■596; XFWS-A 596 1-12 (1970) U.S. Fish Wildl. Serv. Spec. Sci. Rep. Fish. Fecundity, Multiple Spawning, and Description of the Gonads in Sebastodes SPECIAL SCIENTIFIC REPORT-FISHERIES Na 596 SPECIAL SCIENTIFIC REPORT-FISHERIES EDITORIAL STAFF Leslie W. Scattergood, Editor Mary S. Fukuyama, Associate Editor PUBLICATION BOARD John A. Guinan John I. Hodges Edward A. Schaefers Harvey Hutchings Parker S. Trefethen John M. Patton, Jr. Robert C. Wilson Leslie W. Scattergood, Chairman Special Scientific Report — Fisheries are preliminary or progress reports and reports on scientific investigations of restricted scope. Established as Special Scientific Report in 1940, nos. 1 to 67 were issued from that date to 1949, when the new series. Special Scientific Report-- Fisheries, with new serial numbering, was started. Special Scientific Report— Fisheries are distributed free to libraries, re- search institutions, State agencies, and scientists. UNITED STATES DEPARTMENT OF THE INTERIOR Walter J. Hickel, Secretary Leslie L. Glasgow, Assistant Secretary for Fish and Wildlife, Parks, and Marine Resources Charles H. Meacham, Commissioner, U.S. FISH AND WILDLIFE SERVICE Philip M. Roedel, Director, Bureau of Commercial Fisheries Fecundity, Multiple Spawning, and Description of the Gonads in Sebastodes By JOHN S. MacGREGOR United States Fish and Wildlife Service Special Scientific Report--Fisheries No. 596 Washington, D.C. March 1970 CONTENTS Page Introduction 1 Materials and methods i Spawning season 4 Description of the ovaries and eggs 5 Variations among ovaries of different species of Sebastodes 5 The live-bearing trait in fishes 8 Eggs of oviparous scorpaenids 8 Artifactual and natural aberrations among eggs in Sebastodes 9 Description of the testes 10 Conclusions 1 1 Literature cited 12 111 Fecundity, Multiple Spawning, and Description of the Gonads in Sebastodes By JOHN S. MacGREGOR, Fishery Biologist Bureau of Commercial Fisheries Fishery-Oceanography Center La Jolla, California 92037 ABSTRACT More than 50 species of Sebastodes, an ovoviviparous genus of scorpaenid fishes, occur off the California coast. In the ovaries of nine species examined, evidence of two spawnings per spawning season was found in three (S^. ovalis, S. constellatus, S. paucispinis) but not in the other six (S. carnatus, S, rosaceus, ^, serriceps, S. serranoides, S. atrovirens, S. ruberrimus). Two spawnings were indicated by either (1) small numbers of advanced larvae entrapped in the ovaries and associated with full complements of developing eggs or early ennbryos or (2) a secondary group of developing eggs along with about equal numbers of ad. vanced embryos. The relative number of eggs or embryos was lower in the three species that gave evidence of two spawnings (162 eggs or embryos per gram of fish) than in the other six species (280 eggs or embryos per gram of fish). INTRODUCTION The rockfishes of the genus Sebastodes (family Scorpaenidae) support an important commercial and sport fishery along the coast of California, where more than 50 species occur (Phillips, 1964). These fishes are of special biological interest because they are ovoviviparous. Together with 18 species of viviparous Embiotocidae they contribute to a marine fauna that probably contains a higher proportion of species of live-bearing fishes than that in any other similar area in the world. Estimating the seasonal fecundity of a fish species presents two prinnary problenns. The first and easier problem is to determine the numbers and size distribution of yolked eggs in the ovary. The second and more difficult is to determine how many times the fish spawns during the spawning season. Seasonal spawning in relation to the size distribution of yolked eggs within the ovaries may follow one of four patterns: (1) a bimodal (or multimodal) distribution of eggs in which spawning of the nnore advanced group is fol- lowed by development and spawning of one or more additional groups derived from the sec- ondary group; (2) a bimodal distribution of eggs in which the most advanced group is spawned and resorption of the secondary group follows; (3) a unimodal distribution of eggs constituting the only spawning for that season; (4) a unimodal group of eggs which is spawned either shortly before or shortly after a secondary group is developed from the reserve of nonyolked egg cells. In this last situation, if a bimodal condition is present, it is present only when the advanced eggs are ripe or nearly ripe-- unlike the more usual bimodal condition that is present from the earliest differentiation by size of the ad- vanced group. In addition to the above four patterns, fish may develop eggs that are resorbed without spawning if the necessary environment or other spawning stimuli are absent. Often where multiple spawning is sus- pected, evidence of previous spawning seems to disappear within a relatively short