Hatch Date Research Articles

Hatch timing of largemouth bass: implications for recruitment at the Northern edge of their native range

Climate-related shifts in hatch timing could mean that age-0 largemouth bass Micropterus salmoides in north temperate lakes reach larger sizes and experience higher survival, which may contribute to increased prevalence of this species in many lakes. However, information on age-0 largemouth bass life history is lacking for these lakes. We estimated hatch dates, daily growth rates (DGR), and length-based probability of piscivory of age-0 largemouth bass in Wisconsin lakes to: (1) provide baseline data on early life history; (2) compare hatch timing between years with different spring temperature regimes, and (3) project how shifts in hatch timing might influence total length (TL) distributions of age-0 bass if mean DGR remained constant. Most age-0 largemouth bass (>90%) collected from ten Wisconsin lakes (N = 746) hatched between 23 May and 24 June during 2012 and 2013 and did not switch to piscivory during their first summer. Prevalence of positive correlations (16 of 24 lake-year pairings) between TL in and age indicates hatch timing may influence TLs attained by age-0 largemouth bass in August in some lake-years. Mean daily water temperatures in May 2012 were 3.1 °C warmer than in May 2013 for the five of the six lakes where hatch dates were estimated in both years. On average, earliest and median hatch dates for age-0 largemouth bass in these six lakes were 10–11 d earlier in 2012 than in 2013 and hatch duration was approximately 8 d longer in 2012. Despite differences in hatch timing, mean DGR was relatively consistent (range = 0.61–0.74 mm/d) between lakes and years. Simple simulations suggest that earlier hatch dates could result in more age-0 largemouth bass reaching TLs associated with piscivory and overwinter survival by the end of their first summer if growth rates did not change, which could translate to higher recruitment.

Age, not growth, explains larger body size of Pacific cod larvae during recent marine heatwaves

Marine heatwaves (MHWs) are often associated with physiological changes throughout biological communities but can also result in biomass declines that correspond with shifts in phenology. We examined the response of larval Pacific cod (Gadus macrocephalus) to MHWs in the Gulf of Alaska across seven years to evaluate the effects of MHWs on hatch phenology, size-at-age, and daily growth and identify potential regulatory mechanisms. Hatch dates were, on average, 19 days earlier since the onset of MHWs, shifting a mean of 15 days earlier per 1 ℃ increase. Size-at-capture was larger during & between MHWs but, contrary to expectations, larvae grew slower and were smaller in size-at-age. The larger size during & between MHWs can be entirely explained by older ages due to earlier hatching. Daily growth variation was well-explained by an interaction among age, temperature, and hatch date. Under cool conditions, early growth was fastest for the latest hatchers. However, this variation converged at warmer temperatures, due to faster growth of earlier hatchers. Stage-specific growth did not vary with temperature, remaining relatively similar from 4 to 8 ℃. Temperature-related demographic changes were more predictable based on phenological shifts rather than changes in growth, which could affect population productivity after MHWs.

Post-Mucilage Distribution, Daily Growth, Mortality, and Hatch Date Timing of Sand steenbras Lithognathus mormyrus (Linnaeus, 1758) Juveniles in the Sea of Marmara

Post-Mucilage Distribution, Daily Growth, Mortality, and Hatch Date Timing of Sand steenbras Lithognathus mormyrus (Linnaeus, 1758) Juveniles in the Sea of Marmara

Winter moth populations are isolated on co‐occurring tree species with contrasting budburst‐phenology

Abstract Differences between neighbouring tree species in phenology could isolate populations of host plant generalists that depend on matching the phenology of their host. We studied the relationship between the budburst phenology of two co‐occurring tree species with early (hornbeams) and late (oaks) budburst and the egg hatching date of associated winter moths (Operophtera brumata) during two seasons (autumns starting in 2020 and 2021). A previous study in spring 2019 had found no winter moth larvae on the focal oaks, while we found them mainly on oaks with hornbeam neighbours in 2022. Congruently, adult winter moths were rarely encountered during the autumns of 2018 and 2019 and sparsely in 2020 and 2021, and then mainly near hornbeams. The vast majority of winter moths had early hatching eggs when both hornbeams and oaks were present, matching the hornbeams rather than the oaks. Where hornbeam was absent in the neighbourhood, the few winter moths had late hatching eggs. These results suggest that winter moth populations on hornbeam and oak are to some degree isolated from each other despite spatial proximity, so that recolonization of oaks by populations synchronized with budburst of hornbeam is slow. Therefore, trees would benefit from differing from their neighbours in budburst phenology with respect to herbivore damage.

