COOK INLET AQUACULTURE ASSOCIATION Kalifornsky Beach Road Kenai, Alaska Phone: (907)

Transcription

1 SESSION I SMOLT ENUMERATION PROCEDURES MANUAL Prepared by: CIAA Staff Members Revised March 12, 2007 COOK INLET AQUACULTURE ASSOCIATION Kalifornsky Beach Road Kenai, Alaska Phone: (907)

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3 TABLE OF CONTENTS INTRODUCTION...1 SMOLT MIGRATION...2 COLLECTION FACILITY...2 SMOLT DESCRIPTION...5 SMOLT ENUMERATION...8 THE TOTAL COUNT PROCEDURE...8 THE TEN PERCENT SUB-SAMPLING PROCEDURE...10 DATA SHEET COMPLETION PROCEDURE...19 ENVIRONMENT DAILY LOG...20 SMOLT DAILY LOG...20 SMOLT AWL DATA SHEET...21 i

4 Table of Figures FIGURE 1: SCHEMATIC DIAGRAM OF THE SMOLT TRAP...3 FIGURE 2: THE SMOLT COLLECTION FACILITY...4 FIGURE 3. SOCKEYE SALMON SMOLT...5 FIGURE 4. COHO SALMON SMOLT...6 FIGURE 5. COHO SALMON SMOLT/SOCKEYE SALMON SMOLT COMPARISION..7 FIGURE 6: TEN PERCENT SUB-SAMPLING WOOKSHEET...14 FIGURE 7: SMOLT AWL PROCEDURE...18 FIGURE 8: ENVIRONMENT DAILY LOG...22 FIGURE 9: SMOLT DAILY LOG...23 FIGURE 10: SMOLT AWL DATA SHEET...24 ii

5 INTRODUCTION This manual is a training and reference guide describing the field data gathering techniques used by Cook Inlet Aquaculture Association (CIAA) for assessing salmon populations. These techniques are used in streams where it is possible to trap and count all downstream and upstream migrating fish. The goal of this manual is to promote consistent sampling procedures year to year, regardless of changes in personnel, weather or stream discharge. Consistent and accurate data collection on juvenile and adult life phases of salmon is required to evaluate the effectiveness of enhancement activities. This manual explains procedures used to enumerate salmon smolts emigrating from lake systems. Smolt refers to a stage in the development of juvenile salmon when they migrate seaward and undergo a series of morphological, physiological and behavioral transitions that include increased silvery coloration and salinity tolerance, Na'/K' ATPase activity in gills and downstream migratory activity. Smolt migrations for sockeye and coho salmon generally occur in May and June after the fish have spent one to three years in fresh water. Water temperature plays an important role in triggering the migration; with the exodus peaking soon after ice out as rearing lakes begin to warm. Your duty at the field camp will be to monitor the smolt migration. When the smolts are migrating at peak numbers you will most likely be very busy. However, you will have periods of time when the fish are not migrating heavily and you will be afforded a rest. It is important to 1

6 remember the peak of the migrations only constitutes a portion of the field season. Each day, call the CIAA office with the daily data and any needs or questions you may have. CIAA staff will make every attempt to provide you with the information and support you will need. SMOLT MIGRATION This section explains procedures used to enumerate smolt migrating from lake systems. First, the collection facility is described, then the key characters used to identify smolts by species are listed, and finally, the procedures used for counting migrating smolt are presented. In the field, you will observe mostly sockeye and coho smolts. Sockeye will dominate the migration, especially during the period following ice out. Collection Facility The collection facility in the field is composed of a modified fyke net and a two compartment live box. The fyke net has two leads which are anchored upstream to each bank and function by directing fish into the trap. The leads narrow to the fyke net which then narrows to a four foot by four foot entrance and then down to a two foot diameter cod end. The cod end is attached to the two compartment live box. The live box has a manually controlled gate which enables you to switch the compartment the smolts are directed into during ten percent sub-sampling. 2

