Net Fishing Research Articles

In-line identification of Pb-based pigments in fishing nets and ropes based on hyperspectral imaging and machine learning

Fishing lines, nets, and ropes represent a significant portion of plastic pollution in marine environments, and can contain hazardous additives. The development of less laborious and faster methods aiming at identifying plastic-related additives is therefore needed, in order to facilitate effective recycling. This work aims to develop an industrial inline method to identify lead-based pigments in fishnets by an industrial hyperspectral imaging (HSI) system working in visible-near-infrared spectral range (Vis-NIR, 450 to 1050 nm) and machine learning. A Vis-NIR spectral sample set comprising un-contaminated and lead contaminated (143 to 2430 mg L−1) plastic classes were used to build the classification model via Principal Component Analysis and clustering. The content of the samples was characterized by X-ray fluorescence (XRF), Attenuated Total Reflection (ATR-FTIR), differential scanning calorimetry, thermogravimetric analysis, and burning in astmospheric air. Fishnets containing lead-based pigments with lead concentrations > 1000 mg L−1 (0.1 wt%) were accurately identified by the industrial HSI, and the lead content was corroborated with ATR-FTIR and XRF measurements. In addition, lead contaminated plastic area and mass can be estimated via calibration curve using the pixels numbers vs mass of fibrous plastics with a detectability of 120 mg (R2 = 0.997).

A social wellbeing approach to the gendered impacts of fisheries transition in Gujarat, India

In this paper, we use the analytical lens of social wellbeing to interpret the history of livelihood change in the coastal village of Saiyad Rajpara in Gujarat over the past 70 years. We describe a broad narrative of transition from food scarcity to food security brought about by the introduction and intensification of bag net fishing in the village. This form of fishing has largely displaced the previous economic basis for livelihoods of uncertain daily wage labour. In a pattern common along the coast, an economy offering at best subsistence has shifted to one that is market-oriented, and which generates considerable surplus. We use the social wellbeing perspective to take stock of and order the complex effects of this transition. While the intensification of small-scale fishing in Saiyad Rajpara resulted in a general and marked material improvement in the lives of the residents of the village, the social relational benefits and subjective experience of change have been more mixed, particularly along lines of gender. A social wellbeing perspective offers an approach to fisheries governance that is more inclusive and sensitive to local experience.

Growth Patterns and Mortality of Lobster Panulirus ornatus from the Catch of Bottom Gill Net Fishers in the Western Waters of Tarakan Island

Large-bodied Panulirus ornatus lobsters are economically important because they are an aquatic biota. It is one of the most important commodities in the city of Tarakan. The aim is to analyze the growth patterns and mortality of P. ornatus from the West Waters of Tarakan City. Method using a quantitative descriptive. The purposive sampling method was used by dragging the gill net fishing gear to the P. ornatus lobster ground area, and the collection was carried out 16 times in 7 months (December 2021-July 2022). The results of P. ornatus showed that the male sex ratio was higher than the female. The growth model was allometrically negative, and the criteria for the condition index were fat and thin. The growth pattern of Model Von Bertalanffy males is slower than females. However, the growth rate to achieve asymptotic growth for males is faster than for females. The total mortality, catch mortality, and exploitation rate of males was higher than females. However, the mortality of the female nature was higher than that of males. P. ornatus should be managed in the waters of West Tarakan using the domestication and restocking technique to increase sustainability.

Formulation of Fuel Oil Consumption Estimation on The Fishing Vessels Through The Gill Net and Bubu Fishing Gears for Evaluating Fuel Subsidies in Bintan Regency - Indonesia