Duckling survival increased with availability of flooded wetland habitat and decreased with salinity concentrations in a brackish marsh

Abstract Waterfowl population recruitment is sensitive to duckling survival. We quantified predator types and survival rates for Anas platyrhynchos (Mallard) and Mareca strepera (Gadwall) ducklings in one of the largest brackish water marshes in western North America (Suisun Marsh, California) using 556 radio-tagged ducklings from 284 broods tracked during the 2016 to 2019 breeding seasons. Overall, 78% of ducklings died and 84% of mortalities occurred < 7 days after hatch. After hatching in upland fields, survival was greater for broods that hatched closer to flooded wetlands; broods had a ≥ 75% chance of surviving the move from the nest to water when nests were located ≤ 140 m from the nearest wetland and ≤ 50% chance of surviving when nests were located ≥ 970 m from the nearest wetland. Predation accounted for 91% of mortalities and was attributed to mammals (27.6%), birds (22.0%), snakes (4.4%), and unknown predators (46.0%). Anas platyrhynchos survival to fledging (54 days) was only 3.2% and 0.9% during 2 drier years and 11.7% and 16.7% during 2 wetter years. Mareca strepera survival to fledging was 9.4% to 11.2% among years. Daily survival rates for ducklings generally increased with the amount of flooded wetlands within 0.5 km (A. platyrhynchos) and 1.0 km (M. strepera) of the nest at hatch. Additionally, survival rates increased with duckling age and body mass at hatch for both species and decreased with hatch date for A. platyrhynchos but not M. strepera, which may be partially due to the earlier onset of A. platyrhynchos nesting. For ducklings that survived the initial move to water, survival rates were negatively correlated with salinity and this effect was more pronounced for younger ducklings. Anas platyrhynchos survival to 7 days post hatch decreased by 9.1% (wetter year) to 31.4% (drier year) when ducklings were in 12 ppt water (99th quantile of cumulative salinity concentrations experienced by ducklings) versus 0.5 ppt water. Mareca strepera survival to 7 days decreased by 7.4% when ducklings were in 12 ppt vs. 0.5 ppt water. Our results suggest that maintaining a network of low salinity wetlands within 1 km of upland nesting sites would likely improve duckling survival rates, especially during the critical 7-day period after hatch.

Sex ratio and sex-specific chick mortality in a species with moderate sexual size dimorphism and female brood desertion

An equal sex ratio at the population level is the usual, evolutionarily stable condition. However, at the individual level, it may be adaptive for parents to manipulate the sex of their offspring, especially in species with sexual size dimorphism (SSD) when the costs and benefits of producing sons and daughters can vary. In this study, we investigated the hatching sex ratio (HSR) and fledging sex ratio (FSR) in the Whiskered Tern (Chlidonias hybrida). Despite the fact that SSD exists in Whiskered Terns already at the chick stage, HSR and FSR did not deviate from parity at the population level. We tested the dependence of HSR, FSR and the survival probability of males and females on the individual hatching date, average egg volume (in a clutch) and the number of nestlings. None of these factors influenced HSR. Survival probability was negatively correlated with the number of hatchlings. The proportion of females among the fledglings was positively correlated with the average egg volume per clutch. To better explore the effect of egg volume on the sex ratio, we tested the relationship between exact egg volume and hatchling sex or hatching success at the individual level; but despite the quite large sample size, our analyses failed to reveal any relationship. The sex ratio was equal among chicks that were found dead in a nest, mostly due to starvation, but more female than male chicks disappeared from nests (mostly due to predation), primarily in the first week of life. This indicates that females may be easier to predate, very likely by frogs hunting small chicks.

