BULLETIN OF MARINE SCIENCE, 29(1): 1-18, 1979

EARLY LIFE-HISTORY OF THE EDWARDSI (PISCES, ) IN THE WESTERN NORTH ATLANTIC

P. H. J. Castle

ABSTRACT

The eel Morillgua edwardsi (Jordan and Bollman, 1889) is known principally from immature specimens in the western North Atlantic from southwards to Atlantic Panama and Colombia. Its distinctive larva, earlier recognized as diptychus Eigenmann, 1900, has about seven alternating, midlateral melanophores and also one in front of the anus. Larvae have 110-124 myomeres, hatch at about 5 mm TL and reach full growth at 50 mm TL, a process which takes 3-5 months, before metamorphosis begins. They live in the upper 35 ill and occur over a broad area of the western North Atlantic encompassing 1O°-40oN and 40o_88°W but those of about 10 mm TL occur only near the Caribbean Islands. Spawning is suggested to occur in the Caribbean the year round but principally at monthly intervals from November to April. Some larvae are dispersed out into the Atlantic by the Gulf Stream. This pattern of distribution and dispersal is similar to that of the only other Atlantic moringuid Neoconger mucronatus Girard, 1859.

At a time when the classification of the 1968) to clarify the nomenclature of the is undergoing critical scrutiny, major Moringuidae pointed out that at least one difficulties are still being presented by the character (number of vertebrae) would family Moringuidae. Moringuid eels are need to be considered in any re-appraisal readily captured with piscicides in many of moringuid classification. However, it be- shallow areas of the tropical Indo-Pacific came clear from the previous study that and western Atlantic Oceans and are con- vertebral numbers were, alone, insufficient sequently abundant in museum collections to distinguish the species. around the world. However, it is still not While it is now reasonably certain that possible confidently to identify the Indo- the Moringuidae contains but two genera: Pacific species. Furthermore, little is known Moringua Gray, 1831 and Neoconger about the life-history and biology of these Girard, 1858 (Smith and Castle, 1972) eels, including the complex changes which this was not always considered to be so. they appear to undergo prior to maturation Species of Moringua have at times been (Gosline and Strasburg, 1956). described in six families, the Ratabouridae, The most substantial key to members of Ptyobranchidae, Moringuidae, Stilbiscidae, the family, based essentially on body pro- Echelidae, and Anguillichthyidae and under portions and other external characters ten other generic names: Rataboura Gray, (Schultz, et aI., 1953) was seriously ques- 1831, Pterurus Swainson, 1839; Pachyurus, tioned by Gosline and Strasburg (1956) Swainson, 1839; Ptyobranchus McClelland, who demonstrated marked sexual dimorph- 1844; Aphthalmichthys Kaup, 1856; Pseu- ism in Hawaiian moringuids which they domoringua Bleeker, 1865; Stilbiscus Jor- referred to Moringua macrochir Bleeker, dan and Bollman, 1889; Mayerina Silvester, 1855. This observation was foreshadowed 1915; A nguillichthys Mowbray, 1927 and by the brief studies of Parr (1930) and Merinthichthys Howell Rivero, 1935. The Gordon (1954) on Moringua edwardsi distinctions between these nominal genera (Jordan and Bollman, 1889) in the tropical were drawn essentially on the basis of what West Atlantic. My own attempt (Castle, most probably are morphological changes 2 BULLET]N OF MARINE SCIENCE, VOL. 21, NO. ], ]979 during maturation of males and females, i.e., distinctive for them to have been readily those shown for Hawaiian moringuids and separated 'rom leptocephali of Neoconger known also to occur in other species. These mucronatu;', the only other moringuid spe- changes are indeed as marked as any seen cies in the western North Atlantic. More- in fishes as a group and are certainly more over, the .arvae of M. edwardsi are very than occur in any other genus of eels. It is well represented in the DANA Oceano- now widely accepted that immature morin- graphical Collections as some 1200 speci- guids pass through an "Aphthalmichthys" mens frorr. various Danish expeditions in phase with reduced eyes and fins and that the Atlantc, but mainly from the DANA the "Stilbiscus-Anguillichthys" form with cruises 1920-22. The material included larger eyes and fins is not adopted until specimens of 7.5 mm to 49 mm total maturity of both males and females. How- lengths, as well as metamorphic larvae. From ever, the precise relationship between stage such a L1rge number, wide size and of gonad development, as established geographic 11 range, it is now possible to histologically, and body form has yet to be describe tl e larval life of M. edwardsi as fully studied and described. has already been done for Neoconger It has recently been shown (Castle and mucronatu.: in the western Atlantic (Smith Bohlke, 1976) that the very considerable and Castlt:, 1972) and also to compare variation in body form and particularly these two moringuid species. body size attained at maturity in M. A furth~r 280 moringuid larvae were edwardsi is correlated with sex: mature also collected by the DANA in the Indo- males are only 115-155 mm in length while Pacific OCf an during the Round-the-World females with clearly recognizable ova attain Expedition 1928-30. Some 34 species of 245-360 mm. Furthermore, males have Moringua have been described from this 109-117 vertebrae and females 116-125, ocean (Ca,tle, 1968) but there are almost there being a significant difference in the certainly many fewer valid species. Schultz mean vertebral number in the sexes (112.6 et al. (19.53) recognize 14. My previous and 119.4 in males and females respec- review (Clstle, 1968) suggests that there tively). This discovery at last resolves the are probably about 10 species with a major long-standing problem of the wide variation group ha\ ing vertebral numbers in the in morphology of M. edwardsi and also range 105-130, but with others at about anticipates similar findings in the Indo- 150 and 160. The Indo-Pacific larvae Pacific complex of species. collected JY the DANA have myomeres The present contribution to knowledge ranging fom 98-180 with most between of these eels does not seek to describe or 105-130 arid other groupings at 150, 