Seasonal depth distribution of the 

 crystal shrimp, Penaeus brevirostris 

 (Crustacea: Decapoda, Penaeidae), 

 and its possible relation to 

 temperature and oxygen 

 concentration off southern 

 Sinaloa, Mexico 



Hector Garduno-Argueta 



Instituto Nacional de la Pesca 



Chilpancmgo #70. col. Hipodromo Condesa, Mexico, D.F. 



Jose A. Calderon-Perez 



Estaci6n Mazatlan. Instituto de Gencias del Mary Limnologia. U.N. A.M. 

 Apdo. Postal 811, Mazatlan, Sinaloa, Mexico. C.P 82000 



With an estimated value of 30 mil- 

 lion U.S. dollars, red or crystal 

 shrimp, Penaeus brevirostris, is the 

 sixth most important fishery re- 

 source in Mexico (Edwards, 1978; 

 Rodriguez de la Cruz, '1981; Her- 

 nandez-Carballo, 1988). However, 

 until recently very little was known 

 about its general biology, ecology, 

 and seasonal variation in relative 

 abundance. 



Penaeus brevirostris is a species 

 limited to the eastern tropical Pa- 

 cific off northern Sinaloa, Mexico, 

 to southwest of Cabo Blanco, Peru, 

 and Islas Galapagos (Perez-Far- 

 fante, 1988). In Mexico, it is nor- 

 mally fished in two areas: from 

 southern Sinaloa to northern Nay- 

 arit and in the Gulf of Tehuantepec 

 (Edwards, 1978; Hernandez-Car- 

 ballo, 1988). Penaeus brevirostris 

 occupies a wide range of depths. 

 Postlarvae are found near the shore 

 and in coastal lagoons (Calderon- 

 Perez and Poli, 1987). Preadults 

 and adults have been found at 

 depths of 45-90 m off Mexico (Rodri- 

 guez de la Cruz, 1981; Hendrickx et 

 al., 1984; Chapa-Saldana 1 ) and Peru 



(Cobo and Loesch, 1966) and at 3 

 m in estuarine channels (esteros) 

 in Ecuador (Loesch and Avila 2 ). The 

 deepest record of crystal shrimp is 

 183 m (Perez-Farfante, 1988). In 

 spite of its rather wide depth dis- 

 tribution, P. brevirostris is usually 

 found deeper than.P stylirostris (es- 

 tuarine and marine to 27 m, rarely 

 to 45 m; Rodriguez de la cruz, 1981; 

 Hendrickx, 1986; Perez-Farfante, 

 1988), P. vannamei (estuarine and 

 marine to 36 m) (Rodriguez de la 

 Cruz, 1981; Hendrickx, 1986) and 

 P. californiensis (estuarine and ma- 

 rine to 50 m, rarely to 180 m) 

 (Perez-Farfante, 1988). Occasion- 

 ally, it is found c o-existing with the 

 latter (Chapa-Saldana 1 ). In two 

 separate fishing surveys during the 

 closed (nonfishing) season, the spe- 

 cies was not found on traditional 

 trawling grounds off Sinaloa and 

 Nayarit (Barreiro and Lopez-Guer- 

 rero, 1972; Magallon-Barajas and 

 Jacquemin-Poulet, 1976). 



The purpose of this study is to de- 

 termine whether the distribution of 

 P. brevirostris varies seasonally 

 with respect to depth (presumably, 



because of the bathymetric move- 

 ments of the species) and to relate 

 its distribution to temperature and 

 oxygen variation near the bottom. 



Material and methods 



The study area (Fig. 1) lies at the 

 entrance of the Gulf of California 

 (Alvarez-Borrego, 1983) off the 

 mouths of the Piaxtla River to the 

 north (23°42'N, 106°49'W) and the 

 Teacapan-Agua Brava Lagoon com- 

 plex to the south (22°32'N, 105°45'W). 

 It has been described as a transi- 

 tional zone that has a complex and 

 dynamic structure (Alvarez-Bor- 

 rego, 1983). At the surface, there 

 are three different types of water: 

 1) cold California Current water of 

 low salinity (S <34.6 ppt) which 

 flows southward along the west 

 coast of Baja California; 2) warm 

 eastern tropical Pacific water of 

 intermediate salinity (34.65 ppt < 

 S >34.85 ppt) which flows into the 

 area from the southeast; and 3) 

 warm, highly saline (S >34.9 ppt) 

 Gulf of California water (Roden and 

 Groves, 1959; Stevenson 1970; 

 Alvarez-Borrego, 1983). This region 

 experiences upwelling events dur- 

 ing the spring (Roden, 1964; Roden 

 and Groves, 1959; Alvarez-Borrego 

 and Schwartzlose, 1979). The oxy- 

 gen content in the upper 100 m 

 layer is greater than 1 mL/L; be- 

 low 150 m the oxygen concentration 

 falls to less than 0.5 mL/L and at 

 intermediate depths (500-1,100 m) 

 oxygen may be undetectable by the 

 Winkler method (Alvarez-Borrego 

 et al., 1978). 



1 Chapa-Saldana, H. 1956. La distribution 

 comercial de los camarones del noroeste de 

 Mexico y el problema de las artes fijas de 

 pesca. Dir. Gral. de Pesca e Industrias 

 Conexas, Sria. de Marina, Mexico, D.F., 87 p. 



2 Loesch, H., and Q. Avila. 1966. Obser- 

 vaciones sobre le pesqueria de camarones 

 juveniles en dos esteros de la costa de Ec- 

 uador. Bol. Cient. y Teen. INP del Ecua- 

 dor. 1, 30 p. 



Manuscript accepted 29 August 1994. 

 Fishery Bulletin:397-402 (1995). 



397 



