snorkeling methods - pnamp · post-survey visibility score rodgers ... grease pencil; knee and...

Western Division AFS Methods Review Workshop

"How many different ways is this method implemented?"

April 15, 2013

Snorkeling Methods

Table of Contents

Basic Snorkel Survey Methods

General Guidance – Basic Snorkel Survey Procedures 2

Colville Confederated Tribes – Snorkel Survey Methodology 4

Nez Perce Tribe – Snorkeling Methods 7

ISEMP - Snorkeling 8

SRFB - Estimating Instream Juvenile Salmonid Abundance Using Snorkeling 11

ISEMP - Snorkel Herding 13

SRFB - Detecting Fish Species Assemblages Using Backpack Electrofishing or Snorkeling 14

General Guidance - Mark-Recapture Estimates from Snorkeling Data 16

General Guidance - Estimating Fish Total Length Underwater 17

Comparison Tables 18

General Guidance - Basic Snorkel Survey Procedures

2

MM.org ID 136

Monitoring Entity or Program General Guidance

Method Name Basic Snorkel Survey Procedures

Method Owner Jennifer O'Neal

Citation Author O'Neal, J.S.

Year 2007

Citation Title Basic Snorkel Survey Procedures

Citation URL http://www.stateofthesalmon.org/fieldprotocols/downloads/SFPH_p10.pdf

Citation Publisher American Fisheries Society

Objective/Purpose/Metrics Relative and total abundance, fish distribution, presence/absence surveys, species assemblages (i.e., diversity), some stock characteristics (e.g., length estimation), and habitat use, information on individual or group movement, behavior, and habitat associations. Snorkel surveys can be combined with other methods such as sonar and tools such as geographic information systems (GIS) to generate three-dimensional maps of habitat use by fish species. Calculating population estimates can be done with mark-re-sight techniques.

Site Assessment - Weather Weather conditions should be recorded on the datasheet

Site Assessment - Water Temperature

Temperature should be between 10°C and 18°C for daytime survey, and less than 10°C or greater than 18°C for night survey (1 h after sunset)

Site Assessment - Visibility The minimum recommended visibility for surveys is 1.5 m (P. Roni, NOAA Fisheries, personal communication). Visibility during typical summer base-flow periods is often much greater. Snorkelers can evaluate clarity by using a silhouette of a salmonid with parr marks and spots, as described in Thurow (1994). A surveyor should approach the silhouette until the parr marks are clearly visible and then move away from the silhouette until the marks cannot be distinguished. The average of these two distances provides the water visibility (Thurow 1994).

Site Assessment - Depth Minimum recommended water depth for successful surveys is 20 cm

Post-survey Visibility Score Rodgers (2002) recommends ranking turbidity at each reach surveyed. Data can then be segregated for precision based on visibility. Rank underwater visibility of each pool on a scale of 0 to 3 where: 0 = not snorkelable due to an extremely high amount of hiding cover or zero water visibility; 1 = high amount of hiding cover or poor water clarity; 2 = moderate amount of hiding cover or moderate water clarity neither of which were thought to impede accurate fish counts; and 3 = little hiding cover and good water clarity.

Equipment For daytime surveys (water temperature greater than 9°C): Full neoprene wet suit (6.4 mm) or dry suit with knee pads, preferably black or blue or brown; Wet suit hood; Neoprene gloves; Neoprene socks; Wading boots with felt soles; Fins (can be useful in large systems when surveys must be conducted downstream); Mask with side window to increase visibility; Snorkel; Extra mask and snorkel for remote reaches; Data recorders such as a dive slate scroll (Ogden 1977) or a plastic cuff (10-cm PVC pipe in 20-cm lengths will work and can be secured with surgical tubing [Helfman 1983]); Grease pencil; Knee and elbow pads (for turbulent or shallow streams); Wet suit cement or Aquaseal® for repairing suits; Thermometer; Small halogen light; Canteen; Food; First-aid kit; Mobile phone and/or radio for emergency contact; Data forms; Measuring tape; Flagging. For nighttime surveys or daytime surveys where water temperature is less than 10°C: Everything listed above and the following: Dry suit (required) (should not have valves if possible); Adequate insulation under dry suit; Handheld halogen dive lights (a red filter can be helpful for reducing fish disturbance; filters can be made from red Plexiglas)

General Guidance - Basic Snorkel Survey Procedures

3

Survey Step-by-step

For preselected sample reaches, field crews should use GPS units and maps, aerial photos, or landmarks such as road

bridges or trail crossings to find the sample reach location (Rodgers 2002). If sample reaches are on private land,

landowner permission must be granted before the reach is accessed (Rodgers 2003). Before conducting a field survey,

available information should be collected on species that are likely to be encountered. Where snorkelers expect to find

protected species or species listed under the Endangered Species Act, they should avoid fish spawning areas. Snorkelers

should not touch or otherwise disturb protected fish while conducting surveys. The sampling team should record the

reach location information, weather conditions, water temperature, and water visibility at the start of the day and

several times throughout the day. Each unit sampled should be classified by type and assigned a unique number (Dolloff

et al. 1993). Rodgers (2002) recommends ranking turbidity at each reach surveyed. Data can then be segregated for

precision based on visibility. Considerations in field sampling include the size of the water body, which will affect the

number of snorkelers needed for the survey and the direction of the survey, and the objective of the study. Surveying in

the upstream direction is the most effective technique for small streams where this is feasible. Most salmonids hold

position facing the current, so upstream sampling is less likely to cause disturbance (Thurow 1994). Steelhead tend to

hold close to the bottom of the stream and quickly seek cover if they detect a disturbance. Upon entering the water,

observers should survey the bottom for any trout that may quickly take cover, as opposed to starting with other species,

such as coho salmon O. kisutch, that are more resistant to disturbance (Dolloff et al. 1993). Movements should be

controlled and sudden movements should be avoided to reduce disturbance to fish. Fish are counted as the snorkeler

passes them to reduce double counting. In larger systems, upstream counts may not be possible; in these cases

snorkelers may conduct counts while floating downstream and remaining as motionless as possible (although some

swimming may be required to maintain lane position relative to other snorkelers). The number of observers needed to

complete the survey is dependent upon water clarity, the size of the stream or river system, and the objectives of the

study. Thurow (1994) recommends using enough snorkelers to complete the survey in a single pass. It is recommended

that one surveyor be used for streams less than 2 m bank-full width, two surveyors be used for 2–5 m bank-full width,

and more than two surveyors should be used in places greater than 5 m bankfull width. During the survey, any

impediments to observation, such as deep water, turbidity, or significant cover elements, should be noted (Dolloff et al.,

1993). For smaller streams in which one observer can see the entire channel width, Thurow (1994) recommends

proceeding in a zigzag pattern across the channel to see both sides, especially in the margins of the streams where small

fish will hold in slow water areas. Other areas that deserve intense scrutiny are eddies behind logs and boulders and

underneath logjams and undercut banks. For these surveys, the surveyor generally proceeds upstream, against the

current. If two observers are employed (due to stream/river size, water clarity, or habitat complexity), the observers

should remain adjacent to one another and move at the same speed. Observers should mentally divide the channel into

“lanes” in which each observer will look for fish and only count fish that pass within his/her snorkeling lane (Thurow

1994). If two observers are used, each surveyor should be in the middle of the channel looking towards the bank to

cover his/her lane. If more than two surveyors are used, middle lanes will have to be designated. Diagrams of these

configurations are shown in Thurow (1994). In these situations, snorkelers should frequently check on each other for

safety and to maintain position. Data on fish species and size-class can be collected and recorded on a PVC cuff or diver’s

slate and later transferred to a data sheet or database. Data can also be called out to an onshore observer who records

the information on a data sheet or in a digital data collector. After completing the count of fish, observers should

measure the surface area of the snorkeled unit. The total length of the unit should be recorded as well as the width at

three or more equally spaced intervals. Maximum pool depth should be recorded (Rodgers 2002) if additional habitat

surveys are not being conducted. The surface area can be calculated by multiplying reach length by average width or by

summing the surface area of individual habitat units, which the crew can measure as it moves upstream. Density of fish

is typically expressed as the number of fish per square meter.