160, explain these changes in body form, nor and 170. The larval counts therefore to determine the significance of this poly- broadly conform with vertebral numbers of morphism in their life. A clarification of adults. However, adults of Indo-Pacific these phenomena and of specific distinctions moringuidE have not been studied on a and nomenclature in the Indo-Pacific spe- comprehensive basis and as yet it is difficult cies must await a comprehensive systematic to assign most of the larvae from this study including a familiarity with morin- ocean to their adult species. guids in the field. The sekction of Moringua edwardsi en- The purpose of this report is simply to ables a stujy to be made of larval variation, described that part of the life-history prior growth, d.spersal, and distribution in a to metamorphosis of the leptocephalus of single mo 'inguid species without encum- the single Atlantic species Moringua ed- brance of the problems of specific distinc- wardsi. This species lends itself well to tion and :lomenclature that would be in- such a study since the larvae are sufficiently volved in H similar study of the Indo-Pacific CASTLE: LIFE-HISTORY OF EEL MOR/NGVA EDWARDSI 3 species. Knowledge of these aspects of lar- moringuid AphthalmichtllYs caribbeus, a name that val biology of a single, well-characterized was to be later overlooked. In the same year Eigenmann (1900) described Leptocephalus dip- species will perhaps serve as a basis for tye/IIIS, a larval form which was not identified dealing with the Indo-Pacific complex in until many years later. Other families, genera, and due course. species were from time to time admitted to this The larval form of M. edwardsi has been group with the description of Mayerina mayeri known for many years but it has only Silvester, A ngllillichtllYs bahamellsis Mowbray (Anguillichthyidae), Moringlla boekei Metzelaar recently been recognized as such (Eldred, and the Stilbiscidae (Parr). 1968; Castle, 1968; 1969). Eigenmann As more information became available on these (1900) described Leptocephalus diptychus forms the taxa were progressively reduced in num- from two western Atlantic specimens but ber. It became generally accepted, though not definitely proven, that there is but the single spe- Castle ( 1965) showed that leptocephali cies present in the western North Atlantic which with the characters of this species were necessarily must take the name Morillglla edwardsi referable to Moringua. Eldred (1968) de- (Jordan and Bollman, 1889). Castle and Bohlke scribed a further four leptocephali. Thus, (1976), in a study of mainly U.S. material, includ- ing several hundred immature and 40 mature speci- M. edwardsi larval has hitherto been re- mens, as well as some of the DANAlarvae described ported from only six specimens and nothing in this report, finally confirmed this suggestion. further has been known of the early life history of this species. Moringua edwardsi (Jordan and Bollman) Figures 1-13 MATERIAL Stilbiscils edwardsi Jordan and Bollman, 1889: The material for this study came from the fol- 549 (original description, holotype USNM lowing sources, with abbreviations used for them 41735, 337 mm, Green Turtle Cay, Bahamas). in the synonymy and the station list appended: Jordan and Davis, 1892: 645 (description). Jor- ZMUC-DANA Oceanographical Collections, Zoo- dan and Evermann, 1896: 363 (description, based logical Museum, University of Copenhagen, Cop- on original). Jordan, Evermann and Clark, 1930: 89 (listed). Parr, 1930: 15 (description, 1 speci- enhagen; UMML-Rosenstiel School of Marine men BOC 2562, Crooked Island, Bahamas). and Atmospheric Science, University of Miami; Gordon, 1954: 11 (7 specimens, AMNH, 137- URI-University of Rhode Island; FSBC- 368 mOl, Bimini, Bahamas). Castle, 1968: fig. Department of Natural Resources Marine Research 3 (body proportions). Castle and Bohlke, 1976: Laboratory Ichthyological Collection; USNM- table 1 (holotype re-examined, 116 vertebrae, United States National Museum of Natural His- female). tory; PU-Princeton University; BOC-Bingham Aplltha[micllthys caribbeus Gill and Smith, Oceanographic Collections; MCZ-Museum of 1900: 974 (original description, holotype USNM Comparative Zoology, Harvard; ZMA-Zoological 4970, 265 mm, San Geronimo, Porto Rico). Museum, University of Amsterdam; AMNH- Evermann and Marsh, 1902: 71 (description). American Museum of Natural History. Nichols, 1929: 191, fig. 16. Jordan, Evermann and Clark, 1930: 89 (listed). Castle, 1968: fig. SYNONYMY AND DESCRIPTION 3 (body proportions). Castle and Bohlke, 1976: table 1 (holotype re-examined, 117 vertebrae, fe- Moringlla edwardsi has a checkered nomen- male). clatural history, the essentials of which are sum- Leptocephalus diptychus Eigenmann, 1900: 401 marised by Gordon (1954) and in the synonymy (preliminary description). Eigenmann and Ken- that follows here. nedy, 1901: 830 (description, figure, holotype The species first appears in the literature under USNM 49754, 51 mOl, southeast of Nantucket; Stilbiscus Jordan and Bollman, 1889, described paratype, USNM 49753, 38 mm, New Provi- from and then placed in the family dence, Bahamas); Eigenmann and Kennedy, Congridae. Jordan and Evermann (1896) included 1902: 84 (description, figure). Fish, 1927: 308 StilbisCIIs in the Muraenesocidae along with Neo- (myomere count) . D' Ancona, 1928: 112 conger and other genera which were subsequently (listed). Fowler, 1944: 436 (listed). Castle, found to belong elsewhere among the families of 1965: 125 (referred to Morillgua); Castle, 1968: eels. 24 (referred to Morillglla edwardsi); Castle, Gill and Smith (1900) prophetically considered 1969: 38 (listed). Eldred, 1968: 1 (description, Stilbiscus to be a synonym of Moringlla and placed figure, referred to M. edwardsi). it in the Moringuidae, without giving reasons. At Mayerilla mayeri Silvester, 1916: 214 (original the same time they described a further Caribbean description, holotype PU 3037, 310 mOl, Guan- 4 BULLETIN OF MARINE SCIENCE, VOL. 29, HO. 1, 1979

Figure 1. Moringua edwardsi, leptocephalus at various stages of growth. a-b: 17 mm total length, DANA Station 1287, haul IV. c-d: 42.5 mOl total length, DANA Station 1269, haul XI. e-f: 44.2 mOl total length, metamorphic, DANA Station 1292, haul VI.

