NOAA Technical Memorandum NMFS-NE-156

This report series represents a secondary level of scientifiic publishing. All issues

employ thorough internal scientific review; some issues employ external scientific

review. By design, reviews are transparent collegial reviews, not anonymous peer

reviews. All issues may be cited in formal scientific communications.

U. S. DEPARTMENT OF COMMERCE

William M. Daley, Secretary

National Oceanic and Atmospheric Administration

D. James Baker, Administrator

National Marine Fisheries Service

Penelope D. Dalton, Assistant Administrator for Fisheries

Northeast Region

Northeast Fisheries Science Center

Woods Hole, Massachusetts

May 2000

George R. Bolz1, James Patrick Monaghan, Jr.2, Kathy L. Lang1,

Randall W. Gregory2, and Jay M. Burnett1

Proceedings of the

Summer Flounder Aging Workshop,

1-2 February 1999, Woods Hole, Massachusetts

1National Marine Fisheries Serv., Woods Hole Lab., 166 Water St., Woods Hole, MA 02543

2North Carolina Div. of Marine Fisheries, P.O. Box 769, Morehead City, NC 28557
NOTE ON SPECIES NAMES

The NMFS Northeast Region’s policy on the use of species names in all technical communications is generally to follow

the American Fisheries Society’s lists of scientific and common names for fishes (i.e., Robins et al. 1991a), mollusks (i.e.,

Turgeon et al. 1998b), and decapod crustaceans (i.e., Williams et al. 1989c), and to follow the Society for Marine

Mammalogy's guidance on scientific and common names for marine mammals (i.e., Rice 1998d). Exceptions to this policy

occur when there are subsequent compelling revisions in the classifications of species, resulting in changes in the

names of species (e.g., Cooper and Chapleau 1998e, McEachran and Dunn 1998f).

a

Robins, C.R. (chair); Bailey, R.M.; Bond, C.E.; Brooker, J.R.; Lachner, E.A.; Lea, R.N.; Scott, W.B. 1991. Common and scientific names

of fishes from the United States and Canada. 5th ed. Amer. Fish. Soc. Spec. Publ. 20; 183 p.

b

Turgeon, D.D. (chair); Quinn, J.F., Jr.; Bogan, A.E.; Coan, E.V.; Hochberg, F.G.; Lyons, W.G.; Mikkelsen, P.M.; Neves, R.J.; Roper,

C.F.E.; Rosenberg, G.; Roth, B.; Scheltema, A.; Thompson, F.G.; Vecchione, M.; Williams, J.D. 1998. Common and scientific names of

aquatic invertebrates from the United States and Canada: mollusks. 2nd ed. Amer. Fish. Soc. Spec. Publ. 26; 526 p.

c

Williams, A.B. (chair); Abele, L.G.; Felder, D.L.; Hobbs, H.H., Jr.; Manning, R.B.; McLaughlin, P.A.; Pérez Farfante, I. 1989. Common

and scientific names of aquatic invertebrates from the United States and Canada: decapod crustaceans. Amer. Fish. Soc. Spec. Publ. 17; 77 p.

d

Rice, D.W. 1998. Marine mammals of the world: systematics and distribution. Soc. Mar. Mammal. Spec. Publ. 4; 231 p.

e

Cooper, J.A.; Chapleau, F. 1998. Monophyly and interrelationships of the family Pleuronectidae (Pleuronectiformes), with a revised classification.

Fish. Bull. (U.S.) 96:686-726.

f

McEachran, J.D.; Dunn, K.A. 1998. Phylogenetic analysis of skates, a morphologically conservative clade of elasmobranchs (Chondrichthyes:

Rajidae). Copeia 1998(2):271-290.
Page iii

Contents

Abstract .............................................................................................................................................................................. v

Introduction ........................................................................................................................................................................ 1

Methods ............................................................................................................................................................................. 1

Results ................................................................................................................................................................................ 2

Conclusions and Recommendations ................................................................................................................................... 3

References Cited ................................................................................................................................................................. 4

Tables

Table 1. Number of fish assigned by the NEFSC and NCDMF to various age classes based on original age

determinations by each agency of the 50-fish sample of summer flounder scales collected during the

NEFSC and MDMF bottom trawl surveys in 1997 ............................................................................................. 5

Table 2. Details of the 120-fish NCDMF summer flounder scale sample exchange with the NEFSC, including fish

size and original and adjusted age determinations ............................................................................................. 6

Table 3. List of participants at the Summer Flounder Aging Workshop held on 1 and 2 February 1999 in Woods