The largest percentage of expenditure in fishing operations using motor boats is Fuel Oil (BBM) which amounts to 40-50% of total operating costs. Inorder to ensure the smoothness and accuracy of the distribution of subsidized fuel for fisheries businesses, the Ministry of Marine Affairs and Fisheries issued Ministerial Regulation KP No.13 of 2015 concerning guidelines for the implementation of the issuance of recommendation letters for the purchase of certain types of fuel oil for capture fisheries businesses. In this study, an evaluation of the formulation was carried out to determine the estimated consumption of fuel subsidies on fishing vessels measuring 10-30 GT with Gill Net and Bubu fishing gear in Bintan Regency. In the calculation process, the estimated fuel consumption for fishing vessels must consider several aspects, namely the type of fishing gear, the distance to the fishing location, the power on the main and auxiliary engines, as well as the fuel coefficient and specific gravity used. Therefore, it is necessary to estimate fuel consumption by calculating the operating mode on each type of fishing gear. This is intended as an effort to provide a more precise estimate of fuel consumption.The method used in determining fuel estimates is with two different scenarios. In scenario I, the calculation of fuel consumption uses the formulation of Permen-KP No. 13 of 2015, with the formula used in the main engine is the power of the main engine, namely the Cfo and the duration of the capture operation per trip, while for the estimated measurement of the consumption of auxiliary machines, it is calculated 20% of the estimated fuel of the main engine. On the other hand, based on scenario II, the formulation of fuel consumption estimates still uses the formulation of Permen-KP No. 13 of 2015, but the evaluation is carried out by adding calculations of the catch operation time according to the type of Gill Net or Bubu fishing gear, the distance to the capture location, and the power of the auxiliary machine used. The results of this study found that there were differences in fuel consumption in the two types of fishing gear in each scenario. In scenario II, a ship using Gill Net fishing gear requires a greater fuel consumption of 44% thana ship with Bubu fishing gear. In addition, scenario II recommends adding 43% fuel for Gill Net ships and adding 39% fuel for Bubu ships. With this scenario II modeling, theproduction contribution obtained during the application of scenario II increased by 15% on the Gill net fishing gear and 17% on the Bubu fishing gear.

Habitats of House Sparrow Passer domesticus (Linnaeus, 1758) in Rameswaram Island, Tamil Nadu, India

This paper pertains to the nesting habitats of House Sparrow Passer domesticus with specific reference to population dynamics, nesting-related habits, nests, behaviours and other threats faced by these birds in Rameswaram Island. A total of 2,988 adult House Sparrows and 407 active nests were counted during the study. Of nests counted, 19% (n = 77) were solitary. The highest number of nests observed in a cluster was 9 (2 clusters). 60% of nests (n = 244) were found in concrete buildings, 39% (n = 159) in artificial nest-boxes, and 35% (n = 144) in cavities/crevices within buildings. House Sparrow population exhibited nesting plasticity, and 2% of nests were found constructed on vegetation. A wide variety of locally available materials, such as pieces of synthetic fishing nets, nylon ropes, and polythene papers were used for construction of nests. Sand and water bathing by birds were observed. Accidental fall of eggs and chicks, predation of nests by House Crows Corvus splendens, and unsuccessful attempts to predate adult birds by Black Kite Milvus migrans were observed, as well as opportunistic sightings of Shikra Accipiter badius.

Salmon evolve quickly as a response to intense harvesting of their prey

To persist in the face of climate change and human activities, organisms may need to adapt. We showed that Atlantic salmon from River Teno (between Finland & Norway) evolved over the last 40 years to mature earlier. Our data suggest it was due to indirect and direct effects of fishing: harvesting of capelin to feed farmed animals, and size selective net fishing in the river.

Exploitation status and spawning potential ratio of banana prawn (Penaeus merguiensis) after trawling ban in Kaimana, West Papua

Penaeus merguiensis de Man, 1888 is a prawn species with high commercial value and is a potential fisheries resource in Kaimana, West Papua, Indonesia. Formerly exploited by foreign fishing trawlers, the Indonesian government issued a national moratorium of foreign fishing ship licensing and trawling ban in 2014 and 2015, respectively. Consequently, the fishing activities in this area have shifted to local, small-scale vessels using trammel nets. This study aimed to determine the exploitation status and the spawning potential ratio (SPR) of P. merguiensis in Kaimana waters after the moratorium implementation, considering this species’ previous intensive fishing pressure. The study was conducted from April 2018 to December 2020 using 15,227 measurement samples. The optimal fishing season was observed from July to September, while the peak spawning season was detected between August and November. The carapace length (CLc) was significantly increased, suggesting the improvement of the banana prawn population over three years of trawling ban implementation. However, the exploitation rate (E) from 2018 to 2020 was 0.7%, and the SPR was 17%, implying that the prawn stock was still in an overfished condition. Therefore, fisheries management needs to regulate the efforts of trammel net fishers to avoid further fishing pressure in Kaimana waters.