ica Harbour, Porto Rico; paratype PU 3126, 280 Allister, 068: 82 (branchiostegals). Castle, mm, Porto Rico). Nichols, 1929: 190, fig. 14. 1968: fig.: (body proportions) . Jordan, Evermann and Clark, 1930: 81 (listed). Castle, 1968: fig. 3 (body proportions). Castle Merillthichthys sallcllezi Howell Rivero, 1935: and Bohlke, 1976: table 1 (holotype and para- 343 (origiI~al description, figure, holotype MCZ type noted to have been lost, suggested to be 33453, 22B mm, Matanzas, ). females) . Moringlla boekei Metzelaar, 1919: 18 (original Aphthalmichthys mayeri (Silvester). Beebe and description, figure, holotype ZMA 112.739, 133 Tee-Van, 1933: 45, fig. (Bermuda, Porto Rico). mm, Correlis Bay, Cura«ao). Jordan, Ever- Rubinoff and Rubinoff, 1962: 2 (3 specimens, mann and Clark, 1930: 89 (listed). Castle, MCZ 41459-41461, Galeta Point Reef, Pan- 1968: fig. 3 (body proportions). Castle and ama). Bohlke, 1 J76: table 1 (holotype re-examined, 115 verteb rae, male). Anguillichthys bahamensis Mowbray, in Breder, 1927: 10 (original description, holotype BOC Morillgua edwards; (Jordan and Bollman). No. 34, 117 mOl, Green Cay, Bahamas; paratype Bohlke an j Chaplin, 1968: 69 (description, fig- BOC No. 35, 115 mm, Green Cay, Bahamas; ure, general biology). Eldred, 1968: 1 (larva, descriptioll, figures, 4 specimens 12.1 mm-42.4 second para type lost). Castle and Bohlke, 1976: table 1 (holotype and para type re-examined, 112 mm, Florda Strait). Castle, 1968: 24 (discus- and 111 vertebrae, both males). sion); Ca:.tle, 1969: 22 (listed). Herald, 1972: 63 (1 specimen 508 mm). Smith and Tyler, Stilbiscils bahamellsis (Mowbray). Parr, 1930: 1973: 13 :Great Bahama Bank). 15 (description, 4 specimens BOC No. 2560, Cat Moringlla sp. Caldwell, 1963: 4 (Costa Rica). fsland, Bahamas; 1 specimen BOC No. 2478, Rum Cay, Bahamas; I specimen BOC No. 2561, Mater;al EXllnilled.-1198 specimens, 7.5 mm-49 Crooked Island, Bahamas). Trewavas, 1932: (2 mm total lengths, DANA Oceanographical Collec- specimens 123 mm and 136 mm, ). Mc- tions (ZMUC). Comparative data from a further CASTLE: LIFE-HISTORY OF EEL MOR/NGVA EDWARDS/ 5

serial melanophores alternating on the mid- lateral line and by the large dendritic mass of black pigment immediately in front of the 70 anus. (Larvae of Neoconger mucronatus typically have only a postanal lateral melanophore, or none at all, and the in- 60 testinal pigment). Leptocephali of M. ed- wardsi are fully grown at about 50 mm total length. 50 Remarks.- There is a relatively wide range in the number of myomeres in larval M. 40 edwardsi (1] 0-124). This range is bimodal with frequency peaks at 113-114 and 119- 120 myomeres respectively (Fig. 2). The 30 reason for this bimodality was determined by Castle and Bohlke (1976) to be sexual, that is, larvae with 110-116 myomeres are 20 males and those with 116-124 myomeres are females, reflecting identical bimodality in vertebral number of mature males and fe- 10 males, although gonads are not developed in the larvae. Other reasons for this conspicuous bimodality were considered, in particular,

TOTAL MVOMERES that the two groups might represent two Figure 2. Frequency distribution of myomeres in subspecies or that larvae hatched at various leptocephali of 1\1. edwardsi. times during the year might have different numbers resultant from the effects of dif- 186 specimens, 6.0-51.3 mm total lengths, URI fering environmental factors (e.g., tempera- (48), UMML (119), FSBC (19). ture and salinity). For brief collection details see Appendix. Refer- The DANA larvae cannot be divided into ence may be made to station lists of the DANA Col- two subgroups on any characters other than lections for comprehensive station data. the number of myomeres. The number of Description.-Mean value and number of specimens in which other characters (e.g., specimens examined in parentheses. Total positions of gall bladder, last visceral vessel, myomcres 110-124 (116.65, standard devi- and dorsal origin) could be examined was ation = 3.24, 588), preanal myomeres 72- small compared with the number in which 82 (77.21, 98), postanal myomeres 37-44 myomeres were counted. There is a firm (40.02, 98), dorsal rays 115-137 (125.69, trend for these structures to be placed at a 26), anal rays 115-138 (124.73, 26), more posterior segmental level with increas- caudal rays 3-4+ 3 (l 0). Anterior margin ing numbers of total myomeres but not of gall bladder 55-63 (58.71, 21), last relatively so in actual position (Fig. 3). visceral vessel 70-79 (73.38, 21), dorsal External characters of the adults are so origin 79-87 (83.17, 23). variable with degree of maturity that it would The above meristic data, Figure 1 and be extremely difficult to assess differences Eldred's (1968) description serve to distin- in body characters in any subgroups that guish leptocephali of M. edwardsi from all might be present. It is noted that larvae of other Atlantic eel larvae. Larvae of M. low and high myomere numbers occur with edwardsi are readily recognized by their about the same frequency in any collection 6 BULLETIN OF MARINE SCIENCE, VOL. :9, NO. I, 1979

last visceral iessel dorsal origin 121, gall bladder

122 • • • • • • • • V> • UJ 120 0:: • • • • • • UJ::;: • • • II • • • • • 0 >- 118 • • ::;: • • ...J .. 116 • • • >- 0 >- • • • • • • • • 114 • • • • • • • • • • • ·• • 112 • • • • • • • • • 110 55 60 65 70 75 80 85 90