Hole, Massachusetts ......................................................................................................................................... 7

Table 4. Details of the 50-fish summer flounder scale sample exchange with the NCDMF, including fish size, month

of capture, source of specimens, geographic area of collection, original and adjusted age determinations,

and workshop resolution of, and/or reason for, disagreement between agencies.............................................. 8

Table 5. Number of fish assigned by the NEFSC and NCDMF to various age classes based on the 1999 workshop

re-aging by each agency of the 50-fish sample of summer flounder scales ......................................................10

Figures

Figure 1. Scale image from a 34-cm male summer flounder captured in May 1995 during the MDMF spring inshore

bottom trawl survey, which was aged by the NEFSC as age 2 and by the NCDMF as age 1 in the original

50-fish NEFSC exchange sample. The first annulus is indicated. Workshop participants agreed on age 2 .....11

Figure 2. Scale image from a 33-cm summer flounder collected on 4 March 1997 during the North Carolina winter

commercial fishery, which was aged by the NCDMF as age 1 and by the NEFSC as age 2 in the 120-fish

NCDMF exchange sample. The first annulus is indicated. Workshop participants agreed on age 1 ..............12

Figure 3. Statistical areas used by the NEFSC for recording the locations of harvests of marine fisheries resources

off the northeastern United States ....................................................................................................................13

Figure 4. Scale image from a 33-cm male summer flounder captured in March 1996 during the NEFSC spring bottom

trawl survey, which was aged by the NEFSC as age 1 and by the NCDMF as age 2 in the original 50-fish

NEFSC exchange sample. Both NCDMF annuli are indicated; NEFSC considers the first mark to be an early

life history event. Workshop participants did not resolve the disagreement ...................................................14

Figure 5. Scale image from a 50-cm fish collected in June 1995 by the NEFSC from the commercial fishery, which was

aged by the NCDMF as age 3 and by the NEFSC as age 2. The first two NCDMF annuli are indicated;

NEFSC considers the first mark to be an early life history event. Workshop participants did not resolve

the disagreement ...............................................................................................................................................15

Acronyms

MDMF = Massachusetts Division of Marine Fisheries

NCDMF = North Carolina Division of Marine Fisheries

NEFSC = Northeast Fisheries Science Center

ODU = Old Dominion University
Page v

ABSTRACT

A workshop to review summer flounder aging techniques was conducted at the National Marine Fisheries Service’s

Northeast Fisheries Science Center (NEFSC) in Woods Hole, Massachusetts, on 1 and 2 February 1999. The workshop

convened to address: 1) the poor results of comparative readings from a 1997 scale sample exchange between age readers at

the NEFSC and North Carolina Division of Marine Fisheries (NCDMF); and 2) concerns over aging accuracy expressed in

recent stock assessments and in a review of those assessments by the National Research Council.

The workshop identified three factors which contributed to the poor results of comparative readings. The majority

of age determination disagreements were related to differing age-reading conventions used by each agency with regard to

the marginal increment (i.e., growth beyond the last annulus) on the scales. Correcting for this discrepancy in convention

increased agreement rates from about 53% to over 80%. The origin of the convention problem appears to be differences in

the timing of annulus formation between fish inhabiting the Cape Hatteras region (i.e., during January-March) and fish in the

Southern New England region (i.e., during May-July).

The second source of disagreement between agencies was related to the choice of a first annulus in some, but not

all, fish. The third source of disagreement occurred when NEFSC age readers determined a scale event to be a “check” as

opposed to NCDMF age readers determining it to be an annulus.

Workshop participants concluded that future exchanges should occur on a regular basis to ensure uniformity of

aging conventions and age interpretations. Additionally, it was agreed that analysis of samples and/or data for young-ofthe-year summer flounder (possibly archived by state or university researchers) might resolve uncertainties regarding firstannulus location.
Page 1

INTRODUCTION

Difficulties in aging summer flounder, Paralichthys

dentatus, have been ongoing for many years. Aging disagreements for this species were noted in an October 1979

literature review by the Mid-Atlantic Fishery Management

Council’s State/Federal Summer Flounder Scientific and Statistical Committee, and were discussed in a May 1980 workshop convened by that committee in Woods Hole, Massachusetts (Smith et al. 1981), to resolve the noted discrepancies. Investigators from state, federal, and university laboratories participated in the 1980 workshop. Two conclusions reached at that 1980 workshop were: 1) mean length

at age 1 was calculated to be 17-18 cm; and 2) great latitudinal variation was found with respect to edge type, length at

age, and growth rate. Although six types of scale growth

patterns were categorized, the 1980 workshop determined

that the limited number of scales available for examination

did not allow firm conclusions about growth pattern differences among areas.

