Hardhead catfish, continued 



been noted in some inshore areas during the spawning 

 season (Springer and Woodburn 1960, Dugas 1970). 



Spawning females have slightly everted hemorrhagic 

 genital openings (Gunter 1947), and enlarged pelvic 

 fins which may serve to enhance fertilization (Lee 

 1 937). Females with enlarging pelvic fins are seen as 

 early as March and through July and do not totally 

 disappear until after October (Gunter 1945). Motile 

 sperm in males has been noted from early March until 

 the middle of July (Ward 1 957). It has been suggested 

 that eggs are initially deposited in sandy depressions. 

 The males fertilize the eggs and then pick them up into 

 their mouths to brood them (Gunter 1 947, Jones et al. 

 1978). Brooding males have enlarged branchial and 

 buccal cavities to accommodate eggs or larvae, and 

 their mouths are hemorrhagic in appearance (Lee 

 1937, Reid 1955, Zimmerman 1969). Brooding males 

 are observed from May to August (Lee 1937, Gunter 

 1945, Gunter 1947, Reid 1955, Breuer 1957, 

 Zimmerman 1969, Dugas 1970, Bryan 1971, Christ- 

 mas and Waller 1 973, Swift et al. 1 977). The numbers 

 of eggs or larvae reported found in brood males range 

 from 1 to 48 and do not appear to be related to the 

 length of the male (Lee 1937, Gunter 1945, Gunter 

 1 947, Reid 1 955, Reid 1 957). Males do not feed during 

 the brooding period which lasts about 60 days (Lee 

 1937, Gunter 1947, Jones et al. 1978). 



Fecundity : Females produce 1 4 to 64 mature ova each 

 season, along with numerous small, nonfunctional 

 eggs. The left ovary is slightly larger and typically has 

 3 to 6 more eggs than the right (Lee 1 937, Gunter 1 945, 

 Gunter 1947, Reid 1955, Ward 1957, Jones et al. 

 1 978). Females may spawn more than once a season 

 (Gunter 1945). 



Growth and Development 



Egg Size and Embryonic Development : Eggs are de- 

 mersal. Ripe ovarian eggs are greenish, slightly oval 

 or elliptical, and measure 12-19 mm in diameter (Lee 

 1 937, Gunter 1 947, Reid 1 955, Ward 1 957, Jones et al. 

 1 978). Many small nonfunctional eggs are attached to 

 ripe eggs and to each other by a thin, colorless, 

 adhesive film that is lost as development proceeds. 

 Non-functional eggs may serve as food for males that 

 fast while brooding (Gunter 1947, Ward 1957). Eggs 

 reach the gastrula stage after about 29 hours, and 

 hatching probably occurs in about 30 days (Ward 

 1957, Jones etal. 1978). 



Age and Size of Larvae : Hatching size ranges from 29 

 to 45 mm TL and occurs primarily in June (Bryan 1 971 , 

 Gallaway and Strawn 1974, Cornelius 1984). The 

 duration of the larval stage ranges from about 2 to 4 

 weeks in the wild and up to 55 days under laboratory 

 conditions (Jones et al. 1 978). Although mouth brooded 



young are considered to be in the larval stage, their fin 

 ray complement is complete before yolk absorption, 

 and therefore, a true larval stage is not considered to 

 exist (Jones et al. 1 978). The yolk supply is used up by 

 50 mm TL (Gunter 1945). 



Juvenile Size Range : Juveniles are released by male 

 parents from June to August (Swingle 1 971 , Christmas 

 and Waller 1973, Gallaway and Strawn 1974). The 

 standard length (SL) of juveniles when released ranges 

 from 33 to 58 mm (Gallaway and Strawn 1 974) and 41 

 to 62 mmTL (Gunter 1945, Swingle 1971, Christmas 

 and Waller 1973). Juveniles in the wild have been 

 observed to grow 10 mm/month from July to October; 

 however, cooler watertemperatures drastically reduce 

 the growth rate during winter months (Christmas and 

 Waller 1973). 



Age and Size of Adults : Minimum sizes noted for 

 sexually mature adults are 1 35 mm TL and 1 26 SL for 

 females, and 142 mm SL and 201 mm TL for brood 

 males (Lee 1937, Gunter 1947). Maximum reported 

 sizes are 635 mm TL and 330 mm SL (Reid 1955, 

 Barrett et al. 1978) with average sizes of 110 mm TL 

 and fork lengths (FL) of 100 to 160 mm (Perret et al. 

 1 971 , Chittenden and McEachron 1 976). Adults rarely 

 exceed 1.154 kg in weight (Gallaway and Strawn 

 1974). The average life span is 2 to 3 years (Swingle 

 1971, Chittenden and McEachron 1976). 



Food and Feeding 



Trophic mode : This species is carnivorous throughout 

 its development. Both juveniles and adults are oppor- 

 tunistic, nocturnal bottom feeders utilizing a wide range 

 of feeding modes such as scavenging, carnivory, and 

 ectoparasitism (Miles 1949, Darnell 1958, Hildebrand 

 1958, Hellier 1962, Hoese 1966, Harris and Rose 

 1968, Odum 1971, Diener et al. 1974, Dugas 1975, 

 Benson 1982). 



Food Items : The hardhead catfish feeds primarily on 

 crustaceans (shrimp and crabs), and insects. Molluscs 

 are also an important diet item. This species may pass 

 through three feeding stages in its development: zoop- 

 lankton, especially copepods, are most important for 

 individuals <100 mm TL; benthic micro-invertebrates 

 are most important for individuals between 100 and 

 200 mm TL; crabs and fishes gradually assume impor- 

 tance in fish >200 mm TL (Darnell 1 958). Specific diet 

 items that have been reported include: bottom debris 

 and detritus; plant tissue, algae, polychaetes, gastro- 

 pods, bivalves (Rangia cuneata and Congeria 

 leucophaeta), ostracods, isopods, copepods, cirripedia, 

 amphipods, mysids, penaeid shrimp including brown 

 shrimp and pink shrimp, grass shrimp, blue crabs, 

 xanthid (mud) crabs, insects, arachnids, menhaden, 

 anchovies, silversides, mullets, juvenile hardhead cat- 



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