Factors affecting the catch rates and relative abundance of sea snakes in the by-catch of trawlers targeting tiger and endeavour prawns on the northern Australian continental shelf

2000 ◽  
Vol 51 (2) ◽  
pp. 155 ◽  
Author(s):  
T. M. Ward
Keyword(s):  
Continental Shelf ◽  
Relative Abundance ◽  
Sampling Effort ◽  
Sea Snake ◽  
Factors Affecting ◽  
Sea Snakes ◽  
The Status ◽  
By Catch ◽  
Catch Rates ◽  
Northern Prawn Fishery

A total of 4378 sea snakes (14 species; 5 unidentified specimens) were collected from 21 082 h of sampling effort by trawlers of the Northern Prawn Fishery. Most species (12) were collected from the southern Gulf of Carpentaria. Hydrophis elegans and Disteira major were caught frequently in all areas. The catch rates of H. elegans and Lapemis hardwickii were highest in the eastern gulf and in depths of 31–40 and <20 m respectively. Hydrophis elegans represented >27% of specimens from most areas. Other species that represented ≥20% of specimens from one or more areas were: L. hardwickii, H. ornatus, D. major and Aipysurus eydouxii. Catch rates of all species of snakes combined did not differ significantly between 1984–86 and 1989–90, and were moderately high around Groote Eylandt where the fishery is centred. Most by-catch species occur in areas that are not subjected to extensive trawling, and there are no data to suggest that this fishery seriously threatens any population of sea snake. However, sea snakes may be more vulnerable to trawler-induced effects than most other by-catch species, and formal assessment of the status of populations is needed.

Sea snake by-catch of prawn trawlers on the northern Australian continental shelf

1996 ◽  
Vol 47 (4) ◽  
pp. 631 ◽  
Author(s):  
TM Ward
Keyword(s):  
Data Collection ◽  
Continental Shelf ◽  
Total Catch ◽  
Sea Snake ◽  
Sea Snakes ◽  
Cape York ◽  
By Catch ◽  
Penaeus Merguiensis ◽  
Northern Prawn Fishery

This paper describes and compares the sea snakes caught by vessels that target tiger prawns and endeavour prawns or that target the banana prawns Penaeus merguiensis and P. indicus. In 1989-90, 5203 sea snakes (14 species; 7 unidentified specimens) were purchased from fishers who trawled between Koolan Island and Cape York and participated in a dedicated carcass-tagging and data-collection programme. Hydrophines (11 species) represented 86.7% of the total catch. Aipysurines (3 species) represented 15.0% of specimens from vessels that targeted tiger prawns or endeavour prawns, but only 1.1% of specimens from vessels that targeted the banana prawns P. merguiensis and P. indicus. Prawn trawlers that operated between Koolan Island and Cape York during 1990 caught approximately 81 080 (� 13 670) sea snakes. Vessels that targeted tiger/endeavour prawns, P. merguiensis and P. indicus caught approximately 69260 (� 8750), 7200 (� 3250) and 4620 (� 1120) sea snakes respectively. The results emphasize the advantages of interactions between fishers and scientists and the need to assess separately the impacts of the three fisheries that constitute the northern prawn fishery.

Sea snake by-catch of fish trawlers on the northern Australian continental shelf

1996 ◽  
Vol 47 (4) ◽  
pp. 625 ◽  
Author(s):  
TM Ward
Keyword(s):  
Continental Shelf ◽  
Absolute Abundance ◽  
Sea Snake ◽  
North West ◽  
The North ◽  
Sea Snakes ◽  
Exponential Decline ◽  
Arafura Sea ◽  
By Catch ◽  
Trawl Surveys