In 1989, at the Ninth NEFC Stock Assessment Workshop, members of that workshop’s Summer Flounder Working Group raised concerns again regarding differences in

aging protocols between state and federal laboratories

(Northeast Fisheries Center 1989). A workshop was convened in June 1990 (Almeida et al. 1992) to reach consensus regarding the interpretation of scale growth patterns.

Several studies (Able et al. 1990; Szedlmayer et al. 1992)

which had been conducted between the 1980 and 1990 workshops determined that summer flounder growth during the

first year was much greater than previously thought and

could explain some of the confusion in determining the first

annulus. Participants at the 1990 workshop examined approximately 150-200 scale samples and agreed upon aging

criteria. Noteworthy was the conclusion that annulus formation in the more northerly waters (i.e., Southern New

England and New Jersey) occurred in late spring - early

summer, while further south it occurred as early as January

or February. The 1990 workshop participants recommended

that formal age structure exchanges be initiated to achieve

consistency.

Accordingly, an exchange of scale impressions occurred

in June 1997 between the National Marine Fisheries Service’s

Northeast Fisheries Science Center (NEFSC) and the North

Carolina Division of Marine Fisheries (NCDMF), the only

two agencies actively performing production aging of summer flounder at that time. The exchange consisted of two

parts: 1) a sample of 50 fish exhibiting temporal and spatial

variation which had been selected from NEFSC and Massachusetts Division of Marine Fisheries (MDMF) bottom

trawl surveys and from the commercial fishery throughout

the Northeast; and 2) a 120-fish sample from the winter

commercial fishery in the North Carolina - Virginia region.

Comparative reading results from the exchange indicated a poor level of agreement (i.e., approximately 53%;

Tables 1 and 2) between the agencies. Concern regarding

the implications of potential aging problems on future stock

assessments was raised during a review of the most recent

summer flounder assessment at a National Research Council committee meeting on improving the collection and use

of fisheries data, held on 25 and 26 January 1999 in Washington, D.C. To determine the cause of, and to resolve,

these aging disagreements, age readers from the NEFSC

and NCDMF conducted a workshop during 1-2 February

1999 in Woods Hole, Massachusetts. Also present at the

1999 workshop were representatives of Old Dominion

University’s (ODU’s) Fish Age & Growth Laboratory, which

had recently been contracted to perform production aging

of summer flounder from the Chesapeake Bay region (Table

3).

The objectives of the 1999 workshop were to: 1) identify factors resulting in age determination discrepancies

between the NEFSC and NCDMF; 2) resolve, to the extent

possible, disagreements in the exchange samples; and 3)

initiate a course of action to ensure consistency in aging

methods and future age interpretations. This report summarizes the activities and results of the 1999 workshop, and

offers recommendations for further consideration.

METHODS

PRECISION

In preparation for the 1999 workshop, NEFSC age readers conducted a blind reading (i.e., sex and length of fish

unknown, but date of collection known) of the 120-fish

NCDMF samples constituting the 1997 exchange materials

to determine levels of precision with respect to the original

age determinations. The NCDMF age readers conducted a

blind reading of the 50-fish NEFSC sample during the course

of the workshop.

AGE DETERMINATIONS

Aging criteria described by Dery (1988) and accepted by

the 1990 Summer Flounder Aging Workshop participants

(Almeida et al. 1992) were reviewed in detail during the 1999

workshop. Annuli generally consist of “cutting-over” marks

which must be continuous through the scale’s lateral field

and into the ctenii (Figure 1). The age of a fish is determined first by counting the number of annuli present and

then by considering the amount of growth beyond the last

annulus (i.e., “edge” or “ + ” growth) at the time of sample

collection. Age is then determined relative to the convention of the 1 January birthdate used for assessment purposes. For example, a fish which has formed three annuli

and has additional growth beyond the third annulus would

be considered age 3+ if collected on 31 December, but age 4

on 1 January.
Page 2

During the 1999 workshop, summer flounder scale impressions (see Penttila et al. 1988 for details regarding preparation of scale impressions) were viewed using a Leitz TP

300 Contour Microprojector at a magnification of 50X and

occasionally 20X. It was noted that the NCDMF normally

views and measures images of summer flounder scale impressions at a magnification of 24X.

