Reproductive characteristics and per-recruit analyses of blue warehou (Seriolella brama): implications for the South East Fishery of Australia

2001 ◽  
Vol 52 (4) ◽  
pp. 575 ◽  
Author(s):  
Ian A. Knuckey ◽  
K. P. Sivakumaran

Monthly samples of commercial catches of S. brama were collected between May 1996 and December 1997 in three regions of the fishery:off the east coast of Victoria; eastern Tasmania; and western Bass Strait. Sex ratio, gonadosomatic index, macroscopic and histological development, size at maturity and fecundity were estimated and combined with data on growth and mortality to perform per-recruit analyses. The main spawning period was during winter–spring and there was evidence of spawning in each of the three regions. Blue warehou reach maturity at 30–40 cm fork length. They have a determinate annual fecundity and spawn around three batches of eggs during a season. Eggs-per-recruit analyses revealed maximum egg production at ~40 cm (4–5 years) in an unfished population. Gill-net fishing, which targets fish >45 cm, was less likely to affect the relative eggs-per-recruit in a population than trawl fishing, which catches a wider range of smaller fish. These results are discussed in light of the current management arrangements in the fishery and will be used in models to assess the effect of fishing on the long-term sustainability of the blue warehou.

2003 ◽  
Vol 54 (4) ◽  
pp. 315 ◽  
Author(s):  
Jock Young ◽  
Anita Drake ◽  
Michael Brickhill ◽  
Jessica Farley ◽  
Thor Carter

The reproductive ecology of broadbill swordfish, Xiphias gladius, was evaluated based on 1437 fish (size range 50–300 cm orbital fork length [OFL]) caught in the domestic longline fisheries off eastern Australia and New Zealand between May 1999 and March 2001. Reproductive activity was assessed using histology, a gonadosomatic index, and maximum oocyte size. Males were significantly smaller than females and represented less than one third of the sampled fish. Sex ratio differed significantly with respect to fish size and time of year. Females began maturing at 150-cm OFL and spawned from September to March, with the greatest activity from December to February. Males matured at 90-cm OFL; ripe males were found from January to March, but also in May and October, suggesting an extended reproductive period. During the spawning period the proportion of spawning to inactive mature sized females was significantly higher in waters west of longitude 158°E than in waters to the east. Further to the east, samples taken from the New Zealand fishery showed no actively spawning fish during the main spawning period. Females were increasingly reproductively active as water temperature increased beyond 24°C and sea surface chlorophyll a decreased below 0.2 μg L–1. Batch fecundity was linearly related to fish length with a mean batch fecundity of 1.66 million oocytes for females ranging in size from 173- to 232-cm OFL. The presence of hydrated oocytes and post-ovulatory follicles (POFs) in the same ovaries indicated multiple spawnings. Depending on the time taken for POFs to degrade, these may have been daily at the height of the spawning season.


2016 ◽  
Vol 63 (4) ◽  
Author(s):  
K. M. Rajesh ◽  
Prathibha Rohit ◽  
E. M. Abdussamad

Fishery, diet composition and reproductive biology of the dolphinfish Coryphaena hippurus (Linnaeus, 1758) landed along Karnataka Coast during 2013-15 were studied. The estimated average landing of the species in India during the study period was 7975 t of which Karnataka contributed 2.73% (218 t). The fish is mainly exploited by gillnet and also by troll lines operated from trawlers. A few stray specimens were also landed by purse seines. The fork length (FL) was in the range of 32-128 cm and fishes in the length range (FL) of 55-90 cm dominated the catch, contributing 79.8% of the total landings. The most dominant prey item, in terms of occurrence (70.57%) and weight (83.18%) were finfishes followed by cephalopods (19.62% by occurrence and 13.66% by weight) and crustaceans (7.01% occurrence and 1.32% by weight). The index of relative importance (IRI ) values were 85.3, 13.39 and 0.68% respectively for fish, cephalopods and crustaceans respectively. Sex ratio (1:2.05) indicated dominance of females in the fishery. Presence of mature and spent specimens throughout the year suggests that the species spawns all through the year. Peak spawning period was from June to September. This coincided with gradual increase in gonadosomatic index (GSI) values ahead of May which reached a peak during August-September.