School Dropout an Evil, who is Socially Responsible? A Study

School Dropout is a serious social evil which when unattended will have a long run impact in all the sphere of the society. This particular issue should be given utmost importance by the teachers in schools and parents and elders in families. The stakeholders should play a pro-active role in dealing with this problem.
 The major reason of dropout is widely hinted at the economic backwardness of the school children. Apart from this cause there are many other causes ranging from issues in the family, at home and even in schools, liking and disliking of schools and teachers also contribute to the cause of dropout. This issue of dropout has become more serious especially after the disaster of Tsunami in 2004.
 The issue of dropout has to be viewed in a different angle in fishing / coastal villages. The fishing occupation is no doubt a risky job but it has been lucrative. High lucrative in this profession is positively correlated with the investment in mechanised boats and fish nets. The scenario of this dropout problem took an ugly turn post Tsunami. Post Tsunami, relief, rehabilitation and reconstruction was well undertaken by the Government in a very large scale and equally by the Third Sector (NGOs). The relief was also in the form of Mechanised & Fibre Boat (FRB) distributed by many NGO. Prior to Tsunami the number of FRB was very less in number, so the labour force required was also minimal. The number of FRB increased post tsunami which resulted in labour shortage. This also paved way for the entry of children in the profession of fishing saying goodbye to studies. Was this the starting point of School Dropout? At the backdrop of this scenario, the present research has been undertaken. The present research has taken care to highlight the socio-economic profile of the dropouts in the coastal/fishing villages of Karaikal District, Union Territory of Puducherry. The results support the following statement that “Disaster has a direct bearing on the Education of Children”.

An investigation of acoustic deterrent devices to reduce cetacean bycatch in an inshore set net fishery

In Europe, problems with the use of pingers on larger fishing vessels have raised the question as to whether pingers would be practical on smaller vessels, which are a large proportion of the European static net fishing fleet. In this study, four netting vessels less than 10m long used AQUAmark pingers on part of their nets off the southwest coast of Britain over a 12 month period. Boat skippers recorded ease of use. Acoustic click detectors were deployed on test and control nets to assess the response of cetaceans to the pingers. No significant practical problems, apart from premature failure of pingers, were encountered. During the study, only one harbour porpoise was bycaught, in an unpingered net. In 650 days of acoustic data from pingered and non-pingered nets, matched by location, date and boat, there was a highly significant reduction in the number of porpoise clicks recorded at nets with pingers to 48% of the number predicted from the number recorded at control nets (range 35–51%). To assess habituation, single, modified pingers that were active for alternate seven hour periods were moored below a click detector at two sites, one of which has strong tides and high levels of associated ambient noise. This study showed a stronger pinger effect at the quiet site and a much reduced effect at the noisy site. There was evidence of a period of exclusion of porpoises following pinger use that could exceed seven hours, and no evidence of habituation. Results suggest that pingers are practical on small vessels, that they reduce harbour porpoise activity around nets and are therefore likely to reduce bycatch. Easier means of detecting pinger failure are needed. Pingers should be considered as a bycatch mitigation method in small vessel fisheries using bottom set nets.

A simplified approach for fatigue life prediction of aquaculture nets under waves and currents

With increasing trends to move fish farms to more exposed locations engineers need quick and accurate tools for creating initial design proposals. In this paper, a simplified analytical model for estimating the axial force in the ropes supporting the fish net is presented. Hydrodynamic loads acting on the net are calculated using a state of the art screen model. The simplified analytical model is a quasi-static solution based on the principle of virtual displacements. The assumed mode shape in the calculations is a simplification of the actual quasi-static displacement shape under combined wave and current loading in view of the high natural frequencies of pre-tensioned ropes compared to wave frequencies. The results from the simplified calculations are compared to numerical simulations performed in RIFLEX. The simplified method is extremely efficient with regard to computation time compared to the numerical simulations and is well suited for preliminary design of fish nets.

