SEEEEEEEEGEEEE5E5 Vadim D. Viadykov and Herratt March DISTRIBUTION OF LEPTOCEPHALI OF THE TWO SPECIES OF ANGUILLA IN THE WESTERN NORTH ATLANTIC, BASED ON COLLECTIONS MADE BETWEEN 1933 AND 1968 — MUSEUMS OF CANADA MUSÉES NATIONAUX DÙ CANADA OTTAWA NATIONAL Syllogeus includes papers on natural sciences and closely related topics that are not immediately appropriate for inclusion in other | publications and are issued in either English or French. Syllogeus appears at irregular intervals and individual issues are available | from the Library and the Director, National Museum of Natural Sciences, Ottawa, K1A OMB8, Canada. | La collection Syllogeus réunit un certain nombre d'articles sur les sciences naturelles ou sur des sujets qui leur sont apparentés, et qui sont publiés soit en français, soit en anglais. Les articles paraissent irrégulièrement et on peut les obtenir de Ja bibliothèque des Musées nationaux ou du cabinet du Directeur du Musée des Sciences naturelles, Ottawa, K1A OM8, Canada. Syllogeus Series No. 6 — (c) Crown Copyrights reserved — The National Museums of Canada, Ottawa, Canada, January, 1975 Litho in Canada | Distribution of lephtocephali of the two species of Anguilla in the western North Atlantic based on collections made between 1933 and 1968 Vadim D. Vladykov and Herratt March Department of Biology University of Ottawa Syllogeus No. 6 National Museum of Natural Sciences Musée national des Sciences naturelles National Museums of Canada Musées nationaux du Canada Ottawa, January 1975 TABLE OF CONTENTS ABSTRACT, 5 RESUME, 5 INTRODUCTION, 6 METHODS AND MATERIAL, 7 Collecting Details, 7 Definition of Stages of Anguilla Leptocephali, 7 Method of Identification of Two Atlantic Species of Anguilla Leptocephali, 8 Size and Geographical Distribution of Leptocephali, 9 RESULTS, 10 Role of the 50° Longitude W. as a Dividing Line, 10 Geographical Extremes of Collecting Stations for Leptocephali of Two Species of Angui//a, 10 NUMBER AND SIZE OF ANGUILLA COLLECTED IN DIFFERENT MONTHS, 11 Anguilla rostrata Leptocephali, 11 Anguilla anguilla Leptocephali, 12 Length Comparison of Two Species of Anguilla Leptocephali, 12 AGE AND TIME OF SPAWNING, 13 Age of Leptocephali, 13 Time of Spawning, 13 LIST OF TABLES, 17 FIGURES, 35 ABSTRACT Vladykov, V.D. and H. March', 1974. Distribution of leptocephali of the two species of Anguilla in the western North Atlantic, based on collections made between 1933 and 1968. For the present study, 790 leptocephali of Anguilla rostrata, from 12 mm to 69 mm, and 433 A. anguilla, from 14 mm to 79 mm, were available. These specimens were collected in the western North Atlantic between 1933 and 1968. The most extensive collections were made in 1962, 1964, 1965, and 1968. The most numerous collecting stations were established in September, with June and August next in importance. No leptocephali of either species of Anguilla were available for April and July. Longitude 50° W was an important dividing line for size distribution of Angu///a leptocephali: East of this line 23 of the largest (69 mm - 79 mm) anguilla were collected. Contrary to Schmidt’s (1925) statement, in our collections 47 rostrata were obtained east of this line. Among rostrata from both sides of this line, (on the average) somewhat larger specimens were taken east. However, the largest (69 mm) rostrata leptocephalus was caught west of this line. The smallest (less than 20 mm) rostrata in our collections were obtained in March and June. From published records it is known that leptocephali less than 10 mm were taken in February (Schmidt, 1925) and two specimens 17 mm and 22 mm were caught early in August (Smith, 1968). Therefore, it can be concluded that the American eel can spawn from February to July. In our material, A. angui//a from 14 mm to 19 mm were taken in May and June. Apparently these two months are the principal spawning period for the European eel. 'Present address: Botanical Research Institute, Pretoria, South Africa. RESUME Vladykov, V.D. et H. March' 1974. Distribution of leptocephali of the two species of Anguilla in the western North Atlantic, based on collections made between 1933 and 1968. Ce travail se fonde sur l'étude de 790 leptocéphales d’Angui//a rostrata de 12 à 69 mm et de 463 leptocéphales d'A. anguïilla de 14 à 79 mm. Ces spécimens ont été prélevés dans la partie ouest de l'Atlantique nord entre 1933 et 1968. Les échantillonnages les plus considérables ont été faits en 1962, 1964, 1965 et 1968. C'est en septembre, juin et août qu'on a réussi les plus nombreuses captures. Nous ne possédons pas de leptocéphales d’Angui//a pour les mois d'avril et de juillet. Le 50° méridien de longitude O. constitue une ligne de démarcation importante dans la distribution des leptocéphales suivant la taille. Ainsi, a l'est de ce méridien, 23 des plus longs leptocéphales d'Anguilla anguilla (de 69 a 79 mm) furent capturés. Contrairement a ce que prétend Schmidt (1925), 47 leptocéphales de l'espèce rostrata furent recueillis à l'est du 50° méridien. Les spécimens de rostrata pris a l’est de ce même méridien avaient une taille moyenne quelque peu supérieure à celle des spécimens capturés à l'ouest. Néanmoins, le plus gros leptocéphale de rostrata (69 mm) a été capturé à l'ouest du 50° méridien. Les plus petits rostrata (moins de 20 mm) que nous ayons collectionnés le furent en mars et en juin. D'après la documentation, les leptocéphales de moins de 10 mm ont été recueillis en février (Schmidt, 1925) et deux spécimens de 17 et 22 mm respectivement le furent en aout. On peut donc affirmer que l'anguille américaine peut frayer de février à juillet. D'après nos échantillons, des leptocéphales d'Anguilla anguilla mesurant de 14 à 19 mm ont été capturés en mai et juin. Tout indique que ces deux mois constitueraient la principale période de frai de l’anguille européenne. lAdresse actuelle: Botanical Research Institute, Pretoria, South Africa. INTRODUCTION Since the extensive study of Anguilla larvae in the Atlantic by Schmidt (1923, 1925), only very limited data from new collections have been made available. Taning (1938) described 46 leptocephali of both species of Anguilla captured in 1350 hauls by the Bermuda Oceanographic Expeditions, 1929-31. Smith (1968) studied 274 rostrata and 15 anguilla leptocephali from the Straits of Florida and the Bahamas. Eldred (1968, 1971) gives information for two small samples of two rostrata leptocephali each from the Yucatan and Florida Straits. The present study is based on 790 A. rostrata and 433 A. anguilla leptocephali. METHODS AND MATERIAL Collecting Details The collections of Anguilla leptocephali were made over an area from Nova Scotia to the tropical Atlantic, and from Woods Hole (Massachusetts) to the Azores, that is, from O° to 50° N. latitude and from 25° to 95° W. longitude (Figure 1). Anguilla leptocephali were collected during all months of the year except April and July by Canadian and United States research vessels between 1933 and 1968 (Table 1). Collecting by Canadian research vessels was done under the direction of the senior author, and various types of gear were employed. During the C.S.S. Hudson 1965 cruise, one-meter plankton and neuston nets were used. On the C.S.S. Baffin in 1966, tows were made with a circular 3-meter