2020 ◽  
Vol 71 (6) ◽  
pp. 653 ◽  
Author(s):  
John Stewart ◽  
Alice Pidd ◽  
Ashley M. Fowler ◽  
Wayne Sumpton

Understanding the spatial ecology of exploited fish stocks is key to their sustainable management. Here we used a long-term cooperative tag and recapture dataset that encompassed the entire distribution of the stock to examine patterns of movement and growth of Chrysophrys auratus (Sparidae) along eastern Australia. More than 24000 individuals were tagged, with 2117 being recaptured with information suitable for analysis of movements and 1440 with information suitable for analysis of growth rates. Individuals ranged in size between 120- and 620-mm fork length at tagging and were at liberty for up to 5.9 years before being recaptured. Results indicated population characteristics of partial migration, whereby the majority (~71%) of fish did not move any detectable distance and a small proportion (~4%) moved between 100 and 1000km. Specific growth rates were significantly affected by the latitude at tagging, with higher growth rates at lower (more northern) latitudes. Our findings suggest that Australian east-coast C. auratus are mainly resident on a subdecadal time scale and at reasonably small spatial scales. When considered with information on latitudinal variation in growth and reproductive biology, localised recruitment and a history of localised fishery declines, assessment and management at local scales may be appropriate.


2019 ◽  
Vol 77 (2) ◽  
pp. 680-691 ◽  
Author(s):  
Na Wang ◽  
Anthony J Courtney ◽  
Matthew J Campbell ◽  
Wen-Hsi Yang

Abstract This article estimated the weight of annual discards in the Queensland east coast otter trawl fishery. Discards data were analysed using three generalized linear mixed models to derive adjusted discard rates, expressed as kg per retained catch, kg per boat day, and kg per area swept by trawls, respectively. Model explanatory terms included trawl fishing sector, presence/absence of bycatch reduction devices (BRDs), lunar phase, and whether the data were obtained from commercial vessels during their normal fishing activities or during research charters. Adjusted discard rates were then used to derive three estimates of annual discards and the average used to examine a long-term discard trends from 1988 to 2014. Total discards declined significantly from a peak of approximately 67 000 t in 1997 to approximately 21 000 t from 2011 to 2014, largely due to a decline in fishing effort, and to a lesser degree, the effects of BRDs that were mandated in the fishery in the early 2000s.


2018 ◽  
Vol 6 (5) ◽  
pp. 114-127
Author(s):  
Ebram Luc Gervais ◽  
Soumaïla SYLLA ◽  
Tizié Thierry ZAN-BI ◽  
Boua Célestin ATSE

The reproduction of Liza falcipinnis were investigated in both lagoons (Ebrié and Grand-Lahou) from January 2006 to december 2007. 2162 specimens were examined (914 and 1248 respectively in Ebrié and Grand-Lahou lagoons). Fork length was taken to the nearest 1 mm, and total body weight (TW) and eviscerated body weight (EW) to the nearest 0.1 g. The gonads and the liver were then established removed, weighted to the nearest 0.001g. The reproduced period of Liza falcipinnis was established by analysing the temporal evolution of the frequency of the maturity stages and the monthly variations in the gonadosomatic index (GSI), the hepatosomatic index (HIS) and the condition factor (K). Sex ratio was established taking into account the sex determinations. The size at which 50 % of the specimens became mature (FL50) was estimated. The sex ratio (1:1.24) and (1:1.40) observed respectively in Ebrié and Grand-Lahou lagoons were in favour of females. The first sexual maturity size was 21.0 cm (FL) for males and 27.9 cm (FL) for females in Ebrié lagoon and 24.7 cm (FL) for males and 27.9 cm (FL) for females in Grand-Lahou lagoon. Liza falcipinnis spawns in lagoon and the spawning period ranged from December to April.


