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The age, growth, reproduction and resource development status of Ptychidio jordani, as a critically endangered freshwater fish in the Hongshui River, China, was studied in this work. A total of 525 specimens were collected monthly using the cages and gillnets from October 2021 to September 2022 in the Hongshui River. The scale was used for age determination, and the maximum age for both female and male was estimated to be 5 years and 3 years, respectively. Female and male P. jordani showed different growth patterns, which were expressed as Lt = 261.3 (1‐e−0.4885(t−0.1476)) and Lt = 251.2 (1‐e−0.4758(t+0.9643)), respectively. The overall sex ratio was 1:0.47 (female:male). Female attained sex maturity at 2.34 years (192 mm body length). Month variation of the gonad somatic index indicated that the spawning period occurred from April to October. The absolute fecundity was estimated at 9046 ± 3434 eggs per individual, and the relative fecundity was 38.08 ± 15.77 eggs per gram. The exploitation rate of female and male was 0.233 and 0.495, which indicated that P. jordani was not overfishing. This study provided data on the key life‐history traits of P. jordani, which has not been known previously and is essential for conservation strategy and policy development. [ABSTRACT FROM AUTHOR]

Growth rate, longevity, maturity and spawning seasonality were estimated for the endemic Hawaiian hogfish Bodianus albotaeniatus. The sex‐specific von Bertalanffy growth parameters are L∞ = 339 mm fork length (LF) and K = 0.66 year−1 for females and L∞ = 417 mm LF and K = 0.33 year−1 for males. The maximum age is 22 years. Histological gonad analysis and the absence of small and young males indicate a monandric protogynous hermaphrodite. Size and age at maturity for combined sexes are L50 = 238 mm LF and A50 = 1.6 years. [ABSTRACT FROM AUTHOR]

Sea pens (Octocorallia: Pennatulacea) constitute one of the most important structural species in soft bottom benthic communities. Most pennatulacean species are deep-water organisms inhabiting depths from 200–6000 m. Among these deep-sea pens, a representative set of colonies from the northeastern Atlantic Anthoptilum murrayi Kölliker, 1880 was collected thanks to the BIOICE research surveys. In this study, 18 colonies of A. murrayi were used to acquire information on essential biological traits such as age and growth rates. Our results showed that the colonies collected ranged between 6–17 years, with a diametric growth rate between 0.10–0.17 mm year−1 and a linear growth rate between 14.97–15.75 mm year−1. Moreover, the number and diameter of oocytes per polyp (PRF, ERF), and the reproductive effort at the colony level (PRE, ERE) were determined. These values were compared between colonies of different sizes and within each colony. The largest observed diameter was 1179 μm for oocytes and 711.3 μm for spermatocysts. Both approaches (growth and reproduction) were correlated, indicating that a given large A. murrayi colony (∼300 mm) might be ∼17 years old and contain >7000 oocytes, from which possibly about 2000 oocytes (∼27%) would be spawned per year. [ABSTRACT FROM AUTHOR]

Age, growth and maturity of frigate tuna (Auxis thazard) were studied for the first time in Southeast Brazil. A total of 650 fish (265–494 mm Fork Length) were sampled from beach-seine landings between March 2018 and February 2019. Sectioned fin spines from 548 specimens were processed and age was determined by counting and measuring of increments. Growth parameters were fitted to length-at-age data using the von Bertalanffy growth function and were compared to the literature using the growth performance index (Phi). Macro and microscopic characterization of gonads and physiological indexes were used for the analysis of the reproductive cycle. The length distribution did not differ by sex. Assigned ages were between 0+ and 4 years, with annual increments formed during winter. Coefficient of variation between readings was 11%. Growth differed by sex, and the von Bertalanffy growth parameters were L∞ = 471 mm; k = 0.47 year−1; and t0 = –1.46 year−1 for females; L∞ = 498 mm; k = 0.35 year−1; and t0 = –2.01 year−1 for males. Phi was 5.0 for both sexes. Estimated growth rate is among the lowest recorded for the species, possibly related to the method used for age and growth assessment. Gonadosomatic index peaked in December, associated with the upwelling of the South Atlantic Central Waters, at a temperature of approximately 16 °C. Spawning activity in colder waters has never been reported for this species and may be influenced by a richer habitat caused by the intrusion of more nutritive rich waters during spring-summer, which allows larval development. Length-at-first-maturity (L50) was 345.4 mm for females and 329.8 mm for males. [ABSTRACT FROM AUTHOR]