net of the type described by J. Schmidt (1929). During the C.S.S. Hudson 1968 cruise, collections were obtained with a Marinovich midwater trawl, a modification of the standard Isaac-Kidd trawl. Two models were used: 10-foot (about 3 m) and 6-foot (2 m) frames. The same type of Marinovich trawls were employed regularly by Woods Hole research vessels. The description of this trawl is given by Backus et a/. (1969). The Marinovich midwater trawl was used only for oblique tows of variable duration, but most frequently lasting 2-3 hours. Leptocephali of both species of Anguilla were more numerous in evening tows, at depths from 50 to O m, than during the daytime. The geographical position of the stations (Table 1) where rostrata and anguilla leptocephali were collected, refers to the position at which the tow started. These stations are subdivided into two categories. The principal ones refer to serial cruises and carry, in addition to consecutive station numbers, the letters RHB, indicating that the collecting was done under the direction of Dr. Richard H. Backus. The second category consists mostly of incidental collecting stations by various vessels and at different times, hence, they are ‘Miscellaneous stations’’. Altogether, Anguilla leptocephali were obtained at 99 stations, 75 of which belong to the RHB series, and 24 to the Miscellaneous ones. Some information on the collecting stations made by C.S.S. Hudson in 1965 and 1968 is given by Tibbo (1965) and Marlowe (1968) respectively. Information on collecting stations established by Woods Hole research vessels, such as the At/antis in 1938, is given by Chace (1940) and for the RHB stations 800-813 by R/V Chain by Backus et a/. (1965). Backus et a/. (1969) gave information on temperature, duration, and depth of RHB stations 1107-1132 including a map showing the position of these and some other stations. It should be noted that no replicate samples of leptocephali were available to us from the same collecting station, nor were any samples taken during the months of April and July. The number of collecting stations varied considerably from year to year. The most intensive catches were made in 1962, 1964, 1965, and 1968 (Table 2). The collecting stations were most numerous in September (Table 3). The largest number of rostrata leptocephali, 292 (together with two anguilla), was taken at RHB station 1109 on June 16, 1965, Lat. 20° 04’ N., Long. 70° 20’ W. RHB station 1316 was next in importance, where on June 26, 1966, Lat. 29° 53’ N., Long. 70° 24’ W., 91 rostrata leptocephali were obtained. The largest collections of anguilla leptocephali were made in September 1954. At RHB station 1021, Lat. 42° 24’ N., Long. 46° 00’ W., 81 anguilla and 25 rostrata were taken, and at RHB 1034, Lat. 47° 16’ N., Long. 40° 56’ W., 69 anguilla and one rostrata were obtained. Our collection consists of 790 A. rostrata leptocephali and 433 A. anguilla. The leptocephali were preserved in a 4-5% solution of formalin in sea water neutralized with borax. Definition of Stages of Anguilla Leptocephali The marine larvae of all species of Anguilla are laterally compressed, transparent, and shaped like a willow leaf (Figure 2). In younger stages, they are provided with large grasping teeth, and the anus in larvae of different sizes is located far back, the postanal length being about 30% of the total length. They then are known as ““Leptocephali’’. The larvae of A. anguilla were described by Kaup (1856) under the name of Leptocephalus brevirostris, while those of A. rostrata were named Leptocephalus grassii by Eigenmann and Kennedy (1902). An extensive bibliography on leptocephali of the Atlantic and other species of Anguilla was given by Castle (1969). According to Schmidt (1906, 1909), Gilson (1909: 34-35), and Strubberg (1913, 1923), the metamorphosis of eels can be subdivided into six stages. In stage | are included newly hatched larvae and those less than 10 mm in total length. They are called ‘’prelarvae’’ or ‘’preleptocephali’’. Jones (1968: 73) called them ‘‘protoleptocephali’’. In stages IV and V, the height of the body is a good deal less than in the previous stages, but the thickness of the body has increased. These stages may be called ‘‘transforming leptocephali’’. In stage VI the larvae, usually known as ‘glass eels’’, already have the cylindrical body of an adult eel, are toothless, and their postanal distance is more than 60% of the total length (Ford, 1931). The length of leptocephali progressively diminishes from stage IV to VI, as it does in elvers. The present paper will deal only with the distribution and growth of leptocephalus stages II-V. The glass eel (stage VI) is discussed only incidentally. The size of preserved leptocephali, glass eels, and elvers is expressed as the total length, measured to the nearest millimeter, from the tip of the lower jaw to the posterior end of the middle caudal rays. Method of Identification of Two Atlantic species of Anguilla Leptocephali Schmidt (1906, 1916) established that the number of myomeres is the principal character by which leptocephali of the two Atlantic species can be identified. Number of Myomeres The most complete information on Atlantic leptocephali is given by Jespersen (1942); however, he used only leptocephali greater than 40 mm in total length. Jespersen (1942) counted the preanal and postanal myomeres separately, ‘‘the distinction between them being given by a vertical line through the anus (Figure 3). If this vertical falls between two myomeres, the division between preanal and postanal myomeres is quite simple, but if it falls upon a segment this is included in the preanal number, and the myomeres situated behind are regarded as postanal."” Even in properly preserved, undistorted leptocephali, the counting of myomeres is not easy, particularly the most anterior and posterior myomeres. In the experience of Jespersen, ‘as first myomere is reckoned the anterior muscle segment embracing the notochord, and in the posterior part of the caudal portion the segments are, in young individuals, counted according to the number of the spinal ganglia.’” However, in our material, the spinal ganglia were not clearly visible and hence were not used in counting myomeres. Our counts of myomeres in both species of Anguilla gave lower numbers than those published by Jespersen (1942). This difference could be attributed to several causes: counting technique, different numbers of specimens, variation in size of specimens, and difference in collecting localities. Due to the fact that our counts were lower for both Atlantic species, it does not affect the identification of specimens (Tables 4-5). We encountered another difficulty familiar to all authors: in repeated counts of myomeres on the same individual, identical numbers were not always obtained. For instance, in the first count we obtained a figure of 104 myomeres, a second count could give 105 or even 106. Nevertheless, the number 104-106 identified specimens as belonging to A. rostrata. In the present study, repeated counts of 56 rostrata and 48 anguilla did not agree, therefore they are not included in Table 5. Schmidt (1925) noticed that the depth of the body of rostrata leptocephali is often greater than that for anguilla (Figure 4). This