Mean TL Research Articles

Biology, Population Parameters, and Ecology of the Sergestid Shrimp Acetes intermedius in Damilisan, Miagao, Iloilo, the Philippines

This study investigated the biology, population parameters, and ecology of the sergestid shrimp (Acetes) in Barangay Damilisan, Miagao, Iloilo, the Philippines, by collecting samples for biological analyses and analyses using FiSAT II software. Based on morphometric evaluation, the sergestid shrimps present in the study site were identified as Acetes intermedius. Mature and near-spawning of the 180 specimens examined for ovarian maturity were > 50% in January, February, and April 2022. Size at sexual maturity was recorded at lengths ranging from 21.90– 23.10 mm. The highest mean TL and CL were 20.49 ± 1.84 and 5.32 ± 0.56 mm, respectively, in January 2022. The length-frequency data showed that the highest frequency was 18.50–20.40 mm. The male-to-female sex ratio was 1:2; wherein females dominated the males. The highest frequency for females ranged from 20.50–22.40 mm (TL). Estimated population parameters of A. intermedius were L∞ = 30.98 mm, K = 1.900 yr–1, Ø’ = 3.26 yr–1, tmax= 1.6 yr–1, M = 3.93 yr–1, F = 4.07 yr–1, Z = 8.00 yr–1, E = 0.51, E0.1 = 0.517, E0.5 = 0.349, Emax = 0.691, L₅₀%/Lc = 13.45 mm, and L₇₅% = 14.57 mm with a unimodal type of recruitment pattern. The value obtained for the exploitation rate was above 0.5, hence suggesting that the Acetes stocks in Brgy. Damilisan faced overexploitation. These results provide information that can be used to properly conserve, utilize, and manage the Acetes fishery industry in Miagao, Iloilo, the Philippines. Keyword.

Cisco population characteristics in Wisconsin lakes in relation to lake‐ and landscape‐level factors

AbstractObjectiveDeclines in Cisco Coregonus artedi populations in some inland lakes have prompted assessments of Cisco occurrence and extirpation risk in relation to various stressors to identify refuge lakes and factors that promote Cisco persistence. However, most previous assessments have focused on presence–absence of Cisco rather than examining how population characteristics, such as relative abundance or growth, might change in relation to lake‐ and landscape‐level environmental factors. Consequently, our specific objectives were to identify important environmental factors explaining variation in Cisco relative abundance and growth and to determine whether population metrics describing size and age distributions were related to relative abundance in Wisconsin inland lakes.MethodsCisco were collected from 48 inland Wisconsin lakes during 2011–2015 using vertical monofilament gill nets and population‐specific relative abundance estimates (catch per unit effort [CPUE]) were quantified as the number of individuals per gill‐net night. Sagittal otoliths were removed from a subsample of Cisco for age estimation and growth was indexed as mean total length (TL; mm) at age 2. Length and age data were used to develop a suite of metrics describing size and age distributions of each population. Random forest models were used to evaluate relationships between 10 biologically relevant predictor variables representing variation in physical, climatic, catchment, and limnological characteristics and Cisco CPUE and growth. Pearson correlations were used to determine whether population characteristics were related to CPUE.ResultCisco populations exhibited large variation in relative abundance, growth, and size and age distributions. Best‐fit random forest models explained approximately 25% of the variation in Cisco CPUE and 46% of the variation in growth. Growing degree‐days and variables associated with availability, quality, and quantity of suitable oxythermal conditions were identified as important predictors of both Cisco CPUE and growth; CPUE was also identified as an important predictor of growth. Mean TL and mean TL at age 2 were negatively related to Cisco CPUE, whereas mean age, number of age‐classes present, and maximum observed age were positively related to CPUE.ConclusionOur results suggest that maintenance of suitable oxythermal habitat conditions may be critical to conserving abundant Cisco populations. Our assessment also provides insights on how Cisco populations may respond to environmental and anthropogenic stressors, which could aid ongoing and future conservation and management efforts in Wisconsin and elsewhere.

