i 9 4i CATALOGUE OF FISHES OF TORTUGAS gg 



Mycteroperca vencnosa (Linnaeus). Yellow-fin grouper 



(Plate 6, figures i, 2; plate 7, figures 1, 2) 



Perca venenosa Linnaeus, Syst. nat., 10th ed., 1758, p. 292 — Bahamas (after Catesby). 

 Bodianus apua Bloch, Naturgesch. ausland. Fische, vol. 4, 1790, p. 50, pi. 229 — Brazil. 

 Johnius guttatus Bloch and Schneider, Syst. ichth., 1801, p. 77. 

 Serranus cardinalis Cuvier and Valenciennes, Hist. nat. poiss., vol. 2, 1828, p. 378 (after 



Parra). 

 Serranus rupestris Cuvier and Valenciennes, Hist. nat. poiss., vol. 9, 1833, p. 437 — Santo 



Domingo. 

 Serranus petrosus Poey, Memorias, vol. 2, i860, p. 136 — Havana. 

 Mycteroperca venenosa apua Jordan and Eigenmann, Bull. U. S. Fish. Comm., vol. 8, 1888 



(1890), p. 370. 

 Mycteroperca bowersi Evermann and Marsh, Bull. U. S. Fish Comm., vol. 20, pt. 1, 1900 



(1902), p. 158, fig. 45 — Culebra Island, Puerto Rico. 

 Epinephelus (Mycteroperca) bonaci Metzelaar (not of Poey), Trop. atl. Vissch., 1919, 



p. 50, figs. 17, 18 — Curasao. 



This common species appears to attain a larger size at Tortugas than any other 

 grouper except the jewfish. In appearance it varies greatly with age and with the 

 circumstances in which it is found. In the young the contrast between light and 

 dark areas is sharper than in adults. At least, the dorsal dark areas are encroached 

 upon by the intervening light ones till the fish has only a few dark spots dorsally 

 on creamy ground, much more commonly in the young than in the adult. But at 

 all ages the fish is highly changeable. 



A large specimen on rough bottom appeared in a moderately dark phase, but 

 as it swam five times its own length across bare sand it became pale, and as it 

 came to rest under coral heads it turned almost black. Again, as it swam with 

 leisurely motion three or four times its length over pale sand, its pallor returned. 

 In the pale phase the rounded dark areas, with light reticulum between, are 

 largely suppressed toward the ventral side. Color changes, however, are not 

 always adaptive. A fish at the Laboratory wharf rushed so far into the shallows 

 in pursuit of a snapper as to become stranded for a moment, when its color be- 

 came very dark over white sand. 



These fish are among those commonly inspected, supposedly for parasites, by 

 Elacatinus oceanops, of which I have seen half a dozen examining them at once, 

 while a pair of small Anisotremus virginicus conducted an independent survey. 



By checking the material in Amsterdam I found that 2 specimens, 175 and 310 

 mm. in length, from St. Eustatius and Curasao, regarded as Myctoperca bonaci 

 by Metzelaar (see citation above), belong to this species. 



Without having actually had in hand specimens of M. venenosa apua Jordan 

 and Eigenmann (possibly not of Bloch; see citations above), I venture to place 

 it in synonymy. It is said to differ from the normal form only in color. Numbers 

 of fish from deep water in a red phase became like those from shallow water 

 when they were confined with them. 



The type of M. bowersi is a normal specimen of M. venenosa, preserved in a 

 dark phase such as often passes in a moment. 



Atlantic coast of tropical America to Florida and the Bahamas. W. H. L. 



