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Journal articles on the topic 'Catch-rate'

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Published: 4 June 2021
Last updated: 30 January 2023

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1

Hjerne, Olle, and Sture Hansson. "Constant catch or constant harvest rate?" Fisheries Research 53, no. 1 (September 2001): 57–70. http://dx.doi.org/10.1016/s0165-7836(00)00266-6.

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2

Hoenig, John M., Cynthia M. Jones, Kenneth H. Pollock, Douglas S. Robson, and David L. Wade. "Calculation of Catch Rate and Total Catch in Roving Surveys of Anglers." Biometrics 53, no. 1 (March 1997): 306. http://dx.doi.org/10.2307/2533116.

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3

Widodo, Agustinus Anung, and Mahiswara Mahiswara. "CATCH RATE AND CATCH COMPOSITION OF FISH TRAWL BASED IN SIBOLGA, NORTH SUMATERA." Indonesian Fisheries Research Journal 17, no. 2 (February 9, 2017): 63. http://dx.doi.org/10.15578/ifrj.17.2.2011.63-73.

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To obtain data and information of fish trawl fishery performance operated in the Indian Ocean, a research was carried out through observation on board by observers as well as port sampling inSibolga Fishing Port by enumerators in September 2007, with the aimed to study the performance fish trawl fishery. These include fleet structure, trawl net design and construction, catch, fishing trip, fishing ground, and fishing operation. Results of research showed that there were 71 registered fish trawlers in Sibolga Fishing Port and only 25 boats active due to increasing of fuel price. The fleet structure of fish trawler consist of boat with size 31-114 GT which can be classified into 3 categories i.e. small(<60 GT), medium (60-150 GT), and large fish trawler (>150 GT). Design and construction of fish trawl net indicated that fish trawl net operates in the Indian Ocean was high opening trawl with head and ground rope of 27.8-41.5 m and 29,7-45.8 m, respectively. Fishing trip generally 10-12 days with effective days 7-9 days per trip and the number of net setting was 5-6 times each day. The fishing grounds of fish trawl based in Sibolga were the coastal waters area with maximum depth of 91 m. At least 40 species of fishes and shrimps identified during research and dominant fish species was ponyfish (Leiognathus spp.) threadfin bream (Nemipterus spp.), tall fin goatfish (Upeneus spp.), seacatfish (Arius sp.) as well as yellow striped goatfish (Upeneus vitattus). The average of catch of fish trawler fleet in the year of 2007 was 249.3 kg/haul and that number seems smaller than average of catch/haul previous years. This situation indicates that decreasing of catch per haul of fish trawlers based in Sibolga continues occurring and in other hand price of fuel raises significantly so that big fish trawlers size 150 GT with engine power more than 600 HP are not able to continue their fishing operation.
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4

Anggawangsa, Regi Fiji, Suwarso Suwarso, and Wudianto Wudianto. "CATCH RATE AND CATCH COMPOSITION OF MINI PURSE SEINE IN BUALEMO, BANGGAI DISTRICT." Indonesian Fisheries Research Journal 20, no. 1 (June 1, 2014): 23. http://dx.doi.org/10.15578/ifrj.20.1.2014.23-28.

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Small pelagic fishery is the largest potential commodity in the waters of Tomini Bay which reached 64% of the total fish resources. Mini purse seine (soma pajeko) is the major fishing gear that used to utilize small pelagic resources in Tomini Bay. One of the main fishing grounds of mini purse seine vessels in Tomini Bay is in Bualemo and the surrounding waters. The aim of this research was to describe mini purse seine fishery in Bualemo especially about the aspects of the catch rate and catch composition. From the analysis of the daily catch data, there was a fluctuation of the average of catch rate each month. The catch of mini purse seine in Bualemo was dominated by two main species that is malalugis/mackerel scad (Decapterus macarellus) and bigeye scad (Selar crumenophthalmus). The large amount of the young fish (juvenile) caught by mini purse seine caused by the vessels operated around FADs and the mesh size that was less selective.
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5

Dauk, Philip C., and Carl J. Schwarz. "Catch Estimation in the Presence of Declining Catch Rate Due to Gear Saturation." Biometrics 57, no. 1 (March 2001): 287–93. http://dx.doi.org/10.1111/j.0006-341x.2001.00287.x.

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6

Xiao, Yongshun. "Catch equations: calculating the instantaneous rate of fishing mortality from catch and back." Ecological Modelling 193, no. 3-4 (March 2006): 225–52. http://dx.doi.org/10.1016/j.ecolmodel.2005.08.034.

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7

Monnahan, Cole C., and Ian J. Stewart. "The effect of hook spacing on longline catch rates: Implications for catch rate standardization." Fisheries Research 198 (February 2018): 150–58. http://dx.doi.org/10.1016/j.fishres.2017.10.004.

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8

Shelton, Peter A. "Did over-reliance on commercial catch rate data precipitate the collapse of northern cod?" ICES Journal of Marine Science 62, no. 6 (January 1, 2005): 1139–49. http://dx.doi.org/10.1016/j.icesjms.2005.04.009.

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Abstract It has been suggested that a number of “lessons” can be learned from the collapse of the northern cod stock off Newfoundland and Labrador. However, not all purported lessons have been validated with available data. One lesson is thought to be that over-reliance on commercial catch rate data and an incorrect assumption regarding the functional relationship between catch rate and population size were major contributors to overestimating stock size, precipitating the collapse. The current study describes calibration approaches used in assessments, and evaluates alternative functional relationships between commercial catch rates and stock size. In addition, historical population size is re-estimated using only research vessel data and compared with estimates obtained based on both commercial catch rate and research vessel data. Calibration with commercial catch rate contributed to overestimating stock size in some years, but there is no evidence that the assumed functional relationship between commercial catch rate and population size was a significant factor in the collapse.
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9

Rijnsdorp, Adriaan D., Jan Jaap Poos, and Floor J. Quirijns. "Spatial dimension and exploitation dynamics of local fishing grounds by fishers targeting several flatfish species." Canadian Journal of Fisheries and Aquatic Sciences 68, no. 6 (June 2011): 1064–76. http://dx.doi.org/10.1139/f2011-032.

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Patch exploitation dynamics, based on individual tow data, provided new insights into the fishing behavior of mixed fisheries. Fishing grounds were determined and their geometry quantified based on the proximity of tow positions. Tows were classified as being part of either searching, sampling, or exploitation behavior based on the intertow distance. Fishers can detect patches of flatfish on a scale of ∼25 nautical miles2. Catch rate during exploitation was 24%–36% above the catch rate while searching, and decreased at a rate of 20%·day–1. Once a patch was found, exploitation occurred until the catch rate dropped below a threshold level. The optimal giving-up catch rate was estimated based on the observed search time, catch rate decline, and range of fishing ground quality. The observed giving-up catch rate was 6%–11% higher than predicted by the marginal value theorem. The discrepancy between the observed and predicted patch leaving decision was consistent with the bias expected in an individual transferable quota (ITQ) management system. Our results provide a basis for interpreting vessel monitoring system (VMS) data and studying the interaction among fishers and between fishers and their resources at the appropriate time and spatial scale.
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10

Jatmiko, Irwan, Bram Setyadji, and Rani Ekawaty. "The Effect of Moon Phase on The Catch of Bigeye Tuna (Thunnus obesus) in Eastern Indian Ocean." ILMU KELAUTAN: Indonesian Journal of Marine Sciences 21, no. 3 (August 30, 2016): 101. http://dx.doi.org/10.14710/ik.ijms.21.3.101-106.

