Total Length Of Females Research Articles

Length frequency distribution, length-weight relationship and condition factors of Hilsa Shad, Tenualosa ilisha from Bangladesh

Hilsa shad, Tenualosa ilisha, a cherished and economically vital species, thrives in the waters of Bangladesh. It holds a prominent role in bolstering the nation's food security and influencing the ecological dynamics of aquatic ecosystems along the Bangladeshi coast and estuaries. This comprehensive study encompasses data collection efforts on the Hilsa fish species, conducted at 12 commercial landing centers throughout Bangladesh over the course of 2020. The study describes some fundamental components, including length frequency distribution, length-weight relationships, and condition factors, offers invaluable insights into the growth, health, and overall well-being of Hilsa population. Notably, the length-weight relationship analysis revealed size ranges of 11.5-59.2 cm and 11.0-49.0 cm total length for females and males, respectively. The observed b values indicated positive allometric growth (b > 3.00) for female population and negative allometric growth (b < 3.00) for male population in the length-weight relationship. Among the condition factors scrutinized, Fulton's condition factor emerged as the most reliable indicator for assessing the health and condition of the Hilsa population. This study offers valuable insights for biologists, aiding in the assessment of the species' status and providing essential information for fishery biologists and conservation biologists. Such insights are instrumental in the management and ultimate conservation of this iconic species in Bangladesh.

Reproductive biology of two small-bodied sharks, Carcharhinus coatesi and Rhizoprionodon acutus, in the Northern Territory, Australia

Sharks and rays are widely perceived to have slow reproductive rates and, thus, are often considered highly susceptible to population declines from commercial fishing. However, the reproductive biology of sharks is highly diverse, and some species can sustainably support significant commercial harvest. Small sharks are commonly caught and discarded as bycatch in several Australian and international fisheries. This represents either a wasted resource that could potentially be sustainably utilised, or a potential conservation issue if overharvesting occurs. This study examines the reproductive biology of two small-bodied sharks in the Northern Territory, Australia. Carcharhinus coatesi (n = 726) and Rhizoprionodon acutus (n = 179) were collected between May 2018 and November 2019 from commercial trawl fisheries. Maximum lengths in both species were higher in females than males (C. coatesi: F = 862 mm, M = 822 mm; R. acutus: F = 862 mm, M = 835 mm). Size at 50% maturation size C. coatesi: F = 655 mm, M = 664 mm; R. acutus: F = 682 mm. Size-at-maturity that the logistic model predicted for male R. acutus (715 mm) appears to represent size at full maturation and this study could not determine 50% maturation size. Litter sizes were small in both species, with C. coatesi producing 1–2 pups (mean 1.9) and R. acutus producing 1–4 pups (mean 2.8). Both species gave birth to large pups when compared to other shark species (C. coatesi: 370 - 450 mm; R. acutus: 315 – 400 mm), with C. coatesi size-at-birth being 47.6% of maximum female total length, while R. acutus size-at-birth was 41.5% of maximum female total length). Both species reproduced throughout the year, complicating estimation of the gestation period. The reproductive biology of C. coatesi and R. acutus showed considerable spatial and temporal variability when compared to studies from other regions and a past study from the Northern Territory in 1991. Although C. coatesi and R. acutus are currently abundant in the Northern Territory, the low fecundity of both species compared to other small-bodied sharks may limit their potential to sustain high levels of commercial harvest. Any expansion of commercial fishing for these species should be based on detailed consideration of their reproductive biology—in particular their low fecundity—to avoid the declines experienced by other formerly abundant elasmobranchs globally.

Reproduction parameters of hatchery reared grayling (Thymallus thymallus) females

European grayling (Thymallus thymallus) is an endangered salmonid fish species and its populations have decreased considerably in European waters in recent decades. One of the conservation measures applied to grayling is stocking with hatchery-reared fish. To advance the knowledge of grayling reproduction in the hatchery, husbandry data were systematically collected in the period from 2006 to 2015 during grayling spawning seasons and analyzed to quantify grayling female reproductive parameters such as fecundity, egg size, and embryo survival to the eyed egg stage. Data was collected for first time spawners (3 years old) and repeat spawners reared in the hatchery. Statistically significant differences were found for the number of eggs between first time spawners, producing on average 3600 eggs, and repeat spawners, producing on average 8000 eggs. Absolute fecundity was positively correlated to grayling female total length and weight for both first time and repeat spawners. However, relative fecundity did not correlate with these parameters. A positive correlation was observed between female total length and mean egg weight for repeat spawners, while the correlation was negative for first time spawners. Heavier eggs tended to have a higher rate of survival until the eyed egg stage, though the correlation was stronger for first time spawners than for repeat spawners. Due to the higher reproductive success of repeat spawners, it could be concluded that larger and older grayling females should be included in hatchery reproduction.

