HERRING, GASPEREAU, SHAD AND OTHER GLUPEOIDS 



101 



SESSIONAL PAPER No. 22a 



(3) Finally, there is the typical pelagic or floating egg of some Clupeoids. All 

 pelagic eggs are marked by translucency, buoyancy and extreme delicacy of structure ;. 

 but the eggs of the sprat (Glupea spraiius,, L.) and the pilchard or sardine (Clupea pil- 

 chardus, Walb.) are of unusual delicacy and buoyancy. The ova named are practi- 

 cally spherical; but one clupeoid ovum of the pelagic type is quite ellipsoidal, viz., that 

 of the anchovy (Engmulis encrasicholus, L.). The eggs of the sprat were first dis- 

 covered by Hensen in the Baltic, and were studied in detail by Professor Pouchet in 

 Britanny, and Mr. J. T. Cunningham, who obtained them in the Pirth of Porth. They 

 are about V25 of an inch (1*016 mm.) in diameter; some, not perfectly spherical, mea- 

 suring X %5 of an inch (1-01 x -99 mm.), and the capsule is extremely tenuous, 

 while the clear colourless yolk, which almost completely fills up the capsule, shows deli- 

 cate interlacing lines or reticulations as though the yolk were incompletely divided into 

 spheres. The pilchard's egg is similar, about ^ inch (3 -8 mm.) in diameter, of extreme 

 translucency, but the yolk occupies only a portion of the chamber of the capsule. The 

 yolk substance is divided into spheres, and in its midst is seated a large oil-globule. 



The spawning season, breeding habits, number of eggs produced, and the time 

 occupied in incubation, show great variation in the Clupieiclse. We have seen that the 

 sea-herring spawns at two different seasons in the year, and that special 'areas are 

 selected year after year, where the sea-bottom presents suitable features for the deposi- 

 tion of the eggs, a hard bottom being a necessity, and usually of a rough shingly or 

 rocky nature. They spawn in 10 to 20 fathoms of water, the eggs, deposited by the 

 ripe female, being fertilized before reaching the bottom, where they adhere to zoo- 

 phytes, stones, &c. The number produced by one herring is found to range from 10,000 

 to 3Q,000 or 40,000, or even 60,000, and at 53° P. they hatch out in six to eight days, 

 while at 33° or 34° P. they take thirty to forty days. Some recent observations by Dr. 

 Jenkins embody many interesting results both as to the comparative productiveness of 

 different varieties of the sea-herring, and the proportions of male and female found in 

 certain captures of the fish carefully examined. He ascertained that eight autumn 

 herrings had in different cases from 13,000 to 65;,000 eggs, while five spring herrings 

 had from 25,264 to 45,543, the mean number for the lot being 30,000. Dr. Pulton found 

 that sixteen spring herrings had a mean of 31,7 68 eggs, the numbers in different fishes 

 varying between 21,500 to 47,466. Jenkins shows that the number varies with the size 

 and age of the fish, the smaller and younger having fewer. With regard to the propor- 

 tion of the sexes authors are not quite agreed. Pulton found that amfong 3,457 exl- 

 amined 1,724 were males and 1,733 females;, while Heincke found 822 females and 606 

 males among 1,488, and Jenkins 148 females and 155 males among 303. 



On a lake near Kiel where the water is brackish, and communication with the sea 

 has been cut off, ripe herrings were found to be considerably smaller than those got in 

 the Baltic, and to have a lower fecundit;7. Pive, for example, contained only from 

 4,245 to 7,950 eggs, the average being 5,615, and the earbones showed that the herrings 

 were three years old, while their average length was 5§ inches, and their average weight 

 16*1 grammes, or a little over -| ounce. The average length of the autumn Baltic 

 herring of similar age was 7 inches, its weight 39*5 grammes (If ounces), and the 

 number of its eggs 15,709. 



The sprat and pilchard, having pelagic or floating eggs, scatter them freely in the 

 sea, and although certain spawning areas seem to be selected by these fish each year, the 

 eggs they produce must be widely scattered in the water. The former spawns very 

 early in the year, viz., January to May,* while the pilchard is later, probably May and 

 June, or even subsequently, while in more southerly waters the period is in winter and 

 early spring. Mr. J. T. Cunningham hatched out pilchard eggs in three days and the 

 sprat take about the same short time, indeed the Clupeoids appear generally to develop 

 rapidly, and whereas the salmon, trout and similar fishes, with large, heavy eggs, take 

 from 90 to 160 days, normally rather less than the latter period, and even cod, had- 



* Professor Mclntosli obtained specimens abundantly early in May at St. Andrews, Scot- 

 land. 



22a— 9 