The Colville Confederated Tribes – Snorkel Survey Methodology

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MM.org ID 98

Monitoring Entity or Program The Colville Confederated Tribes

Method Name Snorkel Survey Methodology

Method Owner John Arterburn

Citation Author John Arterburn & Keith Kistler

Year 2007

Citation Title Okanogan Monitoring and Evaluation Program, Field Manual, Snorkel Survey Methodology

Citation URL https://www.monitoringmethods.org/Method/DownloadDescription/98

Citation Publisher The Colville Confederated Tribes

Objective/Purpose/Metrics Estimating the abundance, species, and density of fish observed with the primary goal of estimating juvenile summer steelhead production. In addition, information pertaining to the presence of salmonids and non-salmonids can be used to provide input for the Ecosystem Diagnosis and Treatment Model in the Predation Risk, Fish Community Richness, and Fish Species Introductions attribute fields.

Site Assessment - Weather Record the weather conditions (clear, overcast, rainy, etc.)


low flow period in late summer when water temperatures exceed 9C

Site Assessment - Visibility Measure the visual distance to determine the number of snorkelers needed to survey a given reach on a given day. Three rules are applied to do this: 1) if one snorkeler can observe the entire width of the stream then only one snorkel should conduct the survey. This will be the case for most small tributary streams. 2) On medium sized tributaries a snorkeler should take one end of a measuring tape and back away from the bank while another person holds the tape. Once the snorkeler can no longer clearly see detail along the bank. The person on shore will take a measurement of this distance. Then measure the wetted width of the stream and divide the wetted width by the visual distance to determine the number of snorkels. 3) The maximum number of snorkels will be five regardless of the size of the stream or river.

Site Assessment - Depth On larger streams with maximum depths greater than 3 meters the visual depth should be measured. A snorkeler will enter the deepest area of the stream and drop a small unpainted lead weight attached to a string toward the bottom until it can no longer be seen then slowly begin raising the weight, marking the string at the depth where it first becomes visible again. The string can be measured on shore to determine the depth.

Post-survey Visibility Score After snorkeling, the underwater visibility of each study reach is ranked on a scale of 0 to 3 where 0 = not snorkelable due to an extremely high amount of hiding cover or zero water visibility (No snorkel survey should be conducted, <25% visibility); 1 = high amount of hiding cover or poor water clarity (25%-50% visibility); 2 = moderate amount of hiding cover or moderate water clarity, neither of which were thought to impede accurate fish counts (50%-75% visibility); and 3 = little hiding cover and good water clarity (>75% visibility). If possible all snorkel surveys should be conducted when conditions are rated at a 2 or 3.

Equipment Dry suits or wet suits; Masks; Snorkels; Rubber soled boots; Hand held thermometer; Field forms/data logger; Wrist slates; Stopwatch; Submersible halogen light; Hand counters; Underwater white boards; Measuring rods


5

Survey Step-by-step

Step 1: After team members don their wetsuits, a quick equipment check will ensure that all members have the

necessary tools to complete their survey.

Step 2: Measure the visual distance to determine the number of snorkelers needed to survey a given reach on a given

day. Three rules are applied to do this: 1) if one snorkeler can observe the entire width of the stream then only one

snorkel should conduct the survey. This will be the case for most small tributary streams. 2) On medium sized tributaries

a snorkeler should take one end of a measuring tape and back away from the bank while another person holds the tape.

Once the snorkeler can no longer clearly see detail along the bank. The person on shore will take a measurement of this

distance. Then measure the wetted width of the stream and divide the wetted width by the visual distance to determine

the number of snorkels. 3) The maximum number of snorkels will be five regardless of the size of the stream or river. On

larger streams with maximum depths greater than 3 meters the visual depth should be measured. A snorkeler will enter

the deepest area of the stream and drop a small unpainted lead weight attached to a string toward the bottom until it

can no longer be seen then slowly begin raising the weight, marking the string at the depth where it first becomes visible

again. The string can be measured on shore to determine the depth.

Note: A minimum of two persons should be present during snorkel surveys. A two person snorkeling crews can conduct

snorkel surveys in many wadeable streams. In wadeable stream reaches, one crew member should snorkel each transect

and record their observations on a wrist slate. The second crew member locates transect flags and makes sure the

snorkeler knows when they reach the end of the transect. The second crew member also provides an added measure of

safety for the snorkeler.

Step 3: Before starting a survey, record the weather conditions and water temperature (clear, overcast, rainy, etc.). In all

wadeable and most non-wadeable stream reaches, snorkeling should involve only a single pass through areas that are

deep enough to survey. At the end of the entire reach again record weather conditions, temperature, and total time

required to snorkel the reach. Note: Team members need to look downstream periodically and read the water for areas

of increased flow or change of gradient (riffles, falls, or rapids). Before making a pass through an area of increased flow,

consider possible safety issues. Objects such as boulders and woody debris can pose a significant hazard, if team

members are not prepared. Studying the reach, before a survey, will alert team members to possible hazards so that

they can develop a plan for working through difficult areas.

Step 4: Wadeable Streams: Begin at the downstream boundary (Transect A) of the sample stream reach and proceed

upstream through the pools and riffles. All movements in the water need to be slow and careful to avoid creating a flight

response in fish observed (Thompson 2000) or reduce the visual distance by disturbing fine sediments. Members will

slowly proceed upstream with team members keeping each other in their line of sight. Where possible, members should

float, to avoid stirring up sediment with their feet or hands. If there are multiple groups within a reach, each group

should minimize disturbance so that visibility downstream is not compromised. Data should be recorded for each

transect by the snorkeler on a wrist slate. Non-wadeable Streams and Rivers: Begin at the upstream boundary (Transect

K). A team of five snorkelers will be used and work as three separate groups. Two snorkels will work in tandem to

observe fish along the right bank and other group of 2 will work the left bank. The bank teams will position one member

so that they can visually observe the bank and the other member will remain within an area approximately 2 times the

visual distance of the bank snorkeler or within visual distance of the secondary drop-off shelf. The fifth and final

snorkeler will roam the mid-channel area looking for the most like holding cover possible. Past surveys indicate that few

fish are observed in this area regardless of the number of snorkels used and most fish were observed in conjunction with

woody debris or mid channel bars. The fifth snorkeler should avoid being closer than 2-times the visual distance of any

other snorkeler. Snorkel survey on non-wadeable streams will occur in a downstream direction. Data should be recorded

for each transect by the snorkeler on a wrist slate.


