The Tasmanian Whitebait, Lovettia seali (Johnston), and the Whitebait Fishery

1950 ◽  
Vol 1 (2) ◽  
pp. 155 ◽  
Author(s):  
M Blackburn

The biology of the aplochitonid Lovettia seali (Johnston), which comprises over 95 per cent. of the Tasmanian whitebait catch, has been studied. Over 78,000 fish from 95 samples were sexed and measured, and 1,200 were classified as to maturity, pigmentation stages, and the presence or absence of food in the stomach. Vertebra counts were made for 1,200 specimens, and there were other observations upon smaller amounts of material. There are marked resemblances to other salmonoids in most points of the biology. There is conspicuous sexual dimorphism. The fish are anadromous and at their ascent are all mature or almost so, and all of the same age (one year by otoliths). After spawning begins there is progressive discoloration and emaciation, followed almost invariably by death. About 0.001 per cent. of the stock consists of two-year fish. The eggs are large compared with the size of fish (extremes of standard length in the adult stock are 33 and 70 mm.) and the incubation period is about three weeks. The larvae drift downstream to the sea. Sex ratio is highly variable, but generally the males greatly outnumber the females. A northern and a southern population can be distinguished, the differences being in growth rate and pigmentation. Each population supports a separate fishery, which operates on the ascending shoals. The history of the fisheries is outlined. The southern fishery has never been important because the fish available at the principal fishing locality are excessively pigmented. More suitable fish could be taken by operating further downstream, where the fish are typically at an earlier stage of maturity. The northern fishery has been vigorously prosecuted and overfishing was probably the cause of the decline in abundance of stock in 1947 and 1948. If there was overfishing, it operated purely by excessive removal of reproducers. The order of the optimum catch is empirically identified and a programme for the management of the stock, aiming at its rehabilitation, is recommended.

2015 ◽  
Vol 65 (3-4) ◽  
pp. 311-320 ◽  
Author(s):  
João Fabrício Mota Rodrigues ◽  
José Roberto Feitosa Silva

Studies focusing on the natural history of species are essential for developing effective conservation measures and evaluating ecological hypotheses. To this end, we describe natural history data of the Cotinga River toadhead turtle, Phrynops tuberosus, in the Banabuiú River in Ceará, Brazil, and evaluated sexual dimorphism, epibionts, and mutilation effects. We hand-captured 134 individuals by snorkeling, over a period of one year, resulting in the capture of 94 males, 24 females, and 16 juveniles. Females had larger head width and body mass than males, while males had longer tail length. One quarter of the turtles captured had some sort of injury or deformation, most common injuries being missing claws, mutilations, and shell deformations. We found no difference in body condition index between mutilated and non-mutilated animals. Mollusks, insects, and leeches were found as epibionts on P. tuberosus and most of the captured turtles had extensive algal cover. Future studies should focus on understanding the effect of mutilations on animal fitness and reproductive success.


2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Emmanuel Manangkalangi ◽  
Simon P.O. Leatemia ◽  
Luky Sembel ◽  
Paskalina T. Lefaan ◽  
Ridwan Sala ◽  
...  

ABSTRACTArfak rainbow fish, Melanotaenia arfakensis is an endemic fish on several river systems in the northeastern part of the Vogelkop peninsula. This study aims to describe the growth, age at first maturity, and sexual dimorphism of this endemic fish on the Nimbai Stream and the Aimasi Stream, the Prafi River system. The fish were caught using handnet, then were measured their standard length and individual weight. Data were analyzed to estimated growth patterns, von Bertalanffy's growth rate, age at first maturity and sexual dimorphism characteristics. The results showed that male growth patterns varied, with a tendency of the increase in body length faster than that of body weight (negative allometric patterns) with b values ranging from 2.886 to 3.132. On the other hand, the female individuals had positive allometric patterns (b values ranged from 3.062 to 3.378). The growth rate (K) of male body length was faster (0.165-0.174) than that of female individuals (0.159-0.163). Male individuals reached the first maturity condition earlier (at age of 1.83-2.18 years) than female individuals (at age of 2.49-2.64 years). Sexual characteristics between the sexes are related to body height starting to appear when fish are of a standard length of larger than 18.22 mm or when male fish begin to approach the time of the first sexual maturity. Understanding of growth, age, and the characteristics of the sexual dimorphism of endemic fish has an important meaning in monitoring population conditions and for conservation efforts in their natural habitat.