SEGMENTAL POSITION Figure 3. Segmental position of various structures in leptocepha:i of M. edlVardsi. but that samples of immatures have a bias GRCWTH AND METAMORPHOSIS t~ward the group with the higher number The changes occurring during growth of (I.e., females) (Castle and Bohlke, 1976). the larva from about 6 mm to 50 mm are In order to determine whether or not rather silTilar to those of many other there may be any differences in myomere leptocepha:i. The number of teeth on each numbers in larvae hatched at different times ramus of t:1e jaws steadily increases to be- of the year it would be necessary to examine come about 15 (upper jaw) and 9 (lower a sufficient number of very small larvae jaw) dist'ibuted in three groups (an occurring at these times in the same area anterior grasping tooth followed by a series (i.e., that these larvae were derived from of larger keth and then a series of smaller sympatric spawnings). This was not pos- ones). e olfactory organ differentiates SIble from the available material. Howcver, n relatively '~arly and the nostrils become groups of larvae from particular areas distinct at approximately 25 mm body within the Caribbean area and from early length. Dorsal and anal fin rays become December 1921 to April 1922 were selected clearly established early but the full number and their myomere numbers plotted (Fig. is not attai led until a body length of about 4). At 51. Croix in December and again at 35 mm. Tle lateral and intestinal pigment in April samples contained spots are also established at a very early larvae with bimodal myomere numbers stage (10 mm) so that leptocephali of this which matched the frequency distribution species are distinguishable at all sizes. obtained from all larvae combined. Thus There is a relatively small change in the there would appear to be no basis for the position of the anus during larval life. As suggestion that time of season determined myomere number. However, the limited indicated ill Figure 6 the anus lies almost material precludes absolute certainty that subterminally at a total length of about there is no significant difference in the 10 mm bu1 it steadily advance:; to reach a frequency distribution of myomere numbers point three-quarters of the way along the within the range in specimens from different body at full larval growth. During meta- times of the year. morphosis 'here is only a slight further shift The number of dorsal and anal rays are forwards. [n all species of Moringua the positively correlated, as shown in Figure 5. anus lies ""ell behind the midpoint of the CASTLE: LIFE-HISTORY OF EEL MOR/NOVA EDWARDS/ 7

o DANA 51. llB9, 8.1,,19,1,51,Cloix @ DANA 51.1138. 11.].1927, Slrails 01 Florida

115

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120

115

11o''----1~0----,~0---~30---~GO---~50 10 ,0 30 40 50

TOTAL LENGTH IN MM. Figure 4. Number of myomeres in leptocephali of various sizes from four areas in the Caribbean. body in the adult. In M. edwardsi preanal DISTRIBUTION AND DISPERSAL vertebrae number about 78 in a total of As shown in Figure 7 and summarized 110-124, an indication of the posterior in Figure 8, leptocephali of M. edwards; position of the anus. occur over a wide area of the western North

90

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TOTAL. L.ENGTH IN MM DORSAL RAYS Figure 6. Regression of preanal length (as per- Figure 5. Number of dorsal and anal fin rays In centage of total) on body size of leptocephali of 26 leptocephali of M. edwardsi, M, edwardsi. 8 BULLETIN OF MARINE SCIENCE, VOL. 2~. NO. I, 1979

Figure 7. Distribution of leptocephali of M. edll'ardsi in the we~tern North Atlantic. Size ranges indi- cated.

Atlantic, viz., from looN to 40oN, and from larvae (F:mC No. 8361L: 6 mm and 400W to 88°W including therefore the FSBC No. 8362L: 6.9 mm) were collected Caribbean but not the western Gulf of in the Stnit of Yucatan and northwest of . Cuba resp~ctively. DANA larvae of about In order to determine whether or not 9-10 mm were collected variously through- there was any correlation of geographical out the c{ntral and southern part of the distribution and size of larvae, size groups whole are£: occupied by larvae of less than were first selected on the basis of a plot of 20 mm. In 1920 a few such small larvae length frequency of the DANA material (Fig. occurred Lortheast of Bermuda and again 9). The larvae appear to be distributed in in 1922 ofl Cape Hatteras. four groups with frequency maxima at The FSBC specimens show that M. ed- 15-17 mm, 26 mm, 36-37 mm and 43 mm. wardsi hatches at a length of not more than The significance of these maxima is dis- about 6 mm. As immediate subsequent cussed under the section "Spawning." growth is probably quite rapid, larvae of The geographical limits of larvae within 10-20 mm almost certainly must have been the arbitrary size ranges 20 mm, 30 mm, taken not far from the area of hatching. 40 mm and 50 mm were plotted in Figure 7. Nothing is known of the incubation period It is clear that the smallest larvae occur of moringlid eggs but this is unlikely to be close to the Caribbean Islands from the Ba- more than a few days at the water tempera- hamas to the Lesser Antilles. The smallest ture in wr ich the eggs are spawned. It is CASTLE: LIFE-HISTORY OF EEL MOR/NGVA EDWARDS/ 9

Moring~ •• dulls <2dwardsi 1111I sp.wning

o ~dlJlIS ~ spliwning

Figure 8. Distribution of leptocephali and adults of Morillgua edwardsi and Neocollger I11IlCrOnalu.1 in the western North Atlantic. therefore presumed that the locations of Rubinoff, 1962) and Colombia (Castle and spawning and hatching of eggs of M. ed- Bohlke, 1976). Further, the USNM col- wardsi are more or less coincident. lection contains specimens from Florida It must be emphasized that although the (Apalachicola) as well as many other areas of distribution of the various size localities in the Caribbean. The distribution groups are limited as indicated in Figure 7 of M. edwardsi juveniles and adults is sum- anyone of the areas may contain larvae of marized in Figure 8 although not all known up to 50 mm and also metamorphic speci- localities are shown. mens. There is, however, a clear pattern of The main conclusions to be drawn from increasing size from the area of the the distribution of M. edwardsi throughout Caribbean islands out into the Western its larval life and after metamorphosis are Caribbean and most particularly out into as follows. The area in which the smallest the western North Atlantic. DANA worked larvae are to be found is that shared also many stations outside this area without col- by juveniles and adults, that is, essentially lecting larvae of M. edwardsi and it is sug- throughout the main islands of the Carib- gested that the pattern indicated in the bean. Progressively more distant areas figure is a true one. tend to include larger larvae. The implica- Juvenile and adult M. edwardsi have been tions of this are that M. edwardsi spawns in reported from Bermuda, Bahamas and the Caribbean area, that there is no sub- Greater and Lesser Antilles (Bohlke and stantial spawning migration of mature adults Chaplin, 1968). To this distribution should except perhaps offshore and that older be added Atlantic Panama (Rubinoff and larvae are transported northwards and east- 10 BULLETIN OF MARINE SCIENCE, VOL. 2~, NO.1, 1979

>- U Z w ::::> o w cr IL.