time. Fishes of the genus Sebastodes offer a unique opportunity to investigate some aspects of multiple spawning because they are live-bear- ers that have eggs of a type similar to the pe- lagic, nonadhesive eggs of many marine fishes. MATERIALS AND METHODS The rockfish examined for this paper were taken by the BCF (Bureau of Commer- cial Fisheries) research vessel. Black Douglas, on: January 20, 1961, at Forty- mile Bank, about 40 nautical miles west of San Diego, Calif.; March 3, 1961, at the Rockpile, about 20 nautical miles south of San Diego; and on April 11, 1961, at Tanner and Cortes Banks about 100 nautical miles west of San Diego. R.H. Rosenblatt and C. C. Tuthill of Scripps Institution of Oceanography identified the rockfish taken January 20, and F.H. Berry of the then BCF California Current Resources Laboratory, La Jolla, Calif., identified those ■collected on March 3 and April 11. The larger species of rockfish were meas- ured and weighed fresh, and only the ovaries were preserved in formalin. The smaller species were preserved in formalin at cap- ture. They were measured and weighed, and the gonads removed the following week at the laboratory. After the ovaries were weighed and exa- mined, the distributions of egg diameters were deternnined by the technique described by MacGregor (1957) for eggs of the Pacific sardine (Sardinops caerulea). Embryos were staged according to Ahlstrom's (1943) cri- teria for the Pacific sardine with the follow- ing exception: because rockfish embryos are more advanced than sardines at hatching, stage X was considered as extending from the end of Ahlstrom's stage IX to the begin- ning of eye-pigment formation, and stage XI from the beginning of eye-pign-ient formation to hatching. The numbers of eggs or ennbryos in each pair of ovaries were estimated by counting a weighed sample of the ovary under a binocular microscope and adjusting the count to the total ovary weight. Tabular data on the female rockfish are presented as follows: Forty-mile Bank, table 1; Rockpile, table 2; Tanner and Cortes Banks, table 3, Additional data from the literature are compared to this study in table 4. Only the length and maturity data are available for some of the fish listed in table 2 that were used for physiological studies. Table 1. — Data on eggs and embryos In the ovaries of female rockfish taken at Forty-mile Bank, January 20, 1961 Female rockfish ' Ovaries Eggs Embryos Embryos Standard length Total length Weight Weight Percentage of fish weight Number Maximum diameter Number Stage or eggs per gram of fish 1^. Jfa. Kg. G. Percent Number Nta. Number Number Number Sebastodes paucisplnls 590 695 3.5 W8.0 4.2 731,811 0.72 — 209 495 590 2.15 2A6.0 11.4 — — 388,399 XI 181 457 552 1.7 235.0 13.8 — — 482,440 III-IV 234 455 545 1.7 139.5 11.1 — — 361,062 IX 212 460 545 1.55 103.0 6.6 — — 186,001 V 120 460 545 1.5 112.5 7.5 — — 213,241 IV 142 455 540 1.5 47.84 3.2 205,130 0.66 — ~ 137 435 520 1.45 222.0 15.3 — — 512,497 II 353 450 540 1.4 29.22 2.1 335,765 0.54 — -- 240 440 530 1.4 41.90 3.0 250,866 0.62 — _ 179 435 520 1.4 200.0 14.3 — — 425,038 VI 304 430 510 1.3 174.0 13.4 — — 341,545 X 263 390 437 1.1 88.90 8.1 ~ ~ 127,449 XI 116 Sebastodes ruberrimus 530 615 5.0 142.0 2.8 1,355,838 0.56 271 455 530 3.2 82.25 2.6 1,095,786 0.52 — — 324 Sebastodes derranoides 372 450 1.35 256.0 19.0 1 ~ 445,623 X 330 405 1.2 42.54 Sebastodes ovalls 0.78 335 3.5 132,077 110 335 400 1.1 173.4 15.8 121,398 0.66 113,515 XI 110-108 320 384 0.9 40.79 4.5 115,458 0.86 — ~ 128 305 365 0.8 47.39 6.0 — — 70,614 X 38 292 345 0.75 42.01 5.6 114,151 0.96 ~ ~ 152 Sebastodes roeaceus 196 235 0.240 6.99 2.9 66,761 0.62 — 278 191 229 0.198 6.94 3.5 62,992 0.70 ~ ~ 318 Table 2.— Data on female rookflBh taken at the RDCkpile, March 3, 1961 Egg Embryo Embryos Gonad Specie.- cr Sebastodes Stand- ard length Total length Weight Gonad Weight or eggs per gram weight Number Maximum Number Stage as a percent- age diameter of fish of fish weight m. Mm. Kg- G^ Number m. Number Number Number Percent S. oarhatus 216 259 0.355 42.894 — — 95,704 X 270 12.1 Eb. 217 265 0.339 19,491 104,101 0.86 _.. _„ 307 5.7 Do. 190 231 0.281 30,363 — — 67,982 IV-V 242 10.8 Do. 185 226 0.251 6.386 44,118 0.86 __ 176 2.5 Do. 217 262 0.86 Do. 215 259 — XI Do. 195 235 — — 0.86 __ Do. 137 227 — — II Do. 177 216 0.202 0.262 — ~ — ~ — 0.13 S. serrlceps 237 285 0.362 21.452 69,599 1.00 _ 192 5.9 Do. 225 268 0.52 _„ Do. 2W 262 _ 0.48 .._ __ __ Do. 196 238 0.250 ~ — 0.70 ~ — ~ — S. atrovlrens 263 318 0.416 10.888 143,156 0.62 __ „ 344 2.6 Do. 251 311 0.454 20.251 182,890 0.76 403 4.5 Do. 227 277 0.299 2.010 0.42 0.67 Do. 215 267 0.299 3.117 0.50 __ __ 1.04 Do. 2er II Number 151 Percent S. oonstellatuB 120,824 5.8 Do 244 291 0.449 41.74 — — 78,967 XI 176 9.3 Do. 257 305 0.554 62.88 — — 105,510 X 190 11.3 Do. 2W 290 0.370 42.92 — — 71,928 XI 194 11.6 Do. 225 268 0.391 9.68 