7 Figure 1: Schematic diagram of the Smolt Trap It is important that the trap is inspected and maintained regularly to be "escape proof during operation. Tears in the fyke net should be repaired and the leads should not allow fish to swim under or around them. The leads, fyke net, and live box should be cleaned frequently to ensure ample water flow through the trap. The frequency with which the trap must be cleaned depends upon flow regimes and surface currents on the lake. You should be aware of debris loading and clean the traps as required. A brush will be provided with which you can remove debris from the fyke net and live box. 3

8 Figure 2: The smolt collection facility at Fish Creek 4

9 Smolt Description During the smolt migration there will be two or more species of salmon present and the trap will likely contain more than one species. It is important that the smolts being enumerated and sampled are properly identified. Key characteristics and accompanying illustrations of sockeye and coho smolt are shown below. Characteristics of Sockeye Smolt: 1) silvery color, 2) transparent fins, 3) slender body, 4) vague parr marks above the lateral line, 5) many gill rakers, and 6) few spots. Figure 3. Sockeye Salmon Smolt Characteristics of Coho Smolt: 1) Green/gold colored appearance, 2) blunt head, 3) robust shape, 4) several spots on the tail, 5) long visible parr marks that intersect the lateral line, 6) few, stout gill rakers, 7) pigmented fins, 8) anal fin is sickle-shaped, leading edge is longer than base, 9) 5

10 leading edges of anal and dorsal fins have white followed by black, 10) Adipose fin has dark edge, ceter is opaque, and 11) often caudal, anal and adipose fins are pale orange. Figure 4. Coho Salmon Smolt 6

11 Below, note the comparison of Sockeye and Coho body shape. Sockeye have a fusiform shape and coho are robust with a blunt head. Also note obvious spotting on the dorsal side of the coho. Coho Sockeye Figure 5. Coho Salmon Smolt/Sockeye Salmon Smolt Comparision 7

12 Smolt Enumeration The number of smolts migrating will vary as the season progresses. Initially you will encounter small numbers while water temperatures are cool and ice remains on the lake. Smolt numbers will peak around ice out and then gradually taper off. An increase in water temperature following ice out may signal an increase in smolt numbers. The majority of smolts will migrate at night, under cover of darkness, to avoid predation. Therefore, you will be required to work at night between 5 PM and 5AM. Some smolts will migrate during the day (5AM to 5 PM). Initially, the collection facility should be checked four times between 5 PM and 5 AM. All smolts are identified to species and a total count made. As the number of migrating smolts increase, these total counts are made every hour to avoidsmolt mortality in the collection facility. Smolts entering the collection facility during the day (5 AM to 5 PM) should be counted at least once, and sometimes more, depending on their numbers. During the peak migration, total counts may exceed 1,000 to 2,000 smolts per hour. At this time you must begin sub-sampling to avoid mortalities resulting from overcrowding of smolts in the live box. Sub-sampling provides only an estimate of smolt numbers during a given time period. Total counts are preferred over sub-sampling. Procedures for both total counts and sub-sampling are presented below. The Total Count Procedure Total counts are preferred over sub-sampling because sub-sampling provides only a estimate for a given time period. However, there will be periods during smolt migration when it will be impossible to conduct total counts due to the large number of migrating smolt. When smolt 8

13 numbers exceed 1,000 to 2,000 fish per hour you will have to sub-sample (see sub-sampling section). Initially total smolt counts are completed at least four times throughout the night (5 PM to 5 AM). As the number of migrating smolts increases, total counts must be mad every hour to avoid overcrowding in the live box. It is important that you monitor the smolts closely to observe for signs of stress and prevent mortalities due to overcrowding, During the day (5 AM to 5 PM), a total count of smolts is usually conducted once in the evening. The live box, however, still needs to be monitored periodically throughout the day. When the smolt migration is peaking, more than one day time total count may necessary to avoid overcrowding. At times, you may have to switch to the sub-sampling procedure. Generally, you will sleep from 6 AM to 1 PM. If large concentrations of smolts are entering the live box at 5 AM, continue to count smolts until their numbers diminish. When you leave the trap for the day, be certain that large numbers of smolt are not going to accumulate in the live box before leaving the trap. Smolts are counted by dip netting them out of the live box. Scoop up a small number of smolts into the dip net (approximately 4-5 smolt) and slowly pour them out of the dip net, identifying them by species and counting them. Gently drop them into the creek downstream of the trap as you pour them out of the net. It is very important to count the smolts as quickly as possible to avoid stressing the smolt or inducing mortality. Another method found useful when sockeye and coho are migrating together in large quantities is to transfer a few smolts at a time from the live 9