TOTAL LENGTH IN !"v,M. Figure 9. Frequency distribution of leptocephali of M. edwardsi ir the collection (0.5 em intervals). wards, particularly along the east Florida ber 1913, approx. 40oN, 52°17'W), that is, coast into the central North Atlantic. much furth ~r eastwards of all other collec- Although the Bermuda population cannot tions of la'vae of less than 30 mm total be very large because of habitat limitation lengths. L mited spawning evidently may it may support at least some spawning. The occur else""here (e.g., off Cape Hatteras). presence of this population may account for The meehanism of larval transport, as the capture of a 26 mm larva by the Danish might be e

® "DANA" @ "DANA" NOV. 1921 (5,1183-1185) FEB. 1921 (S,901"902) CarlbOUln Caribbean

APR.I911 (51.9<,J-950; W. Allanlic

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UNIV. MIAMI MAR 1912 (51.1156-1180) @ CarlbblZan JUNE (YarYI2~rs)

JULY (va •. y•• ,sI APR 1912 (51 In'-IJI4) Carlboun

AUG. 1%4

C. Allanl.c MAY 1922 l5'1Jl5-1J5>l AUG. 1969

TOTAL LENGTH (101M) Figure 10. Size distribution of leptocephali of M. edwardsi according to time of year. Open squares represent metamorphic larvae. which are dispersed by this into the central larvae reach fuIl growth. In any case they Atlantic probably do not survive: M. ed- probably do not offer a suitable habitat for wardsi has not been reported from the juveniles. Azores or the east Atlantic and these areas It is stressed that the above pattern of would seem to be beyond the limit at which size distribution and presumed dispersal is 12 BULLETINOF MARINESCIENCE,VOL.!9, NO.I, 1979

Ot..NA Slahons {SI Crold ~ ~0 . ~o ::: ~ ~ ~ ~.

I '0 I l- I I •

I :l: Ir - I :l: 30 I z ~ I ~ I ~ 10 ~ I ~ 4 0 ,..~ I•• I 10 po --=-~ I

10 13 16 113 21 25 18 ,:' DECEMBER 1911 JANUARV 1911

Figure 11. Sizes of leptocephali of M. edwardsi collected in hau s at St. Croix during December 1921- January 1922. a generalization from several different years and in nearly all months contain only large and that considerable variations from it larvae (Fig. lOc). Indeed, many of these year to year might be expected. larvae were slightly larger than any of the DANACOllfctions. SPAWNING In stror.g contrast, all collections made in the Ca:ibbean area, including the east Castle and Bohlke (1976), in their ex- coast of :?Jorida, always contained some amination of ripe males and females of small larva e (Fig. lOa, 1Od) . M. edwardsi, list 38 specimens from the M. edw'lrdsi would therefore appear to Bahamas to Colombia, collected in March spawn all :he year round in the Caribbean. and July-November of various years. Ma- That spawning may peak, however, is in- ture M. edwardsi are therefore much less dicated by the very abundant larvae taken abundant in collections than immatures, in the St. :roix area in December 1921 at probably because spawning individuals are which time there were two strong size classes pelagic and less accessible to normal collect- (Fig. lOa:. One of these (20-30 mm) ing methods. showed uI strongly again at a length of On the other hand, as indicated in Figure 35-45 mIl. in the same area in February 10, larvae of 10-20 mm occur in all months 1922. Metamorphosis of members of this of the year except September-November for size class was clearly well underway in which sampling, in any case, was limited. March-Ap~il1922. This was possibly being In 1913, 1914, and 1920 the collections contributec to by members of the succeed- of the Danish vessels BACHE,MARGRETHE, ing size class which was 10-20 mm in and DANAwere in the central West Atlantic, December 1921, spawned earlier that centered more or less on Bermuda. Al- month (Fi!;. 11). though there were a few exceptions, these Examim tion of the DANAcollection per- collections all contained relatively large mits more specific statements to be made larvae of more than 40 mm (Fig. lOb). about the spawning of M. edwardsi. The More recent collections, again in this area size frequency of larvae collected in a parti- (OCEANACRE, approx. 32°N, 64°W, URI) cular area and over a short time span (e.g., CASTLE: LIFE-HISTORY OF EEL MOR/NOVA EDWARDSl 13

DANA'STATIONS 1920-1921

50 CIJI] OJ

100 I 111 I I 51 1101211 [1 I 12121 11 I3 I3 1111LJ2]!ij1]l]jJ ~ w ITiT2TIU l2T-1 LJ 112 I 11 I I I i-I 141 12l1l a::: ~ 200 2 u.. IllTI CD IT] D LLLU~lflI!1TIJ 0 .; I ... 300 0... OJ W a

400

500 0 OJ o Figure 12. Depth distribution of hauls (squares) above 500 m during DANAStations 848-952 (western North Atlantic). Numbers in squares are numbers of larvae. S = surface. at St. Croix during December to January It implies that a new group of larvae of 1922) is plotted in Figure 11. The figure about 10 mm are being added to the larval suggests that hauls made on the same day population each month, and hence that tend to contain larvae of three size groups spawning of the adults may possibly be and that the lengths of larvae in these size related to the lunar cycle. New moon was groups tend progressively to increase as time on 29 November and 28 December 1921 proceeds. Thus, a larva of about 10 mm but the number of small specimens is in- at the beginning of December will be sufficient for a particular moon phase to around 23 mm in early January and about be associated with the appearance of 45 mm in February with metamorphosis smallest larvae. Mature M. edwardsi have (50 mm) in mid-March. This gives a larval from time to time been collected at night life of about three and a half months and lights and this may have some relationship an approximate mean growth rate of about to the final maturation of ovaries and testes. 3 mm per week during that time although larvae are unlikely to grow at the same rate DEPTH DISTRIBUTION over the whole period. Transport from the Caribbean spawning area to the central The Danish collections were made with North Atlantic thus probably takes not open, conical, stramin, or silk nets. Those more than the larval life span. most frequently used were of 150 and The pattern of larval sizes shown in 200 cm mouth diameter set in multiple Figure 11, however, suggests a further char- fashion on the towing wire at depths from acter of the spawning of M. edwardsi. the surface to 5,000 m (wire out). 14 BULLETIN OF MARINE SCIENCE, VOL. 21, NO.1, 1979

DANA' STATIONS 1921-1922.1928

o IT] 500~ 0 ~ 0 0 0 0 IT] [J

600 :,:~Ti ' 1-;'2 n I I I I 111 I I I 11 I 121 I I I I J 121 I I I 1.1 12 I I I IJJ-LL1!Jll.!.LLL Cl2 Tirn ,. iIl o !II 0 800 0 DODO OTIJ 0 0 ITTIlJI[J] rn :m : :- o .000 CD DO OIl o DO o o 00

o o CJJ

1500 o o o

2000 DO 0 DO o o o

Figure 13. Depth distribution of hauls (squares) above 2,000 ~ during DANA Stations 1183-1365 (and 3542) (western North Atlantic and Caribbean). Numbers in squares are numbers of larvae. S = surface; + = 131 larvae.

