LEWIS and YERGER: BIOLOGY OF FIVE SEAROBINS 



P. roseus, this species showed a significant 

 (P<0.001) positive relationship between increas- 

 ing size and increasing depth. 



No statistical differences in catch per unit effort 

 between bottom types (Table 2) or night and day 

 collections (Table 3) were observed. 



Determination of size at sexual maturity in P. 

 martis was inexact due to a paucity of specimens 

 less than 100 mm SL. Individuals of both sexes at 

 100 mm SL were mature, while nine specimens 

 below this size were immature. Consequently 100 

 mm SL was tentatively given as the size at sexual 

 maturity for both sexes. Likewise, the exact 

 spawning season for this species was difficult to 

 determine. Females with numerous ripe ova (0.6 

 mm in diameter) were collected from October to 

 December 1970. A large sample of females in 

 January 1971 contained no ripe individuals, 

 while a sample from April 197 1 contained one ripe 

 female. 



Prionotus martis fed primarily on crustaceans 

 but not as extensively as the previous three 

 species (around 80% of the total stomach con- 

 tents). Juveniles (Table 4) appeared to feed heav- 

 ily on amphipods, polychaetes, and decapod crabs; 

 adults (Table 5) on decapod crabs and shrimp, 

 amphipods, and cephalochordates. The only 

 other important food items for adults were poly- 

 chaetes and very small fishes (usually less than 

 15 mm SL). 



Prionotus stearnsi Jordan and Swain 

 Shortwing Searobin 



Prionotus stearnsi was collected widely at 

 depths of approximately 60 to 185 m (Figure 4b) 

 and temperatures from 14° to 21°C. Specimens 

 ranged in size from 11 to 117 mm SL. It ranked 

 fifth in density within its depth range. 



Prionotus stearnsi was fairly evenly distributed 

 within its depth range, but was slightly more 

 abundant at shallower depths (Figure 3e). Unlike 

 the previous four species, there was no significant 

 relationship between increasing size and increas- 

 ing depth of capture. 



There was no significant difference in catch be- 

 tween bottom types (Table 2). There was, however, 

 a significantly (P<0.001) greater catch during 

 daytime trawling (Table 3). 



Prionotus stearnsi appeared to reach sexual 

 maturity at about 60 mm SL in both sexes. No ripe 

 females were collected during the 1970-71 season 

 and only one female in October and two in 



December of 1969 contained numerous ripe ova 

 (0.6 mm in diameter). 



This species appeared to have different feeding 

 habits between adults and juveniles. The latter 

 (Table 4) fed primarily on small crustaceans (98% 

 of the number of food organisms), the former 

 (Table 5) chiefly on relatively large fishes (usu- 

 ally larger than 25 mm SL; 64% of the number of 

 food organisms). The only other important food 

 among adults was decapod crustaceans. 



DISCUSSION 



Geographic Distribution 



Four of the five species {B. militaris, P. martis, 

 P. roseus, P. stearnsi) have been previously re- 

 corded over the entire northern Gulf of Mexico 

 (Ginsburg 1950; Springer and BuUis 1956; Bullis 

 and Thompson 1965; Burns 1970; Franks et al. 

 1972). Prionotus alatus has been reported almost 

 exclusively from east of the De Soto Canyon, but 

 Ginsburg (1950), Burns (1970), Miller and Kent 

 (1971), and Franks et al. ( 1972, based on the same 

 two specimens examined by Burns) reported 

 small numbers west of the Canyon. Our study 

 confirms this distribution and we conclude that 

 P. alatus is quite rare in the western portion of 

 the northeastern Gulf, where it is replaced by 

 P. paralatus. 



Depth Distribution 



The triglids collected in this study fit into four 

 bathymetric categories: 1) shallow shelf and in- 

 shore species, 2) shallow shelf to midshelf species, 

 3) shallow to deep shelf species, and 4) midshelf to 

 deep shelf species. 



Prionotus martis is a shallow shelf and inshore 

 species. Springer and Bullis (1956) reported it 

 from 200 fathoms (366 m) but we feel that this 

 record is based on either a misidentification or 

 incorrect station data. All other specimens in 

 their paper came from 25 fathoms (46 m) or less. 

 The maximum depth for our study, 44 m (24 

 fathoms), is probably the maximum depth 

 reached by this species. It also enters shallow 

 water, being reported from 6 fathoms or less by 

 Reid (1954), Bulhs and Thompson (1965), Rich- 

 mond (1968), and Hastings (1972). 



Bellator militaris and P. roseus fall into the 

 second category; the maximum depth for both 

 species was about 90 to 100 m. However, B. 



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