Biology of the Striped Cusk-Eel, Ophidion Marginatum, from North Carolina

BULLETIN OF MARINE SCIENCE, 61(2): 327–342, 1997

BIOLOGY OF THE STRIPED CUSK-EEL, OPHIDION MARGINATUM, FROM NORTH CAROLINA

Frank J. Schwartz

ABSTRACT Nearly 2500 striped cusk-eels, Ophidion marginatum, were collected during a 6-yr intensive, 22-station trawl sampling of the Cape Fear River and nearby Sound and Atlan- tic Ocean areas in 1973-1978. Problems existed in confirming the specimens were O. marginatum rather than the similar appearing and ranging crested cusk-eel, O. welshi. The taxonomy remains unresolved but radiographs confirmed the North Carolina specimens were O. marginatum. Catch/effort and repetitive yearly sampling was compared by month, capture by size and station, morphometric relationships, age and growth, crest development, and food analyses. The study revealed O. marginatum was more active than previously believed, males and some females developed head crests, females were larger than males in size and many body-organ relationships, and females attain age 4 while males live for 3 yrs. O. marginatum feeds on a variety of foods, primarily crustaceans and fishes. Much remains to be learned of this elusive and systematically confus- ing species.

Cohen and Nielsen (1978) reviewed the taxonomy of the Ophidiiform fishes, a group that includes the subfamily Ophidiinae (Pisces: Ophidiidae) which are mostly shelf- water inhabiting species (Gordon et al., 1984; Nelson, 1994). At least two similar and perhaps conspecific species pairs of cusk-eels, genus Ophidion, occur in the western Atlantic Ocean (Lea, 1980). One pair includes Ophidion (= Rissola) marginatum (DeKay, 1842) (striped cusk-eel) and O. welshi (Nichols and Breder, 1922) (crested cusk-eel). O. marginatum ranges from New York to northeastern Florida, O. welshi, from Georgia to northwestern Florida and the northern Gulf of Mexico (Fahay, 1992; Robins and Ray, 1986). Larvae and transformed specimens of O. welshi are now known from at least New Jersey southward (Fahay, pers. comm.). O. marginatum and O. welshi are similar in appearance, but their taxonomy is far from resolved. Both species possess horizontal stripes on the body and adult males are known to develop crests. Although Fahay (1992), Gordon et al. (1984), and Miller and Jorgensen (1973) presented meristic data that was intended to separate the two species, broad over- laps exist in meristic counts. Clearly the taxonomic relationships of the two species is not resolved. Little or no detailed information pertains to life history aspects of either species, other than size and sexual dimorphism (Robins, 1960) and nocturnal and burrowing behavior (Greenfield, 1968; Herrera et al., 1985; Hoese and Moore, 1977; Retzer 1991; Robins and Böhlke, 1959). Retzer (1991) examined life history aspects of 390 O. welshi from off Texas, and Courtenay (1971) and Rose (1981) noted crest development in O. marginatum from the western Atlantic. Capture of 2420 O. marginatum from 1973-1978 in the Cape Fear River North Caro- lina permitted studies of sizes, crest development by sex, morphometric and body organ relationships, length-weight relationships, catch effort, ages, and food habits.

