Fish play an important role in water environments. They feed on nearly all types of plants and animals, they provide a home for other organisms such as bacteria and crustaceans, and they are eaten by many other types of animals, including many terrestrial species. Their vast numbers and diversity also contributes to their importance. Fish are the most abundant vertebrates in terms of both species and individuals. It is estimated that there are approximately 22,000 species of fish which make up about half of all species of vertebrates on earth—a little more than half of these species are marine (58%).
Coho Salmon & Steelhead Trout
Point Reyes National Seashore protects a portion of the watershed necessary to ensure the safe migration and spawning of coho salmon (Oncorhynchus kisutch) and steelhead trout (O. mykiss). This protection is necessary as both species have been directly impacted by human activities and development. Healthy creeks are one step toward maintaining and hopefully increasing their populations. Their true hope for survival lies in changing human attitudes, behaviors, and priorities.
Armed with chest waders and measuring sticks, National Park Service staff and volunteers brave streams swollen from the winter rains to survey for spawning coho and steelhead. They track spawners, carefully count carcasses, and take tissue samples for DNA analysis, providing valuable information to study the abundance and distribution of these fish. This is part of the work of the Coho and Steelhead Restoration Project.
When coho salmon and steelhead trout were placed on the threatened species list, the National Park Service initiated a five-year project to identify, evaluate, restore, and enhance coho and steelhead populations and their habitat within three West Marin parks, Point Reyes National Seashore, Golden Gate National Recreation Area, and Muir Woods National Monument. The Coho and Steelhead Restoration Project is focusing on Pine Gulch, Redwood, Olema, and Lagunitas creeks and their watersheds.
The project has the following six objectives:
To learn what may influence the reproductive success of coho and steelhead by looking at present stream conditions.
To investigate past stream conditions and how these have affected populations of salmon and steelhead.
To assess current coho salmon and steelhead abundance and distribution.
To develop and implement a plan for restoring and monitoring the fish and their habitat.
To inform the public and other resource managers.
To encourage community involvement through education and restoration of the watersheds.
The benefits of this program extend far beyond these salmonids. Healthy streams and riparian systems in West Marin will protect habitat for a myriad of other aquatic and land creatures such as river otters, California freshwater shrimp (an endangered species), California red-legged frogs (a threatened species) and migratory songbirds that nest in creekside bushes and shrubs.
The success of this ambitious program depends on the active participation of the public, local community conservation organizations, adjacent landowners, and public agencies. By working together, we will lay the groundwork for sustainable and healthy streams, riparian zones, and watersheds.
The Salmon Protection And Watershed Network (SPAWN) is a local non-profit organization that works to protect endangered salmon in the Lagunitas Watershed. SPAWN offers walks to view spawning salmon for the public and for school groups, in addition to offering seminars, training, and volunteer and internship opportunities.
From 2007 to 2012, Pacific Coast Science and Learning Center Science Communication Interns produced a series of podcasts, videos, and audio-slide shows exploring science from Bay Area national parks. Five of these The Natural Laboratory multimedia products focused on fish—two on white sharks, two on coho salmon, and one on tidewater gobies. View the videos or listen to the podcasts below. Visit our Multimedia Presentations: The Natural Laboratory page for additional videos and podcasts.
While spawning coho in Central California once numbered in the tens of thousands, estimates now put their numbers at fewer than 500. Learning about the coho population through monitoring helps researchers target efforts aimed at helping the coho recover. Fishery Biologist Mike Reichmuth and Intern Ben Atencio discuss our endangered coho salmon and how they are monitored in the Bay Area National Parks.
Casandra Brooks interviews Scot Anderson, a local researcher who has studied white sharks off of Point Reyes Seashore and at the Farallon Islands for more than two decades.
5 minutes, 5 seconds
The Natural Laboratory Podcast: New Findings about Great White Sharks of the North Pacific
A The Natural Laboratory podcast produced by the Pacific Coast Science and Learning Center in 2010 in which Casandra Brooks interviews Scot Anderson, a local researcher who has studied white sharks off of Point Reyes Seashore and at the Farallon Islands for more than two decades.