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Tuna is one of the important export commodities to increase government income. One of economically important tuna species is bigeye tuna (Thunnus obesus) which has a proportion of 21% of the total production of large tuna group. The objective of this study was to investigate the effects of different moon phase on the catch of bigeye tuna (T. obesus) in Eastern Indian Ocean. Data collection was conducted by the scientific observers from August 2005 to June 2014 in the tuna longline vessels were based in the port of Benoa, Bali. Moon phase data were collected from August 2005 to June 2014 from National Aeronautics and Space Administration (NASA). Catch data were calculated using the catch rate formula which defined as the number of catches per 100 hooks. The number of catch rate then was sorted into each moon phases and were analyzed using one-way Anova. This study covered 62 trips and 1,480 numbers of operations or sets was conducted from sampled vessels. The result showed that the average catch rate of bigeye tuna differed significantly among the moon phases. Tukey post-hoc tests showed that the average catch rate at full moon was the highest among the groups with around 0.3/100 hooks. This study showed that moon phase had significant effect on the catch of bigeye tuna (T. obesus) that increased the catch during full moon. Keywords: moon phase, catch rate, Eastern Indian Ocea, tuna, Thunnus obesus
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11

Ortega-García, Sofía, Alexander Klett-Traulsen, and German Ponce-Díaz. "Analysis of sportfishing catch rates of striped marlin (Tetrapturus audax) at Cabo San Lucas, Baja California Sur, Mexico, and their relation to sea surface temperature." Marine and Freshwater Research 54, no. 4 (2003): 483. http://dx.doi.org/10.1071/mf01258.

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Cabo San Lucas, Baja California Sur, Mexico, is the main sportfishing location for striped marlin, with a mean annual catch rate of 0.6 fish per fishing trip. In the present study, the interannual and seasonal variation of sportfishing catch rates from 1990 to 1999, and their relationship to mean monthly sea surface temperatures were analysed. Although interannual variation was not significant, the seasonal effect showed significant differences, with highest average catch rates in winter, and lowest catch rates in summer (0.9 and 0.3 respectively). An interannual significant difference with a decreasing tendency was in length analysis. Significant length and weight differences were found between males and females. Among females, the heaviest fish were recorded during spring. A significant relationship between catch rate and sea surface temperature (r = –0.62) was found, but no significant changes of catch rates could be measured during the 1992–1993 and 1997–1998 El Niño Southern Oscillation events, in spite of an apparent catch rate increase during the spring of 1998. Highest catch rates were recorded at between 22 and 24°C.
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12

Ihsan, Yudi Nurul, Nita Ulfah Khoirunisa, Indah Riyantini, Rahman Elfithri, Tri Dewi K. Pribadi, and Siti Nor Aisyah Md Bati. "Comparison of the Catching Results of Mini One-Boat and Two-Boat Purse Seine in Bali Strait, Muncar, East Java Province." Malaysian Journal of Applied Sciences 5, no. 1 (April 30, 2020): 8–14. http://dx.doi.org/10.37231/myjas.2020.5.1.240.

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Mini purse seine has a major contribution in increasing production of small pelagic catches in Pelabuhan Perikanan Pantai (PPP) Muncar, because it has high productivity and the construction made according to catch schooling fish. This research aims to compare the catches composition and catch rate of mini one-boat and two-boat purse seine in Bali Strait, Indonesia. This research was conducted in Mei 2018 in Muncar, East Java, Indonesia. The method used in this research is survey. The primary data are total catch composition, fork length, individual weight of total catch and operation time of both fishing gears. Data were analysed by main catch and bycatch proportion, legal size proportion and catch rate. The results showed that the mini two-boat purse seine had a greater catch volume compared to the mini one-boat purse seine. The bycatch composition dominates in both fishing gear. The proportion of legal-size catching is 67% of the total. The fork length is not significantly different and for the total catches is significantly different. The catching rate of the mini purse seine one boat catch rate is lower at 4,048.67 kg/hour, compared to the mini two-boat purse seine which is 9,189.18 kg/hour.
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13

McGarvey, Richard, André E. Punt, Janet M. Matthews, John E. Feenstra, Caleb Gardner, Paul Burch, Klaas Hartmann, and Adrian Linnane. "Comparing size-limit and quota policies to increase economic yield in a lobster fishery." Canadian Journal of Fisheries and Aquatic Sciences 72, no. 9 (September 2015): 1292–305. http://dx.doi.org/10.1139/cjfas-2014-0405.

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To advance economic and sustainability objectives in a lobster fishery, four broadly different management policies were evaluated: minimum and maximum size limits, constant catch quotas, and quota set yearly in proportion to the previous year’s catch per unit effort (CPUE). The performance of each policy was evaluated based on its discounted economic yield, together with egg production, catch, and catch stability. Maximum size limits performed poorly for all indicators. Raising the minimum size increased economic yield by improving yield-per-recruit. Output controls, both constant and dynamic, uniformly outperformed size limits, leading to substantially higher economic yield and egg production. A dynamic harvest control rule, setting quota in proportion to the previous year’s catch rate, achieved the highest economic yield, catch, and egg production over 20 years. The optimal (30%) exploitation rate under this policy produced a 182% improvement in economic yield compared with a baseline strategy of only minimum size, but led to a mean year-to-year change in quota of 11.5% in response to yearly variable recruitment. This quota-setting management regime is straightforward to implement, using only catch rate as input. When absolute exploitation rate estimates are not available, this quota-setting harvest control rule can be constructed using only a target level of effort.
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14

Marriott, Ross J., Berwin A. Turlach, Kevin Murray, and David V. Fairclough. "Evaluation of spatiotemporal imputations for fishing catch rate standardization." Canadian Journal of Fisheries and Aquatic Sciences 74, no. 9 (September 2017): 1348–61. http://dx.doi.org/10.1139/cjfas-2016-0182.

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As commercial fishing activity shifts to target different grounds over time, spatial gaps can be created in catch rate data, leading to biases in derived indices of fish abundance. Imputation has been shown to reduce such biases. In this study, the relative performance of several imputation methods was assessed using simulated catch rate data sets. Simulations were carried out for three fish stocks targeted by a commercial hook-and-line fishery off the southwestern coast of Australia: snapper (Chrysophrys auratus), West Australian dhufish (Glaucosoma hebraicum), and baldchin groper (Choerodon rubescens). For high-growth scenarios, the mean squared errors (MSEs) of geometric and linear imputations were lower, indicating higher accuracy and precision than that for base method (constant value) imputations. For low-growth scenarios, the lowest MSEs were achieved for base method imputations. However, for the final standardized and imputed abundance indices, the base method index consistently demonstrated the largest biases. Our results demonstrate the importance of selecting an appropriate imputation method when standardizing catch rates from a commercial fishery that has changed its spatial pattern of fishing over time.
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15

McCormick, Joshua L., Michael C. Quist, and Daniel J. Schill. "Effect of Survey Design and Catch Rate Estimation on Total Catch Estimates in Chinook Salmon Fisheries." North American Journal of Fisheries Management 32, no. 6 (December 2012): 1090–101. http://dx.doi.org/10.1080/02755947.2012.716017.