Workshop participants agreed to view in its entirety

the 50-fish NEFSC exchange sample as the basis for the

workshop (hereafter referred to as the “workshop sample”),

and as much of the 120-fish NCDMF exchange sample as

time allowed.

For each fish, five or six scale impressions were viewed

silently by participants until they indicated that an age determination had been made. These age determinations were

then compared to those provided by the NEFSC and NCDMF

during the exchange exercise, and any discrepancies were

discussed until either a consensus age was obtained or an

impasse was reached. Additional time was budgeted during the workshop to: 1) view summer flounder otoliths for

consideration as an alternative aging structure; 2) view other

scale sample images as necessary to illustrate specific

points; and 3) to generate annotated images illustrating

workshop examples and results using an OPTIMAS Image

Analysis System at magnifications of 12.5X and 20X.

RESULTS

PRECISION

A re-reading of the workshop sample by NEFSC age readers resulted in a precision of 92% when compared with their

original reading. After further review of this sample, age

determinations by the NEFSC age readers were adjusted

upward by 1 yr for three fish. One other fish was adjusted

downward 1 yr; however, this fish was subsequently discarded from further analysis at the workshop when consensus with NCDMF age readers could not be reached.

Precision of NCDMF age readers was 96% (Table 4).

Age determinations by the NCDMF age readers were adjusted downward for two fish.

AGE DETERMINATIONS

Results for the 50-fish workshop sample are listed in Tables

4 and 5, with workshop resolution of disagreements or the

specific reason for unresolved disagreements noted in the

“Workshop Resolution” column of Table 4.

Scale impression quality was similar in each exchange

sample and was not a factor for any disagreements in age

determinations. Three factors were identified, though, which

contributed to age determination disagreements. The factor which occurred most frequently and had the greatest

impact on exchange results was a difference in conventions

used by each agency with respect to the marginal increment (i.e., growth beyond the last annulus). NEFSC age

readers assume that annulus formation occurs during MayJuly (Dery 1988); therefore, scale samples collected on winter and spring surveys or during the first and second quarters of the calendar year should have a wide marginal increment prior to annulus formation. The algorithm invoked by

the NEFSC for this portion of the year – prior to 1 July – is

to count the number of annuli present and also to count the

edge. Thus, a fish whose scale contains three annuli would

be assigned age 4 during 1 January - 30 June. However,

since annuli form in January-March for fish in the North

Carolina - Virginia region, NCDMF age readers assign an

age based on the number of annuli present, assuming that

the last-formed annulus occurred after 1 January of the collection year.

How this observed difference in annulus formation results in age determination “disagreements” is best illustrated through the use of some 1999 workshop samples.

Figure 1 shows a scale image from a 34-cm male summer

flounder captured in May 1995 during the MDMF spring

inshore bottom trawl survey (Table 4, ID 6). Each agency

agreed that one annulus was present; however, NEFSC age

readers assigned an age of 2 yr based on the width of the

marginal increment and the expectation that a second annulus would be forming in the next month or so. NCDMF age

readers, who typically age fish which have formed annuli

during January-March, interpreted the increment to be current-year growth, and assigned an age of 1 yr. The consensus of workshop participants was that the width of the marginal increment represented nearly 1 yr of growth beyond

an annulus formed during the previous May-July, rather

than 3-4 mo of growth beyond an annulus formed during

January, and thus the scale edge should be counted, resulting in an age of 2 yr. Correcting for this difference in convention accounted for 40% of the age determination disagreements in the original 50-fish NEFSC exchange sample

(Table 4).

As the workshop progressed to the 120-fish NCDMF

exchange sample, the observed difference in annulus formation discussed in the preceding paragraph was identified as resulting in an opposite type of increment interpretation discrepancy. Figure 2 shows a scale image from a 33-

cm fish collected on 4 March 1997 from the Cigar Shoal

region off the North Carolina - Virginia border by the winter

commercial fishery (Table 2, ID 7). Age readers from the

NEFSC assigned an age of 2 yr, and NCDMF 1 yr, for the

same reasons stated earlier. However, in this instance, the

width of the marginal increment is relatively small, supporting a January annulus formation, and the consensus of the

workshop was that growth beyond the annulus represented

current year growth and should not be used to increment

the age as done by the NEFSC. Although time constraints

did not allow the workshop to view the entire NCDMF exchange sample, it is likely that 26 of 51 age determination

disagreements (51%; Table 2) resulted from the NEFSC prac-
Page 3

tice of counting the edge during this period of the calendar

year.

