Male Condition Factor Research Articles

Characterization of sperm quality in captive-bred barramundi (Lates calcarifer): Effect on spawning performance and paternal contribution in mass-spawning events

Barramundi (Asian sea bass, Lates calcarifer) is a species with a mass-spawning reproductive strategy whereby adults synchronously release their gametes into the water column. In captivity, this reproductive strategy usually results in uneven paternal contributions to each cohort of progeny, creating skews in family size that hinder the effectiveness of selective breeding programs. As sperm quality influences fertilization success and early larval development, we investigated the relationship between sperm quality and spawning performance. Accordingly, we assessed three established breeding cohorts. Sperm samples (n = 22) were collected by cannulation. Sperm motility was assessed using CASA, and sperm viability and DNA integrity were evaluated using dual-fluorescence stains by flow cytometry. Broodstock were induced to spawn across two consecutive nights, and offspring were collected at 2.5 h and 12 h post-fertilization (hpf) and 24 h and 48 h post-hatching (hph). Offspring were assessed for morphological abnormalities, and key morphological parameters were recorded. Offspring collected at 2.5 hpf and 24 hph were genotyped to determine their parentage and examine the relationship between sperm quality of individual males and offspring survival. Results highlighted that male condition factor (K) and sperm quality were highly variable within each breeding cohort. Males with a lower condition factor showed lower sperm motility and velocity. In contrast, males with a higher condition factor showed higher sperm motility and velocity but also higher levels of sperm DNA damage. While all males were capable of fertilization, males with a lower condition factor had greater paternal contribution. In this study, a reduction in skewed paternity was also found on Night 2 of spawning compared to Night 1. Moreover, males from Tank B, which had the lowest level of sperm DNA damage, had the most even paternal contribution. Conversely, highly skewed maternal contributions were reported across all spawning events. The results of this study suggest that additional complex dynamics and further unmeasured variables, such as spawning behavior, social hierarchy, and the spawning induction procedure, may also skew family sizes. Therefore, further development of artificial reproductive technology is recommended to gain greater control over individual contribution and overcome current breeding bottlenecks.

Assessment of Sexual Maturity and Spawning Biology of Channa punctata (Bloch, 1793): Conservation and Reproduction

The study was conducted in the freshwater station of the Bangladesh Fisheries Research Institute in Mymensingh between September 2021 and August 2022. Finding the sex ratio, sexual maturity, LWR, reproductive biology, fecundity, and histological examination of gonads of C. punctata were the main objectives of the present study. The correlation between length and weight was determined by analyzing the power function. Both sexes showed positive allometric growth and the correlation between length and weight was TW= 0.011TL3.09 for males and TW= 0.009TL3.11 for females. The mean condition factor for males was 1.09 (0.89 to 1.24), whereas the mean condition factor for females was 1.12 (0.95 to 1.25). In both cases, the condition factor was more than 1, indicating that the physical condition of both sexes was excellent. Among the 329 samples, 142 (43.16%) were male and 187 (56.84%) were female (male: female = 1: 1.32). The chi-square test showed a significant departure from the 1:1 ratio between the number of males and females within the sample months (df = 1, χ2= 0.01, p=0.05). When they reached first sexual maturity (L50), both sexes were of similar size, as evidenced by their lengths of 14.95 cm. The peak spawning season for both sexes was observed in June and July; however spawning season lasted from April to July. According to the study results, July was recorded the highest absolute fecundity (23609), while December recorded the lowest (1998).

Temporal variation in length-weight relationship, growth and condition factor of Acentrogobius viridipunctatus in the Mekong Delta, Viet Nam

