FIFTEEN-SPINED STICKLEBACK. 
643 
“It was a female", greenish in colour, that was busy 
near the landing-stage, in about 7 or 8 dm. of water, 
building a dwelling, or a kind of nest, for the eggs 
soon to be deposited. In a round IioIIoav, about 2 7 2 
cm. deep and 15 cm. in diameter, in the sandy bottom, 
she placed, several times an hour, small fragments of 
dead plants, which she found during her wanderings 
in the neighbourhood and carried in her mouth to the 
spot. Now and then she worked herself into the heap 
thus collected, turning quickly round and round, and 
emerged on the other side of the pile. In this manner 
she carded the building-materials with the stiff and 
sharp rays of her fins, and at the same time oiled them 
with the slime secreted by 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 iioav and then 
rewarded by a friendly greeting from the female, Avhile 
the enemies of the roe, the shrimps and shore-crabs 
etc., Avere repulsed by the powerful onslaughts of the 
brave sentinel, as soon as they ventured to approach 
his post. The female was often compelled to come to 
the rescue,' but the fish Avere always victorious. But 
if another male of the same species came up, he Avas 
at once joined by his host in some friendly sport, Avhich 
ended in a regular game of tig among the stones and 
seaweed several yards from the spot. But as soon as 
the host saAv that he had led astray his uninvited guest, 
Avhom 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 species, such as 
Gobies etc.” From this observation Malm concludes 
that the Fifteen-spined Stickleback lives in pairs, at 
least during the spaAvning-season, and is not polyga- 
mous like the other Sticklebacks; while it would also 
seem to be peculiar to this species that the female 
should build the nest and take part in its defence. 
Other observers, hoAvever, are of opinion that here too 
the male is the actual builder, but that the nest is 
guarded both by the male and the female. The parents 
continue their vigilant care of the eggs and the new- 
hatched young for at least three or four Aveeks. Ene- 
mies are repulsed; if the nest is damaged, they repair 
it; if they are driven aAvay, they soon return. 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 Avails of the nest suffices to 
keep the eggs or young alive until the tide rises again. 
Of the growth of the fry Ave learn from the col- 
lections of the Royal Museum that during the expedi- 
tion of the gunboat Gunhild, on the 25th of July, 1878, 
a young specimen 3l7 2 mm. long Avas taken at a depth 
of four fathoms on a stony and Aveedy 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 6 found young specimens 19 
mm. long in June and others, 25 mm. long, in July. 
Through Professor Lindstrom 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, hoAvever, can 
hardly have been less than a year old. 
The solitary 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. 
(Ekstrom, Smitt.) 
“ As the nest was afterwards destroyed by accident and the fish were frightened away, Malm was prevented from ascertaining by 
closer examination whether this specimen was really a female, and her companion a male. 
b Nat. Hist. Irel ., vol. IV, p. 90. 