34,207 0.82 ~ — 87 2.5 S. roeaeeuB 193 232 0.196 15.87 — — 44,288 IX 226 8.1 Do. 189 224 0.163 2.76 37,044 0.56 — — 227 1.7 Do. 181 220 0.184 7.26 — — 26,344 Ill U3 3.9 Do. 169 203 0.142 9.77 — 33,371 X 235 6.9 Do. 150 184 0.119 7.87 ~ 24,822 X 209 6.6 Table <+. — Estimates of egg production of 20 species of Sebastodes Species of Weight Ysggs per gram of fiKVi Sebastodes Fish range References Mean Range Number M- Number Number S. ovalis 5 0.75-1.2 116 88=152 Present paper S. .iordani 10 0.046-0.275 131 83-182 Phillips, 1964 S. auriculatus 35 0.510-2.290 139 95-176 DeLacy, Hitz & Dryfoos, 1964 5. goodei 23 0.349-2.504 151 71-285 Phillips, 1964 S. constellatus 5 0.391-0.800 160 87-194 Present paper S. crameri 12 0.617-3.062 165 51-237 Phillips, 1964 S. caurinus 33 0.283-2.608 183 38-301 Delacy et al., 1964 S. serriceps 1 0.362 192 — Present paper S. paucispinis 13 1.1 -3.5 211 116-353 Present paper S. pinniger 1 2.722 220 — Fraser, 1923 S. rosaceus 7 0.119-0.240 234 143-318 Present paper S. camatus I. 0.251-0.355 249 176-307 Present paper S. entomelas 20 0.431-2.177 288 120-600 Phillips, 1964 S. flavidus 15 0.376-2.227 298 94-506 Phillips, 1964 S. ruberrimus 2 3.2 -5.0 300 271-324 Present paper S. paucispinis 24 0.558-4.998 304 36-537 Phillips, 1964 S. ruberrimus 1 8.845 305 -- Clemens and Wilby, 1949 S. dlploproa 15 0.118-0.776 312 112-502 Phillips, 1964 S. serranoides 1 1.35 330 — Present paper S. miniatus 12 0.517-2.631 347 122-618 Phillips, 1964 S. atrovirens 2 0.416-0.454 374 344-403 Present paper S. saxicola 13 0.068-0.490 415 169-931 Phillips, 1964 S. pinniger 10 1.619-4.441 470 161-815 Phillips, 1964 SPAWNING SEASON Some information on the spawning season can be had from data on the collection of Sebastodes larvae in plankton net hauls (table 5) in the survey area of CalCOFI (California Cooperative Oceanic Fisheries Investiga- tions)--Oregon to the southern tip of Baja California-.for 1950-57 (Ahlstrom, 1952, 1953, 1954, 1958,1959; Ahlstrom and Kramer, 1955, 1956, 1957). The species of larvae were not separated; as a group they constituted 7.6 percent of all larvae taken (average for 1955, 1956, and 1957). Their numbers were ex- ceeded only by the larvae of northern anchovy (Engraulis mordax) and Pacific hake (Mer- luccius productus). In 1950-52, the number of Sebastodes larvae per haul averaged 13.9 and the peak of larval abundance was in April (2 years) and March (1 year). In the following 5 years Sebastodes larvae per haul averaged 25.1 and the peak of larval abun- dance came earlier, in February (4 years) and January (1 year). Rockfish clearly tend to spawn in winter; during the 8 years, the first 4 months of the year accounted for 68 percent of all Sebastodes larvae taken. Other studies have also indicated that rock- fish tend to spawn primarily in winter. Fitch (1958) recorded the hatching season of Se- bastodes paucispinis as December through April and of S. miniatus and S. serrnoides as December through March. Wales (1952) gave the hatching season of S. mystinus as Novem- ber through March, Clemens and Wilby (1949: 206), referring to young Sebastodes along the Canadian Pacific coast, stated, "These are less than 1/2 inch in length and are produced in large numbers during the sum- mer months," Table 5.— Rockfish spawning by months as Indicated by aebaatodes larvae taken In plankton net tows at CalCOFI station off of the coast of California and Baja California, 1950-57 1950-52 1953-57 1950-57 fcbnth Stations Larvae collected Percentage^ of total spawning Stations Larvae collected Percent- age^ of total spawning Stations Larvae collected Percentage^ Total Per haul Total Per haul Total Per haul of total spawning January February March April May June July August September October November December 218 321 402 421 443 483 423 322 309 175 180 64 Number 4,161 6,196 8,437 12,527 5,822 5,840 3,931 2,171 646 734 1,120 510 Number 19.1 19.3 21.0 30.0 13.1 12.1 9.3 6.7 2.1 4.2 5.2 8.0 Percent 12.6 12.8 13.9 19.9 8.7 8.0 6.2 4.4 1.4 2.8 4.1 5.3 511 600 729 923 1,054 1,063 854 313 158 470 147 368 Number 22,305 50,539 32,436 26,721 15,494 10,521 8,525 2,242 559 2,827 2,595 5,914 Number 43.6 84.2 44.5 29.0 14.7 9.9 10.0 7.2 4.2 6.0 17.7 16.1 Percent 15.2 29.3 15.5 10.1 5.1 3.4 3.5 2.5 1.5 2.1 6.2 5.5 729 921 1,131 1,344 1,497 1,546 1,277 635 467 645 327 432 Number 26,466 56,735 40,873 39,348 21,316 16,361 12,457 4,413 1,305 3,561 3,715 6,424 Number 36.3 61.6 36.1 29.3 U.2 10.6 9.8 6.9 2.8 5.5 11.4 15.2 Percent 15.1 25.7 15.1 12.2 5.9 4.4 4.1 2.9 1.2 2.3 4.3 6.3 Total or average 3,761 52. 