The fish resource assessment has strongly related to their growth pattern estimated from fish length-weight relationship and condition factor, but these data on Acentrogobius viridipunctatus—a traded gobies in the Mekong Delta, Viet Nam have been limited. Consequently, the present study was performed for a year-round 2020 in order to provide knowledge on the length-weight relationship (LWR), growth and condition factor (CF) of this fish species. A total of 960 fish (432 females and 528 males) were caught at four coastal sites from Long Huu, Tra Vinh to Tan Thuan, Ca Mau. Due to high determination values of LWRs (r2 > 0.8), the fish weight could be estimated from a given fish length. Since the slope value (b= 2.64 ± 0.03) of LWR was <3 (p < 0.05), the goby exhibited negative allometry, implicating that practically fish was caught at a young age. The fish growth pattern did not vary with sex and size since males, females, immature fish, and mature fish displayed negative allometry. Likewise, this fish exhibited a negative allometric growth pattern in dry and wet seasons. The fish growth pattern did not vary with the studied site but changed with month, raging from negative allometry to isometry. The CF of males (1.04 ± 0.01) was significantly higher than that of females (0.99 ± 0.01) (t = 4.07, p < 0.001). Likewise, the CF in the wet season (0.96 ± 0.01) outnumbered in the dry season (1.09 ± 0.01) and was regulated by the season × site interaction (F = 53.60, p < 0.001). However, as the CF was close to 1⎯the well-being threshold, this fish adapted well to their habitat. The findings suggested that the size of fish caught should be increased for sustainable exploitation of this resource.

Aspects of the growth and reproductive biology of Oreochromis niloticus (Linnaeus, 1758) in a tropical Soda Lake, Lake Shala, Ethiopia

Morphometric relationships, condition factor (CF) and reproductive biology are significant tools in fish stock management, fish biology, physiology, conservation and ecology. Growth and reproductive strategy of Oreochromis niloticus were studied from 343 fish specimens collected from Lake Shala between January and December 2018. Fish samples ranged from 7.7 cm to 33.0 cm in total length (TL) and from 7.80 g to 708.21 g in total weight (TW) were collected using gillnets of 4, 6, 8, 10, and 12 mm mesh sizes. The length-weight relationship of O. niloticus was TW = 0.0104TL3.19, indicating positive allometric growth of the fish. The sex ratio (0.93:1) was insignificant from the ideal fish distribution of 1:1 (χ2 = 0.47, p &gt; 0.05). Mean CF for males, females and combined sexes was 1.04, 1.06 and 1.05, respectively and statistically insignificant (p &gt; 0.05). The spawning peak occurred in July (rainy) and February (dry) periods, as defined by ripe females and the breeding season. Absolute mean fecundity was 806 eggs and correlated positively with TL and TW of the fish (p &lt; 0.05) (F = 0.56TL2.29, R2 = 0.93, p &lt; 0.05; F = 18.83TW0.67, R2 = 0.90, p &lt; 0.05). The study provides the first detailed account of the morphometric relationships and reproductive biology of O. niloticus in Lake Shala, which can be used as baseline information for successive biological-based studies in Soda Lakes of Ethiopia.

Some Biological Aspects of Spotted Barb Barbodes binotatus (Valenciennes, 1842) in Tamblingan Lake

The biological aspects of the spotted barb, Barbodes binotatus (Valenciennes, 1842) in Tamblingan Lake were not published yet. This study aims to determine the biological aspects of spotted barb in Tamblingan Lake. Fish samples were captured using gill nets with various mesh sizes at five fixed stations monthly from January to December 2019. A total of 357 individuals of the spotted barb was collected, with the total length of the specimens ranging from 3.9 to 15.6 cm, and total weight varied between 0.93 and 60.30 g. The length-weight relationship for males and females were expressed as W = 0.0375L2.83 and W = 0.0272L3.02, respectively. The growth pattern for males and females was allometric negative and isometric, subsequently. The male-female sex ratio was 1.10:1, and the condition factor for males and females were 0.75-1.42 and 0.40-1.49, respectively. We observed male fish with gonad maturity stage I to IV. In contrast, female fish have gonad maturity stage II to V. The highest gonadosomatic index of male and female fish was found in September, indicating a peak of the spawning time. Fecundity ranged from 57-23897 eggs, with an average of 5901 eggs.

