84 



MARINE AND FISHERIES 



6-7 EDWARD VII., A. 1907 



the smaller specimens, 20-26 mm., are found both in the tidal pools and in the brackish 

 water ponds, and in both sizes the genital organs were found to be mature. I made 

 accurate measurements of seven examples, and found that, in three of them, the first 

 dorsal spine does not reach the second, in one the tip just touches the base of the second, 

 and in three it projected beyond the base of the second. The ratio of length to height in 

 the seven are 4 -3;, 4 -.1, 3 -8, 4 -2, 4 -3 and 4 -9, hence the distinction which has been 

 drawn between G. spinosus and G. aculeatus does not hold in the case of the Canso 

 specimens. I made some endeavour to decide if other peculiarities could be correlated 

 with the red throat and red fin membrane which many exhibited. Out of 245 specimens 

 collected from the pond, 16 were distinctly red-throated, and 8 red-throated specimens 

 examined were found to be males with active spermatozoa in the testes. Out of 10 with 

 pale throat 5 were females and 5 proved to be males showing active spermatozoa. 



10. Apeltes quadracus (Mitcnell) . — This species was common in a brackish pond near 

 the beach. The head I found to be contained 4 -3 times in length, and the depth 4 -3- 

 4 '8 in the length. The anal spine does not come under the third dorsal ray, but undetf 

 the fourth, fifth or even under the seventh. In a large number the ventral fins have 

 orange-red membranes, and sometimes the membrane of the dorsal and the anal 

 spines are red. All with coloured membranes I ascertained to be males, and sevdn 



, specimens not so tinted were females. I could detect no external marks of difference 

 in the colouration of males and females excepting the red membranes. The dorsal 

 spines are bent irregularly to the right and left, and in about one- third of the exam- 

 ples obtained the dorsal spines were four in number. 



family: scombrid^. 



11. Scomber scombrus (Linnaeus). — Of this valuable food-fish variable quantities are 

 captured by gill-nets and traps. They -are usually shipped fresh to the Canadian mar- 

 kets, the fishermen receiving two to ten cents a piece for them, and the fishing season 

 lasts from May to November. In one season recently over 250,000 mackerel were taken 

 by Canso fishermen. 



12. Thynnus thynnus (Linnaeus). — The mackerel traps often capture specimens of 

 this large species about the end of July and in the month of August. They are often 

 called by the erroneous names, mackerel shark or horse-mackerel, the former being 

 really the porbeagle (Lamna) and the latter the scad (Trachurus) . The name tunny 

 is correct and most appropriate, and in the Mediterranean sea it is one of the principal 

 fisheries pursued, while in Japan it is an esteemed food-fish, raw, salted;, smoked and 

 canned in oil. At Canso they are occasionally captured, but one trap in a. few weeks 

 took over forty. All were liberated, as there is no market for them. They are often 



■seen swimming near the surface of the sea. 



family: ammodytid^. 



13. Ammodytes americanus (DeKay). — This species was found only at one point at 

 Canso. On a sandy beach at the entrance of a cove connected with Canso harbour they 

 occurred very numerously at low tide. The drag seine used at this place on being 

 hauled in quickly captured many hundreds in a short time. They were often found 

 stranded on the shore as the tide went out, and were also dug out of the sand at a depth 

 of six inches. They appeared fo be of two sizes, without intervening stages. Twenty- 

 five of the larger ranged from 157 mm. to 184 mm. in length, and ninety of the smaller 

 xype were found to measure 60 mm. to 89 mm. in length. The stomach was oftei\ 

 empty ; but when filled contained small Crustacea, some of which were not secured in 

 ,tne immediate locality, and did not appear to occur locally. 



