Relative Egg Weight Research Articles

Adaptation and Performance Evaluation of Layer (Bovan Brown) Chicken Breed in Peri-Urban Areas of Agro-Pastoralist, South Omo Zone, Ethiopia

An experiment targeted the adaptation and performance evaluation of the Bovan Brown chicken breed in peri-urban areas of Agro-pastoralist was conducted in the Malle district. One kebele and 25 households were selected purposively. Training was provided and 21 pullet chickens were distributed to each household. Vaccination was given for the common poultry diseases. The commercial feed was used for the first two months, and then home-prepared feed in addition to kitchen refusal, garden forages, insects, and worms. Mortality was the collective effect of disease, stress, predators, and injury. The average body weight of the breed was 1.5 Kg with an average age of sexual maturity of 6 months. On average the breed laid 237 eggs per hen per year with a relative egg weight of 48, 51, 53, and 57 g at 5%, 10%, 50%, and 95% lay periods, respectively. The breed was preferred due to its survival, egg production, feed conversion ability, and fast age of sexual maturity with some constraints such as feed shortage, absence of the breed, veterinary drugs, and vaccines in the district. The “Bovan Brown” breed was adapted, performed well, and was preferred by the users with the limitation of chicken feed and the awareness gap of keepers. Therefore, the chicken keepers should be trained for the preparation of the layers feed, especially, protein sources, and the distribution of the breed should be limited to urban, per-urban, and trained keepers with access to the road to buy inputs and sale outputs.

Effect of guinea fowl egg storage duration on embryonic and physiological parameters, and keet juvenile growth

This study investigated the effects of guinea fowl hatching eggs storage time on embryo parameters and post-hatch juvenile growth. A total 1,800 eggs of guinea fowl were used. They were numbered, weighed, and divided into four groups of 450 eggs each according to storage time of 3, 7, 11, and 15 D before storage at a temperature of 18°C. Then, they were incubated at 37.7°C and 55% relative humidity for 28 D in a forced-draft incubator. Egg weight loss, albumen pH and weight, embryo weight, hatching events, and keet growth up to 7 D post-hatch were recorded. In addition, thyroid hormone and corticosterone levels were determined. The results indicate that during storage, relative egg weight loss increased with storage duration. However, albumen pH increased with storage time up to 11 D of storage and remained unchanged between 11 and 15 D. In addition, from 19 to 22 D of incubation, albumen weight was higher for eggs stored for 15 D compared to that of eggs stored for 3 to 11 D. But, from 16 D of incubation, embryos from eggs stored for 3 D grew faster than those from eggs stored for 7 to 15 D. Incubation durations up to internal pipping (IP), external pipping (EP), and hatching events increased with egg storage duration. At IP, corticosterone and triiodothyronine (T3) concentrations of eggs stored for 15 D had the lowest (P < 0.05) compared to those of eggs stored for 3 to 11 D. Moreover, the levels of thyroxine (T4) decreased with storage duration (P < 0.05). At hatch, corticosterone levels increased while T4 levels decreased with storage duration (P < 0.05). Also, hatchability decreased with egg storage duration. In addition, 7-day-old keets from eggs stored for 3 and 7 D had comparable weight and were heavier than those from eggs stored for 11 D. It was concluded that storage of guinea fowl hatching eggs more than 7 D negatively affects egg quality and subsequently depresses embryo and post-hatch growth.

Impacts of various storage periods on egg quality, hatchability, post-hatching performance, and economic benefit analysis of two breeds of quail.

The effect of storage period on hatching and post-hatching performance of two quail breeds (brown Japanese quail (BJQ) and French white quail (FWQ)) was investigated using 940 eggs from each breed. Eggs were divided into four equal groups (235 eggs each), in each group. A total number of 210 eggs were used for incubation (with three replicates, 70 eggs each) and additional 25 eggs served as samples for egg quality parameters, each group was kept for special storage period. The first group was incubated on the same day of collection (zero day storage). Whereas the second, third, and fourth groups were stored for 4, 7, and 10 d, respectively. Increasing the storage period more than 4 d significantly decreased the relative albumen weight, yolk index, total hatchability, and fertile eggs but significantly increased the relative yolk/albumen ratio, absolute and relative egg weight loss. Moreover, FWQ eggs exhibited higher (P < 0.05) hatchability compared to BJQ eggs after 10 d of storage and yielded heavier chicks (P < 0.05) after all storage periods. The economic analysis indicated that the storage costs for FWQ eggs were significantly greater than those of BJQ at a 0 d of storage (2.42vs. 4.81 US cent (¢); P < 0.05). Furthermore, the total costs for BJQ eggs were significantly lower than the total costs for FWQ eggs (3.0vs. 7.0 ¢; P < 0.05). With respect to profitability, the total return represented by selling the chicks was calculated at 5.43 ¢ for BJQ and 9.01 ¢ for FWQ. The net return estimated for FWQ was significantly greater than that of BJQ (3.0vs. 2.0 ¢; P < 0.05). However, the hatchability loss for FWQ was significantly greater than that of BJQ over different storage periods.