Given the importance of assumptions about the timing

of annulus formation to the 1999 workshop results, participants reviewed samples to verify the observed variability

in this phenomenon. A 6-mo range for annulus formation

was documented. A 25-fish sample commercially caught in

NEFSC Statistical Area 521 (Figure 3) and obtained in

Chatham, Massachusetts, on 6 July 1997 (NEFSC commercial fishery weighout document #275249) contained numerous scales on which an annulus had just formed, or was

forming, on the scale edge. Similarly, annulus formation

just inside scale edges was observed in a 25-fish sample

commercially caught in NEFSC Statistical Area 635 and obtained in Virginia on 7 January 1997 (weighout document

#600007).

A second source of disagreement between agencies

occurred in the choice of a first annulus in some, but not all,

fish. In seven instances (14%), NCDMF age readers increased the total age by 1 yr by selecting a first annulus

considered by NEFSC age readers to be too small to be a

true annulus, and to be a “check” (i.e., temporary halt in

growth) marking an early life history event. For example,

Figure 4 shows the scale image of a 32-cm male summer

flounder captured in March 1996 during the NEFSC spring

bottom trawl survey (Table 4, ID 17), in which the NCDMF

observed two annuli, but which the NEFSC aged as 1 yr.

Figure 5 shows the scale image of a 50-cm fish captured in

June 1995 by the Southern New England commercial fishery (Table 4, ID 38), in which, again, the NCDMF observed

two annuli, but which the NEFSC aged as 1 yr. In other

cases, each agency selected different scale events as the

first annulus, which did not alter agreement on a total age,

but would bias length-at-age estimates determined from

back-calculation analyses.

The third source of age determination disagreements

occurred when the two agencies differed as to whether certain scale events constituted an annulus or a check. The

NCDMF tended to count such marks if they continued into

the lateral scale field, whereas the NEFSC rejected these

marks if they were weaker in the lateral field than adjacent

marks, or, if their spacing from preceding annuli was not

within normal expectations.

CONCLUSIONS AND

RECOMMENDATIONS

Workshop participants concluded that, in general and relative to other species, summer flounder is difficult to age,

due in part to its extensive range and migratory habits.

Annuli in scales are often weak or ambiguous. Review of

whole and sectioned otoliths prepared by ODU suggested

that otoliths may be useful in some instances, particularly

for older fish. However, due to the unavailability of commercial samples because of dealers’ preference that fish not

be cut, otoliths have not been routinely used. Despite these

difficulties, workshop participants agreed that summer flounder can be reliably aged using scales, given adequate precautions discussed in succeeding paragraphs.

Workshop participants concluded that the majority of

aging disagreements in the two exchange samples arose

from the interpretation of marginal scale increments relative

to the highly variable timing of annulus formation observed

for summer flounder throughout its range. The protracted

period of annulus formation, 6 mo or more, is atypical of

most species. Additionally, it appears that the biological

mechanism for annulus formation in different groups of fish

may differ as well; the formation of annuli coincides with

the late spring inshore migration of fish in the northern

portion of the species’ range, but, for fish forming annuli in

January-March, the event appears to occur when the fish

are offshore. If the phenomenon occurred along a latitudinal gradient, then decisions about growth beyond the last

annulus could be simplified to some extent, but the observation from NCDMF tagging studies that fish from different geographical regions are mixing offshore during winter

months confounds any simple approach to setting up aging conventions. This confounding poses less of a problem for the NCDMF, for which production aging is based

primarily on samples obtained from the winter fishery in

that region. However, the NEFSC must exert extreme care in

evaluating marginal increment width in each individual

sample, given the spatial and temporal nature of the samples

they receive from research vessel surveys and the commercial fishery.

The workshop also concluded that more attention must

be given to consideration of first-year growth and the location of the first annulus. The NCDMF consistently applies

criteria of “cutting-over” and intersection with the ctenii in

selecting the first annulus. In order to help locate the first

annulus, NEFSC age readers rely more on a pattern of checks

thought to mark early life history events. Workshop participants agreed that analyses of material from juvenile fish,

possibly archived by state and university researchers, might

assist age readers in interpreting first-year growth patterns

and first annulus selection.

The following recommendations were made at the conclusion of the workshop:

1. Sample exchanges should continue on a regular basis

between the NEFSC and the NCDMF, beginning with

samples from North Carolina’s 1998 winter fishery and

the NEFSC’s 1998 winter, spring, and autumn bottom

trawl surveys. It was suggested that age readers from

ODU also participate in the exchanges to ensure uniformity of aging methods for the species.