The bigeye notothen, Trematomus tokarevi, is a rare nototheniid fish with a putative circum-Antarctic distribution. Due to its prevalent deep water occurrence, this species is rarely caught and its biology poorly known. In addition, this species has been often misidentified with Trematomus nicolai, a morphologically similar species with a partially overlapping distribution. The odd catch of a few specimens of T. tokarevi in the southern Weddell Sea enabled us to provide for the first time preliminary data on reproductive traits and individual age of this species. Fish sample consisted of five females, collected in the austral summer north east of the Filchner Trough at about 750 m depth. Based on histological analyses of gonads, smaller females were in early developing phase, whilst larger ones were regressing, suggesting a summer spawning season, as reported elsewhere. The analysis of growth rings pattern of sagittal otoliths allowed to estimate the individual age, which ranged between 4 and 10 years. In conclusion, this species exhibits most of the common biological traits described in other trematomids, although with some peculiarities, showing at the same time low fecundity and small egg size at spawning. [ABSTRACT FROM AUTHOR]

Despite their wide distribution around the Antarctic continent, the life strategies of the long-fingered icefish Cryodraco antarcticus have been rarely investigated and are not well understood. The aim of this paper was to provide more insights on the demographic characteristics of the population living off the South Shetland Islands, focusing attention on key biological traits such as age and growth and the reproductive cycle. Individual age and reproductive status were assessed through the microstructural analyses of sagittal otoliths and histological analysis of gonads, respectively. The sex-balanced sampled population consisted of juvenile and adult fishes covering a wide size range. Both sexes had positive allometric growth, although males exhibited smaller maximum size and lower body condition than females. Fish longevity was comparable between sexes, being 16 and 18 years in males and females, respectively. Applying the von Bertalanffy growth model to length-at-age estimates, males consistently reached lower maximum asymptotic size at a faster rate than females. Based on the gametogenic process, the spawning period was inferred to occur from late summer to early autumn. As commonly found in icefishes, females devoted a great investment to reproduction as gonadosomatic index, egg size, and fecundity. A single female (62 cm TL) spawned about 7730 eggs as large as 3–4 mm. Considering also the results of previous studies conducted in other areas, this species is characterized by a long-lasting pelagic juvenile phase and adults share similar life strategies across the range of their spatial distribution, suggesting the possibility of a single panmictic circum-Antarctic population. [ABSTRACT FROM AUTHOR]

Dinolestes lewini (longfin pike) is a common, but little studied, fish species endemic to temperate marine-dominated waters below ~31°S on the east, south and west coasts of the Australian mainland and around Tasmania. Samples of longfin pike collected in Lake Macquarie, a large coastal lagoon in south-eastern Australia, were examined for age, growth and reproductive characteristics. Spawning occurred over an extended period between at least October and March (austral spring to autumn), and although spent individuals occurred in samples, spawning location could not be ascertained. Examination of otolith edge condition provided strong support that opaque and translucent zones were deposited annually and that counts of opaque zones on otoliths can be used to estimate ages. Sex-related differences in mean length at age and projected growth based on the von Bertalanffy growth function were evident. Growth trajectories diverged at ~1.5 years of age, after which females grew faster than males for a longer period, eventually attaining greater observed maximum lengths and ages. Observed longevity was 5+ and 9+ years for males and females, respectively. The data provide an initial knowledge-platform for incorporation in species assessments and for further comparative investigations of variation in biological traits across the species' distribution. The longfin pike (Dinolestes lewini) is a common but little studied marine fish species endemic to southern Australia. This is the first reporting of aspects of the species' reproduction and age based on samples collected in Lake Macquarie (NSW). The species has an extended spawning period between spring and autumn. Females grow faster and attain greater maximum lengths and ages than males with observed longevity being 5 and 9 years for males and females, respectively. Photo by John Turnbull. [ABSTRACT FROM AUTHOR]