6

Step 5: Counts of the number of fish should be recorded along entire transect area (A-B, B-C, etc.). When enumerating

and identifying fish observed, three levels of identification are possible. First, all fish encountered during the snorkel

survey should be identified to species, this is especially critical for salmonid species. Second, fish are identified as

unknown species of a known family. Lastly, every effort should be made to at least classify fish as a member of the

family salmonidea or unknown. Care should be taken to minimize the number of unidentified fish.

Step 6: In addition to enumerating all fish, salmonids should be lumped into the following length categories: 1) young of

the year (<100 mm), 2) juveniles (100-300mm), and 3) adults (>300mm).

Step 7: After snorkeling, the underwater visibility of each study reach is ranked on a scale of 0 to 3 where 0 = not

snorkelable due to an extremely high amount of hiding cover or zero water visibility (No snorkel survey should be

conducted, <25% visibility); 1 = high amount of hiding cover or poor water clarity (25%-50% visibility); 2 = moderate

amount of hiding cover or moderate water clarity, neither of which were thought to impede accurate fish counts (50%-

75% visibility); and 3 = little hiding cover and good water clarity (>75% visibility). If possible all snorkel surveys should be

conducted when conditions are rated at a 2 or 3.

Step 9: To calculate fish densities (fish/m2), determine the area for each reach by utilizing the physical habitat data

collected (previously described in Section 2 of the OBMEP Physical Habitat Protocols Field Manual). To calculate the

density of fish multiple the average width by reach length to get the area sampled. Then divide the total number of fish

along with the total number of all identified categories by the area sampled. Total count by species and for the family

salmonidea, and total O. mykiss should be developed along with the densities for juvenile O. mykiss and total fish

abundance should be calculated for the entire reach.

Step10: Consult Thurow (1994) for additional information.

Nez Perce Tribe - Snorkeling Methods

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MM.org ID 283

Monitoring Entity or Program Nez Perce Tribe

Method Name Snorkeling Methods

Method Owner Jacque Schei

Citation Author Nez Perce Tribe

Year 2010

Citation Title Metadata Description: Nez Perce Tribe Fisheries Research Data Collection Activities

Citation URL https://www.monitoringmethods.org/Method/DownloadDescription/283

Citation Publisher Nez Perce Tribe

Objective/Purpose/Metrics This protocol is designed to collect fish density (number/m2), biomass (grams/m2), fish size, and condition factor data per age group of juvenile anadromous salmonids. Snorkeling counts are the main sampling tool used, by habitat type, to determine density and relative abundance of juvenile Chinook salmon and steelhead of natural and hatchery origin as well as other co-existing species. Species of primary interest are spring, summer, and fall Chinook salmon and summer steelhead.

Site Assessment - Weather


Temperature is recorded prior to snorkeling. Water temperature must be at least 10 C before snorkeling commences.

Site Assessment - Visibility Visibility is recorded prior to snorkeling

Site Assessment - Depth

Post-survey Visibility Score

Equipment

Survey Step-by-step

Sampling for spring and summer Chinook salmon and summer steelhead will occur from June 1 to approximately

September 15 of each year. Snorkeling observations are conducted in areas of representative habitat types. Multiple

transects are surveyed. Snorkelers move slowly but steadily upstream in an assigned lane. The number of snorkelers is

dependent upon visibility and width of the stream. The snorkelers are not in a single line perpendicular to the stream.

Snorkelers are staggered forming a "V" shape. For example, if there are five snorkelers, one snorkeler will be close to

each bank and counting fish between themselves and the banks. The next two divers will be slightly downstream and

closer to the center of the stream. They count the fish that swim between themselves and the diver closest to the bank

on their side. The final diver is in the middle of the stream downstream of the other four at the point of the “V”-shape

and counts all the fish that swim between the previous two divers and him or herself. Chinook salmon are identified and

counted as sub-yearlings, yearlings, or adults. All steelhead and other species are identified and lengths are estimated to

the nearest inch. Observations are relayed to a data recorder walking behind the snorkelers. The recorder draws a map

of the reach noting major habitat types and easily recognizable features of the surrounding land. After snorkeling is

completed, total transect length and major habitat lengths and widths are measured. Visibility and temperature are

recorded prior to snorkeling. Water temperature must be at least 10 C before snorkeling commences.

ISEMP - Snorkeling

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MM.org ID 282

Monitoring Entity or Program ISEMP (Integrated Status and Effectiveness Monitoring Program)

Method Name Snorkeling

Method Owner Keely Murdoch

Citation Author Murdoch, K.

Year 2008

Citation Title A Field Manual of Scientific Protocols for Underwater Observations within the Upper Columbia Monitoring Strategy

Citation URL http://www.nwfsc.noaa.gov/research/divisions/cbd/mathbio/isemp/docs/isempsnorkelprotocols_final2008.pdf

Citation Publisher TerraAqua, Inc.

Objective/Purpose/Metrics This protocol is designed to collect fish abundance and species composition data so that, when used in conjunction with habitat data, fish densities can be estimated.

Site Assessment - Weather Describe the ambient light conditions during the snorkel event by characterizing cloud and light conditions as rainy, overcast, partially cloudy, or sunny.


Take water temperatures at the start and end of each snorkel. The bank tender (when applicable) or the crew leader will collect a temperature reading at the beginning and end of the snorkel survey using an alcohol based or digital (do not use a mercury thermometer) thermometer accurate to 1.0°C.

Site Assessment - Visibility Visibility should be measured at each site snorkeled using a 100 mm Rapala Model # XRD-10RT rainbow trout lure with hooks removed. The lure should be fastened to a string and placed in the mid-water column. A snorkeler should enter the water, move away from the lure perpendicular to the bank until the lure is not identifiable as a fish, then move back towards the lure until lure is visible. At this point the distance from the snorkeler to lure is measured in cm using a tape. This is repeated for a total of three snorkelers and distance recorded on the datasheet. For streams narrower than the maximum visibility, use the wetted width at transect A as the maximum visibility for that site.



Equipment Data Sheets; Tatum A clipboard; Wood Pencils; Thermometer Digital or alcohol-based thermometer accurate to 1°C; Collection permits; First Aid Kits; Glow Sticks for Night Surveys; Extra Ruler; Dry suit repair kit; Extra Batteries; Dive Light; Flagging; Permanent Marker; GPS and maps; Cell Phone, Satellite Phone, or Radio; Throw Bag; Duct Tape; Multi-purpose tool; Dry Suit or Wet Suit; Mask and Snorkel; Boots and Neoprene Socks; Gaiters; Neoprene Gloves/Dry Gloves; Neoprene hood; Data Cuff and Pencils; Ruler/or Dowel to aid in fish size estimation; Henderson Ice Mask Optional equipment for winter surveys; Knee Pads; Shin Pads Optional; Dive Lights; Ear plugs and ear drops; Food and Water

ISEMP - Snorkeling

9

Survey Step-by-step Step 1: The stream name and the complete site number (ex. WENMASTER-0222, or CBW05583-040619) should be clearly identified on each data sheet. Do not abbreviate site numbers on data sheets. Abbreviated site numbers can cause confusion as more data sets are added to the ISEMP program.

Step 2: If multiple data sheets are used at one site, write the stream name and site number on each sheet. Number each sheet “page ___ of ____” so that during data entry, or if hard copies needed at a later date, there will be no question whether or not the data set is complete.

Step 3: Enter the date the site was sampled, start time and stop time on every data sheet. Start and stop time should be recorded in “24-hour” or military time.