Land use change and coastal water darkening drive synchronous dynamics in phytoplankton and fish phenology on centennial timescales

AbstractAt high latitudes, the suitable window for timing reproductive events is particularly narrow, promoting tight synchrony between trophic levels. Climate change may disrupt this synchrony due to diverging responses to temperature between, for example, the early life stages of higher trophic levels and their food resources. Evidence for this is equivocal, and the role of compensatory mechanisms is poorly understood. Here, we show how a combination of ocean warming and coastal water darkening drive long‐term changes in phytoplankton spring bloom timing in Lofoten Norway, and how spawning time of Northeast Arctic cod responds in synchrony. Spring bloom timing was derived from hydrographical observations dating back to 1936, while cod spawning time was estimated from weekly fisheries catch and roe landing data since 1877. Our results suggest that land use change and freshwater run‐off causing coastal water darkening has gradually delayed the spring bloom up to the late 1980s after which ocean warming has caused it to advance. The cod appear to track phytoplankton dynamics by timing gonadal development and spawning to maximize overlap between offspring hatch date and predicted resource availability. This finding emphasises the importance of land–ocean coupling for coastal ecosystem functioning, and the potential for fish to adapt through phenotypic plasticity.

Squid male alternative reproductive tactics are determined by birth date.

Alternative reproductive tactics (ARTs) are discontinuous phenotypes associated with reproduction, observed in males of many species. Typically, large males adopt a tactic of competing with rivals for mating, while small males adopt a tactic of stealing fertilization opportunities from the large males. The 'birth date hypothesis', proposing that the date of birth influences the determination of each male's reproductive tactic, has been tested only in teleost fish to date. Here, the birth date hypothesis was tested in ARTs of Japanese spear squid Heterololigo bleekeri (consort/sneaker) by analysing statolith growth increments. The birth date significantly differed between consorts (early-hatched) and sneakers (late-hatched). However, no differences were detected in growth history up to 100 days from hatching. Most immature males caught during the reproductive season were larger than sneakers, and their hatch date was similar to that of consorts, suggesting that these immature males had already been following a life-history pathway as a consort. These results indicate that ARTs of H. bleekeri are determined based on their hatch date in early life. This study firstly suggests that the birth date hypothesis applies to aquatic invertebrates, suggesting that the mechanism by which birth date determines the individual phenotype is a phenomenon more common than previously believed.

Different currencies for calculating resource phenology result in opposite inferences about trophic mismatches.

Shifts in phenology are among the key responses of organisms to climate change. When rates of phenological change differ between interacting species they may result in phenological asynchrony. Studies have found conflicting patterns concerning the direction and magnitude of changes in synchrony, which have been attributed to biological factors. A hitherto overlooked additional explanation are differences in the currency used to quantify resource phenology, such as abundance and biomass. Studying an insectivorous bird (the sanderling) and its prey, we show that the median date of cumulative arthropod biomass occurred, on average, 6.9 days after the median date of cumulative arthropod abundance. In some years this difference could be as large as 21 days. For 23 years, hatch dates of sanderlings became less synchronized with the median date of arthropod abundance, but more synchronized with the median date of arthropod biomass. The currency-specific trends can be explained by our finding that mean biomass per arthropod specimen increased with date. Using a conceptual simulation, we show that estimated rates of phenological change for abundance and biomass can differ depending on temporal shifts in the size distribution of resources. We conclude that studies of trophic mismatch based on different currencies for resource phenology can be incompatible with each other.

Age and growth of larval Pacific flagfin mojarra (Eucinostomus currani) in coastal Ecuador based on otolith analysis

The flagfin mojarra (Eucinostomus currani) is an important subsistence fishery resource in local Ecuadorian markets; however, very little is known about the early life history and reproductive biology of this species. In 2016 and 2017, E. currani larvae were collected at 3 sandy beaches in the Gulf of Guayaquil, Ecuador, and identified using DNA barcoding. Standard lengths ranged from 4.00–15.78 mm. We also collected otoliths to better understand the early life history of E. currani. Otoliths were used to estimate the age, population growth rate (±SE), hatch dates, and reproductive period. On average, the fish were 16.5 ± 4.5 days old, while the average growth rate was 0.70 ± 0.05 and 0.22 ± 0.16 mm per day in March and May, respectively. In the Gulf of Guayaquil, most hatch dates and the presumed reproductive activity of E. currani occurred during the wet season (December–April) when warmer water prevailed. To our knowledge, this is the first study to estimate the hatch dates and larval growth rate for a species of the family Gerreidae in the Pacific Ocean.