Leptocephali of M oringua edwardsi were one larva \/hich is not shown on Figure 13 collected most abundantly in the upper was collected in Haul 2, Station 1189, 300 m (i.e., in the upper 100 m actual 4,000m. depth) and progressively less so in depths These cbservations suggest that lepto- up to 4,000 m (wire out). Figures 12 and cephali of .\.1. edwardsi live more or less in 13 show the depth distributions of these the upper 35 m, though possibly not im- hauls at each positive station during the mediately at the surface. 1920-21, 1921-22 and 1928 cruises. Negative stations are not included. These COJlv:PARISON WITH Neoconger figures also serve as a reference for part of mucronatus the study material while the remainder is listed in the Appendix. Smith a:ld Castle (1972) describe the The abundance of larvae in surface life history of Neoconger mucronatus waters is shown in Figures 12 and 13, com- Girard, 18~i9, recognized in that account as pared with a very rapid fall off in the a moringui j, in fact the only other morin- numbers of larvae in the hauls below 300 guid in the Atlantic. N. mucronatus occurs (m.w.). It is suggested that the few larvae as an adult in the western Gulf of Mexico, occurring in the deeper hauls were collected Cuba and probably also as far south as while the open nets were moving to and Brazil. It ~ppears to be more typical of the from the towing positions. For example, continental shore than of the Caribbean CASTLE: LIFE-HISTORY OF EEL MORlNGVA EDWARDSl 15 islands (Fig. 8). Its larvae are widely the moringuid eels. Spec. Pubis. Dept. Ich- known in the central West Atlantic, and thyol. Rhodes Univ. 3: 1-29. spawning occurs off Brazil. More recent 1969. An index and bibliography of eel larvae. Spec. Pubis. Smith. Inst. Ichthyol. information (Charles R. Futch, pers. Rhodes Univ. 7: 1-121. comm.) indicates that this pattern may be ---, and J. E. Bohlke. 1976. Sexual dimor- an oversimplification and that there may be phism in size and vertebral number in the two distinct spawning populations centered western Atlantic eel Moringua edwardsi (An- guilliformes, Moringuidae). Bull. Mar. Sci. on the western Gulf of Mexico and off 26: 615-619. Brazil respectively, the larvae differing D'Ancona, U. 1928. Murenoidi (Apodes) del significantly in myomere numbers and pig- Mar Rosso e del Golfo di Aden. Materiali mentation. Whatever the precise pattern is raccolti dal Prof. Luigi Sanzo nella Campagna della R. N. "Ammiraglio Magnaghii" 1923- for N. mucronatus it seems likely that its 24. Memorie R. Com. Talassogr. Ital. 146: distribution as a juvenile and adult is deter- 1-146. mined by the availability of finer sediments Eigenmann, C. H. 1900. The development of and that its larvae are to be found further to the conger eel. Science, N.Y., n.s. 12: 401- the south and west than are those of M. 402. ---, and C. H. Kennedy. 1901. Unilateral edwardsi. coloration with a bilateral effect (in case of specimens of leptocephali). Science, N.Y., ACKNOWLEDGMENTS n.s. 13: 828-830. ---, and ---. 1902. The leptocephalus I wish to thank Dr. E. Bertelsen, Zoological Mu- of the American eel, and other American seum, University of Copenhagen for access to the leptocephali. Bull. U.S. Fish Commn. (1901), DANA Oceanographical Collections, and for his 21: 81-92. helpful interest and comments. Information on ad- Eldred, B. 1968. The eel larva, Leptocephalus ditional material was kindly provided by Dr. D. G. Moringua edwardsi (Jordan and Bollman, Smith, Marine Biomedical Institute, University of 1889) (Moringuidae) in the Florida Straits. Texas, Dr. W. H. Krueger, University of Rhode Florida Bd. Cons. Mar. Lab. Leaflet Ser. 4 Island and Dr. C. R. Futch, State of Florida De- (1) 6: 1-5. partment of Natural Resources. I also wish to Evermann, B. W., and M. C. Marsh. 1902. The thank Dr. G. R. F. Hicks, Victoria University, for fishes of Porto Rico. Bull. U.S. Fish Commn. his help with the study material. This study was (1900) 20: 51-350. supported by a grant-in-aid of research from the Fish, M. P. 1927. Contributions to the embry- Internal Research Committee, Victoria University ology of the American eel (Anguilla ros/rata of Wellington. Lesueur). Zoologica, N.Y. 8: 289-324. Fowler, H. W. 1944. Results of the Fifth LITERATURE CITED George Vanderbilt Expedition (1941) (Ba- hamas, Caribbean Sea, Panama, Galapagos Beebe, W., and J. Tee-Van. 1933. Field book Archipelago and Mexican Pacific Islands). of the shore fishes of Bermuda. Putnam's, Monogr. Acad. Nat. Sci. Philad. 6: 57-529. New York. 337 pp. Gill, T., and H. S. Smith. 1900. The moringuid Bohlke, J. E., and C. C. G. Chaplin. 1968. eels in American waters. Science, N.Y., n.s. Fishes of the Bahamas and adjacent tropical 11: 973-974. waters. Livingston Publishing Co., Phila- Gordon, M. S. 1954. The eels of the genus Sti/- bisel/so Copeia 1954: 11-14. delphia. 771 pp. Gosline, W., and D. W. Strasburg. 1956. The Breder, C. M. 1927. Scientific results of the Hawaiian fishes of the family Moringuidae: First Oceanographic Expedition of the "Paw- another eel problem. Copeia 1956: 9-18. nee" 1925. Fishes. Bull. Bingham Oceanogr. Herald, E. S. 1972. Fishes of North America. ColI. I: 1-90. Doubleday, New York. 254 pp. Caldwell, D. K. 1963. Marine shore fishes from Howell Rivero, Luis. 1935. Some new and rare near Puerto Limon, Caribbean Costa Rica. Cuban eels. Memorias de la Sociedad Cu- Contr. Sci. Los Ang. Count. Mus. 67: 1-11. bano de Historia Natural "Felipe Poey" 8: Castle, P. H . .1. 1965. Moringuid leptocephali in 339-344. Australasian waters. Trans. R. Soc. N.Z., Jordan, D. S., and C. H. Bollman. 1889. List of Zoo I. 7: 125-133. fishes collected at Green Turtle bay, in the 1968. A contribution to a revision of Bahamas, by Charles L. Edwards, with de- 16 BULLETIN OF MARINE SCIENCE, VOL. 29, NO. ], ]979