14 box to a small bucket or other container. Then slowly pour the smolts, one by one, out of the container counting and identifying each smolt to species. A headlamp and a white container make this procedure more efficient. You may desire to count smolts individually or as a team. When counting individually, each person has a dip net and tally counter and counts his or her own smolts. Use the tally counter to count sockeye smolts and keep a mental count of the coho. Once the net is emptied, add your mental count of coho to a separate tally counter reserved just for recording the number of coho. When counting as a team, one person operates the dip net and the other person identifies and counts the smolts using two tally counters, one for sockeye and one for coho. No matter which counting system is used, it is very important that you write down the numbers on your tally counters after every live box count and begin the next count with the tally counters set at zero. The tally counters can loose or gain numbers through bumping or dropping. Every time you count smolts, record the number of smolts and time of day when the count was completed. A weatherproof notebook will be provided to take with you to the trap, do not take this manual or the data sheets to the trap with you. Transfer the data from the weatherproof notebook to the data sheets at the tent (see section on Data Sheet Completion Procedures). The Ten Percent Sub-sampling Procedure During the peak of the smolt migration it may be impossible to count all the smolts that enter the live box without overcrowding and stressing the fish. This will occur when smolt numbers exceed 1,000 to 2,000 fish per hour. When this happens you must switch to the ten percent subsampling procedure. The theory behind this procedure is to sub-sample ten percent of the 10

15 smolts by counting two minutes out of every twenty. To help you understand the ten percent subsampling procedure a summary of the procedure is presented first, followed by an example to "walk" you through the procedure step by step. For sub-sampling to work properly, always have one side of the trap cleared of fish. Subsampling is done by opening and closing the trap gate, which directs smolt to the right or the left side of the two compartment live box. When sub-sampling, the downstream door on one side of the live box is opened to allow smolts to pass through the trap and continue downstream. The other compartment of the live box is where smolts are directed during the two minute subsampling period. The downstream door of this side of the live box must be closed to prevent smolts from continuing downstream. The ten percent sub-sampling work sheet (Figure 6) has predetermined, randomly selected times for the two minute sub-sampling time period to begin. Determine from the worksheet the two minute period you will sub-sample. Using the stopwatch, begin the two minute sub-sample by switching the gate and directing the smolt into the side of the live box that has the downstream door closed. Collect all smolts during this period. After the two minute time period has elapsed, close the gate on the sub-sampling compartment and allow smolts to pass through the other side of the live box, which has the downstream door open. Now count the smolts in the sub-sample compartment and multiply that number by ten. That expanded number is the estimated number of migrating smolt during that specific twenty minute period. This estimate is the number that is recorded on the works sheets. The following example will help to illustrate the ten percent sub- sampling procedure: 11

16 You have been conducting total counts every hour with both doors on the downstream end of the live box closed. You are sampling out of the left side of the trap and the right side is closed off with the manually controlled gate. You are checking and emptying the trap hourly. Without warning the number of migrating smolts increases rapidly and the left side of the live box soon has reached its capacity. The fish are stressed and mortalities could result from overcrowding. Do the following: 1) Open the downstream door on the side that does not contain smolt (in this example, the right side). 2) Note the time of day or night. Ten percent sub-sampling must begin at the top of the hour, twenty minutes after the hour, or forty minutes after the hour. At the beginning of the twenty minute period, open the trap gate to allow smolts to pass through the side of the trap that did not contain fish, which in this case is the right side. 3) While smolts are passing through the right side of the trap, continue to remove and count fish from the left side of the trap. The objective now is to clear all smolt out of the left side of the trap quickly so that you can begin sub-sampling at the predetermined two minute sub-sampling time. 4) When the left side of the trap is cleared of smolts and it is time to begin the two minute sub-sample, position the gate so that smolts are directed into the other side of the trap, in this example this would be the left side. Remember, the downstream door on this side of the trap is closed and the right side downstream door remains open. 12