327 328 BULLETIN OF MARINE SCIENCE, 61(2): 327–342, 1997

METHODS

From 1973 to 1978, a 22-station survey was made of a 7854 ha area, that included the Cape Fear River and nearby areas, Masonboro Sound, the river from buoy 42 near Wilmington, North Caro- lina, southward for 17 km to and including the adjacent Atlantic Ocean (Fig. 1). Sampling was done with 7.6 and 12.2 m semi-balloon otter trawls and consisted of 3196 small (38.6%) and 5088 large otter trawl tows (61.4%). Sampling occurred during 0.25 h daylight tows. Time and direction of sampling usually was influenced by prevailing water currents, numerous hangs, and commercial ship traffic. Sampling occurred twice each January, weekly from February through May and Sep- tember through November, and half of December. June, July, and August of each year were sampled monthly. See Schwartz et al. (1982) for additional descriptions of each station’s substrates, physi- cal, and chemical features. Species determinations were made by examining and comparing radiographs produced by a Picker Hot-shot X-ray unit of O. marginatum from North Carolina and O. welshi (UF O37996) from the Gulf of Mexico: Fifty-eight percent of the specimens captured (1403) were measured and examined in detail for sex, age and growth, body-organ and morphometric relationships, and food analyses, 210 (8.7%) were measured but not worked up or sexed, and no lengths were taken of 807 (33.3%) specimens (Table 1). Several lots of the 1973 specimens were deposited in the IMS-UNC fish collection at Morehead City, North Carolina. Largest catches occurred in 1974 (1088 specimens) and 1978 (589). All O. marginatum were immediately preserved in the field in 10% formalin. Laboratory analyses consisted of measuring head (HL), eye (E), standard (SL), and total (TL) lengths in millimeters (mm). Total body (BW), liver, and intestines were weighed to the nearest 0.01 g. Eye, heart, gonads, kidneys, and spleen weights were expressed in milligrams. Several body relationships were examined for each sex: SL/TL, HL/SL, E/SL, E/HL, SL/BW, TL/BW, and E/BW. Morphometric and body-organ weight relationships were determined by the formula log y = a + b log x. Ages were determined by noting evident annuli on each vertebra. Measurements from the focus to each annulus and the outer edge of each vertebra permitted back calculations of length at each age using the formula log y = a + b log x. Stomach and intestine food contents were examined in 549 males and 854 females. Each food eaten was determined as percent fullness, percent volume, and percent frequency of number. Each food item was determined to the lowest possible taxon and an index of relative importance (IRI, Pinkas et al., 1971) was calculated where IRI = (%N + %V) . %F, N = numerical percentage, V = volumetric percentage, and F = frequency of occurrence percentage, as a means of ranking the percent each food was found in either the stomach or intestine. Head crest formation was determined by external and internal visual examination of each speci- men, as external examinations alone were often misleading. Crests, depending on sex and time of year captured, were often not visible on males or females. Gonads were examined and verified the sex of each individual.

OBSERVATIONS

Combining ranges given by Fahay (1992), Gordon et al. (1984), and Miller and Jorgensen (1973), O. marginatum has 52-55 caudal vertebrae (vs. 50-52 in O. welshi), 138-162 dorsal rays (vs. 128-150) and 116-131 anal rays (vs. 105-122). North Carolina specimens possess 15 precaudal, 53-54 caudal vertebrae (total 68-69), 149-155 dorsal, and 118-124 anal rays indicating the study specimens were O. marginatum. CATCH/EFFORT. — Over 2 million fishes were collected during the 6-yr sampling period (Schwartz et al., 1982) of which 2420 were O. marginatum. Two hundred thirty-five of the 2420 O. marginatum were captured during the 6-yr sampling efforts in small trawls SCHWARTZ: BIOLOGY OF THE STRIPED CUSK-EEL 329

Figure 1. Location of river-channel and shoal otter trawl stations ( ■ ) sampled in the Cape Fear River and adjacent waters between 1973 and 1978. Buoys ( ● ), CS = CPL intake Canal Screen Station. 330 BULLETIN OF MARINE SCIENCE, 61(2): 327–342, 1997

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laohSdnalennahC raeY S3noitat 149715971697179718971l97Tota 433732E 1 4112 46172W C246BIN C4BIS3222331317 121274 31283 227 1421 233E 14252513 213 132533532001 29W3 383963187 C8S 985815641611 C1B2 3610 C2B1 158 C2M8111 179E1413111174 189 11081116247 18W9 12545263 12E8 8125121301 188 1071814856 198W 124117 O5C1,23644312723742 T0lato 281180820152569850242 Mderusae— 04001625057211131%4058.0 wdekroup Measured— 93923 7033012%7.8 notworkeduporsexed N7el.onshtg 111834388354478%033.3 Eot-troffws S3martllawl 304417459766674156319 L1egraartwl 51761919500151506884508 Cnahlenoitatssn=42,22,71,31,98 Shlaooitatssn=424,E2WC,BINC,B1,SI72,432,E3W1,91,E9W1,81,E8W Powre-tnalpClanaoitatssn=C,SCB,2CB,ICM 0=O,naecCS=ClanaSsneerc while 2185 were collected by large trawls. Largest, combined sampling efforts occurred in 1975-1977, with 1662, 1684, and 1681 tows made each year respectively (Table 1). SIZE/YEAR. —Overall, captured O. marginatum ranged from 41-245 mm TL (Table 2, Fig. 2). Mean sizes for the 1403 specimens measured and examined in detail (Table 2), regardless of sex, ranged 132.8 (in 1977) to 161.1 mm TL (1978). Smallest specimens were collected in 1976 and 1977 while the largest individuals occurred in 1974 (Table 2). SCHWARTZ: BIOLOGY OF THE STRIPED CUSK-EEL 331