Reproductive performance of asian catfish ( Hemibagrus wyckii Bleeker, 1858), a candidate species for aquaculture.

Background:Hemibagrus wyckii Bagridae is one of the important economic fish species that lives in the rivers and reservoir in Riau Province, Indonesia. The present study aimed to determine the reproductive performance of H.wyckii under culture conditions. Methods: A total of 10 female and 10 male fish were selected, and weight, length, characteristics of egg and sperm, and hatchery performance were measured. Eggs were fertilized using the dry method. Egg weight and egg diameters were measured for 50 eggs per female. Egg size (50 eggs for each fish) was measured using Labo microscope model L-711 using software camera 3. Then, saline solution was added over the eggs, followed by the addition of pooled sperm from 10 males. Results: Average relative fecundity, egg weight and egg diameter were 2060±512 eggs/kg fish, 29.86±1.21 mg and 2.67±0.26 mm, respectively. The fertilization rate and hatching rate were 60.91±4.68% and 42.91±2.92% respectively. Sperm characteristics such as volume per fish (mL), pH, concentration (per mL), motility (%) and duration of motility (second) were 0.82±0.20, 7.15±0.12, 3.68±0.15, 72.77±1.46 and 47.5±4.84, respectively. Conclusion: The study results and scientific observations regarding reproductive performance suggest that H. wyckii can be considered a new candidate species for aquaculture.

Reproductive performance of asian catfish ( Hemibagrus wyckii Bleeker, 1858), a candidate species for aquaculture

Background: Hemibagrus wyckii Bagridae is one of the important economic fish species that lives in the rivers and reservoir in Riau Province, Indonesia. The present study aimed to determine the reproductive performance of H.wyckii under culture conditions. Method s: A total of 10 female and 10 male fish were selected, and weight, length, characteristics of egg and sperm, and hatchery performance were measured. Eggs were fertilized using the dry method. Egg weight and egg diameters were measured for 50 eggs per female. Egg size (50 eggs for each fish) was measured using Labo microscope model L-711 using software camera 3. Then, saline solution was added over the eggs, followed by the addition of pooled sperm from 10 males. Results: Average relative fecundity, egg weight and egg diameter were 2060±512 eggs/kg fish, 29.86±1.21 mg and 2.67±0.26 mm, respectively. The fertilization rate and hatching rate were 60.91±4.68% and 42.91±2.92% respectively. Sperm characteristics such as volume per fish (mL), pH, concentration (per mL), motility (%) and duration of motility (second) were 0.82±0.20, 7.15±0.12, 3.68±0.15, 72.77±1.46 and 47.5±4.84, respectively. Conclusion: The study results and scientific observations regarding reproductive performance suggest that H. wyckii can be considered a new candidate species for aquaculture.

Reproductive performance of asian catfish (Hemibagrus wyckii Bagridae), a candidate species for aquaculture

Background: Hemibagrus wyckii Bagridae is one of the most important economic fish species that lives in the rivers and reservoir in Riau Province, Indonesia. The present study aimed to determine the reproductive performance of H.wyckii under culture conditions. Methods: A total of 10 female and 10 male fish were selected, and weight, length, characteristics of egg and sperm, and hatchery performance were measured. Eggs were fertilized using the dry method. Egg weight and egg diameters were measured for 50 eggs per female. Egg size (50 eggs for each fish) was measured using an Olympus microscope (CX40). Then, saline solution was added over the eggs, followed by the addition of pooled sperm from 10 males. Results: Average relative fecundity, egg weight and egg diameter were 2060±512 eggs/kg fish, 29.86±1.21 mg and 2.67±0.26 mm, respectively. The fertilization rate and hatching rate were 60.91±4.68% and 42.91±2.92% respectively. Sperm characteristics such as volume per fish (mL), pH, concentration (per mL), motility (%) and duration of motility (second) were 0.82±0.20, 7.15±0.12, 3.68±0.15, 72.77±1.46 and 47.5±4.84, respectively. Conclusion: The study results and scientific observations regarding reproductive performance suggest that H. wyckii can be considered a new candidate species for aquaculture.

