-day operations are run by a couple of people from MBSTP. During the busy seasons staff and interns from the NMFS lab in Santa Cruz work up there, too, so the little hatchery building gets quite crowded. We were fortunate to get to see pretty much all the steps involved in trying to return an endangered species from the brink of extinction.

Male salmon, called bucks, are held in pens outdoors. They can contribute more than one sperm donation in a season, just as in the wild a male can fertilize the eggs of more than one female. A buck is taken from the pen, sedated, and then is milted for his sperm. The milt is collected into a glass test-tube and kept dry; once the sperm make contact with fresh water they become activated, and there is a 30-second window during which they can fertilize eggs. Sperm can also be damaged by exposure to UV radiation, so the test tubes are always held in a closed hand. Back inside the hatchery building Erick takes a look at the sperm under a microscope to make sure they can swim properly.

Female salmon are called hens. Before eggs are taken the hens are anaesthetized and examined by palpation and ultrasound to confirm that their eggs are mature. A sample of ovarian fluid is taken and sent off to be tested for disease. When a hen passes the ripeness test she is sliced open to release her eggs into four metal basins.

A single female’s eggs are fertilized by the sperm of four males. The fisheries biologists keep a detailed matrix of who mates with whom, so that they can avoid additional inbreeding in a population of fish that has already undergone a genetic bottleneck. Milt that has been collected from broodstock males is placed over the eggs. Fertilization occurs once fresh water is added to the basin. The egg-sperm combination is swirled (“just like panning for gold,” Erick explained) for two minutes, then the eggs are rinsed and disinfected before being placed into a 100% humidity cold incubator held at 11°C.

The eggs remain in the incubator until the embryos have developed eyes. Then they are transferred into trays through which water flows. When they’ve absorbed most of their yolk sac they get placed into large indoor trays where they will be fed until they are big enough to go into the outdoor tanks. They’ll spend about a year in the outdoor tanks and should then be ready to undergo the process of smoltification, during which their physiology undergoes the alterations necessary for the transition to marine life.

When I took last year’s class to the hatchery we didn’t get to see much activity because there were so few fish returning due to the prolonged drought and low water in the creek. This year’s El Niño, which has brought rain, has also made it possible for the fish to get into the creeks. Coho are a 3-year species, so the fish returning this year were born in 2013. These fish outmigrated as smolts into drought conditions, and fortunately for them they return during a rainy year. Their progeny will outmigrate in 2017, hopefully into a strong upwelling which will produce lots of food. And when they return in 3-4 years, I hope that there is enough rain for their creek to flow.