Correlatión analysis of morphometric parameters and reproductive indices of striped red snapper in the coastal zone of the department of Atlantic, Colombian Caribbean

Morphometric aspects, sexual ratio and reproductive activity of striped red snapper (L. synagris) in the Atlantic coastal zone were analyzed, based on the relationship between length and weight of the fish and weight of the gonad and reproductive indices. The coefficient of determination of the total length and total weight in females (R2=0.98) and in males (R2=0.91), gonad weight and total length in females (R2=0.73). indicating relationship between total length and total weight. Meanwhile, for males there was no relationship between gonad weight and total length (R2=0.49).

New Species of <i>Arrenurus</i> Dugès (Acari: Hydrachnidia: Arrenuridae) from Taiwan

This paper describes a new water mite, Arrenurus wengi sp. nov. from the Guantian Wetland, Tainan City, Taiwan. Male total length (μm) 639, width 528, and height 434, female total length 992, and width 860. Scanning electron microscope images illustrate the structure of male and female species.

Göynük Çayı (Bingöl, Türkiye)’nda Yaşayan ve Paradiplozoon bingolensis Civanova et al., 2013 (Monogenea: Diplozoidae) İnfestasyonuna Konak Olan Doktor Balık, Garra rufa (Cyprinidae)’nın Büyüme ve Üreme Özellikleri

This study was carried out to determine the growth and reproductive characteristics of Garra rufa Heckel, 1843 infested with Paradiplozoon bingolensis Civanova et al., 2013 in Göynük Stream, Bingol. A total of 267 G. rufa specimens were caught by a casting net between March 2015 and February 2016. The total length of G. rufa ranged from 8.5-19.1 cm and the total weights ranged from 5.8-58.7 g. The most intensive catching was in G. rufa population of 12.0-12.9 cm (30.0%) cm and 15.0-19.9 (25.2%) g in the groups. The mean condition factor was determined as 1.126±0.151 (0.607-1.646). The length-weight relationships were calculated as W= 0.0205 × TL2.758 (r2 = 0.891). The M: F ratio was 1:1.15. The sexual maturity length was recorded as 13 cm total length for males and 14 cm total length for females. Additionally, Paradiplozoon bingolensis was detected on only 218 G. rufa in this population. Of these positive samples, 173 P. bingolensis were isolated from male fish samples, while the females had 228 P. bingolensis. Therefore, female G. rufa specimens from this population were determined to be more predisposed to the infestation (p˂0.01).

Maternal investment in the viviparous caecilian amphibian Typhlonectes natans (Gymnophiona: Typhlonectidae)

Modern amphibians have an extraordinary diversity of reproductive modes including varieties of oviparity and viviparity. Oviparous and viviparous caecilian amphibians show high degrees of parental investment including dermato- and uterotrophy. We examined maternal investment and reproductive biology correlations of the aquatic viviparous caecilian amphibian Typhlonectes natans. Litter sizes ranged from two to ten pups, whereas litter masses averaged around 28% of maternal mass and pups reached up to 43% of the female total length. Maternal size was positively related to litter size and to the average pup body size. Although overall fecundity is reduced in viviparous teresomatan caecilian amphibians, as clutch size is decreased in comparison to oviparous ichthyophiid caecilians, a lower fecundity of viviparous taxa is compensated via uterotrophy leading to an increased offspring size and quality.

Biology of the thornback ray (Raja clavataLinnaeus, 1758) in the North Aegean Sea

AbstractThe study deals with aspects of the population dynamics in the thornback ray (Raja clavataL., 1758), one of the most abundant cartilaginous fish caught in the North Aegean Sea. Females accounted for 73.08% and males 26.92% of all individuals. Total length of females and males ranged between 50.2 and 89.9 cm (disc width: 33.4–62.0 cm), and between 43.1 cm and 82.7 cm (disc width: 30.7–64.2 cm), respectively. Relationships between total length (TL) and total weight (TW), and between disc width (DW) and total weight (TW) were described by the equations: TW = 0.0041 TL3.10and TW = 0.0178 DW3.03, respectively. Age data derived from vertebrae readings were used to estimate growth parameters using the von Bertalanffy function: L∞= 101.71 cm, K = 0.18 y−1, t0 = −0.07 y for males and L∞= 106.54 cm, K = 0.16 y−1, t0 = −0.28 y for females. The maximum age was 8 years for males and females. Total length at first maturity of males and females was 70.9 cm and 81.2 cm, respectively. Based on the gonadosomatic index and gonadal macroscopic observations, it was determined that the spawning period lasted throughout the year. Stomach content analysis showed that crustaceans (53.03% IRI) and teleosts (14.70% IRI) were the most preferred prey.