Credit / Author:
Casandra Brooks / Pacific Coast Science and Learning Center
This is the Natural Laboratory, a podcast exploring science for Bay Area National Parks. I'm Cassandra Brooks.
Today, I'm with Scot Anderson, a local researcher who's studied great white sharks here off Point Reyes Seashore and at the Farallons for more than two decades. In the fall of 2009, Anderson and his colleagues with Stanford University's Tagging of Pacific Predators Program, UC Davis and others published a paper on the sharks. Their study revealed new information about where the sharks travel to, how they spend their time, and showed that the shark population here off California's genetically different from great white shark populations throughout the world.
I sat down with Anderson to find out more about the study and what it tells us about these iconic and revered animals.
[Scot Anderson Interview]
Cassandra Brooks: Maybe you could tell me a little bit about what at typical day is like for you out in the field.
Scot Anderson: Yeah, okay, so a typical day, uh, going out looking for sharks, let's say, on the Farallon Island runs, we leave out of San Francisco, now, on a big sailboat called the Derek M. Baylis. It has this launch and we, uh, go to the island and we launch the launch and we work out of that for six hours on the water looking for sharks. Um, usually what we do is we put a decoy out that's about the size of a small sea lion and a small piece of whale blubber next to the boat, that's tied to the boat. And what that does is provides a area of scent around the boat that gets the sharks interested in sticking around. And then, if the shark comes around, we videotape them first, try to document what the shark looks like, who it is, and what their sex is, and then we go ahead and either tag them.
CB: How do you actually tag a great white shark?
SA: [cross talk] tag a white shark. [Brooks chuckles] Um, it sounds like it'd be a complicated process, but it's actually quite simple. You wait for the right moment, which is when the shark is at a 90-degree angle to you, swimming by the boat. So, then, the tag is on the end of a long pole and it has a harpoon-like dart on the end. Once it's embedded in the shark's skin, it's going to stay there until it finally pulls out, in a year to two years, or something like that.
CB: And during that year to two years, it's collecting data the whole time about where the shark is going and...?
SA: Yeah…okay so there's two kinds of tags we use. The first kind of tag is a satellite tag and that we put on the shark and then it...it records data, like, uh, the depth of the water, the temperature of the water, and light levels, and things like that. And that's on the shark until a pre-programmed date that it's, uh, released. When it releases, it floats to the surface and starts downloading data.
The other kind of tag's called an acoustic tag and, um, it makes a sound that's a signature sound for each individual shark, comes out to a number. If they swim within a quarter mile of the receiver, it logs them in. Now these receivers are placed on the bottom and we have one at Tomales Point, one at Point Reyes, two at the Farallons, and two at Año Nuevo.
CB: Wonderful, so people will just have these underwater devices that are just constantly picking up these pings that are individual to each shark, and, then, you know when they are there and when they are not there.
CB: I was hoping you could tell me a little bit about the recent study that was published in the Proceedings of the Royal Society. And you were co-author on this study.
SA: Well, it's a study that, sort of pulls together a lot of different kinds of data. And, so, what we did was we took DNA data and looked at that and what we found is that the sharks are very closely related. And then you start looking at where the sharks have migrated to and from and it's actually a...an area that's well deﬁned. They don't go much past Hawaii—maybe 500 miles beyond that—and they don't go past Midway, and they don't go north of in a line with Canada, and they are pretty much in this zone.
CB: But why do they even migrate as far as past Hawaii?
SA: So why do they go there?
SA: Well, that still remains a question to be answered. But it really looks like it has to do more with breeding than feeding, because this population, when they're on the coast, is feeding on an abundance of food. So, why would you go somewhere where there is very little food?
CB: You were talking that the study also shows that this population is genetically distinct. Does that...so it means that they’re not breeding with sharks from South Africa, obviously, or other areas...
SA: Right, yeah, because of the genetics, we know they're isolated up here and it's its own distinct population, so...
CB: And that seems like a very important finding in terms of understanding their role in the ecology here in the North Pacific.