Reproductive biology of oriental sole, Brachirus orientalis, in Northern Persian Gulf

Reproductive characteristics of 300 specimens of oriental sole (Brachirus orientalis) in the Persian Gulf were studied by monthly sampling from August 2015 to July 2016. Male and female ages were between 3+ to 11+ and 3+ to 17+ years, respectively. The sex ratio was 1M:2.2F. The most frequent age group in males was 7+ and in females was 11+ years. The highest value of condition factor for males was observed in August. The minimum, maximum and average absolute fecundity were 22000, 174000 and 82000), respectively. The highest value of gonadosomatic index (GSI) for males was in April and October. The highest of hepatosomatic index (HSI) for males and females was in February, but was not significantly different from September and April (P>0.05). Based on GSI, egg diameter and monthly frequency distribution of different stages of ovarian maturation, it was determined that the fish has two prolonged spawning seasons, one from July to November with a peak in September (3.4) and the other from February to May with a peak in April (4.5). The long spawning season indicated that this fish is a multiple spawner with asynchronous ovaries.

Growth, length-weight relationship, and condition factor of NIFI (Oreochromis sp.) and Srikandi Tilapia (Oreochromis aureus x niloticus) at the grow-out stage in the high salinity brackishwater ponds

Tilapia strain of NIFI (Oreochromis sp.) and Srikandi (Oreochromis aureus x niloticus) are superior strain of tilapia that able to grow well in brackish water ponds. However, an increasing water salinity might have an impact on a series adaptation process on fish that leads to various morphological changes. This study aimed to analyze the growth and length-weight relationship of both tilapia strain in brackishwater pond with salinity of 25-30 ppt. Research was conducted in brackishwater pond in Losari, Brebes Regency. Fish were reared in 5x5x1 m3 hapas installed in the pond for four months. At the end of experiment period, body length and weight measurement were carried out for 26 males and 34 females of NIFI strain and 31 males and 28 females of Srikandi strain. The result showed that the highest growth rate was shown by Srikandi strain and the highest length was shown by NIFI. Positive allometric growth was found in the Srikandi females, while Srikandi males as well as NIFI tilapia males and females showed a negative allometric growth. Length-weight relationship on males and females of NIFI strain followed the formula of W = 0.0583L2,632 and W = 0.0452L2,665, respectively. Whereas, on males and females of Srikandi strain followed the formula of W = 0.0358L2,8545 and W = 0.0287L3,1580, respectively. There was a strong correlation between length and weight of fish from both strains with the R2 value ranged between 0.80 – 0.87. Condition factor of males and females of NIFI were 1.853 and 2.009, while Srikandi tilapia males and females were 2.308 and 2.665, respectively. Red NIFI and Srikandi tilapia are able to adapt in a high salinity level of brackish water pond.

Length weight relationship and relative condition factor of goby fish, Paracheaturichthys ocellatus (Day 1873) from the creeks of Mumbai

Length Weight Relationship of Paracheaturichthys ocellatus (Day1873) from the creeks of Mumbai was carried out from July 2010 to September 2011. The males ranged in the length of 66-182 mm and weight 1.152-54.801g while females ranged in the length 66-153mm and weight 2.209-38.383g. The juveniles ranged in the length range of 52-65mm and weight of 1.775-3-545g. The parabolic equation was W= -5.1742L3.1041 with high correlation of 0.9961 indicating that fish increased in body weight as it grows in total length in the total population. The coefficient of regression b was 3.1041 for all fishes combined together showing a positive allometric growth. The relative condition factor for males was 1.0126, females was1.0375 and 1.0013 for juveniles. Sex wise analysis of relative condition values revealed that mean Kn values in females (1.0375) was higher than that of males (1.0126). In present study Kn values were higher in males during pre-spawning period while in females it was during post spawning period. In males higher Kn values was observed in the length group of 106-115mm while in females it was 66-75mm. Relative condition factor was never less than 1 through the period of study hence it was in good condition irrespective of feeding or reproductive condition.