REPRODUCTIVE TRAITS OF NORTH AMERICAN CAJUN DWARF CRAYFISH (CAMBARELLUS SHUFELDTII) FROM THE NECHES RIVER NATIONAL WILDLIFE REFUGE

The Cajun dwarf crayfish (Cambarellus shufeldtii) is among the most broadly ranging dwarf crayfish species in North America. Little is known about the species' reproductive cycle in east Texas populations, and even less is known about the relationship between female body size and reproductive traits. This study seeks to characterize some reproductive traits of female C. shufeldtii as they correlate to body size. We recorded measurements of 23 berried specimens collected from an east Texas freshwater marsh, and established a positive correlation between female carapace length and number of eggs, as well as female total length and number of juveniles. Females were larger and had larger clutches than those reported from Louisiana. We also present some laboratory evidence for females reproducing multiple times in a single reproductive season.

Reproductive variables of Hypleurochilus fissicornis (Quoy & Gaimard, 1824) (Pisces: Blenniidae) on rocky intertidal zones in the South-western Atlantic

AbstractHypleurochilus fissicornis is a resident species of the intertidal and subtidal zones of Mar del Plata, Argentina. The specific reproductive biology was studied by means of both microscopic and macroscopic analyses. A total of 212 males and 223 females were analysed. Specimens were dissected and their gonads and livers were removed. The gonadosomatic and hepatosomatic indexes and the condition factor were calculated on a monthly basis. Hypleurochilus fissicornis breeds in rocky intertidal areas, and exhibits low fecundity with benthic eggs and parental care. Size at first maturity (L50) was estimated at 53.66 and 55.83 mm total length for females and males, respectively. The spawning season takes place between December and April.

Growth parameters of invasive gibel carpCarassius gibelio(Bloch, 1782) in Lake Marmara (Turkey)

AbstractThe objective of this study was to determine growth parameters, such as age–length and length–weight relationships, as well as condition factors and sex ratio, of theCarassius gibelio(Bloch, 1782) population in Lake Marmara (western region of Turkey), which is one of the most important fishing areas. Fish were caught on a monthly basis by gillnets and trammel nets (mesh size 10–50 mm) between March 2012 and February 2013. A total of 1058 specimens (809 females and 249 males) were examined. The female–male ratio was 1:0.31. The maximum age was determined as VI and V for females and males, respectively. The total length of females and males ranged from 10.0 to 27.5 cm and from 10.2 to 24.0 cm, respectively. Their weight varied from 17.1 to 378.4 g and from 17.7 to 244.9 g, respectively. Length–weight relationship parameters werea= 0.014 andb= 3.040 for females anda= 0.015 andb= 3.039 for males. Von Bertalanffy growth parameters of theC. gibeliopopulation were as follows: L∞= 35.86 cm, k = 0.189 year−1, t0= −1.238 years. Minimum and maximum condition factors were 1.56 for females in October and 1.82 in May and 1.67 for males in September and 1.94 in January.

Feeding habits of oriental sole (Brachirus orientalis) on the Bushehr coast of the Persian Gulf

Abstract The feeding habits of oriental sole, Brachirus orientalis (Bloch & Schneider) were investigated using 300 male and female specimens collected from coastal waters of Bushehr Province (Persian Gulf) between June 2015 and July 2016. The total length of females and males ranged from 16.2 to 38.5 cm and 14.1 to 29.1 cm, respectively. Of the total number of stomachs examined, 225 were empty (vacuity index = 77%). This index varied significantly over the year (P < 0.05), with maximum values in April and September and minimum in October and May. The B. orientalis diet was composed of nine prey species belonging to five classes. The most important prey items were Crustacea and Mollusca (Bivalvia and Gastropoda). Diet composition showed little seasonal variation, and Crustacea, Bivalvia, and Gastropoda were the most important prey items in all seasons. Sex did not appear to have any significant effects on dietary composition, and the main prey items were consumed by both males and females (P > 0.05).