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16

Beardmore, Ben, Len M. Hunt, Wolfgang Haider, Malte Dorow, and Robert Arlinghaus. "Effectively managing angler satisfaction in recreational fisheries requires understanding the fish species and the anglers." Canadian Journal of Fisheries and Aquatic Sciences 72, no. 4 (April 2015): 500–513. http://dx.doi.org/10.1139/cjfas-2014-0177.

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Whenever satisfied anglers are an important objective of recreational fisheries management, understanding how trip outcomes influence satisfaction reports is critical. While anglers, generally, prefer high catch rates and large fish, the relative importance of these catch outcomes for catch satisfaction has not been established across species and angler types. We examined relationships between angler specialization, trip outcomes (both catch and non-catch characteristics such as crowding), and catch satisfaction across six freshwater fish species in northern Germany. As expected, catch satisfaction was primarily determined by catch rate and fish size in all fish species; however, the relative importance of these two outcomes varied considerably across species and among angler types that differed by commitment to fishing. We found a diminishing marginal return of satisfaction for increasing catch rate for all but small-bodied cyprinid species, while increasing size of largest retained fish monotonically increased catch satisfaction in all species we examined. Non-catch outcomes (e.g., the number of other anglers seen while fishing) also had a significant negative influence on catch satisfaction, suggesting that non-catch factors are important in establishing expectations and for contextual evaluation of catch outcomes. We also determined that diversified trips made anglers more satisfied and that all else being equal, specialized anglers increased catch satisfaction from travel and fishing time. The results highlight the importance for managers to consider their particular mix of anglers as well as the fish species present when setting regulations aimed at increasing angler satisfaction.
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17

Bacheler, Nathan M., Zeb H. Schobernd, David J. Berrane, Christina M. Schobernd, Warren A. Mitchell, and Nathan R. Geraldi. "When a trap is not a trap: converging entry and exit rates and their effect on trap saturation of black sea bass (Centropristis striata)." ICES Journal of Marine Science 70, no. 4 (May 27, 2013): 873–82. http://dx.doi.org/10.1093/icesjms/fst062.

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Abstract Bacheler, N. M., Schobernd, Z. H., Berrane, D. J., Schobernd, C. M., Mitchell, W. A., and Geraldi, N. R. 2013. When a trap is not a trap: converging entry and exit rates and their effect on trap saturation of black sea bass (Centropristis striata) – ICES Journal of Marine Science, 70: 873–882. Catch rates are often used to index the abundance of marine organisms, but catch saturation (i.e. declining catch rate as fishing time increases) can decouple catch and abundance. Researchers have struggled to account for saturation when using trap catch to infer population dynamics. We used the underwater video to document entries and exits of black sea bass (Centropristis striata) from chevron traps (n = 26) to quantify catch saturation. Black sea bass catch varied between 3 and 188 individuals for soak times of ∼90 min. Overall, 3564 black sea bass entered the traps and 1826 exited; therefore, over half (51%) of black sea bass entering traps exited before traps were retrieved. Black sea bass catch rates were non-linear and asymptotic for most (81%) trap samples, despite short soak times. Moreover, catch saturation occurred at 50 min, when the entry rate declined and the exit rate increased to a point where their confidence intervals overlapped. Several lines of evidence suggest that the level of black sea bass catch once saturation occurred may be positively related to true abundance, but additional research is needed to more fully test this hypothesis.
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18

Rachman, Faizal, Zaid H. Arrosyid, and Saiful N. Syahrifudin. "Composition and catch rate of fishing pot as eco-friendly fishing gear at the estuary of Bogowonto River in Kulon Progo Regency." E3S Web of Conferences 147 (2020): 02014. http://dx.doi.org/10.1051/e3sconf/202014702014.

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The estuary of Bogowonto river in Kulon Progo Regency was habited by various species such as fish, shells, crabs, and snails. This research aimed to know the composition and catch rate of the fishing pot using various kinds of fodder. The method used in this research was catch identification and assessment of type, length and weight of the catch, and also the fishing pot’s effectiveness as eco-friendly fishing gear. Data analysis was conducted by measuring fish length, catch composition, and catch rate of the fishing pot. The result showed the catch composition consisted of 8 types of species which are mangrove crab (5%), freshwater crab (0.81%), pufferfish (3.38%), orange-spotted grouper fish (0.14%), green tiger prawn (0.14%), giant tiger prawn (0.41%), banana prawn (0.14%) and freshwater snail (90%). The pot with fresh fish fodder had the highest number of catch (66.08%) compare to salted fish (23.51%) and roasted coconut (10.41%) fodder. The highest catch rate of fishing pot was observed on fresh fish fodder (35.42 g/fishing pot) compare to salted fish fodder (11.19 g/fishing pot) and roasted coconut fodder (4.61 g/fishing pot). Based on the result, fresh fish is considered a more effective fodder compared to salted fish and roasted coconut.
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19

Pollock, Kenneth H., John M. Hoenig, Cynthia M. Jones, Douglas S. Robson, and Colin J. Greene. "Catch Rate Estimation for Roving and Access Point Surveys." North American Journal of Fisheries Management 17, no. 1 (February 1997): 11–19. http://dx.doi.org/10.1577/1548-8675(1997)017<0011:crefra>2.3.co;2.

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20

Sarangapani, Krishna K., Jin Qian, Wei Chen, Veronika I. Zarnitsyna, Padmaja Mehta, Tadayuki Yago, Rodger P. McEver, and Cheng Zhu. "Regulation of Catch Bonds by Rate of Force Application." Journal of Biological Chemistry 286, no. 37 (July 20, 2011): 32749–61. http://dx.doi.org/10.1074/jbc.m111.240044.

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21

Budi, Eko Setyo. "The Effect of Bait on The Catch Composition of Square Folding Trap in Rawa Pening Semarang Regency." TROPICAL WETLAND JOURNAL 6, no. 2 (December 7, 2020): 30–37. http://dx.doi.org/10.20527/twj.v6i2.86.

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This study aims to determine the effect of the type of bait on the composition of the catch fish, catch rate, and trap rate using square folding traps. The study was conducted at three fishing locations in October 2019-January 2020 using the experimental fishing method. The operation of square folding traps was done by a total of 60 units. The types of bait used are golden snails, shrimp paste, and trash fish. Fish catches were recorded in number, type, length, and weight, and analyzed using one-way anova test and kruskal wallis test. The composition of the square folding traps catches consists of six species. Marble goby (Oxyeleotris marmorata) is the most dominant catch (60%). The highest catch rate was obtained from box folding traps which were given golden snail bait at 173.50 g/trip, then trash fish bait at 76.88 g/trip and shrimp paste feed at 59.22 g/trip. The highest trap rate is golden snail bait of 12.33%. The bait treatment gives a real difference to the amount and weight of the catch, the golden snail bait gives the highest total number and weight of the catch compared to other baits.
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22

Musim, Musim, M. P. Damanik, and Purnomo Suryantoro. "Effect of urethral meatus cleansing on midstream urine contamination rate in boys." Paediatrica Indonesiana 48, no. 3 (September 26, 2016): 180. http://dx.doi.org/10.14238/pi48.3.2008.180-5.

