05-19-17

The Salmon Blog: Marin’s Steelhead fry doubled in length in one month.

They grow up so fast: In early April, Steelhead fry were around 30-35mm when SPAWN biologists begin counting them.

SPAWN’s primary research  objective is to assess the population size of smolts out-migrating from the San Geronimo Creek Watershed. During this study, other data points of interest include monitoring the salmonids in the early stages of their life cycle and understanding how other species, like crayfish and lamprey, use the watershed.

Decades of salmon research have determined the survival of the andromous fish in their freshwater stage is a make or break point  for survival of the species. During salmonids freshwater life history, the quality and availability of prey in the ecosystem affects their growth and survival. An ecosystem that offers an abundance of prey, allows for all genetic diversity in a population to compete and more successfully adapt to environmental changes.

Salmon are visual predators and will target invertebrates floating by in the water. In their parr lifestage, research shows salmonids establish bottom feeding territories, meaning whatever flows their way is fair game. Most often, the choicest prey items have been shown to be plankton like, crab larvae, copepods or amphipods, followed by the second-best option of terrestrial insects.  This Spring, and abundance of prey options has resulted in some healthy salmonid parr in the San Geronimo Creek watershed.

The graph below shows a month’s growth for 2017 Steelhead fry on San Geronimo Creek.

In the first week of the study, the vast majority of the young of the year were in the 30 to 35 millimeter size class. Within a week, resarchers were finding the majority of fish had moved into the next size class. Salmonids begin schooling as fry. If fry are reaching schooling stage and moving at the same rate through the watershed, one could hypothesize it’s the same age group gaining a size class of weight week to week. By the final week of the study, majority of the young of the year were documented to have doubled in size. There was also a marked reappearance of fish within the30-35mm size class, indicating these fish were born from redds laid later in the spawning season.

Baby salmon are much like Labrador retrievers and will try eating whatever looks good and fits in their mouth. At first, this range is limited to small zooplankton. Eventually they graduated to larger plankton. As a fish gets larger and faster, it will be begin pursuing larger and larger terrestrial insects. This Spring, there have been a plethora of prey items for the young of the year.

Time shall tell whether the abundance of insects will give the young of the year a fin up in becoming healthy sea-bound smolts next Spring.

Swim On!

 

About the author: Neely Evanoff is Salmon Protection and Watershed Network (SPAWN)’s salmonid research coordinator working on a research fellowship to study and document the endangered Coho Salmon and threatened Steelhead populations within Marin’s largest watershed. Neely is available for questions at: neely@tirn.net.

Interested in helping protect Coho Salmon? Become a member, donate, or volunteer! SPAWN fields a variety of programs centered around species monitoring, habitat restoration and community education.

 

 

05-12-17

The Salmon Blog: April 2017 Smolt Monitoring Update

In April, Smolt Monitoring got underway for 2017 in the Lagunitas Creek Watershed in Marin County, CA.

 

SPAWN biologists were able to safely enter the creek on April 17th after mid-month rainstorms blew out the net. All smolt data reported was measured 17 April – 30 April 2017. Abiotic data represents averages for the entire 30 days of April.

For the month of April:

Averages for the month:

     Stream temperature: 12 C

     Air Temperature: 22 C

     Rainfall: 6.83 inches

     Max stream flow: 1,032 cfs

     Min stream flow: 8.67 cfs

     Average coho weight: 105.4 g

     Average coho length: 114.5 mm

* Total Salmonid takes: 397 *

–Coho: 252 –Steelhead: 10

“Take” defined by the Endangered Species Act means to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect, or to attempt to engage in any such conduct.

397 times a fish was captured in our net in April, although only 262 new salmonids were counted. The other 145 account for recapture counts.

In April 2016, 334 new coho smolts were recorded. This year we have only counted 252 coho smolts. We suspect that the 5 inches of rain early in the month kept us out of the creek and helped a lot of fish make a break for it.

Swim on!

 About the author: Neely Evanoff is Salmon Protection and Watershed Network (SPAWN)’s salmonid research coordinator working on a research fellowship to study and document the endangered Coho Salmon and threatened Steelhead populations within Marin’s largest watershed. Neely is available for questions at: neely@tirn.net.

 

Interested in helping protect Coho Salmon? Become a member, donate, or volunteer! SPAWN fields a variety of programs centered around species monitoring, habitat restoration and community education.

 

 

05-12-17

The Salmon Blog: Juvenile Salmonid Identification 101

It is easy to differentiate adult salmonids, however as juveniles salmonids look similar.