difference could not be observed in all of our samples. Position of Three Principal Blood Vessels A long row of blood vessels (arteries) runs from the dorsal aorta vertically down to the intestine and the anterior three of these are generally so conspicuous that they can be easily distinguished from the rest. Jespersen (1942) used the position of these three blood vessels, which is determined by the number of the myomere under which the vessel joins the aorta, to identify leptocephali. In general, the number of myomeres to the first vessel, counting from the head, is about half the number of myomeres to the second or third vessel. Jespersen (1942) also used the sum of the three myomere counts for identification. The difference between the number of myomeres to the second and third blood vessels is equally useful as the sum of myomeres to distinguish between leptocephali of Atlantic Angui//a species (Table 6). Size and Geographical Distribution Size Schmidt (1923, 1925) observed that fully grown leptocephali of A. anguilla are at least 10 mm. longer than those of A. rostrata. In our material, the largest rostrata leptocephalus measured 69 mm and was taken on September 4, 1964, at RHB station 1006. The longest anguilla leptocephalus measured 79 mm and was taken on September 26, 1964, at RHB station 1045. Thus, any Anguilla leptocephali taken in the North Atlantic and measuring more than 70 mm in length almost unquestionably belong to A. anguilla. Geographical distribution. Schmidt (1923, 1925) observed that in the western North Atlantic, longitude 50° W. is a dividing line for Anguilla larvae. East of it are found almost exclusively anguilla leptocephali, which are typically longer that 60 mm. Leptocephali of A. rostrata were much more numerous west of longitude 50° W. Our material confirms in broad lines the above observations by Schmidt. Therefore, the geographical position of a collecting station can be a useful but not fool-proof supplementary criterion to separate between anguilla and rostrata leptocephali. RESULTS The present paper is built on the same general lines as those presented by Schmidt (1923, 1925). Some of Schmidt's statements do not coincide with our data. Only the most important differences will be discussed. Role of 50° Longitude W. as a Dividing Line Schmidt (1925: 307-308) stated that ‘East of 50° longitude W. we have not met with larvae of the American eel.’ However, in our collections made in September 1964 there were seven stations situated between longitude 47° and 40° West, where 47 rostrata leptocephali varying in length from 41-67 mm were obtained (Table 9). It is also of importance to note that in September, 122 rostrata leptocephali (Table 13) taken west of the line were 55.6 mm on the average (range 48-69 mm), while 47 from east of the line were larger: 60.5 mm on the average (range 41-67 mm). However the largest rostrata leptocephalus, 69 mm, was taken west of the line. The size of anguilla leptocephali were much smaller, 45.2 mm on the average (range 38-68 mm), west of the line and larger, 61.0 mm on the average (range 43-79 mm), east of the line (Table 22). It appears that the large leptocephali of stage V were directed closer to their respective home waters: anguilla towards Europe and rostrata towards North America. Geographical Extremes of Collecting Stations for Leptocephali of Two Species of Anguilla Our material of A. anguilla was less numerous and collected over a smaller area than that of Schmidt. The comparison of the collecting areas is as follows: Anguilla anguilla Geographical position Northernmost find Southernmost find Westernmost find Easternmost find After Schmidt (1925:307) bat 17> 217 N., long. 10° 59 W. lat 20° A" .N.,. long. 57° 03’ W. Long. 73° 43’ W., lat. 35° 42° N. tong.) 15-35” E., lat. 38° 07’ N. Present study Lat. 47° 16’ N., long. 40° 56’ W. (RHB 1034) Lat. 19° 40’ N., long. 82° 56’ W. (RHB 1285) Long. 76° 47’ W., lat. 26° 34’ N. (Crawford ) Long. 40° 56’ W., lat 47° 16’ N. (RHB 1034) On the other hand our collecting area for rostrata leptocephali differed from that of Schmidt (1925) as follows: Geographical position Northernmost find Southernmost find Westernmost find Easternmost find Anguilla rostrata After Schmidt (1925:307) Lat. 42° 19’ N., long. 50° 22’ W. Lat. 17° 55’ N., long. 64° 48’ W. Long. 82° 59’ W., lat. 20° 08’ N. Long. 50° 22’ W., lat. 42> 1:9’ N. Present study Lat. 47° 16’ N., long. 40° 56’ W. (RHB 1034) Lat. 18° 57’N., long. 78° 47’ W. (A. Bruun) Long. 84° 23’ W., lat. 20° 38’ N. (RHB 1287) Long. 40° 56’ W., lat. 47° 16’ N. (RHB 1034) The principal difference between Schmidt's and our data lies in the fact that we collected rostrata leptocephali further north and further east than did Schmidt. We had also a single anguilla leptocephalus, taken on May 4, 1961 by the Crawford, almost three degrees further west than it was previously known. 10 NUMBER AND SIZE OF ANGU/LLA LEPTOCEPHALI COLLECTED IN DIFFERENT MONTHS The distribution and number of leptocephali collected in different months vary not only with the season but with the species as well. For this reason, each species will be treated separately in text and tables. Tables 7-10 and 15-18 refer to collecting stations and contain information on the number and range in length of leptocephali at each station. Tables 11-14 and 19-23 contain information on the length of each leptocephalus obtained at the principal collecting stations. It should be noted that Schmidt (1923, 1925) published details as to the number and length of leptocephali collected by him only at a few selected stations. This omission makes it impossible to properly compare his observations with those discussed in the present paper. Several other inadequacies of Schmidt's work were mentioned by Vladykov (1964). Anguilla rostrata Leptocephali The variation in the length of 790 rostrata leptocephali depends on the season and collecting locality. In our collections, the smallest and presumably youngest leptocephalus measured 12.3 mm and was taken at RHB Station 1116 on June 19, 1965, and the largest was 69 mm (RHB 1006, September 4, 1964). January - May During this period only 15 rostrata leptocephali ranging in length from 15 to 49 mm were obtained. No specimens were available for April. The collecting area extended from 19°00’ to 26°22’ N. latitude and from 63°58’ to 77°14’ W. longitude (Table 7). During this period two glass eels, 55 mm and 61 mm, were obtained. June The most extensive collections, 474 rostrata leptocephali, ranging from 12 to 50 mm, were made during this month. The collecting area extended from 19°40’ to 37°18’ N. latitude and from 70°13’ to 84°12’ W. longitude (Table 7). July No leptocephali were available for this month. August Ninety-five rostrata leptocephali, from 43 to 60 mm were collected during this month. The collecting area extended from 35°39’ to 40°04’ N. latitude and 66°43’ to 70°58’ W. longitude (Table 8). September During this month 149 rostrata leptocephali were obtained. The larger number, 122 leptocephali (48-69 mm), were taken west of longitude 50° W. and 47 specimens (41-67 mm) were collected east of this longitude (Table 9). The collecting area extended from 32°20’ to 47°16’ N. latitude and 40°56’ to 68°41’ W. longitude. October - December During