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NUMBER/MONTH/YEAR. —Most specimens were captured between March-May or De- cember (1971 specimens) with lesser numbers during other months (Table 3). Mean sizes and ranges (Table 3) varied greatly between month and years captured. May 1975 (48 mm TL) and March 1977 (42 mm TL) produced the smallest specimens captured. Largest individuals were caught May 1974 and 1978 respectively (245 and 230 mm TL) (Table 3). CAPTURE/SIZE/STATION. —The Carolina Power and Light Company intake canal screens station with a newly dug muddy substrate (CS, Fig. 1, Table 3) produced 1161 specimens, 988 of which were captured in 1974. Eighty-three (92-220 mm TL) of the 988 were captured in February 1974, 163 (91-224) in March, 292 (103-210 mm TL) in April, 242 (115-212) in May, 45 (134-217) in June-July, two in October (97-157), and 171 (112-123) in December. Eighty-six of the 988 specimens were not measured. Other stations and substrates where O. marginatum were seasonally abundant were: Atlantic Ocean (427 specimens, sandy-mud), CBI South in Masonboro Sound (173, sand), 18E in the lower river (103, sand), 23W (78, sandy-mud), channel station 19 (74, mud), and channel station 18 (65, sandy-mud) (Table 1, Fig. 1).

Figure 2. Standard length (SL) mm frequencies of 548 ( ■ ) male and 855 ( ❑ ) female cusk-eels, collected 1974-1978, all years and stations combined. 332 BULLETIN OF MARINE SCIENCE, 61(2): 327–342, 1997

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)899=N(4791 )442=N(5791 MNXehtno rhangMNXeont rang F3891742.9M0-19 23 81950.124-13 M31461044.8A9-22 50 61156.96-22 A22591647.1M701-20 1021328.48-21 M22641556.1N03-24J4281025.108-22 J5N401767.1L24-21J561734.64-16 O201727.9S7-15 101059.159. D11671350.1O09-21 331279.167-19 1976(N=66) 1977(N=24) F901029.5F5-21 10588.5 M3381056.5M7-20 63616.42-20 A101063.1A63. 4986. 058-11 M5141443.6M9-20 301321.78-20 J20N 1950.1N41-15J561978.169-18 A251973.1A68-17 101393.19 S251487.1O81-19 201974.169-17 N25489.4N1-5 21253. 5105-20 1978(N=71) F351008.67-15 M921301.56-9 A481777.155-19 M6331078.58-23 J58N 1452.103-18 J20L 1846.134-15 A2191661.71-16

MEASUREMENTS AND PROPORTION. —Combined male standard lengths (SL) (548 specimens) ranged from 41 to 210 mm ( x 143.3), while 855 females ranged from 41 to 245 mm ( x 148.6) (Fig. 2). Male head lengths (HL) (548 specimens) ranged from 8 to 42 mm ( x 27.9), females (855) from 8 to 47 mm ( x 30.4) (Fig. 3). Male eye lengths (548 specimens) ranged from 1 to 9 mm ( x 6.1), 855 females from 1 to 10 mm ( x 6.2) (Fig. 4). In terms of HL/TL ratios, male ratios were x = 5.4, females x = 5.0, E/TL male ratios were x = 4.4, females x = 4.5. Regression of SL/TL, SL/HL, SL/eye, HL/eye relationships of 1403 specimens, combined, or 548 males and 854 females separately, Table 4, suggested the best correlations were for SL/TL and SL/HL (Table 4), with r usually 0.932 or better. Length-weight regressions and relationships indicated females were both smallest and largest at each age except age 1 (Table 4). AGE AND GROWTH. —Examining vertebra and back calculating lengths at each annulus indicated the largest males at 196 mm TL were 3 yrs old and largest females at age 4 were 204 mm (Table 5). BODY-ORGAN WEIGHT RELATIONSHIPS. —Regressions of liver, eye, heart, intestines, gonads, kidneys, and spleen weights against body weight yielded the following results (Table 4): female livers were always heavier than males at all sizes; female eyes were much larger than male eyes, although regression for both sexes indicated eye size was smaller SCHWARTZ: BIOLOGY OF THE STRIPED CUSK-EEL 333

Figure 3. Head length (HL) frequencies (mm) for 548 ( ■ ) male and 855 ( ❑ ) female striped-cusk eels captured 1973-1978, years and stations combined.

