Striped mullet, continued 



1 974, Hoese and Moore 1 977). Spawning takes place 

 in offshore marine waters of the Gulf of Mexico over a 

 broad area of the continental shelf (Anderson 1958, 

 Arnold and Thompson 1958, Finucane et al. 1978, 

 Henley and Rauschuber 1981, Nordlie et al. 1982). 

 Adults have been observed spawning during the night 

 40 to 50 miles southeast of the Mississippi River delta 

 at the surface of waters 91 5-1 647 m deep (Arnold and 

 Thompson 1958). Newly spawned eggs have been 

 recovered in plankton trawls 89 to 98 km off the Texas 

 coast in the northwest Gulf of Mexico in waters 131 to 

 1 83 m deep. These eggs were probably spawned over 

 the edge of the continental shelf (Finucane et al. 1 978). 

 Spawners occur in small groups of 3 to 6 fish swimming 

 close to the surface in an erratic manner (Arnold and 

 Thompson 1958). Males stay slightly behind a single 

 female pressing against her and from time to time 

 visibly quiver (Breder 1940, Arnold and Thompson 

 1958). No direct evidence on spawning salinities and 

 temperatures is available, but spawning is apparently 

 unsuccessful at low salinities (Christmas and Waller 

 1973, Martin and Drewry 1978). Hormonal spawning 

 in a laboratory study was best induced at 23.8° to 

 23.5°C, and natural spawning at 21 °C (Kuo et al. 1 973, 

 Sylvester et al. 1975) in salinities ranging from 30 to 

 32%o (Kuo et al. 1 973, Nash et al. 1 974, Sylvester et al. 

 1975). 



Fecundity : Fecundity has been estimated in laboratory 

 studies as being 648 ± 62 to 849 ± 62 eggs/g body 

 weight (Shehadeh et al. 1973, Nash et al. 1974) with 

 recorded releases ranging from 0.76 to 7.2 million 

 eggs/female (Martin and Drewry 1978, Ward and 

 Armstrong 1980). Field studies of Louisiana mullet 

 report individual fecundities of 270,000 to 1,600,000 

 eggs, and relative fecundities of 798 to 2,61 6 eggs per 

 gram body weight, for females in a size range of 290 to 

 445 mm FL (Render et al. 1995). Total individual 

 fecundity correlates with female size, but relative fe- 

 cundity does not. Females generally produce only one 

 set of ova per year (i.e. isochronal) (Render et al. 

 1995). However, it has been suggested that Florida 

 striped mullet may spawn more than once in a season 

 (i.e. heterochronal or batch) (Thomson 1966). Fertili- 

 zation rates in the laboratory have ranged from 53 to 

 95% (Kuo et al. 1973, Shehadeh et al. 1973, Nash et 

 al. 1974). 



Growth and Development 



Egg Size and Embryonic Development : Render et al. 

 (1 995) report that oocyte diameter prior to spawning is 

 0.6 to 0.7 mm, swelling to 0.9 to .95 mm during 

 hydration. Eggsarenonadhesive, spherical, and trans- 

 parent to straw-colored (Martin and Drewry 1978, 

 Ward and Armstrong 1980). Sizes average 0.93 to 

 0.95 mm (Kuo et al. 1 973, Shehadeh et al. 1 973, Nash 

 et al. 1 974, Sylvester et al. 1 975, Finucane et al. 1 978). 



They are characterized by a single large oil globule with 

 a uniform diameter ranging 0.30 to 0.36 mm and 

 averaging 0.33 mm (Kuo et al. 1 973, Nash et al. 1 974, 

 Finucane et al. 1 978). Kuo et al. (1 973) and Nash et al. 

 (1 974) have made thorough descriptions of the striped 

 mullet's embryonic development. Hatching time is 

 temperature dependent. Incubation period is 36 to 38 

 hours after fertilization (AF) at 24°C and 48 to 50 hours 

 AF at 22°C (Kuo et al. 1973, Nash et al. 1974). 



Age and Size of Larvae : The TL at hatching is 2.1 mm 

 to 2.88 mm TL with a reported average of 2.65 ± 0.23 

 mm TL (Kuo et al. 1 973, Nash et al. 1 974, Sylvester et 

 al. 1975, Finucane et al. 1978). At hatching, the yolk 

 sac is ovoid or oblong-ellipsoidal with the oil globule 

 near the center or rear of the yolk sac (Martin and 

 Drewry 1978). The mouth opens on day 2 to 3. Larvae 

 are independently active at this point, and their eyes 

 are sufficiently pigmented for finding food. The yolk 

 sac is absorbed by day 5 (24°C) (Kuo et al. 1 973, Nash 

 et al. 1974, Ward and Armstrong 1980). Most growth 

 during the yolk sac stage occurs during day 1 with larval 

 TL's increasing from 2.65±0.23 mm to 3.36+0.03 mm. 

 The oil globule is still present after the yolk sac is 

 absorbed. Feeding commences at day 5 (24°C) and 

 becomes intensive on day 9 (24°C) or day 14 (22°C) 

 (Kuo et al. 1973). Silvering begins in the abdominal 

 area, spreading dorsally, and is complete on day 25 

 (24°C) when larvae are approximately 10.9 mm TL. 

 This marks the end of the larval stage (Kuo et al. 1 973, 

 Martin and Drewry 1 978). Pre-juveniles are referred to 

 as being in the "querimana" stage (Thomson 1966). 

 The duration of this stage is temperature dependent, 

 and lasts from 30 to 90 days and has a size range of 

 about 11 to 52 mm TL (Anderson 1958, Martin and 

 Drewry 1 978). Growth rates in the wild include: 25 mm 

 SL fish in January of class year increasing to 1 1 6 mm 

 SL in January of class 1 year; 1 8 mm SL fish in October 

 increasing to 65 mm SL by mid-April; and 26 mm TL fish 

 increasing to 88 mm TL from February to July (Gunter 

 1945, Kilby 1949, Hellier 1962). However, reported 

 growth rates for this and other classes vary widely with 

 climate and other factors (Martin and Drewry 1978). 

 Scales begin forming when individuals are about 8 to 

 1 mm SL and 1 1 mm TL, and are complete by 1 2 to 1 4 

 mm SL and 1 8 mm TL (Anderson 1 958, Kuo et al. 1 973, 

 Martin and Drewry 1978). Nostrils double and the full 

 number of fin rays form at 11.9 mm TL (Martin and 

 Drewry 1978). Fish 20 mm SL weigh 2.3 g (Franks 

 1 970). The adipose eyelid is evident at 28 mm TL, and 

 is well developed by 50 mm TL. The third anal ray 

 changes to a hard spine at 41 to 50 mm TL and this 

 marks the end of the prejuvenile stage (Anderson 

 1958, Martin and Drewry 1978). 



Juvenile Size Range : Juveniles have a size range of 

 about 44 to 200 mm SL (Gunter 1 945, Anderson 1 958, 



309 