Egg laying characteristics, egg weight, embryo development, hatching weight and post-hatch growth in relation to oviposition time of broiler breeders

Two experiments were conducted to determine egg laying characteristics and the effects of oviposition time on egg weight, embryo development and post-hatch growth in broiler breeders. In experiment 1, eggs collected for 3 consecutive days on hourly basis between 06:30 and 17:30h were categorized to early, middle and late oviposition times in the clutch. In experiment 2, eggs were incubated to study embryo development, remaining albumen, liver weight, heart weight and the tibia length of embryos at 12, 14, 16 and 18 days of incubation as well as the body weight of hatchlings and chickens at 7, 21 and 42 days of age in relation to oviposition time. About 76% of nest eggs were laid from 06:30 to 11:30h. A similar pattern was observed in floor eggs. Egg weight decreased (P<0.01) with advanced position in the clutch. Generally, oviposition time had no effect on embryo growth parameters. At hatch, body weight of chicks derived from eggs of late oviposition times was less (P<0.01) than that of chicks from eggs produced earlier in the clutch. From 3-week-old onwards, chickens of early oviposition time sustained heavier (P<0.05) weight than chickens of middle oviposition time whereas chickens of late oviposition time obtained a middle weight. Differences in egg weights, body weight at hatch and post-hatch growth due to time of oviposition suggest that oviposition time together with incubation conditions should be considered for obtaining greater uniformity and growth of chickens.

Production aspects of broiler breeders submitted to different drinker types

The objective of this study was of evaluate the influence of different drinker types on the egg production, water intake, mortality, poultry litter relative humidity, egg weight, eggshell percentage, and egg specific gravity of broiler breeders. The experiment was carried out in a commercial farm with 37- to 44-wk-old broiler breeders. A randomized block experimental design, consisting of two treatments (bell or nipple drinkers) with four replicates of 4.000 females each, was applied. Data were submitted to analysis of variance, and means were compared by the test of Student-Newman-Keuls at 5% significance level. Birds submitted to nipple drinkers presented lower water intake (p 0.05) of drinker type on egg production or mortality. Poultry litter relative humidity was lower (p<0.05) under the nipple-drinker system. Birds drinking from bell drinkers produced heavier eggs (p<0.05) between weeks 39 and 40. Hens drinking from bell drinkers laid eggs with higher specific gravity and eggshell percentage. It was concluded that nipple drinkers can be used for broiler breeders during lay.

Feeding Ration, Genetics, and Reproductive Traits in Female Coho Salmon: Is Bigger Better?

We assessed the effects of different feeding regimes on reproductive traits in coho salmon, Oncorhynchus kisutch. Ration treatments subjected fish to different energy levels during oocyte proliferation (Year 1) and oocyte maturation (Year 2). Fish from 10 full-sibling families were fed at either the recommended feeding rate or double the recommended ration during the first year. At the beginning of the second year, each ration group was split again into recommended and double ration tanks for a total of four dietary treatments. At the end of the second year, 365 females from the four treatment groups were spawned and body weight, egg weight, and egg number were measured. Overall, the fish fed the double ration during both years grew the fastest (50.1% larger than controls), had the highest egg number (46.3% larger), and had the largest eggs (9.6% larger), although similar increases were observed feeding at the double ration level during the second year alone. Ration modification produced significant changes in some reproductive traits, especially egg number, while family effects had a greater influence on relative fecundity (eggs/g female body weight) and egg weight. In fact, family effects were significant for all of the traits. Results indicate that reproductive traits can be manipulated through changes in ration and/or via genetic selection, either directly or indirectly.

