FISHERY BULLETIN: VOL. 84, NO. 4 



Other causes of injury and death in the later part 

 of RW culture were 1) swimming into the water in- 

 take pipes, 2) jetting out of the water and hitting 

 the bottom of the polystyrene tank covers, and 

 3) colliding occasionally with the walls and slowly 

 accruing fin damage. The resulting abrasions on the 

 body and fins (Fig. 14) were probably the main fac- 

 tor influencing mortality after about 60 d of cul- 

 ture. 



1 or 2 d. They usually had some obvious skin damage 

 and were probably unable to maintain disciplined 

 swimming with the school. 



Sexual Maturation, Mating, 

 and Egg Laying 



In L.0. 1981, the first signs of sexual maturation 

 were when chromatophore patterns associated with 



Figure 14.— Fin and skin damage that resulted in mortality of cultured squid. A, Epidermis and dermis missing on periphery of fins, 

 with fin margin thickened from scar tissue. B, More extreme case with damage extended to mantle. C, Excessive skin damage on 

 ventral mantle caused by scrapping the tank bottom. A hole (arrow) was produced in the mantle wall and prevented jet-propulsed swimming. 



Schooling Behavior 



The squid were able to hold a swimming position 

 in the tank between days 41 and 44 in both L.0. 1981 

 and 1982, corresponding to a mantle length of about 

 10 mm. In the early phase of RW culture in L.O. 

 1981 and 1982, squid swam in two or three loose 

 groups throughout the RW. Later, they schooled 

 together at both ends. The reasons for this behavior 

 are unknown, but it may have been related to lower 

 illumination levels at the RW ends or to the well- 

 aerated seawater entering the RW at these points. 

 Individuals not schooling were often found dead in 



courting were observed in males. On day 174 two 

 males showed the "Shaded testis" component of pat- 

 terning similar to that described in Loligo plei 

 (Hanlon 1982). Later, other chromatic components 

 of patterns seen in mature males of Loligo plei were 

 observed: faint, lateral stripes on the mantle 

 ("Lateral flame"); a discontinuous suture line along 

 the fin margin ("Stitch work fins"); a clear area in 

 the dorsal portion of the mantle above the testis 

 ("Accentuated testis"). 



Maturation and spawning occurred earlier in L.O. 

 1982 than L.O. 1981 (Fig. 13). The penis was first 

 recognizable in a 100-d-old male (25 mm ML) and 



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