Size Preference of Live Fish Prey in the Pellet-Consuming Pikeperch

The production of pikeperch in a recirculation aquaculture system (RAS) is of growing importance. However, the use of combined technologies may also be justified, especially in countries with larger pond areas. However, this requires the most effective adaptation of pellet-consuming individuals to pond conditions. Foraging training, a form of environmental enrichment to compensate for the poor environment in hatchery rearing, can play a major role in this. The aim of our study was to investigate the prey size preference already observed in wild pikeperch, during prey capture by intensively reared naive individuals. We investigated predation success, latency, number of attempts during the process, and size distribution, in a total of 152 foraging trials of 38 pikeperch fingerlings (mean TL = 90.65 mm) at three different prey sizes (predator–prey length ratio (PPR): 0.11, 0.22, 0.33). Although predation on medium–large prey was more successful overall, it was achieved in more attempts and with greater latency. Small prey was captured with the fewest attempts. These results suggest that when calculating prey size in the foraging training of pikeperch, it is recommended to use a 0.11–0.22 PPR less than the optimal PPR described for wild individuals.

Capture Is Predicted by Behavior and Size, Not Metabolism, in Muskellunge

AbstractFish that strike angling lures often have a set of characteristics that predispose them to capture. Vulnerable fish may then be removed from a population, either through harvest or incidental mortality, and in turn leave individuals in a population that are less vulnerable to angling. Over time, the removal of vulnerable individuals can erode capture rates, possibly resulting in evolutionary changes if traits that result in capture correlate with characteristics such as fecundity or growth. We sought to define the mechanisms driving individual angling vulnerability in Muskellunge Esox masquinongy, with the intent of informing management activities to conserve populations. The behavior of individually identified Muskellunge (n = 68; mean TL = 310.2 mm; range = 229–350 mm) was assessed using standard open‐field tests; the fish were then stocked into earthen‐bottom ponds to assess angling vulnerability. After angling, all captured fish and a subset of uncaptured fish were assessed for metabolic parameters. Results indicated that larger Muskellunge displaying low levels of exploration and aggression were preferentially captured. Behaviors such as boldness and activity did not influence capture, and metabolic parameters did not differ between captured and uncaptured fish.

Streamwide Evaluation of Survival and Reproduction of MYY and Wild Brook Trout Populations

AbstractBrook Trout Salvelinus fontinalis have been introduced across the western USA, where the species competes with and often replaces native salmonids. Nonnative Brook Trout are difficult to eradicate; thus, new removal strategies are needed. One novel methodology couples the partial suppression of wild Brook Trout with the replacement of MYY Brook Trout (males with two Y chromosomes). If MYY fish survive to reproduce with wild female Brook Trout, their progeny will be 100% male, which eventually shifts the sex ratio and theoretically extirpates the population. However, the effectiveness of this approach depends on survival and reproduction of MYY fish relative to the surviving wild conspecifics. From 2018 to 2020, we annually removed an estimated 45.7% of wild Brook Trout from three streams in New Mexico and stocked fingerling MYY Brook Trout (mean TL = 94 mm; range = 61–123 mm) targeting 50.0% of wild annual abundance estimates. Annual survival for MYY and wild Brook Trout was similar in Leandro Creek (MYY = 0.63 and wild = 0.63) and Rito de los Piños (MYY = 0.37 and wild = 0.46) but differed in Placer Creek (MYY = 0.28 and wild = 0.75). During spawning, we evaluated the reproductive potential of MYY Brook Trout by comparing the percentage of sexually mature male Brook Trout comprised of MYY fish to the percentage of hybrid (MYY × wild) F1 progeny. By the second spawning season (2019), MYY fish comprised 59.8, 50.4, and 34.5% of milt‐producing Brook Trout, which resulted in 55.1, 33.3, and 0% hybrid progeny in Leandro Creek, Rito de los Piños, and Placer Creek, respectively. We demonstrated that MYY fish exhibit similar vital rates compared with wild conspecifics in two of three streams; however, differences among streams highlights unforeseen variables that influence MYY survival and reproduction. The study offers promising results of the MYY approach for potentially eradicating unwanted Brook Trout populations.

Factors Predictive for Immunomodulatory Therapy Response and Survival in Patients with Hypersensitivity Pneumonitis-Retrospective Cohort Analysis.