 

Pictured are two adult salmonid species commonly seen in the San Geronimo Creek Watershed. To the left are Coho salmon and above are Steelhead trout. The terms “trout” and “salmon” refer to different life strategies.  These fish are members of the same genus, Oncorhynchus. Members of the same genus are genetically similar. Visual cues are easy with adult salmonids because Coho have a vivid red streak and the adult Steelhead are distinctively more spotted and lighter in color.

When Oncorhynchus fry wiggle out of their nest, they are almost identical.

Both Coho salmon and Steelhead trout evolved in cold, coastal streams. Both species are born in freshwater and in the first few months of their life, lead similar life styles that involve wiggling out of rocky nests and eating. While coloration of the salmonid fry have not changed, the species evolved to specialize in different environments overtime. Because of this, salmonid fry develop into parr with distinctive behavior based on the species. Behavioral differences include schooling, feeding and hiding behaviors. These behaviors are endocrinology based (dictated by hormones).

Like in humans, the thyroid is responsible  for hormonal activities. Numerous studies on fish, including Coho salmon specifically, have shown thyroid activity is directly linked to behavioral changes in fish such as salinity preference, and changes in swimming patterns. The fish thyroid is also reported to mandate the coloration of a fish at different life stages. As Coho and Steelhead evolved in differing environments, the thyroid evolved to cue differing depositions of melanin laterally in the fish, resulting in distinctive parr marks. Researchers noted the cyclic activities of Onchrynuchus thyroids peak in the Spring time (this is possibly cued by more light exposure from longer days). Consequently, as young salmonids ingest a larger range of nutrients, and their hormones dictate differential behavior and coloration, researchers can begin to tell the species apart.

With a bit of the science background under our belt, let’s begin to discern which salmonid is which.

To understand fish identification, start with general fish anatomy. When a key directs you to look at the caudal fin, it means the tail. When directions say to examine the parr marks, this is indicating a coloration.

When looking at a fish…what are you actually looking at?

It is important to know which fins are which on a fish.

On the simplified fish below, major fins are marked.  Please take note of where the dorsal and anal fins are located. These fins are especially important in salmonid identification.

The table below outlines the physical features of Coho and Steelhead.

	Coho	Steelhead
Dorsal Fin	No spots.	Spotted.
Caudal Fin	Slightly forked to squared tail. If present, few spots limited to upper caudal.	Slightly forked to squared tail. If present, spots on both upper and lower caudal fins.
Anal Fin	Sickle shape with a white leading edge. 13-17 fin rays.	Fin is even length. 8-12 fin rays.
Parr Marks	Narrow oval shaped bars with wider intraspaces between the bars.	Wide, oval bars along swim line.
Swim Line	Silvery, pale line.	Distinctively pink or red line.
Spot Characteristics	Usually few spots that only present on the upper sides. Spots are only black only and will be much smaller than the eye pupil. Spots will be a round or irregular in shape	Many sports present covering most of sides and the spots are only black. The spots will be much smaller than pupil of eye and round or irregular in shape

Why are the dorsal and anal fins important? On salmonids, these fins are species-specific and consistent from juvenile life stages through adulthood.

Based on the graph above, what is the fish pictured below?

SPAWN biologists filmed this tiny fry and the picture is an outtake of the footage.

The parr marks, dorsal fin, swim line, and caudal fin are all still undeveloped. This could be either salmonid! Closer inspection of the photo reveals the anal fin has an even edge…but there are thirteen fin rays. Because there are more than twelve fin rays, this is definitely a Coho fry who will eventually developed a sickle-shaped anal fin and other Coho characteristics as it becomes a parr.

As the fish grow, so do their features and they become easier to identify.

Based on the graph above, which of these parr pictured is a Coho and which is a Steelhead?

Having trouble?  The picture below illustrates the sickle-shaped anal fin of a Coho parr in comparison to the straight-edged anal fin on a Steelhead parr. Steelhead parr will present a spotted dorsal fin while Coho parr have no spots.

Look again- can you tell the fish apart now?

A Coho parr is on the left and the Steelhead parr is on the right. The Steelhead has spots on it’s dorsal fin, more spotting in general and an even-edged anal fin. The most tell-tale sign is the pink swim line. The Coho parr on the left has no spots on the dorsal fin and a white leading edge on it’s sickle-shaped anal fin.

Remember: the Endangered Species Act (which is Federal Law) prohibits harassment of any salmonids. If you see a fish in your backyard creek, look and do not touch! Hopefully this document will help you identify what you are viewing.

Swim on!

 

About the author: Neely Evanoff is Salmon Protection and Watershed Network (SPAWN)’s salmonid research coordinator working on a research fellowship to study and document the endangered Coho Salmon and threatened Steelhead populations within Marin’s largest watershed. Neely is available for questions at: neely@tirn.net.