Early growth and environmental conditions control partial migration of an estuarine-dependent fish

Partial migration is a widespread phenomenon in animals, whereby multiple groups follow different migration behaviors (i.e. contingents) within a single population. Fishes exhibit particularly high diversity in their early dispersal behaviors; however, whether these represent conditional partial migration behaviors remains unclear. We combined otolith microstructure and chemistry to assess the influence of early life conditions and environmental drivers on juvenile-stage partial migration of anadromous striped bass Morone saxatilis in the Hudson River (USA) in 2 consecutive years with contrasting hydrologic conditions. Time series clustering on otolith strontium (Sr) and barium (Ba) profiles revealed 4 dominant early migration contingents in both years: freshwater residents, oligohaline migrants, small mesohaline migrants, and large mesohaline migrants. In both years, juvenile partial migration appeared to be a conditional strategy linked to a growth-mediated threshold. The propensity to migrate early was related to slower larval growth, whereas freshwater residency and delayed migration were associated with faster larval growth. Differences in hatch dates may have indirectly affected migration contingents by exposing larvae to varying environmental conditions. In the dry year, dispersal timing to mesohaline habitats coincided with high freshwater flow and tidal currents, but not so in the higher-flow year. Recruitment to coastal nurseries outside the Hudson River occurred primarily during the juvenile phase. Early migration contingents could carry over to population dynamics, whereby diverse estuarine nursery habitats contribute differently to recruitment.

Early-Life Population Parameters and Hatch-Date Analysis of Sharpsnout Seabream (Diplodus puntazzo Walbaum, 1792) Juveniles in the Sea of Marmara, Türkiye

This research aims to determine early-life population parameters and hatch date of sharpsnout seabream (Diplodus puntazzo Walbaum, 1792) juveniles using microstructure analyses of sagittal otoliths collected from the Sea of Marmara, Türkiye. Specimens were collected using an experimental beach seine at 12 stations from November 2021 to March 2022. The mean catch per unit effort (CPUE) was 1.1 individuals per haul, with 44.4% of the total D. puntazzo specimens collected at the Erdek Station. A negative allometric growth was calculated from the length-weight relationship equation (W=0.0178L2.698). The daily age ranged between 39 days-1 and 141 days-1, with a mean of 78.9 ± 2.29 days-1. The daily growth rate and mortality ratio were calculated as 0.213 mm/day and 4.38%, respectively. The hatching mainly occurred in September and October.

Early life-history patterns in Patagonian toothfish Dissostichus eleginoides from the Patagonian Shelf

Many long-lived, deep-sea species of the higher latitudes possess protracted egg and larval phases leading to dispersal across large geographical areas. The timing of ontogenetic life-history shifts is vital for understanding dispersal potential, a key driver of spatial patterns and stock structure of Patagonian toothfish Dissostichus eleginoides on the Patagonian Shelf. The early life-history patterns from hatching until settlement into a demersal habitat remain elusive and largely unexplored. We applied a complementary approach using otolith microstructure and trace element analysis (by laser ablation-inductively coupled plasma mass spectrometry) to infer time-resolved elemental profiles that reflect the early ontogeny of age-0+ toothfish from key nursery areas on the Patagonian Shelf. Results revealed significant ontogenetic shifts across the early life history. Key biological benchmarks were identified, including (1) the hatch date distribution (predicted mean = 3 October ± 8.47 d); (2) a period of natal dispersal (0-50 d post hatch [dph]; 22 November); (3) entry of pelagic larvae onto the Patagonian shelf (50-100 dph; 1 January); (4) settlement into a demersal habitat (100-120 dph; 31 January); and (5) the start of a downslope ontogenetic migration along pathways to the continental slope (>120 dph). The results provide important considerations in terms of the complexity and protracted nature of early life-history stages in Patagonian toothfish as a complex process, informing future research objectives relating to the identification of the stock origin on the Patagonian Shelf.

Different growth patterns reveal the potential origins of two Pacific saury (Cololabis saira) groups in the northwest Pacific Ocean

Identification of stock composition is essential for fish stock assessment and management. Previous studies have suggested that a mixed stock composition of Pacific saury Cololabis saira exists in the northwest Pacific Ocean, but the origins of the stock’s components are poorly understood. We analyze the otolith microstructure of Pacific saury collected in high-seas fishing grounds from June–November, 2016–2019, and estimate hatch date and reconstruct otolith growth trajectory before hyaline zone formation. Results confirm that Pacific saury recruiting to the high-seas fishing ground are mainly from a winter-spawned cohort, secondarily from an autumn-spawned cohort, but also with a small proportion from a spring-spawned cohort. Ages of medium (knob length 240–280 mm) and large (knob length > 280 mm) individuals are mainly 8–12 and 18–21 months, respectively. Two growth patterns are reported for individuals with different otolith growth axes in their early life stages. Each year, unsupervised random forest clustering analysis of otolith daily increment widths reveals two Pacific saury groups. One group, with younger age and a later hatching period, shows a consistently higher growth rate than the other, suggesting that the two groups have different hatch dates and locations. These findings permit more accurate prediction of Pacific saury recruitment, and improve the understanding of short-term stock fluctuations to enable more sustainable management of fisheries.