19 J 13.9 -- 7,190 180,770 25.1 — 10,951 232,974 21.3 — ■^Percent spawning is weighted to the number of stations in that month. DESCRIPTION OF THE OVARIES AND EGGS The ovaries are sac- shaped, of about equal size, and slightly joined posteriorly. Those containing yolked eggs or early embryos are yellow, except that some ovaries of Sebastodes paucispinis tend to be cream-colored. Ovaries that contain late embryos (stage XI) become dark gray owing to the formation of larval pigment, especially in the eyes. Variations Among Ovaries of Different Species of Sebastodes The ovaries of three species--S. paucis- pinis, S. ovalis, and S. constellatus-- contained remains of larvae from the previous spawn- ing. Most ovaries of S. paucispinis and S. ovalis that contained embryos or xinfertilized eggs also had dark blotches or spots just under the tissue of the ovarian envelope. In at least sonne specimens this dark material was composed of pigment spots of advanced larvae from a previous spawning that had failed to escape from the ovary upon hatching. The yolk sacs of airthese larvae were almost completely absorbed, and the larvae were developed beyond the stage at which they are normally released. In some ovaries the lar- vae were intact and in good condition (fig. 1); in others they were disintegrating; and in still others only the pigmented lenses of the eyes remained (fig. 2), Advanced larvae, more or less intact, from the previous spawning were found in 6 of the 13 ^. paucispinis studies and were associated with early embryos and unfertilized eggs. Four contained questionable larval remnants, and no traces of larvae were found in the re- maining three; embryos were more advanced in these seven ovaries than in the other six. Four of five S. ovalis contained larvae from the previous spawning with the developing eggs or embryos. The ovaries of the fifth contained a full complement of embryos on the verge of hatching and a group of unfer- tilized eggs near maturity. The estimated number of embryos was 118,000, and the number of eggs 121,000. Figure 3 shows stage XI embryos and unfertilized eggs from this fish. Of five S. constellatus taken on April 11, three contained stage X and XI embryos and a secondary group of unfertilized yolked eggs about equal in numbers to the primary groups of eggs containing embryos. Diameters of these smaller eggs were 0,20 to 0,46 mm. Neither of the remaining two specimens had secondary groups of yolked eggs, but one that contained stage II embryos also had black pigment spots that may have been larval remnants within the ovary, and one containing advanced unfertilized eggs also contained one advanced larva, in good condition, from a former spawning. No evidence of previous spawning appeared in the ovaries of the three specimens that contained the secondary modes of eggs. None of the other species of Sebastodes examined contained larvae such as those found in the above three species. The ovaries of all species had small eggs less than 0.20 mm. in diameter, without yolks. The ovaries of two S. mystinis, one 272-mm. S. constellatus taken March 3, and one--the smallest--S, carnatus contained only this type of egg. IT Figure 1. — Sebastodes ova Us — nearly ripe eggs and entrapped larva from the previous spawning as seen through the tissue enveloping the ovary. ^ Figure 2. — Sebastodes ovalls — stage X embryos and pigmented lenses of the eyes of entrapped larvae from the previous spawning. Figure 3. — Sebastodes ovalls — stage XI embryos and unfertilized eggs of the subsequent spawning batch. These fish were probably immature, although it is possible that the ovaries were in a resting condition rather than immature. The other fish contained a single group of either yolked eggs or embryos (except for the one S. ovalis and three S. constellatus mentioned above, which contained both), A few fish that had yolked eggs also con- tained a secondary group of yolked eggs smaller than the main group of developing eggs. (An example of this size distribution of a group of such eggs--0.20 to 0.44 mm. diameter--is shown in the frequency distribu- tion plotted in figure 5A.) These eggs, how- ever, were not considered as part of a batch to be spawned. Howard and Landa (1958), who found similar distributions of eggs in the anchoveta (Cetengraulis nnysticetus), con- cluded that these smaller eggs were not spawned. To be considered as a possible subsequent spawning group, the number of these smaller eggs should about equal or exceed that of the more advanced group. This condition is frequently found in other species of fish. The number of these second- ary eggs did not exceed that of the primary group in any of the Sebastodes specimens examined (except for the S. ovalis and S. constellatus specimens containing about equal numbers of stage X or XI embryos and rather well- developed eggs); and in practically all fish the small eggs equalled only a small fraction of the primary group or were absent from the sample examined. The above findings indicate that at least some individuals of S. paucispinis. S. ovalis, and S. contellatus spawn two batches of larvae a season; these three species generally pro- duced distinctly smaller numbers of eggs per batch than the species that appear to spawn only once per season. The average relative fecundities (eggs or embryos per gram of fish) of the three species were as follows: S. ovalis, 116; S constellatus. 