17 When the two minutes have elapsed on the stopwatch, position the gate so that smolt are directed into the right side of the trap and are allowed to pass through the trap and continue downstream for the remainder of that twenty minute period. All smolts captured are then counted and released. That number is then multiplied by ten to estimate the total number for that twenty minute period. 5) Repeat the sub-sampling procedure, sampling two minutes out of every twenty, until the smolt numbers drop below 1,000 to 2,000 per hour. When smolt numbers have dropped to 1,000 to 2,000 per hour and you decide to switch from sub-sampling to total counts, it is very important that you continue to let smolt pass through the trap for the remaining time in the twenty minute time period after the last two minute subsample. After the remaining time in the twenty minute time period has elapsed, close off both downstream doors in the live box. Note the time you began the total counts and continue the enumeration following the total count procedure. 13

18 TEN PERCENT SUB-SAMPLE SMOLT ENUMERATION WORKSHEET Location: Project Date: Day / Night (Circle One) Sample Time Sockeye Coho Dollies Rainbow Other 1 5:16 2 5:27 3 5:49 4 6:03 5 6:33 6 6:56 Begin 10% Sub-sample at 7:00 pm 7 7: : : : : : : : : : : : : : : :19 Resume Total Counts at 12:00 am :31 57,980 17, : : : : : : : : : : : : :56 Totals Figure 6: Ten Percent Sub-sampling Worksheet 14

19 Smolts collected for evaluation are measured for weight and length, and scale samples are collected for age determination. To assess the Hatchery stocking program CIAA has marked all sockeye fry released into Big Lake, Hidden Lake and Bear Lake with an otolith (ear bone) band. To evaluate these programs, one additional procedural step is necessary; migrating smolt are collected and the otoliths are removed for analysis. Smolts collected for evaluation are collected in proportion to the daily migration. This is accomplished by collecting every n th fish that is counted. The number sequence begins when the first smolt is passed through the trap and continues consecutively until the smolt migration is complete. The intent of collecting weight and length (AWL) measurements and otoliths and scales from every n th fish is to determine the age, size and origin (enhanced vs. wild) of fish in the migration (See appendix for n = and x =). All project sites in the Susitna River system are wild, thus collection of otoliths is unnecessary. Procedures for collecting sockeye smolt, measuring them for weight and length, removing scales for age determination and extracting the otoliths are presented below: 1 1) As smolt are counted during the migration, they are numbered consecutively from the first day of the migration to the end of the migration each day collect every n th sockeye smolt (x th coho smolt) that migrate and place it in a live box located in the stream next to the trap. Remember to begin your daily count with the count you ended with the day before. 1 'The age, weight, and length characteristics of the coho smolt migration are also determined. Procedures followed are the same as the sockeye procedures except coho smolt are not sacrificed for otolith removal. Collect and measure every x th coho smolt. After measurements are complete anesthetized coho are placed in fresh water for recovery and then released to the stream. 1 15

20 2) Keep a daily record of the number of smolts collected in the yellow waterproof notebooks. At any time throughout the migration the total number of smolts collected should equal 1/n th of the total number of sockeye smolts (1/x th of the total number of coho smolts) that have migrated. 3) Each day transfer the smolts that were collected from the live box to a bucket of water. Anesthetize the smolts with MS-222 by adding approximately 1 gram of dry MS-222 per quart of water. Keep the volume of water low to minimize the amount of MS-222 used. MS-222 is toxic and you should use latex gloves when handling anesthetized fish and a dust mask and gloves when handling the dry chemical (see MSDS data sheet in safety mannual). The smolt will be full anesthetized in 2 to 3 minutes. 4) Select an anesthetized smolt and weigh it to the nearest 0. 1 gram. Before you begin weighing, be sure to zero the scale to ensure accurate weights. Next measure the length of the smolt to the nearest millimeter, from the tip of the snout to the fork of the tail as shown below. Record both length and weight on the smolt AWL data sheet (Figure 10). 5) Use a knife to remove 5 to 10 scales from the preferred area of the smolt (Figure 7); i.e. the area two scale rows above the lateral line on a diagonal from the posterior insertion of the dorsal fin to the anterior insertion of the anal fin. With the knife gently brush the blade against the grain of the scale in the preferred area. 6) Arrange 5 or 6 scales in a column on a glass slide. Each column of scales should represent one smolt and they should be arranged consecutively. Try to arrange ten 16