The basic biology and ecology of the South African east coast round herring Etrumeus wongratanai was investigated from samples of fish collected between 2013 and 2016. This species is short‐lived and reaches a maximum of 3 years of age, with rapid growth in its first year of life. It reproduces from June to December (austral summer) and condition factor was lowest in May through to August and increased from September, probably reflecting the physiological strain before and during spawning. Fish larvae were the most important food items consumed during summer, whereas eucalanid copepods were the most important prey at other times of the year. Stable‐isotope data suggest that there are gradual changes in the trophic level with increasing fish size, δ15N and δ13C values also differed between seasons. The results obtained here are compared with those of other Etrumeus species, regionally and globally. [ABSTRACT FROM AUTHOR]

This study investigated demographic structure and reproductive characteristics of the Atlantic mackerel Scomber scombrus, in relation to landing trends in the northern-central Adriatic Sea. Results highlighted the occurrence of only small-sized and young-age individuals, and a marked decline from the 1990s to the present in maximum age (from 8 to 3 years) and total length ( LT; from 420 to 360 mm). Fecundity ranged between 40 000 and 190 000 eggs, and was related to female LT. High levels of atresia implied lower values of actual fecundity. Sexual maturity was attained by 72·8% of individuals in their first year of life at 200 mm. The reduction in maximum LT resulted in a marked decline in the population egg production, while the reduction in maximum age implied that females participated in fewer spawning events. [ABSTRACT FROM AUTHOR]

Abstract: Fisheries managers worldwide are increasingly using no-take marine reserves (NTMR) to bolster the sustainability of fisheries. Within the Florida Keys National Marine Sanctuary (FKNMS), the Western Sambo Ecological Reserve (WSER) was created to protect a natural area for spawning and a permanent residence area for marine life by eliminating recreational and commercial harvest of resident species. To evaluate whether WSER is meeting these design criteria, we assessed the age structure and potential egg production of the Caribbean spiny lobster (Panulirus argus) population in WSER and in a nearby, unprotected, fished area. Concentration of the age-pigment neurolipofuscin in eyestalks of P. argus was quantified histologically to determine age. We used Monte Carlo simulations to compare the age structure between the two populations of lobster. Lobsters in WSER were older than those in the fished area. Analyses suggested that more than 90% of the lobsters in the fished area were younger than 1.9 years, whereas half of the lobsters in WSER were older than 1.9 years. Moreover, some lobsters may have been the same age (5–6 years) as was WSER itself at the time of the survey, suggesting that they were long-term residents of WSER. Evident in this age-based study was the retention of female lobsters in WSER, as confirmed by the presence of older females, whereas large and thus likely protected females were uncommon during surveys in which only size and sex data were collected. Also, as expected in an older population, the frequency of female lobsters with evidence of maturity was higher in WSER than in the fished areas of the Florida Keys. This research indicates that WSER is functioning as an NTMR, which has resulted in the development of a multiple-year-class lobster population and increased egg production of female lobsters. [Copyright &y& Elsevier]

Wakefield, C. B., Newman, S. J., Marriott, R. J., Boddington, D. K., and Fairclough, D. V. 2013. Contrasting life history characteristics of the eightbar grouper, Hyporthodus octofasciatus (Pisces: Epinephelidae), over a large latitudinal range reveals spawning omission at higher latitudes. – ICES Journal of Marine Science, 70: 485–497.Demographic data on deep-water groupers are limited despite them being highly exploited throughout the Indo-Pacific. In Western Australia, the continuous distribution of the eightbar grouper, Hyporthodus octofasciatus, spans tropical to temperate waters over ∼3500 km from 12°S–35°S. The maximum age was markedly higher in the northern tropical waters than in southern temperate waters, i.e. 47 vs 20 years. Females attained a significantly larger length-at-age in southern temperate waters. Macroscopic and microscopic examination of gonads and annual trends in mean monthly gonadosomatic indices (GSIs) were used to determine that this monandric protogynous hermaphrodite spawns from late spring to summer (October–February) in northwestern Australia. In the temperate waters of WA, there was no evidence of reproduction and no males were observed south of ∼30°S latitude. The lengths at which 50% of female H. octofasciatus matured and changed sex were estimated from northern tropical populations at 560 mm (6.1 years) and 1022 mm (≥11 years). Although the population connectivity of H. octofasciatus is unknown, the spawning omission in temperate waters suggests recruitment from the northern tropical areas and highlights the importance of preserving spawning stocks in those northern waters. [ABSTRACT FROM PUBLISHER]