During 1986-90, 206 sea snakes were collected from Taiwanese pair-trawlers (North West Shelf, 1986-87), Thai stern-trawlers (Arafura Sea, 1986-87), RV Soela (North West Shelf, 1986) and RV Clipper Bird (Timor and Arafura Seas, 1990). Taiwanese (58 specimens; 294.8 h trawled) and Thai (71 specimens; 1244 h trawled) vessels trawled in 50-75 m and caught 10 and 7 species respectively. The Soela (41 specimens; 72.5 h trawled) and Clipper Bird (36 specimens; 103 h trawled) operated in depths of 19-198 m and each caught 12 species. Hydrophines (10 species plus one specimen from an undescribed taxon) represented 68.4% of the specimens. Aipysurines (6 species) were more common in samples from the North West Shelf (46.2% of taxa, 56.6% of specimens) than from the Timor and Arafura Seas (28.6% of taxa, 11.2% of specimens). Taiwanese boats on the North West Shelf (1980-90) and Thai boats in the Arafura Sea (1985-90) were estimated to have caught 49000 (� 5600) and 10000 (� 1250) sea snakes respectively. Trawl surveys (e.g. Soela and Clipper Bird) may be unsuitable for monitoring sea snakes, because approximately 25 surveys would be needed to detect a 20% exponential decline in absolute abundance.

Reducing impacts of trawling on protected sea snakes: by-catch reduction devices improve escapement and survival

2009 ◽  
Vol 60 (8) ◽  
pp. 824 ◽  
Author(s):  
David A. Milton ◽  
Gary C. Fry ◽  
Quinton Dell
Keyword(s):  
Crew Member ◽  
Western Pacific ◽  
Small Fish ◽  
Separate Study ◽  
Sea Snake ◽  
Fishing Season ◽  
Sea Snakes ◽  
Paired Control ◽  
By Catch ◽  
Northern Prawn Fishery

Sea snakes (Hydrophidae) are by-catch of prawn trawling throughout the tropical Indo-western Pacific. We tested the effectiveness of three by-catch reduction device (BRD) types set at different distances from the codend in Australia’s Northern Prawn Fishery (NPF). Trained crew-member observers compared the numbers of sea snakes caught in paired Control and Treatment nets in 1365 trawls. Catches of sea snakes were reduced by 43% on those vessels where a Fisheye BRD was positioned less than 70 meshes from the codend. A separate study with a scientific observer undertook trials with a ‘popeye’ Fishbox BRD. This BRD reduced sea snake catch by 85% and small fish by-catch by 48%. Catches of target prawn were similar for all nets in both studies (difference <2%). Adoption of the more effective BRDs (‘popeye’ Fishbox or Fisheye BRDs) by the NPF and locating them within 70 meshes of the codend can potentially reduce sea snake catch and thus their mortality from ~7000 in the 2007 fishing season to as few as 1500 snakes. Our study shows that the use of BRDs in tropical coastal demersal fisheries and positioning them closer to the codend will greatly reduce the catch of vulnerable sea snakes.

Hydrophis donaldi (Elapidae, Hydrophiinae), a highly distinctive new species of sea snake from northern Australia

Zootaxa ◽  
2012 ◽  
Vol 3201 (1) ◽  
pp. 45 ◽  
Author(s):  
KANISHKA D.B. UKUWELA ◽  
KATE L. SANDERS ◽  
BRYAN G. FRY
Keyword(s):  
New Species ◽  
Habitat Preferences ◽  
The Body ◽  
Colour Pattern ◽  
Northern Australia ◽  
Nucleotide Substitutions ◽  
Sea Snake ◽  
Sea Snakes ◽  
Morphological Diagnosis ◽  
By Catch

