the interpretation of the hyaline zones. 



Using the length at age data, a Walford growth 

 transformation graph was plotted (Beverton and 

 Holt 1957). Instead of calculating the L^, we used 

 our largest specimen (66 mm HL ). The estimate of 

 Brady's coefficient (K) obtained from this graph was 

 0.276. Using the Walford graph, the head lengths 

 for those presumed ages >4 yr could be iteratively 

 generated. This method gave a maximum age of ap- 

 proximately 11 yr. The von Bertalanffy growth equa- 

 tion for length was 



L t = 66 (L - e 



-0.276 (T+0. 



16) ). 



Rannou (1976) studied the age and growth of a 

 congener (N. sclerorhyncus) that occupies a similar 

 depth range in the western Mediterranean. He 

 calculated a K coefficient of 0.16 and an L^ of 42.31 

 mm HL. Thus, although this species is smaller than 

 N. bairdii, it has a much slower growth rate, prob- 

 ably attributable to lower productivity in the western 

 Mediterranean compared with the slope off the mid- 

 Atlantic coast of the United States (Koblentz-Mishke 

 et al. 1970). 



The length-weight regression for N. bairdii (Fig. 

 2) was analyzed. The solution of the line for N. bair- 

 dii males was log (weight) = 0.038 (head length) 

 + 0.083, r 2 = 0.810, and for females it was log 

 (weight) = 0.035 (head length) + 0.216, r 2 = 0.760. 



These length-weight relationships are not unlike 

 those summarized by Gordon (1979) for other small 

 macrourids (Coelorinchus coelorinchus, C. occa, and 

 Nezumia aequalis). 



In summary, larger N. bairdii were captured 

 deeper and the minimum and maximum depths of 

 capture off the mid-Atlantic coast were 270 m and 

 1,644 m. The fish seasonally migrated to deeper 

 water with the mature fish occurring deeper than 

 immature fish. The males matured at about 45 mm 

 HL and the females became mature at 44 mm HL. 

 Nezumia bairdii probably spawned pelagic eggs in 

 July and August and the young apparently remained 

 pelagic until the second winter (January), when they 

 first appeared in bottom trawls. The maximum age 

 of N. bairdii was presumed to be 11 yr. The 

 temperature range for N. bairdii was from 3.7° to 

 10.0°C, with the average temperature of capture 

 being 5.3°C (Fig. 6). 



Coryphaenoides rupestris (Gunnerus 1765) 



Coryphaenoides rupestris is a large macrourid that 

 reaches a total length of about 100 cm (Sawatim- 

 skii 1971; Nodzinski and Zukowski 1971; Marshall 



FISHERY BULLETIN: VOL. 84, NO. 1 



and Iwamoto 1973), and is found on both sides of 

 the North Atlantic. In the eastern North Atlantic 

 it ranges from the Trondhjem area to the Bay of 

 Biscay. In the western North Atlantic it is reported 

 to occur from Davis Strait to ca. lat. 37°N (Marshall 

 and Iwamoto 1973), although two specimens (81 and 

 100 mm HL) were captured by C. Richard Robins 5 

 at lat. 23°29.8-32.0'N, long. 77°05.5'W. The depth 

 distribution of C. rupestris varies from about 180 

 to 2,200 m (Leim and Scott 1966) with highest abun- 

 dance occurring between 400 and 1,200 m (Marshall 

 and Iwamoto 1973). 



Coryphaenoides rupestris is rarely used as a food 

 fish in the United States, but the German 

 Democratic Republic, the Soviet Union, and Poland 

 fish commercially for it in the western North Atlan- 

 tic In 1968, the Soviets recorded a harvest of 30,000 

 tons of C. rupestris off Labrador, Baffin Island, and 

 Greenland (Nodzinksi and Zukowski 1971). The 

 catches of this macrourid were reported to increase 

 during the second half of the year as the catches of 

 redfish and cod decreased (Sawatimskii 1971). 



Coryphaenoides rupestris was captured in the Nor- 

 folk Canyon area at depths of 578-1,698 m (Fig. 3). 

 Sawatimskii (1971) reported that C. rupestris is 

 known to form dense aggregations off the coast of 

 Labrador. In November 1974 an anomalous catch of 

 over 6,000 C. rupestris with a total weight >1,000 

 kg was obtained in a half hour tow in the Norfolk 

 Canyon area. A random subsample of 1,000 speci- 

 mens was examined and no sexually mature fish 

 were found. Although the head length ranged from 

 59 to 110 mm, the length-frequency curve was 

 strongly unimodal at 76 mm. The greatest number 

 and biomass of C. rupestris caught in "normal" half 

 hour tows was 128 fish comprising 39% of the in- 

 dividuals and 68 kg, and representing 65% of the 

 total catch by weight. The largest specimen captured 

 had a head length of 155 mm. 



The head length distribution by depth and by 

 cruise (Fig. 13) suggested a mass movement of C. 

 rupestris toward deeper water during the summer 

 months, and a reciprocating movement to shallower 

 water in the winter. In January, the majority of C. 

 rupestris was captured between 700 and 800 m, 

 while in June and September there appeared to be 

 a movement toward deeper water. By November the 

 depths of capture decreased and were similar to 

 those of January, and the slope of the head length- 

 depth regression for C. rupestris was significantly 



5 C. Richard Robins, Rosenstiel School of Marine and Atmospheric 

 Science, Division of Biology and Living Resources, 4600 Ricken- 

 backer Causeway, Miami, FL 33149. 



48 