160; and S. paucispinis, 211 (mean, 162). For six species that showed no evidence of more than one spawning the averages were as follows: S. serriceps (only one specimen available), 192; S. rosaceus. 234; ^. carnatus, 249; §. ruber- rimus, 300; S. serranoides, 330; and S. atrovirens, 374 (mean, 280). The mean relative fecundity of S. ovalis and of the five S. constellatus collected on April 11, all of which showed evidence of two spawnings, was 138 or about half of the mean of the other six species. In S. paucis- pinis, in w^hich some specimens gave evidence of two spawnings and some did not, the relative fecundity was about midway between the two groups. No relation was detected within the species S. paucispinis, between evidence of two spawnings and relative fecun- dity. The group of six specimens that showed evidence of two spawnings and the group of three that did not each had average relative fecundities of 219; the four questionable spe- imens had an average relative fectmdity of 192. The association of secondary groups of unfertilized yolked eggs with only stage X and XI embryos indicates that the secondary group does not begin to develop until the pri- mary group is much advanced. I have also found this condition in the oviparous species, Vinciguerria lucetia, in the developing ovaries of which only one group of yolked developing ova is present unless this group is almost ripe; then, a secondary group of smaller yolked ova, in numbers about equal to the primary group, may often be found. In many species of fish the secondary group of yolked ova is present throughout most of the devel- opment of the primary group but shows little growth, especially when measured by volume rather than dianneter, until the primary group is almost ripe or has been spawned. In the oviparous species, Cololabis saira, the sec- ondary group of yolked ova may out-number the primary group 10 or 20 times. From this numerous secondary group a second spawning batch about equal in number to the primary group will develop, but only when the primary group is ripe or nearly ripe. In some species of fishes a secondary group of yolked eggs may be resorbed after the spawning of the primary group; in others the secondary group may furnish one or more subsequent spawning batches; and in still others either condition may prevail depending on age, size, or condition of the fish or the environment. The evidence of entrapped larvae in asso- ciation with fertilized eggs in the ovaries of the three species of Sebastodes is almost conclusive proof of at least two spawnings per season in these species. The absence of entrapped larvae does not necessarily prove that the other species do not spawn more than once, although it offers a strong indica- tion. A greater time interval between spawn- ings in some species would allow more time for the disintegration of larvae, and the absence of a developing group of secondary eggs at hatching time might allow all larvae to escape from the less crowded ovary. None of the authors listed in table 4 men- tioned evidence of multiple spawning in the species they examined, although a few of the species seem to have rather low relative fecundities. In the present study, with the ex- ception of S. ovalis, S. constellatus, and some S. paucispinis (table 1, 2, and 3), the relative fecundity approximates the range of 200 to 400 eggs per gram of fish typical of many marine fishes of similar size that spawn nonadhesive, pelagic eggs. The fertil- ized Sebastodes egg more closely resembles such eggs than do those of any other live- bearing species. The Live -Bearing Trait in Fishes A number of families of fishes other than the Scorpaenidae include species that bear living young. Eigenmann (1894: 404) stated: At least two types of viviparity may be distinguished in fishes: first, those In which the yolk furnishes all the Intraovarlan food (Poecllla, Gambusla, Scorpae- nidae); and second, those in which the greater part of the food is furnished by the ovary (Biennis, Anableps, and Emblotocldae). In the first type the number of young is usually not less than in related oviparous forms, while the number of young in the second is always greatly reduced. In addition to the Poecilidae, Scorpaenidae, Blennidae, and Embiotocidae mentioned by Eigemann, the live-bearing trait is found in the Hemiramphidae and Zoarcidae. In the Hemiramphidae, generally saltwater forms such as Hemiramphus and Hyporhamphus are oviparous but generally fresh-water forms such as Zenarchopterus and Dermogenys are live-bearing (Smith, 1945). In the Zoracidae, Zorces viviparus of the eastern North Atlan- tic is viviparous, whereas Zoarces anguillaris of the western North Atlantic