Obsolete - AFSC/RACE/EcoFOCI - Ichthyoplankton data collected in support of FOCI assessment surveys and ecosystem observations in the Bering, Beaufort, and Chukchi Seas and the...

The dataset contains records of fish eggs and larvae collected during FOCI assessment surveys. Records include all data pertinent to identify where specimens were collected (lat, lon, date, gear used, max depth of gear, water depth). Specific data on specimens includes scientific name, stage of development, number collected (whole numbers and CPUE), lengths of larvae, and diameters and stages of eggs. In addition, there are comments that explain any irregularities that may have occurred during sample collection; depending on the reason data is being extracted, comments may indicate a sample is not suitable for consideration.

Ichthyoplankton surveys attempt to define specific characteristics of marine populations from early life history strategies to standing biomass estimates. Since the bulk of the fishing industry does not focus directly on the ichthyoplankton component, these surveys can give us a true fishery-independent estimate. Since the introduction of the Egg Production Method or Daily Egg Production (EPM or DEPM) around 1985, we can have an accurate estimate of many of the midwater and pelagic species standing biomass if we have accurate and consistent measurement of the ichthyoplankton along with fishery-independent adult parameters. NOAA Fisheries conducts ichthyoplankton surveys with a wide variety of characteristics. Not only do the target species, and therefore the appropriate sampling methods differ among surveys, but the characteristics of the survey vessels differ which include chartered fishing vessels as well as NOAA research vessels.

Ichthyoplankton surveys have been conducted in many large marine ecosystems (e.g., California Current, Gulf of Alaska, Bering Sea, Georges Bank, Baltic Sea) to generate fishery independent stock estimates, explain variations in recruitment, and identify marine species assemblages. As a result, ichthyoplankton surveys have played a key role in understanding how marine ecosystems function and change over time. The Recruitment Processes Program (initially named Resource Ecology) of the Alaska

Fisheries Science Center (AFSC) has been conducting ichthyoplankton surveys in the Northeast Pacific Ocean and Bering Sea since 1965. During the early years, many projects and research studies focused on various taxa and geographic regions, but a major emphasis for the past 15 years has been the Fisheries Oceanography Coordinated Investigations (FOCI) Program which has sought to understand conditions leading to variation in recruitment among important commercial fish of the Northeast Pacific, with most effort concentrated on Gadus chalcogrammus (Walleye Pollock). More recent Northeast Pacific Global Ocean Ecosystems Dynamics (GLOBEC) studies at AFSC have investigated the hypothesis that spawning in Northeast Pacific Ocean and Bering Sea marine fish populations has evolved along with oceanographic conditions to give rise to distinct groups or assemblages of fish larvae. Our approach is to study these ichthyoplankton assemblages within the framework of their ecosystems. Ongoing investigations continue to focus on interannual variations in distribution and abundance of eggs and larvae in relation to the environment, particularly regime shifts.

Supplemental Information - Data Parameters and Units - Descriptive Information about the Data Parameters and Units.

Parameters returned on samples sent for sorting and identification: identification of fish larvae and eggs to lowest possible taxon, numbers of each taxon, lengths recorded for up to 50 specimens/taxon, stages of up to 100 Walleye Pollock eggs per sample (if requested), volume of entire sample prior to sorting, and numbers of cephalopods removed from each sample. Each taxon has a separate vial; vials are labeled with the station data and name and number of specimens.

Supplemental Information – Methods - Descriptive Information about the methods used.

Each sample is collected with a MARMAP-style, 60 cm bongo frame using 505µm mesh nets. The gear is fished to 200 meters or 10 meters off bottom. Samples from net #1 are preserved in 5% Formalin at sea and later sorted and identified to the lowest possible taxon at the Plankton Sorting and Identification Center in Szczecin, Poland for all fish larvae and eggs to determine the abundance and CPUE for each species. Larvae that are removed from net #2 are counted, recorded, and immediately preserved in 95% ethanol for otolith analysis (age, growth and hatch date distributions of the population) or genetic studies. Detailed instructions for towing and sample handling may be found in the FOCI Field Manual (Brown et al. 1999).

