Fisheries Research 147 (2013) 150–153 Contents lists available at SciVerse ScienceDirect Fisheries Research jou rn al hom ep age: www.elsevier.com/locate/fishres Intrinsic rebound potential of the endangered (Totoaba macdonaldi) population, endemic to the Gulf of California, México J. Fernando Márquez-Farías a,b,∗ , F. Jorge Rosales-Juárez b a Facultad de Ciencias del Mar, Universidad Autónoma de Sinaloa, Paseo Claussen S/N, Col. Los Pinos. Mazatlán, Sinaloa, México CP 82000, México b Ecosistemas Costeros Sustentables, A.C. (ECOS). Río de la Plata 409, Col. Las Gaviotas, Mazatlán, Sinaloa, México CP 82110, México a r t i c l e i n f o Article history: Received 8 March 2013 Received in revised form 28 May 2013 Accepted 30 May 2013 Keywords: Demography Rebound potential Endanger Artisanal fishery Bycatch Gulf of California a b s t r a c t The population of totoaba, Totoaba macdonaldi, an endangered, endemic, large sciaenid in the Gulf of California collapsed from over exploitation and habitat degradation. The fishery stopped in 1975 and the current status of its abundance recovery prospects is uncertain. The intrinsic rebound potential of totoaba was calculated using an alternative demographic model and assuming zero fishing mortality after the total fishing prohibition was applied. The value can be compared with that for other species. The rate of rebound estimated for totoaba (r 2M = 0.055) confirms its low resilience to fishing. Factors that influence recovery of the totoaba include illegal fishing, its discrete distribution, and its strong fidelity to the delta of Colorado River for spawning and as a nursery area. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Populations of long-lived marine animals have life history pat- terns that generally include low fecundity, late maturity, slow growth, and also variable and infrequent recruitment (Musick, 1999). These characteristics of life history classify them as K- selected (MacArthur and Wilson, 1967) and make their populations susceptible to rapid decline even under moderate fishing (Punt and Smith, 1999). In addition, some K-selected species may also possess other particularities, such as discrete distribution, sex/size segregation and aggregation, vulnerable schooling behavior, and endemism that make them extremely vulnerable to commercial exploitation. Critical habitats are also often a characteristic (e.g., nursery areas), and human induced degradation and alteration of those habitats can be particularly threatening. The ability of a long- lived species to withstand or recover from anthropogenic assaults can be determined by demographic analysis (Stevens, 1999) if suf- ficient information on life history, such as age, growth, mortality, and reproduction is available (Cailliet, 1992; Punt and Smith, 1999; Musick, 1999). The totoaba Totoaba macdonaldi (Gilbert, 1890), a large sciaenid endemic to the Gulf of California (Fig. 1), forms large schools of ∗ Corresponding author at: Facultad de Ciencias del Mar, Universidad Autónoma de Sinaloa, Paseo Claussen S/N, Col. Los Pinos. Mazatlán, Sinaloa, México CP 82000, México. Tel.: +52 669 1809827. E-mail address: fermqz@yahoo.com (J.F. Márquez-Farías). migratory fish that depend on the upper Gulf of California for spawning and as a nursery ground for juveniles (Arvizu and Chavez, 1972; Flanagan and Hendrickson, 1976; Cisneros-Mata et al., 1995). The totoaba is a valuable market species and its fishery devel- oped in response to the demand for its gas bladder which was exported to China and the United States. The rest of the fish was wasted or poorly consumed by local fishers from “Golfo de Santa Clara” village in the upper Gulf of California. According to offi- cial statistics, the peak of fishery production was 2300 t in 1942, with the last official record near 60 t in 1975 (Fig. 2). The biomass of the totoaba was almost completely removed in 38 years, from 1937 to 1975, the year the Mexican government imposed a per- manent restriction on totoaba fishing (Flanagan and Hendrickson, 1976). In 1976, the totoaba was listed by the Convention of Inter- national Trade of Endangered Species (Barrera-Guevara, 1990), and was declared endangered by the United States in 1979 (U.S. Federal Register 44 1979). Rosales-Juárez and Ramírez-González (1987) reviewed the totoaba fishery and hypothesized reasons for the collapse of the fishery, which are, among others, habitat alteration by reduced flows and poor water quality of the Col- orado River, over-fishing of adults by the artisanal gill net fishery, bycatch of juveniles by the shrimp trawling fishery, and sport fishing (Berdegué, 1955; Flanagan and Hendrickson, 1976; Rosales- Juárez and Ramírez-González, 1987; Cisneros-Mata et al., 1995, 1997). Currently, gill net fishing for totoaba remains illegal, though incipient catches continue (Fernando Márquez, pers. obs.). Small juveniles are still taken as bycatch in the shrimp-trawling fishery that operates in the northern Gulf of California (García-Caudillo 0165-7836/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.fishres.2013.05.009