spawns large demersal adhesive eggs (Bigelow and Schroeder, 1953). Eggs of Oviparous Scorpaenids The available data indicate that the ovipar- ous scorpaenids are pelagic spawners. Okada (1955) reported that the scorpaenid, Hydrodytes rubripinnis, spawns pelagic eggs 0.8 to 0.9 nann. in diameter in July and August. Fitch (1958), who reported that Scorpaena guttata spawns from April through August, described a modification unique to this genus. "The eggs are imbedded in the gelatinous walls of hallow, pear-shaped, egg-balloons. The paired egg-balloons, each 5 to 10 inches long are joined at their small ends. The walls of these 'balloons' are about one-tenth inch thick, transparent or greenish in color and contain a single layer of eggs. The eggs are about one-twentieth inch each in diameter. The 'balloons' are spawned at the bottom of the sea and rise rapidly to the surface. The eggs hatch at the surface within 5 days." Artifactual and Natural Aberrations Among Eggs in Sebastodes Certain embryonic stages were consider- ably distorted by the formalin used in preser- vation. Many eggs containing embryonic stages II through V were larger than others from the same ovary, although the embryos in the size groups of eggs appeared identical (table 6, fig. 4). This condition appeared to be caused by the rupturing of the yolk mem- brane, owing to the osmotic effects of the preservative, whereas the egg membrane re- mained intact. From 25 to 39 percent of the Table 6. — Sebastodes paualsplnls — embryonic stage, egg diameter, and embryos per gram of ovary 20 15 10 >- 5 o z UJ S 0 q: ^ 20 10 Embryonic stage Median egg diameter Embryos Intact yoUts Ruptured yolks per gram of ovary Number Mm. Mm. Number n 0.7S 0.90 2.309 m-iv .80 .98 2.053 rv .78 .96 1.880 V .78 1.04 1.806 VI .78 — 2.125 K .78 — 1.905 X .82 — 1.963 XI — — 1.579 XI - — 1,434 (A) STAGES n-2 oLA 0.70 080 Q90 1.00 1.10 1.20 EGG DIAMETER (EXCLUDING EMBRYO) IN MILLIMETERS Figure 4. — Diameter frequencies of fertilized eggs from the ovaries of Sebastodes paucisplnls showing the effect of formalin preservation before (A) and after (B) blastopore closure. stage II to V eggs were affected in fish con- taining these stages. None of the eggs of stages VI to XI were affected. It may be relevant that blastopore closure takes place at stage V, The greater fragility of early- stage eggs has been observed in other fish species (Ahlstrom and Ball, 1954). Another type of aberrant Sebastodes egg in ovaries containing embryos consisted of un- fertilized or undeveloped eggs of the same original batch as the developing embryos. These eggs contained a ruptured yolk mem- brane, had yolk material of uniform texture distributed within the egg membrane, had a normal oil globule, and were 1.20 to 1.84 mm. in dianneter..A pooled sample of embryos from several specimens of S. paucispinis contained 23,146 embryos and 14 (0.06 percent) unferti- lized or undeveloped eggs. These eggs were found in all species that contained embryos. Formalin may also cause swelling in ripe, unfertilized eggs. The diameters of intact, ripe, unfertilized eggs of most of the species, of Sebastodes averaged about 0.80 mm. Those of S. rosaceus were smaller- -average about 0.65 mm. The female S. serriceps contained a group of eggs that averaged 0.94 mm. and were 0.86 to 1.00 mm. in diameter- -the largest unfertilized eggs found in any of the specimens. Because no other comparable ma- terial for this species appeared in the collec- tions, the amount of possible swelling caused by preservation is not known. The diameters of the yolks of newly fertil- ized eggs and stage X embryos are closely similar (except as affected by preservation artifacts). One specimen of S. ovalis con- tained unfertilized eggs that averaged 0.91 mm. and were 0.80 to 0.96 mm. in diameter (fig. 5C). Most of these, except for a few 0.80 to 0.84 mm. in diameter, seemed to have ruptured yolk membranes, although this con- dition is difficult to detect because of the darkness of the yolk material in unfertilized eggs preserved in formalin. In another speci- men of S. ovalis containing stage X embryos the dianneter of the area enclosed by the yolk membrane averaged 0.80 mm. and ranged from 0.72 to 0.88 mm. (fig. 5A-D). To study the relation between yolk size of embryos, I determined the number of em- bryos per gram of ovary and measured the diameters of eggs for the various embryonic stages in the ovaries of the nine specimens of S. paucispinis. The thickness of the embryo was not included in the egg diameter, and as the perivitelline space is not developed, the "intact yolk" egg diameters are, for practical purposes, also yolk diameters. (Stage XI embryos, which have oval yolks, are difficult to measure accurately.) The volume enclosed by the yolk membrane did not decrease as the embryos increased in size (table 6). This fact is also shown by the decrease in em- bryos per gram of ovary as the embryos '0.20 030 0.40 050 0.60 O70 080 090 EGG DIAMETER (EXCLUDING EMBRYO IN STAGE X) IN MILLIMETERS Figure 5.