CalCOFI Reports, Vol. 11, 1967 - California Cooperative Oceanic ...

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62 CALIFORNIA COOPERATIVE OCEANIC FISHERIES INVESTIGATIOKSAi mmi mrn2 , tk- -c4 mrn4 1 IFIGURE 4.Lorval development of the anchovy (Engradis anchaifa). 1. Recently hatched larva; 2. 2X-dayr larva; 3. ddoys larva; 4. 10-doys larva(from Dz. de Ciechomski 1965).enabled her to obtain mature female anchovies (whichis impossible during other hours of the day), andto successfully achieve their artificial fecundation.The embryonic development of the anchovy is quiterapid. The most detailed drawings and descriptionsof the embryonic and larval development have beengiven in a paper by the present author, “Observacionessobre la reproduccion y desarrollo embrionarioy larval de la anchoita argentina (Engraulisanchoita) ” (Figures 3, 4, 5).The measurements of the eggs show rather pronouncedvariations: 1.15-1.55 mm for the major axisand 0.66-0.80 mm for the minor axis.In the earlier stages of development, the eggs floatvertically with their blastodiscs pointing downwards.As the enveloping of the yolk progresses, the
REPORTS VOLUIIE SI. 1 JULY 1963 TO 30 JUNE 1966 63orientation of the eggs becomes increasingly horizontal.At the stage of Kupffer's vesicle, the egg floatshorizontally, coming closer to the bottom during thelast stages of development.The hatching mechanism is always the same. Oncethis stage is reached, the membrane of the egg suffersa neat incision at a distance from the cephalic endequal to 6 the total length of the egg. After rupturehas taken place, the embryo frees itself from the eggmembrane in about 3 minutes. It should be emphasizedthat the rupture occurs always at the same distancein respect to the total length of the egg.The vitelline larva of the anchovy measures 2.70-3.40 mm at birth. The larva is rather undeveloped atbirth and does not show pigmentation on any partof its body. The heart at work is quite visible, but noblood circulation can be observed in the vessels. Theseappear to be typical characteristics of planktoniclarvae. The pigmentation begin to appear the thirdday after hatching. After 4 or 5 days, the vitellumhas been reabsorbed and the mouth begins to befunctional.It is impossible at present to breed larvae of theanchovy in aquaria for a period of more than 8 to 10days. After this time all the larvae die, probablybecause of the lack of appropriate food.Ossification in the larvae of the anchovy commencesrelatively late, and the first ossified elements, cleithrumand dentale, appear when the larvae have a totallength of 6 mm. When the larvae have reached alength of 33-34 mm, they have lost all of their larvalcharacteristics except the snout. At the length of44-45 mm, they resemble completely the adult individuals,and therefore pass into the juvenile stage.The influence of some environmental factors : temperature,salinity, light and mechanical factors, uponthe embryonic development of the anchovy is known.This information has been obtained by the presentauthor by means of experimental research, and hasbeen given in a paper presently in press. The temperaturehas of course a certain influence upon the speedof development. As was stated above, the developmentis quite rapid. It lasts for 68-72 hours at a temperatureof 14"-15 "C and for 50-53 hours at 19"-20" C.The optimum temperature for embryonic developmentappears to be in the range of 10"-17" C. These datarefer to the October anchovy which reproduces atlower temperatures than the Autumn anchovy, whosetemperature range might be different. A temperatureof 4" C is lethal.Experiments upon the influence of salinity haveshown that the Argentine anchovy is not so tolerantin respect to salinity threshold as some of its relatives,such as Engraulis encrasichokis. The salinity boundarieswithin which Engraulis anckoita develops inmore or less normal manner might be fixed between25.8% and 50%. Outside of this range. the developmentis abnormal, with frequent production of monstrosities.Light does not seem to have any sensible influenceupon the embryonic development of Engraulis anchoita.The embryos of the anchovy are very sensitive'-i mm2 , t mm IFIGURE 5. Termination of larval development of the anchovy (Engradis onchoifa). 1.Dz. de Ciechomski 1965).6 mm larva; 2. 13.5 mm larva; 3. Juvenile of 44 mm (from
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STATE OF CALIFORNIAMARINE RESEARCH
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STATE OF CALIFORNIADEPARTMENT OF FI
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RONALD REAGAXGovcriwr of the Slate
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PART 1REVIEW OF ACTIVITIESJuly 1,19
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REPORTS YOLUAIE SI, 1 JULY 1963 TO
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REPORTS VOLUNE XI, 1 JULY 1963 TO 3
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Page 15 and 16: REPORTS VOLUME XI, 1 JULY 1963 TO 3
Page 17 and 18: REPORTS vor,uiwIi; SI, 1 JULY 1063
Page 19 and 20: REPORTS TOT2T71\IF: SI, 1 JUJIT 196
Page 21 and 22: IiEPOHTS TOLUME XI, 1 JULY 1963 TO
Page 23 and 24: REVIEW OF THE PELAGIC WET FISHERIES
Page 25 and 26: KEI'OiiTH TOLUJIE SI, 1 JULY 1963 T
Page 29 and 30: PART IISYMPOSIUM ON ANCHOVIES, GENU
Page 31 and 32: OCEANIC ENVIRONMENTS OF THE GENUS E
Page 33 and 34: KEI'OKTS VOLIXI.: SI, 1 JULY 1963 T
Page 41 and 42: ~~~REPORTS VOLUME XI, 1 JULY 1963 T
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Page 47 and 48: 130'E 132' 134' 136' 138' 140' 142-
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Page 57 and 58: KI3I’ORTH VOLUJIE XI, 1 JULY 1963
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Page 69 and 70: INFLUENCE OF SOME ENVIRONMENTAL FAC
Page 71 and 72: REPORTS Y‘OLUJIE XI, 1 JULY 1963
Page 75 and 76: ~table shows the values calculated
Page 77 and 78: ateREPORTS T-OLTJIT", SI, 1 JULl 19
Page 79 and 80: REPORTS POLGNE SI, 1 JU LY 1963 TO
Page 81 and 82: REPORTS VOLUXE XI, 1 JULY 1963 TO 3
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Page 89 and 90: -20/5-0 10-f 5-w 25-0 20-= 15-: 10-
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Page 107 and 108: THE PREDATION OF GUANO BIRDS ON THE
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FISH E RYThe California anchovy fis
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~~ ::REPORTS VOLUME XI, 1 JULY 1963
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CO-OCCURRENCES OF SARDINE AND ANCHO
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120 CALIFORNIA COOPERATIVE OCEANIC
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CALIFORNIA COOPERATIVE OCEANlC FISH
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126CALIFORNIB COOPERATIVE OCEANIC F
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~~ ~130 CALIFORNIA COOPERATIVE OCEA
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132 CALIF0RhTTIA COOPERATIVE OCEANI
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THE ACCUMULATION OF FISH DEBRIS IN
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PART IllSCIENTIFIC CONTRIBUTIONS
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REPORTS VOLUME XI, 1 JULY 1963 TO 3
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REPORTS VOLUME SI, 1 JULY 1963 TO 3
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REPORTS VOLU&IE XI, 1 JULY 1963 TO
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SUMMARY OF THERMAL CONDITIONS AND P
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SEASONAL VARIATION OF TEMPERATURE A
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including the semiannual harmonic?
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REPORTS VOiLUME XI, 1 JULY 1983 TO
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170 CALIFORNIA COOPERATIVE OCWIC FI
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172 CALIFORNIA COOPERATIVE OCBANIC
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184CALIFORNIA COOPERATIVE OCEANIC F
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CONTENTSI. Review of Activities Pag
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