Effect of oxygen supplementation in the hatcher at high altitude on the incubation results of broiler eggs laid at low altitude

1. The object of this research was to investigate the effects of high altitude with supplementary oxygen during the last stage of incubation of broiler eggs laid at low altitude and incubated at low and high altitude. We analysed thyroid hormones and haematological variables. 2. The treatment groups were: low altitude (LA), high altitude with oxygen supplementation in the hatcher (HA-OX) and high altitude non-oxygen-supplemented (HA-NOX). 3. High altitude affected relative egg weight loss and early embryonic mortality. The hatchability of fertile eggs was lower at high than at low altitude. 4. Oxygen supplementation into the hatcher cabinet during the last stage of incubation decreased late embryonic mortality ratio (LEM1) and improved survival rates of embryos incubated at high altitude. 5. Eggs incubated at low altitude had a higher hatched chick weight and relative chick weight than those incubated at high altitude. Hatched chick weight and relative chick weight did not change with oxygen supplementation at high altitude. 6. High altitude caused an increase in plasma T3 and T4 concentrations as well as in the ratio of T3:T4 in embryos. High altitude newly hatched chicks showed a higher T3:T4 ratio than low altitude chicks; this ratio decreased with oxygen supplementation at high altitude. Altitude and oxygen supplementation did not affect the mean plasma T4. 7. Newly-hatched chicks incubated at high altitude showed a higher plasma haematocrit (PCV) than the newly-hatched chicks from eggs incubated at low altitude. High altitude without supplementation increased haemoglobin (Hb), while oxygen supplementation returned the value to low altitude values.

Comparison of Cobb and Ross strains in embryo physiology and chick juvenile growth

Broiler performance is known to be related to embryonic developmental parameters. However, strain or genotype differences with regard to embryo physiological parameters and juvenile growth have received little attention. A total of 1,200 hatching eggs produced by Cobb and Ross broiler breeders of the same age were studied. At setting for incubation and between 66 and 130 h of incubation, egg resonant frequency (RF) was measured as an indicator of embryonic development. Also, eggs were weighed before setting and at d 18. From d 10 to 18 of incubation, remaining albumen was weighed. During the last days of incubation, hatching events such as internal pipping (IP), external pipping, and hatch were monitored every 2 h. Hatched chicks were recorded and weighed. At IP stage, gas partial pressures in the egg air chamber were measured. Hatched chicks were reared for 7 d and weighed. Results indicate that RF of Ross eggs were lower than those of Cobb eggs (P < 0.01) and starting time point of RF decrease occurred earlier in Cobb eggs than in Ross eggs. Relative egg weight loss up to 18 d of incubation was lower in Cobb than in Ross (P < 0.05). At IP, partial pressure of CO(2) was higher in Cobb than in Ross (P < 0.05) with shorter incubation duration in Cobb. Between 6 and 60 h posthatch, heat production was higher in Cobb than in Ross (P < 0.05). At 7 d posthatch, Cobb chicks were heavier than Ross chicks (P < 0.05). It is concluded that Cobb and Ross embryos-chicks have different growth trajectories leading in different patterns of growth resulting from differences in physiological parameters.

Comparison of a modern broiler and layer strain during embryonic development and the hatching process

1. This research focused on the embryonic development of broiler and layer embryos. 2. Egg, embryo and yolk weights were measured and partial pressure of gases in the air cell and blood were analysed at several embryonic ages. The static stiffness of the eggshell was measured before the start of incubation and at embryonic day (ED) 18 to register the change in shell strength. Times of internal pipping (IP), external pipping (EP) and hatch were recorded. Plasma corticosterone, triiodothyronine and thyroxine concentrations were determined. 3. Relative egg weight loss was higher in layer eggs. Before ED16, layer embryos showed a slower development which was reflected in lower (relative) embryo weight, lower air cell and blood pCO2 and higher air cell O2. From ED16 onwards, relative growth rate accelerated in the layer strain; as a consequence the difference in relative yolk-free chick weight at hatch had disappeared between strains. 4. Differences in physiological events necessary for hatching (thyroid hormones, corticosterone, air cell pCO2) are most probably responsible for the observed differences in timing of pipping and hatching events between layer and broilers.