Other gear used included 1-m2 Tucker trawls, sled trawls (modified Tucker trawl towed on the seafloor), Methot nets, Multiple Opening/Closing Net and Environmental Sensing System (MOCNESS), surface-towed trawls (modified Cantrawls), modified beam trawls, rock dredges, Sameoto neuston nets, and dip nets (Tucker, 1951; Sameoto and Jaroszyinski,1969; Wiebe et al., 1976; Methot, 1986; Eisner et al.,2012).

Survey operational procedures

The SeaCat is attached to the wire approximately one meter above the 60- cm bongo frame to provide real-time depth data. The frame is fitted with 505µm mesh nets and 4" PVC codends (with 505µm mesh drain holes). The initial flowmeter readings for each side of the bongo are recorded on the Cruise Operations Database (COD) form along with the station identification information (Figure 2). The nets and codends are inspected for damage before and after each tow. The gear is launched via the starboard winch at 40 meters per minute. During periods of bad weather and heavy surge, the winch operator is instructed to let the wire out at a much slower rate (20 - 30 m/min) to prevent backlash on the winch. The direction of the tow should be such that the wind and swells are taken at a 45 degree angle across the starboard bow to prevent the gear and wire from being run over by the ship and risking entanglement with the centerboard or screw. The depth of the nets are monitored from a dedicated computer inside the ship and commands are given to standby and stop the winch at depth and begin retrieval when the gear has reached 200 meters or 10 meters off bottom. In the event that the SeaCat suddenly fails during a tow and there will not be time to repeat the tow, the wire out vs wire angle chart (see Brown et al. 2009) may be used to continue the tow (Table 1).

The gear is brought back to the surface at 20 m/min. The ship speed is maintained between 1.5 and 2.0 knots and is continually adjusted to maintain a 45 degree wire angle. These angles are radioed to the Bridge by either the Survey Tech or a scientist who uses a hand held inclinometer to determine wire angle. The wire angles must be kept between 35 and 55 degrees to insure proper fishing of the gear. Low wire angles result in the frame moving too slow (larvae may avoid the nets). High wire angles result in the net moving too fast (larvae may be extruded through the net or avoid the net due to an increase in the frontal pressure wave). If the wire angle is outside these tolerances (35 < x < 55 º) for more than 30 seconds, then the catch should be discarded and the tow repeated.

When the nets surface, they are brought aboard and quickly washed. The nets and codends are inspected for damage and possible sample loss. The final flowmeter readings are recorded for each side of the bongo. The total flowmeter revolutions (final revolutions minus initial revolutions) for each flowmeter are calculated before the sample is preserved and should be within 100 - 200 counts of each other. Since net 1 is the only net that is used quantitatively and if there is a time restriction that does not allow the tow to be repeated, net 2 may be used in its place if there is a suspected problem with the flowmeter (jellyfish tentacles wrapped around the flowmeter, slow gears, damaged codend, etc.). Any changes to regular procedures, such as substituting net 2 for net 1, should be noted on the COD form. Problem flowmeter(s) should be replaced before the next station. Under normal operating conditions, the codend from net 2 is immediately taken into the laboratory and sorted for larvael over an ice bed to reduce possible shrinkage of the fish larvae (Theilacker and Porter, 1995). Larvae are counted and put into a vial of 95% ethanol for otolith and/or genetics studies. The codend from net #1 is the quantitative sample (recorded as QTowF on the COD form) that will be used for the larval abundance estimates. The codend contents of net #1 are carefully poured into a 505 mm mesh sieve to reduce the fluid enough to pour the sample into a 32 oz jar and preserve it with 50 ml of 37% formaldehyde and 20 ml of sodium borate used to buffer the solution (see Dougherty et al. 2009 for complete details on sample handling). In the event that the above specifications have not been met, or it is suspected that the gear may have hit bottom or some of the sample was lost during the tow due to net or codend damage, the tow should be repeated. The scientists are responsible for recording tow time, maximum depths, and all other data required for the COD form. All station data is entered into a relational database (COD) soon after the tow. During the cruise, scientists will verify that the station data have been correctly entered by comparing the paper form with an edit form printed by the COD application. A digital record of the tow

trajectory and maximum depth is archived for future reference (SeaCat files).