Author(s):  
José G. Pajuelo ◽  
José M. Lorenzo

The reproductive biology of 1318 sand sole, Pegusa lascaris, was investigated. This species is a gonochoristic species with no evidence of sexual dimorphism. The overall sex-ratio was 1 male to 0.92 females. Females predominate in the larger size intervals, with a significant difference in mean standard length and range between sexes. Size at first maturity for males and females is attained at 17.2 and 17.7 cm standard length, respectively. Vitellogenesis does not begin synchronously for all females, as a consequence the spawning season appears to be continuous. In each female spawning takes place in two batches which are spawned mainly in spring and autumn, indicating that fish are serial synchronous spawners.


Author(s):  
Carlos Litulo

The population biology and reproduction of the hermit crab Clibanarius longitarsus were studied with emphasis on size structure, sex ratio, breeding season and fecundity. Specimens were sampled monthly over a period of one year (January–December 2003) at Costa do Sol mangrove, Maputo Bay, southern Mozambique. A total of 597 individuals was obtained of which 202 were males, 192 non-ovigerous females and 203 ovigerous females. Annual size–frequency distributions were polymodal for males and bimodal for non-ovigerous and ovigerous females, respectively. Sexual dimorphism was recorded by the larger average size attained by males in relation to females. Sex ratio was female-biased during most months of the study. Clibanarius longitarsus showed a higher reproductive activity with two major peaks (March and October). Juvenile recruitment was continuous throughout the study period. Clutch size was positively associated with female size. The high number of ovigerous females as obtained in the present population may evidence a higher reproductive activity displayed by C. longitarsus at Costa do Sol mangrove.


Author(s):  
L. Fernández ◽  
E. González-Gurriarán ◽  
J. Freire

The population biology of the crab Liocarcinus depurator was studied for one year in the mussel raft culture areas of the Ria de Arousa. The density and biomass of this species is much higher in the raft areas, especially in the outer part of the ria, than in the central channel area. Maximum abundance occurred during the winter months (up to 8-80 g wet weight m and 0-44 individuals m.Maturity size in females was set at 28-30 mm carapace width, (based on ovigerous females) and is attained in the first year of life. The ovigerous females were most abundant in January (approximately 70% of the mature females), but another less important maximum value was observed in May, attributable to a second spawning. Modifications in the sex ratio from 1:1 affected individuals larger than the maturity size during the season when there was a greater number of ovigerous females present. Data on sex ratio and breeding cycle indicate that ovigerous females move towards the raft areas located in the outer part of the ria. Trawl recruitment took place in the stations located in the outer Ria, and mainly in August-September, although it continued to a lesser extent in autumn.The Von Bertalanffy growth function was fitted to both sexes in the two outer stations. Growth rate was higher in males than in females, while variability between stations was less important. However the growth rate and reproductive output of L. depurator in the Ria de Arousa was higher than in populations from other geographical areas, possibly because of the availability of food from the rafts and or the oceanographic conditions in the ria.