Oviposition pattern, egg weight, fertility, and hatchability of young and old broiler breeders

Two experiments were conducted to investigate egg weight, fertility, hatchability, and embryonic mortality in relation to time of oviposition of young and old broiler breeder flocks. In experiment 1, eggs were collected from 2 flocks (34 and 59 wk) for 2 d at hourly intervals between 0700 and 1900 h. Most eggs were laid between 0700 and 1300 h, but eggs were laid later in the day by the old flock. Weights of early laid (C1) eggs were significantly greater than middle laid (Cs) and the late laid (Ct) eggs in the young flock, whereas late laid eggs (Ct) were significantly smaller than early laid (C1) and middle laid (Cs) eggs in the old flock. In experiment 2, eggs from experiment 1 were categorized as early laid first-in-sequence (C1) eggs (0700 to 0800 h), the mid-sequence (Cs) eggs (0900 to 1200 h), and the late laid terminal-in-sequence (Ct) eggs (1300 to 1700 h). These eggs were incubated to determine fertility, hatchability, and stage of embryonic mortality relative to oviposition time and flock age. Fertility declined with flock age, but there were no differences due to time of oviposition. There were no differences in hatchability of fertile eggs or embryonic mortality relative to time of oviposition (sequence position) or flock age. These results suggested that although there were differences in egg weight among eggs at different times of the day (different sequence positions), there were no differences in fertility, fertile hatchability, or embryonic mortality in naturally mated broiler breeders.

Relationships among prehatch and posthatch physiological parameters in early nutrient restricted broilers hatched from eggs laid by young breeder hens

The objective of this study was to establish relationships among various physiological parameters in early (through 72 h posthatch) nutrient restricted broiler chicks from young breeder hens. Despite a 19% decrease in mean BW between 0 and 72 h posthatch, there were no chick mortalities. Liver glycogen peaked at 24 h, and peaks in rectal temperature, plasma glucose, and plasma refractive index occurred at 48 h. By 24 h, negative correlations were noted between BW and relative liver weight and between liver glycogen and both refractive index and rectal temperature. By 24 h, positive correlations were noted between relative liver weight and liver glycogen, BW and plasma glucose, rectal temperature and plasma glucose, and rectal temperature and body fat loss score. Mean daily relative egg weight loss between 0 and 19 d of incubation (RIEWL) was positively correlated with rectal temperature at 0 h but was negatively correlated with rectal temperature at 24 h and liver glycogen at 24 and 48 h. Furthermore, mean relative hatching chick weight (RHCW) had significantly positive correlations with plasma glucose at 6 h and rectal temperature at 48 and 72 h. Broilers having a greater RHCW after hatching from eggs with a lower RIEWL may maintain higher metabolic rates between 24 and 72 h posthatch despite nutrient deprivation. However, broiler chicks from eggs exhibiting a higher than optimal RIEWL may have greater dependence on gluconeogenesis, thus requiring stricter management during initial brooding.

Is Monogamy in the Polynesian Megapode (Megapodius pritchardii) Related to Its High Relative Egg-Weight?

Is Monogamy in the Polynesian Megapode (Megapodius pritchardii) Related to Its High Relative Egg-Weight?

Is Monogamy in the Polynesian Megapode (Megapodius Pritchardii) Related to its High Relative Egg-Weight?

AbstractParental care is regarded as one of the most influential forces acting on the evolution of mating systems. Polynesian Megapodes (Megapodius pritchardii) are burrow nesters and rely on geothermal heat for incubation. Because they provide no parental care, either before or after hatching, they can provide insights into selective forces that have shaped mating systems in the absence of parental care. Our study of their mating system—the first such study of any burrow-nesting megapode—suggests social monogamy. The partners of 10 marked pairs stayed together in the same territory for ≤12 months and were seen with their partner significantly more often than on their own. In 64% of all observations, pair partners foraged &lt;5 m apart, and females fed on food items uncovered by the male. Duets also indicated long-lasting pair bonds. We propose that monogamy in this species is related to the fact that females lay only one large egg at a time (which weighs, on average, 24% of her body weight), in intervals of several days or weeks. Producing eggs year-round, females require a high intake of protein-rich food. They seem to benefit, within the pair bond, from the male-defended feeding territory and from the invertebrates the male uncovers while feeding close by. While being guarded by the male, females can spend more time searching for food and are protected from forced copulations by other males. The monogamous pair bond seems to benefit the male by enhancing his chances of fertilizing his partner's eggs; with an unpredictable laying interval and year-round egg production, males cannot predict when their partner will be fertile and thus benefit from staying with her year-round.