The humpback red snapper Lutjanus gibbus (Lutjanidae) is an important species for fisheries in the Kagoshima and Okinawan region of Japan. The present study estimated the age, growth and reproduction of this lutjanid species in the waters around Ishigaki Island, southern part of Okinawa. An opaque zone was formed on the otolith every year, and this formation correlated with their spawning season; these zones were identified as annual rings. Maximum ages of 21 and 24 years were observed for males and females, respectively. The von Bertalanffy growth parameters clarifying the age–fork length relationship were as follows: L∞ = 390.5 mm, K = 0.210 year−1 and t0 = −1.88 year for males, and L∞ = 303.4, K = 0.256 year−1 and t0 = −3.05 year for females. The main spawning season was estimated as between May and October, since greater values of gonadosomatic index for females as well as maturation oocytes and/or postovulatory follicles were observed during those six months. [ABSTRACT FROM AUTHOR]

This study presents an assessment of the establishment success of smallmouth yellowfish, Labeobarbus aeneus (Burchell 1822), in the Great Fish River (GFRI), where they were introduced by the Orange-Fish River interbasin water transfer scheme and in the Glen Melville Reservoir (GMR), where the species was subsequently introduced from the GFRI. Edge Analysis of asteriscii validated an annual deposition rate of one growth increment per year and sampled fish were aged at between 0 and 10 years old. Combined sex length-at-age (Lt) was described by Lt = 650(l-e-0.066(t+4.22)) mm FL for GMR and Lt = 498 (l - e -0.23(t + 0.373) mm FL for GFRI. Natural mortality rate was estimated at 0.56/yr in GFRI and 0.96/yr in GMR. Condition factor was significantly higher in the GFRI than in GMR. In comparison with other populations, the GFRI population had reproductive and growth traits that were similar to those in its natural riverine range. Reproductive assessment showed ripe male and female fish in October to December in the GFRI, while in the GMIL ripe male fish but few ripe female fish were recorded. This was attributed to the lack of spawning cues in the reservoir. As a result, L. aeneus were considered established in the GFRI, but were not established and likely dependent on introductions in the GMR. [ABSTRACT FROM AUTHOR]

Allen MG, Morgan DL, Gill HS. Distribution, zoogeography and biology of the Murchison River hardyhead ( Craterocephalus cuneiceps Whitley, 1944), an atherinid endemic to the Indian Ocean (Pilbara) Drainage Division of Western Australia. Ecology of Freshwater Fish 2005. © Blackwell Munksgaard, 2005 The Murchison River hardyhead ( Craterocephalus cuneiceps) is endemic to the extremely arid Indian Ocean (Pilbara) Drainage Division of Western Australia, where it is found in the Greenough, Hutt, Murchison, Wooramel, Gascoyne and DeGrey rivers, but is absent from numerous rivers within its range. The most likely explanation for the disjunct contemporary distribution is that C. cuneiceps has simply never inhabited the rivers from which it is conspicuously absent (e.g. Ashburton and Fortescue). Biogeographical, geological and palaeoclimatic evidence is presented to support this hypothesis. In the Murchison River, breeding was extremely protracted with recruitment occurring throughout the year. The largest female and male specimens captured were 96 mm total length (TL; 7.73 g) and 86 mm TL (5.57 g), respectively. Sex ratio was 1.09 females:1 male. Batch fecundity ranged from 46 to 454 (mean 167.5 ± 25.7 SE). Estimates for the length at which 50 and 95% of females first spawned were 36.4 and 44.3 mm TL, respectively. Craterocephalus cuneiceps is essentially a detritivore, but also feeds on aquatic invertebrates. Rainfall in the Murchison River catchment is unpredictable and pH, salinity and temperature are variable. A specialised diet, small size and young age at maturity and protracted spawning period, coupled with serial spawning and high fecundity, allows the numerical dominance of this species in competitive, harsh, arid and unpredictable desert environments. [ABSTRACT FROM AUTHOR]