Alaska fisheries Science Center ichthyoplankton sorting protocols

Processing

Processing for an ichthyoplankton cruise is carried out in several steps: measuring the volume of the plankton in each sample, sorting out and counting all fish eggs and larvae, measuring fish larvae, identifying all fish eggs and larvae, staging (aging) some fish eggs, and putting fish eggs in 5% Formalin and larvae in 70% ethanol (mixed from 95 % ethanol with no additives).

Volume Measurement

Excess liquid from each sample is removed and then the remaining contents are poured into a 500-ml graduated cylinder. Enough preservative is then added or subtracted to bring the level of the liquid to an even milliliter. A funnel is placed in another clean 500-ml graduated cylinder. A draining cone of 0.333 mm or smaller mesh is placed in the funnel. The plankton and formalin are poured into the draining cone. The plankton is retained in the cone while the liquid drains into the cylinder. The plankton is considered drained when the interval between drops from the bottom of the cone increases to 15 seconds. The volume of the drained liquid in the cylinder is subtracted from the initial volume of plankton plus liquid. The difference is the volume of the plankton. These data are recorded and the plankton is returned to the jar with preservative in preparation for sorting.

Sorting

Each sample delivered to the sorting laboratory is sorted for all fish eggs and larvae. Although techniques may vary with individual sorters, the general method for sorting is as follows: the plankton is separated from its preservative by straining it through a nylon draining-cone. The cone containing the inside jar label and the plankton is rinsed gently and then suspended in a one-liter beaker filled over ½ the way up the cone with fresh water containing a few drops of concentrated formalin. Small amounts (~ 30 ml) of plankton are spooned into 50-mm petri dishes for sorting.

Each dish is examined under a dissecting microscope at about 7-10X magnification. All fish eggs and larvae are picked out with pipettes and/or fine quality (stainless steel) “soft touch” forceps and transferred to their appropriately-labeled dishes. When the fish eggs and larvae have been sorted and checked, the remaining contents of the dish are poured into a "sorted" 1.5-liter beaker containing fresh water with a few drops of concentrated formalin. This procedure is repeated until the entire sample has been examined.

When there are head and tail sections of larvae, the number of "larvae removed" includes only the head sections. Tail sections that can be identified are placed in the appropriate vials, but are not counted in the total number. Head and tail sections that cannot be identified but are in good condition are placed in vials labeled “Unidentified”. Head and tail sections that are too damaged to be identified are placed in vials labeled “Disintegrated”. The number of larvae should be recorded in all separated vials including

“Unidentified” and “Disintegrated”.

Quality Control

Approximately 10% of each sample is resorted by a senior staff member. If two or more fish larvae and/or eggs are found, the entire sample is resorted; the results of the quality control will be recorded on the ISR.

Identification of Fish Eggs and Larvae

Taxonomic Codes 2015-- The AFSC 3-digit taxonomic codes will be used for eggs and larvae. Updated code lists are provided yearly. The identifier will assign each specimen to the lowest taxonomic level possible.

Unidentified (Code 139): Those specimens which cannot be taken to at least the Order level, but which are in identifiable condition, will be classified as Unidentified (code 139). Total numbers are recorded.

Disintegrated (Code 145): Those larvae in such a poor state that they are impossible to identify are called Disintegrated (code 145). Total numbers are recorded.

Head and tail sections are sometimes present and may possibly be identified. Head sections that can be identified should be included as a number in the total count for whole specimens; if tail sections are recognizable to species, include them in the appropriate species vial, but counting tails is not necessary. If either heads or tails are unrecognizable, count heads and record as “Disintegrated”.

Fish Larvae

Trained sorters may have made identifications and measurements of fish larvae for certain commonly occurring species. After checks by senior staff members, these data will be combined with those from the full identification described below. Larvae are identified to the lowest taxonomic category possible. Identifications are made by comparing morphological characters of the larvae (e.g., body shape, meristic, pigmentation, special larval characters) with published descriptions, especially the Laboratory Guide to Early Life History Stages of Northeast Pacific Fishes (Matarese et al., 1989; web version http://access.afsc.noaa.gov/ichthyo/index.php).