A new species of viviparous sea snake, Hydrophis donaldi sp. nov. (Hydrophiinae), is described from the Gulf of Carpen-taria, northern Australia. Molecular analyses reveal this species as a deeply divergent lineage within the Hydrophis sub-group, and separate it from all other sampled taxa by fixed nucleotide substitutions at three independent mitochondrial andnuclear loci. The new species is assigned to Hydrophis based on the current morphological diagnosis of this large but pa-raphyletic genus, and is distinguished from all other Hydrophis species and closely allied genera by a combination of mor-phological characters relating to scalation, colour pattern and osteology. Using current keys for sea snakes, H. donaldi sp.nov. might be mistaken for H. coggeri, H. sibauensis or H. torquatus diadema but it is readily distinguished from thesespecies by a higher number of bands on the body and tail, lower ventral count, strongly spinous body scales, and a wider,more rounded head. Sea snakes have been sampled intensively in the Gulf of Carpentaria due to their vulnerability to by-catch in the region’s commercial prawn-trawl fisheries. That this highly distinctive new species has evaded discovery inthe region until now is surprising, but might be explained by its habitat preferences. All known specimens of H. donaldi sp. nov. were found in estuarine habitats that are relatively poorly surveyed and are not targeted by commercial fisheries.

Age structures and reproductive patterns of two species of sea snake, Lapemis hardwickii Grey (1836) and Hydrophis elegans (Grey 1842), incidentally captured by prawn trawlers in northern Australia

2001 ◽  
Vol 52 (2) ◽  
pp. 193 ◽  
Author(s):  
T. M. Ward
Keyword(s):  
Sexual Maturity ◽  
Ecological Effects ◽  
Northern Australia ◽  
Sea Snake ◽  
Reproductive Patterns ◽  
Sea Snakes ◽  
By Catch ◽  
Reproductive Cycles ◽  
Age Structures

Lapemis hardwickiiand Hydrophis elegans caught by prawn trawlers reach at least 6.7 and 8.9 years of age respectively.Most L.hardwickii sampled were 2—4 years of age,and most H.elegans were 3—5 years of age. Female L.hardwickii and H.elegans appear to reach sexual maturity after 2 years and minimum snout—vent lengths of approximately 76 and 120 cm respectively.The reproductive cycles of L.hardwickii and H.elegans are similar:mating occurs between early May and the end of July;ovulation during August —September;and gestation during September—December and September—February respectively.L.hardwickii and H.elegans produce approximately 8.5 and 12.7 offspring per clutch respectively.However,female L.hardwickii breed annually whereas female H.elegans only breed every 2—3 years.The mean annual reproductive outputs of L. hardwickii (8.4 offspring per year)and H.elegans (7.5)are thus similar. Sea snakes appear to be less fecund and more susceptible to trawler-induced effects than most by-catch taxa,and should be a focus of future strategies to ameliorate the ecological effects of prawn trawling in northern Australia.

scholarly journals Interpreting catch per unit effort data to assess the status of individual stocks and communities

2006 ◽  
Vol 63 (8) ◽  
pp. 1373-1385 ◽  
Author(s):  
Mark N. Maunder ◽  
John R. Sibert ◽  
Alain Fonteneau ◽  
John Hampton ◽  
Pierre Kleiber ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Stock Assessment ◽  
Limited Information ◽  
Catch Per Unit Effort ◽  
Fish Stocks ◽  
Unit Effort ◽  
Strategy Evaluation ◽  
The Status ◽  
Catch Rates ◽  
Management Advice

AbstractDespite being one of the most common pieces of information used in assessing the status of fish stocks, relative abundance indices based on catch per unit effort (cpue) data are notoriously problematic. Raw cpue is seldom proportional to abundance over a whole exploitation history and an entire geographic range, because numerous factors affect catch rates. One of the most commonly applied fisheries analyses is standardization of cpue data to remove the effect of factors that bias cpue as an index of abundance. Even if cpue is standardized appropriately, the resulting index of relative abundance, in isolation, provides limited information for management advice or about the effect of fishing. In addition, cpue data generally cannot provide information needed to assess and manage communities or ecosystems. We discuss some of the problems associated with the use of cpue data and some methods to assess and provide management advice about fish populations that can help overcome these problems, including integrated stock assessment models, management strategy evaluation, and adaptive management. We also discuss the inappropriateness of using cpue data to evaluate the status of communities. We use tuna stocks in the Pacific Ocean as examples.