as body weight increased; heart weights were virtually alike for both sexes at all sizes and body weights; male intestine weights were consistently heavier than female intestines at all sizes; female gonad weights were heavier except for males smaller than 210 mm TL; female kidney weights were consistently heavier than male kidney weights, especially at smaller body weights; female spleen weights were greater than male spleens at all body weights. CREST DEVELOPMENT. —Externally, most of the 1403 species examined in detail ap- peared to be females. Only 88 of 549 males (115-210 mm TL, x = 148.7, 118 mm TL smallest with crest) exhibited a slight head crest and 92 (120-190 mm TL x = 149.9) exhibited a strong head crest, especially in November and December caught specimens (180-210 mm TL). However, all internal examinations of air bladders and vertebral col- umns found that 12 females (155-220 mm TL, x = 189.6) also had developed crests (Fig. 5). FOOD ANALYSIS.—Foods were found in 132 of 549 males and 204 of 854 females, 58.9% of the 1403 examined. One hundred male and 134 female stomachs (41.1%) were empty. Thus, recognizable food was found 25% of the time in stomachs, 61.4% in intestines as chyme, and 13.6% of the time in both the stomach and intestine. Nematodes, crustaceans, fishes, and debris were the prevailing foods, with crustaceans the dominant food by volume, number, and frequency of occurrence (Table 6, Figs. 6a, 6b).

DISCUSSION AND CONCLUSIONS

Analysis of variance tests of North Carolina O. marginatum by year and month of capture were highly significantly different (Table 7). This was caused by more and larger specimens being captured in 1974 and 1976 than in 1975, 1977, or 1978 (Table 3). Ver- tebral and dorsal fin ray counts, from radiographs, of selected specimens from through- 334 BULLETIN OF MARINE SCIENCE, 61(2): 327–342, 1997

Figure 4. Eye diameter (mm) frequencies of 548 ( ■ ) male and 855 ( ❑ ) female striped cusk-eels collected 1973-1978, years and stations combined.

out the study sites fell within ranges noted for O. marginatum (Fahay, 1992; Gordon et al., 1984; Miller and Jorgenson, 1973). Robins (1960) commented that female Ophidion were larger than males and reached 250 mm TL (Robins and Ray, 1986), a condition found herein. Greenfield (1968), Robins and Böhlke (1959), and Smith (1907) noted primarily nocturnal burrowing habits of Ophidion spp., especially O. marginatum. Retzer (1991) noted 21% of his O. welshi specimens were captured during daylight hours. Be- cause this study’s 2420 specimens of O. marginatum were collected during daylight trawl tows, O. marginatum may be far more active during the day than primarily believed. However, daylight capture activity may be masked by the fact that the Cape Fear River and nearby area waters were chocolate-brown colored at all times by tannins, thereby visibility was nearly zero, permitting less light penetration and perhaps more cusk-eel daytime activity. Smith (1907) noted that North Carolina O. marginatum head length - total length ratios were 5.3. Nichols and Breder (1922) noted head and eye in total length ratios of 5.2 SCHWARTZ: BIOLOGY OF THE STRIPED CUSK-EEL 335 .thgiewydoB=WB,retemaideyE=DE,htgneldaeH=LH,htgnellatoT=LT,htgneldradnatS=LS.sretawtnecajdadnareviRraeFepaCni8791-4791 detcelloc)groLTmm(spihsnoitalernagro-ydobdnacirtemohpromelamefdnaelam,denibmoc, 9 3 6 9 9 4 1 3 0 1 8 6 8 4 9 9 8 8 8 8 9 8 4 5 8 9 8 9 ...... 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 8 8 0 9 6 8 9 5 0 8 6 8 0 9 8 8 7 5 9 8 8 8 9 2 2 2 ...... 19 02 03 05 04 12 04 06 09 08 00 01 06 03 l a m e F 6 7 5 0 7 4 1 4 0 4 4 7 2 9 0 7 3 7 1 9 9 0 4 6 4 5 1 1 ...... 09 17 30 10 23 4 05 3 11 11 0 24 10 46 -8 -5 -9 5 5 5 5 5 5 5 5 4 5 4 5 5 5 88 83 32 38 37 32 35 35 34 38 37 80 86 83 9 5 8 0 7 1 8 4 9 2 5 5 8 7 9 9 8 9 8 7 8 7 6 9 8 9 8 9 ...... 04 05 04 04 04 03 03 04 03 03 05 05 05 05 0 1 1 6 7 2 4 7 0 3 3 9 9 9 0 9 8 8 7 2 9 8 2 9 9 2 2 2 ...... 19 07 08 07 08 18 09 09 19 08 04 00 05 04 l a Me 2 1 6 2 5 4 0 5 3 4 5 2 6 7 0 9 4 7 0 0 0 1 6 5 4 5 0 1 ...... 0 16 30 14 26 5 18 3 1 10 0 28 12 43 -0 -0 -3 -1 -6 4 4 4 4 4 4 4 3 3 4 3 4 4 4 53 56 25 28 29 20 27 27 22 29 24 53 54 55 9 3 6 9 8 1 1 2 1 8 7 5 8 5 9 9 8 8 8 8 9 8 5 5 8 9 8 9 mutanigram.O ...... 08 08 00 00 00 00 00 09 04 00 07 08 08 08 sexeSdenibmo 0 4 6 8 0 1 5 0 9 5 0 2 7 8 0 9 8 8 7 2 9 9 3 8 9 2 2 2 ...... 19 08 08 07 07 10 00 01 11 06 05 08 04 01 rofsalumrofnoissergergoL.4elbaT 5 1 8 1 9 9 6 6 6 9 0 5 1 8 0 8 3 7 1 9 9 1 9 6 4 5 1 1 ...... Ce 0 15 30 11 29 4 03 3 0 12 0 28 10 48 -7 -0 -6 -0 -5 0 0 0 0 9 9 9 9 2 9 8 0 0 0 Na b r Na b r Na b r 4 4 4 4 53 54 57 56 54 52 56 4 4 4 16 16 13 10 16 13 19 e s s n y n i d e t t D D r e a r D s n D e e n a e e e l d v e t e o i L e y i y p L y n L L y E L H S G K H E S I E ------T-L H E - - - L W W W W W W W W W W L L S2 S3 S3 H3 B4 B3 B3 B7 B3 B2 B3 B3 B3 B3 336 BULLETIN OF MARINE SCIENCE, 61(2): 327–342, 1997