Temperature Dependence of the Breeding Parametres of the Collared Flycatcher (Passeriformes, Muscicapidae) in the National Park Homilshanski Lisy (NE Ukraine)

The breeding phenology of Collared Flycatchers was studied over an 11-year period (2006‒2011 and 2013‒2017) in oak-maple-lime stands located in the Northern-East of Ukraine (in the National Park Homilshanski Lisy). In most years, egg laying began in the first and second ten-day periods of May. The earliest recorded first-egg date (368 broods) was 23 April, while the latest was 5 May. These dates varied from year to year. The relationship between the first-egg date and the date of daily average temperature transition through + 10 °C suggests that birds bred earlier due to warmer local temperatures. The clutch size was negatively correlated with the date of the average air temperature transition through + 5 °C. The earliest hatching date was 15 May, and the latest was 25 May. Fledging typically began in the first half of June. The breeding season’s length ranged from 30 to 42 days, and the breeding cycle was positively correlated with the transition of the average daily temperature through +5 °C. To determine which factors explained the first egg date and clutch size, Generalized Linear Models (GLMs) were conducted. GLMs suggest a correlation between the first-egg date and the sum of effective temperatures (∑T150), arrival date temperature, migration route temperature, and average temperature of the third decade of April. Clutch size is determined by the sum of effective temperature accumulation (∑130) and migration route temperature. Reproductive success is negatively correlated with the average of 30 daily temperatures until the median date.

Citizen complaints in local media as source of mosquito data: the case of Aedes albifasciatus in an intermediate city of temperate Argentina.

Floodwater mosquitoes provoke nuisance due to their mass emergence. Citizen complaints about outstanding events of mosquitoes in urban areas are usually reflected in local media and could be potentially used as data. Our objective was to build a temperature dependent function to characterize the immature development time of the floodwater mosquito Ae. albifasciatus in Tandil (Argentina), and validate it using citizen complaints in local media and field collected mosquitoes. The development time obtained ranges from 5-47 days at 30-7°C, respectively. During 2000-2021, nine mosquito abundance peaks were identified through local journalistic records. For these events, the estimated hatching date was successfully associated with a previous precipitation, with a maximum difference of two days. The precipitation identified as the trigger for egg hatching ranged from 15 to 121 mm. Then, to associate mosquito news with the target species, female mosquitoes were captured by a battery-powered aspirator in green areas of the city during September 2019-June 2021. Six mosquito abundance peaks were detected in which Ae. albifasciatus accounted for 97.3% of the captures. Among them, journalistic records were able to detect the largest two; i.e. in our study above 15 mosquitoes in a five minute collection. Citizen complaints related to nuisance or vector species could be valuable retrospective data for researchers of different fields.

The Effect of the Storage Period of Hatching Eggs on the Date and Specifications of Hatching and Hatching Chicks for Broilers

This locality included the division of eggs into four Factors by 120 eggs for each treatment as follows: The first treatment T1 120 eggs stored for one day. Second treatment T2 120 eggs stored for four days Third treatment T3 120 eggs stored for seven days The fourth treatment T4 120 eggs stored for the eggs of broiler breeder (Ross 308) were obtained from the mothers’ fields of the Rason Poultry Grandfather Company Ltd. / the project of the mothers of Ari - Qushtaba Erbil, located in Erbil governorate near the area of Qushtaba and the age of (42 and 43) weeks. The hatchable eggs were sorted after isolating large, small, dirty and deformed eggs, and the average weight of the eggs for all Factors was 63.6 The eggs were then transferred to the place designated for storing the eggs belonging to the same producing company and the degree of Storage temperature 15-16 ° C and relative humidity 55-60 ° C. The results indicated that the fourth Factor (T4) stored ten days significantly in the TUNA MEASUREMENTS (The rest of the Factors at a significant level (P≤0.05), while no significant effect was recorded for the rest of the Factors at the level of significance (P≥0.05) in all remaining storage factors on a row, while no significant differences appeared for the length of the chicks between all the coefficients.