this period 37 rostrata leptocephali (38-60 mm) were obtained. The collecting area extended from 18°57’ to 39°36’ N. latitude and 51°55’ to 82°09’ W. longitude (Table 10). Anguilla anguilla \eptocephali For the present study, 433 A. anguilla leptocephali were available. Their lengths ranged from 14.0 (RHB 813; May 10, 1961) to 78.5 mm (in tables given as 79 mm)—(RHB 1045; September 26, 1964). January - May During this period only 24 anguilla leptocephali ranging from 14 mm to 50 mm were obtained. The collecting area extended from 24°00’ to 40°20’ N. latitude and from 35°12’ to 76°47’ W. longitude (Table 15). June Only 9 anguilla letpocephali, 20-49 mm in length, were taken. The collecting area extended from 20°04’ to 37°18’ N. latitude and from 70°14’ to 70°22’ W. longitude (Table 15). July No anguilla leptocephali were available for this month. August - September In August, only 5 angui//a leptocephali were taken: one 63 mm was caught east of longitude 50° W. and four other smaller (37-51 mm) specimens west of this line (Tables 16 and 17). September collections were more numerous, consisting of 318 anguilla leptocephali. Their lengths varied according to the locality: west of longitude 50° W. the lengths of 80 leptocephali ranged from 38 to 68 mm with an average of 45.2 mm. (Table 22). East of this line 238 anguilla leptocephali from 43 to 79 mm (average 61.0 mm) were obtained. The area of collection extended from 39°19’ to 47°16’ N. latitude and from 29°09’ to 46°29’ W. longitude (Tables 16 and 17). October - December During this period 77 anguilla leptocephali, ranging in length from 34 to 59 mm, were taken. The collecting area extended from 25°06’ to 39°46’ N. latitude and from 50°15’ to 67°45’ W. longitude. (Table 18). Length Comparison of Two Species of Anguilla Leptocephali By grouping leptocephali in ten-mm classes, except those smaller than 20 mm, the following observations were made (Tables 24-25). In our collections the longest rostrata letocephalus was 69 mm while the maximum length for anguilla leptocephali was 79 (78.5) mm. Therefore, the length 70-79 mm characterized the European eel. The next smaller length class, 60-69 mm, was found in 7.6% of rostrata (Table 24) and in 28.6% of anguilla (Table 25). The occurrence of specimens in the class 50-59 mm was the same (25%) for both species. The length class of 40-49 mm contained 30.5% of anguilla leptocephali but only 16.2% of those of rostrata. The reverse is true for the class 30-39 mm, anguilla 9.2% and rostrata 38.3%. The 20-29 mm class was weakly represented (1.2%) by anguilla leptocephali but contained 12.4% of rostrata specimens. The smallest class, 12-19 mm, was represented by only four individuals of each species. 12 AGE AND TIME OF SPAWNING Age of Leptocephali Our material strongly suggests that leptocephali of both species are represented by specimens of at least two year-classes. Our data support Schmidt's observation (1923, 1925) that anguilla leptocephali spend three years at sea, but contradict his conclusion that rostrata leptocephali spend only one year at sea. It is the intention of the present authors to prepare another article dealing exclusively with the question of the duration of the leptocephalus stage of A. rostrata. Time of Spawning In our collection the smallest, and presumably youngest rostrata leptocephali, shorter than 20 mm, were taken in March and June (Table 7): on the basis of these data we can conclude that the spawning period for the American eel extends at least from March to June. Moreover, Smith (1968) reported the capture, in the Straits of Florida, of two rostrata leptocephali, 17 and 22 mm, on August 9, 1964. Futhermore, Schmidt (1925: 309) wrote that ‘‘the early tiny larvae, 7-8 mm long, of Anguilla rostrata were taken in February.’’ Therefore, it can be concluded that the American eel has a protracted spawning period, extending from February to July. In our material four leptocephali of A. angui//a ranging from 14 to 19 mm were taken in May and one specimen of 20 mm in June (Table 15). Apparently these two months are the principal spawning time of A. anguilla. ACKNOWLEDGEMENTS We are greatly indebted to several persons and institutions for collections of Anguilla leptocephali which served as a basis for the present study. Without their generous help it would have been impossible to accomplish the present work. Several collections deposited in the Harvard Museum of Zoology were made available to us through the kindness of Dr. Giles W. Mead, formerly Curator of fishes, and Mrs. M. Dick of the same institution. The bulk of leptocephali collections were generously loaned by Dr. R.H. Backus and Mr. M.R. Bartlett of the Woods Hole Oceanographic Institution. In Canada, we must mention the names of Mr. S.N. Tibbo and Dr. J.I. Marlowe of the Department of Environment under whose leadership the senior author made two collecting trips to the Caribbean Sea in 1965 and 1968. The late Capt. W. Kettle, Master of C.S.S. Baffin and later of C.S.S. Hudson, has been most helpful during the trips as were his officers and crew. Typing of the present manuscript and of the numerous tables was done most carefully by Mrs. C. Meinert. The photographs were made by Mr. G. Ben-Tchavtchavadze. Dr. E.O. Dodson kindly read the manuscript and offered many useful suggestions. They are all members of the Department of Biology, University of Ottawa. Drs. E.L. Bousfield, D.J. Faber, D.E. McAllister, and Mr. C.G. Gruchy, of the National Museum of Natural Sciences, generously provided critical advice and some financial encouragement. To all these persons and institutions the authors wish to express their most profound thanks. This study was partially supported by Grant No. A- 1736 from the National Research Council of Canada and by Grant No. 1/20-VL-vd from the National Museum of Natural Sciences, Ottawa. LITURATURE CITED Backus, R.H., G.W. Mead, R.L. Haedrich, and A.W. 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Florida Board of Conservation Marine Research Laboratory, Leaflet Series, 4, Pt. 1: 1-4. —(1971) First records of Anguilla rostrata larvae in the Gulf of Mexico and Yucatan Straits. Florida Department of Natural Resources Marine Research Laboratory, Leaflet Series, 4, Pt. 1: 1-3. Ford, E. (1931) Changes in length during the larval life and metamorphosis of the freshwater eel (Anguilla vulgaris Turt.). J. Marine Biol. Ass. of the United Kingdom, 17 n.s. 1931: 987-1000. Gilson, G. (1909) L’anguille. Sa reproduction, ses migrations et son intérêt économique en Belgique. Annales de la Société Royale Zoologique et Malacologique de Belgique, 1908, 43: 7-58. Jespersen, P. (1942) Indo-Pacific leptocephalids of the genus Anguilla. Dana-Rep. 22: 1-127. Jones, F.R.H. (1968) Fish migration. Edward Arnold Ltd. London. viii. Kaup. J.J. (1856) Catalogue of apodal fish in the collection of the British Museum, London. Marlowe, J.I. (1968) Cruise Report No. 209, C.S.S. Hudson, January 24 - April 11, 1968. Atlantic Oceanographic Laboratory, Bedford Institute. Schmidt, J. (1906) Contribution to the life-history of the eel (Anguilla vulgaris Flem). Rapp. P. -v. Réun. Cons. Perm. Int. Explor. Mer, 5: 137-274. —(1909) Remarks on the metamorphosis and distribution of the larvae of the eel (Anguilla vulgaris