Step 4: Take water temperatures at the start and end of each snorkel. The bank tender (when applicable) or the crew leader will collect a temperature reading at the beginning and end of the snorkel survey using an alcohol based or digital (do not use a mercury thermometer) thermometer accurate to 1.0°C.

Step 5: Describe the ambient light conditions during the snorkel event by characterizing cloud and light conditions as rainy, overcast, partially cloudy, or sunny.

Step 6: Visibility should be measured at each site snorkeled using a 100 mm Rapala Model # XRD-10RT rainbow trout lure with hooks removed. The lure should be fastened to a string and placed in the mid-water column. A snorkeler should enter the water, move away from the lure perpendicular to the bank until the lure is not identifiable as a fish, and then move back towards the lure until lure is visible. At this point the distance from the snorkeler to lure is measured in cm using a tape. This is repeated for a total of three snorkelers and distance recorded on the datasheet. For streams narrower than the maximum visibility, use the wetted width at transect A as the maximum visibility for that site. To measure turbidity, a water sample is collected in 250 mm dark bottle at the location and time visibility is measured. Water samples for turbidity should be processed as soon as possible, but within a 12 hr period if samples are kept out of the sunlight and in a cool environment. Subsamples should be poured from the agitated 250 mm bottle into the 3 glass vials. Vials should be wiped clean with a Kem-wipe and wiped with a silicone lotion to prevent fogging on the bottle. Process each sample to the nearest 0.01 NTU using a turbidity meter and record measurements on the datasheet. The turbidity meter should be calibrated routinely as directed by manufacturer.

Step 7: Observers should enter the river approximately 5 meters downstream of the reach start and position themselves across the channel so that all fish can be seen. Bank tenders or the crew leader should make sure that observers are all ready and spread out evenly across the channel before beginning survey. Stream width, water clarity, and habitat complexity will determine the number of observers needed to complete the survey. Observers should not start counting fish until they have snorkeled past the flagging marking the start of the site.

Note: Night snorkeling will commence at the end of civil twilight for the official sunset for the town closest to the site (i.e., Enitat, Leavenworth, Wenatchee) from the U.S. Naval Observatory estimates or the observation of the first celestial body except the moon. The end of civil twilight for any particular location can be found at http://aa.usno.navy.mil/data/docs/RS_OneDay.html.

Step 8: Whenever possible snorkeling will proceed in an upstream direction. Looking upstream, observers should count fish that pass downstream to their left and coordinate with adjacent snorkelers to ensure that fish are not counted more than once, especially on adult fish. The far right bank snorkeler should count fish to both the left and right. If it is necessary to deviate from this design, the crew leader should ensure that all observers understand the change in the direction that fish are counted (i.e., counting fish that pass to the right instead of left). If bank tenders are used they should count fish in stream margins too shallow to snorkel. Fish should not be counted until the observer passes them. Counting fish ahead of the observer can result in inaccuracies and double counts. Fish should be identified and counted by species and size increments of 2 cm in odd numbers (e.g., 3, 5, 7…). Fish categorized as 1 cm will be from 0.1 cm to 2 cm, 3 cm size class will be from 2.1 cm to 4 cm, and so on. Unidentified species should be noted with estimated size. Write information on cuff or board. A list of species names, species codes, and commonly encountered size ranges are listed in Table 1. The commonly encountered size ranges are reported for salmonid juveniles only. While it is possible to observe a salmonid outside of these size ranges, the observer should closely scrutinize the fish to ensure that it is being

ISEMP - Snorkeling

10

properly identified. Sizes for adults can be highly variable. Identify trout and salmon to species; dace, suckers, whitefish, and sculpins should be identified to genus.

Table 1. Species, codes and common size range used in status/trend and effectiveness snorkel surveys in the Wenatchee and Entiat subbasins under the ISEMP. Species

Data Codes Common Sizes (cm)

Chinook Oncorhynchus tshawytscha CHIN 3 – 7

Chinook (hatchery residual) Oncorhynchus tshawytscha H-CHIN 17-30

Steelhead/RBT Oncorhynchus mykiss STHD 3-30

Hatchery Steelhead residuals1 Oncorhynchus mykiss H-STHD 20-30

Coho Oncorhynchus kisutch COHO 3-7

Coho (hatchery residual) Oncorhynchus kisutch H-COHO 17-30

Sockeye SOCK Unlikely to see juveniles, possible to see adults

Bull Trout Salvilinus confluentus BULL 5-60

Cutthroat Trout Oncorhynchus mykiss CUTT 3-30

Brook Trout Salvelinus fontinalis BROOK 3-30

Sculpin Cottus sp. SCULP 1-15

Dace Rhinichtys sp. Dace 5-13

Sucker Catostomas sp. SCKR 5-45

Whitefish WHTF 5-35

Red-Side Shiner Richardsonius balteatus RSS 5-13

Other: Catostomid and/or cyprinid fry less than 3 cm CC Fry 1, 3

Step 9: At status and trend sites observers will relay information to the bank tender at periodic intervals, or stop at break points to relay the data to the crew leader for recording onto an appropriate datasheet. Fish numbers are recorded by habitat unit during effectiveness monitoring surveys. Example data sheets are provided in Appendix A.

Step 10: The snorkel survey should stop at the end of the site, i.e., at A or K, and should not be carried beyond the site boundaries.

Step 11: When snorkeling a reach with multiple channels (such as braids, or side channels) communication with the habitat crew prior to the snorkeling event is essential. The observers should snorkel the same reach that was measured by the habitat crew. If multiple channels are included in the habitat data, then they should be snorkeled. If a side channel is excluded from the habitat data, it should not be snorkeled. However, if there is doubt about a side channel, side channels with more than 16% of the total flow should be snorkeled.

Step 12: In the event that water depth prohibits snorkeling upstream, the site may be snorkeled in a downstream manner following the same steps 1 - 11. Snorkelers must enter the water upstream of the site and float down with the current. When snorkeling downstream a pole (PVC pipe) is beneficial for keeping the crew in alignment (Thurow 1994).

Step 13: After the snorkel survey is complete the bank tenders or crew leaders should ensure that all flagging or glow sticks (night snorkeling) are removed from the site.

SRFB - Estimating Instream Juvenile Salmonid Abundance Using Snorkeling

11

MM.org ID 197

Monitoring Entity or Program SRFB (Washington Salmon Recovery Funding Board)

Method Name Estimating Instream Juvenile Salmonid Abundance Using Snorkeling


Citation Author Crawford, B.A.

Year 2011

Citation Title Method For Estimating Instream Juvenile Salmonid Abundance Using Snorkeling

Citation URL http://www.monitoringmethods.org/Method/DownloadDescription/197

Citation Publisher Washington Salmon Recovery Funding Board

Objective/Purpose/Metrics Estimating the density of juvenile salmonids at the project allows the investigator to obtain a sample over time of the change in abundance of rearing juvenile salmonids produced in the stream reach examined. Instead of a randomly selected stream reach, the stream reach impacted by the project is sampled. These “impact” reaches have been matched with “control” reaches of the same length and size on the same stream whenever possible in order to produce a BACI experimental design.



Measure the water temperature and record the temperature in the Juvenile Fish Survey Form.

Site Assessment - Visibility Estimate visibility as low, medium, or high and record it in the field form.

Site Assessment - Depth In many smaller streams the riffle areas will be too shallow to snorkel and will contain mostly smaller young of the year trout species.

