The effects of environmental factors on the embryonic survival of the Patagonian squid Loligo gahi

CINITI, ANA; BARÓN, PEDRO J.; RIVAS, ANDRÉS, L.

JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY

Elsevier

Año: 2004 p. 225 - 240

0022-0981

Seawater temperature and salinity are environmental variables that impose physiological limits for the embryonic development of marine invertebrates. For cephalopod species, these limits have rarely been established. This work presents experimental results on the embryonic survival of the Patagonian squid Loligo gahi, which is the last decades’ most important loliginid species in terms of volume of commercial catches worldwide, as a function of seawater temperature and salinity. Reference magnitudes of surface seawater temperature and salinity within the area of distribution of the species were explored by analysis of satellite databases and published information. Embryos were incubated under eight constant regimes of temperature within 4–22 jC and four constant salinity regimes within 20–34.33x (12 jC). Also, to determine the effects of sudden temperature changes on embryonic survival, embryos were incubated at four variable regimes of temperature, with thermal shifts (6-day long 2-jC magnitude alterations of the incubation temperature) applied both at early and late stages of embryonic development. Embryonic survival was zero in incubations at constant temperature regimes embryonic development. Embryonic survival was zero in incubations at constant temperature regimes survival, embryos were incubated at four variable regimes of temperature, with thermal shifts (6-day long 2-jC magnitude alterations of the incubation temperature) applied both at early and late stages of embryonic development. Embryonic survival was zero in incubations at constant temperature regimes embryonic development. Embryonic survival was zero in incubations at constant temperature regimes 20–34.33x (12 jC). Also, to determine the effects of sudden temperature changes on embryonic survival, embryos were incubated at four variable regimes of temperature, with thermal shifts (6-day long 2-jC magnitude alterations of the incubation temperature) applied both at early and late stages of embryonic development. Embryonic survival was zero in incubations at constant temperature regimes embryonic development. Embryonic survival was zero in incubations at constant temperature regimes survival, embryos were incubated at four variable regimes of temperature, with thermal shifts (6-day long 2-jC magnitude alterations of the incubation temperature) applied both at early and late stages of embryonic development. Embryonic survival was zero in incubations at constant temperature regimes embryonic development. Embryonic survival was zero in incubations at constant temperature regimes commercial catches worldwide, as a function of seawater temperature and salinity. Reference magnitudes of surface seawater temperature and salinity within the area of distribution of the species were explored by analysis of satellite databases and published information. Embryos were incubated under eight constant regimes of temperature within 4–22 jC and four constant salinity regimes within 20–34.33x (12 jC). Also, to determine the effects of sudden temperature changes on embryonic survival, embryos were incubated at four variable regimes of temperature, with thermal shifts (6-day long 2-jC magnitude alterations of the incubation temperature) applied both at early and late stages of embryonic development. Embryonic survival was zero in incubations at constant temperature regimes embryonic development. Embryonic survival was zero in incubations at constant temperature regimes survival, embryos were incubated at four variable regimes of temperature, with thermal shifts (6-day long 2-jC magnitude alterations of the incubation temperature) applied both at early and late stages of embryonic development. Embryonic survival was zero in incubations at constant temperature regimes embryonic development. Embryonic survival was zero in incubations at constant temperature regimes 20–34.33x (12 jC). Also, to determine the effects of sudden temperature changes on embryonic survival, embryos were incubated at four variable regimes of temperature, with thermal shifts (6-day long 2-jC magnitude alterations of the incubation temperature) applied both at early and late stages of embryonic development. Embryonic survival was zero in incubations at constant temperature regimes embryonic development. Embryonic survival was zero in incubations at constant temperature regimes survival, embryos were incubated at four variable regimes of temperature, with thermal shifts (6-day long 2-jC magnitude alterations of the incubation temperature) applied both at early and late stages of embryonic development. Embryonic survival was zero in incubations at constant temperature regimes embryonic development. Embryonic survival was zero in incubations at constant temperature regimes Loligo gahi, which is the last decades’ most important loliginid species in terms of volume of commercial catches worldwide, as a function of seawater temperature and salinity. Reference magnitudes of surface seawater temperature and salinity within the area of distribution of the species were explored by analysis of satellite databases and published information. Embryos were incubated under eight constant regimes of temperature within 4–22 jC and four constant salinity regimes within 20–34.33x (12 jC). Also, to determine the effects of sudden temperature changes on embryonic survival, embryos were incubated at four variable regimes of temperature, with thermal shifts (6-day long 2-jC magnitude alterations of the incubation temperature) applied both at early and late stages of embryonic development. Embryonic survival was zero in incubations at constant temperature regimes embryonic development. Embryonic survival