Purse Seine Capture Research Articles

Economic and Marketing Study of Purse Seine Catch Results in Bone Bay Waters, Bone Regency

Harvesting marine biological resources especially fish, is still largely dotted with fishing activities. One of the fishing businesses engaged in fishing that has already developed in Indonesia, especially in the South Sulawesi Bone Bay is a ring trawl business (Purse seine). The magnitude of the potential of fisheries in the bone bay led to the formation of a large number of purse seine fishing business units in Bone district. However, erratic natural conditions make production yields non-permanent so it is necessary to know how much this business is still feasible to continue. In this purse seine catch production flow, aspects of marketing and distribution anaises are an important part of knowing the effectiveness of production to support the economy of society. The research was conducted from October to November 2020. In this study the income received by the purse seine capture business unit in bone bay was 1,115,964,357.52/year and indicated that the purse seine business carried out by the fishing business actor was feasible to develop by the division between receipts and costs has a value of more than one (>1). Based on the Marketing aspect the value of marketing efficiency of purse seine catches is set according to the marketing channel value <1 which means it can be said that both channels are efficient marketing on each fish commodity.

The Effect Of Setting Time And Hauling Purse Seine On Catches At KM Bangkit Lautan Jaya5

The purpose of the study was to determine the effect of the length of time setting and hauling purse seine on the caught fish. The object of study is KM. Rising Lautan Jaya 5. The study was conducted from 1 to 4 June 2022 at the PPS Nizam Zachman Ocean Fishing Port in Jakarta. This study adopted a simple linear regression analysis to determine the correlation between setting time and hauling purse seine to caught fish. The results of the analysis in this study showed a relationship between the length of time and hauling of the catch in purse seine capture operations. The results of the normal distributed data test were 0.079 and 0.200, and there was a linear relationship of 0.783 and 0.880 so that the regression test results of 0.004 and 0.001 were found. Thus the results of the regression test can be interpreted to mean that there is an influence between the length of time setting and hauling on the catch

Composition and Catch Rate of Purse Seine Fishery Unit at the Tegal Fish Landing, Central Java

Purse seine fishing gear is one of the fishing gear used by the fisherman at the Tegal Fish Landing to catch pelagic fish. This study aims to analyze the composition of purse seine catches and catch rates based on the number of catches and trips to sea, determine the selectivity of purse seine fishing gear base on the number and species. The research method used survey methods and data in quantitative analysis, the analysis of the composition of the catch is secondary to the volume of purse seine catches at Tegal Fish Landing throughout September to November 2019. The capture rate was calculated using secondary data on the number of trips and the total production of purse seine at the Tegal Fish Landing from 2014 to 2018. Selectivity of puse seine fishing gear using primary data includes the number and weight of catches, identification of fishing gear, work equpment, safety equipment, supplies, navigation tools, accident history. The dominant variety of catch species was small pelagic fish, namely Decapterus macrosoma, Sardinella lemuru, and Rastrelliger kanagurta. The largest percentage of catches in September was 52% Decapterus macrosoma, 13% Sardinella lemuru, and Rastrelliger kanagurta. The location of the fishing grounds is in the WPP area 712 and 713 the average CPUE purse seine per year at Tegal Fish Landing was 26.710 kg or 26,7 tons per trip for each vessel. This shows that purse seine capture productivity was still quite low when compared to the size of Gross Tonnage. Purse seine gear for five fishing vessels that landed at Tegal Fish Landing selectively. During the study the proportion of the amount and weight of the five vessels was more thant 60%.