VASA ◽  
2010 ◽  
Vol 39 (2) ◽  
pp. 169-174 ◽  
Author(s):  
Reich-Schupke ◽  
Weyer ◽  
Altmeyer ◽  
Stücker

Background: Although foam sclerotherapy of varicose tributaries is common in daily practice, scientific evidence for the optimal sclerosant-concentration and session-frequency is still low. This study aimed to increase the knowledge on foam sclerotherapy of varicose tributaries and to evaluate the efficacy and safety of foam sclerotherapy with 0.5 % polidocanol in tributaries with 3-6 mm in diameter. Patients and methods: Analysis of 110 legs in 76 patients. Injections were given every second or third day. A maximum of 1 injection / leg and a volume of 2ml / injection were administered per session. Controls were performed approximately 6 months and 12 months after the start of therapy. Results: 110 legs (CEAP C2-C4) were followed up for a period of 14.2 ± 4.2 months. Reflux was eliminated after 3.4 ± 2.7 injections per leg. Insufficient tributaries were detected in 23.2 % after 6.2 ± 0.9 months and in 48.2 % after 14.2 ± 4.2 months, respectively. Only 30.9 % (34 / 110) of the legs required additional therapy. In 6.4 % vein surgery was performed, in 24.5 % similar sclerotherapy was repeated. Significantly fewer sclerotherapy-sessions were required compared to the initial treatment (mean: 2.3 ± 1.4, p = 0.0054). During the whole study period thrombophlebitis (8.2 %), hyperpigmentation (14.5 %), induration in the treated region (9.1 %), pain in the treated leg (7.3 %) and migraine (0.9 %) occurred. One patient with a history of thrombosis developed thrombosis of a muscle vein (0.9 %). After one year there were just hyperpigmentation (8.2 %) and induration (1.8 %) left. No severe adverse effect occurred. Conclusions: Foam sclerotherapy with injections of 0.5 % polidocanol every 2nd or 3rd day, is a safe procedure for varicose tributaries. The evaluation of efficacy is difficult, as it can hardly be said whether the detected tributaries in the controls are recurrent veins or have recently developed in the follow-up period. The low number of retreated legs indicates a high efficacy and satisfaction of the patients.


Author(s):  
Jed Z. Buchwald ◽  
Mordechai Feingold

Isaac Newton’s Chronology of Ancient Kingdoms Amended, published in 1728, one year after the great man’s death, unleashed a storm of controversy. And for good reason. The book presents a drastically revised timeline for ancient civilizations, contracting Greek history by five hundred years and Egypt’s by a millennium. This book tells the story of how one of the most celebrated figures in the history of mathematics, optics, and mechanics came to apply his unique ways of thinking to problems of history, theology, and mythology, and of how his radical ideas produced an uproar that reverberated in Europe’s learned circles throughout the eighteenth century and beyond. The book reveals the manner in which Newton strove for nearly half a century to rectify universal history by reading ancient texts through the lens of astronomy, and to create a tight theoretical system for interpreting the evolution of civilization on the basis of population dynamics. It was during Newton’s earliest years at Cambridge that he developed the core of his singular method for generating and working with trustworthy knowledge, which he applied to his study of the past with the same rigor he brought to his work in physics and mathematics. Drawing extensively on Newton’s unpublished papers and a host of other primary sources, the book reconciles Isaac Newton the rational scientist with Newton the natural philosopher, alchemist, theologian, and chronologist of ancient history.


1970 ◽  
Vol 11 (1) ◽  
Author(s):  
A. Bista ◽  
G. B. Khattri ◽  
B. D. Acharya ◽  
S. C. Srivastava

To find out the ability of Orobanche seeds to germinate immediately after seed set, seeds were germinated periodically at an interval of three months for one year in GR24. Some Orobanche seeds were capable of germination immediately after seed set but most required about nine months as after ripening or incubation period to be able to germinate. The phenomenon of after ripening in Orobanche seeds could be taken as an ecological measure to dormant over following unfavorable wet summer season. The growth hormone studies on Orobanche seed germination have shown that GA3 at a concentration of 100 ppm substantially enhanced seed germination when applied during pre-conditioning period. NAA showed some stimulatory effect at 0.5 - 1.0 ppm when applied during post-conditioning period but the hormone if applied during pre-conditioning period inhibited the germination. Kinetin failed to stimulate the germination at all the concentrations tested. Key words: Germination, root-parasite, hormone. Ecoprint Vol.11(1) 2004.