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M))mmLS(sela Females(SLmm AegeAg ANge123N1234 158031012417 251634145147351671 3515732161893051771502 41195311681420 T5/latomeanelnhtg24331551613926481671502420 I1nercmetngrowht(mm) 2140392-- 7168.0=r,xgol9707.0+1917.0=ygolselaM 7028.0=r,xgol9357.0+7806.0=ygolselameF and 5.1, respectively. Cape Fear specimens possessed HL/TL ratios of 5.35 for males and 4.97 for females while eye in total length ratios were 4.37 (males) and 4.46 (females) respectively. Rose (1968) characterized musculature, swim bladder, and bones of O. holbrooki were involved with crest or sound production. Courtenay (1971) commented on crest development of O. marginatum, although males of both O. marginatum and O. welshi (Robins and Ray, 1986) were known to develop crests. Courtenay (1971) also stated that only males possessed muscles that permitted crest development. This study has shown that males and some females (12) do develop head crests especially in November and Decem- ber. Whether the latter were biologically true females was not resolved, even though their gonads exhibited “normal” female features. Retzer (1991) noted the youngest mature

Figure 5. Mean and length frequencies of 88 of 549 male striped cusk eels exhibiting slight head crests ( ❑ ), 92 with strong crests ( ■ ), and 12 of 854 females with crests (cross-hatched bars) collected 1973-1978 in Cape Fear River and adjacent waters. SCHWARTZ: BIOLOGY OF THE STRIPED CUSK-EEL 337 Figure 6a. IRI depictions by percent volume, number and frequency of occurence of various foods found in striped cusk-eels captured in the Cape Fear River and River in the Cape Fear foods found in striped cusk-eels captured of occurence various number and frequency percent volume, 6a. IRI depictions by Figure All years Annelida, N = Nematode, D = Debris. tract combined. C = Crustacea, P = fishes,A = and areas of the digestive All stations, years, adjacent waters. and stations combined. 338 BULLETIN OF MARINE SCIENCE, 61(2): 327–342, 1997

