FISHERY BULLETIN: VOL. 87, NO. 3, 1989 



during the day below the path of the net. Halh- 

 day (1970) found the center of distribution dur- 

 ing the day is below 450 m (250 fathoms) and at 

 night between 45 and 90 m (25 and 50 fathoms). 

 In contrast to B. glacials, the lanternfish, C. 

 niaderensis, was captured in all light regimes up 

 to 16 mm. With this species, night catches 

 dominated both day and twilight catches by up to 

 10 times, but the total length range captured 

 changed little, regardless of light conditions. The 

 length frequencies of Atlantic herring show a 

 distinct polymodality for both day and night 

 catches with peaks occurring at various lengths, 

 depending upon the light regime considered 

 (Fig. 4). 



The catches of rock gunnel larvae are the most 

 erratic of the 26 species presented. There 

 appears to be little decrease in abundance with 

 increasing length and they have the lowest ratios 

 of day, night, and twilight catches of any taxa. 

 Figure 4 shows a slight dominance of night 

 catches at the smaller sizes and of twilight 

 catches at the larger sizes. The minimum length 

 (10 mm) corresponds to the large hatching size of 

 rock gunnel and is the largest of any taxa treated 

 here. 



Correction Factors 



The estimates of the coefficients of the expon- 



Table 4. — Regression coefficients and mean square error (MSE) for the relationship of mean catch per 100 m^ 

 United States, 1977-84. Regression constants for the quadratic equation relating the ratios (fl) of night;day and 

 the estimate. 



Day 



Night 



Twilight 



Taxon 



MSE 



MSE 



MSE 



Atlantic herring 



Ceratoscopelus 

 maderensis 



Benthosema 

 glaclale 



Goosefish 

 Urophycis spp. 

 Fourbeard reckling 

 Atlantic cod 

 Haddock 

 Offshore hake 

 Silver hake 

 Bluefish 

 Atlantic croaker 

 Gunner 

 Rock gunnel 

 Ammodytes spp. 

 Atlantic mackerel 



4.318 

 (0.478) 



3.150 

 (0.484) 



3.691 

 (0.334) 



2.225 

 (0.308) 



4.602 

 (0.383) 



2.809 

 (0.332) 



3.185 

 (0.118) 



4.887 

 (0.339) 



3.521 

 (0.531) 



4.560 

 (0.217) 



7.453 

 (0.412) 



5.974 

 (0.622) 



5.586 

 (0.385) 



0.414 

 (0.707) 



5.710 

 (0.104) 



7.019 

 (0.181) 



-0.290 

 (0.0293) 



-0.400 

 (0.0423) 



-0.404 

 (0.0405) 



-0.383 

 (0.0323) 



-0.410 

 (0.0334) 



-0.600 

 (0.0445) 



-0.307 

 (0.0091) 



-0.442 

 (0.0336) 



-0.653 

 (0.0770) 



-0.357 

 (0.0151) 



-0.947 

 (0.0526) 



-0.913 

 (0.0834) 



-0.655 

 (0.0411) 



-0.106 

 (0.0355) 



-0.223 

 (0.0050) 



-0.782 

 (0.0243) 



0.415 



0.197 



0.046 



0.115 



0.379 



0.119 



0.034 



0.161 



0.249 



0.176 



0.116 



0.417 



0.101 



0.286 



0.045 



0.035 



4.306 

 (0.241) 



4.595 

 (0.321) 



3.790 

 (0.507) 



1.769 

 (0.514) 



4.828 

 (0.355) 



2.688 

 (0.181) 



2.423 

 (0.212) 



5.237 

 (0.458) 



3.384 

 (0.435) 



4.195 

 (0.148) 



6.260 

 (0.536) 



4.065 

 (0.505) 



5.721 

 (0.279) 



1.072 

 (0.912) 



5.926 

 (0.117) 



7.484 

 (0.432) 



-0.186 

 (0.0147) 



-0.338 

 (0.0280) 



-0.422 

 (0.0615) 



-0.348 

 (0.0539) 



-0.371 

 (0.0310) 



-0.550 

 (0.0243) 



-0.233 

 (0.0163) 



-0.546 

 (0.0453) 



-0.568 

 (0.0631) 



-0.242 

 (0.0103) 



-0.588 

 (0.0683) 



-0.445 

 (0.0677) 



-0.497 

 (0.0298) 



-0.133 

 (0.0458) 



-0.177 

 (0.0056) 



-0.701 

 (0.0579) 



0.106 



0.086 



0.106 



0.320 



0.326 



0.035 



0.109 



0.293 



0.167 



0.082 



0.196 



0.275 



0.053 



0.477 



0.056 



0.201 



5.606 

 (0.623) 



5.215 

 (1.043) 



2.281 



(0.654) 



1.268 

 (0.573) 



4.488 

 (0.394) 



1.193 

 (0.622) 



1.972 

 (0.291) 



4.354 

 (0.333) 



4.432 

 (0.484) 



4.043 

 (0.280) 



6.406 

 (0.890) 



1.891 

 (0.379) 



3.978 

 (0.923) 



-0.253 



(1.051) 



5.775 

 (0.141) 



6.583 

 (0.651) 



-0.323 

 (0.0381) 



-0.504 

 (0.0912) 



-0.204 

 (0.0794) 



-0.299 

 (0.0600) 



-0.321 

 (0.0344) 



-0.310 

 (0.0834) 



-0.223 

 (0.0225) 



-0.418 

 (0.0329) 



-0.616 

 (0.0702) 



-0.276 

 (0.0196) 



-0.770 

 (0.113) 



-0.379 

 (0.0508) 



-0.449 

 (0.0990) 



-0.0712 

 (0.0527) 



-0.203 

 (0.0067) 



-0.732 

 (0.0873) 



0.703 



0.914 



0.176 



0.396 



0.402 



0.417 



0.206 



0.155 



0.207 



0.294 



0.540 



0.155 



0.584 



0.633 



0.081 



0.457 



436 