The aim of the present retrospective study was to establish predictive factors for treatment success and survival advantage in HP patients. We analyzed the short-term treatment outcome and overall survival in consecutive HP patients treated with prednisone alone or combined with azathioprine. The study group consisted of 93 HP patients, 54 (58%) with fibrotic HP and 39 (42%) with non-fibrotic HP. Mean (± SD) VCmax % pred. and TL,co % pred. before treatment initiation were 81.5 (±20.8)% and 48.3 (±15.7)%, respectively. Mean relative VCmax and TL,co change after 3-6 months of therapy were 9.5 (±18.8)% and 21.4 (±35.2)%, respectively. The short-term treatment outcomes were improvement in 49 (53%) patients, stabilization in 16 (17%) patients, and progression in 28 (30%) patients. Among those with fibrotic HP, improvement was noted in 19 (35%) cases. Significant positive treatment outcome predictors were fever after antigen exposure, lymphocyte count in broncho-alveolar lavage fluid (BALF) exceeding 54%, RV/TLC > 120% pred., and ill-defined centrilobular nodules in high-resolution computed tomography (HRCT). An increased eosinophil count in BALF and fibrosis in HRCT were significant negative treatment outcome predictors. The presence of fibrosis in HRCT remained significant in a multivariate analysis. A positive response to treatment, as well as preserved baseline VCmax (% pred.) and TLC (% pred.), predicted longer survival, while fibrosis in HRCT was related to a worse prognosis. Immunomodulatory treatment may be effective in a significant proportion of patients with HP, including those with fibrotic changes in HRCT. Therefore, future trials are urgently needed to establish the role of immunosuppressive treatment in fibrotic HP.

Are the Temporal Changes Observed in the Reproductive Biology of the Estuarine Conguito Sea Catfish Related to Increased Small‐Scale Fishing Effort on the Northwestern Pacific Coast of Mexico?

AbstractBiological parameters relating to the reproductive biology of Conguito Sea Catfish Cathorops liropus were investigated in 1979–1984 and 2015–2018 from an estuarine system on the northwestern Pacific coast of Mexico. In the first period, the spawning season occurred during the dry–warm season (April–June), according with the percentage of mature females and the highest gonadosomatic index (GSI) values. Mean TL was 12.3 cm, two cohorts were found, length at maturity was 18.6 cm, and fecundity was 24.47 oocytes/organism. In the second period, the spawning season extended to the rainy–warm season (July–November), as reflected by the percentage of mature females and the GSI values. Mean TL was 11.6 cm, length at maturity decreased to 17.1 cm, and fecundity decreased to 20.67 oocytes/organism, indicating a reduction in the size‐based indicators and a change in the spawning period and reproductive effort as time passed. The number of fishing skiffs increased from 1,103 in 1980 to 2,434 in 2019, representing a 220% increase, and the landings increased from 400 to 3,432 metric tons in the same period. Temporal trends in surface water temperature, salinity, and the Oceanic Niño Index did not explain the observed changes between the study periods. These results suggest that the observed changes in the reproductive potential of Conguito Sea Catfish have been at least partially due to fishing.

Seasonal Abundance and Length Patterns of Brown and White Shrimp in Texas Estuaries and Nearshore Waters: Implications for Population and Fishery Dynamics

AbstractPenaeid shrimp are a major contributor to commercial landings in the Gulf of Mexico, with white shrimp Litopenaeus setiferus and brown shrimp Farfantepenaeus aztecus making up the bulk of the landings off Texas. In this study, we examined seasonal trends in white and brown shrimp population demographics (relative abundance, monthly proportion of catch, and length) and their relationship with water quality parameters (water temperature and salinity) across a 36‐year fishery‐independent data set for Texas estuarine and nearshore waters. The primary findings of this analysis were consistent negative trends in seasonal mean TL (April–August) for brown shrimp. These negative trends resulted in decreases in mean TL of up to 20 mm across the time series. Additionally, growth coefficients calculated on an annual scale for brown shrimp showed negative trends as well. White shrimp did not show the same consistently negative trends in mean length or growth. Although expected seasonal trends in CPUE and monthly proportions of catch were observed, the analysis showed few convincing or consistent annual trends in these metrics for either species. We suggest that the differing trends in mean length (i.e., between species) may be explained by summer water temperatures exceeding the optimum growth range for brown shrimp in the latter part of the time series examined here. Such trends in mean length for the brown shrimp population may have implications for population fecundity and may affect the value and efficiency of shrimp harvest in commercial fisheries, though this has yet to be seen. Nevertheless, managers should remain vigilant to any continued negative trends in brown shrimp length and their potential impact on the population and fishery dynamics.