Environmental DNA survey to detect an endemic cryptic fish, Anablepsoides cryptocallus, in tropical freshwater streams

Abstract Martinique island is a biodiversity hotspot in the Lesser Antilles that harbours many endemic species. One of these, Anablepsoides cryptocallus, also known as ‘Poisson gale’, is the only endemic freshwater fish of Martinique and a species with a poorly understood distribution range. In this study, an environmental DNA (eDNA) detection protocol was developed, validated, and optimized, targeting a short fragment (125 bp) of the A. cryptocallus COI mitochondrial gene, to investigate the presence of this species in Martinique. Fifty‐seven sites spread over 43 permanent rivers and two wetlands were sampled using both eDNA and conventional fishing (dip net capture). Presence was confirmed in 27 sites using eDNA detection, and in nine sites by dip net fishing. eDNA‐based detection of A. cryptocallus was effective and less time‐consuming than conventional fishing, making it a relevant tool for future studies throughout the island. Even though A. cryptocallus was found to be present in a significant number of sites, many sites previously known for this species were found to be negative, highlighting the need for continuous monitoring. There is now an urgent need to propose protection status for this endemic species to preserve its preferential habitats, as these are being increasingly threatened by human activities that are leading to habitat loss and fragmentation.

Characteristics of coral reef fisheries in the Wakatobi islands

Wakatobi National Park has a diverse fish population, and its conservation potential for reef fish resources is quite large. As a result, to be sustainable, the exploitation of these resources must be properly managed. This study aims to look into the characteristics of reef fish fisheries, such as species composition, catch, fishing ground, and fish length. The outcomes are hoped to be beneficial in monitoring the management of the resources. This research was conducted in April-November 2018 in Wakatobi, Indonesia. Analytical methods process the data. The results showed that gold spotted rabbitfish (Siganus punctatus), parrotfish (Hipposcarus longiceps), emperor (Lethrinus lentjan), grouper (Epinephelus sp), and trevallies (Caranx sp) dominated the total catch from muroami, speargun, and hand line. Muroami boats have a higher average CPUE (212 kg/trip/month) than speargun (29.0 kg/trip/month) and handlines (13.0 kg/trip/ship). Some of the reef fish caught in Wakatobi National Park is small and immature. Muroami net, speargun, and handline fishing are mostly done in the southern part of the Wakatobi National Park area, around Binongko Island. One of the management actions undertaken by Wakatobi fishermen is fishing inside the management zone that has been established, namely the local use zone.

Reprodução do black-bass invasor Micropterus salmoides (Lacepède, 1802) em um reservatório neotropical, com sugestões para manejo e controle

Abstract Aim The largemouth bass Micropterus salmoides was introduced in more than 50 countries for the purpose of sport fishing. In Brazil, records date from 1922, and nowadays many populations are known to occur in the southern region. Here we investigated the reproductive biology of this species in a small reservoir in southern Brazil, to understand the role of the reproductive strategy in the invasion process and assist in its management. We conclude with suggestions for the management in local scale, as this species can bring relevant problems to the public supply through trophic cascade and other negative effects. Methods Samples were performed with different methods, between May 2011 and April 2012. All fishes were measured, and the reproductive season was determined through the relative frequency of reproductive stages and the gonadosomatic index. Sex ratio was calculated monthly and for each total length (TL) class and compared with the estimates presented in the literature. Total length at maturity (L50, length at which 50% of the individuals were mature) was estimated for females, males and the entire study population. Results A total of 565 individuals of M. salmoides were analyzed. Overall sex-ratio did not differ significantly. The monthly distribution of the gonadosomatic index for females and males showed higher values between August (late winter) and November 2011 (austral spring). ��-Binomial modelling of sex-ratio data of native (n=1) and introduced populations (n=7) showed a lower proportion of females in its native range. All individuals > 21.5 cm TL were mature (L95), and L50 was calculated at 18.7 cm TL. After the reproductive period, an increase in the abundance of young individuals (≤ 7.0 cm TL) was registered, corresponding to 50% of all individuals collected. The relative frequency of mature individuals and the variation in the gonadosomatic index indicate a prolonged spawning period during the austral spring, coinciding with the increase in temperature. Conclusions Results suggested that some changes in life history traits, such as the early sexual maturation and the long reproductive period, coupled with a remarkable adaptability, may have facilitated the establishment of M. salmoides populations in this reservoir. The illegal and intentional stocking by anglers plays a central role in the introduction and dispersal of M. salmoides in Brazil. We encourage studies on the sanitary quality of this fish for human consumption, so that massive campaigns of education the population to encourage capture and consumption are implemented by the competent authorities as a control measure in local scale, combined with targeted samplings with artificial baits during the reproductive period, identification, and removal of nests and fingerlings using electric fishing or trap nets during the recruitment period.

