Totoaba Totoaba macdonaldi and shortfin corvina Cynoscion parvipinnis, were acclimated and reared together at salinities of 0, 2, 5, 10, 20 and 35 for 56 days. Initial overall mean ± s.d. body masses of 67·6 ± 7·1 g T. macdonaldi and 37·3 ± 3·1 g C. parvipinnis increased to final overall masses of 217·4 ± 30·3 and 96·5 ± 16·5 g, respectively, at the end of the study. Totoaba macdonaldi was not able to tolerate salinities of 0 and 2 and C. parvipinnis of 0. In contrast, both species had 100% survival at salinities ≥ 10. Somatic growth was highest not at natural seawater salinity of 35, but at 10. Plasma osmolality ranged from 172·5 to 417·0 mOsmol kg for T. macdonaldi and from 207·0 to 439·5 mOsmol kg for C. parvipinnis and varied in direct proportion to salinity. The estimated isosmotic salinities of T. macdonaldi and C. parvipinnis were 12·3 and 13·4, respectively. Cynoscion parvipinnis reared at two had significantly lower plasma lysozyme activity (95·0 Units ml ) than fish held at salinities from 5 to 35 (ranging from 215·0 to 355·0 Units ml ), but without clear trends over this range. Blood neutrophil oxidative radical production (NBT) (ranging from 3·9 to 6·7 mg ml ) had some significant differences among salinities, but these did not follow a clear pattern. For T. macdonaldi, neither lysozyme activity nor NBT was affected by salinity. Ash content of whole fishes varied directly and moisture content inversely, with salinity for both species.

Limbaugh?s damselfish, Chromis limbaughi Greenfield & Woods, 1980, is endemic to the Gulf of California, and one of the five most exploited species for the aquarium trade in this region. C. limbaughi is a gonochoristic, gregarious and territorial species without sexual dimorphism that inhabits rocky, sheltered areas. Development of captive breeding techniques for this species would not only ensure a continued supply of fish for the commercial trade, but perhaps more importantly, it would also alleviate fishing pressure and support stock enhancement. Thus, as a first step towards achieving these goals, in this work, we investigated some aspects of the reproductive biology of C. limbaughi. Seasonal fish samplings, with a total of eighty-nine fish caught in one year, were carried out at San Esteban Island, Gulf of California, Mexico. The reproductive season of C. limbaughi extends, at least, from May to September. A new maximum standard length of 10.5 cm is reported for this species. The estimated size at first sexual maturity was 7.90 cm for males and 7.59 cm for females. For both male and female gonads, the major constituent fatty acids were palmitic acid, stearic acid, oleic acid, docosahexaenoic acid, eicosapentaenoic acid and arachidonic acid. The water-quality conditions under which maturation of C. limbaughi took place were measured, and should prove useful for the management of broodstock in captivity.

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