Acute Inhalation of Generator Exhaust-Fumes May Impair Learning and Memory in Mice

The study assessed the effects of acute inhalation of generator exhaust fumes on the anxiety-associated learning and memory (L&M), and motor coordination in mice. Twenty-four mice were divided into 4 groups. First and second groups were tested for motor coordination (beam walk) and L&M (Elevated Plus Maze, EPM) respectively. Mice in the experimental groups were exposed to the generator fume for 30min., 1hr., and 2hrs respectively before the tests. In Day 1, experimental animals showed significant decrease in the mean TL (13.4 ± 1.5sec.) and an increase (73 ± 8.4sec.) at 30min. and 1hr respectively, when compared to their controls (28.6 ± 5.2sec.) and (21.8 ± 4.4sec.). In day 2, there were significant increase in the mean TLs during the 30min. (48.4 ± 12.8sec.) and 2hrs exposures (66.8 ± 15.3 sec.), when compared to their controls (13.6 ± 1.9sec.) and (22.6 ± 6.6sec.) respectively. The result suggests decreased ability of the exposed mice to learn and recall the new behaviour. There was significant increase in the mean %COHb level of the experimental group (2.06 ± 0.012%) when compared to the control (0.76 ± 0.089%). Exposure to CO from the generator exhaust fumes impaired learning and memory in mice.
 Keywords: Carbon monoxide, Learning and Memory, Motor coordination, Elevated Plus Maze, Beam walk.

Morphological Characterization of Lithognathus mormyrus (Linnaeus, 1758) Populations in the Southern Black Sea (Turkey)

Morphological characteristics such as meristic counts and body shape have long been used in stock identification. Fifty striped seabream, Lithognathus mormyrus, individuals were sampled from the south Black Sea between January 2020 and November 2020. Morphometric characteristics were given as the percentage of total length (TL%). Species identification and shape differences between sexes of striped seabream were analyzed by different statistical methods. The biggest maximum length and weight values (TL=310 mm for TW=399.73 g) were found for the southern Black Sea in this study. The mean TL of female individuals (X=205.26 mm) was found higher than male individuals (X=199.10 mm). The TL% ratio of head length was found as 24.45% for all individuals. In this study, isometric growth (t=2.009, p>0.05) was determined for all individuals and the length-weight relationship (LWR) was found as W=0.013TL3.003 (r²=0.983). This study revealed that the morphological characteristics of L. mormyrus differ significantly between female and male individuals and the species may be a good example of sexual dimorphism. 

Biological and Reproductive Indices of Mystus bleekeri (Day, 1877) in Open Water Body (Dekhar Haor) of Bangladesh

Some biological and reproductive aspects of the Mystus bleekeri from Dekhar Haor were investigated. From the commercial catches, a total of 600 sample collections were performed on a monthly basis from July 2017 to June 2018. Total length (TL, cm), body weight (W, g) and individual’s sex were identified between 216 male (36%) and 384 female (64%) fish (ratio 1.00: 1.78). Mean TL and W of samples were 14.85±3.38 cm and 27.54±15.76 g, respectively. The TL of male and female ranged from 6.9-21.3 and 7.80-24.60 cm, respectively; and W ranged from 5.3-63.3 and 6.70-76.40 g, respectively. In length–weight relationship of this fish depicted a negative allometric growth (b=2.408) with a condition factor (Kn) of 1.04±0.11. Fish of 16.00-16.90 and 10.00-10.90 cm length groups demonstrated the highest (1.45±0.23) and lowest (0.89±0.18) Kn values, respectively which was significantly varied among different length groups. Monthly study of gonadosomatic index showed two peaks in the month of May-June and November for both sexes. The results of this study provide baseline data on some biological aspects of M. bleekeri, which would be useful in predicting the responses of M. bleekeri populations in Dekhar Haor. 