SA: Yeah, you know, when you look at the role animals have in the environment, they're either going to be a producer or a consumer. Obviously, white sharks are apex predators; they're at the top of the game here. The role they play in the environment is...has yet to be totally understood, because we know they eat seals and sea lions—during certain times of year—and we know that they scavenge on dead whales and things and...but so do other animals. Whether they're actually, you know, keeping the environment healthy and all that, it's yet to be seen, but probably. They must play some role.
Looking out over the ocean from Tomales Point, it's surprising to think that great white sharks, among the most massive and mobile predators in the world, don't use the whole Pacific as their playground and that they don't mate with other white sharks in the world. Instead, they follow a strict and isolating migration path between California and the Hawaii region, which, as winter rapidly approaches, they are soon to embark on. Why, exactly, they make these vast migrations remains to be seen, but until then, Anderson and colleagues will be out every fall doing more observational and tagging studies.
With the Pacific Coast Science and Learning Center, I'm Cassandra Brooks.
Cassandra Brooks provides a report about the effort to relocate some endangered tidewater gobies to a lagoon in Tomales Bay State Park.
2 minutes, 26 seconds
The Natural Laboratory Podcast: White Sharks of the Northern Pacific
A The Natural Laboratory podcast produced by the Pacific Coast Science and Learning Center in 2008 in which John Cannon interviews Taylor Chapple, a graduate student at the University of California-Davis who has been studying sharks at the mouth of Tomales Bay.
Credit / Author:
John Cannon / Pacific Coast Science and Learning Center
The Natural Laboratory Podcast Transcript:
White Sharks of the Northern Pacific
John Cannon: This is The Natural Laboratory, a podcast exploring science for San Francisco Bay Area national parks. I'm John Cannon.
JC: There are worse places to live than the coast of Point Reyes National Seashore, 30 miles north of San Francisco, if you are a sea lion. [Sea lions can be heard barking in the background.] The cool waters support many species of fish, octopus, and squid that top the list of these noisy characters' favorite prey. And the weather is relatively nice, if you have a very layer of blubber and a fur coat that stays warm when it's wet. It's chilly at times, but rarely too hot There are lots of places to rest: sandy beaches, rocky outcroppings, and even the occasional weather buoy.
JC: But every fall, the waters around Point Reyes get a little more dangerous. From the open ocean, great white sharks make their way to the coast. They're on the hunt for food. And pinnipeds, the group that includes sea lions and their cousins, harbor seals and elephant seals, carry a nice ribbon of energy-packed blubber, making them an ideal source of nourishment for a hungry 1500-pound predator.
JC: I recently spent some time with a team of scientists studying sharks near the mouth of Tomales Bay at the northern tip of the park. I found out the great whites aren't always easy to find. And sometimes, they're preoccupied with other things. It was pretty clear that the first shark we saw wasn't at all concerned with us. So, we had to go after the shark.
Taylor Chapple: Um, yeah, so we just...we just had, basically, a pile of water that had some red color to it and I guess it was an attack.
JC: That's Taylor Chapple. He's a graduate student at the University of California-Davis and the group's leader here at Point Reyes. In four years studying sharks here most days each fall, this is the first evidence of an attack Chapple has seen out here. When the team first saw the blood in the water, they race the boat to the spot to find only a flash of fins in the bloody aftermath quickly dissipating in the churning water.
TC: [Unintelligible] was a sea lion 'cause the sea lions don’t float once they get chomped on. Elephant seals or harbor seals will float on the surface ‘cause they have a lot more blubber, but the sea lions, unfortunately, sink. So, we can’t really tell where the animal is [unintelligible] and it doesn’t bring the shark to the surface, obviously, if they don’t stay up.
JC: That's one of the challenges that all shark researchers run into. Unlike whales, sharks and other fish have gills and don't have to come to the surface to breathe. But, as this attack illustrates, it’s often where they come to find their air-breathing prey.
JC: So, to learn more about sharks, Chapple and his assistants have a few strategies to bring the sharks up from the depths.
TC: Sharks love Johnny Cash.
JC: While Cash’s crooning might not be the most effective or scientific tact, a sea lion-shaped decoy made of carpet stitched around the buoy usually does the trick. It sits bobbing in the water about 30 meters behind our stationary boat.