script ions of three new species. Proc. U.S. APPENDIX Nat. Mus. (1888), 11: 549-553. --- and B. M. Davis. 1892. A preliminary Abbreviated '.,ist of Material Examined. re~iew of the apodal fishes or eels inhabiting the waters of America and Europe. Rept. U.S. Zoological Museum, Unil'ersity of Copenlwgen Fish Commn. (1888), 16: 581-677. (ZMUC) ---, and B. W. Evermann. 1896. The fishes -----.------.------~ of North and Middle America. A descriptive DANA Statior-Haul-Number of Specimens catalogue of the species of fish-like vertebrates 848- 5- 1 950- 4-13 1216- 4- 8 found in the waters of North America, north 849- 3- 2 951- 1- 1 1216- 5-15 of the isthmus of Panama. Bull. U.S. Nat. 849- 4- 1 951- 2- 5 1218- 3- 1 Mus. 47: 1-1240. 852- 4- 1 951- 5- 2 1218- 4- 4 -- -- and H. W. Clark. 1930. A 855-18- 7 952- 1- 1 1218- 5- 2 ch~ck list of the fishes and fishlike vertebrates 855-21- 2 952- 2- 1 1223- 3- 8 of North and Middle America, north of Vene- 855-25- 1 952- 5- 2 1223- 4-16 zuela and Colombia. Rept. U.S. Fish Commn. 855-28- 2 1183- 9- 1 1223- 6- 4 (1928): 670 pp. 856- 6- 2 1183-10- 2 1225- 4-11 McAllister, D. E. 1968. The evolution of bran- 857- 4- 2 1185- 2- 1 chiostegals and associated opercular, gular 1225- 5-10 858- 2- 1 1185- 4- 1 1228- 3- 1 and hyoid bones and the classification of 858- 5- 1 1185-10- 1 1229- 3- 2 teleostome fishes, living and fossil. Bull. Nat. 861- 2- 1 1186- 8- 2 1229- 4- 2 Mus. Canada 221: 239 pp. 862- 1- 2 1186- 9-13 1230- 7- 1 Metzelaar, J. 1919. Over tropisch Atlantische 870- 6- 1 1186-10- 6 1231- 4- 5 visschen. Kruyt, Amsterdam. 314 pp. 871- 4- 1 1188- 5-15 1238- 2- 2 Nichols, J. T. 1929. The fishes of Porto Rico 873- 4- 1 1188- 6- 5 1238- 3- 4 and the Virgin Islands. Branchiostomidae to 874- 2- 1 1189- 2- 1 1238- 4-23 Sciaenidae. Sci. Surv. Porto Rico Virgo Is. 10: 876- 3- I 1189- 8- 1 1238- 5-13 161-295. 876- 4- 3 1189- 9-28 1239- 8- 4 Parr, A. E. 1930. Teleostean shore and shallow- 876- 6- 5 1189-10-44 1239- 9- 1 water fishes from the Bahamas and Turks is- 877- 1- 2 1190- 3- 9 1239-10- 4 land. Bull. Bingham Oceanogr. Coli. 3: 1- 878- 2-10 1190- 8- 9 1242- 3-12 148. 878- 3- 5 1190- 9-25 1242- 4- 3 Rubinoff, 1., and R. W. Rubinoff. 1962. Ne~ 879- 1- 1 1191- 3- 5 1242- 5- 7 records of inshore fishes from the AtlantiC 879- 2- 1 1191- 7- 2 1242- 7- 1 coast of Panama. Breviora 169: 1-7. 879- 3- 2 1191- 8- 1 1243- 3- 5 Schultz, L. P. 1953. Order Anguillida: Eels. 881- 2- 1 1192- 7- 1 1243- 4-18 Pages 43-159 ill L. P. Schultz and collabo- 884- 2- 1 1192-10- 2 1243- 5- 9 rators: E. S. Herald, E. A. Lachner, A. D. 885- 1- 1 1194- 1-40 1245- 4-19 Welander and L. P. Woods, Fishes of the 888- 2- 2 1194- 2-31 1245- 5-24 Marshall and Marianas islands. Vol. 1. Bull. 888- 3- 1 1194- 3-11 1250- 2- 3 U.S. Nat. Mus. 202. 889- 2- 2 1194- 4-27 ] 250- 3- 5 Silvester, C. F. 1916. Fishes new to the fauna 889- 4- 3 1194- 6- 2 1250- 4-29 of Porto Rico. Vb. Carnegie Instn. Wash. 891- 4- 2 1194- 7- 2 ]256- 3- 2 (1915) 14: 214-217. 892- 2- 4 1194- 8-21 ] 256- 5- 2 SMITH C. L., and J. C. TYLER. 1973. Popula- 897- 2- 1 1194- 9-21 1257- 2- 1 ti~n ecology of a Bahamian suprabenthic 901- 2- 2 1194-10- 9 1260- 4- 1 shore fish assemblage. Am. Mus. Novit. 2528: 901- 3- 3 1194-11-11 1260- 5- 1 1-38. 903- 1- 1 1196- 4- 4 1261- 4- 1 Smith D. G., and P. H. J. Castle. 1972. The eel 903- 2- 3 1196- 5- 2 1261- 5- 1 g~nus Neoconger Girard: systematics, osteol- 903- 3- 4 1196- 6- 1 1266- 4- 1 ogy, and life history. Bull. Mar. Sci. 22: 196- 943- 4- 1 1198- 4- 3 1266- 5-27 249. 944- 4- 1 1198- 5-13 1266- 7- 1 Trewavas, E. 1932. A contribution to the classi- 945- 3- 1 1202- 4- 4 1266- 8- I fication of the fishes of the order Apodes, 947- 3- 6 1202- 5- 2 1268- 2- 1 based on the osteology of some rare eels. 947- 4- 2 1214- 4- 1 1268- 3- I Proc. Zool. Soc. Lond. 1932: 639-659. 948- 1- 1 1214- 5- 4 1268- 5- 4 DATEACCEPTED: September 27, 1977. 948- 2- I 1214- 6-12 1269-10- 2 948- 3- 2 1215- 2- 1 ADDRESS: Department of Zoology, Victoria Uni- 1269-11- 8 948- 4-19 I'ersity of Wellington, Private Bag, Wellington, 1215- 6- 1 ]272- 2- 2 New Zealand. 950- 3- 2 1216- 3- 2 1272- 3- 4 CASTLE: LIFE-HISTORY OF EEL MORlNGUA EDWARDSl 17