Assessing potential spawning locations of Silver Chub in Lake Erie

AbstractObjectiveSilver Chub Macrhybopsis storeriana, a predominately riverine species throughout its native range, exists within Lake Erie as the only known lake population. Its population declined in the 1950s and never fully recovered. Canada has listed Silver Chub in the Great Lakes–St. Lawrence River as endangered and has initiated a recovery plan that recognized the identification of spawning areas as a critical component to inform Silver Chub's recovery potential.MethodsWe investigated potential spawning locations of Silver Chub using capture records, otolith microchemistry, and daily age analysis. Lapillus otolith Sr:Ca ratios from 27 age‐0 Silver Chub were used to identify potential spawning areas. Daily ages estimated from lapilli were used to calculate hatch dates, which then were compared with capture data of adults and river flows to further inform potential spawning areas.ResultThe Detroit River (and its nearshore area) was all but ruled out as a potential spawning location. The Maumee, Portage, and Sandusky rivers or their nearshore areas were all possible spawning locations. Projected hatch dates spanned the end of May through the end of June and occurred across a wide range of flows, although some peaks in hatch dates corresponded to flow peaks, indicating recruitment is potentially enhanced by high flows.ConclusionSilver Chub spawning period and hypothesized spawning rivers or lacustuaries overlap those of invasive Grass Carp Ctenopharyngodon idella, creating a need to jointly consider Grass Carp control efforts with conservation of Silver Chub when assessing management alternatives. Further research on spawning guild and the use of rivers themselves or nearshore areas influenced by rivers as spawning areas are required to maximize potential for conservation and recovery of Silver Chub.

Using banding data to estimate primary feather molt and hatch chronology of white‐winged doves in Texas

AbstractBanding data are commonly used to estimate vital rates for migratory game bird management. We used white‐winged dove (Zenaida asiatica) banding data to estimate molt and hatch chronology in Texas. We used Texas Parks and Wildlife Department's long‐term, state‐wide banding data (71,675 banded individuals) from 1 June to 15 August 2007–2016 to investigate primary feather molt and hatching in white‐winged doves in Texas. We estimated primary feather molt and used individual recapture data to determine reliability of models predicting primary feather molt rates. For hatching, we used primary feather molt scores of captured hatch‐year doves to backdate to an estimated hatch date. Our modeling predicted mean after‐hatch‐year primary feather molt rate of 13.21 ± 0.93 days. We predicted 95% of adult white‐winged doves began molting between 7 April to 8 July and completed molt between 17 August to 17 November. Across all years, white‐winged doves hatched as early as 6 January and as late as 27 July, with 95% of all hatching occurring between 22 March and 18 June and peaking on 4 May. Primary feather molt initiation peaked 16 days after the peak of hatching, suggesting that white‐winged doves delay the onset of primary molt until reproductive activity slows. Secondary data collected during banding operations on migratory game birds may be used to understand additional life processes without the requirement to initiate additional survey efforts.

A protected flow breaks the drought for golden perch (Macquaria ambigua) spawning along an extensive semi‐arid river system

AbstractFreshwater ecosystems are under extreme stress due to anthropogenic influences including changing climate, river regulation and water abstraction. Improving our understanding of the hydrological determinants of key life‐history processes of fish, as well as the spatial scales over which these processes occur, is fundamental to inform effective recovery actions. We monitored the spawning response of native fish to a drought‐breaking long‐distance flow pulse that was protected from extraction by a legal intervention order in Australia's northern Murray–Darling Basin. Sampling sites were distributed across >1600 km of the Barwon–Darling River and three of its major tributaries. Larvae of the pelagophilic golden perch (Macquaria ambigua) were captured at all sites, with the size and age distribution indicative of both mainstem and tributary spawning. A mismatch between estimated hatch dates and river discharge at some locations suggested substantial flow‐assisted dispersal from upstream spawning sites, although this was site‐specific and more prevalent at downstream locations. Early life growth rates were the highest at tributary sites compared with mainstem sites, and within mainstem sites, golden perch grew faster in upper reaches compared with lower reaches. The present study provides insight into the environmental benefit of a post‐drought protected flow event whereby connected lotic habitats promoted fish spawning and dispersal over a large spatial scale. Protection of future flow events should occur to support the conservation of golden perch and other pelagophil species, particularly following future drought periods which are forecast to become more intense and frequent.