Larvae are stored in 70% ethanol in 3-dram vials. Larger containers (1, 2, 4, and 8 ounce jars) provided by AFSC should be used for large numbers of larvae and juvenile fishes. Vials and jars should be less than ½ full of larvae and larger juveniles.

Enumeration and Measuring-- All larvae are counted and, if intact, up to 50 are measured for standard length. All larvae of each taxon should be measured when the number of individuals is less than 50. When counts exceed 50, a randomly selected

sub-sample of 50 individuals should be measured.

Fish Eggs

Enumeration--All fish eggs are sorted, counted, and results recorded. In samples with more than 5,000 eggs, as estimated by eye, a volumetric procedure to estimate the number of eggs is performed as follows. (These samples usually contain a preponderance (>95%) of Gadus chalcogrammus eggs, and in many cases are samples designated for egg staging.) First, 100 eggs are picked out randomly and placed in a separate vial for staging. Then 900 eggs are counted and their settled volume is determined in a 5- or 10-ml graduated cylinder.

The volume of the remainder of the eggs is determined. The total volume equals the sum of the volume of the 900 eggs plus the volume of the remaining eggs.

Total Eggs in Sample = ((Total Volume/Vol. of 900 eggs) 900) + 100

At times there have been very large numbers of eggs collected at a station, filling jars from ¼ to over ¾ full of eggs. In these instances it is suggested that after fish larvae have been removed from the sample, that the sample be split as many times as necessary to obtain an aliquot equal to the volume of a 1 oz. jar. Eggs in the 1 oz. aliquot should be enumerated volumetrically as described above and identified.

Identification--Fish eggs will be identified to lowest taxonomic category possible in all. AFSC 3-digit taxonomic codes will be used for all identified eggs. The manipulation of the specimens, their labeling, and the microscopic techniques are similar to those used for larvae. Fish eggs are identified by comparing their morphological characters (e.g., egg diameter, oil globule presence and size, chorion characters, pigment, embryonic characters) with descriptions in the lab guide. A chart of the egg diameters of the most commonly occurring species is provided.

Egg Staging-- For selected cruises, Gadus chalcogrammus eggs are to be staged according to a 24-stage scheme. For these samples, all G. chalcogrammus eggs are identified and counted (see above for procedures when >5,000 eggs). Then 100 eggs are selected randomly and staged (all eggs in samples with <100 eggs). These data are recorded on the Egg Staging Form.

Supplemental Information – Instruments - Descriptive Information about the instruments and equipment used.

Pressure sensors:

A SeaBird SeaCat (SBE-19) is attached to the wire approximately 1 meter above the 60 cm bongo frame. Real time display of conductivity, temperature, and depth is monitored in remotely on a designated computer display.

Flowmeter calibrations:

General Oceanics flowmeters are mounted in both mouths of the bongo frame.

All flowmeters are annually calibrated (see procedures used by Smith and Richards, 1977).

Supplemental Information - Sampling Scales and Rates - Descriptive Information about the sampling spatial and temporal scales and rates.

Supplemental Information - Error Analysis - Descriptive Information about the error analysis.

Supplemental Information - Provenance and Historical References -

Descriptive Information about the provenance, historical data, key information packaged elsewhere.

NATIONAL MARINE FISHERIES SERVICE INSTRUCTION 04-105-01

JANUARY 15, 2003

Science and Technology

Standards and Protocols for Surveys

NOAA FISHERIES PROTOCOLS FOR ICHTHYOPLANKTON SURVEYS

This publication is available at: http://www.nmfs.noaa.gov/directives/.

Dougherty, A., C. Harpold, and J. Clark. 2009. Eco-FOCI Field Manual. NOAA Fisheries, Alaska Fisheries Science Center.

Smith, P.E. and S.L. Richardson. 1977. Standard techniques for pelagic fish egg and larva surveys. FAO Fish. Tech. Pap. No. 175: 1-99.

Theilacker, G.H. and S.M. Porter. 1995. Condition of larval walleye pollock, Theragra chalcogramma, in the western Gulf of Alaska assessed with histological and shrinkage indices. Fisheries Bulletin 93: 333-344.