— Diameter frequencies of eggs from the ovaries of Sebastodes ovalls— (A) unfenlllzed developing eggs before release of advanced embryos, (B) nearly ripe eggs with intact yolks, (C) ripe unfertilized eggs with ruptured yolks, (D) stage X embryos. develop. The increased size of eggs with ruptured yolk is reflected in the relatively low number of embryos per gram for stages II through V. Embryos per gram for these stages should probably be about 20 to 30 percent higher. Because fertilized rockfish eggs lack fol- licles, the yolk cannot be replenished. Water or other fluid probably replaces the yolk used by the developing embryo. Consequently the apparent volume of the unsegmented yolk remains the same while the weights of embryo and egg increase. The same condition appears to prevail in fish eggs that develop pelag- ically. The size of the yolk of the fertilized egg, therefore, indicates the size of the un- fertilized ripe egg which has no perivitelline space. DESCRIPTION OF THE TESTES The testes of male rockfish captured on January 20, 1961, were relatively much smaller than those of breeding males of most other species of fish. Although the testes are surrounded by the urinary bladder where they join the genital papilla (fig. 6), they apparently do not enter the bladder. In most specimens the bladder was filled with a clear fluid, but in one freshly caught speci- men of S. paucispinis the fluid was milky. Slight pFessure on the bladder caused the Figure 6.— Testes, blad- der, genital papilla, and part of the Intestine of Sebastodes serrlceps (scale in millimeters). GENITAL PAPILLA 10 fluid to be ejected through the genital papilla_ with considerable force. Eight specimens representing five species of Sebastodes, pre- served in fornnalin and examined in the labo- ratory, all appeared to have ripe testes; except for the one specimen of S. vexillaris; however, the bladders contained only clear fluid. In the S. vexillaris it appeared that Sonne testicular material having the con- sistency of putty had moved into the base of the bladder, and the bladder itself contained some whitish fluid. Although it is possible that the bladder functions to store, dilute, or ejaculate the sperm, it is probable that the conditions noted in the single specinnens of S. paucispinis and S. vexillaris were artifacts caused by the pressure changes undergone by the fish in being hauled to the surface. The relative gonad weight (weight of gonads as a percentage of weight of fish) for eight males was very low (table 7). The relative gonad weights of the females (tables 1, 2, and 3) were much higher and similar to other marine fishes in this size range. Among other species of fish the relative gonad weights of males and females are more closely simi- lar during the spawning season. The small size of the testes may be the result of partial spawning, as the spawning season was well advanced at the time of capture. Most of the females of the five species represented by the male contained unfertilized ova, however, as did most fe- males of the other species. Also, none of the many males examined at sea had noticeably enlarged gonads. The reduced size of the testes may be related to the presumed greater efficiency of internal fertilization. CONCLUSIONS Of nine species of Sebastodes examined three--S. ovalis, S. constellatus and S. paucispinis --showed evidence of two spawn- ings per year. Two lines of evidence were found: (1) small numbers of advanced larvae entrapped in the ovaries along with full com- plements of developing eggs or early em- bryos; (2) a secondary group of developing eggs in the ovaries with about equal numbers of advanced embryos. No evidence of two Table 7. — Data on length, weight, and weight of testes of rockfish Species of Sebastodes Standard length Total length Weight Weight of testes Weight of testes as percentage of fish weight Mm. Mm. G^ G^ Percent S. serriceps 215 251 311 0.456 0.15 S. atrovirens 250 306 426 1.099 .26 S. atrovirens 227 277 306 1.058 .35 S. vexillaris 285 345 612 1.521 .26 S. rosaceus 177 214 166 .178 .11 S. rosaceus 172 210 191 .170 .09 S. rosaceus 184 224 208 .198 .10 S. constellatus 240 429 285 .906 .32 £igenmann (1894) in his study of the vivi- parous embiotocid, Cymatogaster aggregatus, found that the two sexes were completely out of phase in the ripening of gonads. The males ripen in the spring, and copulation takes place at that time, following parturition. The sperm is stored by the females until they ripen the following fall. This situation prob- ably does not exist among the ovoviviparous species of Sebastodes. The eggs are fertilized when ripe and are merely retained in the ovaries until they hatch. spawnings was found in the ovaries of the other six species. The relative fecundity (number of eggs or embryos of a single spawning batch per gram of fish) averaged 162 for the three species that gave evidence of two spawn- ings and 280 for the six species that gave no evidence of two spawnings. In the species that spawn twice the development of the second spawning batch appears to be inhibited until the first batch is ferti- lized. 