The analysis of the influence of running cost, shore cost and labor cost, towards profitability at the purse seine capture fisheries business units in the District of Seram Bagian Barat

Maluku is one of the provinces which has extensive fishery potential. However, the utilization of fishery potency in the District of Seram Bagian Barat’s maritime territory as one of the fishery management areas in Maluku, only reaches 40%. It shows that there is a huge opportunity for the development of capture fisheries business in the District of Seram Bagian Barat. The output determinants of the purse seine capture fisheries business are running cost, shore cost, and labor cost. The number of samples in this research is 60. Using the purposive sampling method, the samples are collected from the data of 20 business units for 3 consecutive years (2016-2018). This research is a Descriptive research with quantitative approach, which profitability is measured by ROI (Return On Investments) and the data analysis technique applied is the multiple linear regression with the smart PLS 3.0 program. The research is resulted in several conclusions. First, running cost variable has a positive and significant influence towards profitability (ROI), which proves that the District of Seram Bagian Barat’s maritime territory is still in the state of under exploited for small pelagic fish. Second, shore cost variable has a negative and significant influence towards profitability (ROI) which describes that the distance between fishing based to the target market is considerable obstacle. Third, the labor cost variable has a positive influence towards profitability (ROI), which shows that the amount of catch is not only determined by the number of crews and the size of the net but also by the skills and abilities of each crew to perform their respective duty correctly.

Physiological and flesh quality consequences of pre-mortem crowding stress in Atlantic mackerel (Scomber scombrus).

In commercial wild capture pelagic fisheries it is common practice to crowd catches to high densities to allow efficient pumping onboard. Crowding during the final stages of purse seine capture for small pelagic species often results in intense and sustained behavioural escape responses. Such a response may trigger a shift in energy production from aerobic to anaerobic pathways and result in metabolic acid accumulation and exhaustion of intracellular reserves of ATP. Where there is insufficient time or opportunity to recover to physiological equilibrium before death, pre-mortem stress may be an important determinant of fillet quality, as has been shown for a variety of farmed fish species. However, there is currently a lack of knowledge related to the flesh quality implications of capture stress for wild captured species in European waters. Here we show that crowding results in a physiological stress response that has consequences for flesh quality in the wild captured species Atlantic mackerel (Scomber scombrus). Using small schools in tanks and aquaculture net pens in three separate experiments, we found crowding results in physiological changes in mackerel consistent with an acute stress response and anaerobic metabolism. Consequently, we found crowded fish had more acidic pre- and post-mortem muscle pH as well as indications of faster onset and strength of rigor mortis and increased cathepsin B & L activity. We examined fillet flesh quality after two and seven days of ice storage and found reduced green colouration, increased gaping (separation of muscle myotomes) and reduced textural firmness associated with fish which had been crowded. However, the effects on quality were dependant on experiment and/or storage time. These results indicate the potential of crowding capture stress to influence the flesh quality of an economically important species and may have important implications for the wild capture pelagic fishing industry.

Effects on individual level behaviour in mackerel (Scomber scombrus) of sub-lethal capture related stressors: Crowding and hypoxia.

Stress to fish during harvest in wild capture fisheries is known to negatively influence subsequent survival in catches that are released. Therefore, if fisheries are to be conducted sustainably, there is a need to promote good fish welfare during the capture process. Purse seine fishing is a widespread and efficient fishing method. However, capture and release of fish from purse seines (a process called “slipping”) can result in extremely high mortality in small pelagic schooling species. The objective of this study was to establish behavioural indicators of sub-lethal stress in Atlantic mackerel (Scomber scombrus) that may be used to set safe threshold limits for use in commercial purse seine fishing, in order to ensure good fish welfare and thereby minimise slipping mortality. Controlled mesocosm scale experiments with schools of mackerel in net pens were undertaken to determine behavioural responses to simulated purse seine capture stressors of “crowding”, “hypoxia” and “crowding & hypoxia”. Crowding (at 30 kg.m-3) was achieved by reducing the volume of the net pen, while hypoxia (to 40% oxygen saturation) was achieved by surrounding the net pen with a tarpaulin bag to prevent water exchange. Using video analysis, we investigated behavioural responses in nearest neighbour distances, nearest neighbour angular deviations, tail beat amplitude and tail beat frequency (TBF). Of the metrics considered, only TBF showed a response; a significant increase to “crowding” (42% increase) and “crowding & hypoxia” (38% increase) was found. The increase in TBF in response to “hypoxia” alone (29% increase) was not significant. We therefore conclude that increases in tail beat frequency may be used as an indicator of sub-lethal purse seine capture stress in mackerel that may have utility in minimising post slipping mortality.

