Geology topics

L.T. Brooke

Publications and source records attributed to L.T. Brooke.

4 recordsLinked to original sources

USGS1980

Development and survival of embryos of lake herring at different constant oxygen concentrations and temperatures

Eggs of lake herring (Coregonus artedii) were incubated in a continuous-flow system at four constant water temperatures (2-8°C) and five dissolved oxygen (DO) concentrations (1-12 mg/L). In comparison with incubation time at 12 mg/L DO, time to median hatch was significantly longer (P<0.05) at 2 mg/L at 6°C (no hatch at 1 mg/L), at 3 mg/L or less at 4°C, and at 4 mg/L or less at 2°C. The time between hatching of the first and last eggs varied inversely with temperature. Mean total lengths of newly hatched fry were significantly shortened (P < 0.05) at 1 and 2 mg/L DO. At 6 and 8°C, percent survival through hatching was greater than at 2 and 4°C at DO of 4 mg/L or more, but fell to zero at 1 mg/L. The percentage of normal fry produced decreased noticeably below 4 mg/L DO. The optimum temperature for highest percentage survival of normal fry decreased directly with the level of dissolved oxygen. The temperatures at which the highest percentages of normal fry hatched from eggs incubated at DO concentrations of 4 or 8, 2, and 1 mg/L, were 6, 4, and 2°C, respectively-indicating a decreasing DO demand by embryos incubated at the lower temperatures. Our findings supported a previously published hypothesis that DO concentrations below 4 mg/L can be adverse to survival and development of coregonid embryos in nature.

Progressive Fish-Culturist↗

USGS1977

Verification of a model for predicting the effect of inconstant temperature on embryonic development of lake whitefish (Coregonus clupeaformis)

Eggs stripped from lake whitefish (Coregonus clupeaformis) spawning in Lake Michigan were incubated in the laboratory at temperatures similar to those on whitefish spawning grounds in Lake Michigan during December-April. Observed times from fertilization to attainment of each of 21 developmental stages were used to test a model that predicts the rate of development at daily fluctuating temperatures; the model relates rate of development for any given stage j, expressed as the reciprocal of time (Rj), to temperature (T). The generalized equation for a developmental stage is Rj = abTcT??. Observed times agreed well (5.5% mean difference for all stages) with times predicted by the model; the observed time of 135 days from fertilization to hatching (stage 21) was only 5 days (3.7%) less than the predicted time of 140 days. The model was further verified by applying it to unpublished data supplied by the Ontario Ministry of Natural Resources, for eggs from Lake Huron whitefish incubated in the laboratory in untempered Lake Huron water. The model was used to predict the effects of small temperature increases (caused by a hypothetical waste-heat discharge) on the rate of development and time of hatching of lake whitefish eggs. According to this simulation, continuous addition of waste heat sufficient to raise the temperature 1, 2, or 3 C above ambient on the spawning grounds during December-April would advance the time of hatching 8, 16, or 21 days, respectively. Possible effects of this advancement on the reproductive success of whitefish are discussed.

Technical Paper↗

USGS1973

Effects of temperature on embryonic development of lake herring ( Coregonus artedii )

Embryonic development of lake herring ( Coregonus artedii ) was observed in the laboratory at 13 constant temperatures from 0.0 to 12.1 C and in Pickerel Lake (Washtenaw County, Michigan) at natural temperature regimes. Rate of development during incubation was based on progression of the embryos through 20 identifiable stages. An equation was derived to predict development stage at constant temperatures, on the general assumption that development stage (DS) is a function of time (days, D) and temperature (T). The equation should also be useful in interpreting estimates from future regressions that include other environmental variables that affect egg development. A second regression model, derived primarily for fluctuating temperatures, related development rate for stage j (DR j ), expressed as the reciprocal of time, to temperature (x). The generalized equation for a development stage is: DR j = ab x c x 2 d x 3 . In general, time required for embryos to reach each stage of development in Pickerel Lake agreed closely with the time predicted from this equation, derived from our laboratory observations. Hatching time was predicted within 1 day in 1969 and within 2 days in 1970. We used the equations derived with the second model to predict the effect of the superimposition of temperature increases of 1 and 2 C on the measured temperatures in Pickerel Lake. Conceivably, hatching dates could be affected sufficiently to jeopardize the first feeding of lake herring through loss of harmony between hatching date and seasonal food availability.

Michigan↗

USGS1970

Survival and development of lake herring (Coregonus artedii) eggs at various incubation temperatures

Lake herring eggs stripped and fertilized from a local stock were incubated in a constant-flow incubator at constant temperatures ranging from 0 to 12.1° C. Rate of development, percentage survival, percentage of abnormal and normal hatching, and length of fry at hatching were determined. The average incubation time from fertilization to 50% hatch varied from 37 days at 9.9-10.3° C to 236 days at 0.5° C. The optimum temperature range for normal development was approximately 2 to 8° C. Eggs incubated at 0 and 12.1° C developed but did not hatch. Mortality was high among eggs incubated at 0.5 and 10.0° C. Most of the mortalities came during the early stages of development. The incidence of abnormalities was highest among fry hatched at 10° C, and was high in the one incubation series in which the eggs were rolled because of a high flow rate. Total length of fry at hatching decreased with increased incubation temperature. A comparison of survival and development between lake herring and whitefish ( Coregonus clupeaformis ) at various constant incubation temperatures suggests that lake herring have a higher optimum temperature (5.6 °C) than whitefish (0.5 °C) for successful development.

Book chapter↗