Feeding indices of Isfahan toothcarp (Aphanius isfahanensis) in Zayandeh River in Iran (Teleostei: Aphaniidae)

The feeding characteristics of Aphanius isfahanensis in the Zayandeh River of Isfahan Province were studied by collecting 440 specimens (220 males and 220 females) from July 2016 to May 2017. The specimens were anesthetized in 1% clove oil, fixed in 10% buffered formalin and transferred to the laboratory. The average condition factor for males was 1.7, for female 1.26 and showed significant difference between different months in both sexes ( P <0.05). The average length and weight for all specimens were 38.57±5.24mm and 1.00±0.41g, respectively. The average length of gut (RLG) for all fish was 0.54±0.17 during the year. The mean RLG in different length classes showed significant differences ( P <0.05). The highest Gastrosomatic Index value was in July (0.05) and the lowest in August (0.03) and showed significant differences in different months ( P <0.05). A total of 181 empty stomachs were observed amongst the 440 fish and there were significant differences in different months ( P <0.05). Therefore, it can be concluded that this is a carnivorous fish (mainly aquatic insect larvae) with a modest feeding throughout the year.

Determination of sexual dimorphism of African snakehead (&lt;i&gt;Parachanna obscura&lt;/i&gt;): morphometric and meristic parameters, weight-length relationship and condition factor

Artificial reproduction of fishes requires knowledge of their sexual dimorphism. African snakehead, Parachanna obscura , sexual dimorphism determination is difficult trough urogenital orifice examination. The aim of this study was to determine the sexual dimorphism of P. obscura using the parameters such as morphometric parameters, meristic parameters, weight-length relationship and condition factor. For the study, 30 specimens of P. obscura were collected from a swamp in Sakete a southeastern district of Benin. The fish weighed between 117 g and 251 g and their length were between 24.40 cm and 32.20 cm. At the end of this study, the different fins ray number were not significantly different (P>0.05). There was no significant difference among male and female fish (P>0.05) in total length, standard length, head length, snout length, snout width, head circumference and body circumference. Tail length had a significantly difference between male and female (P<0.05). The weight-length relationship indicated an allometric growth for the males and an isometric growth for the females. Significant difference was observed between male and female in condition factor (P<0.05). The male condition factor was the double of female condition factor. Condition factor, tail length and weight-length can be used for P. obscura sexual dimorphism determination. © 2017 International Formulae Group. All rights reserved. Keywords: Parachanna obscura , sexual dimorphism, condition factor, weight-length relationship

Size Structure, Growth Pattern, And Condition Factor Of Red Lolosi Fish (Caesio chrysozona, Cuvier, 1830) From The Bay Of Ratatotok Subdistrict, Southeast Minahasa Tenggara District

The research was conducted in December 2016 in Totok Bay, Ratatotok Subdistrict, with the aim to know the size structure, growth pattern and condition factor of red lolosi fish (Caesio chrysozona). It is expected that this research can provide basic information to monitor the presence of these fish in the future, especially in the territorial waters of Ratatotok. The name of red lolosi fish is a local name in North Sulawesi. Fish with the scientific name Caesio chrysozona is commonly found around the coral reefs and shallow rocky coastal waters. Data were collected in the field by taking a random sample of fish from the catch of fishermen who are still in a fishing boat. The number of fish samples taken to be analyzed were 66. Based on the measurement of 66 individuals of red lolosi, the structure size is as follows: male (51 head) with total length of 180 mm - 259 mm, length of fork 153 mm - 216 mm, and raw length 135mm - 200 mm. While body weight ranges from 71.38 gr - 217.18 grams and females (15 fish) with a total length range of 196 mm - 243 mm, fork length of 165 mm - 209 mm, and standard length of 149 mm - 185 mm. While body weight ranges from 110.22 gr - 193.99 gr. The growth pattern of red lolosi fish both male and female is a negative allometric growth pattern (b &lt;3) where the length of fish increase faster than weight gain. The condition factor of each individual male and female varies with the value of the male condition factor ranging from 0.8094 - 1.2547 and females ranged from 0.9668 to 1.0281. Because the value of K ranged 1 then the conclusion is that male and female of red lolosi fish have a less flat shape. This causes the loss of weight of fish due to the influence of food, age, sex and gonad maturity. ABSTRAK Penelitian dilakukan pada bulan Desember 2016 di Teluk Totok Kecamatan Ratatotok, dengan tujuan untuk mengetahui struktur ukuran, pola pertumbuhan dan faktor kondisi dari ikan lolosi merah (Caesio chrysozona). Ikan lolosi merah adalah nama lokal di Sulawesi Utara, dan ditemukan cukup berlimpah di sekitar terumbu karang dan perairan dangkal yang berbatu-batu di Teluk TotokPengambilan sampel di lapangan dilakukan dengan metoda sampling yaitu dengan cara mengambil sampel ikan secara acak dari hasil tangkapan nelayan yang masih berada dalam perahu nelayan. Jumlah sampel ikan yang diambil untuk dianalisis sebanyak 66 ekor. Berdasarkan hasil penelitian terhadap 66 individu lolosi merah, diperoleh struktur ukuran sebagai berikut: jantan (51 ekor) dengan kisaran panjang total 180 mm - 259 mm,. Sedangkan berat tubuh berkisar dari 71.38 gr – 217.18 gr, dan betina (15 ekor) dengan kisaran panjang total 196 mm - 243 mm, Sedangkan berat tubuh berkisar dari 110.22 gr – 193.99 gr. Pola pertumbuhan ikan lolosi merah baik jantan maupun betina adalah pola pertumbuhan allometrik negatif ( b &lt; 3) dimana pertambahan panjang ikan lebih cepat dari pertambahan beratnya. Faktor kondisi setiap individu jantan dan betina bervariasi dengan nilai faktor kondisi jantan berkisar 0.8094 - 1.2547 dan Betina berkisar 0.9668 - 1.0281.