Green morays (Gymnothorax funebris) have sedentary ways in mangrove bays, but also ontogenetic forays to reef enclaves

Surprisingly, little is known about basic life history of the largest moray eel species in the Caribbean region, the green moray eel (Gymnothorax funebris). Sixteen eels were captured from the mangrove fringe in multiple bays on St. Croix, USVI, implanted with coded acoustic transmitters, and their movements were tracked for up to 11 months using an array of 37 stationary acoustic receivers. They exhibited high site fidelity in the bays during their residence, using the same general parts of individual bays and did not switch bays except for one individual. There was no relationship between eel size (mean TL = 83 cm, range = 54–126 cm) and home range size (mean area of 95% KUD = 5.8 ha ± 0.7 SE). Most individuals were more frequently detected at night than during the day suggesting greater nocturnal activity. Several of the larger eels (mean TL = 93 cm ± 5.9 SE) showed clear and permanent emigration tracks out of the mangrove estuary to coral reef habitats offshore. For some individuals, these habitat shifts were preceded by exploratory movements away from the eel’s typical home range the night before emigration. All final emigration events took place nocturnally, happened during a single night, and occurred during months from December to May. Mean emigration speed was 3.4 km/h. This study is the first documentation of an ontogenetic habitat shift in moray eels, as well as the first determination of home range size for this species and their site fidelity in mangrove habitats.

Alternative Prey Reduces Largemouth Bass Predation Mortality on Newly Stocked Channel Catfish Fingerlings

AbstractManagement agencies commonly stock Channel Catfish Ictalurus punctatus as advanced yearlings instead of fingerlings (age 0) to help reduce potential predation mortality despite uncertainty regarding the degree to which predation limits fingerling poststocking survival. To better understand whether fingerling survival during the first 7 d after stocking—when predation risk is likely greatest—could benefit from the presence of alternative prey fish, we conducted an experiment in 0.4‐ha ponds (N = 18; 6 ponds/treatment) that measured fingerling (TL range = 56–186 mm) survival in ponds with predators only (adult Largemouth Bass Micropterus salmoides; mean TL = 327 mm; SE = 21), with predators and alternative prey fishes (Bluegill Lepomis macrochirus and Goldfish Carassius auratus), or with neither (i.e., control ponds). Without alternative prey, fingerling Channel Catfish survival 1 week after stocking was significantly (P < 0.01) lower (89%) than in the ponds with alternative prey (98%) or in the control treatment with no predators (97%). Our experiment also indicated the potential for alternative prey to promote fingerling survival by reducing water clarity, not just by serving as a buffer from predation. Further research, however, is needed to determine the degree to which our findings apply to larger ecosystems and to learn whether stocked fingerlings survive well enough after the initial stocking period to achieve desired management goals. Even so, our results suggest that alternative prey can reduce Largemouth Bass predation mortality on fingerlings immediately after stocking, which could influence Channel Catfish stocking approaches in some managed systems.

Do fishways stress fish? Assessment of physiological and hydraulic parameters of rainbow trout navigating a novel W-weir fishway

Experiments were performed in a novel pool & weir fishway to study the relationship between hydrodynamic and physiological parameters using rainbow trout (Oncorhynchus mykiss; mean TL = 15 cm). Fish were tested randomly using three fishway slopes (4, 7 and 10%) and three spacing ratios of W shaped weirs. Effect on fish hematology, immunology and stress were examined. Results showed that changing fishway hydraulic conditions altered fish stress levels. Increasing fishway slope and decreasing weir spacing, resulted in increased number of red blood cells and hematocrit, and decreased white blood cell count and serum lysosomes. In addition, levels of the most important stress indicator, cortisol, were elevated significantly compared to the control group, as slope, and consequently turbulence levels increased. Results showed that maximum turbulent kinetic energy (TKE) for a 10% fishway slope was increased to 0.22 m2/s2 while for a 4% slope and larger weir spacing was reduced to 0.05 m2/s2 which is the best condition for fish to rest in the pools created between the weirs. Observations on turbulence metrics showed that a weir spacing ratio of 6 offered the lowest gradients of energy changes. Furthermore, increasing the spacing ratio from 2 to 6 reduced cortisol levels and generally improved the physiological status of fish in the fishway. Considering turbulence levels at different depths of flow, the study concluded that physiological conditions for the passage of rainbow trout were best for a spacing ratio of 6 and a fishway slope of 4%. The evaluation of physiological metrics proved to be a vital and reliable process to integrate with hydrodynamics so fishway designs may be optimized to avoid stressing fish, and to enhance survival opportunities for migrating populations.

Toxic effects of selected trace elements contained in make-ups on female university students in Nigeria.