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Background Clean-catch midstream urine (MSU) remains thestandard procedure for urine collection even if it's role to reducebacterial contamination rate is unclear.Objective To compare bacterial contamination rate betweenclean-catch (cleaning urethral meatus with medicated soap) andnon clean-catch MSU among boys.Methods An experimental study with parallel groups and blockrandomization was conducted. Toilet-trained boys aged 3 to 18years, without symptoms or signs of urinary tract infection wererecruited from the Pediatric Outpatient Clinic at Sardjito Hospitaland from a local elementary school. Subjects with history of renaldisease, those who were on under antibiotic treatment in thepreceding week, or with meatal abnormality or non-cooperativewere excluded. Urine specimen was collected by a trained nurse,and was cultured within one hour by personnel blinded to theassignment. Significant bacteriuria was defined as growth of asingle pathogenic organism (degree of pathogenicity group I-III)with colony count 2: 105 colony forming unit/mi. Contaminationwas defined as any growth not fulfilling criteria for significantbacteriuria or growth of multiple organisms.Results A total of 80 boys were enrolled. The contamination ratein the clean-catch group was 13% (5 out of 40) compared with10% (4 out of 40) in the non clean-catch group (P=l.O). Theadjusted risk ratio for contamination in the clean-catch MSUgroup, adjusted to age and circumcision status, was 1.37 (95%CI 0.42; 4.51).Conclusion Clean-catch method does not reduce bacterial con-tamination rate of midstream urine cultures in boys
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Hall, D. L., R. Hilborn, M. Stocker, and C. J. Walters. "Alternative Harvest Strategies for Pacific Herring (Clupea harengus pallasi)." Canadian Journal of Fisheries and Aquatic Sciences 45, no. 5 (May 1, 1988): 888–97. http://dx.doi.org/10.1139/f88-107.

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A simulated Pacific herring (Clupea harengus pallasi) population is used to evaluate alternative management strategies of constant escapement versus constant harvest rate for a roe herring fishery. The biological parameters of the model are derived from data on the Strait of Georgia herring stock. The management strategies are evaluated using three criteria: average catch, catch variance, and risk. The constant escapement strategy provides highest average catches, but at the expense of increased catch variance. The harvest rate strategy is favored for its reduced variance in catch and only a slight decrease in mean catch relative to the fixed escapement strategy. The analysis is extended to include the effects of persistent recruitment patterns. Stock–recruitment analysis suggests that recruitment deviations are autocorrelated. Correlated deviations may cause bias in regression estimates of stock–recruitment parameters (overestimation of stock productivity) and increase in variation of spawning stock biomass. The latter effect favors the constant escapement strategy, which fully uses persistent positive recruitment fluctuations. Mean catch is depressed for the harvest rate strategy, since the spawning biomass is less often located in the productive region of the stock–recruitment relationship. The model is used to evaluate the current management strategy for Strait of Georgia herring. The strategy of maintaining a minimum spawning biomass reserve combines the safety of the constant escapement strategy and the catch variance reducing features of the harvest rate strategy.
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24

Suhariyanto, Adi, Faizal Rachman, Eko Setyobudi, Riza Yuliratno Setiawan, Nahla Alfiatunnisa, and Supardjo Supardi Djasmani. "Composition and catch rate of folded cube fish pots in the sea of Tuban Regency." E3S Web of Conferences 147 (2020): 02003. http://dx.doi.org/10.1051/e3sconf/202014702003.

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This study aimed to determine the composition and catch rate of folded cube fish pots in the seawater of the Tuban Regency. The research was conducted in December 2018 located in the Sokorejo, Tuban Regency, using 30 units of folded cube fish pots with a size of 50x50x50 cm2. The cube folded trap installation was done in 10 times of catch trip and installed in the morning. The catches were collected, identified, and measured for their individual length and weight. The crabs were measured for the length and width of their carapace. The catching result of folded cube fish pots was classified into five types which are fish group (48.97%), crabs group (29.59 %), swimmer crabs (7.1%), Land hermit crab (6.12%), and mud snails (8.16%). The result showed that Two-spined Arm Swimming Crab (Charybdis anisodon) was the most dominant type of catch equal to 29.59% of the total catch, while other types of catch that were quite common are Pig Faced Leather Jacket (Paramonacanthus choirocephalus) (9.18%), and Crescent Pearch (Terapon jarbua) (8.16%). The average catch rate for folding cube was 32%/trip with a weighted average catch of 436.58 gr/trip.
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25

Zahra, Ageng Nur Agustins, Susiana Susiana, and Dedy Kurniawan. "Potensi lestari dan tingkat pemanfaatan ikan selar (Atule mate) yang didaratkan di Desa Kelong, Kabupaten Bintan, Indonesia." Akuatikisle: Jurnal Akuakultur, Pesisir dan Pulau-Pulau Kecil 3, no. 2 (November 8, 2019): 17. http://dx.doi.org/10.29239/j.akuatikisle.3.2.17-23.

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Yellowtail scad fish was an economic value fish that many fishermen in Kelong Village catch. One of fishing ground in Bintan was Merapas Waters. Fishing activities without considering fish stocks in nature will caused overfishing. The objective of this research was to determine the Maximum Sustainable Yield (MSY), rate and effort of utilization, and Total Allowed Catch (TAC) of Yellowtail Scad fish in Merapas waters landed on Kelong Village. The fishing gear that Fishermen in Kelong Village used to catch Yellowtail Scad fish was hand line. This research used survey method. Primary data from this research were catch and effort of Yellowtail Scad Fish, while secondary data obtained from fishermen interviews and related literature. Data analysis of this research used Schaefer method. The result of this research was the potential value of MSY is 2,501.37 kg/month with the optimum effort (f opt) 178 trip. The utilization rate of Yellowtail Scad fish was 38.48% and effort rate of Yellowtail Scad fish was 22.16%. Total allowed catch value of Yellowtail Scad fish was 2,001.1 kg. Overall, the catch of Yellowtail Scad Fish hasn’t reach overfishing, so the fishing effort can be more optimized.
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Zahra, Ageng Nur Agustins, Susiana Susiana, and Dedy Kurniawan. "Potensi lestari dan tingkat pemanfaatan ikan selar (Atule mate) yang didaratkan di Desa Kelong, Kabupaten Bintan, Indonesia." Akuatikisle: Jurnal Akuakultur, Pesisir dan Pulau-Pulau Kecil 3, no. 2 (November 21, 2019): 57. http://dx.doi.org/10.29239/j.akuatikisle.3.2.57-63.