Fish diversity of the Beki River, Assam, India: Present status and conservation needs

The state of Assam in India is recognized as one of the hotspots of freshwater fish diversity. Beki River is an important tributary of the Brahmaputra River. A significant decrease in freshwater fish in this region has been a major source of concern in recent years. The fish diversity of this region has encountered various anthropogenic threats that have led to the loss of biodiversity. In this study, fish diversity was studied in six fish landing zone of Beki River and 31 species of fish were recorded. The ichthyofaunal diversity of the Beki River belongs to the following families - Bagridae (9.67 %), Balitoridae (3.22 %), Belonidae (3.22 %), Claridae (3.22 %), Cyprinidae (64.51 %), Mastacembelidae (3.22 %), Osphronemidae (3.22 %), Schilbeidae (6.45 %) Siluridae (3.22 %). The study recorded Cypriniformes as the most dominant group and Cyprinidae as the most species-rich family.The rich diversity of fish like Ailia coila, Tor putitora, Cirrhinus mrigala, Puntius conchonius, Puntius gelius, and Puntius terio was recorded in the Beki River. Exotic species like Clarias gariepinnus, which was reported in the present study, are of major concern as they may be a threat to the indigenous species in near future. Species like Puntius phutunio, Systomus sarana, and Clupisoma garua are now facing population depletion. Shannon index of 3.33 at L5 (Uttarganakguri), 3.21 at L4 (Nizdamaka), and 3.11 at L1 (Gobardhana) indicate good diversity while 2.98 at L2 (Safakama), 2.97 at L3 (Dumnighat) and 2.88 at L6 (Madulijar) sampling sites indicates moderately polluted water. There are some serious threats in Beki River regarding fish conservation and management, which includes sand mining, use of fertilizers and extensive fishing, and non-regulation of the mesh size of fish nets. Raising awareness among the fisherman and strict laws implementation can help to regulate the water quality of the river and also restore the fish diversity.

General macro-litter as a proxy for fishing lines, hooks and nets entrapping beach-nesting birds: Implications for clean-ups

Fishing lines, hooks and nets represent a sub-category of macro-litter potentially entrapping plover birds nesting on sandy beaches. Here, during a winter period, the accumulation pattern of both general beach litter and fishing lines, hooks and nets was analysed on four central Italy beaches. Despite the active monthly litter removal by clean-ups, there was not a decrease in its density during the winter period, due to the continuous accumulation by frequent winter storms. However, the entrapping litter was very low (<2.5 % of the general litter) and appeared directly correlated to the general litter density. Following a DPSIR approach, the general litter can act as an indirect pressure indicator (proxy) of the amount of entrapping litter. Therefore, an increase in general macro-litter should alarm those involved in the conservation of entanglement-sensitive bird species, such as plovers, suggesting that they should implement high-frequency clean-up activities aimed at removing it.

Collateral Effects of Insecticide-Treated Nets on Human and Environmental Safety in an Epidemiological Model for Malaria with Human Risk Perception.

