Pink shrimp, continued 



postlarva in 2 to 3 weeks depending on the tempera- 

 ture and location. Metamorphosis from protozoea to 

 postlarva occurs in 15 days at 26°C, and in 25 days at 

 21°C(Ewald 1965). 



Juvenile Size Range : Reported juvenile growth rates 

 vary from 7 to 52 mm/month (Williams 1 955a, Eldred et 

 al. 1 961 , Iversen and Jones 1 961 ), and subadults and 

 adults grow approximately to 22 mm/month (Costello 

 and Allen 1960, Iversen and Jones 1961, McCoy and 

 Brown 1 967). Sexual maturity occurs at 85 mm TL for 

 females and 74 mm TL for males (Dobkin 1 961 , Bielsa 

 etal. 1983). 



Age and Size of Adults : The average sizes of large 

 male and female pink shrimp are 1 70 mm and 210 mm 

 TL, respectively. The average maximum age is 83 

 weeks with an absolute maximum age of 2 years 

 (Bielsa etal. 1983). 



Food and Feeding 



Trophic Mode : Pink shrimp are omnivorous consumers 

 in marine and estuarine systems (Bielsa et al. 1983). 

 Larvae in the naupliar stages do not feed, but first 

 protozoea were observed to begin feeding immedi- 

 ately when food became available (Ewald 1 965). Lar- 

 vae and postlarvae feed on various plankton species. 

 Juveniles and adults are opportunistic and forage 

 primarily at night, on benthic prey, in shallow grass 

 beds (Bielsa et al. 1983, Williams 1984, Nelson and 

 Capone 1990, Schmidt 1993). 



Food Items : Larvae raised in hatchery conditions are 

 fed various cultures of algae initially, and increasing 

 amounts of brine shrimp nauplii as they became older 

 (Ewald 1 965). Typical juvenile and adult prey includes 

 nematodes, polychaetes, ostracods, copepods, di- 

 noflagellates, annelids, gastropods, mollusks, filamen- 

 tous green and blue-green algae, vascular detritus, 

 and inorganic material (Bielsa et al. 1983, Williams 

 1984, Nelson and Capone 1990, Schmidt 1993). 



Biological Interactions 



Predation : Many inshore fish species utilize the pink 

 shrimp in their diet. Sport fishes such as snook, spotted 

 seatrout, and gray snapper feed heavily on this spe- 

 cies, but it is found in varying amounts in the diets of 

 other fishes. These include lemon shark (Negaprion 

 brevirostris), hardhead catfish, gafftopsail catfish (Bagre 

 marinus), pinfish, pigfish (Orthopristis chrysoptera), 

 sheepshead, crevalle jack, red drum, code goby, Span- 

 ish mackerel, and red snapper (Lutjanus campechanus) 

 (Kemp 1949, Miles 1949, Springer and Woodburn 

 1 960, Odum 1 971 , Carr and Adams 1 973, Overstreet 

 and Heard 1 978, Overstreet and Heard 1 982, Saloman 

 and Naughton 1984, Sheridan et al. 1984, Schmidt 

 1986, Harrigan et al. 1989, Heftier 1989). Many reef 



species, such as mutton snapper (Lutjanus analis), red 

 grouper (Epinephelus morio), black grouper 

 (Mycteroperca bonaci), and even pelagic species such 

 as king mackerel (Scomberomorus cavalla) have been 

 found to prey on pink shrimp (Bielsa et al. 1983). In 

 addition, several birds prey on this species. These 

 include wading birds, feeding opportunistically in coastal 

 areas and seabirds foraging in mixed species flocks on 

 concentrations of prey. Pink shrimp are probably an 

 easy target for diving seabirds during periods of con- 

 gregated movement. This species has also been 

 found in the stomachs of some marine mammals 

 (Tursiops truncatus and Stenella coeruleoalba), and 

 may possibly be a prey item of marine reptiles (Bielsa 

 et al. 1983). The bay squid (Lolliguncula brevis) is 

 known to consume penaeid shrimp, and may include 

 the pink shrimp as a prey item (Hargis 1979). 



Factors Influencing Populations : Disease is second 

 only to predation and periodic physical catastrophes in 

 limiting numbers of penaeid shrimps in nature (Couch 

 1 978). A significant number of pink and brown shrimp 

 in the Gulf of Mexico may be infected with the 

 Baculoviruspenaei (BP) virus (Overstreet 1 994, Stuck 

 pers. comm.). This virus is highly pathogenic to the 

 early life stages of penaeid shrimp (Lightner and 

 Redman 1 991 ), and it may be responsible for epizootic 

 mortalities of pink shrimp (Couch et al. 1 975). Penaeid 

 shrimp infected with symbiotic organisms may be weak- 

 ened and more susceptible to mortality in waters with 

 low DO (Overstreet 1978). Distribution, abundance, 

 and recruitment of the pink shrimp may be limited by 

 salinity, freshwater runoff , temperature, seagrass habi- 

 tat, and substrate (Williams 1 965, Bielsa 1 983, Browder 

 1 985, Hettler 1 992, Schmidt 1 993). Recruitment over- 

 fishing by commercial shrimpers does not appear to be 

 a problem for this species, but annual catch is man- 

 aged to prevent the parent stock from falling below the 

 level considered necessary to maintain recruitment 

 (Nance 1989, Klima et al. 1990). Environmental 

 changes may cause variable recruitment (Klima et al. 

 1 990, Sheridan 1 996). The pink shrimp may compete 

 for or be displaced by brown shrimp from habitats. This 

 species can be difficult to distinguish from the brown 

 shrimp, often resulting in unreliable data (Sheridan 

 pers. comm.). 



68 



