Calanus—a Further Record

ON getting back to Tobermory on Saturday, we found the plankton to be in marked contrast to its condition four weeks ago (see NATURE, p. 504). The vast swarm of Calanids has gone, and there are now no signs of mackerel feeding in the bay. In fact, the change has been noticeable for some days in the seas outside, and we have not been getting lately the large plankton catches that were usual in the latter half of July. On July 14 a haul of the large surface tow-net, in the open sea off Ardnamurchan, gave such a huge catch of Calanus (about 1000 c.c.) that we promptly took a second similar haul, and had it cooked as a sort of potted ``shrimp'' confection for tea (sampled by ten persons, including the crew, who were much interested to try this new edible ``fish'') while on August 11 a haul of the same net, taken at the same spot, gave only a small catch of some 15 c.c., containing very few Calanids, along with the usual scanty summer zoo-plankton. I have not yet seen any statistics of the mackerel fishery, but should not be surprised if this proves to be an exceptionally good year in this neighbourhood, especially in July.