Malaria remains a major health problem in many parts of the world, including Sub-Saharan Africa. Insecticide-treated nets, in combination with other control measures, have been effective in reducing malaria incidence over the past two decades. Nevertheless, there are concerns about improper handling and misuse of nets, producing possible health effects from intoxication and collateral environmental damage. The latter is caused, for instance, from artisanal fishing. We formulate a model of impulsive differential equations to describe the interplay between malaria dynamics, human intoxication, and ecosystem damage; affected by human awareness to these risks and levels of net usage. Our results show that an increase in mosquito net coverage reduces malaria prevalence and increases human intoxications. In addition, a high net coverage significantly reduces the risk perception to disease, naturally increases the awareness for intoxications from net handling, and scarcely increases the risk perception to collateral damage from net fishing. According to our model, campaigns aiming at reducing disease prevalence or intoxications are much more successful than those creating awareness to ecosystem damage. Furthermore, we can observe from our results that introducing closed fishing periods reduces environmental damage more significantly than strategies directed towards increasing the risk perception for net fishing.

СТРУКТУРНI ПОКАЗНИКИ ПОПУЛЯЦІЇ КАРАСЯ СРІБЛЯСТОГО (CARASSIUS GIBELIO B.) КРЕМЕНЧУЦЬКОГО ВОДОСХОВИЩА

Ukraine ranks first in Europe in the number of natural water bodies. These abundant water resources are the source of significant fish resources, which are effectively exploited by the fishing industry. Rationalization and equal distribution of the commercial load, the reduction of the commercial pressure on the main fish species has always been an urgent issue. This can be achieved by shifting the focus of fishing to other types of fish, which will allow rational use of the entire complex of commercial species. The Prussian carp Carassius gibelio (Bloch, 1782) is among such promising objects of fishing - a massive, small-particle species, which in certain water bodies of Ukraine has displaced other minor commercial fish species and formed stable numerical populations. &#x0D; A decisive role in the age structure formation of the Prussian carp population was played by the increase in the specific number of middle and older age groups, which is associated with an insufficient level of commercial load. Thus, the variation series of this species in the commercial catches of 2021, unlike other species, had the form of a double-peaked curve, which was formed due to the loss of size classes of 25-28 cm. According to the Fishing Rules and the Regime of Fishery Operation of the Dnipro Reservoirs in force today, nets with a step are allowed hole a=38-49 mm and 70 mm and more. This distribution of commercial load selectivity reduces pressure on bream and bream populations. However, it also causes a significant increase in the stock of Prussian carp. And this alien species has formed abundant populations in the Kremenchuk Reservoir. Thus, its average annual catch in the period 2000-2020 increased from 44.6 to 462.4 tons or 10 times in 20 years. &#x0D; We should note that Prussian carp occupied an insignificant segment of the catch - no more than 0.1% by weight in the traditional commercial set of gill nets (a=75-90 mm) at the Kremenchuk Reservoir, while, in the 50-60 mm mesh size nets this species is dominant with a share in catches of up to 60% by weight. Thus, the main indicators that characterize the fisheries and environmental protection components of gill net fishing are a mesh size that deals with part of the main target fishing objects, size and weight indices, and bycatch of immature commercially valuable species. The gill nets with 50-60 mm generally meet the requirements for the current legislation and might be used for targeted harvest of the species in the littoral zones. Considering the need to intensify fishing for Prussian carp and its high actual specific mass in catches of nets with a mesh size of 50-60 mm, the implementation of specialized fishing for this species in the Dnieper reservoirs can be considered as a means of optimizing the use of the formed bioresource for the commercial fishery. In order to minimize the negative impact of this fishing on the structural and functional indicators of the bream population, specialized fishing should be focused on the areas of accumulation of Prussian carp, i.e. it is a specialized fishery with a share of Prussian at least 50%. The necessity of the meliorative capture introduction aimed to downgrade the reproductive core of the population of this alien species to prevent its uncontrolled population growth.