Contribution to the knowledge of the feeding and growth biology of the Iranian cichlid,Iranocichla hormuzensis

AbstractGrowth parameters and feeding indices, such as condition factor (CF), of the Iranian cichlid, Iranocichla hormuzensis, the only native cichlid of Iran, were investigated during the period between August 2008 and August 2009. The estimated b value (the slope in length–weight equation) for males and females was 2.94, which is not significantly different from 3 that is indicative of isometric growth (p > 0.05). There was a significant difference (p < 0.05) between mean CFs of males and females. Males in the length group of 56–85 mm showed a higher CF than those in smallest (46–55 mm) and largest (86–100 mm) length groups. A total of 432 guts (217 of males and 195 of females) were investigated during the thirteen-month study period. The mean gut length, gut weight, relative gut length (RGL) and relative gut mass were significantly higher for males than females (p < 0.05). The RGL of males ranged between 1.12 and 8.24 (5.31 ± 1.26) and that of females between 0.58 and 10.43 (4.55 ± 1.53). Although I. h...

Length-weight relationship and condition factor of Macrobrachium amazonicum (Heller, 1862) (Decapoda, Palaemonidae) from a reservoir in Bahia, Brazil

Macrobrachium amazonicum (Heller, 1862) is a freshwater prawn occurring in rivers and reservoirs of Central and South America. Given its broad geographical distribution, the species shows great intraspecific morphological, reproductive, physiological and ecological plasticity. Furthermore, it also stands out for its economic importance, especially in the states of North (Para and Amapa) and Northeast Brazil. Despite the wide geographic distribution and economic importance of M. amazonicum, the biology of this species is poorly known, particularly in Northeast Brazil. We analyzed the length-weight relationships and condition factor of males and females of M. amazonicum. Specimens were collected monthly from September 2008 to August 2009 at the Pedra do Cavalo Reservoir, city of Cabaceiras do Paraguacu, State of Bahia. All specimens were sexed, measured and weighted. After that, length-weight relationships and the allometric (K) and relative (Kr) condition factors were calculated. Altogether 2,974 specimens were analyzed, 334 of which were males (11%) and 2,640 were females (89%). Females were larger and heavier than males. Males and females showed isometric and negative allometric growth, respectively. Monthly variations in the condition factor were similar for both sexes, and correlated strongly with rainfall regime and temperature in the region. Such variations are not correlated with the reproductive cycle of the species, but are probably correlated with food availability and somatic growth.

Notes on the reproductive biology of the Brazilian electric ray Narcine brasiliensis (Elasmobranchii: Narcinidae).