Dermal injuries caused by purse seine capture result in lasting physiological disturbances in coho salmon

Fish vitality can be measured by classifying reflex impairments (i.e., a visual impression of the ability to respond to induced stimuli) and visible injuries. These metrics can predict survival probability following release from fisheries, and monitoring physiological disturbances following capture can help understand mechanisms of mortality. To test the hypothesis that severity of injury and reflex impairment influences the time course of physiological recovery, coho salmon (Oncorhynchus kisutch) were held for up to 84-h following capture by purse seine. We classified reflex impairments and visible dermal injuries, and through repeated blood sampling, assessed metrics indicative of stress, exhaustion, and osmoregulatory disturbances. Reflex-impairments and blood lactate levels suggested fish were exhausted upon capture but recovered after 48 h. Conversely, fish with dermal injuries showed disruptions to ion homeostasis that were greater in more severely injured fish and increased over time. While reflex impairments may predict short term post-release mortality, the prolonged physiological disturbances caused by dermal injuries are likely to be responsible for delayed mortality; our results suggest that disruptions to ion homeostasis is a possible mechanism of post-release mortality.

Effects of different slipping methods on the mortality of sardine, Sardina pilchardus, after purse-seine capture off the Portuguese Southern coast (Algarve).

The effects of two different slipping methods on the survival, physical and physiological response of sardines, Sardina pilchardus, captured in a purse-seine fishery were investigated in southern Portugal. Sardines were collected and transferred into holding tanks onboard a commercial fishing vessel after being captured, crowded and deliberately released using two slipping procedures: standard and modified. The standard slipping procedure aggregated fish at high densities and made them “roll over” the floatline, while the modified procedure aggregated the fish at moderate densities and enabled them to escape through an opening created by adding weights to the floatline. Both slipping methods were compared with minimally harmed non-slipped sardines (sardines collected from the loose pocket of the purse seine). Survival rates were monitored in captivity over 28 days using three replicates for each treatment. The estimated survival of sardines was 43.6% for the non-slipped fish, 44.7% for the modified slipping and 11.7% for the standard slipping treatments. Scale loss indicated the level of physical impact experienced, with dead fish from the non-slipped and modified slipping technique showing significantly lower scale loss than those fish from the standard slipping treatment within the same period. Of the physiological indicators of stress measured, cortisol, glucose, lactate and osmolality attained peak values during slipping and up to the first hours after introduction to captivity. This work indicates that although delayed mortality after release may be substantial, appropriately modified slipping techniques significantly enhance survival of slipped sardines.

Behaviours of Atlantic herring and mackerel in a purse-seine net, observed using multibeam sonar

To ensure efficient and sustainable purse-seine fisheries, the catch process must be monitored to better understand the reactions of fish to the gear. In this study, we monitored the behaviours of herring (Clupea harengus) and mackerel (Scomber scombrus) schools during purse-seine capture using a multibeam imaging sonar (Simrad MS70, 75–112 kHz) mounted on a research vessel. The fish behaviours differed between species and purse-seine sets. For both species, the acoustic volume backscattering coefficient increased as 0–80% of the seine was hauled aboard, indicating a corresponding increase in fish spatial density. This increase was significantly greater for herring than mackerel. As 0–40% of the seine was hauled aboard the fishing vessel, schools changed their spatial distribution and volume independent of seine hauling, while for some schools, depth and height decreased. The acoustic volume backscattering strength was up to 25 dB higher in the centre of the school than in the edges. The average lateral target strength was estimated for individual fish in the captured herring schools, and the effect of incident angle on the backscattering strength is considered.