TC: And the idea is that we attract, you know, the shark to the surface just using that visual display. You know, we don't have to go through the whole process of chumming. We don’t do any chumming, or, you know, throwing blood or anything in the water.
JC: Instead, they rely on the shark's innate attraction to the decoy, an instinct hardwired into the shark's brain by millions of years of evolution. It's that instinct that tells the shark that this black object about four feet long with flippers and floating at the surface, just might make a tasty meal.
TC: So, once an animal comes up to the decoy, we shoot photos of it 'cause each of the dorsal fins of a white shark, the trailing edge of it is basically like a fingerprint so we can ID an individual start from that. So, we take photos of that and then reel the decoy towards the boat. As the decoy gets closer to the boat, we use an underwater video camera and take shots of the animal, trying to get sex and any more basically distinct markers on the animal. And once we feel like we have enough information that we can ID an individual, then we'll put a tag in.
JC: Those tags provide biologists with a host of information. When a tagged shark is in the area, a small receiver on the boat tips the team off to the fact that it is close, even if there's no evidence at the surface. And the receiver registers the tag's unique number, so Chapple can actually identify that individual shark. By correlating its number with photos and data from the past, you can tell how big that shark is, its sex, and the last time you saw it. Special satellite tags also provide scientists with information about the movements of sharks on a larger scale. These revelations allow Chapple and his colleagues to home in on the mysterious movements between areas like Point Reyes and places far out in the Pacific where many of these sharks aggregate. This effort involves researchers who study other species in the ecosystem with similar monitors placed at various locations along the coast.
TC: And what’s nice is that these monitors are present for a number of different species. So, they have these monitors for salmon, for sturgeon, for sharks, and for, you know, a whole list of other species. So, in a collaboration, we can all get information about our animals being at somebody else's array of stations. So, you don't...we don't necessarily have to put 5000 of these listening stations around. We can just collaborate with other researchers.
JC: The data collected by all of these researchers will be compiled into a much larger ten-year undertaking known as the Census of Marine Life. This project aims to catalog the quote diversity and abundance of life in the oceans unquote, looking piece by piece at this grand web of ocean life.
JC: For now, Chapple will continue researching the strand of that web he knows the best: the white sharks of the Northern Pacific. And right on cue, a sail-shaped dorsal fin appears next to the decoy. This shark, an untagged female just a few feet shorter than the boat we're on is inquisitive, but it's not the violent eruption of activity I'd expected. Chapple says this cautious behavior is more typical than the bite first, ask questions later approach that white sharks seem to be notorious for.
TC: You know, it's not this horrific attack scene like you, you know, you see in the movies or they put on the Discovery Channel. It's usually pretty...pretty mellow, like, she came up once just past the decoy, and then did a circle under water and then came up just kind of nudged it to check it out. Very rarely do you get them that they come up and they, you know, attack the decoy or even...even bite it. And it's pretty rare that that happens. It's usually really...uh...kind of a mellow interaction. I guess as mellow as you can be being 16 feet long.
JC: But mellow is not the word to describe the great white's effect on its environment, and us. As an apex predator, this species is a critical component of a functioning and healthy ocean ecosystem. The World Conservation Union has listed white sharks as vulnerable and they're likely impacted by climate change, overfishing, and other changes brought about by humankind. But the truth is: we know very few basic details about their lives—where they go to breed, the size of the population, and how long they live, to name just a few. So, we're just beginning to understand what must be done to protect this remarkable ocean hunter. These questions only make the research that Chapple and others have taken on that much more important as we begin to uncover the extent of our own interdependence with the world's oceans. For the Pacific Coast Science and Learning Center at Point Reyes National Seashore, I'm John Cannon.
The Natural Laboratory Podcast: Tracking the Coho Salmon
A The Natural Laboratory podcast produced by the Pacific Coast Science and Learning Center in 2008 in which Kelly Reeves interviews Michael Reichmuth, a fresh water fisheries biologist at Point Reyes National Seashore about endangered salmon that reside in the streams that flow through the park.
