Thermal tolerance and resistance of the northern anchovy, Engraulis mordax

Journal Article · Thu Apr 01 04:00:00 EST 1976 · Fish. Bull.; (United States)

OSTI ID:7326261

Brewer, G D

An experimental, flow-through seawater system, constructed to maintain juvenile and adult northern anchovy, Engraulis mordax, and rear embryos and larvae through yolk-sac absorption under controlled temperature and photoperiod regimes, was used to determine aspects of thermal tolerance, resistance, rates of acclimation, and some effects of temperature on the development and growth of the anchovy. Thermal tolerance was determined for juvenile and adult fish, acclimated to six constant temperatures between 8/sup 0/ and 28/sup 0/C. Thermal resistance (minutes until death for fish exposed to a lethal temperature) was independent of photoperiod and fish size; however, females proved more resistant than males, and resistance decreased at night. Acclimation (as measured by resistance) from 12/sup 0/ to 20/sup 0/C was nearly complete after 2-day exposure to the higher temperature, acclimation from 20/sup 0/ to 12/sup 0/C was nearly complete after 5-day exposure to the lower temperature. Fish subjected to fluctuating water temperatures between 12/sup 0/ and 20/sup 0/C proved less resistant to cold than a 12/sup 0/C (constant) acclimated group and less resistant to heat than a 20/sup 0/C (constant) acclimated group. Thermal tolerance was determined for larvae in the yolk-sac stage, acclimated to four constant temperatures between 12/sup 0/ and 24/sup 0/C. Although hatching occurred at temperatures as high as 29.5/sup 0/C and as low as 8.5/sup 0/C, the percentage of normally developed larvae equaled that of controls incubated at 16/sup 0/C) only between temperatures of 27.0/sup 0/ and 11.5/sup 0/C. Embryos in the blastodisc stage proved most sensitive to acute temperature increases when compared to embryos in the blastopore closure stage and larvae in the yolk-sac stage. These same three stages proved insensitive to acute temperature decreases to 0.5/sup 0/C for 60-min exposure periods. Temperature is discussed in relation to anchovy distribution and survival under natural and artificially created thermal conditions.

• Research Organization: Univ. of Southern California, Los Angeles
• OSTI ID: 7326261
• Journal Information: Fish. Bull.; (United States), Journal Name: Fish. Bull.; (United States) Vol. 74:2; ISSN FSYBA
• Country of Publication: United States
• Language: English

Related Subjects

560205* -- Thermal Effects-- Vertebrates-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ADULTS
ANIMALS
AQUATIC ORGANISMS
BIOLOGICAL ADAPTATION
DISTRIBUTION
FISHES
GROWTH
HATCHING
HYDROGEN COMPOUNDS
JUVENILES
LARVAE
OXYGEN COMPOUNDS
SEAWATER
SURVIVAL TIME
TEMPERATURE EFFECTS
VERTEBRATES
WATER