The reproductive biology and diet of sea snake bycatch of prawn trawling in northern Australia: characteristics important for assessing the impacts on populations

2001 ◽  
Vol 7 (1) ◽  
pp. 55 ◽  
Author(s):  
G. C. Fry ◽  
D. A. Milton ◽  
T. J. Wassenberg
Keyword(s):  
Benthic Fish ◽  
Northern Australia ◽  
Sea Snake ◽  
Pregnant Females ◽  
Sea Snakes ◽  
Catch Up ◽  
Specialized Diet ◽  
Trawl Catches ◽  
Northern Prawn Fishery ◽  
Closed Season

Trawlers catch up to 17 species of sea snake as bycatch in the Northern Prawn Fishery (NPF) in northern Australia. We examined the biological characteristics of 660 sea snakes caught by research, scientific observer and commercial vessels between 1986 and 1998 as part of a project to assess their vulnerability. Three species accounted for more than 75% of the total sea snakes caught. Hydrophis species were more common in unstructured habitats close to prawn trawling grounds, while Aipysurus species were the dominant species in areas having reef structure. Sea snakes were caught more frequently at night on commercial trawlers and even more were caught during the day by research trawling. Female sea snakes were caught more often than males for 10 out of 13 species examined. The proportion of mature sea snakes in trawl catches was high (67% males, 89% females). Juvenile sea snakes of most species are not caught suggesting there is little impact of trawling on recruits. We found all species breed annually, producing a few large young after a gestation period of 6-7 months. Litter size varied between 1 to 20 and young of most species were born during the NPF closed season (Nov-Mar). Except for Aipysurus duboisii, Disteira major and Hydrophis ornatus, pregnant females of most species were not more catchable by prawn trawls than non-pregnant females. The relative clutch mass had little effect on the catchability of pregnant females. Most sea snake species had a specialized diet, feeding on one to four benthic fish species and did not appear to be attracted into trawl grounds by the increased availability of discarded bycatch. Their reproductive characteristics mean that populations of many species caught by trawlers in northern Australia are potentially vulnerable.

scholarly journals Investigating the status of marital burnout and related factors in married women referred to health centers

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mahbobeh Nejatian ◽  
Ali Alami ◽  
Vahideh Momeniyan ◽  
Ali Delshad Noghabi ◽  
Alireza Jafari
Keyword(s):  
Marital Satisfaction ◽  
Significant Relationship ◽  
Married Couples ◽  
Married Women ◽  
Health Centers ◽  
Related Factors ◽  
Factors Affecting ◽  
The Status ◽  
Multistage Sampling ◽  
Emotional Burnout

Abstract Background Marital burnout is an important issue in marriage and many factors play an important role in this phenomenon. The aim of this study was to determine the status of marital burnout and the factors affecting married women who were referred to health centers because of it. Methods In this study, 936 women were selected by multistage sampling and data collection was performed using questionnaires of demographic and couple burnout. Data analysis was performed using SPSS software version 24. Results The mean (± SD) of marital burnout, in this study, was 55.46 (± 18.03) (out of 147 score). There was a significant relationship between the level of women's education with total marital burnout, and the subscales of somatic and emotional burnout (P < 0.05). A significant relationship was also observed between mandatory marriage and total marital burnout, as well as subscales of somatic, emotional, and psychological burnout (P < 0.05). A significant relationship was detected and observed between women's participation in training courses of communication skills and total marital burnout, inclusive of the subscales regarding psychological burnout (P < 0.05). The results of linear regression showed a significant relationship between mandatory in marriage, marital satisfaction, marriage duration, and husband's level of education with women's marital burnout. The variables were finally able to predict 12% of marital burnout variance. It should be noted that marital satisfaction had a higher effect on predicting marital burnout (P < 0.001). Conclusions Marital satisfaction was one of the effective factors in predicting marital burnout, so it can be concluded that it is necessary to pay more attention to this issue. Educational programs and examining the factors that enhance marital satisfaction are needed to prevent and reduce marital burnout in married couples.