2. Appropriate representatives from the NEFSC, NCDMF,

and ODU should inquire as to the availability of samples

and/or data for young-of-the-year summer flounder in

order to conduct analyses of first-year growth.
Page 4

REFERENCES CITED

Able, K.W.; Matheson, R.E.; Morse, W.W.; Fahay, M.P.; Shepherd, G. 1990. Patterns of summer flounder, Paralichthys

dentatus, early life history in the Mid-Atlantic Bight and

New Jersey estuaries. Fish. Bull. (U.S.) 88(1):1-12.

Almeida, F.P.; Castaneda, R.E.; Jesien, R.; Greenfield, R.E.;

Burnett, J.M. 1992. Proceedings of the NEFC/ASMFC

Summer Flounder, Paralichthys dentatus, Aging Workshop, 11-13 June 1990, Northeast Fisheries Center, Woods

Hole, Mass. NOAA Tech. Memo. NMFS-F/NEC-89; 7 p.

Dery, L.M. 1988. Summer flounder, Paralichthys dentatus.

Chapter 15 in: Penttila, J.; Dery, L.M., eds. Age determination methods for Northwest Atlantic species. NOAA

Tech. Rep. NMFS 72:97-102.

[Northeast Fisheries Center.] 1989. Report of the Fall 1989

NEFC Stock Assessment Workshop (Ninth SAW). Northeast Fish. Sci. Cent. Ref. Doc. 89-08b; 71 p. Available

from: National Marine Fisheries Service, 166 Water St.,

Woods Hole, MA 02543.

Penttila, J.; Nichy, F.; Ropes, J.; Dery, L.M.; Jearld, A., Jr. 1988.

Methods and equipment. Chapter 3 in: Penttila, J.; Dery,

L.M., eds. Age determination methods for Northwest

Atlantic species. NOAA Tech. Rep. NMFS 72:7-16.

Smith, R.W.; Dery, L.M.; Scarlett, P.G.; Jearld, A., Jr. 1981.

Proceedings of the Summer Flounder (Paralichthys

dentatus) Age and Growth Workshop, 20-21 May 1980,

Northeast Fisheries Center, Woods Hole, Massachusetts.

NOAA Tech. Memo. NMFS-F/NEC-11; 30 p.

Szedlmayer, S.T.; Able, K.W.; Rountree, R.A. 1992. Summer

flounder, Paralichthys dentatus, growth and temperature

induced mortality during the first year in southern New

Jersey. Copeia 1992:120-128.
Page 5

Table 1. Number of fish assigned by the NEFSC and NCDMF to various

age classes based on original age determinations by each agency

of the 50-fish sample of summer flounder scales collected during

NEFSC and MDMF bottom trawl surveys in 1997. (Number of

assignments in agreement are in bold underlined numerals.)

________________________________________________________

 NCDMF Age NEFSC Age Determinations

Determinations 012345

________________________________________________________

0 1 1

1 1 11 5

2 2 8 2

3 6 4

4 3 1

5 12 1

_____________

Number of fish: 50

Number aged by readers from both agencies: 49

Number of agreements: 26 (53%)

________________________________________________________
Page 6

Table 2. Details of the 120-fish NCDMF summer flounder scale sample exchange with the NEFSC, including fish size and

original and adjusted (in parentheses) age determinations. All fish were collected on 4 March 1997 from Cigar

Shoal off North Carolina.

___________________________________________________________________________________________

 Total Total Total

 Length Age Determinationsa Length Age Determinationsa Length Age Determinationsa

ID (cm) NCDMF NEFSC ID (cm) NCDMF NEFSC ID (cm) NCDMF NEFSC

___________________________________________________________________________________________

1 33 2 2

2 33 1 2b

3 34 2 1

4 33 2 1

5 35 1 1

6 36 2 2

7 33 1 2b

8 33 2 2

9 35 2 2

10 35 2 2

11 34 2 2

12 33 NA 2

13 34 1 2b

14 33 1 2b

15 35 1 1

16 36 1 1

17 32 2 2

18 34 2 2

19 36 1 2b

20 33 1 2b

21 34 2 2

22 36 NA 2

23 34 2 2

24 33 1 2b

25 35 1 2b

26 36 2 2

27 33 1 1

28 36 2 2

29 33 2 2

30 33 2 2

31 35 1 2b

32 36 1 2b

33 36 2 2

34 36 2 2

35 37 2 2

36 38 1 2b

37 38 2 2

38 37 1 2b

39 38 1 2b

40 41 2 2

41 37 2 2

42 37 2 2

43 38 2 2

44 37 3 2(3)