Turt.). Medd. Kommn. Havunders., Fiskeri, 3. —(1916) On the early larval stages of the fresh-water eels (Anguilla) and some other North Atlantic Muraenoids. Medd. Kommn. Havunders, Fiskeri, 5. —(1923) The breeding places of the eel. Phil. Trans. Roy. Soc. London. Series B, 211: 179-208. —(1925) The breeding places of the eel. Smithsonian Report for 1924: 279-316. —(1929) Introduction to the oceanographical reports. Oceanogr. Rep. ‘‘Dana’’ Exped., 1. —(1935) Danish eel investigations during 25 years, 1905-1930. Carlsberg Foundation, Copenhagen. Smith, D.G. (1969) The occurence of larvae of the American eel, Anguilla rostrata, in the straits of Florida and nearby areas. Bull. Marine Science, 18: 280-293. Strubberg, A.C. (1913) The metamorphosis of elvers as influenced by outward conditions. Medd. Kommn. Hav. Fisk., 4. —(1923) Elvers from north and south Europe. Dana Rep't. 3(4). Taning, A.V. (1938) Deep-sea fishes of the Bermuda Oceanographic Expeditions. Family Anguillidae. Zoologica, 23: 313 - 318. Tibbo, S.N. (1965) Cruise Report No. 102. C.S.S. Hudson February 1-27, 1965. Bedford Institute of Oceanography. Viadykov, V.D. (1964) Quest for the true breeding area of the American eel (Anguilla rostrata LeSueur). J. Fish. Res. Board Can. 21:1523-1530. LIST OF TABLES ie 10. nel. 12. 13. 14. 16. 16. ae 18. List of collecting stations in the western North Atlantic where Anguilla leptocephali were obtained between 1933 and 1968. Number of collecting stations established and number of Anguilla leptocephali obtained yearly in the western North Atlantic between 1933 and 1968. The number of collecting stations for Anguilla leptocephali established according to months in the western North Atlantic between 1933 and 1968. Number of preanal and postanal myomeres in leptocephali of two species of Anguilla collected from 1938 to 1968. Comparison between the total number of myomeres in leptocephali of two Atlantic species of Anguilla in the present study and those given by Jespersen (1942). Number of myomeres in leptocephali of two species of Anguilla at the levels of the three most distinct anterior vertical blood vessels. List of collecting stations in the western North Atlantic where leptocephali of Anguilla rostrata were obtained from January to June 1938-1968. List of collecting stations in the western North Atlantic where leptocephali of Anguilla rostrata were obtained in August during 1953-1968. List of collecting stations in the western North Atlantic where leptocephali of Anguilla rostrata were obtained during September, 1962 and 1964. List of collecting stations in the western North Atlantic where leptocephali of Anguilla rostrata were obtained from October to December, 1964-1968. Number and length of leptocephali of Anguilla rostrata obtained at selected RHB stations in the western North Atlantic during June 1965-1966, with totals for all stations for the same month (see Table 7). Number and length of leptocephali of Anguilla rostrata obtained at selected stations in the western North Atlantic during August 1953-1968, with totals for all stations for the same month (see Table 8). Number and length of leptocephali of Anguilla rostrata obtained at selected RHB stations in the western North Atlantic during September 1962 and 1964, with totals for ail stations located west or east of longitude 50° W. (see Table 9 for complete list of stations). Number and length of leptocephali of Anguilla rostrata obtained in the western North Atlantic during October-December, 1964-1968 (see Table 10). List of collecting stations in the western North Atlantic where leptocephali of Anguilla anguilla were obtained from January to June, 1933-1968. List of collecting stations in the western North Atlantic, west of longitude 50 W. where leptocephali of Anguilla anguilla were obtained during August and September, 1962-1967. List of collecting stations in the western North Atlantic, east of longitude 50 E, where leptocephali of Anguilla anguilla were obtained during August and September, 1964 and 1966. List of collecting stations in the western North Atlantic where leptocephali of Anguilla anguilla were obtained from October to December, 1964 and 1968. 17 19. 20. 24 an 23. 24. 25. 18 Number and length of leptocephali of Anguilla angui/la obtained in the western North Atlantic during January-March, 1933-1968 (see Table 15 for complete list of stations). Number and length of leptocephali of Anguilla anguilla obtained in the western North Atlantic during May-June, 1961 and 1965 (see Table 15 for complete list of stations). Number and length of leptocephali of Anguilla anguilla obtained at selected stations in the western North Atlantic during September 1962 and 1964, with totals for all stations located west or east of longitude 50° W. (see Tables 16 and 17 for complete list of stations). Number and length of leptocephali of Anguilla anguilla collected at different stations during September 1962 and 1964, east and west of longitude 50 W. (see Tables 16 and 17 for complete list of stations). Number and length of leptocephali of Anguilla anguilla obtained in the western North Atlantic from October to December, 1964-1968 (see Table 17 for complete list of stations). Number and length of Anguilla rostrata leptocephali collected monthly in the western North Atlantic between 1933-1968. Number and length of leptocephali of Anguilla anguilla collected monthly in the western North Atlantic between 1933-1968. bhi = om Be Table 1. Station No. 467 484 555 587 588 813 857 861 862 863 866 867 869 1063 1004 1006 1008 1010 1011 1013 1014 1018 1019 1020 1021 1022 1023 1024 1025 1031 1034 1035 1036 1045 1046 1047 1050 1052 1053 1054 1055 1109 LAS 1116 1K re 1118 1121 1123 1129 1132 1285 1287 1312 1316 1502 1503 1505 1506 1509 1512 List of collecting stations in the western North Atlantic where Anguilla leptocephali were obtained between 1933 and 1968. Vessel Date Year Blue Dolphin Aug. 19/20, 53 i Aug. 26, 53 Atlantis Feb. 10, 54 EX Mar. 21, 54 Mar. 21, 54 Chain May 10/11 61 7 Sept.14/15, 62 Sept. 15, 62 Sept. 17, 62 Sept. 18, 62 Sept. 18, 62 Sept. 19, 62 Sept.19/20, 62 Atlantis II Sept. 3, 64 pe Sept. 4, 64 Sept. 4, 64 Sept. 5, 64 Sept. 5, 64 Sept. 6, 64 Sept. 6, 64 Sept. 7, 64 Sept. 9, 64 Sept. 9, 64 Sept. 9, 64 Sept. 9, 64 Sept. 10, 64 Sept. 10, 64 Sept. 10, 64 Sept. 11, 64 Sept. 13, 64 Sept. 13, 64 Sept. 17, 64 Sept. 19, 64 Sept. 26, 64 Sept. 27, 64 Sept. 27, 64 Sept. 29, 64 Sept. 30, 64 Oct; 64 Ocinl, 64 Oct.2; 64 Chain June 16, 65 4 June 18, 65 June 19, 65 June 19, 65 June 19, 65 June 20, 65 June 20, 65 June 22, 65 June 23, 65 June 9, 66 June 10, 66 June 24, 66 June 26, 66 Aug. 24, 67 Aug. 24/25, 67 Aug.25/26, 67 Aug. 26, 67 Aug.26/27, 67 Aug. 27, 67 Lat. RHB stations 39° 39° 25° 26° 26° 27 41° 41° 40° 40° 39° 39° 39° 41° 41° 41° 41° 41° 41° 41° 41° 41° 41° 42° 42° 42° 43° 44° 44° 47° 47° 46° 42° 39° 39° 39° 39° 39° 39° 39° 39° 20° 24° 24° 25° 25° 27 28° 34° 37° 19° 20° 23° 29° 40° 39° 37° a7 35° 35° N. Sue 40° 26° 224 18° 30° 593% 40° 00° 03° 20° 03° 07’ 36° 29) 16° 24° 31 33) 36° 34° 727 a3) 05° 24° 35° 16° O07’ 184 14 16° 16° 20° 34° 30° 251 Sil oh 26° 36° 46° 04° 251 SIT 18° 29% 28° 28° 12’ 18° 40° Se 53: 53: 04 10° 40° 372 39) 42° Position Long. W. 70° 70° 76° 76° 76° 54° 625 61° 66° 66° 66° 67° 68° 60° 60° 57° 56° 55: 54° 52° 522 47° 46° 46° 46° 45° 45° 44° 44° 41° 40° 35) 29° 352 35: 36° 43° 47° 50° ei Le 54° 70° 70° 70° TOF 70° JOF 0; 70° 70° 82° 84° 83° Ugh 67° 67 66° 66° 67° 67° 58° 43° 03° 10° 05° 05° 43° 57 20° 40° 45° 18° 41° 30° 14° 370 112% Wal 55) 21 on (51 44° 29° Ue 56° 03° 09° dit 56° 56° 29) 09° Sid 58° 56° 331 45° (lon 55: ome 20° 21% iy 14° 13% 24° gh 7a ||" 22% 58° 112 223 24° Tiss 20° 50° 43° Aes 32, Number of Anguilla leptocephali anguilla rostrata ren On NN = | = = N OO O = = N OO © N = O1 NN = : = —_ -N 1 No = © COTON COS INT ER ee ery nas as = i= fy, 1 = N ©'O 1 Nit - © 19 Station Vessel Date Year Position Number of Angui//a leptocephali No. Lat. N. Long. W. rostrata anguilla RHB stations 1513 ga Aug. 27/28, 67 35°47" O7A33) 6 1 1704 cs Nov. 27/28, 68 30° 30° 67027: 5 6 1705 ÿ Nov. 28, 68 30° 16° 67° 34° 11 1 Oe fa WP i Nov. 30, 68 252 tlh 67° 41° - 5 1713 # Dec. 1, 68 25406! 