Arsenic (As), cadmium (Cd), lead (Pb), mercury (Hg), beryllium (Be), nickel (Ni), selenium (Se), and thallium (Tl) are reportedly notorious toxic contents of make-ups, with potential to cause cancer and chronic kidney disease, warranting investigation on their toxic effects. One hundred female university students were randomly selected as consistent users of make-ups for upward of 3years. The serum/urine levels of the 8 elements were regressed against the kidney functions (estimated glomerular rate, eGFR) of the subjects. At coefficient of - 0.009, As had insignificant (0.518) level. The coefficient for Cd was - .155 and insignificant (0.423). At coefficient of - 039, Pb level was insignificant (0.595). The coefficient, 0.061, for Hg was insignificant (0.462). At - 1.585, the coefficient of Be was insignificant (0.292). The coefficient for Ni, 1.384, was insignificant (0.354). At - .002, the coefficient of Se was insignificant (0.635). The coefficient, 0.039, for Tl was significant at 5% (0.015). This finding internally validated the mean serum Tl level, 201.4900 ± 20.63316μg/L, which was much higher than the normal level of < 2µg/L and within the toxic range of > 200µg/L. A policy is needed to address the use of make-ups containing Tl.

Efficacy and Temporal Capture Patterns of Bank Poles in the Kansas River: A Novel Sampling Tool for Catfish

AbstractSetlines and trotlines are useful tools for sampling catfish populations. These gears offer an alternative to sampling in habitats or conditions that are unsuitable for traditional sampling gears, and they may be capable of sampling a different subset of the population. However, little is known about their efficacy as catfish sampling gear. We developed a standardized method for deploying setlines in the form of bank poles and assessed the catch rate, species composition, and efficacy of bank poles in the Kansas River, Kansas. We also used Lindgren‐Pitman hook timers to investigate temporal patterns of capture, retention rates, and optimal soak duration. Bank poles (n = 897) were equipped with 6/0 circle hooks baited with Silver Carp Hypophthalmichthys molitrix cut bait and were deployed overnight during the summers of 2018 and 2019. Bank poles captured a total of seven fish species, with 97% of the species composition being catfishes (n = 258; mean TL = 688 ± 182.7 mm; range = 392–1,310 mm). Blue Catfish Ictalurus furcatus (45%) was the most commonly captured species, followed by Channel Catfish I. punctatus (37%) and Flathead Catfish Pylodictis olivaris (15%). The success rate for hooking and landing fish with bank poles was 29%. There was no difference between total catch rates from standard bank poles and those from bank poles equipped with hook timers. Higher catch rates were observed early in the set time for Channel and Flathead catfish, whereas a relatively steady catch rate was observed for Blue Catfish. Overall, 46% of catfish were caught within 3 h of gear deployment and 72% were caught within 5 h. We recommend adopting shortened soak durations (about 5 h) to prevent bait loss and to optimize fish retention. Our study provides an alternative sampling approach to increase the catch of large individuals and offers insight into the catch dynamics and interactions of passive angling gears.

Time to rethink trophic levels in aquaculture policy

AbstractAquaculture policy often promotes production of low‐trophic level species for sustainable industry growth. Yet, the application of the trophic level concept to aquaculture is complex, and its value for assessing sustainability is further complicated by continual reformulation of feeds. The majority of fed farmed fish and invertebrate species are produced using human‐made compound feeds that can differ markedly from the diet of the same species in the wild and continue to change in composition. Using data on aquaculture feeds, we show that technical advances have substantially decreased the mean effective trophic level of farmed species, such as salmon (mean TL = 3.48 to 2.42) and tilapia (2.32 to 2.06), from 1995 to 2015. As farmed species diverge in effective trophic level from their wild counterparts, they are coalescing at a similar effective trophic level due to standardisation of feeds. This pattern blurs the interpretation of trophic level in aquaculture because it can no longer be viewed as a trait of the farmed species, but rather is a dynamic feature of the production system. Guidance based on wild trophic position or historical resource use is therefore misleading. Effective aquaculture policy needs to avoid overly simplistic sustainability indicators such as trophic level. Instead, employing empirically derived metrics based on the specific farmed properties of species groups, management techniques and advances in feed formulation will be crucial for achieving truly sustainable options for farmed seafood.

Telomere Length in Idiopathic Recurrent Pregnancy Loss.