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Yellowtail scad fish was an economic value fish that many fishermen in Kelong Village catch. One of fishing ground in Bintan was Merapas Waters. Fishing activities without considering fish stocks in nature will caused overfishing. The objective of this research was to determine the Maximum Sustainable Yield (MSY), rate and effort of utilization, and Total Allowed Catch (TAC) of Yellowtail Scad fish in Merapas waters landed on Kelong Village. The fishing gear that Fishermen in Kelong Village used to catch Yellowtail Scad fish was hand line. This research used survey method. Primary data from this research were catch and effort of Yellowtail Scad Fish, while secondary data obtained from fishermen interviews and related literature. Data analysis of this research used Schaefer method. The result of this research was the potential value of MSY is 2,501.37 kg/month with the optimum effort (f opt) 178 trip. The utilization rate of Yellowtail Scad fish was 38.48% and effort rate of Yellowtail Scad fish was 22.16%. Total allowed catch value of Yellowtail Scad fish was 2,001.1 kg. Overall, the catch of Yellowtail Scad Fish hasn’t reach overfishing, so the fishing effort can be more optimized.
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27

de Sousa, Barbara Palha. "Fishery for the deep-water spiny lobster Palinurus delagoae in Mozambique, 1980 to 1999." Marine and Freshwater Research 52, no. 8 (2001): 1535. http://dx.doi.org/10.1071/mf01195.

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Catch and effort data collected from 1980 to 1999 from the commercial trap fishery for Palinurus delagoae off Mozambique are presented.Generalized linear models, using the variables year, month, area, and depth, indicate a marked decline in catch rate with time.Intensive exploitation has led to a rapid decline in catches (102 to 48 tonnes) and catch rates (0.74 to 0.33 kg/trap haul) during the last five years. This decline indicates that the population is sensitive to the high fishing levels (over 200000 trap hauls), particularly since 1993. As these lobsters are generally slow growing and long lived, recovery is expected to take a number of years, provided that fishing stays relatively low. Studies of different size categories show that juvenile catch rate was highest in deep water and during summer after the moult in August to October, whereas the larger adult size category was caught more in shallow water during spring, probably during the mating aggregation. These catch rates reflect an inshore migration of juveniles from deep to shallow water. The decline in catch rate appeared greater amongst the small (juvenile) and medium lobsters because these more abundant categories are more often the target of the fishery.
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28

Hutchings, Jeffrey A., and Mark Ferguson. "Temporal changes in harvesting dynamics of Canadian inshore fisheries for northern Atlantic cod, Gadus morhua." Canadian Journal of Fisheries and Aquatic Sciences 57, no. 4 (April 1, 2000): 805–14. http://dx.doi.org/10.1139/f00-021.

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We quantified temporal changes in catch rate, fishing effort, and catch misreporting for two sectors of the fixed-gear fishery for Newfoundland's northern Atlantic cod, Gadus morhua, from 1980 to 1991, the year preceding the stock's commercial fishing moratorium. Over the 12-year period, fishermen reported catch rate declines of 40 and 75% in the trap and gillnet fisheries, respectively, associated with significant increases in nominal fishing effort. Additional changes to effort included smaller gillnet and trap mesh sizes, larger traps, longer soak times, and modifications to trap design to increase catch retention probabilities. Compared with the early 1980s, unreported catches among inshore fishermen may have trebled by the late 1980s and early 1990s due to longer gillnet soak times, increased gear selectivity for small fish, and declining availability of fish of marketable size. These patterns in harvesting dynamics are consistent with the hypothesis that the decline of northern cod was gradual and that increased rates of catch misreporting contributed to increases in fishing mortality. The concomitants of declining fixed-gear catch rate, increasing quantitative and qualitative fishing effort, increased selectivity for smaller fish, and increasing levels of unreported catches may represent general correlates of imminent fish stock collapses.
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29

Klaer, N. L. "Steam trawl catches from south-eastern Australia from 1918 to 1957: trends in catch rates and species composition." Marine and Freshwater Research 52, no. 4 (2001): 399. http://dx.doi.org/10.1071/mf00101.

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Haul-by-haul steam trawler catch and effort data for 1918–23, 1937–43 and 1952–57, which cover a large portion of the history of steam trawling in the Australian South East Fishery, were examined in detail for the first time. There were 64371 haul records in total. The catch-rate for all retained catch combined shows a strong decline overall, with a brief recovery during World War II, probably due to increased retention of previously discarded species. The fishing fleet moved to more distant fishing grounds and deeper waters as the catch-rate declined. The catch-rates of the main commercial species followed a similar pattern in a number of regions within the fishery. The catch-rate of the primary target species – tiger flathead (Neoplatycephalus richardsoni) – dropped considerably from the early, very high, catch-rates. Chinaman leatherjacket (Nelusetta ayraudi) and latchet (Pterygotrigla polyommata) – species that were apparently abundant in the early years of the fishery, virtually disappeared from catches in later years. The appearance of greater catches of jackass morwong (Nemadactylus macropterus), redfish (Centroberyx affinis) and shark/skate during the war and afterwards was probably due to increased retention of catches of these species. The disappearance of certain species from the catch may be due to high fishing pressure alone, or to a combination of fishing pressure, changes in the shelf habitat possibly caused by the trawl gear, and environmental fluctuations.
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30

Carvalho, Felipe C., Debra J. Murie, Fábio H. V. Hazin, Humberto G. Hazin, Bruno Leite-Mourato, and George H. Burgess. "Spatial predictions of blue shark (Prionace glauca) catch rate and catch probability of juveniles in the Southwest Atlantic." ICES Journal of Marine Science 68, no. 5 (May 1, 2011): 890–900. http://dx.doi.org/10.1093/icesjms/fsr047.

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Abstract Carvalho, F. C., Murie, D. J., Hazin, F. H. V., Hazin, H. G., Leite-Mourato, B., and Burgess, G. H. 2011. Spatial predictions of blue shark (Prionace glauca) catch rate and catch probability of juveniles in the Southwest Atlantic. – ICES Journal of Marine Science, 68: 890–900. Generalized regression analysis and spatial prediction was applied to catch per unit effort (cpue) data for blue shark (Prionace glauca) caught by the Brazilian tuna longline fleet between 1997 and 2008 (43 546 longline sets) to predict the effect of environmental, spatial, and temporal factors on catch distribution. In addition, the size distribution of blue sharks measured by on-board observers during the years 2006–2008 was used to model the proportion of juvenile blue sharks in the catches from a spatial perspective. Latitude was the most important factor influencing blue shark cpue in the Southwest Atlantic, with cpue spatial predictions suggesting two areas of higher catch probabilities. Latitude was also the most important factor influencing the proportion of juveniles in the catches. The spatial prediction map showed that juveniles were more frequently caught south of 35°S (∼38°S). This information can assist in the design of management strategies either to exploit this predictable spatial distribution of the catch or to manage the fisheries in a spatially explicit manner if one component (i.e. juveniles) requires protective measures.
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31

Courtney, Anthony J., Matthew J. Campbell, Darren P. Roy, Mark L. Tonks, Keith E. Chilcott, and Peter M. Kyne. "Round scallops and square meshes: a comparison of four codend types on the catch rates of target species and by-catch in the Queensland (Australia) saucer scallop (Amusium balloti) trawl fishery." Marine and Freshwater Research 59, no. 10 (2008): 849. http://dx.doi.org/10.1071/mf08073.