67° 45° - 1 1722 iz Dec. 5, 68 25° 40.5' Gia 5) 1 = 1723 Xd Dec. 5/6, 68 25° 39' 67° 43 2 41 1724 + Dec. 6, 68 25259" 67° 24° 1 = 1725 a Dec. 6, 68 26° 06° 67° 16 = 1 1727 a Dec. 6/7, 68 26° 46° 67232; 4 10 1728 + Dec. 7; 68 26453) (zi Shei 1 = 1731 # Dec. 7, 68 28° 02' Ove Ss) - 1 1797 5 Dec. 8, 68 28° 45' 67> 26° 1 1740 LE Dec. 10, 68 31931 (7 She 3 1741 SE Dec. 10/11, 68 SOF 67934: 1 2 Miscellaneous stations 1472 Atlantis Feb. 17, 33 27056! US DSi - 1 2945C à Jan. 6, 38 B55 0s 674301) - 6 2947A bia Jan. 30, 38 25° 16° 77° 14° 1 = Da Feb. 2, 52 29299: 35112: - 1 Crawford May 4, 61 26° 34° 76° 47° - 1 te May 7, 61 20° 53° 73° 59° 2 = May 19, 61 28° 02’ 76° 34’ 7 = 6314-15 Atlantis Sept. 24, 62 33° 28° 64° 06° - 1 6316-17 fs Sept. 24/25, 62 32250) 64° 04’ 2 17 6319-20 re Sept. 26/27, 62 32° 24° 64° 05 1 2 6321-22 ¥ Sept. 27/28, 62 32220: 639381 4 45 39 Hudson Feb. 23, 65 34° 537 75428} 1 (G)! - 13 Baffin Mar. 27, 66 24° 00° 63° 45' - 4 Hudson Aug. 4, 66 45° 34’ 27/256" - 1 824 Anton Bruun Octil3; 66 TS Size 182476 1 = 827 eg? ath Oct. 13, 66 19° 46° 82° 09' 1 = Atlantis I/ Jan. 15, 67 28° 50° 62° 26° - 1 287 Panulirus | Jan. 18, 68 32410! 64° 30° - 1 3 Hudson Jan. 27, 68 40° 20° L9SS8 7 1 (G)! 2 5 i Jan. 29, 68 36° 04' 63° 08’ - 2 7 es Jan. 31, 68 3022 6522 - 1 12 te Feb. 5, 68 19° 00° 63258: 1 = 20 Crawford Aug. 11, 68 39° 10’ 69° 44.6’ 4 - 21 É Aug. 11, 68 39° 49.4° 682241 1 - 'Glass eel stage 20 Table 2. Number of collecting stations established and number of Anguilla leptocephali obtained yearly in the western North Atlantic between 1933 and 1968 Year Number of Number of leptocephali Stations rostrata anguilla 11933 1 — 1 1938 2 1 6 1952 1 _ 1 1953 2 42 = 1954 3 4 = 1961 4 9 5 1962 11 65 66 1964 28 112 257 1965 10 380 9 1966 8 96 5 1967 8 48 5 1968 21 33 78 Total 99 790 433 Table 3. The number of collecting stations for Anguilla leptocephali established according to months in the western North Atlantic between 1933 and 1968. MONTH YEAR and STATIONS (in parentheses) TOTAL NUMBER Years Stations January 1938(2), 1967(1), 1968(4) 3 7 February 1933(1), 1952(1), 1954(1), 1965(1), 1968(1) 5 5 March 1954(2), 1966(1) 2 3 May 1961(4) 1 4 June 1965(9), 1966(4) 2 ile August ASS) ENS EEE TIC) 1968 (2) 4 12 September 1962(11), 1964(25) 2 36 October 1964(3), 1966(2) 2 5 November 1968(3) 1 3 December 1968(11) 1 11 Table 4. Number of preanal and postanal myomeres in lep- tocephali of two species of Anguilla collected from 1938 to 1968. Species A. rostrata A. anguilla Number of specimens 707 379 Myomeres Mean Range Mean Range Preanal 69.45 64-74 70.86 67-75 Postanal 34.72 31-40 40.74 38-48 21 22 Table 5. Comparison between the total number of myomeres in leptocephali of two Atlantic species of Anguilla in the present study and those given by Jespersen (1942). Myomeres Anguilla rostrata Anguilla anguilla Number of specimens Number of specimens Present Jespersen Present Jespersen study (1942) study (1942) 101 4 = = - 102 11. = = - 103 74 - - - 104 1153 1 = = 105 205 6 = = 106 N75 18 = = 107 719 51 = = 108 29 101 = = 109 5 68 i - 110 1 34 55 - 111 - 7 106 = 2 = = 101 1 We = = 79 20 114 = = 24 65 ANS) = = 8 139 116 = - 1 142 1181174 = = - al) 118 = - - 25 119 = - - 3 Total 736 286 385 472 Mean OS eas TOSS 7 1 76 115258 Table 6. Number of myomeres in leptocephali of two species of Anguilla at the levels of the three most distinct anterior vertical blood vessels. Number of specimens studied: A. rostrata - 150; A. anguilla - 100 Blood vessels (B.V.) Wh B.V. il B.V. Sum of 3 blood vessels — al Ba: (++ B.Vs.) Mean Anguilla rostra Range 16-20 36-43 42-46 2-7 95-10 ta 8 1 06.10 Anguilla anguilla Range 17-20 39-43 45-49 5-8 102-111 Table 7. List of collecting stations in the western North Atlantic where leptocephali of Anguilla rostrata were obtained from January to June, 1938-1968. Date Jan. 30, Feb. 10, Feb. 5, Mar. 21, Mar. 21, May 7, May 19, June 16, June 18, June 19, June 19, June 20, June 20, June 22, June 23, June 9, June 10, June 24, June 26, Jan. 27, Feb. 23, Station Atlantis 555 RHB Hudson 587 RHB 588 yi Crawford 1109 RHB WG Wiss 4 vi; Apts WiAsy MZ? oN 1is2 >" 285°” 12870 EM US 4 Hudson 34° 53’ Position Long. W. TT 76% 63° 76° 7162 Tse 76° 70° 70° 70° 70° 70: 70° 70° 70° 82° 84° 83° 79° 14’ 03’ 582 10’ 05’ DEF 34’ 20’ 21 15’ 182 24’ 19’ 21 222 58’ 12: aoe 24’ Glass eels aoe 75ù 37’ 23! Leptocephali Range (in mm) 49 46 49 15-17 48 29-34 26-36 20-52 21-39 12-39 41 43 43 44 44 41 38 43 21-50 23 Table 8. List of collecting stations in the western North Atlantic where leptocephali of Anguilla rostrata were obtained in August during 1953-1968. Date Station Position Leptocephali Lat. N. Long. W. N Range | (in mm) | Aug. 19/20 53 467 RHB 3975 JOM5E! 36 44-57 Aug. 26, 53 484 RHB 39° 40’ 70° 43’ 6 43-49 Aug. 24, 67 1502 RHB 40° 04’ GAS 1122 45-60 Aug. 24/25, 67 1503 RHB 39310: 67° 20’ 4 49-52 Aug. 25/26, 67 1505 RHB 37° 40’ 66° 50’ 3 49-54 Aug. 26, 67 1506 RHB Sis SL 66° 43’ 19 43-56 Aug. 26/27, 67 1509 RHB 350091 A 7E 1 58 Aug. 27, 67 1512 RHB 35% 42: C7 3 54-59 Aug. 27/28, 67 1513 RHB 35° 472 677 6 54-60 Aug. 11, 68 Crawford: 20 S9MAIO: 69° 44.6’ 4 48-51 Aug. 11, 68 Crawford: 21 39° 49.4’ 68= 24M" 1 48 Table 9. List of collecting stations in the western North Atlantic where leptocephali of Anguilla rostrata were obtained during September, 1962 and 1964. Date Station Position Leptocephali Lat. N. Long. W. N Range (in mm) Sept. 15, 62 861 RHB 41° 40’ CIEL 1 58 Sept. 17, 62 862 ù 40° 00’ 66° 20’ 2 59-61 Sept. 18, 62 863 1 40° 03’ 66° 40’ 227) 50-60 Sept. 18, 62 866 i SoZ! 66° 45’ 25 49-64 Sept. 19, 62 867 Ë 3908! 6787 1 58 Sept. 19/20, 62 869 Ÿ SC (071 68° 41’ 2 55-60 Sept. 24/25, 62 Atlantis 286-3 322850! 