45 36 NA 2

46 36 1 2b

47 37 1 2b

48 35 2 3b

49 35 2 2

50 41 2 2

51 34 2 2

52 41 2 3b

53 38 1 NA

54 34 2 2

55 36 1 2b

56 38 2 2

57 38 2 3b

58 40 1 2b

59 37 2 3b

60 39 NA NA

61 43 2 3b

62 48 2 3b

63 46 2 3b

64 49 4 4

65 47 NA 3

66 51 4 3(4)

67 55 4 4

68 53 5 4

69 48 4 3

70 54 6 4

71 52 4 3

72 49 4 4

73 49 4 3

74 51 3 3

75 47 3 3

76 48 4 4

77 54 4 3

78 45 5 4

79 47 5 3

80 50 5 4

81 50 4 3

82 54 4 4

83 51 4 3

84 49 5 4

85 45 4 4

86 51 4 4

87 47 NA 4

88 51 4 4

89 49 NA 3

90 47 4 4

91 47 4 4

92 54 4 4

93 52 5 3

94 55 3 3

95 44 3 3

96 54 4 4

97 49 4 3

98 50 5 NA

99 49 4 3

100 57 4 4

101 58 5 4

102 60 5 4

103 62 5 5

104 61 5 5

105 59 4 4

106 58 5 5

107 60 4 4

108 57 5 5

109 54 4 4

110 55 5 4

111 56 5 4

112 56 5 NA

113 60 5 5

114 54 6 NA

115 56 5 5

116 54 3 4b

117 57 3 4b

118 58 6 5

119 60 NA NA

120 64 6 7(6)

__________________

a

NA = not aged.

b

Disagreements which were related to NEFSC practice of counting scale edge.

___________________________________________________________________________________________
Page 7

Table 3. List of participants at the Summer Flounder Aging Workshop, held 1-2 February 1999 in

Woods Hole, Massachusetts

_________________________________________________________________________

Name Affiliation

_________________________________________________________________________

Randy Gregory North Carolina Division of Marine Fisheries

Rick Monaghan North Carolina Division of Marine Fisheries

Steve Bobko Old Dominion University

Steve Wischniowski Old Dominion University

Frank Almeida Northeast Fisheries Science Center - Woods Hole Laboratory

George Bolz Northeast Fisheries Science Center - Woods Hole Laboratory

Jay Burnett Northeast Fisheries Science Center - Woods Hole Laboratory

Blanche Jackson Northeast Fisheries Science Center - Woods Hole Laboratory

Kathy Lang Northeast Fisheries Science Center - Woods Hole Laboratory

Nina Shepherd Northeast Fisheries Science Center - Woods Hole Laboratory

Mark Terceiro Northeast Fisheries Science Center - Woods Hole Laboratory

_________________________________________________________________________
Page 8

Table 4. Details of the 50-fish NEFSC summer flounder scale sample exchange with the NCDMF, including

fish size, month of capture, source of specimens, geographic area of collection, original and adjusted

(in parentheses) age determinations, and workshop resolution of, and/or reason for, disagreement

between agencies.

___________________________________________________________________________________

 Total

 Length Age Determinationc

 Workshop

 ID (cm) Month Sourcea Areab NEFSC NCDMF Resolutiond

___________________________________________________________________________________

1 24 Sep Survey VA 0 0

2 32 Sep Survey VA 1 1

3 40 Sep Survey DEL 1(2) 2

4 59 Sep Survey SNE 3 3

5 49 Sep Survey NYB 2 2

6 34 May MDMF SNE 2 1 2; count edge

7 45 May MDMF SNE 2 1 2; count edge

8 30 May MDMF SNE 1 1,0 1; count edge

9 53 May MDMF SNE 3(4) 4

10 56 May MDMF SNE 3 2 3; count edge

11 45 Feb Survey GB 3 3

12 37 Feb Survey GB 2 2

13 58 Feb Survey GB 4 4

14 28 Feb Survey HAT 1 1

15 36 Feb Survey HAT 2 1 2; count edge

16 40 Mar Survey DEL 2 2

17 32 Mar Survey DEL 1 2 Disagree-A

18 49 Mar Survey SNE 3 2,3 3; count edge

19 19 Mar Survey VA 1 0 1; count edge

20 37 Mar Survey HUD 2 2

21 30 Feb Survey DEL 1 1

22 36 Feb Survey DEL 3(2) 2 Omitted

23 48 Feb Survey VA 3 3

24 41 Feb Survey SNE 2 3 3; A

25 54 Feb Survey GB 2 2

26 36 Jan Fishery HUD 2 2

27 44 Jan Fishery HUD 2 3 Disagree-A

28 56 Jan Fishery DEL 3 4 Disagree-B

29 51 Jan Fishery DEL 3 4 Disagree-A

30 64 Feb Fishery VA 4 5(4)