2019 ◽  
Vol 16 (3) ◽  
pp. 250-257 ◽  
Author(s):  
Jiann-Der Lee ◽  
Ya-Han Hu ◽  
Meng Lee ◽  
Yen-Chu Huang ◽  
Ya-Wen Kuo ◽  
...  

Background and Purpose: Recurrent ischemic strokes increase the risk of disability and mortality. The role of conventional risk factors in recurrent strokes may change due to increased awareness of prevention strategies. The aim of this study was to explore the potential risk factors besides conventional ones which may help to affect the advances in future preventive concepts associated with one-year stroke recurrence (OSR). Methods: We analyzed 6,632 adult patients with ischemic stroke. Differences in clinical characteristics between patients with and without OSR were analyzed using multivariate logistic regression and classification and regression tree (CART) analyses. Results: Among the study population, 525 patients (7.9%) had OSR. Multivariate logistic regression analysis revealed that male sex (OR 1.243, 95% CI 1.025 – 1.506), age (OR 1.015, 95% CI 1.007 - 1.023), and a prior history of ischemic stroke (OR 1.331, 95% CI 1.096 – 1.615) were major factors associated with OSR. CART analysis further identified age and a prior history of ischemic stroke were important factors for OSR when classified the patients into three subgroups (with risks of OSR of 8.8%, 3.8%, and 12.5% for patients aged > 57.5 years, ≤ 57.5 years/with no prior history of ischemic stroke, and ≤ 57.5 years/with a prior history of ischemic stroke, respectively). Conclusions: Male sex, age, and a prior history of ischemic stroke could increase the risk of OSR by multivariate logistic regression analysis, and CART analysis further demonstrated that patients with a younger age (≤ 57.5 years) and a prior history of ischemic stroke had the highest risk of OSR.


Author(s):  
Shinwan Kany ◽  
Johannes Brachmann ◽  
Thorsten Lewalter ◽  
Ibrahim Akin ◽  
Horst Sievert ◽  
...  

Abstract Background Non-paroxysmal (NPAF) forms of atrial fibrillation (AF) have been reported to be associated with an increased risk for systemic embolism or death. Methods Comparison of procedural details and long-term outcomes in patients (pts) with paroxysmal AF (PAF) against controls with NPAF in the prospective, multicentre observational registry of patients undergoing LAAC (LAARGE). Results A total of 638 pts (PAF 274 pts, NPAF 364 pts) were enrolled. In both groups, a history of PVI was rare (4.0% vs 1.6%, p = 0.066). The total CHA2DS2-VASc score was lower in the PAF group (4.4 ± 1.5 vs 4.6 ± 1.5, p = 0.033), while HAS-BLED score (3.8 ± 1.1 vs 3.9 ± 1.1, p = 0.40) was comparable. The rate of successful implantation was equally high (97.4% vs 97.8%, p = 0.77). In the three-month echo follow-up, LA thrombi (2.1% vs 7.3%, p = 0.12) and peridevice leak > 5 mm (0.0% vs 7.1%, p = 0.53) were numerically higher in the NPAF group. Overall, in-hospital complications occurred in 15.0% of the PAF cohort and 10.7% of the NPAF cohort (p = 0.12). In the one-year follow-up, unadjusted mortality (8.4% vs 14.0%, p = 0.039) and combined outcome of death, stroke and systemic embolism (8.8% vs 15.1%, p = 0.022) were significantly higher in the NPAF cohort. After adjusting for CHA2DS2-VASc and previous bleeding, NPAF was associated with increased death/stroke/systemic embolism (HR 1.67, 95% CI 1.02–2.72, p = 0.041). Conclusion Atrial fibrillation type did not impair periprocedural safety or in-hospital MACE patients undergoing LAAC. However, after one year, NPAF was associated with higher mortality. Graphic abstract


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