Post-survey Visibility Score After snorkeling, the underwater visibility of each study reach is ranked on a scale of 0 to 3 where 0 = not snorkelable due to an extremely high amount of hiding cover or zero water visibility; 1 = high amount of hiding cover or poor water clarity; 2 = moderate amount of hiding cover or moderate water clarity, neither of which were thought to impede accurate fish counts; and 3 = little hiding cover and good water clarity.

Equipment Waterproof field forms or electronic forms are necessary for recording fish counts. A thermometer to measure water temperature is necessary. Persons conducting snorkel counts should be equipped with dry suits or wet suits, masks, snorkels, and rubber or felt soled boots. Additional equipment such as hand counters, underwater white boards, and dive lights are helpful for enumerating fish.

SRFB - Estimating Instream Juvenile Salmonid Abundance Using Snorkeling

12

Step-by-step Step 1: Measure the water temperature and record the temperature in the Juvenile Fish Survey Form. Estimate visibility as low, medium, or high and record it in the field form. Step 2: Begin at the downstream boundary of the control reach (Transect A) and proceed upstream through each Transect, ending at Transect K. In wadeable stream reaches, one crew member should snorkel each pool-riffle area while the other crew member records the counts as they are given by the snorkeler. In non-wadeable areas, crew members should snorkel side by side and sum their individual counts. Each snorkeler counts the fish to the immediate front and to the sides opposite the other snorkeler or as designated by the team leader to avoid duplication of counts. In all wadeable and most non-wadeable stream reaches, snorkeling should involve only a single pass through each Transect. Note: In many smaller streams the riffle areas will be too shallow to snorkel and will contain mostly smaller young of the year trout species. A two person snorkeling crew can conduct snorkel surveys in wadeable stream control and impact study reaches. In areas where the stream is not wadeable, up to four snorkelers may be needed. Step 3: Counts of the number of juvenile salmonids should be recorded from one Transect to the next (juvenile salmonids from Transect A to B, Transect B to C, etc.) in the Juvenile Fish Survey Form. Continue proceeding upstream counting the number of juvenile salmonids until the survey is completed at Transect K. Salmonid forklengths should be estimated to the nearest 5 mm. Step 4: After snorkeling, the underwater visibility of each study reach is ranked on a scale of 0 to 3 (see Table 4) and recorded on the Juvenile Fish Survey Form. Note: Only reaches with a visibility rank of two or three should be used in data analysis. Where possible, the proportion of trout estimated by sample electrofishing that were cutthroat and steelhead should be used to reclassify unknown trout as underwater determination of species is often impossible. Step 5: Proceed to the impact reach and repeat steps 1-4. Step 6: Determine the area (m2) for both the control and impact reaches by utilizing the data collected for each reach in Step 4 of the Method for Characterizing Stream Morphology, Thalweg Profile. Reach area is determined by multiplying the averaged wetted width by the reach length. Step 7: For each study reach, the number of fish/m2 can be calculated for each salmonid species by dividing the total number of fish counted for each species (Step 3) which are < 250 mm by the reach area. This would result in fish/m2 for each species in the control reach and in the impact reach. Note: Consult Thurow (1994) and Johnson et al. (2007) for additional information.

ISEMP – Snorkel Herding

13

MM.org ID 205

Monitoring Entity or Program ISEMP (Integrated Status and Effectiveness Monitoring Program)

Method Name Fish Capture-Snorkel Herding

Method Owner Carol Volk

Citation Author Tattam, I.

Year 2009

Citation Title Remote Location Fish Capture (2007-2009)

Citation URL http://www.nwfsc.noaa.gov/research/divisions/cbd/mathbio/isemp/docs/isemp_johnday_pit_protocol-final.pdf

Citation Publisher EcoLogical, Inc.

Objective/Purpose/Metrics This method is employed when capturing and PIT tagging juvenile salmonids at remote locations to estimate seasonal survival, growth rates, densities, abundance, and distribution as potential responses to habitat conditions



<8 C is preferred, sampling stops when temperatures exceed 18 C

Site Assessment - Visibility Water visibility > 0.25 m (based on a visual estimate)



Equipment Drysuit/wetsuit and mask/snorkel; Bag seine net (3.7 m wide and 1.2 m deep, with 6.4 mm mesh) strung on two 1.5 m poles; Additional 1-2 poles for anchoring middle of net; Buckets; Cup for transferring fish from net to buckets

Step-by-step As of 2008 all fish capture and tagging reaches are permanently marked and the same distances are sampled each year.

The start and stop locations are marked with rebar to aid relocation.

There should be a minimum crew of 3 with two people holding the net and one snorkeler. The addition of a fourth

person to transport the fish between sampling sites and transfer fish from the net provides greater efficiency as

compared to a crew of 3. In streams with pool widths > 6m, two divers may be advantageous in some instances. Thus, in

these situations, a crew of 4 would be the minimum with a crew of 5 being optimal.

A. 2 people should set the bag net in the thalweg (the axis of greatest depth and velocity), at the downstream edge of

lanes where fish are most likely to run for escape. Bag is positioned in most likely escape route. The net should be

carefully “edged” upstream into the pool, such that it is in sufficiently deep water that fish will be willing to enter the

net.

B. Diver(s) moves rapidly downstream from the riffle down into the pool where the net is set, and chases fish into bag

net while vigorously reaching into all areas of the unit (e.g., cutbanks, woody debris, or other structured habitat). This is

called a snerd pass.

C. Fish captured are generally held for later processing, although non‐target species may be immediately counted and

released.

D. The number of non‐target captures and the number of Snerd hauls conducted are tallied on the field form each time

capture efforts pause, and the fish are marked.

SRFB - Detecting Fish Species Assemblages Using Backpack Electrofishing or Snorkeling

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MM.org ID 165

Monitoring Entity or Program SRFB (Washington Salmon Recovery Funding Board)

Method Name Detecting Fish Species Assemblages Using Backpack Electrofishing or Snorkeling


Citation Author Crawford, B.A., & Arnett, J.

Year 2011

Citation Title Method for Detecting Fish Species Assemblages Using Backpack Electrofishing or Snorkeling

Citation URL http://www.monitoringmethods.org/Method/DownloadDescription/165

Citation Publisher Washington Salmon Recovery Funding Board

Objective/Purpose/Metrics This method is designed to calculate an Index of Biological Integrity (IBI) for fish species found within the sampled study reach. The health of a stream in terms of fish can be determined by species composition and age class structures. The IBI will be used to compare the changes, if any, in the fish population structure over time.



Measure the water temperature and record the temperature in the Juvenile Fish Survey Form.

Site Assessment - Visibility Estimate visibility as low, medium, or high and record it in the field form.

Site Assessment - Depth In many smaller streams the riffle areas will be too shallow to snorkel and will contain mostly smaller young of the year trout species.

Post-survey Visibility Score After snorkeling, the underwater visibility of each study reach is ranked on a scale of 0 to 3 where 0 = not snorkelable due to an extremely high amount of hiding cover or zero water visibility; 1 = high amount of hiding cover or poor water clarity; 2 = moderate amount of hiding cover or moderate water clarity, neither of which were thought to impede accurate fish counts; and 3 = little hiding cover and good water clarity.