Telomere length is used as an indicator of biological aging. It is well known that one of the most remarkable risk factors of recurrent pregnancy losses is advanced maternal age. The objective of this study was to investigate the correlation between idiopathic recurrent pregnancy loss and telomere length. The study group included 40 women, while the control group consisted of 41 healthy women whose age and body mass index were matched. A venous blood sample was taken from all participants into EDTA tubes in the early follicular phase, and telomere length was measured through the qPCR technique. When the mean TL of the groups was compared, it was determined that TL was significantly shorter among the iRPL group (7763.89±924.58 base pair) compared to the control group (8398.84±1102.95 base pair) (p<0.006). Whereas FSH and E2 were higher in the iRPL group, TAFC was lower (p<0.001). When the correlation between telomere length and endocrine parameters was statistically tested in the iRPL group, a negative correlation was found between FSH and telomere length (r=-0.437; p<0.001). Shortened telomere length might play a role in the etiology of iRPL. We are of the opinion that patients with RPL should be screened for the presence of cardiovascular diseases and other chronic diseases, as is the case for POF.

Morphometric characteristics of Red Sokoto and Sahel goats in Maigatari Local Government Area of Jigawa State

The initial step involved in any animal genetic improvement program is to describe the morphometric traits considered. Therefore, a study was conducted in Maigatari Local Government Area of Jigawa State to determine some morphometric characteristics of Red Sokoto and Sahel goats. A total of 250 goats (187 Red Sokoto and 63 Sahel) of mixed sex and age were used for the study. The animals were sampled from Maigatari main livestock market. Data generated were subjected to simple descriptive, analysis of variance, Pearson's correlation analysis and stepwise linear regression. The coefficients of variation obtained for the parameters ranged from 8.96 % for wither height to 56.89 % for udder circumference. Red Sokoto had mean BW, BCS, BL, HG, WH, UL, UC, TL and TC of 20.58 kg, 3.20, 22.45 cm, 25.28 cm, 22.93 cm, 3.48 cm, 5.99 cm, 4.97 cm and 7.88 cm, respectively. The corresponding values for Sahel were 22.91 kg, 3.00, 23.58 cm, 25.07 cm, 24.55 cm, 4.14 cm, 7.06 cm, 4.75 cm and 7.52 cm. Sahel goats had significantly higher BL (P&lt;0.01) and WH (P&lt;0.001). Female goats were heavier than male and had longer body, wider chest and higher height at wither. Except TC, goats of 36 - 48 months had the highest for all the significantly affected traits (BW, BCS, BL, HG and WH; P&lt;0.001). The correlation coefficients observed among the morphometric traits were in general high, positive and significant, while the accuracy of the predictive equation when HG and in combination with BL were used to predict live weight was also high. This study indicated that breed had no effect on most body characters and that live weight can best be predicted using HG.

Trophic structure of apex fish communities in closed versus leaky lakes of arctic Alaska.

Despite low species diversity and primary production, trophic structure (e.g., top predator species, predator size) is surprisingly variable among Arctic lakes. We investigated trophic structure in lakes of arctic Alaska containing arctic char Salvelinus alpinus using stomach contents and stable isotope ratios in two geographically-close but hydrologically-distinct lake clusters to investigate how these fish may interact and compete for limited food resources. Aside from different lake connectivity patterns ('leaky' versus 'closed'), differing fish communities (up to five versus only two species) between lake clusters allowed us to test trophic hypotheses including: (1) arctic char are more piscivorous, and thereby grow larger and obtain higher trophic positions, in the presence of other fish species; and, (2) between arctic char size classes, resource polymorphism is more prominent, and thereby trophic niches are narrower and overlap less, in the absence of other predators. Regardless of lake cluster, we observed little direct evidence of arctic char consuming other fishes, but char were larger (mean TL = 468 vs 264mm) and trophic position was higher (mean TP = 4.0 vs 3.8 for large char) in lakes with other fishes. Further, char demonstrated less intraspecific overlap when other predators were present whereas niche overlap was up to 100% in closed, char only lakes. As hydrologic characteristics (e.g., lake connectivity, water temperatures) will change across the Arctic owing to climate change, our results provide insight regarding potential concomitant changes to fish interactions and increase our understanding of lake trophic structure to guide management and conservation goals.