This study provides information on the reproductive biology of Narcine brasiliensis based on 105 individuals (72 females and 33 males) sampled in São Paulo State, Brazil. The total length at maturity for females was 318·9 mm and for males was 279·8 mm; pregnant females were observed only during summer and autumn. The peak of the gonado-somatic index for females and condition factor for males in the spring suggest a preparation for pregnancy and a mating period during this season. The capture of immature individuals indicates a need for management of the species in this region.

Reproductive biology of the Indian scad, Decapterus russelli (Ruppell, 1830) from Maharashtra waters, northwest coast of India

The length at which 50% of females of Decapterus russelli attain maturity was estimated at 153 mm. The presence of mature, ripe and spent gonads was observed from June to October and December to April indicating prolonged spawning season. The sex-ratio varied from 1:0.43 in 140-149 mm to 1:1 in 110-119 mm length groups. Month-wise distribution of sex-ratio indicated significant predominance of male at 5% in April, May and November. The absolute fecundity ranged from 29,986 to 1,52,123 eggs. Based on the GSI studies it is inferred that the species has a prolonged spawning season probably falling between December to March and June to October. The relative condition factor value was highest in January which indicates the peak spawning month. Length-wise condition factor of males and females were maximum in the length range of 100-229 mm. In the present study size of ova diameter ranged from 0.01 to 0.97 mm. The species seems to spawn twice in a season and the period between two spawning may not be a long one.

English

Length-weight relationship and Fulton&rsquo;s condition factor of Hemeri (Carasobarbus luteus) in Hoor Al-azim wetland (Khuzestan provinces, Iran) were investigated. During this study, from 2012 to 2013 more than 460 specimens&#39; of C. lutus were measured. Mean&plusmn;S.D length values for this species were 228&plusmn;15 respectively and maximum and minimum total length were 118 and 362 mm respectively. Mean &plusmn;S.D weight values for this species were 190&plusmn;91 g and maximum and minimum weight were 86 - 416 g respectively. The length-weight relation were calculated as W=0.0096 L3.11 (n=138,R2=0.97) for males, W=0.0079 L3.18 (n=271,R2= 0.94) for females, Y=0.0018L3.18 (n=466, R2 =0.96) for total fishes; verifying calculated b with 3 using Students t-test, there was no significant difference between calculated b and 3 (P&gt;0.05) and the growth pattern was isometric. The b value in the length-weight relationship did not differ significantly between males and females (t-test, P&gt;0.05). Fulton&rsquo;s condition factor (K) for male and female and total fish was 1.38&plusmn;0.12, 1.44&plusmn;0.20, and 1.40&plusmn;0.18 respectively and Students t-test showed no significant difference between Fulton&rsquo;s condition factor of males and females (P&gt;0.05). This study reports and provides basic information for fishery biologists in Iran. Key words: Carasobarbus luteus, length-weight relationship, Fulton&rsquo;s condition factor.&nbsp;

Seasonal distribution and Condition factor of Clarias gariepinus from polluted Oluwa River, Nigeria

The Condition factor (k) of the Clarias gariepinus species in Oluwa River, Nigeria was done. Samples were collected monthly over a two-year period from July 2010 to June 2012 and were identified using standard method. They were subjected to morphometric studies including determination weightand lengths. Condition factor was calculated in relation to sex and sizes. The mean condition factor for males exhibited a range of 0.81±0.03 - 1.97±0.33 (mean 1.34±0.10) while those of females exhibited a range of 0.64±0.00 - 2.00±0.21 (mean 1.31±0.09)and that for combined sexes ranged from 0.54±0.27 to 1.94±0.11 (mean 1.31±0.10). In relation to total length range (TLR), males had the highest condition factor at 34.00 - 36.90cm while the least was recorded in 70.00-72.90cm range. Females had the highest condition factor in the range 37.00- 39.90cm and the least at range 70.00-72.90cm. For the combined sexes, highest condition factor was recorded in the TLR 37.00-39.90cm while the least was also recorded in the TLR 70.00-72.90cm. The mean 'k' indicated that male fishes were not in good condition in the months of July, August and November. Generally, male fishes and smaller sized fishes were found to be better suited to the environmental condition than the female and bigger fishes.