64° 04’ 2 51-54 Sept. 26/27, 62 "286-4 32° 24’ 64° O5 1 51 Sept. 27/28, 62 M 2865 3228201 63% 337 4 51-57 Sept. 3, 64 1003 RHB Ae 336" 60° 30’ 13 50-60 Sept. 4, 64 1004 " Ail? 29" 60° 14’ 6 52-62 Sept. 4 64 1006 " 41° 16’ ONE )7/0 12 51-69 Sept. 5 64 1008 " 41 24’ 562 1724 1 56 Sept. 5 64 TOO AS 550 die 1 54 Sept. 6, 64 TOM AN ile Sich 54° 55’ 16 48-60 Sept. 6, 64 1013 41° 36’ HDI 6 58-63 Sept. 7 64 NON 41° 34’ 525 elise 2 58-61 Sept. 9 64 is} A = 27" ANGL 1 61 Sept. 9 64 1009) Aa me) 46° 44’ 1 65 Sept. 9, 64 1OZT a 42° 24’ AG 25 53-67 Sept. 10, 64 1O22N, AD 3 57 45° 56¢ 12 55-61 Sept. 13, 64 1OS4 AT eG: 40° 56’ 1 55 Sept. 29, 64 1OSOMN ee Gr 43° 33’ 1 65 Sept. 30, 64 1OS2 Sig); IS 47° 45’ 6 41-65 24 Table 10. List of collecting stations in the western North Atlantic where leptocephali of Anguilla rostrata were obtained from October to December, 1964-1968. Date Station Lat. Oct: 15 64 1054 RHB 39° Oct 13, 66 Anton Bruun:11 18° Oct 13; 66 Anton Bruun:12 19° Nov. 27/28, 68 1704 RHB 30° Nov. 28, 68 1705 30° Dec. 5, 68 722) 255 Dec. 5/6, 68 17280 25à Dec. 6, 68 1724 " 252 Dec. 6/7, 68 172700 26° Dec. 7, 68 i723 26° Dec. 10, 68 AO AL Silly Dec. 10/11, 68 7A ee Site Table 11. Number and length of leptocephali of Anguilla rostrata obtained at selected RHB stations in the western North Atlantic during June 1965-1966, with totals for all stations for the same month (see Table 7). Number of leptocephali collected Length 16-65 18-65 19-65 26-66 Total for (mm) 1109 aids 1116 1316 June 12 = - 1 - 1 18 = = 1 - 1 20 1 = = - 1 1 - 2 = 3 Z = = = = = 3 3 72 1 - 6 4 2 1 1 - 4 5 4 5 = = 9 6 6 6 1 - 13 7 9 12 1 - 22 8 6 7 = 1 14 9 16 4 1 1 22 30 20 5 = 3 28 1 24 8 = 5 37 2 19 6 1 4 31 3 28 4 1 3 36 4 24 1 - 2 27 5 23 4 - 7 34 6 23 1 1 6 31 7 18 - 1 8 27 8 19 - 1 5 26 9 10 2 1 7 20 40 17 - - 12 29 1 6 = - 9 17 2 3 = - 3 6 3 4 - - 2 8 4 22 = = 4 8 5 3 = - 5 8 6 1 - - 1 2 7 - - - 1 1 8 ss = = ne = 9 = = = = a 50 - - - 1 1 1 = = = = = 2 1 - - ~ 1 Total 292 70 13 on 474 ——_—_—_—_—_—_—_———————————————————…—…—…—…—…—…—…—…—…—…—…—…—…—…"…"…"—"—"—" —"———— = The first figures refer to the day of the month, and the second, to the year. Position Long. W. ie aby Orneaaehe 82° O9 670276 67° 34 67> 35% 67° 43’ 672 24" 672082: (ie Sis Gis Sila 67° 34’ Leptocephali N Range (in mm) 8 57-63 1 38 1 53 5 52-60 1 50-55 1 42 2 40-47 1 49 4 52-57 1 55 1 55 1 60 25 Table 12. Number and length of leptocephali of Angui//a rostrata obtained at selected stations in the western North Atlantic during August 1953-1968, with totals for all stations for the same month (see Table 8). Number of leptocephali collected Length 19/20-53? 26-538 24-67? 26-67 11-68? Total (mm) RHB RHB RHB RHB Crawford” 1953-1968 467 484 1502 1506 20-21 43 - 1 = 1 = 2 4 1 1 - - - 2 5 = 1 1 - - 2 6 1 - 1 3 - 5 7 1 - - 1 - 2 8 3 1 - 3 2 9 9 4 2 3 2 1 14 50 6 - 3 5 1 15 1 8 - 1 2 1 12 2 2 - 1 - - 7 3 6 - 1 1 - 8 4 1 - ~ - - 5 5 1 - - - - 2 6 - - - 1 - 2 7 2 - - - - 4 8 - - - - - 1 9 - - - - - 1 60 - - 1 - - 2 Total 36 6 12 19 5 95 a The first figures refer to the day of the month, and the second, to the year. b Collections of leptocephali made at two stations (20 & 21) of Crawford cruise 172 are combined. Table 13. Number and length of leptocephali of Anguilla rostrata obtained at selected RHB stations in the western North Atlantic during September 1962 and 1964, with totals for all stations located west or east of longitude 50°W (see Table 9 for complete list of stations). Length Number of leptocephali collected Total (mm) 863 866 1003 1006 1011 1021 West East Grand total 41 = = = = = = = 1 1 48 - - - - 1 = 1 - 1 49 - 7) - - ~ ~ 2 - 2 50 1 1 1 - ~ - 3 - 3 1 4 2 - 1 - - 10 - 10 2 2 1 2 - 1 - 8 = 8 3 2 5 - - 2 1 9 1 10 4 8 3 1 1 4 1 iS) 3 22 5 4 4 1 1 1 - 12 4 16 6 4 3 2 1 3 - 16 2 18 7 - 1 1 - 2 - 5 1 6 8 = - 2 - 1 2 ©) 2 11 9 _ 1 2 1 - 2 6 4 10 60 2 - 1 3 1 - 10 4 14 1 = - - 3 - - 6 3 9 2 - 1 - - - 2 3 3 6 3 = = = - - 2 1 2 3 4 = 1 = - - 4 1 4 5 5 = = = = - 4 - 7 7 6 = = - - - 3 - 3 3 7 = = - - ~ 3 - 3 3 8 = = = = = = = = = 9 - - - 1 - - 1 - 1 Total 27 25 VE 12 16 25 122 47 169 27 Table 14. Number and length of leptocephali of Anguilla rostrata obtained in the western North Atlantic during October - December, 1964-1968 (see Table 10). Months Length October November December Total (mm) 3 stations 2 stations 7 stations 12 stations 38 1 - ~ 1 40 - - 1 1 1 = = = = 2 - - 1 1 3 = = = = 4 = 2. = = 5 2 3 _ = 6 = = = = 7 - - 1 1 8 = = = = 9 - - i 1 50 - 1 ~ 1 1 = 3 = 3 2 - 1 1 2 3 1 - - 1 4 - 6 1 7 5 - 3 3 6 6 = zs = = 7 1 - 1 2 8 - 1 - 1 9 2 - - 2 60 1 1 1 3 1 2 - - 2 2 1 - ~ 1 3 1 - - 1 Total 10 16 11 37 Table 15. List of collecting stations in the western North Atlantic where leptocephali of Anguilla anguilla were obtained from January to June, 1933-1968. Date Station Position Leptocephali Lat. N. Long. W. N Range (inmm) Jan. 6, 38 Atlantis S550! CS O0! 6 39-46 Jan. 15, 67 Atlantis 1! 28° 50! 62° 26’ 1 46 Jan. 18, 68 Panulirus | 322710! 64° 30’ it 45 Jan. 27, 68 Hudson 40° 20’ Sosy” 2 46-50 Jan. 29, 68 Me 36° 04’ 63° 08’ 2 47-48 Jan. 31, 68 Ÿ SOF 822) 652! 1 42 Feb. 17, 33 Atlantis 2756! 739053: 1 SH Feb. 2, 52 292922; 35012: 1 39 Mar. 27, 66 Baffin 24° 00’ 63° 45’ 4 37-41 May 4, 61 Crawford 26° 34’ 76° 47’ 1 46 May 10/11, 61 813 RHB 272030! 54° 05’ 4 14-19 June 16, 65 AIO SN 20° 07 1000! 2 28-32 June 19, 65 AIMENT 24937: TOP iS! 5 20-30 June 19, 65 ZA 258; 70° 14 1 33 June 23, 65 ITSZ2NNL By i \tske 702227 1 49 28 Table 16. List of collecting stations in the western North Atlantic, west of longitude 50°W, where leptocephali of Anguilla anguilla were obtained during August and Setpember, 1962-1967. Date Station Position Leptocephali Lat. N. Long. W. N Range (in mm) Aug. 26, 67 1506 RHB Sin Oe 66° 43’ 3 37-47 Aug. 27/28, 67 l'ISS 35> A477 (Wy SS)" 1 51 Sept. 14/15, 62 O7 41° 53’ 62° 43 1 68 Sept. 24, 62 Atlantis 393028) 64° 06’ 1 40 Sept. 24/25, 62 2 322850! 64° 04’ 17 40-48 Sept. 26/27, 62 " 7e 2 64° O5 2 38-40 Sept. 27/28, 62 322201 6329881 45 41-51 Sept. 4, 64 1006 RHB Ae 16% SENS 7 2 59-66 Sept. 5, 64 1010 RHB iles 6117 DAME 6 41-49 Sept. 6, 64 1011 RHB 4158337 DANSE 3 41-57 Sept. 6, 64 1013 RHB 41° 36’ Beale 2 44-47 Sept. 7, 64 1014 RHB 41° 34 BAe {5 1 61 Table 17. List of collecting stations in the western North Atlantic, east of longitude 50°W, where leptocephali of Anguilla anguilla were obtained during August and September, 1964 and 1966. Date Station Position Leptocephali Lat. N. Long. W. N Range (inmm) Aug. 4, 66 Hudson 45° 34’ 272050! 1 63 Sept. 9, 64 1020 RHB 42° 05’ 46° 29’ 1 58 Sept. 9, 64 O21 © 42° 24’ 46° 11’ 81 52-70 Sept. 10, 64 102220 42° 35’ 45° 56’ 17 43-62 Sept. 10, 64 1023 =" 4324167 45° 03’ 1 58 Sept. 10, 64 1024 " 44° O7’ 44° 09’ 5 58-72 Sept. 11, 64 1025 44° 13’ 44° 11’ 3 52-57 Sept. 13, 64 TOS 47° 14 41° 567 1 73 Sept. 13, 64 1034 " 47° 16’ 40° 56’ 69 56-77 Sept. 17, 64 1035." 46° 16’ 350291 3 65-75 Sept. 19, 64 10367 42° 20’ 29> 1097 3 69-76 Sept. 26, 64 1045 * 39° 34’ 33800837 6 57-79 Sept. 27, 64 1046 " Sieh Sho) 35581: 2 70-72 Sept. 27, 64 1047 " 392025) 36% 561 2 7 Sept. 29, 64 1050 " Se Syl 43° 33’ 32 52-75 Sept. 30, 64 1052 " Sey iG 47° 45’ 12 43-56 29 Table 18. List of collecting stations in the western North Atlantic where leptocephali of Anguilla anguilla were obtained from October to December, 1964 and 1968. Date Station Position Leptocephali LATIN" Long. W. N Range (in mm) Oct. 1, 64 1053 RHB 39° 26’ HOME: 2 51-53 Oct 1, 64 1OSAM ™ 392367 Gi 5 1 59 Oct. 2, 64 THOSE 39° 46’ SAS TL 2 51-55 Nov. 27/28, 68 1704 " 3080! C7272 6 41-45 Nov. 28, 68 (705). 4 SHO 67° 34’ 1 45 Nov. 30, 68 ei ? 215 ae i 67° 41’ 5 37-41 Nov. 30/ Dec. 1, 68 iiss 252106: 67° 45’ 1 36 Dec. 5/6, 68 17238 ZI Sieh Gi 431 41 34-45 Dec. 6, 68 2 26°) 106% 67° 16’ 1 43 Dec. 6/7, 68 War 26° 46’ 7 677 10 40-45 Dec. 7, 68 11726) 1] NC 280402: 67233 1 44 Dec. 8, 68 1174572 28° 45’ 67267 1 44 Dec. 10, 68 1740 +" Sion G72 si 3 40-45 Dec. 10/11, 68 AG ee a1 SC 67° 34’ 2 45-47 Table 19. Number and length of leptocephali of Anguilla Table 20. Number and length of leptocephali of Anguilla anguilla obtained in the western North Atlantic anguilla obtained in the western North Atlantic during January-March, 1933-1968 (see Table 15 during May-June, 1961 and 1965 (see Table for complete list of stations). 