2018 ◽  
Vol 69 (2) ◽  
pp. 300
Author(s):  
Simone Marques ◽  
Beatrice P. Ferreira

This study reports on the pattern of sexual development and demography of Epinephelus adscensionis sampled on the north-east coast of Brazil. The species is a protogynous hermaphrodite, with males (26–44-cm total length, TL) transitioning from mature females (20–33cm TL). This species presented multiple spawning, with peaks in the gonadosomatic index indicating that the spawning period of the rock hind occurred along 3 months per year, where for 2008 was between August and October, and for 2009 was between July and September. Age was determined from otoliths and periodicity was validated from captive fish treated with tetracycline. The resulting von Bertalanffy growth parameters were as follows: theoretical maximum length (L∞) 34.82cm TL, growth coefficient (k) 0.26 and theoretical age at L=0 (t0) 0.86years. The size and age at sexual maturity for females were 20cm TL and 4 years. The total rate of mortality was 0.28year–1. Older fish were males and had a maximum longevity of 15 years. This species is an important resource for local communities, but is also currently caught by trap fisheries, which have been expanding in recent decades in response to demands of export markets. Lack of monitoring and management of these and other reef fisheries in north-east Brazil makes fishing sustainability uncertain.


1988 ◽  
Vol 39 (6) ◽  
pp. 729 ◽  
Author(s):  
AJ Courtney ◽  
MCL Dredge

In the coastal region of central Queensland female red-spot king prawns, P. longistylus, and the western or blue-leg king prawns, P. latisulcatus, had high mean ovary weights and high proportions of advanced ovary development during the winter months of July and August of 1985 and 1986. On the basis of insemination, both species began copulating at the size of 26-27 mm CL, but P. longistylus matured and spawned at a smaller size than P. latisulcatus. Abundance of P. longistylus was generally three to four times greater than that of P. latisulcatus but the latter was subject to greater variation in abundance. Low mean ovary weight and low proportions of females with advanced ovaries were associated with the maximum mean bottom sea-water temperature (28.5�C) for both species. Population fecundity indices indicated that peaks in yolk or egg production (a) displayed a similar pattern for both species, (b) varied in timing from year to year for both species and (c) were strongly influenced by abundance. Generally, sample estimates of abundance and commercial catch rates (CPUE) showed similar trends. Differences between the two may have been due to changes in targeted commercial effort in this multi-species fishery.


2021 ◽  
Vol 108 (Supplement_7) ◽  
Author(s):  
Harish Peri ◽  
Rafique Umer Harvitkar

Abstract Introduction Open injuries have a potential for serious bacterial wound infections and may lead to long term disabilities, chronic wound or bone infection, and even death. This QI study was undertaken to ring in changes to the current management protocol and align them as per WHO guidelines. Method Implementing changes through a Plan-Do-Study-Act (PDSA) cycle post an initial clinical audit among 38 patients of the organization. Re-audits were done to measure the outcome against the standard and establish a new protocol. Results Initial audit showed only a dismal 37% (n = 14) of patients being managed as per WHO protocol. Patient satisfaction percentage (as measured by a questionnaire) was also low with only 54% of patients satisfied with the treatment. Significant variations were noted post implementation of changes after the first PDSA cycle where >90% (n = 35) of patients reported that they noticed better wound healing, transition to optimal performance and were satisfied with treatment outcomes. Conclusions Timely wound dressings, appropriate antibiotic prophylaxis and increased patient’s awareness on wound hygiene through means of regular educational sessions and updated management protocols have led to healthier patients, lesser long term disabilities and happy patients.


2015 ◽  
Vol 42 (5) ◽  
pp. 477-499
Author(s):  
Michael John Paton

The 2011 tsunami had a devastating effect on the east coast of Japan. Particularly poignant were the century-old markers on hillsides warning against building anywhere below. Nevertheless, such wisdom from traditional knowledge was disregarded because of the perceived invulnerability of the modern. This paper attempts to garner such traditional empirical knowledge regarding the siting of towns and cities by considering the Chinese art/science of fengshui (wind and water) or dili (principles of the earth), the original purpose of which was to site human habitation in the most favourable places for long term survival. This knowledge is then used to consider the placement of cities created by modernity, those founded on and flourishing through the advent of globalisation, such as Hong Kong, Shanghai, St Petersburg, and Sydney.


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