Courtship Sounds Advertise Species Identity and Male Quality in Sympatric Pomatoschistus spp. Gobies

Acoustic signals can encode crucial information about species identity and individual quality. We recorded and compared male courtship drum sounds of the sand goby Pomatoschistus minutus and the painted goby P. pictus and examined if they can function in species recognition within sympatric populations. We also examined which acoustic features are related to male quality and the factors that affect female courtship in the sand goby, to determine whether vocalisations potentially play a role in mate assessment. Drums produced by the painted goby showed significantly higher dominant frequencies, higher sound pulse repetition rates and longer intervals between sounds than those of the sand goby. In the sand goby, male quality was predicted by visual and acoustic courtship signals. Regression analyses showed that sound amplitude was a good predictor of male length, whereas the duration of nest behaviour and active calling rate (i.e. excluding silent periods) were good predictors of male condition factor and fat reserves respectively. In addition, the level of female courtship was predicted by male nest behaviour. The results suggest that the frequency and temporal patterns of sounds can encode species identity, whereas sound amplitude and calling activity reflects male size and fat reserves. Visual courtship duration (nest-related behaviour) also seems relevant to mate choice, since it reflects male condition and is related to female courtship. Our work suggests that acoustic communication can contribute to mate choice in the sand goby group, and invites further study.

Fin size and associated fanning behaviour as indicators of reproductive status in male round gobies (Neogobius melanostomus)

Determination of male reproductive status in the round goby (Neogobius melanostomus) can be challenging because current metrics do not always reflect steroid production. In many fishes, fin size changes during the reproductive season; therefore, fins may provide additional information about reproductive status. In some species, fin size correlates with fanning behaviour; a trait common in fish species that exhibit male parental care as it is important for egg maintenance. Because male fanning begins before spawning, fanning also may play a role in pheromone dispersal and courtship, potential indicators of reproductive status. Initially, we examined which morphological metrics (head width, total length, condition, fin size) best delineated groups of reproductive and non-reproductive male gobies (determined using the gonadosomatic index, GSI). Surface areas of fused pelvic fins and caudal fins best separated these groups of males. Using video recordings of nest-guarding male gobies, we characterised both pectoral and caudal fanning behaviour. Rates of maximum caudal fanning (fin beats per minute) were higher than rates of pectoral fanning; however, caudal fanning overall was less frequent than pectoral fanning. Subsequently, we determined if fanning metrics were related to 11-ketotestosterone (11-KT), GSI and morphological traits. No relationship was found between any of the fanning or morphological metrics and GSI values or 11-KT. However, there was a significant relationship between the maximum pectoral fanning rate and condition factor of males. These findings suggest that relative fin size, but not fanning behaviours, may be useful metrics to measure reproductive status.

Condition factor and carapace width versus wet weight relationship in the swimming crab Callinectes danae Smith 1869 (Decapoda: Portunidae) at the Santa Cruz Channel, Pernambuco State, Brazil

The present work aims to study the size vs. weight relationship and the condition factor of a commercially important crab, Callinectes danae, from an estuarine complex located at Pernambuco State, Northeastern Brazil. After sampled, the specimens were measured on their carapace width (CW; mm) and weighted on their wet weight (WW; g). A total of 1,635individuals of C. danae were analyzed, being 881 males (53.8%) and 754 females (46.2%). Males were significantly larger and heavier than females (p < 0.05), the expected pattern to many crabs. The relationship WW vs. CW, described through the potency equation, was allometrically positive for both males (b = 3.12) and females (b = 3.02), a result also observed in other swimming crabs. The mean condition factor of males was 8.0 10-5 ± 1.5 10-5, and that of females was 11.5 10-5 ± 2.8 10-5, being significantly higher in females (p < 0.05), due to the fact that female gonads are heavier than that of males. The condition factor oscillated throughout the sampling year, for both sexes, which was related to the reproductive cycle.