Production, Fishing Season and Fishing Ground of the Dominant Fish (Euthynnus affinis, Mene maculata, Leiognathus equulus) Caught by Boat Seine in Palabuhanratu Indonesia

Boat Seine net is a very productive fishing gear in Nusantara Fisheries Port (NFP) Palabuhanratu. Boat Seine was a fishing unit that has the third largest contribution to the provision of fish stocks in 2019, which is 9% of the total production volume of NFP Palabuhanratu after lift net (40%) and longline (35%). The purpose of this study was to analyze the composition of the main catch, productivity, fishing season and to analyse the fishing ground in Palabuhanratu Bay. The type of data collected in this study was quantitative data. Primary data from interviews and field observations of fish landing activities at Palabuhanratu in October 2020 were used to compile this study's data, which included the type of fishing gear used, the composition of the types, and the production of the catch. Secondary data collected were monthly catches and trips made by Boat Seine fishing units. By analyzing the data of Boat Seine net fishing from 2015 to 2019, descriptive analysis method was used to investigate the composition of Boat Seine net catch. The results of the research showed that mackerel (Euthynnus affinis), moonfish (Mene maculata), and ponyfish (Leiognathus equulus) are the dominant fishes caught at the Palabuhanratu waters. The productivity level of Boat Seine net was 348 Kg/Trip in 2015, which increased to 603 Kg/Trip in 2019. The mackerel season occurs around May to September and November. Moonfish fishing season occurs in March, September and October. Ponyfish fishing season occurs in January, March, May, October, November, and December. Boat Seine net fishing grounds in the waters of Palabuhanratu Bay are relatively stationary around the waters of Palabuhanratu Bay.Keywords: CPUE, Fishing Area, Fishing Season Index, Productivity

Catalytical thermal conversion of waste fishing nets for a higher added value energy products generation and caprolactam recovery

The ongoing eutrophication processes and water pollution caused by marine plastic waste are relevant ecological problem. Collected wastes are possible alternative feedstock for additional higher added value energy product generation. Moreover, caprolactamis the main compound of nylon-6 waste fishing nets and its recovery conserves natural resources, maximizes waste economic performance, and closes the circular economy loop of the fishing net industry. In order to contribute to the creation of circular economy, investigation of pyrolysis process and the effect of catalyst synergy with different temperatures on the formulated products has been performed. This work aims to analyse the used fishing nets (FN), using TGA-DTG-FTIR systems and mini pyrolysis plant. Experiments were conducted with Y-type zeolite and ZSM-5 as catalysts with a ratio of 1 by 3 and 1 by 8, respectively. Micro-thermal analysis using the TGA-DTG-FTIR system was processed for feedstock characterization purposes, which showed that the fishing gear has one minor decomposition peak around 200 °C, and the major one around 450 °C, with a total weight loss of 88 wt%. Pyro-oils analysis showed that the main fractions could be assigned to aromatic and aliphatic hydrocarbons, such as naphthalene, styrene, and toluene. Moreover, the recovery of caprolactam shows a possibility to obtain not only energy products, but also higher added value chemical derivatives. Temperature and catalyst synergetic approach influence for the recovered products investigation showed the optimum conditions as 700 °C for the highest purity and quality products generation. Based on the results, catalytic thermal treatment at 700 °C with Y-Type could be adapted as a promising technique for extracting of caprolactam with a high yield (96 %).

Mosquito Net Fishing as a Normal Accident and the Roles of Traditional and Bureaucratic Authority

In the 1980s, malaria researchers experimented with treating mosquito nets with pyrethroids chemicals to kill mosquitoes (insecticide-treated net or ITN). In the mid-2000s, world health agencies determined that ITNs should be distributed freely. Since then more than two billion ITNs have been distributed throughout malaria-endemic countries. In regions where fishing is an important economic activity the ITNs have been repurposed for fishing. The practice has been found to have very negative effects on fisheries. Using Perrow’s Normal Accident Framework (NAF) we explain how interest-driven parties ignore local conditions to cause ‘accidents’ such as mosquito net fishing (MNF). In addition, we employ Weber’s concepts of bureaucratic and traditional authority to understand how local actors address an ‘accident’ not of their making. Then, using two focus group interviews with Traditional Leaders and Zambian Government Fishery Personnel we shed light on how local sociohistorical conditions interact with imposed, massive, and complex sociotechnical systems.