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Effects of Salinity on Eggs, Larvae, and Juveniles of Blacknose Silversides from Lake Chapala, Mexico
Author(s) -
MartínezPalacios Carlos A.,
SalgadoGarcía Rosa L.,
Racotta Ilie S.,
CamposMendoza Antonio,
Ross Lindsay G.
Publication year - 2008
Publication title -
north american journal of aquaculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 41
eISSN - 1548-8454
pISSN - 1522-2055
DOI - 10.1577/a06-026.1
Subject(s) - salinity , biology , hatching , hatchery , larva , zoology , fishery , ecology , fish <actinopterygii>
Abstract The salinity tolerance of eggs, larvae, and juveniles of blacknose silverside Chirostoma promelas was investigated with the objective of optimizing hatchery practice. A high proportion (>90%) of eggs became eyed in all salinities. Eggs exposed to an instantaneous change of salinity hatched best at 0–15 practical salinity units (psu; 1 psu ≈ 1‰); reduced hatching occurred at 20 psu and no hatching occurred at 25–35 psu. By contrast, eggs exposed after 5 d to a slow change of salinity to freshwater over 48 h also hatched well at 0–15 psu, but they hatched at higher salinities as well. Fungal infections of eggs were greatest at 0 and 5 psu. Larvae exposed to an instantaneous change of salinity (0–25 psu) had the best survival rates at salinities of 0 psu (83%) and 5 psu (87%), but lower survival was obtained at 10 psu (49%) and 15 psu (22%) after 144 h. At 20 and 25 psu, larval mortality was 90% and 100%, respectively, after 48 h. In contrast, larvae exposed to a slow change of salinity over 48 h showed a higher salinity tolerance (43% survival at 20 psu), although higher salinities killed the fish. Juveniles had a high tolerance (100% survival) to a slow salinity change over 48 h at 0–25 psu. After 90 d, survival was best at 5–20 psu, optimal growth occurring at 5, 10, and 15 psu. Mortality was 100% in fish reared in freshwater after 75 d of culture, possibly a result of the high stress at this salinity. The osmolarity of muscle tissue of juveniles was not significantly different ( P > 0.05) between trials, indicating efficient internal ionic regulation at all salinities. The wide salinity tolerance of blacknose silverside is clearly beneficial for its management and culture.