Pleopodal fecundity of narrow-clawed crayfish (Pontastacus leptodactylus Eschscholtz, 1823)

ABSTRACT The pleopodal fecundity of Pontastacus leptodactylus from Hirfanlı Dam (Turkey) was investigated. Reproductive period, length at first maturity, as well as the number, weight and diameter of pleopodal eggs were determined. The study was conducted monthly at six different stations from June 2017 to May 2018. Berried females were observed between December and May. L50 length at first maturity of the female crayfish population in the lake was estimated as 9.04 cm and this value is below the applied 10 cm Minimum Landing Size (MLS). The mean egg number of the population was 240.18, the mean egg weight was 0.0122 g and the mean egg diameter was 2.702 mm. While an increase in female total length had a positive effect on mean total egg number, sampling period (progressive incubation period from December to May) caused negative effects. The mean total egg number for 1 mm total length was found to be 2.18. When the mean pleopodal egg number of the crayfish population in Hirfanlı Dam Lake was compared with populations of P. leptodactylus in other localities it was concluded that the stock is quite productive.

Spatial and temporal segregation of yellow perch in southern Lake Michigan

AbstractHistorically, yellow perch, Perca flavescens Mitchill held great recreational and commercial importance to the Lake Michigan fishery. Unfortunately, fluctuations in lake‐wide abundances in the past four decades created inconsistencies in catch. As adults, yellow perch have been commonly observed to swim great distances suggesting there is likely to be partitioning of the population within the lake. The objective was to determine whether population demographics of yellow perch in the Indiana waters of Lake Michigan were consistent with a single population. Seasonal population demographics of yellow perch collected from the Indiana waters of Lake Michigan in 2009, 2011 and 2012 were compared. Catch‐per‐unit‐effort of female yellow perch increased during later sampling periods across years. Similarly, total length of females and males increased 10% throughout the year. The proportion of females increased from 20% at the beginning of the survey period to 95% at the end. A few larval yellow perch were collected. These data suggest that Indiana waters of Lake Michigan are not a primary spawning area, rather these waters serve as a feeding or recovery area for post‐spawned yellow perch, particularly females.

First fecundity observations on female copepods from three northern Patagonian lakes (Pellaifa, Calafquén, Panguipulli; Chile)

Abstract The crustacean zooplankton in Chilean Patagonian lakes is characterized by a marked dominance of calanoid copepods when under an oligotrophic status. The aim of the present study was to analyse the number of eggs and the relation of that feature with the total length of females of calanoid and cyclopoid copepods reported in three northern Chilean Patagonian lakes. The calanoid copepods found were Boeckella gracilipes in Lake Pellaifa and Tumeodiaptomus diabolicus in the lakes Panguipulli and Calafquén, whereas the cyclopoid Mesocyclops araucanus was found in the lakes Pellaifa and Calafquén. For calanoid copepods, high egg numbers were found and thus also a high value for the ratio of egg number per female length in Lake Panguipulli, whereas for M. araucanus a high value was found in Lake Pellaifa. These differences would presumably be associated with community structure, specifically predator-prey relationships and possibly other interactions, as, e.g., potential interspecific competition.

Reproductive biology of the mutton hamlet on the coast of Pernambuco, northeastern Brazil

This paper focuses on the reproductive biology of the Mutton Hamlet, Alphestesafer, a fish belonging to the family Epinephelidae, and aims to provide information on the main reproductive parameters of the species on the north coast of the state of Pernambuco, northeastern Brazil. From a total of 783 individuals, collected between March 2007 and June 2010, and from February to November 2014, the gonads of 322 fishes (235 females and 87 males) were analyzed, for the identification of sex and maturational stages. Females were more abundant and larger than males, with a sex ratio of 2.4 females: 1 male, during the reproduction season. The size at first maturity (L50) was estimated at 16.8 cm total length for females, and 16.2 cm for males. The gonadosomatic index (GSI) indicated that a reproductive cycle occurs all year round, while reproduction takes place from June to November. The fecundity of Alphestesafer ranged from 105,317 to 270,192 oocytes, averaging 173,458 oocytes. The females are more abundant than males due to the process of protogyny and also because individuals are regularly captured at growth stages above the L50, being a positive aspect for the sustainability of the fishery. According to the GSI, the species presents a split-type spawning with two peaks occurring throughout the year.