Life history adaptations and stress tolerance of four domestic species of Drosophila

AbstractLife history traits and stress tolerance were studied in four domestic species of Drosophila–D. melanogaster, D. simulans, D. auraria and D. immigrans– to understand how they adapt to their environments. In all species, larval weight approximately doubled in 1 day. The relative egg weight (egg weight : pupal weight) was smaller and the larval period was longer in D. immigrans than in the other three species. The pupal period was the longest in D. auraria. However, the adaptive significance of these differences in larval and pupal periods was not clear. The pupal case was generally thicker in the larger species, probably to support the larger pupal body. The start of oviposition was earliest and reproductive effort was greatest in female D. simulans, followed by female D. melanogaster. In contrast, starvation tolerance and the increase in bodyweight after eclosion was greater in D. immigrans and D. auraria than in the other two species. Pupal desiccation tolerance was greatest in D. melanogaster and lowest in D. auraria, and the less tolerant species seemed to select more humid sites for pupation. Adult tolerance to desiccation was greatest in D. melanogaster and lowest in D. simulans. In contrast, adult cold tolerance was greater in D. auraria and adult heat tolerance was lower in D. immigrans than in the other species. These differences in life history traits and stress tolerance represent the Drosophila species differential adaptations, and are assumed to allow coexistence of the species.

Successful gonadal development and maturation of tench (Tinca tinca L.) in small concrete ponds

Summary The experiments were performed in a tench farm from autumn until the spawning season (June–July). Tench broodstocks from natural habitats were maintained in 25 × 6 × 1 m concrete ponds and fed on commercial trout pellets. Females and males were separated and maintained under natural photoperiod and temperature conditions at densities around 2 kg m−2. Water flow throughout was supplied at the rate of 15 L s−1. When females showed external signs of advanced gonadal development, induction of spawning was made by luteinizing hormone releasing factor (LH-RH) synthetic analogue administration at three different periods of the reproductive season (June–July). A single intramuscular injection (20 μg kg−1 body weight) was administered to 110 mature females selected from a total of 150. The females were stripped 42 h (22°C) after hormone administration. The mean rate of stripped females to the number injected was 77%. Mean relative egg weight in relation to the weight of the stripped females was 5.61%. More than 90% of the males provided semen without hormonal induction. Differences in egg production and external egg quality were observed at different times of the spawning period. It was proven that tench maintained in small concrete tanks and fed on artificial diets were able to reach gonadal maturation.

Relationship Between Broiler Breeder's Age and Egg Weight Loss and Embryonic Mortality During Incubation in Large-Scale Conditions

The age of broiler breeders is an important parameter to be taken into account by the hatchery manager. Eggs produced by young or old breeders do not hatch as well as the eggs from the breeders of 40 to 42 wks of age. Field reports indicate that there are quadratic relationships between age of breeders and absolute egg weight loss during incubation, age of breeders and hatchability, and age of breeders and embryonic mortality. There is a trend of optimum relative egg weight loss on Day 18 of incubation for the highest hatchability. These results indicate that the eggs that incubate best are produced by the hens of 40 to 42 wk of age. It is suggested that the egg characteristics and the age of breeders have to be taken into account during incubation in order to design optimal incubation conditions and to improve hatchability. However, because the relative egg weight loss is not linked to the age of breeders, regulation of relative humidity during incubation to achieve optimum weight loss may take into account only the eggs characteristics.

Holding temperature during the breeding season influences final maturation and egg quality in common wolffish

Mature common wolffish, Anarhichas lupus L., previously held at 8°C for several months, were exposed to 4, 8 or 12°C throughout the breeding season (November‐January). Regardless of temperature, some females ovulated in early‐November, but thereafter ovulation was delayed in the 8 and 12°C groups compared with the 4°C group. Temperature experienced by the adult fish also affected egg development and survival even though eggs were incubated at a common temperature of 6°C. The percentages of normally cleaved eggs (at the 32‐cell stage) and egg survival to the eyed stage were significantly lower in the 12°C group (8%) than in the 4°C (73%) and 8°C (48%) groups. The differences in egg survival were also significant between the 4 and 8°C groups. Egg survival was also influenced by the length of time the broodfish had been exposed to the different temperatures: at 4 and 12°C there were significant positive and negative relationships, respectively, between egg survival and the number of days for which the female had been exposed to the given temperature prior to ovulation. Temperature experienced by the female did not affect egg size, relative egg weight, fertilization rate, relative fecundity or the number of ovulating individuals. The results indicate that both the timing of ovulation and egg quality of common wolffish are affected by the temperature experienced during the breeding season.