31 41 Feb Fishery VA 2 3 Disagree-A

32 53 Feb Fishery VA 3 5 Disagree-B

33 32 Feb Fishery VA 1 1

34 33 May Fishery NJ 1 1

35 36 May Fishery NJ 2 1 2; count edge

36 43 May Fishery NJ 2 2

37 56 Jun Fishery SNE 3 3

38 50 Jun Fishery SNE 2 3 Disagree-A

39 38 Jun Fishery SNE 2 1 2; count edge

40 32 Aug Fishery DEL 0 1 1; A

41 33 Aug Fishery DEL 1 1
Page 9

Table 4. (Cont.)

___________________________________________________________________________________

 Total

 Length Age Determinationc Workshop

 ID (cm) Month Sourcea Areab NEFSC NCDMF Resolutiond

___________________________________________________________________________________

42 28 Jul Fishery DEL 0 NAe

43 40 Sep Fishery DEL 1 1

44 34 Sep Fishery DEL 1 1

45 42 Oct Fishery VA 1 1

46 33 Oct Fishery VA 1 1

47 54 Oct Fishery VA 2(3) 3

48 74 Sep Fishery DEL 5 5

49 68 Sep Fishery DEL 4 5(4)

50 52 Dec Fishery DEL 2 2

___________________

a

Survey = NEFSC winter, spring, or autumn bottom trawl survey; MDMF = MDMF inshore bottom trawl survey;

and Fishery = U.S. commercial landings.

b

GB = Georges Bank; SNE = Southern New England; HUD = Hudson Canyon; NYB = New York Bight; NJ = New

Jersey; DEL = Delaware Bay; VA = Virginia; and HAT = Cape Hatteras.

c

Adjusted ages were obtained during the exercise to determine precision levels. Two ages listed for the NCDMF

indicate differences between age readers.

d

Disagreement reasons: A = choice of first annulus; B = choice of a scale event as a check as opposed to an

annulus.

e

Not aged.

___________________________________________________________________________________
Page 10

Table 5. Number of fish assigned by the NEFSC and NCDMF to various

age classes based on the 1999 workshop re-aging by each agency

of the 50-fish sample of summer flounder scales. (Number of assignments in agreement are in bold underlined numerals.)

__________________________________________________________

 NCDMF Age NEFSC Age Determinations

Determinations 012345

__________________________________________________________

0 1

1 13

2 1 14

3 3 8

4 3 3

5 12 1

______________

Number of fish: 50

Number aged by readers from both agencies: 48

Number of agreements: 40 (83%)

Number of disagreements: 8 (17%)

__________________________________________________________
Page 11

Figure 1. Scale image (magnification 20X) from a 34-cm male summer flounder captured in May 1995 during the MDMF spring inshore bottom

trawl survey, which was aged by the NEFSC as age 2 and by the NCDMF as age 1 in the original 50-fish NEFSC exchange sample. The

first annulus is indicated. Workshop participants agreed on age 2.
Page 12

Figure 2. Scale image (magnification 12.5X) from a 33-cm summer flounder collected on 4 March 1997 during the North Carolina winter

commercial fishery, which was aged by the NCDMF as age 1 and by the NEFSC as age 2 in the 120-fish NCDMF exchange sample. The

first annulus is indicated. Workshop participants agreed on age 1.
Page 13

Figure 3. Statistical areas used by the NEFSC for recording the locations of harvests of marine fisheries resources off the northeastern United

States.
Page 14

Figure 4. Scale image (magnification 20X) from a 33-cm male summer flounder captured in March 1996 during the NEFSC spring bottom trawl

survey, which was aged by the NEFSC as age 1 and by the NCDMF as age 2 in the original 50-fish NEFSC exchange sample. Both

NCDMF annuli are indicated; NEFSC considers the first mark to be an early life history event. Workshop participants did not resolve

the disagreement.
Page 15

Figure 5. Scale image (magnification 12.5X) from a 50-cm fish collected in June 1995 by the NEFSC from the commercial fishery, which was

aged by the NCDMF as age 3 and by the NEFSC as age 2. The first two NCDMF annuli are indicated; NEFSC considers the first mark

to be an early life history event. Workshop participants did not resolve the disagreement.