11 The weight of the eggs containing embryos increases as the ennbryos develop, even though the eggs are no longer connected to the ovarian tissue. The volume enclosed by the yolk membrane does not decrease as the ennbryo develops, apparently because the yolk used by the developing embryo is replaced by outside fluids. Preservation in fornnalin caused some swelling of ripe, unfertilized eggs and fertilized eggs in the stages of development preceding that of blastopore closure. Developing eggs that were not ripe and fertilized eggs after blasto- pore closure did not seem to be adversely af- fected. Swelling of eggs was accompanied by rupturing of the yolk mennbranes, although the egg membrane remained intact. The size of the ripe testes of male rock- fish, which are closely associated with the urinary bladder, are greatly reduced com- pared to those of most other species of fish. LITERATURE CITED AHLSTROM, ELBERT H. 1943. Studies on the Pacific pilchard or sardine (Sardinops caerulea) 4. --Influ- ence of temperature on the rate of development of pilchard eggs in nature. U.S. Fish Wildl. Serv., Spec. Sci. Rep. Fish. 23, 26 pp. 1952. Pilchard eggs and larvae and other fish larvae. Pacific coast, 1950. U.S. Fish Wildl, Serv., Spec. Sci. Rep. Fish. 80, 58 pp. 1953. Pilchard eggs and larvae and other fish larvae. Pacific coast, 1951. U.S. Fish Wildl. Serv., Spec. Sci. Rep. Fish. 102, 55 pp. 1954. Pacific sardine (pilchard) eggs and larvae and other fish larvae, Pacific coast 1952. U.S. Fish Wildl. Serv., Spec. Sci, Rep. Fish. 123, 76 pp. 1958. Sardine eggs and larvae and other fish larvae. Pacific coast, 1956. U.S. Fish Wildl, Serv. Spec. Sci. Rep. Fish. 251, 84 pp. 1959. Sardine eggs and larvae and other fish larvae. Pacific coast, 1957. U.S. Fish Wildl. Serv., Spec. Sci. Rep. Fish. 328. 99 pp. AHLSTROM, ELBERT H., and ORVILLE P. BALL, 1954. Description of eggs and larvae of jack mackerel (Trachurus symme- tricus) and distribution and abundance of larvae in 1950 and 1951. U.S. Fish Wildl. Serv., Fish. Bull. 56: 209-245. AHLSTROM, ELBERT H., and DAVID KRAMER. 1955. Pacific sardine (pilchard) eggs and larvae and other fish larvae. Pacific coast, 1953. U.S. Fish Wildl. Serv,, Spec. Sci. Rep. Fish. 155, 74 pp. AHLSTROM, ELBERT H., and DAVID KRAMER- - Continued 1956. Sardine eggs and larvae and other fish larvae. Pacific coast, 1954. U.S. Fish Wildl. Serv., Spec. Sci. Rep. Fish. 186, 79 pp. 1957. Sardine eggs and larvae and other fish larvae. Pacific coast, 1955. U.S. Fish Wildl. Serv., Spec. Sci. Rep. Fish. 224, 90 pp. BIGELOW, HENRY B., and WILLIAM C. SCHROEDER. 1953. Fishes of the Gulf of Maine. U.S. Fish Wildl. Serv., Fish. Bull. 74: 1-577. CLEMENS, W. A. and G. V. WILBY. 1949. Fishes of the Pacific coast of Canada. Fish. Res. Bd. Can. Bull. 58 (rev.), 368 pp. DELACY, ALLAN C, CHARLES R. HITZ, and ROBERT L. DRYFOOS. 1964. Maturation, gestation, and birth of rockfish (Sebastodes) from Washington and adjacent waters. Wash. Dep. Fish. Fish Res. Papers 2(3): 51-67. EIGENMANN, CARL H. 1894. On the viviparous fishes of the Pacific coast of North America. U.S. Fish Comm., Bull. 12:381-478. FITCH, JOHN E. 1958. Offshore fishes of California. Calif. Dep. Fish Game, Sacramento, Calif., 80 pp. FRASER, C. McLean. 1923. Ichthyological notes. Contrib. Can. Biol., N.S. 1: 285-295. HOWARD, GERALD V., and ANTONIO LANDA. 1958. A study of the age, growth, sexual maturity, and spawning of the anchoveta (Cetengraulis mysticetus) in the Gulf of Pananna. Inter-Amer. T r o p. Tuna Comm., Bull. 2:390-467. MacGREGOR, JOHN S. 1957. Fecundity of the Pacific sardine (Sardinops caerulea). U.S. Fish Wildl. Serv., Fish. Bull. 57: 427-449. OKADA, YAICHIRO. 1955. Fishes of Japan. Maruzen Co., Ltd., Tokyo, Japan, 434 pp. PHILLIPS, JULIUS B. 1957. A review of the rockfishes of Cali- fornia (family Scorpaenidae). Calif. Dep. Fish Game, Fish Bull. 104, 158 pp. 1964. Life history studies on ten species of rockfish (genus Sebastodes). Calif. Dep. Fish Game, Fish Bull. 126, 70 pp. SMITH. HUGH M. 1945. The fresh-water fishes of Siam, or Thailand. Bull. U.S. Nat. Mus. 188, 622 pp. WALES, JOSEPH H. 1952. Life history of the blue rockfish, Sebastodes nnystinus. Calif. Fish Game 38: 485-598. MS. #1595 12 G P 0 88 3'394 „MBL WHOI Library - Serials ' ' ir[i|iiiiiMiii-' As the Nation's principal conservation agency, the Depart- ment of the Interior has basic responsibilities for water, fish, wildlife, mineral, land, park, and recreational re- sources. 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