Equipment Persons conducting snorkel counts should be equipped with dry suits or wet suits, masks, snorkels, and rubber soled boots. Additional equipment such as hand counters, dive lights, and underwater white boards are helpful for enumerating fish. A 30 X 30 PVC quadrat, fish identification book/chart(s), measuring device, clear box (at least 3 inches tall), camera, and two aquarium nets are needed for the demersal fish survey. Waterproof forms or electronic forms are necessary for recording all fish counts.

SRFB - Detecting Fish Species Assemblages Using Backpack Electrofishing or Snorkeling

15

Step-by-step SNORKELING SAMPLING PROCEDURES

Step 1: Measure the water temperature and record the temperature in the Juvenile Fish Survey Form. Estimate visibility

as low, medium, or high and record it in the field form. Begin at the downstream boundary of the control reach

(Transect A) and proceed upstream through each Transect, ending at Transect K. In many smaller streams the riffle areas

will be too shallow to snorkel and will contain mostly smaller young of the year trout species.

Step 2: A two person snorkeling crew can conduct snorkel surveys in wadeable stream control and impact study reaches.

In areas where the stream is not wadeable, up to four snorkelers may be needed. In wadeable stream reaches, one crew

member should snorkel each pool-riffle area while the other crew member records the counts as they are given by the

snorkeler. In non-wadeable areas, crew members should snorkel side by side and sum their individual counts. Each

snorkeler counts the fish to the immediate front and to the sides opposite the other snorkeler or as designated by the

team leader to avoid duplication of counts.

Step 3: In all wadeable and most non-wadeable stream reaches, snorkeling should involve only a single pass through

each Transect.

Step 4: All species of fish observed from one Transect to the next (A to B, B to C, etc.) should be enumerated, identified,

and recorded (Fish Survey Form, Figure 9). Forklengths should be estimated to the nearest 5 mm. Continue proceeding

upstream until the survey is completed at Transect K. Forklengths should be estimated to the nearest 5 mm.

Step 5: After snorkeling, the underwater visibility of each study reach is ranked on a scale of 0 to 3 where 0 = not

snorkelable due to an extremely high amount of hiding cover or zero water visibility; 1 = high amount of hiding cover or

poor water clarity; 2 = moderate amount of hiding cover or moderate water clarity, neither of which were thought to

impede accurate fish counts; and 3 = little hiding cover and good water clarity.

Step 6: Only reaches with a visibility rank of two or three should be used in data analysis. Where possible, the proportion

of trout estimated by sample snorkeling/electrofishing that was cutthroat and steelhead should be used to reclassify

unknown trout as underwater determination of species is often impossible.

Step 7: Determine the reach area (m2) by utilizing the data collected for each reach in Steps 1-6 of the Method for

Measuring Wetted Width. Reach area is determined by multiplying the averaged wetted width by the reach length.

Step 8: For each study reach, the number of fish/m2 can be calculated for each salmonid species by dividing the total

number of fish counted for each species (Step 4). This would result in fish/m2 for each species in the control reach and

in the impact reach.

Step 9: Consult Thurow (1994) and Johnson et al. (2007) for additional information.

General Guidance - Mark-Recapture Estimates from Snorkeling Data

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MM.org ID 137


Method Name Mark-Recapture Estimates from Snorkeling Data


Citation Author O'Neal, J.S.

Year 2007

Citation Title Mark-Recapture Estimates from Snorkeling Data

Citation URL http://www.stateofthesalmon.org/fieldprotocols/downloads/SFPH_p10.pdf

Citation Publisher American Fisheries Society

Objective/Purpose/Metrics Snorkel surveys can be used with other techniques to estimate abundance using mark–recapture techniques. The use of snorkel surveys for mark–recapture estimates provides a calibration factor for the counting efficiency of snorkel surveys as compared to other methods such as electrofishing and seining.

Site Assessment - Weather Weather conditions should be recorded on the datasheet


Temperature should be between 10°C and 18°C for daytime survey, and less than 10°C or greater than 18°C for night survey (1 h after sunset)

Site Assessment - Visibility The minimum recommended visibility for surveys is 1.5 m (P. Roni, NOAA Fisheries, personal communication). Visibility during typical summer base-flow periods is often much greater. Snorkelers can evaluate clarity by using a silhouette of a salmonid with parr marks and spots, as described in Thurow (1994). A surveyor should approach the silhouette until the parr marks are clearly visible and then move away from the silhouette until the marks cannot be distinguished. The average of these two distances provides the water visibility (Thurow 1994).

Site Assessment - Depth Minimum recommended water depth for successful surveys is 20 cm

Post-survey Visibility Score Rodgers (2002) recommends ranking turbidity at each reach surveyed. Data can then be segregated for precision based on visibility. Rank underwater visibility of each pool on a scale of 0 to 3 where: 0 = not snorkelable due to an extremely high amount of hiding cover or zero water visibility; 1 = high amount of hiding cover or poor water clarity; 2 = moderate amount of hiding cover or moderate water clarity neither of which were thought to impede accurate fish counts; and 3 = little hiding cover and good water clarity.

Equipment In addition to equipment listed in General Guidance – Basic Snorkel Survey Procedures you will need block nets, and equipment for collecting and marking fish (electrofishing, seining, or trapping; marking is done using tags or dyes with color coding or patterns).

Step-by-step For this technique to be used, the system should be closed off with block nets so that the total population observed is

constant. For mark–recapture estimates, fish need to be collected, marked, and released back to the sample area.

Collection occurs with electrofishing, seining, or trapping; marking is done using tags or dyes with color coding or

patterns; and release is into the sample reach. Snorkel surveys can then be conducted in the same sample reach to

count the number of marked fish. The ratio of the number of fish resighted (i.e., those with marks that are counted) can

be used as a calibration factor for the effectiveness of a snorkel survey compared to other survey methods. Fish can be

marked differently based on size-class and species recorded by observers, which can help identify those species and

size-classes that may have been undercounted using a snorkel survey approach.

General Guidance - Estimating Fish Total Length Underwater

17

MM.org ID 1747


Method Name Estimating Fish Total Length Underwater

Method Owner PNAMP Support

Citation Author Thurow, R.F.

Year 1994

Citation Title Underwater Methods for Study of Salmonids in the Intermountain West

Citation URL http://www.fs.fed.us/rm/pubs_int/int_gtr307.pdf

Citation Publisher USDA Forest Service

Objective/Purpose/Metrics To determine fish lengths (for adults and juveniles) during underwater activities when it is not feasible to use a measuring board.

Equipment snorkel mask, rulers, counting sleeve

Step-by-step

1. To estimate total length, approach the fish underwater

2. Align the tip of the snout and the longest caudal ray fin with adjacent objects and measure that distance with a ruler,

in mm or cm (Cunjak and Power 1986). Snorkelers can carry a ruler, mark one on their counting sleeve, or use a known

distance (index finger to thumb, for example). Snorkelers should continually check their size estimates throughout the

field season.

3. Typically, individual total lengths are not recorded, but are tallied into size classes by species. The timing of

emergence and growth rates vary among watersheds, and observers need to adjust their size classes accordingly. This is

particularly true for estimating age classes of steelhead and other trout. Below are some example size classes:

Steelhead: Three distinct size classes are usually present: age 1 (70 to 130 mm), age 2 (130 to 200 mm), and age 3 (200

to 250 mm) (Everest 1969; Thurow 1985).

Chinook: Juvenile Chinook will be of two discrete size classes: age 0 (50 to 80 mm) and age 1 (longer than 100 mm).