21 columns on the glass slide (i.e.: 10 smolt per slide). On each slide write the following: location, date, species, and sample numbers 7) Place the slide in the appropriate slot in the storage box after it is completed. 8) For all sockeye smolt collected, after the length and weight measurements have been obtained and recorded and the scale samples collected, the otoliths are extracted. Expose the otolith by removing the sockeye smolt's head and carefully peel the skin and opercular plate from the head. With forceps probe the soft tissue exposed when the skin and opercular plate were removed. The otoliths are small solid white structures that can be easily felt with the forceps. 9) Remove the otolith from each side of the head and place in the 1 dram vials provided. Alcohol has already been added to the vials to preserve the otoliths. Write in pencil the date the smolt was collected and the sample number on a small paper tag. Place the tag in the vial, cap and store upright to avoid leaks. 10) Repeat steps 4 through 9 with the next sockeye smolt (steps 4 through 7 with the next coho smolt). 17

22 Preferred Area One Scale Lateral Line One Smolt Fish Creek 6/12/04 # Sockeye Place a MAXIMUM of 10 smolts per slide and DO NOT place samples from different dates on the same slide. Each column of scales comes from the SAME fish. Figure 7: Smolt AWL Procedure 18

23 Data Sheet Completion Procedure A binder with the various data sheets will be provided for you. The data sheets are to remain in the binder. The data sheet binder is to remain in the main camp building not to be taken outside. All data should be transcribed daily from the weather notebook to the data sheets. It is important to remember that all of the information generated by this project is contained in the data sheet binder and the weatherproof notebooks. When filling out data sheets or entering data in the weatherproof notebook, always use a sharp pencil. Do not use a pen as the ink will run if the paper gets wet and will be illegible. Do not erase if you make a mistake but strike a line through the error and write in the data legibly. A zero is a number and is usable data. If you did not make an observation and there is no data write ND on the data sheet. 19

24 Environment Daily Log An example of an Environment Daily Log Sheet is shown in Figure 8. Every day at 5 PM, record weather codes, rain gauge and staff gauge readings and air and water temperature measurements. Each 24 hour sampling period begins at 5 AM and ends the next morning at 5 AM. The date for each 24 hour sampling period is designated by what the calendar date was when the sample period began at 5 AM. The weather codes are explained on the bottom- of the data sheet. Record only the weather that is occurring at the time of the observation. Precipitaion is measured with the rain gauge and recorded to the nearest millimeter. After each observation empty it and clean out the debris. The staff gauge is calibrated in tenths of feet. Read the gage between stream surges and between the crest and trough of surface waves. Temperatures are measured on the Celsius scale. Record air temperature first making sure the thermometer is dry. Water temperatures are measured from the creek at the point of maximum flow. Smolt Daily Log An example of a Smolt Daily Log is shown in Figure 9. For each date on the data sheet enter the total smolt that were counted for that 24 hour time period. This number will be available when you have finished all enumerations for that time period, after the 5 AM count. Mortalities are not included in the daily count but should be recorded in the box marked notes". Designate the species of the mortalities. 20

25 Smolt AWL Data Sheet An example of a Smolt AWL Data Sheet is presented in Figure 10. First fill in the date, species, page number, and location information. Then list the sample number, length and weight in the spaces provided for each smolt measured. Remember sample numbers start consecutively from the beginning of the smolt migration and should continue consecutively until, the end of the migration. Do not fill any information in the "Age" and "Remarks" column. You should complete at least one data sheet every day measurements are collected. Because each sheet only contains 50 spaces for AWL measurements, you may need to complete more than one sheet per day. Never put the measurements from two separate days on one data sheet. 21

26 Figure 8: Environment Daily Log 22

27 Figure 9: Smolt Daily Log 23

28 Figure 10: Smolt AWL Data Sheet 24