Interested in helping protect Coho Salmon? Become a member, donate, or volunteer! SPAWN fields a variety of programs centered around species monitoring, habitat restoration and community education.

 

 

 

05-05-17

The Salmon Blog: What happens during smolt monitoring?

What do SPAWN biologists do every morning down by the creek?

The Daily Process

Step One: Step up the station!

At the monitoring station, the storage cooler doubles as a table for the scale. We also have a BioMark to check for fish PIT tags, a tray to measure fish length, nets, bubblers, buckets, and a clipboard with our data sheet.

Step Two: Retrieve the fish from the live trap!

All present species are gently sorted into collection buckets based on length.

Step Three: Count all non-smolts first*

(all the fish born this year).

A staff biologists will call out the species and size of fish, and then that fish is relocated from the white or gray collection bucket to one of two black buckets. Black buckets are the final bucket color in the process. One black bucket goes upstream and the other will deliver fish downstream. All non-smolt salmonids are sent downstream after being counted.

Non-salmonids such as three-spine stickleback and California Golden Roaches may be interspersed during this data round-up as well. They are always released downstream.

*If any non-fish species (Crayfish, Salamanders, bullfrogs ect.) are in the trap, they are immediately documented and released before any fish are counted.

Step Four: Count the smolts.

Research assistant, Neely, is pictured on a day she partnered with MMWD to help count smolts on Lagunitas Creek. SPAWN follows the same monitoring protocol as MMWD.

The Smolt Counting Process:

Fishy fact: Biologists rotate every 10 fish for accuracy and cold fingers. ><(((°>

The biologist handling the fish will call out: species, fork length (mm), weight (g), fish condition, if a PIT tag is present, what the mark ID is/if present, and whether it’s a new or recapture and the corresponding photo number.

The volunteer citizen scientist on duty for the morning records this info.

Fish we have never caught before are recorded as “New (N)” and given a fin clip. New fish go in the upstream black bucket to mix with the greater out-migrating population of smolts.

Fish that are re-captures, as marked by a fin clip, are recorded as “R” and moved to the downstream black bucket. These fish will continue on their way to sea, downstream of the trap.

Fishy fact: For each fish, the whole measuring process takes about 30 seconds. ><(((°>

During smolt monitoring season, biologists will encounter each individual smolt twice: once when it is a “new” fish and a second time when it is a “recapture.” A fish is never captured more than two times because a recaptured fish is released downstream to go on its hungry, merry way towards Tomales Bay. In Tomales Bay, the salmonids undergo a physiological change from being freshwater fish to saltwater fish.

Smolt monitoring is conducted as a part of salmon monitoring recovery plans all over the United States. The process is designed to not harm any fish while ensuring scientists can work to understand and save the species.

Swim on!

About the author: Neely Evanoff is Salmon Protection and Watershed Network (SPAWN)’s salmonid research coordinator working on a research fellowship to study and document the endangered Coho Salmon and threatened Steelhead populations within Marin’s largest watershed. She is available for questions at: neely@tirn.net.

Interested in helping protect Coho Salmon? Become a member, donate, or volunteer! SPAWN fields a variety of programs centered around species monitoring, habitat restoration and community education.

 

 

04-28-17
The Salmon Blog: Why Bubbles Are Important to Fish

When fish are taken out of their natural habitat, a bubbler is added. A bubbler is a machine with a porous stone that sits in the water, tethered to an aerator by at long rubber tube.

Bubblers= aerators.

They add oxygen to an aquatic environment. What happens when a fish is in a small, enclosed environment, like a bucket, is they run out of oxygen.

Bubbles 101

Basic understanding of how fish breathe: Oxygen dissolved in water goes into a fish and out comes carbon dioxide. The CO2 is absorbs into the surrounding water and eventually dissipates into the atmosphere through aeration (bubbles!) An air bubble rising through water is simultaneously dissolving oxygen into the water and absorbing CO2 as it reaches the surface. A bubble popping at the surface is releasing CO2 into the atmosphere.

When aerators are on, they will try to keep oxygen levels at normal conditions.In a stream or creek, a lot more processes are at work incorporating dissolved oxygen into the ecosystem. In our case, leaving a ton of fish in a bucket of still water is risky! Adding a bubbler allows fish to breath normally while they are processed for the study.

In summary, an aerator is to a fish what a snorkel is to humans: a consist supply of breathable oxygen.

 

Swim On!

About the author: Neely Evanoff is Salmon Protection and Watershed Network (SPAWN)’s salmonid research coordinator working on a research fellowship to study and document the endangered Coho Salmon and threatened Steelhead populations within Marin’s largest watershed. Neely is available for questions at: neely@tirn.net.