Snorkelers can practice estimating fish sizes by viewing objects and fish of known sizes underwater. Calibrated wooden

dowels or floating cutouts of fish of various sizes can be attached to weights and distributed throughout a stream

channel. Snorkelers approach each object and estimate its size. Live fish of known size can also be used. One method is

to individually mark fish of known sizes in a stream reach. Snorkelers approach each marked fish and estimate its size.

Another method is to capture fish of several size classes and place them in temporary live cages (Rich 1993). Snorkelers

independently view each fish and report their results to an instructor.

Comparison Tables

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Abbr. ID Monitoring Entity or Program Method Name

BSG 136 General Guidance Basic Snorkel Survey Procedures

CCT 98 The Colville Confederated Tribes Snorkel Survey Methodology

NPT 283 Nez Perce Tribe Snorkeling Methods

ISEMP 282 ISEMP Snorkeling

Abun 197 Washington Salmon Recovery Funding Board Estimating Instream Juvenile Salmonid Abundance Using Snorkeling

Snerd 205 ISEMP Fish Capture-Snorkel Herding

Asmblg 165 Washington Salmon Recovery Funding Board Detecting Fish Species Assemblages Using Backpack Electrofishing or Snorkeling

M-R 137 General Guidance Mark-Recapture Estimates from Snorkeling Data

Objective/Purpose/Metrics

BSG Relative and total abundance, fish distribution, presence/absence surveys, species assemblages (i.e., diversity), some stock characteristics (e.g., length estimation), and habitat use, information on individual or group movement, behavior, and habitat associations. Snorkel surveys can be combined with other methods such as sonar and tools such as geographic information systems (GIS) to generate three-dimensional maps of habitat use by fish species. Calculating population estimates can be done with mark-re-sight techniques.

CCT Estimating the abundance, species, and density of fish observed with the primary goal of estimating juvenile summer steelhead production. In addition, information pertaining to the presence of salmonids and non-salmonids can be used to provide input for the Ecosystem Diagnosis and Treatment Model in the Predation Risk, Fish Community Richness, and Fish Species Introductions attribute fields.

NPT This protocol is designed to collect fish density (number/m2), biomass (grams/m2), fish size, and condition factor data per age group of juvenile anadromous salmonids. Snorkeling counts are the main sampling tool used, by habitat type, to determine density and relative abundance of juvenile Chinook salmon and steelhead of natural and hatchery origin as well as other co-existing species. Species of primary interest are spring, summer, and fall Chinook salmon and summer steelhead.

ISEMP This protocol is designed to collect fish abundance and species composition data so that, when used in conjunction with habitat data, fish densities can be estimated.

Abun Estimating the density of juvenile salmonids at the project allows the investigator to obtain a sample over time of the change in abundance of rearing juvenile salmonids produced in the stream reach examined. Instead of a randomly selected stream reach, the stream reach impacted by the project is sampled. These “impact” reaches have been matched with “control” reaches of the same length and size on the same stream whenever possible in order to produce a BACI experimental design.

Snerd This method is employed when capturing and PIT tagging juvenile salmonids at remote locations to estimate seasonal survival, growth rates, densities, abundance, and distribution as potential responses to habitat conditions

Asmblg This method is designed to calculate an Index of Biological Integrity (IBI) for fish species found within the sampled study reach. The health of a stream in terms of fish can be determined by species composition and age class structures. The IBI will be used to compare the changes, if any, in the fish population structure over time.

M-R Snorkel surveys can be used with other techniques to estimate abundance using mark–recapture techniques. The use of snorkel surveys for mark–recapture estimates provides a calibration factor for the counting efficiency of snorkel surveys as compared to other methods such as electrofishing and seining.

19


BSG Weather conditions should be recorded on the datasheet

CCT Record the weather conditions (clear, overcast, rainy, etc.)

NPT

ISEMP Describe the ambient light conditions during the snorkel event by characterizing cloud and light conditions as rainy, overcast, partially cloudy, or sunny.

Abun

Snerd

Asmblg

M-R Weather conditions should be recorded on the datasheet


BSG Temperature should be between 10°C and 18°C for daytime survey, and less than 10°C or greater than 18°C for night survey (1 h after sunset)

CCT low flow period in late summer when water temperatures exceed 9C

NPT Temperature is recorded prior to snorkeling. Water temperature must be at least 10 C before snorkeling commences.

ISEMP Take water temperatures at the start and end of each snorkel. The bank tender (when applicable) or the crew leader will collect a temperature reading at the beginning and end of the snorkel survey using an alcohol based or digital (do not use a mercury thermometer) thermometer accurate to 1.0°C.

Abun Measure the water temperature and record the temperature in the Juvenile Fish Survey Form.

Snerd <8 C is preferred, sampling stops when temperatures exceed 18 C

Asmblg Measure the water temperature and record the temperature in the Juvenile Fish Survey Form.

M-R Temperature should be between 10°C and 18°C for daytime survey, and less than 10°C or greater than 18°C for night survey (1 h after sunset)


BSG Minimum recommended water depth for successful surveys is 20 cm

CCT On larger streams with maximum depths greater than 3 meters the visual depth should be measured. A snorkeler will enter the deepest area of the stream and drop a small unpainted lead weight attached to a string toward the bottom until it can no longer be seen then slowly begin raising the weight, marking the string at the depth where it first becomes visible again. The string can be measured on shore to determine the depth.

NPT

ISEMP

Abun In many smaller streams the riffle areas will be too shallow to snorkel and will contain mostly smaller young of the year trout species.

Snerd

Asmblg In many smaller streams the riffle areas will be too shallow to snorkel and will contain mostly smaller young of the year trout species.

M-R Minimum recommended water depth for successful surveys is 20 cm

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Site Assessment - Visibility

BSG The minimum recommended visibility for surveys is 1.5 m (P. Roni, NOAA Fisheries, personal communication). Visibility during typical summer base-flow periods is often much greater. Snorkelers can evaluate clarity by using a silhouette of a salmonid with parr marks and spots, as described in Thurow (1994). A surveyor should approach the silhouette until the parr marks are clearly visible and then move away from the silhouette until the marks cannot be distinguished. The average of these two distances provides the water visibility (Thurow 1994).

CCT Measure the visual distance to determine the number of snorkelers needed to survey a given reach on a given day. Three rules are applied to do this: 1) if one snorkeler can observe the entire width of the stream then only one snorkel should conduct the survey. This will be the case for most small tributary streams. 2) On medium sized tributaries a snorkeler should take one end of a measuring tape and back away from the bank while another person holds the tape. Once the snorkeler can no longer clearly see detail along the bank. The person on shore will take a measurement of this distance. Then measure the wetted width of the stream and divide the wetted width by the visual distance to determine the number of snorkels. 3) The maximum number of snorkels will be five regardless of the size of the stream or river.

NPT Visibility is recorded prior to snorkeling

ISEMP Visibility should be measured at each site snorkeled using a 100 mm Rapala Model # XRD-10RT rainbow trout lure with hooks removed. The lure should be fastened to a string and placed in the mid-water column. A snorkeler should enter the water, move away from the lure perpendicular to the bank until the lure is not identifiable as a fish, and then move back towards the lure until lure is visible. At this point the distance from the snorkeler to lure is measured in cm using a tape. This is repeated for a total of three snorkelers and distance recorded on the datasheet. For streams narrower than the maximum visibility, use the wetted width at transect A as the maximum visibility for that site.

