Comyns and Grant: Urophyas and Phycis larvae and pelagic juveniles 



217 



NJ 

 38°42-39°2l' 



AUGUST 197 7 



37°05'-37°3l' 



AUGUST-SEPTEMBER 1976 



+ 



I' 



O 



O I- 





□ n = 27504 

 Hn=2770 



NOVEMBER 1976 



CI 01 N3 E3 F2 J 



Station 



LI L2 L4 L6 



Figure 5 



Mean abundance of Urophycis chuss in neuston and bongo 

 collections at stations off Virginia and New Jersey, October 

 1975-August 1977. n = number of larvae collected. Neuston 

 catches are denoted by clear histograms; bongo catches by 

 stippled histograms. NS = no samples taken. Star denotes 

 bongo catches exceed neuston catches. 



ginia coast at midshelf station L2 (Fig. 7). Densities of 

 U. regia were much lower in collections taken in Feb- 

 ruary and March, and most specimens were pelagic 

 juveniles found at offshore stations off both Virginia 

 and New Jersey. By May, U. regia was scarce; only 

 seven neustonic juveniles were found at offshore sta- 

 tions. 



Urophycis tenuis Apart from an occasional U. regia 

 juvenile found at offshore stations, U. tenuis was the 

 only species of hake present in spring plankton collec- 

 tions off Virginia and New Jersey. Abundance of U. 

 tenuis in May 1977 was up to one order of magnitude 

 greater than abundances in June 1976 (Fig. 8). Larvae 

 were collected at all but inshore stations off both Vir- 

 ginia and New Jersey, but were most abundant at off- 

 shore stations. Larvae were smallest at offshore sta- 

 tions and increased in size as collections proceeded 

 inshore (Fig. 9, page 220). 



Urophycis floridana and U. cirrata Urophycis floridana 

 (ra=41, 13-32 mmSL) and U. cirrata (n=5, 20-42 mmSL) 

 were found exclusively in offshore winter collections 

 (Fig. 10, page 221). With the exception of a single juve- 

 nile U. floridana (23.0 mmSL) captured in a bongo tow, 

 all specimens were found in neuston samples. 



Phycis chesteri Phycis chesteri larvae first appeared 

 in fall neuston collections from the Middle Atlantic 

 Bight; 16 larvae 6-13 mm in length were collected in 

 November 1976 at offshore stations off Virginia 

 (Fig. 11, page 221). Phycis chesteri larvae and pelagic 

 juveniles remained in surface waters during winter 

 and were found in water deeper than -100 m off both 

 Virginia and New Jersey (n=41). All specimens were 

 collected with the neuston net. 



Discussion 



Because of similarities between larvae of the seven 

 hake species found in the MAB, a dichotomous key is 

 not a practical tool with which to identify hake larvae 

 in this area. However, the specific identification of lar- 

 val and pelagic juvenile hake is feasible using a suite 

 of diagnostic characters (App. Table 2). Identifications 

 in this study were based on comparison of larval 

 meristics with adult meristics. Further examination of 

 larvae revealed diagnostic characters comprised not 

 only of meristic information, but also morphometric 

 and pterygiophore interdigitation data. Spawning sea- 

 son and capture location were not used as 'characters' 

 to identify larvae in this study. 



Methven (1985) had limited success using pigment 

 characters to separate U. chuss and U. tenuis >7-8 mm. 

 Problems will persist with the identification of small 

 hake larvae until ontogenetic pigment patterns of all 

 species have been described. These ontogenetic pig- 

 ment patterns, when used in concert with meristic char- 

 acters, will hopefully enable relatively routine identifi- 

 cations of these taxa. 



The only species of Urophycis not found in the 

 present study was U. earlli. Adult U. earlli are rare 

 and larvae remain undescribed, but they are expected 

 to co-occur with U. floridana (Hildebrand & Cable 

 1938). Both species are similar in having two epi- 

 branchial gill rakers, but numbers of first dorsal-fin 

 rays, abdominal vertebrae, and caudal-fin rays delimit 

 most specimens of these two species. 



Larval and juvenile Urophycis or Phycis were present 

 in the MAB throughout the year, and patterns of spa- 

 tial and temporal distribution of larvae were consis- 

 tent during both years of this study. Urophycis ch uss 

 larvae were found in summer and fall collections, with 

 greatest abundances occurring during summer in the 