Reproductive biology of the Brazilian blind electric ray Benthobatis kreffti (Chondrichthyes: Narcinidae)

ABSTRACT This study provides information on the reproductive biology of the Brazilian blind electric ray Benthobatis kreffti, endemic to southern and southeastern Brazil. Individuals were caught by bottom trawl carried out in 2003 and 2007, at 492-501 m depth off the São Paulo State continental slope. A total of 152 females (115-299 mm) and 144 males (91-243 mm) were sampled. Maturity was first observed at 177 and 162 mm, with total length at 50% maturity of 191 and 176 mm in females and males respectively. Uterine fecundity ranged from 1-3 and was not related to female total length. Size at birth estimated from the largest near-term observed embryos and smallest free-swimming ray was 91-100 mm. The low fecundity observed is typical of deepwater elasmobranch species, as well as late maturity in comparison with costal species. The relatively large size-at-birth suggests that this species invests more in length of each embryo than in litter size, increasing the offspring’s survival chance. In this context, these parameters highlight the vulnerability of this and other deepwater species to non-natural death, mostly caused by deep-sea fisheries.

Responses to mass selection in a domesticated population of snakeskin gourami, Trichopodus pectoralis, Regan 1910, and confounding effects from stocking densities

Genetic improvement by farmers is beneficial for species with low economic value, as a way for farmers to access good seed stocks, and to maintain genetic diversity. However, concern has been raised whether the simple selection method is effective for the currently poorly managed culture stocks with long domestication history. In this study, mass selection was performed in a culture stock of snakeskin gourami, Trichopodus pectoralis, Regan 1910, to determine whether a simple mass selection would give positive selection response. The selection was performed based on total length, whereby the cut-off total length for females was 20.80 cm while all males were recruited due to limited number of morphologically distinct males available. This resulted in selection differentials of 1.44 cm for total length in females, and 0.20 cm in males (realized selection intensity was 1.412 and 0.210 for females and males, respectively). The results of the growth trial showed a positive but low selection response (P < .01; 2.90% of the control). The correlated responses for body weight, average daily growth, and average growth coefficient were positive (2.13–9.06% of the control) whereas a correlated response for survival rate was negative (−4.6% of the control). In addition, the high stocking density used in the growth trial obscured the selection response, which was more apparent at low stocking densities. The recommendation was made that mass selection has potential to improve growth of snakeskin gourami and thus should be introduced to farmers, and that the selection intensity should be increased.

Population structure and reproductive biology of Haemulopsis corvinaeformis (Perciformes, Haemulidae) in the south coast of Pernambuco, northeastern Brazil

ABSTRACT: Roughneck Grunt (Haemulopsis corvinaeformis Steindachner, 1868) is the second most important species caught as bycatch of the shrimp fishery in Pernambuco, Northeastern Brazil. However, the population dynamic of this species is poorly known in the region. The aim of this study was to describe aspects of the population structure and reproductive biology of the H. corvinaeformis, providing important information for the development of sustainable management practices. Specimens were collected monthly from August 2011 to July 2012 and quarterly from October 2012 to June 2014. A total of 1,140 individuals was collected; 340 males (29.8%), 391 females (34.3%), and 409 were immature and could not be sexed (35.9%). Total length ranged from 7 to 25 cm. In general, total length of females [12.85 ± 2.49 cm (mean± SD)] and males [12.72 ± 2.46 cm (mean ± SD)] were similar (p &gt; 0.05). The proportion of males and females was similar along the year, except in March. The relationship between total length and total weight was statistically significant (p&lt; 0.05), showing an isometric growth. The (GSI) coupled with the distribution of maturational stages suggests that females reproduce all year around, with a peak during October-November. The length at first maturity (L50) was estimated at 11.88 cm for females and 11 cm for males.

Relationships between total length and otolith size of bluefish Pomatomus saltatrix (Linnaeus, 1766) in the Marmara Sea of Turkey

In the present study, bluefish, Pomatomus saltatrix, was monthly collected from commercial fishing boats operating in the Marmara Sea between January and December 2014. The relationship between total length and otolith size of 346 bluefish samples were examined. Total lengths of females, males and unidentified samples were ranged from between 13.2-37.0, 12.3-34.8 and 13.0-31.6 cm, respectively. Otolith lengths were between 3.82-12.60 mm and otolith width were between 1.59-4.34 mm for all samples. It was found that there is a strong correlations between otolith length-total length (r2 =0.88) and otolith width-total length (r2 0.81).