Abun Estimate visibility as low, medium, or high and record it in the field form.

Snerd Water visibility > 0.25 m (based on a visual estimate)

Asmblg Estimate visibility as low, medium, or high and record it in the field form.

M-R The minimum recommended visibility for surveys is 1.5 m (P. Roni, NOAA Fisheries, personal communication). Visibility during typical summer base-flow periods is often much greater. Snorkelers can evaluate clarity by using a silhouette of a salmonid with parr marks and spots, as described in Thurow (1994). A surveyor should approach the silhouette until the parr marks are clearly visible and then move away from the silhouette until the marks cannot be distinguished. The average of these two distances provides the water visibility (Thurow 1994).


BSG Rodgers (2002) recommends ranking turbidity at each reach surveyed. Data can then be segregated for precision based on visibility. Rank underwater visibility of each pool on a scale of 0 to 3 where: 0 = not snorkelable due to an extremely high amount of hiding cover or zero water visibility; 1 = high amount of hiding cover or poor water clarity; 2 = moderate amount of hiding cover or moderate water clarity neither of which were thought to impede accurate fish counts; and 3 = little hiding cover and good water clarity.

CCT After snorkeling, the underwater visibility of each study reach is ranked on a scale of 0 to 3 where 0 = not snorkelable due to an extremely high amount of hiding cover or zero water visibility (No snorkel survey should be conducted, <25% visibility); 1 = high amount of hiding cover or poor water clarity (25%-50% visibility); 2 = moderate amount of hiding cover or moderate water clarity, neither of which were thought to impede accurate fish counts (50%-75% visibility); and 3 = little hiding cover and good water clarity (>75% visibility). If possible all snorkel surveys should be conducted when conditions are rated at a 2 or 3.

NPT

ISEMP

Abun After snorkeling, the underwater visibility of each study reach is ranked on a scale of 0 to 3 where 0 = not snorkelable due to an extremely high amount of hiding cover or zero water visibility; 1 = high amount of hiding cover or poor water clarity; 2 = moderate amount of hiding cover or moderate water clarity, neither

21

of which were thought to impede accurate fish counts; and 3 = little hiding cover and good water clarity.

Snerd

Asmblg After snorkeling, the underwater visibility of each study reach is ranked on a scale of 0 to 3 where 0 = not snorkelable due to an extremely high amount of hiding cover or zero water visibility; 1 = high amount of hiding cover or poor water clarity; 2 = moderate amount of hiding cover or moderate water clarity, neither of which were thought to impede accurate fish counts; and 3 = little hiding cover and good water clarity.

M-R Rodgers (2002) recommends ranking turbidity at each reach surveyed. Data can then be segregated for precision based on visibility. Rank underwater visibility of each pool on a scale of 0 to 3 where: 0 = not snorkelable due to an extremely high amount of hiding cover or zero water visibility; 1 = high amount of hiding cover or poor water clarity; 2 = moderate amount of hiding cover or moderate water clarity neither of which were thought to impede accurate fish counts; and 3 = little hiding cover and good water clarity.

Equipment

BSG For daytime surveys (water temperature greater than 9°C): Full neoprene wet suit (6.4 mm) or dry suit with knee pads, preferably black or blue or brown; Wet suit hood; Neoprene gloves; Neoprene socks; Wading boots with felt soles; Fins (can be useful in large systems when surveys must be conducted downstream); Mask with side window to increase visibility; Snorkel; Extra mask and snorkel for remote reaches; Data recorders such as a dive slate scroll (Ogden 1977) or a plastic cuff (10-cm PVC pipe in 20-cm lengths will work and can be secured with surgical tubing [Helfman 1983]); Grease pencil; Knee and elbow pads (for turbulent or shallow streams); Wet suit cement or Aquaseal® for repairing suits; Thermometer; Small halogen light; Canteen; Food; First-aid kit; Mobile phone and/or radio for emergency contact; Data forms; Measuring tape; Flagging. For nighttime surveys or daytime surveys where water temperature is less than 10°C: Everything listed above and the following: Dry suit (required) (should not have valves if possible); Adequate insulation under dry suit; Handheld halogen dive lights (a red filter can be helpful for reducing fish disturbance; filters can be made from red Plexiglas)

CCT Dry suits or wet suits; Masks; Snorkels; Rubber soled boots; Hand held thermometer; Field forms/data logger; Wrist slates; Stopwatch; Submersible halogen light; Hand counters; Underwater white boards; Measuring rods

NPT

ISEMP Data Sheets; Tatum A clipboard; Wood Pencils; Thermometer Digital or alcohol-based thermometer accurate to 1°C; Collection permits; First Aid Kits; Glow Sticks for Night Surveys; Extra Ruler; Dry suit repair kit; Extra Batteries; Dive Light; Flagging; Permanent Marker; GPS and maps; Cell Phone, Satellite Phone, or Radio; Throw Bag; Duct Tape; Multi-purpose tool; Dry Suit or Wet Suit; Mask and Snorkel; Boots and Neoprene Socks; Gaiters; Neoprene Gloves/Dry Gloves; Neoprene hood; Data Cuff and Pencils; Ruler/or Dowel to aid in fish size estimation; Henderson Ice Mask Optional equipment for winter surveys; Knee Pads; Shin Pads Optional; Dive Lights; Ear plugs and ear drops; Food and Water

Abun Waterproof field forms or electronic forms are necessary for recording fish counts. A thermometer to measure water temperature is necessary. Persons conducting snorkel counts should be equipped with dry suits or wet suits, masks, snorkels, and rubber or felt soled boots. Additional equipment such as hand counters, underwater white boards, and dive lights are helpful for enumerating fish.

Snerd Drysuit/wetsuit and mask/snorkel; Bag seine net (3.7 m wide and 1.2 m deep, with 6.4 mm mesh) strung on two 1.5 m poles; Additional 1-2 poles for anchoring middle of net; Buckets; Cup for transferring fish from net to buckets

Asmblg Persons conducting snorkel counts should be equipped with dry suits or wet suits, masks, snorkels, and rubber soled boots. Additional equipment such as hand counters, dive lights, and underwater white boards are helpful for enumerating fish. A 30 X 30 PVC quadrat, fish identification book/chart(s), measuring device, clear box (at least 3 inches tall), camera, and two aquarium nets are needed for the demersal fish survey. Waterproof forms or electronic forms are necessary for recording all fish counts.

M-R In addition to equipment listed in General Guidance – Basic Snorkel Survey Procedures you will need block nets, and equipment for collecting and marking fish (electrofishing, seining, or trapping; marking is done using tags or dyes with color coding or patterns).

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Survey Approach Potential Objectives

Snorkel survey

• Observation of species/Distribution

• Presence/Absence/Behavior/Structure Use

• Count by species/size/Diversity

• Local abundance estimate

• Juvenile/adult density

• Age class distribution

Snerding (Snorkel Herding) • Employed with PIT Tagging for survival and growth rates

• Estimate density, abundance, distribution as responses to habitat condition

Snorkeling with electrofishing calibration

• More precise estimates of abundance, density, age class distribution, etc.

Snorkeling as part of mark/re-sight survey

• Population estimates/Growth Rates/Production

• Localized abundance

snorkeling methods - pnamp · post-survey visibility score rodgers ... grease pencil; knee and...

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