15 for complete list of stations). Number of leptocephali collected Number of IeEteeeniey collected Length = January? February? March°) Total Length May° June” Total eat 1938 & 1968 1933 & 1952 1966 1933-1968 (mm) 1961 1965 1961-1965 57 = 1 1 2 14 1 = 1 39 1 1 1 3 18 1 = 1 40 1 = 1 2 19 2 = 2 1 1 - 1 2 20 = 1 1 2 1 bd ~ 1 21 — 1 1 3 1 ial a 1 25 — 1 1 4 1 & L 1 28 — 2 2 5 1 - = 1 30 = 1 1 6 3 Ss az 3 32 — 1 1 7 1 È = 1 33 — 1 1 8 1 aS … 1 46 1 — 1 50 1 me = a 49 — 1 1 Total 5 9 14 Total is 2 4 19 a 2 stations a 5 stations b 4 stations b 2 stations c a single station 30 Table 21 Number and length of leptocephali of Anguilla angui/la obtained at selected stations in the western North Atlantic during September 1962 and 1964, with totals for all stations located west or east of longitude 50° W (see Tables 16 and 17 for complete list of stations). Number of leptocephali collected Total Atlantis RHB RHB RHB West East Grand total 286-5 1021 1034 1050 - - - - 1 ~ 1! = = - - 3 - 3 2 - - - 8 - 8 9 - = - 14 - 14 5 = = = 7 22 9 10 - - - ies - 13 8 - - - 12 - 12 3 - - - 4 - 4 5 - - - 7 - 7 = = = = 1 - 1 1 - - - 2 - 2 2 - ~ - 2 5 5 = 1 - 2 - 5 5 a = = 1 _ 2 2 LS 4 - 4 1 13 14 = 2 = 2 - 6 6 = 5 1 6 - 16 16 - 5 3 2 1 14 15 = 5 1 3 - 14 14 = 11" 6 2 1 23 24 - 9 6 3 - 20 20 = 10 A 2 1 22. 23 = 7 7 1 - 19 19 2 3 6 1 - 10 10 = 4 6 2 - 13 13 = 5 6 = = 112 12 = 6 3 = 1 12 1h} - 3} 5 - - 8 8 2 = 1 - 1 1 2 2 = 2 = = 3 3 = 1 3 - - 5 5 = = 2 = = 2 2 = = = = - 3 3 = = 2 - - 4 “4 = = 1 = 3 3 By = 2: be = 1 1 = = 1 - - 1 1 Fe = = = = 1 1 pee ee ee ee a EEE EE EEE eee 45 81 69 o2 80 238 318 Total 31 Table 22. Number and length of leptocephali of Anguilla anguilla collected at different stations during September 1962 and 1964, east and west of longitude 50°W (see Tables 16 and 17 for complete list of stations). Range 10 western stations 15 eastern stations Total (25 stations) (mm) N % N % N % 40-4 46* 57.4 2 0.8 48* We 45-9 26 32.5 - ~ 26 822 50-4 a 3.8 23 eZ 26 8.2 55-9 2 25 73 30.7 75 23.6 60-4 1 1.3 84 3553 85 2627 65-9 2 229 36 15). 1 38 Hef 70-4 - - 14 5.9 14 4.4 75-9 - - 6 275 6 19 Total 80 238 318 Mean 45.16 61.02 5708 Range 38-68 43-79 38-79 * including one — 38 mm long Table 23. Number and length of leptocephali of Anguilla anguilla obtained in the western North Atlantic from October to December, 1964-1968 (see Table 17 for complete list of stations). Length October, 1964 November, 1968 December, 1968 Grand total (mm) 3 stations 3 stations RHB 1723 RHB 1727 Total October-December (8 stations) 34 - - 1 - 1 1 5 "3 = 2 - 2 2 6 = - 2 = 3 3 7 - 1 5 - 5 6 8 - 1 8 - 8 9 9 - - 8 - 8 8 40 - 2 5 2 8 10 i = 2 5 - 5 7 2 ~ 3 3 2 5 8 3 = - 1 1 3 3 4 - 1 - 2 5 6 5 - 2 1 3 6 8 6 = = = = = = 7 = - - - 1 1 51 2 = = = = 2 53 1 = = = = L 55 1 - = = z 1 59 1 - = - - 1 Total 5 12 41 10 60 WT 33 Table 24.Number and length of Anguilla rostrata leptocephali collected monthly in the western North Atlantic between 1933-1968. Month Length in mm 12-19 20-29 30-39 40-49 50-59 60-69 Total N % N % N % N % N % N % N % January - - - . - 1 100 - - - - 1 0.1 February - - - = - - 2 100 - - - - 2 0.2 March DO bah - - - - | 9% - - - - 3 0.3 May - - 4 444 5556 - - - - - - 9 Let June 2 0.4 94 19.8 2976277 UY Aer 2 0.4 - - 474 60.0 August - - - = - = 36. 3729 57 60.0 D 95 12:0 September = - - - - - 4 2.4 114 67.5 By) 10) 77 169 21.4 October = - - - i O20 - - 4 40.0 50.0 10 les November - - - - - - - - SOS 1 6.3 16 222 December - - - = - = 4 364 6 54.5 1 9.1 11 1.4 Grand total 4 0.5 98 24 303 38.3 762 198 25:0 60 7.6 790 100.0 Table 25. Number and length of leptocephali of Anguilla anguilla collected monthly in the western North Atlantic between 1933 and 1968. Month Length in mm 14-19 20-29 30-39 40-49 50-59 60-69 70-79 Total N % N % N % N % N % N % N % N % January - - - - 1 7/7} 11 84.6 1 Cdl - = - - Us 3.0 February = - - - 2 100.0 - - - - . - - - 2 0.5 March - - - - 2 50.0 225010 - - - - - - 4 0.9 May 4 80.0 - - - - 150200 - - - - - - 5 122. June = - 15516 2) 33:3 STE - - - - - - 9 21 August - - - = 2 40:0 1 92070 12.050 152010 - - 5 1.2 September - - = - 1 0.3 7823 /0OMNTOINNSTEEMI2S 587 20 6.2 318 73.2 October - - - = - - - - 5 100.0 - - = - 5 122 November - - - - 2MGN7 10 83.3 - - - - - 12 2.8 December = - - - 27 45.0 gs GEO - - = = = - 60 13.9 Grand total 4 0.9 5 2 40 PSP RS OS OS 2 5 ONI24 816 20 4.6 433 100.0 34 00! 002 oOV os0+ 1S0r oO o0C 600} 800! soo \ Pooh (696 L ‘/e 29 SNyDeg Jaye PalJIPOW) 124998 - 1240120 - O ‘18q -wajdas - S ‘aunr - f ‘U91eW pue Aseniqa4 - 4 :SMO]|O} Se payeu -Bisap ase syjuotu JUdJa}HIP eur 107 Sease Hunoajjoo jediounud ayy ‘Apnis Juasa1d ay} 10} pauie]qo aiam eydasojda| e///n6ut YdIYyM JO awoOs je ‘SuONeIs Huljdajjoo gHH 2e} ay) jo uONISOg “| 21nBi4 We 1 oOI 692) 0221 +080 cas, 9 #O2io O20 ae 0556 & 7 508 oz one oz me ives 0€56 up 19 oz 20210 CONG s+ ë açer seer eae) 9080 22200 Be a col SF s9eh “pi2) = OH 16210 b92i EUR © ovo çsçei pe sa Ler17:] 0:66 A ao 009521 zz 92h 2080 0021 o i) Ha DTIESN ‘o ," 2S2pES2+ Sem TA - 8080 DE 09. fe | ie 6080 o es 0 16 T4 0180 Le 80 OI£io SO +20: % 60gr7 2° son ed) gost Tax va Log 90€ ÉEMOTS °0t o ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° o ° 0000000000000000 °08 °00! 35 ‘adeys Apog mouseu ‘Jejiluis Jayje1 e aAeY ljeydasojdal] IV ‘SN G96L BL eUNL UO onUeNY YON UI8ISM 8} UI GILL uonels gHH 12 U2YE1 ‘WwW GE 0] WwW |Z Wo YyHusa ul Bulbues ejensos eyinbuy Jo 1eudeso1de]| Q/ jo Bunsisuos jney y ‘z einBi4 36 (Zt6L ‘uasue dsar sayye) sjassan pooyq [P91112A 2814] Jo uorIsod au} pue saiawoAw jeueysod pue -a1d ay} uaamjaq uoNeiedas ay) Bul -mous Snjeuydesoida] ey//nBuy ue jo Buimeip onewauos y ‘€ e1nB14 f—— Sasawohw }DuD}Soy EN CHAT TR VONT Sasawohw )}DUDasg > \\\\ us \(eraty yyBuay psppunys 37 ‘ydeiBbojoud eu} JO WOI0q ay} je UsWIDads au} Apejnared ‘adeys ul MOoseU Jaujes ase ey/inBue ajiym daap 1euje1 si e7e/2S0/ jo adeys Apog au, ‘A'N +961 ‘9 1eque]des UO OHUeNY YON U191S8M ay) Ul LLOL uoneils GHy ye U9YE] WwW /G 0} WW |p Woy BuiBue: eyinbue ‘Vy J0 Heydeso]de] ¢ pue WwW Qg 0} Ww pp Woy YyiGua; ui BuiBues ejensos eyjinBbuy jo jeudenode] 91 jo Bunsisuoo jney y “pf eunbi4 38 SYLLOGEUS TITLES PUBLISHED TO DATE No. 1 No. 2 No. 3 No. 5 No. 6 McAllister, D.E., et a/. A BATCH PROCESS COMPUTER INFORMATION RETRIEVAL AND CATALOGUING SYSTEM IN THE FISH COLLECTION, NATIONAL MUSEUM OF NATURAL SCIENCES. Shchepanek, M.J. BOTANICAL INVESTIGATION OF THE OTISH MOUNTAINS, QUEBEC Shih, Chang-tai A PRELIMINARY SURVEY OF INVERTEBRATE ZOOLOGISTS AND THEIR PRESENT ACTIVITIES IN CANADA RÉPERTOIRE PROVISOIRE DES ZOOLOGISTES DES INVERTEBRES ET DES TRAVAUX QU'ILS POURSUIVENT PRÉSENTEMENT AU CANADA Faber, Daniel J., Ed. A HIGH SCHOOL FIELD AND LABORATORY STUDY OF LAC LAPECHE IN GATINEAU PARK, QUEBEC, DURING MARCH, 1972 Gorham, Stanley W., and Don E. McAllister THE SHORTNOSE STURGEON, ACIPENSER BREVIROSTRUM, IN THE SAINT JOHN RIVER, NEW BRUNSWICK, CANADA, A RARE AND POSSIBLY ENDANGERED SPECIES Vladykov, Vadim D., and Herratt March DISTRIBUTION OF LEPTOCEPHALI OF THE TWO SPECIES OF ANGUILLA IN THE WESTERN NORTH ATLANTIC, BASED ON COLLECTIONS MADE BETWEEN 1933 AND 1968