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Concern over the amount of by-catch from benthic trawl fisheries and research into the problem have increased in recent years. The present paper demonstrated that by-catch rates in the Queensland (Australia) saucer scallop (Amusium balloti) trawl fishery can be reduced by 77% (by weight) using nets fitted with a turtle excluder device (TED) and a square-mesh codend, compared with a standard diamond-mesh codend with no TED. This large reduction was achieved with no significant effect on the legal size scallop catch rate and 39% fewer undersize scallops were caught. In total, 382 taxa were recorded in the by-catch, which was dominated by sponges, portunid crabs, small demersal and benthic fish (e.g. leatherjackets, stingerfish, bearded ghouls, nemipterids, longspine emperors, lizard fish, triggerfish, flounders and rabbitfish), elasmobranchs (e.g. mainly rays) and invertebrates (e.g. sea stars, sea urchins, sea cucumbers and bivalve molluscs). Extremely high reductions in catch rate (i.e. ≥85%) were demonstrated for several by-catch species owing to the square-mesh codend. Square-mesh codends show potential as a means of greatly reducing by-catch and lowering the incidental capture and mortality of undersize scallops and Moreton Bay bugs (Thenus australiensis) in this fishery.
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32

Balcombe, Stephen R., and Gerard P. Gloss. "Variation in Carp Gudgeon (Hypseleotrisspp.) Catch Rate in Dense Macrophytes." Journal of Freshwater Ecology 15, no. 3 (September 2000): 389–95. http://dx.doi.org/10.1080/02705060.2000.9663757.

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33

Al-Baz, A., J. M. Bishop, M. Al-Husaini, and W. Chen. "Gargoor trap fishery in Kuwait, catch rate and species composition." Journal of Applied Ichthyology 34, no. 4 (April 23, 2018): 867–77. http://dx.doi.org/10.1111/jai.13703.

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34

Matsuda, Hiroyuki, Tatsu Kishida, and Takashi Kidachi. "Optimal Harvesting Policy for Chub Mackerel (Scomber japonicus) in Japan under a Fluctuating Environment." Canadian Journal of Fisheries and Aquatic Sciences 49, no. 9 (September 1, 1992): 1796–800. http://dx.doi.org/10.1139/f92-199.

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Temporal fluctuation in the reproduction rates of chub mackerel (Scomber japonicus) was estimated for the period 1971–86, when stock abundance of chub mackerel varied from a high to low level. To estimate the effect of various harvesting policies on stock conservation and the long-term catch, six harvesting policies were considered: (1) actual catch data during 1975–88, (2) 1/3 constant rate of exploitation, (3) low maximal catch amount, (4) 1/5 constant rate of exploitation, (5) prohibition of fishing when the stock is rare, and (6) constant-escapement policy. Using the data of reproduction rates during 1975–85, the final stock abundance at 1988 and the total catch amount during 1975–88 under each harvesting policy are calculated. We concluded that harvesting policies (4), (5), and (6) were effective for the stock conservation and that policies (2), (5), and (6) were effective for increasing the total catch.
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35

Sinanoglu, Orhun, Seyit Erkan Eyyupoglu, and Sinan Ekici. "Ipsilateral Testicular Catch-Up Growth Rate Following Microsurgical Inguinal Adolescent Varicocelectomy." Scientific World Journal 2012 (2012): 1–4. http://dx.doi.org/10.1100/2012/356374.

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Objective. To evaluate the ipsilateral catch-up growth rates compared to contralateral testicular growth in adolescents with varicocele undergoing microsurgical inguinal varicocelectomy.Materials and Methods. Between December 2005 and May 2007, 39 adolescent patients with grade 2-3 varicocele admitted to our clinic with complaints of pain and/or testicular asymmetry were operated. Preoperative mean age was 14.5 ± 1.96 (9–17). Testicular volumes were assessed with ultrasound every 3 months. The available followup was 39 months.Results. In our series, mean testicular preoperative volumes were9.07±3.19 mL for the right and5.90±1.74 mL for the left. Mean testicular volumes at the end of follow up were13.97±3.42 mL for the right and12.20±4.05 mL for the left. The testicular catch-up growth approximately begins after the 9th month and significant catch-up occurred in the 12–24 months (P<0.05).Conclusion. Since testicular volume is the primary method of assessing testicular function in adolescents, testicular size can predict future fertility status significantly 9 months after surgical varicocele correction.
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36

Punt, André E., and Robert B. Kennedy. "Population modelling of Tasmanian rock lobster, Jasus edwardsii, resources." Marine and Freshwater Research 48, no. 8 (1997): 967. http://dx.doi.org/10.1071/mf97070.

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From 1980 to 1995, annual catch rates of southern rock lobster (Jasus edwardsii) in Tasmanian waters declined from 1·6 to 0·9 kg per pot lift. From March 1998, the Tasmanian government intends to base management of this fishery on output controls using individual transferable catch quotas. This has necessitated the development of a stock assessment model that can be used to evaluate the relative merits of a variety of alternative catch limits in terms of the trade-off between protecting the rock lobster resource and achieving a high yield. Each of eight regions around Tasmania is assessed separately because of spatial heterogeneity between regions in lobster growth, size at maturity and catch rates. The stock assessment model is size-structured and is fitted to catch, effort and length–frequency data as well as to estimates of exploitation rate from experimental data. A Bayesian estimation framework is employed to estimate the quantities needed for risk analysis. Egg production differs markedly among the eight regions: from as low as 6% of the unexploited equilibrium level in the northern regions, where the growth rate is fast, to more than 80% in the south-west, where the growth rate is slowest.
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37

Dong, Li, Mari Nygård, and Bo T. Hansen. "Sociodemographic Correlates of Human Papillomavirus Vaccine Uptake: Opportunistic and Catch-Up Vaccination in Norway." Cancers 13, no. 14 (July 12, 2021): 3483. http://dx.doi.org/10.3390/cancers13143483.

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Achieving equity in human papillomavirus (HPV) vaccination has high priority. In this nationwide registry-based study, we aimed to investigate sociodemographic correlates of HPV vaccine uptake among women who were vaccinated opportunistically at their own initiative and cost during October 2006–June 2018, and among women who were vaccinated free-of-charge in a catch-up vaccination program during November 2016–June 2018. For 840,328 female residents born in Norway between 1975 and 1996, we retrieved HPV vaccination and sociodemographic data from national registries. We used separate models to analyze the sociodemographic correlates of the initiation and completion of HPV vaccination in opportunistic and catch-up vaccination settings. Overall initiation rate for opportunistic HPV vaccination was 2.2%. Uptake increased consistently with birth year, maternal education level, and household income. Having two immigrant parents or a mother working in a lower prestige occupation was strongly associated with low opportunistic vaccination uptake. Similar but weaker inequities were observed in catch-up HPV vaccination. Initiation rate during the first 20 months of the catch-up program was 46.2%. Completion rate was 72.1% and 73.0% for opportunistic or catch-up vaccination, respectively, with small inequities. In conclusion, HPV vaccine uptake was strongly associated with sociodemographic background both in opportunistic and catch-up vaccination settings, with particularly low uptake associated with having two immigrant parents and low household income.
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38

Gravenhof, Dylan A., Michael E. Barnes, and Robert Hanten. "Escapement of Broodstock Chinook Salmon From Whitlock Bay Spawning Station, Lake Oahe, South Dakota." Aquatic Science and Technology 9, no. 1 (October 20, 2020): 18. http://dx.doi.org/10.5296/ast.v9i1.17330.