was zero in incubations at constant temperature regimes survival, embryos were incubated at four variable regimes of temperature, with thermal shifts (6-day long 2-jC magnitude alterations of the incubation temperature) applied both at early and late stages of embryonic development. Embryonic survival was zero in incubations at constant temperature regimes embryonic development. Embryonic survival was zero in incubations at constant temperature regimes 20–34.33x (12 jC). Also, to determine the effects of sudden temperature changes on embryonic survival, embryos were incubated at four variable regimes of temperature, with thermal shifts (6-day long 2-jC magnitude alterations of the incubation temperature) applied both at early and late stages of embryonic development. Embryonic survival was zero in incubations at constant temperature regimes embryonic development. Embryonic survival was zero in incubations at constant temperature regimes survival, embryos were incubated at four variable regimes of temperature, with thermal shifts (6-day long 2-jC magnitude alterations of the incubation temperature) applied both at early and late stages of embryonic development. Embryonic survival was zero in incubations at constant temperature regimes embryonic development. Embryonic survival was zero in incubations at constant temperature regimes jC and four constant salinity regimes within 20–34.33x (12 jC). Also, to determine the effects of sudden temperature changes on embryonic survival, embryos were incubated at four variable regimes of temperature, with thermal shifts (6-day long 2-jC magnitude alterations of the incubation temperature) applied both at early and late stages of embryonic development. Embryonic survival was zero in incubations at constant temperature regimes embryonic development. Embryonic survival was zero in incubations at constant temperature regimes survival, embryos were incubated at four variable regimes of temperature, with thermal shifts (6-day long 2-jC magnitude alterations of the incubation temperature) applied both at early and late stages of embryonic development. Embryonic survival was zero in incubations at constant temperature regimes embryonic development. Embryonic survival was zero in incubations at constant temperature regimes x (12 jC). Also, to determine the effects of sudden temperature changes on embryonic survival, embryos were incubated at four variable regimes of temperature, with thermal shifts (6-day long 2-jC magnitude alterations of the incubation temperature) applied both at early and late stages of embryonic development. Embryonic survival was zero in incubations at constant temperature regimes embryonic development. Embryonic survival was zero in incubations at constant temperature regimes jC magnitude alterations of the incubation temperature) applied both at early and late stages of embryonic development. Embryonic survival was zero in incubations at constant temperature regimes V 5j and at 22 jC, low at 6 jC, and high within 8–20 jC. A function was fitted by nonlinear regression to relate embryonic survival and mean incubation temperature. Thermal shifts applied in incubations at 20–22–20 jC variable regime of temperature provoked low embryonic survival compared to that observed in incubation at 20 jC constant regime. Embryonic survival was zero in incubations conducted at 20.0x and 34.3x salinity, and high at 26.4x and 32.8x salinities. incubations conducted at 20.0x and 34.3x salinity, and high at 26.4x and 32.8x salinities. compared to that observed in incubation at 20 jC constant regime. Embryonic survival was zero in incubations conducted at 20.0x and 34.3x salinity, and high at 26.4x and 32.8x salinities. incubations conducted at 20.0x and 34.3x salinity, and high at 26.4x and 32.8x salinities. regression to relate embryonic survival and mean incubation temperature. Thermal shifts applied in incubations at 20–22–20 jC variable regime of temperature provoked low embryonic survival compared to that observed in incubation at 20 jC constant regime. Embryonic survival was zero in incubations conducted at 20.0x and 34.3x salinity, and high at 26.4x and 32.8x salinities. incubations conducted at 20.0x and 34.3x salinity, and high at 26.4x and 32.8x salinities. compared to that observed in incubation at 20 jC constant regime. Embryonic survival was zero in incubations conducted at 20.0x and 34.3x salinity, and high at 26.4x and 32.8x salinities. incubations conducted at 20.0x and 34.3x salinity, and high at 26.4x and 32.8x salinities. 5j and at 22 jC, low at 6 jC, and high within 8–20 jC. A function was fitted by nonlinear regression to relate embryonic survival and mean incubation temperature. Thermal shifts applied in incubations at 20–22–20 jC variable regime of temperature provoked low embryonic survival compared to that observed in incubation at 20 jC constant regime. Embryonic survival was zero in incubations conducted at 20.0x and 34.3x salinity, and high at 26.4x and 32.8x salinities. incubations conducted at 20.0x and 34.3x salinity, and high at 26.4x and 32.8x salinities. compared to that observed in incubation at 20 jC constant regime. Embryonic survival was zero in incubations conducted at 20.0x and 34.3x salinity, and high at 26.4x and 32.8x salinities. incubations conducted at 20.0x and 34.3x salinity, and high at 26.4x and 32.8x salinities. jC variable regime of temperature provoked low embryonic survival compared to that observed in incubation at 20 jC constant regime. Embryonic survival was zero in incubations conducted at 20.0x and 34.3x salinity, and high at 26.4x and 32.8x salinities. incubations conducted at 20.0x and 34.3x salinity, and high at 26.4x and 32.8x salinities. jC constant regime. Embryonic survival was zero in incubations conducted at 20.0x and 34.3x salinity, and high at 26.4x and 32.8x salinities.x and 34.3x salinity, and high at 26.4x and 32.8x salinities.