Southern bluefin tuna (Thunnus maccoyii) shed tags at a higher rate in tuna farms than in the open ocean — two-stage tag retention models

Tag shedding rates are estimated for southern bluefin tuna (SBT, Thunnus maccoyii) from double-tagging data arising from two tagging studies run in the 1990s and 2000s. Since the early 1990s, a high proportion of SBT tag recoveries has been sourced from juveniles captured by purse seine vessels in the Great Australian Bight and transferred to tuna farms off Port Lincoln in the state of South Australia. When tags have been shed by wild-caught SBT fattened in tuna farms, it is generally not known if the tags were shed in the open ocean before purse seine capture or after purse seine capture while the fish were on farm. Using a Bayesian approach, we fit separate tag retention curves for time in the ocean and time on farms as Weibull distribution reliability functions. The study suggests SBT shed tags at a much higher rate in on-farm enclosures than in the open ocean. Biofouling on tags in tuna farms may contribute to higher tag shedding rates.

An investigation of reactive behavior of yellowfin tuna schools to the purse seining process

The movement parameters of yellow fin tuna schools were analyzed by means of scanning sonar in tuna purse seine capture situations in the Oman Sea in June 2010. There was significant difference in swimming speed and radial swimming direction between the escaped and captured schools. In escaped cases, the fish schools swam faster with mostly horizontal avoidance behavior to the sound stimuli from the surrounding vessel and escaped capture under the sinking net at last. The swimming speed of the schools in two occasions was correlated to the vessel’s speed. Some alternatives of new constructions of the nets with regard to the sinking speed are discussed that may reduce the potential problem of escape capture during purse seining process.

Measurement of fish school abundances in shallow sea using omnidirectional multibeam sonar

Previous studies had been constructed in the use of commercial scanning sonar to estimate the abundance of pelagic fish school. However, a relatively narrow dynamic range and lack of linear signal processing limited the application of sonar. In this research, quantitative omnidirectional multi-beam sonar (FSV30 research version, 24 kHz, Furuno) was used to investigate a fish school in a shallow area. The raw volume backscattering strength signal (RSV, output signal with 20<th>log<th>r TVG and coefficient of multiple echo) of the fish school echoes were recorded and then its biomass was confirmed using purse seine capture. In postprocessing, the fish school echoes were extracted from the sonar echogram using the image processing method (polygon and a low-pass filter). The relationships between a school’s biomass, its echo area, the maximum, and the average RSV of each ping were considered for various species. Results showed a positive correlation between the sonar-measured school area and school biomass, but no correlation between the RSV and school biomass. Also, the echo integration method for sonar survey using RSV in broad area and methods for averaging the target strength (TS) in three dimensions with respect to echo integration method were also discussed.

Avoidance behaviour of herring ( Clupea harengus) and mackerel ( Scomber scombrus) in purse seine capture situations

The avoidance behaviour of herring and mackerel has been quantified by means of a true motion sonar in purse seine capture situations. Schooling herring swam at an average speed of 2.5–2.8 body-lengths s −1, and the mackerel schools about 1 bodylength s −1 faster. There were great variations in swimming speed and pattern of movement between the schools. The schools of both species usually avoided the vessel horizontally, and a relation between the avoidance and the sound emission pattern of the vessel was indicated. Shoaling herring was easy to capture at night, whereas both herring and mackerel schools escaped capture in about half of the sets in daylight. The results are discussed in relation to construction and operation of purse seines.

Predictable swimming behaviour of schools in purse seine capture situations

Sonar observations of herring, mackerel and sprat schools in purse seine capture situations in the North Sea and off the Norwegian coast revealed rather constant swimming behaviour of individual schools. However, there were large variations between the schools, and also differences between species. The consistency of the swimming behaviour nevertheless enabled development of a simple method to forecast the position of schools. The method may give the opportunity for position prediction on true-motion sonar in real capture situations.