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Feral spawning fall Chinook salmon (Oncorhynchus tshawytscha) in Lake Oahe, South Dakota, are captured using a fish ladder and catch raceway at Whitlock Bay Spawning Station. The number of salmon that escaped the catch raceway and descended the fish ladder prior to spawning was unknown. During October 2017, all salmon that ascended the fish ladder at the spawning station were tagged. Tagged males remained in the catch raceway. Tagged females were moved to other secure raceways and used to estimate tag retention. Of the 383 tagged males, 159 (41.5%) were initially designated as escaped from the catch raceway. Tag loss in the females was 3.9%. Thus, the estimated male salmon escapement rate from the catch raceway was 37.6%. Male salmon remained in the catch raceway for one-to-three days before escaping. The escapement rate decreased over the month-long spawn, with nearly 60% of the males going back down the fish ladder in the first week of October, compared to less than 20% escapement by the final week. Such high rates of escapement from the spawning station may be negatively impacting the spawning efficiencies. Possible solutions include re-engineering of the fish ladder or daily removal of the salmon in the catch raceway to other more secure locations at the spawning station.
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39

Dudley, Sheldon F. J., and Colin A. Simpfendorfer. "Population status of 14 shark species caught in the protective gillnets off KwaZulu - Natal beaches, South Africa, 1978 - 2003." Marine and Freshwater Research 57, no. 2 (2006): 225. http://dx.doi.org/10.1071/mf05156.

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Shark nets have been set off the beaches of KwaZulu–Natal, South Africa, since 1952 to reduce the risk of shark attack. The nets fish in fixed localities 400 m from shore and both directly affect local shark populations and act as fisheries-independent monitoring devices. Reliable catch information at the species level was available for the period 1978–2003. Trends in catch rate and size were used to assess the population status of 14 commonly caught shark species. In addition, a demographic modelling approach was used in conjunction with the catch information to assess the potential effect of the nets on populations. Catch rates of four species (Carcharhinus leucas, C. limbatus, Sphyrna lewini and S. mokarran) showed a significant decline, as did the mean or median length of three species (Carcharhinus amboinensis, C. limbatus and female Carcharodon carcharias). For three species that showed declining catch rates or length the potential effect of the shark nets was assessed to be low, suggesting that other sources of catch were responsible for the declining status. The potential effect of the shark nets was assessed to be high for two species (Carcharhinus obscurus and Carcharias taurus, neither of which showed declines in catch rate or length), because of very low intrinsic rates of population increase.
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40

Dewanti, Lantun Paradhita, Izza Mahdiana, Irfan Zidni, and Heti Herawati. "EVALUASI SELEKTIVITAS DAN KERAMAHAN LINGKUNGAN ALAT TANGKAP DOGOL DI KABUPATEN PANGANDARAN PROVINSI JAWA BARAT." Jurnal Airaha 7, no. 01 (June 25, 2018): 030–37. http://dx.doi.org/10.15578/ja.v7i01.84.

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The purpose of this study was to determine the selectivity and level of environmental friendliness of mini bottom trawl in Pangandaran District. This research conducted on May-October 2017. Primary data obtained from purposive sampling either by interview or observation Selectivity indicator used was selectivity of catch species and size. Environmental friendly fishing was evaluated based on the FAO criteria. The result showed that catch rate of mini bottom trawl was 26.45 kg/hour. The main catch of mini bottom trawl in Pangandaran District was Trachypenaeus asper amount of 39,5% while by catch was Acetes sp¸ Oiolithes ruber, Trichiurus lepturus, and others catch with amount 60,40%. Catch size of mini bottom trawl main catch was ranged 4 cm - 9.90 cm. The main catch was 39,00% was more than size capture and under size capture was 61.00%. Catch utilization of this fishing gear was 93%. The result evaluation of environmental friendliness based on catch selectivity was 6 point which mean ‘less environmentally’ friendly while FAO criteria showed 18 point which mean ‘not environmentally’ friendly fishing.
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41

Suwarso, Suwarso, Arief Wujdi, and Moh Fauzi. "EXPLOITATION AND CATCH FLUCTUATION OF SMALL PELAGIC FISHES IN PRIGI WATERS, SOUTH COAST OF JAVA." Indonesian Fisheries Research Journal 20, no. 2 (December 1, 2014): 69. http://dx.doi.org/10.15578/ifrj.20.2.2014.69-76.

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Studies on the exploitation and catch fluctuations of pelagic fishes have been undertaken in order to understand the fishery systems, annual and seasonal change of fishing effort and catches, as well as species composition. The study was based on the daily monitoring data of the purse seiners. The results showed that generally the fishing activities is one day fishing, the increase of fishing effort reflected in the number of fishing units and the number of trip, while the trend of production and catch rate were fluctuated by either annual or seasonal; the peak of catch rate was occurred in 2007, 2008 and 2012 periods, during December to June were low catches, and are going in the peak season in September-October. The lowest catch rate is about 100kg/trip and the maximum of 4.3 tons/trip (the average of 1.3 tons/trip), however the fail of fishing was often occurs and reached 30% of the total number of trips; the failed fishing was decline from year to year. The catch rate (kg/trip/day) was showed a pattern fluctuations; the small pelagic fish mainly the scads (Decapterus spp.) and clupeids (Bali sardine, Sardinella lemuru), respectively 33% and17%, whereas the dominan large pelagic fish is ‘tongkol’/frigate tuna (Auxis thazzard). The changes of species domination was occurred either in annually or seasonally.
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42

Polacheck, Tom, J. Paige Eveson, Geoff M. Laslett, Kenneth H. Pollock, and William S. Hearn. "Integrating catch-at-age and multiyear tagging data: a combined Brownie and Petersen estimation approach in a fishery context." Canadian Journal of Fisheries and Aquatic Sciences 63, no. 3 (March 1, 2006): 534–48. http://dx.doi.org/10.1139/f05-232.

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A comprehensive framework for modelling data from multiyear tagging experiments in a fishery context is presented that incorporates catch data into the traditional Brownie tag–recapture model. Incorporation of catch data not only allows for improved estimation of natural and fishing mortality rates, but also for direct estimation of population size at the time of tagging. These are the primary quantities required to be estimated in stock assessments — having an approach for directly estimating them that does not require catch rates provides a potentially powerful alternative for augmenting traditional stock assessment methods. Simulations are used to demonstrate the value of directly incorporating catch data in the model. Results from the range of scenarios considered suggest that in addition to providing a precise estimate of population size (coefficients of variation ranging from ~15% to 30%), including catch data can decrease biases in the mortality rate estimates (natural mortality especially) and improve precision of fishing mortality rate estimates (by as much as 60% at age 1). The model is applied to southern bluefin tuna (Thunnus maccoyii) tag–recapture and catch data collected in the 1990s to provide estimates of natural mortality, fishing mortality, and abundance for five cohorts of fish.
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43

Campana, Steven E., Linda Marks, Warren Joyce, and Nancy E. Kohler. "Effects of recreational and commercial fishing on blue sharks (Prionace glauca) in Atlantic Canada, with inferences on the North Atlantic population." Canadian Journal of Fisheries and Aquatic Sciences 63, no. 3 (March 1, 2006): 670–82. http://dx.doi.org/10.1139/f05-251.

