18 



Hardening of the shell appears to take place fairly quickly. 

 On 30th April, 1912, a trip was taken on one of the vessels 

 fishing for prawns. It was noticed that only one or two males 

 were taken in a really soft condition, but many were caught 

 with the sliell quite clean, and although not so hard as in 

 individuals which had not cast, considerable pressure had to 

 be applied with the finger and thumb before it was possible to 

 break the shell of the chelte. 



With the exception of January and March, females which 

 have recently cast have been found in every month of the year, 

 but by far the greater numbers occur from June to September, 

 the highest percentage obtaining in July. 



If the particulars relating to casting, spawning, hatching, 

 and maturity of males be now considered together, it will be 

 seen that that the males cast chiefly in j\Iarcli and April, later 

 the young hatch, and the highest percentage of casting females 

 shortly afterwards occurs in the months June to September. 

 In August, the greatest number of males with external signs 

 of maturity was obtained. 



It is not suggested that these observations are complete, and 

 by work at the Laboratory I hope to be able to give further 

 particulars relating to spawning, hatching and the period of 

 incubation, and also to obtain some facts relating to the life 

 history of Nephrops. 



Tides and Catches. — It is generally held amongst the fisher- 

 men that the greatest catches of Norway Lobsters are made 

 when the tides are " easy " or neap, and the smallest catches 

 during the " heavy " or spring tides. In order to ascertain if 

 this was correct for a period extending over a year, the follow- 

 ing particulars have been considered by means of statistics 

 kindly supplied by the Board of Agriculture and Fisheries for 

 the year 1911. The year has been divided into lunar months, 

 commencing with the new moon ; the mean landings of Norway 

 Lobsters in cwts. for vessels absent from the port for one day 

 have been calculated for each day of the lunar month, and a 

 curve has been drawn. The state of the tide is shown by 

 taking the depth of water in feet at the mouth of the Tyne 

 during September, 1911. It is obvious that the great3st depth 

 of water will be during the spring tides. 