Ecological and environmental factors affecting the foraging activity of the White-bellied Heron Ardea insignis (Hume, 1878) in Bhutan

2021 ◽  
pp. 1-18
Author(s):  
PEMA KHANDU ◽  
GEORGE A. GALE ◽  
SARA BUMRUNGSRI
Keyword(s):  
Relative Abundance ◽  
Habitat Restoration ◽  
Prey Species ◽  
Catch Per Unit Effort ◽  
Factors Affecting ◽  
Prey Biomass ◽  
Gravel Mining ◽  
Unit Effort ◽  
Prey Preferences ◽  
The Government

Summary White-bellied Heron Ardea insignis (WBH) is critically endangered, but we lack data on many aspects of its basic ecology and threats to the species are not clearly understood. The goal of this study was to analyse WBH foraging microhabitat selection, foraging behaviour, and prey preferences in two river basins (Punatsangchhu and Mangdechhu) in Bhutan which are likely home to one of the largest remaining populations of WBH. We also explored the relationship between the relative abundance of the WBH and prey biomass catch per unit effort within four foraging river microhabitats (pool, pond, riffle and run). Prey species were sampled in 13 different 100-m thalweg lengths of the rivers using cast nets and electrofishing gear. Riffles and pools were the most commonly used microhabitats; relative abundance was the highest in riffles. The relative abundance of WBH and prey biomass catch per unit effort (CPUE) also showed a weak but significant positive correlation (rs = 0.22). The highest biomass CPUE was observed in riffles while the lowest was found in the ponds. From the 97 prey items caught by the WBH, 95% of the prey were fish. The WBH mainly exploited three genera of fish (Garra, Salmo, and Schizothorax) of which Schizothorax (64%) was the most frequently consumed. This study provides evidence in support of further protection of critical riverine habitat and fish resources for this heron. Regular monitoring of sand and gravel mining, curbing illegal fishing, habitat restoration/mitigation, and developing sustainable alternatives for local people should be urgently implemented by the government and other relevant agencies. Further study is also required for understanding the seasonal variation and abundance of its prey species in their prime habitats along the Punatsangchhu and Mangdechhu basins.

scholarly journals Seasonal Variation Characteristics of Bacteria and Fungi in PM2.5 in Typical Basin Cities of Xi’an and Linfen, China

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 809
Author(s):  
Sen Wang ◽  
Wanyu Liu ◽  
Jun Li ◽  
Haotian Sun ◽  
Yali Qian ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Relative Abundance ◽  
Pathogenic Bacteria ◽  
High Throughput Sequencing ◽  
Fine Particulate Matter ◽  
Ecological Functions ◽  
Factors Affecting ◽  
Bacterial Phyla ◽  
Variation Characteristics ◽  
Bacteria And Fungi

Microorganisms existing in airborne fine particulate matter (PM2.5) have key implications in biogeochemical cycling and human health. In this study, PM2.5 samples, collected in the typical basin cities of Xi’an and Linfen, China, were analyzed through high-throughput sequencing to understand microbial seasonal variation characteristics and ecological functions. For bacteria, the highest richness and diversity were identified in autumn. The bacterial phyla were dominated by Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes. Metabolism was the most abundant pathway, with the highest relative abundance found in autumn. Pathogenic bacteria (Pseudomonas, Acinetobacter, Serratia, and Delftia) were positively correlated with most disease-related pathways. Besides, C cycling dominated in spring and summer, while N cycling dominated in autumn and winter. The relative abundance of S cycling was highest during winter in Linfen. For fungi, the highest richness was found in summer. Basidiomycota and Ascomycota mainly constituted the fungal phyla. Moreover, temperature (T) and sulfur dioxide (SO2) in Xi’an, and T, SO2, and nitrogen dioxide (NO2) in Linfen were the key factors affecting microbial community structures, which were associated with different pollution characteristics in Xi’an and Linfen. Overall, these results provide an important reference for the research into airborne microbial seasonal variations, along with their ecological functions and health impacts.

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