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Fh/metidoo MalestomacMaleintestine c.ategoryV.oolN.qF.erV.oolN.Freq N0ematoda 000..00005.0054..0030.4 A6nnelida 163..20606.8063..3021.7 N3ereids 090..90304.4013..3001.5 H3irudenia 072..30302.4040..0010.2 C9rustacea105.7147.0100.9162..0163.8 C3opepods 090..2030.4 Squllia A9mphipods342.3.700.3 44.085.001.5 I9sopods 167..8031.9 M7yisds 338.1.81527.1072..3091.2 P5enaeids 436..00011.5040..0040.0 Alpheus P3alaemonidae040..2010.2 Potrunidae X5anthidae 113..30919.2063..1080.1 U7nknownsp.090..3030.4 P8sices 480..7114.5 Anchovy S4cup 090..1030.4 C6roaker 113..2091.2 S7pot 090..3030.4 Cynoscions7p.040..4010.2 G3oby 122..6071.0 G.hatsatus 040..47010.2 P.irtbulus 040..19010.2 Parailchthyss3p.081..2030.4 S.plagiusa Unknownsp. Vetrebra S2cales 040..00102.2 1.8 D3ebris094..60210.7296..6326.2 D4igested 063..10710.0267..6526.2 V9egetation031..4040.6 Clamshell Eggs Uniddebsir T6otal 242.4138.9118.0467..05312.2 SCHWARTZ: BIOLOGY OF THE STRIPED CUSK-EEL 339

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090..75030.4 04.0201.00.2 040..190105.209.003.00.4 595.19517.8313.9118.4147.4305.81000.01000.0100.0 340 BULLETIN OF MARINE SCIENCE, 61(2): 327–342, 1997 6b. Percent volume, number, and frequency of occurrence of various foods found in male and female cusk-eel stomachs or intestines. All years and stations All years of occurrence foods found in male and female cusk-eel stomachs or intestines. and frequency of various number, volume, Percent 6b. combined. SCHWARTZ: BIOLOGY OF THE STRIPED CUSK-EEL 341

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SmnoitairaVfoecruo DsegreesofFreedoNeameofSpecieMeanSquar Y4ears 2*77.169.3* M0onth 151*43.14.5* Y4ear&MonthInteraction10138.1. W5ithinsubclasses 75117896.2. T3otal 7142335. females were 125 mm TL and the smallest female O. welshi specimens in October and November, 160 mm TL. O. marginatum from the Cape Fear River seemed to also spawn in November and December, with the smallest mature females (160 mm TL) being caught in December, yet some (151 mm TL) female ovaries were full of eggs in February. Ova- ries were flaccid in March yet often enlarged in May specimens. Robins (1960) noted crustaceans and small fishes were foods of Ophidion. Greenfield (1968) noted nine types of foods in O. scrippsi. O. marginatum from the Cape Fear system also fed on similar yet many more food items. Even though it was impossible to validate that rings observed on O. marginatum vertebrae were formed annually, as preferred by some (Francis 1990), females grew larger and older than males (Table 5), and/or similar sized O. welshi(Retzer, 1991). Retzer (1991) also indicated possible length frequency age groups for O. welshi, although no clear cut similarity existed for O. marginatum of the Cape Fear River (Table 5). This study has revealed many aspects of the biology of O. marginatum. Captures indicated that it is a much more active species than expected. Similarly, constant sampling of the study area or power plant intake screen stations did not seem to affect capture or population size. While usually considered an insignificant member of a local fish fauna, O. marginatum presence and activities should no longer be ignored or left unstudied.

ACKNOWLEDGMENTS

Thanks are extended the many technicians (52) that assisted during the 6-yr Cape Fear River studies. M. Fahay, National Marine Fisheries Service, Sandy Hook, New Jersey, reviewed the manuscript, commented on identification and northern distribution of O. welshi; W. Courtenay, Florida Atlantic University, Boca Raton, Florida reviewed the manuscript and commented on crest production in Ophidion; and C. Gilbert, Florida State Museum, Gainesville, Florida, provided taxonomic and other comments on the manuscript and loaned O. welshi from the Gulf of Mexico for radiograph comparisons. M. Shelgren, Slippery Rock College, Slippery Rock, Pennsylvania, assisted with the body-organ analyses. R. Barnes, IMS, produced the figures. L. White, IMS, typed the text.

LITERATURE CITED

Cohen, D. M. and J. G. Nielsen. 1978. Guide to the identification of the fish order Ophidiiformes, with a tentative classification of the order. NOAA Tech. Rep. NMFS Circ. 417. 72. p. Courtenay, W. R. 1971. Sexual dimorphism of the sonic producing mechanisms of the striped cusk-eel, Rissola marginata (Pisces: Ophidiidae). Copeia 1971: 259-268. 342 BULLETIN OF MARINE SCIENCE, 61(2): 327–342, 1997

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DATE ACCEPTED: May 23, 1995

ADDRESS: Institute of Marine Sciences, University of North Carolina, Morehead City, North Carolina 28557 .