FISHERY BULLETIN: VOL. 80, NO. 3 



Figure 1.— Inshore and offshore sampling locations on the 

 coast and continental shelf of New England. The study area in 

 lower Narragansett Bay is indicated by shading in the inset. 

 Depths in meters. 



tissue. Frequently, the length of typical sperma- 

 tophores can be determined while still within 

 Needham's sac or the penis. Mantle width (MW, 

 Table 1), a measure of mantle circumference, 

 was defined as the distance across the widest 

 part of the mantle when opened flat to form a 

 rough isosceles triangle. Mantle thickness (MT) 

 was measured at the thickest portion along the 

 midventral incision. All weight measurements 

 were blotted fresh or live weights (e.g., wet 

 weight, WW, and gonad weight, GW) and were 

 recorded to the nearest 0.01 g if <120 g or to the 

 nearest 0.1 g if >120 g, on a top-loading digital 

 balance. The relative abundance of spermato- 

 phores in Needham's sac (ASN), in the penis 

 (ASP), of eggs in the ovary (AEO), or in the ovi- 

 duct (AEOV) were scored on the basis of "none," 

 "a few," or "many" present. In females, a distinc- 

 tion was also made between immature and ma- 

 ture eggs (Table 1). The four variables — ASN, 

 ASP, AEO, and AEOV — were purposely scored 

 on this nonquantitative basis to avoid time-con- 

 suming enumeration. After completing the 

 above length measurements and abundance esti- 

 mates, the complete reproductive tracts, includ- 

 ing gonadal products (Table 1), were dissected 

 out and weighed (GW). From the tabulated raw 

 data the various proportional indices (GI, MWI, 

 MTI, TLI, SPI, NGI, and AGI (see Table 1)) were 

 then computed. 



min trawl tows. The selected squid were bagged 

 and placed in chilled containers for transporta- 

 tion to the laboratory, where they were either 

 immediately examined or were quick-frozen at 

 — 25°C for storage. Additional frozen samples of 

 100-500 squid each were obtained from the Na- 

 tional Marine Fisheries Service, Woods Hole, 

 Mass.; from offshore surveys by the French vessel 

 Cryos conducted during November-December 

 1975 and 1976; and from the Russian vessel Argus 

 during November 1977 and March 1978 (Fig. 1). 

 Only the 1976 Narragansett Bay and Cryos sam- 

 ples were used to develop and verify the classifica- 

 tion system described here. The new system was 

 then used to classify the 1977 and 1978 samples. 

 For analysis, squid were opened midventrally 

 to expose internal organs and allow sexing. 

 Twenty characters were then determined (Table 

 1). Length measurements were made to the near- 

 est millimeter using a ruler along the greatest 

 dimension, taking care not to stretch the organ or 



Table 1.— The initial 20 input parameters tested for classi- 

 fying squid into maturity stages. See Figure 3 for organ iden- 

 tification. 



Mantle length, cm = DML = dorsal mantle length 



Wet weight, g = WW = total live weight 



Mantle width, cm = MW 



Mantle thickness, cm = MT 



Gonad weight, g = GW' 



Gonad index = GW/WW = GI 



Mantle width index = MW/DML = MWI 



Mantle thickness index = MT/DML = MTI 



Males: 



Testis length, cm = TL 



Spermatophore length, cm = SPL 2 



Abundance of spermatophores in Needham's sac = ASN 3 



Abundance of spermatophores in penis = ASP 3 



Testis length index = TL/DML = TLI 



Spermatophore length index = SPL/DML = SPI 

 Females: 



Nidamental gland length, cm = NGL 



Accessory gland length, cm = AGL 



Abundance of eggs in ovary = AEO 4 



Abundance of eggs in oviduct = AEOV 3 



Nidamental gland index = NGL/DML = NGI 



Accessory gland index = AGI/DML = AGI 



'For females: (nidamental + accessory + oviducal glands) + ovary/ 



oviduct + eggs. 

 For males: testis + (Needham's sac +spermatophoric organ + penis). 

 2 Length of an average spermatophore excluding tail (= cap thread), 

 scored as "0" if not present or if visible only as a round speck 

 3 Scored on a 1-3 scale, where 1 = none, 2 = "a few," 3 = abundant. 

 'Scored on a 1 -5 scale, where 1 = none, 2 = "a few" immature, 3 = many 

 immature, 4 = "a few" mature, 5 = many mature. 



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