Credit / Author:
Kelly Reeves / Pacific Coast Science and Learning Center
The Natural Laboratory Podcast Transcript:
Tracking the Coho Salmon
Kelly Reeves: This is The Natural Laboratory, a podcast exploring science for Bay Area National Parks. Today, I learn how biologists keep an eye on the endangered salmon that live a quiet life in the streams that flow through the parks.
Casey Del Real is standing knee-deep in a narrow creek. He's holding a metal rod into the water and he's about to shoot 175 volts of electric current through it.
Casey Del Real: If you stick your hands in the water, you will be shocked.
KR: Casey is a certified electrofisher. For him, electrofishing is not sitting back shocking the water and then calmly collecting hundreds of belly-up fish.
Unidentified fisheries biologists: There you go, there you go. Oh, a big one! Two big ones! Nice!
KR: It's a bit more vigorous.
[Unintelligible talk in the background.]
KR: When Casey stuns the fish, the shock only slows the fish to, maybe, a fast crawl. A flash of silver on the creek surface is all you see. Netters on either side of him stab the water to scoop up the fish. The netter plunks each fish into a white holding bucket.
Unidentified fisheries biologist: What did we get here?
Second unidentified fisheries biologist: Uh, it looks like one coho and a couple steelhead.
KR: Which one is the coho?
Second unidentified fisheries biologist: It is the smaller one right here.
KR: The coho is silver is big dots on its side. Casey grabs for it in the bucket. The coho's head sticks out from his fist about an inch. Like all newborns, its eyes seem a little too big for the rest of its body.
Unidentified fisheries biologist: Oh, oh, right there!
KR: Coho salmon are endangered in this area of California and steelhead trout are threatened. National Park Service biologists track these two types of fish, coho especially.
Michael Reichmuth: Coho would be a good indicator of the overall health the system. Not only does coho use the creeks, but also uses the estuary and all parts of the system, all the way from the tributaries all the way down to the mouth.
KR: That's Michael Reichmuth. He leads the crew that monitors stream fish in San Francisco Bay Area national parks.
MR: Coho have a three-year life cycle and they are born in the springtime and then they rear in the summertime.
KR: Right now, the fish are hanging out in the creek, gaining weight so that springtime next year they can make a break for the ocean. When they returned 18 months later, they spawn eggs and die. Mike and his crew keep track of all these life stages. They're in the creeks pretty much year-round.
MR: So, it's pretty intense.
KR: Park Service biologists have monitored stream fish since 1997. But, since the coho salmon have a three-year life cycle, biologists have so far only tracked six cohorts from birth to death. From so few cohorts, they can’t really say have the coho are doing. But Mike says they do know that more coho need to survive before they are no longer considered endangered.
MR: Ideally, we’d like to keep monitoring the populations until they get to recovery. To have a viable population you need around 2,000 spawners a year. So, we're actually well below what we would need to actually consider the fish stable. So, we have a lot to work for so I think we're going to be monitoring for quite a long time.
KR: Mike say that, in 2007, more coho one-year-olds survived the winter to swim to the ocean than normal, probably because few storms swept the coast this winter.
[Unintelligible talk in the background.]
KR: Mike measures and weighs all the fish netted today. At the end of the day, he pours the fish swimming the recovery pocket back into their home. Mike, Casey, and their crew will be electrofishing twice a week until October and then they'll start observing adults from the class of 2005 returned to their home creek to spawn. This is Kelly Reeves from the Pacific Coast Science and Learning Center.
Science Behind the Scenery: Coho Salmon and Steelhead Trout Video
The seventh part of the ten-part Science Behind the Scenery documentary featuring hydrologist Brannon Ketcham talking about coho salmon and steelhead trout and efforts to protect their riparian habitat at Point Reyes National Seashore.
Pacific Coast Science and Learning Center Research Project Summaries
From 2006 to 2009, Pacific Coast Science and Learning Center (PCSLC) communication interns assisted scientists conducting research through the PCSLC and the San Francisco Bay Area Inventory & Monitoring Network to produce a series of Resource Project Summaries, two of which were about fish at Point Reyes. These two-page summaries provide information about the questions that the researchers hoped to answer, details about the project and methods, and the results of the research projects in a way that is easy to understand.
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