FIl'TEKN-Sl'lNEl) STICKLKHACK. 



643 



'it w;is !i female", groenisli in I'olinir, tliat was husv 

 near tlu^ laiuliiig-staae, in alxnit 7 oy S dm. of water, 

 huildiii.i:' a dwelliiii!', or a kind of nest, for the eggs 

 soon to lie d(']M)sit('d. Ill a round iioliow, nhoiit 2' ._, 

 cm. deep and 1") cm. in diameter, in the S!ind\' bottom, 

 she placed, several times an hour, small fragments of 

 dead jilants, which she found during her wanderings 

 in the neighbourliood and carried in her mouth to the 

 s|)ot. Now and then she worked herself into the heap 

 thus collected, turning ipiickh' round and round, and 

 emerged on the other side of the jiile. in this manner 

 she carded the Iniilding-materials with the stiff and 

 shar]) rays of lier tins, and at the same time oiled them 

 with the slime secreted 1)\' her own body, thus forming 

 an elastic tube, in which she finally deposited her eggs. 

 The male in his more bluish dress kept guard, swim- 

 ming round and round the spot, and now and then 

 rewarded by a I'riendly greeting from the female, while 

 the enemies of the roe, the shrimps and shore-crabs 

 etc., were repulsed by the powerful onslaughts of the 

 brave sentinel, as soon as they ventured to approach 

 his post, 'file female was oftt'ii compelled to come to 

 the rescue, but the fish were alwaj's victorious. l)ut 

 if another male of the same species came up, he was 

 at once joined by his host in some fi'iendly sport, which 

 ended in a regular game of ti{/ among the stones and 

 seaweed several yards from the spot. But as soon as 

 the host saw that he had led astray his uninvited guest, 

 whom he had evidently enticed from the spot by this 

 stratagem, he returned at full speed, to resume at the 

 next moment the defence of his home and family. They 

 paid no attention to fishes of other sjiecies, such as 

 Gobies etc." From this observation Malm concludes 

 that the Fifteen-spined Stickleback lives in pairs, at 

 least during the sjiawning-season, and is not polyga- 



mous like the other Sticklebacks; while it would also 

 seem to lie jiciuliar to this species that the female 

 should liuild (he nest and take part in its defence. 

 Other observers, however, an; of fjjiinion that here too 

 the male is the actual builder, but that the nest is 

 guarded both b\' the male and the female. The parents 

 continue their vigilant care of the eggs and the new- 

 hatched young for at least thi-ee or four weeks. Ene- 

 mies are repulsed; if the nest is damaged, they repair 

 it; if they are driven away, they soon I'cturn. If the 

 nest be built between the tide-marks, they must, of 

 course, leave it to its fate during the ebb; but the 

 moisture retained by the walls of the nest suffices to 

 keep the eggs or young alive until the; tide rises again. 



Of the growth of the fry we learn from the col- 

 lections of the Royal Museum that during the expedi- 

 tion of the gunboat GunhUd, on the 25th of July, 1878, 

 a young specimen iV'^ mm. long was taken at a depth 

 of four fathoms on a stony and weedy bottom, in the 

 south of the Sound between Malmo and Falsterbo. It 

 belonged, no doubt, to the fry of the same year. On 

 the Irish coast Thompson* found young specimens 19 

 mm. long in June and others, 25 mm. long, in July. 

 Through Professor Lindstrum the Royal Museum has 

 acquired some young specimens between 57 and 71 

 mm. in length and taken on the coast of Gothland in 

 August, 1852. These last specimens, however, can 

 hardly have been less than a year old. 



The S(jlitary life of the Fifteen-spined Stickleback, 

 which prevents it from ever being caught in any quan- 

 tity, deprives it of all special importance to man in an 

 economical respect. It is taken only by accident among 

 other fishes in small-meshed nets or the seine; and it is 

 utilised only in the manufacture of oil and as manure. 



(Ekstroj[, Smitt.) 



" As the nest was afterwards destroyed by accident and tlie fish were frigliteiied away, Malm was prevented from ascertaining by 

 closer examination wliether this specimen was really a female, and her companion a male. 

 "• Nat. Hist. Trel., vol. IV, p. 90. 