Interested in helping protect Coho Salmon? Become a member, donate, or volunteer! SPAWN fields a variety of programs centered around species monitoring, habitat restoration and community education.

 

 

 

04-21-17

The Salmon Blog: …Fyke Net?

This post is about the gear SPAWN’s fisheries biologists uses to conduct a mark recapture study on the smolt population of San Geronimo Creek Watershed.

A Run-down of the Gear:

SPAWN’s fyke trap consists of:

•      a 9 x 4 ft bag net

•      two wing walls (wooden frames covered with hardware cloth)

•      three ropes

•      three PVC pipes

•      six t-posts

•      a live trap (pvc box covered in mesh).

 

It takes about five hours to set up!

A fkye net is a type of fishing gear. It is a net in the shape of a bag. The bottom of the bag (net) is anchored to the bottom of a stream bed and the top of the net is suspend open.

Fyke nets are commonly used by biologists to capture coastal and euryhaline species all over the world. The system is great because it causes minimal impact on by-catch (non-target species) and is not destructive to surrounding environment.

As the picture shows: the mouth of the net is flanked on one side by wing walls connected to the creek bank. On the other side of the net, a low rock wall extends out about two feet, stopping short of the opposite bank. Allowing stream flow around the net is an important part of the mark recapture method fisheries biologists use to assess a population. Individuals in a population have to be “voluntarily” caught. Allowing stream flow around the rig enables any determined species to swim around our fish trap. This fishing trap design does direct most of the stream flow into the mouth of the net. The water current, and all accompanying creatures, travel to the back of the net and where the rig ends with a live trap box. The live trap box is made of PVC pipe and mesh.

Every morning for eight weeks, SPAWN biologists check the species present in the live trap box.

Swim On!

About the author: Neely Evanoff is Salmon Protection and Watershed Network (SPAWN)’s salmonid research coordinator working on a research fellowship to study and document the endangered Coho Salmon and threatened Steelhead populations within Marin’s largest watershed. Neely is available for questions at: neely@tirn.net.

Interested in helping protect Coho Salmon? Become a member, donate, or volunteer! SPAWN fields a variety of programs centered around species monitoring, habitat restoration and community education.

 

 

 

04/14/2017

The Salmon Blog: The Great Smolt Migration

All the metaphors about the majestic salmon’s journey are true. Each salmon lives a Homeric odyssey that begins with modestly eating freshwater zooplankton and quickly escalates into an orca-dodging, fishing net-eluding adult pilgrimage to nutrient-rich arctic waters. A salmon makes this trek only to return home to it’s natal stream, fat and extra delicious through the same dangers, in the hope it’s offspring can manage the same trip in the next year.

Every Spring, a new batch of one year old salmonids begin their epic seaward migration.

Biologists document the out-migration of salmonids as a baseline measurement to know how many successfully return to spawn.

In an ideal salmon world, all the fish leaving this Spring 2017 will complete their life cycle by spawning in Winter 2019. In reality, the difference between the population of fish that is going to sea this Spring and the portion of that population that will return in eighteen months is termed “escapement.”

Salmon Protection and Watershed Network (SPAWN) began it’s 2017 smolt monitoring in mid- April. For eight weeks, fisheries biologists and citizen scientists will collect data on the smolts. The data is crucial in monitoring the health of the population. Smolt counts tell biologists how the previous spawning class fared at sea, the health of the smolts as they have occupied the streams and through statistical analysis, indicates how many fish are using the habitat as a whole.
For more than a decade SPAWN has monitored the out-migration of smolts in Marin County’s San Geronimo Creek Watershed.  The tributaries of San Geronimo Creek, within the Lagunitas Creek Watershed, have been documented to support at least thirty percent of redds in the whole watershed.

The Lagunitas Creek Watershed is important to the state of California because it supports one of the largest remaining populations of endangered, wild coho salmon and threatened steelhead. The NOAA Recovery Plan, designed to aid the recovery of California salmonid populations, delineates the importance of Lagunitas Creek to the health of the state’s population. It is important to document changes in the salmonid population, through programs like SPAWN’s Smolt Monitoring, in order to evaluate the recovery plans effectiveness over time.

SPAWN’s objective is to measure juvenile abundance spatially and temporally throughout in San Geronimo Creek and establish a baseline for how habitat restoration efforts are protecting and improving the population.

Swim On!

 

About the Author: Neely is Salmon Protection and Watershed Network (SPAWN)’s salmonid research coordinator working on a research fellowship to study and document the endangered Coho Salmon and threatened Steelhead populations within Marin’s largest watershed. Neely is available for questions at: neely@tirn.net.

Interested in helping protect Coho Salmon? Become a member, donate, or volunteer! SPAWN fields a variety of programs centered around species monitoring, habitat restoration and community education.