THE WESTERN MACKEREL FISHERY. 285 



Second Position. — 21 miles S. x W. | W. of Start. 



Depth, 39 fathoms. 



Condition of bottom, coarse sand, fine gravel. 

 Temperatures : surface, 9"4:5°. 

 16 fathoms, 8"65°. 

 Bottom, 39 fathoms, 8"65°. 



General condition of plankton* taken by coarse and fine nets : — 



Bottom (o9 fathoms). Four species of Copepods, chiefly Temorci longi- 

 cornis, not abundant ; few other metazoa, including Oikoplcura dioica, 

 rare. 



Phytoplankton in excess of zooplankton, composed largely of 

 diatoms, Lauderict borealis and Chaetoceras dcnsum, both common. 



Fourteen other species of diatoms observed. 



Surface plankton, similar in every respect to the bottom samples but 

 slighter in bulk. 



Petersen trawl samples from surface, midwater and bottom were 

 composed largely of several species of amphipods : Aphereusa bispinosa, 

 very abundant, Bathyporeia pelagica, rare, Euthemisto gracillipcs, rare, 

 Monoculodes sp., rare, Paratylus vedlomensis, rare, Stenotho'e marina, 

 rare, Urothoe elegans, rare, etc. Schizopods, viz. Anchiahcs agilis, 

 rare, Gastrosaccus spinifer, rare, Mysidopsis angtista, rare, and M. 

 giibosa, very rare. A fair number of post-larval fish were also 

 taken, including Clupea harengus, plentiful, Pleuronectes rnicrocephalus, 

 common, Solea variegata, rare, etc. 



An unsuccessful attempt was made to obtain mackerel in the otter 

 trawl. The following species, however, were taken after a two hours' 

 haul : Arnoglossus laterna and A. inegastoma, Callionymus lyra, Gadus 

 minutus, G. luscus, and G. merlangus, Gobius quadrimacidatus, Pleuronectes 

 platessa, Baict bland a, Bhombus laevis, Solea variegata, and S. lascaris, 

 Trachinus draco, Trigla cuculus, T. gurnardus, T. liirnndo, and T. lineatciy 

 Zeusfcdier, together with several invertebrates. 



III. GENERAL CONDITIONS OBSERVED IN STOMACHS OF MACKEREL TRAWLED 

 ON THE START GROUND. 



The contents of six stomachs were examined from the fish taken by 

 the Condor on March 24th, 1907. A general determination based upon 

 the six samples will be found in the Food and Plankton Tables 

 (Table Y), Sample No. 2-1-. It is desirable, however, to describe the 

 present material more particularly. In the six samples there appeared 

 to be two distinct types of food, together with intermediate stages, in 



* See Plankton Tables, Sample No. 38. 



NEW SERIES. — VOL. VIII. NO. 3. U 