Appendix (Continued) University of Rhode Island (OCEAN ACRE) (URl) DANA Station-Haul-Number of Specimens 1272- 4- 6 1314- 5- 4 BACHE Cruise-Station Number-Number of Specimens 1272- 5- 3 1314- 6- 2 Stations: 1273- 5- 9 \334- 6- 1 10162-2 1-31 -2 9-16 -2 \3-1 B -I 1273- 8- 1 1335-16- 1 10166-1 1-4D -2 9-29 -1 \3-2B -I 1273-10-12 1336- 6- 1 10169-1 1-17C -1 10-8M -1 \3-2M -1 1274- 5- 4 1336- 7- 4 10186-1 2-3 -2 10-38N -1 13-3OA -1 1274- 6- 1 1342-10- 4 10195-1 4-13D -1 11-2B -1 14-3P -1 1276- 2- 1 1345- 4- 4 10196-1 4-15A -1 12-1A -1 14-09P -1 1276- 5- 3 1345- 6- 2 10205-1 4-14C&D -2 12-1C -8 14-12C -1 1278- 5- 1 1345- 7- 3 10206-1 6-12C -1 12-2M -1 14-16E -3 1279- 2- 2 1352- 1- 2 10208-1 6-13C&D -1 12-34C -1 14-16P -2 1279- 4- 2 \352- 2- 7 10209-3 6-14B -1 12-87 -1 14-18M -1 1279- 5- 1 1352- 3- 7 10211-1 9-7 -1 13-1A -1 14-250 -1 1280- 5- 2 1352- 4- 2 10212-1 14-(no no.)-1 1281- 5- 1 1353- 9- 1 1281- 7- 1 1353-10- 4 DISCOVERY 1281-10- 4 1353-11- 1 Station: University of Miami Marine Laboratory (UMML) 1285- 6- 1 1355- 2- 1 709-1 1286- 2- 1 \355- 3- 1 Cruise-Number of Specimens 1286- 4- 6 1362- 6- 1 DANAII PILLSBURY 511-1 1286- 5-17 1365- 6- 1 Stations: 100-1 545-1 1287- 2- 1 3542- 1- 2 4194- 7-1 116-1 1069-3 1287- 3- 4 3542- 3- 2 4201-16-1 123-1 1076-1 1287- 4-43 128-1 1154-1 1287- 5- 7 MARGRETHE NORDBOEN 129-2 1305-2 1289- 3- 1 Stations: Station: 160-2 1306-2 1289- 4- 3 1027-1-1 680-1 170-1 1310-1 1289- 5- 3 1029-1-2 172-1 1289- 9- 2 1029-2-3 BINTANG 179-1 SL 1289-11- 1 1031-2-1 Station: 190-3 10 B-1-1 1291- 5- 2 1042-4-2 775-2 191-1 11 B-4-1 1292- 5- 4 1044-2-1 193-1 19 B-l-1 1292- 6- 4 1045-3-1 DANNEBROG 384-1 21 A-l-1 1293- 2- 2 1054-4-1 Stations: 817-1 55 B-1-1 1293- 6-10 1054-5-1 778-1 1019-1 58 B-1-1 1294- 4- 4 1056-4-1 779-1 1049-1 1296- 3- 2 1058-4-1 782-1 1105-4 TURSIOPS 1296- 4- 2 1059-3-1 784-1 11\3-4 136-1 1296- 5-15 1065-4-1 786-1 1114-3 157-1 1296- 6- 4 1072-3-1 1116-8 1314- 3- 1 1073-3-4 1122-1 ONR TOTO ------1269-2 2-6-1 1288-1 3-4-1 Florida Department of Natural Resources Marine \378-1 5-3-1 Research Laboratory Ichthyological Collection \388-8 8-3-1 (FSBC) 1389-1 10-2-1 1391-1 11-3-1 Collection Number-Number of Specimens 1392-2 13-4-1 1428-2 PF 19-1 PF 95-1 PF 417-1 Y 208-1 TOTO PF 22-1 PF 97-1 PF 421-1 Y 267-1 GERDA T-10-1 PF 63-1 PF 362-1 Y 182-1 Y 509-1 85-1 T- 7-1 PF 68-1 PF 414-1 Y 186-1 ASF 150-1 98-1 MZ 120-3 99-1 OREGON 101-1 5134-1 263-1 5422-1 497-1 5425-2 18 BULLETIN OF MARINE SCIENCE, YOLo !9, NO.1, 1979

Appendix (Continued) DANA Station-Haul-Number of Specimens 606-3-Tl-D-l SILVERBAY5189-1 606-7-Tl-C-l off Bimini, Bahamas-2 606-7-Tl-D-2 4874/A/1l-5N-2 606-7-T2-D-2 3774/ A/lO-12A-l

NGllA-4-l Carib 15-1 NGIlC-3-l Sands 74-1 Supp\. 219-1