WIGLEV anJ BIRNS: DISTRIBITION AND BIOLOGY OF MVSIDS 



Table 13. — Bathymetric classification of species, based 

 on the NMFS collection. 



1. Shore Species (occur in the intertidal zone, minimum and maximum 

 depth and 1 m): 



Mysii stfnoli'pis 

 Pranuus flfxuosus 



2. Shallow Shelf Species (occur predominantly at depths less than 50 m, 

 minimum and maximum depth 2 and 84 m): 



Boumaniella portoncensis 

 Anthialina typica 

 Mysidopsis furca 

 Promysis atlantiea 

 Hi-lrTomysis formosa 



3. Eurybathic Shelf Species (occur over a broad range of depth on the 

 continental shelf, minimum and maximum depth 1 and 421 m): 



Erythropf erythrophthalma 

 Mftfrylkrops robusta 

 Myiidopsis bigelozvi 

 Mysis mixta 

 Neomysis americana 

 Psfudomma sp. 



4. Deep Shelf and Upper Slope Species (occur on the continental slope 

 and outer shelf, minimum and maximum depth 98 and 329 m); 



HyprTfTythrops caribbaea 

 Pseudomma ajfinf 

 .Imblyops ahbreviala 



5. Slope Species (occur predominantly on the continental slope, min- 

 imum and maximum depth 220 and 700 m): 



Eucopia grimaldn 

 BoTfomysis tndfns 

 Bath\m\fii renoculala 



Shallow Shelf (less than HO m) inhabitants. 

 Heternwysis formosa is included in this category 

 even though one specimen was taken at a depth 

 of 84 m. This is the only New England species 

 in this bathymetric category; all other Shallow 

 Shelf species are warm-water forms collected 

 in the southern region. Six species are listed 

 under the heading "Eurybathic Shelf Species." 

 They were each taken over a broad de])th range 

 (for example, Neomysis americana, 1-232 m) on 

 the continental shelf and occasionally on the 

 upper continental slope. Three species that live 

 along the outer margin of the continental shelf 

 are listed under the category "Deep Shelf and 

 Upper Slope Species." Depth range for these 

 species is 98 to 329 m. Three si^ecies were taken 

 at depths beyond the outer margin of the conti- 

 nental shelf, from 220 to 700 m. They are listed 

 under the category "Slope Species." 



females is the most convincing evidence; this 

 was obtained for eight species. Additionally, 

 indirect evidence from catch records of imma- 

 ture specimens provides clues to possible spawn- 

 ing seasons of seven species, including four spe- 

 cies for which direct evidence is lacking. 



Spawning of most species for which informa- 

 tion is available takes place during the warmer 

 months — May through October. Species that 

 spawn in this season are: Boivmaniella portor- 

 icensis, Erythrops erythrophthalma, Hyperery- 

 throps caribbaea, Pseudomma affine, Ambhjops 

 abbreviata, Prannus flexuosus, Neomysis amer- 

 icana, Heteromysis formosa, and possibly Buthy- 

 mysis renoculata and Mysidopsis bigeloivi. 

 One species, Neomysis americana, probably 

 .spawns in all seasons of the year with maximum 

 l^roduction in s])ring. Amblyops abbreviata and 

 Pseudomma affine spawn in winter and summer; 

 Meterythrops robusta, Mysis mixta, and M. ste- 

 nolepif: jirobably spawn in winter or early spring. 



The number of eggs or larvae per clutch was 

 counted for eight species. Although the average 

 number per clutch for different species ranges 

 from 6 to 188, these extremes are rare. For 

 most sjjecies the average brood contains between 

 11 and 30; exceptionally small clutches (6 eggs) 

 were produced only by the summer generation 

 of Neomysis americana. Unusually large 

 clutches (average of 188 eggs) were tyjjical for 

 one species, Mysis stenolepis. A moderately 

 large number of eggs (average of 44) was pro- 

 duced by Prauniis flexuosus. Both of the latter 

 species are relatively large inshoi-e inhabitants. 

 Small species commonly brood as many eggs as 

 moderately large species; within a species, how- 

 ever, the smaller specimens have fewer eggs 

 than large siiecimens. The diameter of eggs of 

 ovigerous mysids in the collection was surpris- 

 ingly uniform. Both large and small sjiecies 

 produced eggs that were approximately 0.4 mm 

 in diameter. 



SPAWNING 



Information pertaining to the siKiwning sea- 

 sons of 13 mysid sjiecies in the NMFS collection 

 is summarized in Table 11. Direct information 

 based on the cajjture of ovigerous or larvigerous 



BODY SIZE 



The smallest and largest s]iecimens (excluding 

 larvae) in the NMFS collection are 2.4 and 

 32.0 mm in body length. Body lengths were 

 measured for 18 of the 19 species represented 



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