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The nominal catch of blue sharks (Prionace glauca) reported for the Canadian Atlantic grossly underestimates the annual catch mortality of about 1000 tonnes (t), making blue sharks the most frequently caught large shark in Canadian waters. Although blue sharks accounted for 99% of all sharks landed at recreational shark fishing tournaments, tournament catches accounted for only 3% of total fishing mortality. Standardized catch rate indices suggested a decline in blue shark abundance of about 5%–6%·year–1 since 1995. An increased mortality rate in recent years was suggested by a decline in the median size of blue sharks in the commercial catch. Two independent calculations suggest that North Atlantic catches exceeded 100 000 t, with catch mortalities ranging between 26 000 and 37 000 t. Because tagging studies indicated that blue sharks are highly migratory with a single population in the North Atlantic, the Canadian contribution to overall population mortality accounts for only 2% of the total. The fact that blue shark populations are relatively productive and resilient may help explain their persistence in the face of high international catch mortality and a decline in relative abundance.
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44

Welch, Harold E., John K. Jorgenson, and Martin F. Curtis. "Measuring Abundance of Emerging Chironomidae (Diptera): Experiments on Trap Size and Design, Set Duration, and Transparency." Canadian Journal of Fisheries and Aquatic Sciences 45, no. 4 (April 1, 1988): 738–41. http://dx.doi.org/10.1139/f88-089.

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Experiments at Saqvaqjuac, N.W.T. (63°39′N) showed that submerged funnel traps (0.283 m2) had equal catch rates at 10–12 °C, independent of emptying interval between 1 and 6 d. Inverted funnels in the trap jars reduced the loss of active pupae, and probably sinking dead insects. Catch rates were independent of trap size (0.071–0.283 m2) at emergence densities [Formula: see text]. Preserving-type traps which retained the catch had the same daily catch rate as regular traps when left in place up to 18 d, but none of the preservatives tried was satisfactory and decay was a problem. Catch rates for clear and opaque traps were similar.
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45

Marriott, Ross J., Michael F. O'Neill, Stephen J. Newman, and Craig L. Skepper. "Abundance indices for long-lived tropical snappers: estimating standardized catch rates from spatially and temporally coarse logbook data." ICES Journal of Marine Science 71, no. 3 (October 8, 2013): 618–27. http://dx.doi.org/10.1093/icesjms/fst167.

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Abstract The Northern Demersal Scalefish Fishery has historically comprised a small fleet (≤10 vessels year−1) operating over a relatively large area off the northwest coast of Australia. This multispecies fishery primarily harvests two species of snapper: goldband snapper, Pristipomoides multidens and red emperor, Lutjanus sebae. A key input to age-structured assessments of these stocks has been the annual time-series of the catch rate. We used an approach that combined Generalized Linear Models, spatio-temporal imputation, and computer-intensive methods to standardize the fishery catch rates and report uncertainty in the indices. These analyses, which represent one of the first attempts to standardize fish trap catch rates, were also augmented to gain additional insights into the effects of targeting, historical effort creep, and spatio-temporal resolution of catch and effort data on trap fishery dynamics. Results from monthly reported catches (i.e. 1993 on) were compared with those reported daily from more recently (i.e. 2008 on) enhanced catch and effort logbooks. Model effects of catches of one species on the catch rates of another became more conspicuous when the daily data were analysed and produced estimates with greater precision. The rate of putative effort creep estimated for standardized catch rates was much lower than estimated for nominal catch rates. These results therefore demonstrate how important additional insights into fishery and fish population dynamics can be elucidated from such “pre-assessment” analyses.
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46

Thompson, Grant G. "Confounding of Gear Selectivity and the Natural Mortality Rate in Cases where the Former is a Nonmonotone Function of Age." Canadian Journal of Fisheries and Aquatic Sciences 51, no. 12 (December 1, 1994): 2654–64. http://dx.doi.org/10.1139/f94-265.

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An "exponential–logistic" selectivity function is presented in which a single parameter (γ) determines whether gear selectivity is asymptotic (γ = 0) or reaches a maximum at finite age (γ > 0). The function is used to develop a model in which both γ and the natural mortality rate M are formally indeterminate and in which the coming year's catch limit can be viewed as a response function of either estimated γ or estimated M. Decision theory is then used to derive the optimal catch. The optimal catch is shown to increase with the degree of uncertainty surrounding M, although this conclusion may depend on the short managerial time frame assumed. Three "suboptimal" strategies are also considered: (1) setting catch at the level corresponding to the expected value of M, (2) setting catch at the minimum of the response function, and (3) setting catch at the level corresponding to γ = 0. The first suboptimal strategy never results in a catch greater than the optimum and always results in a lower expected loss than the second. The performance of the third strategy (relative to the others) depends on parameter values.
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47

Walters, Carl. "Folly and fantasy in the analysis of spatial catch rate data." Canadian Journal of Fisheries and Aquatic Sciences 60, no. 12 (December 1, 2003): 1433–36. http://dx.doi.org/10.1139/f03-152.

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Spatial catch per effort data can provide useful indices of population trends provided that they are averaged so as to correct for effects of changes in the distribution of fishing activity. Simple, nonspatial ratio estimates should not be used in such analyses. The averaging for any time period must necessarily make some assumptions about what catch rates would have been in spatial strata that had not yet, or were no longer, being fished. Ignoring the unfished strata (averaging only over the areas that were fished) amounts to assuming that they behaved the same as the fished strata and can lead to severe hyperdepletion in abundance indices for fisheries that developed progressively over large regions.
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48

Marino, Rose, Anita Hegde, Kevin M. Barnes, Lenneke Schrier, Joyce A. Emons, Ola Nilsson, and Jeffrey Baron. "Catch-Up Growth after Hypothyroidism Is Caused by Delayed Growth Plate Senescence." Endocrinology 149, no. 4 (January 3, 2008): 1820–28. http://dx.doi.org/10.1210/en.2007-0993.

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Catch-up growth is defined as a linear growth rate greater than expected for age after a period of growth inhibition. We hypothesized that catch-up growth occurs because growth-inhibiting conditions conserve the limited proliferative capacity of growth plate chondrocytes, thus slowing the normal process of growth plate senescence. When the growth-inhibiting condition resolves, the growth plates are less senescent and therefore grow more rapidly than normal for age. To test this hypothesis, we administered propylthiouracil to newborn rats for 8 wk to induce hypothyroidism and then stopped the propylthiouracil to allow catch-up growth. In untreated controls, the growth plates underwent progressive, senescent changes in multiple functional and structural characteristics. We also identified genes that showed large changes in mRNA expression in growth plate and used these changes as molecular markers of senescence. In treated animals, after stopping propylthiouracil, these functional, structural, and molecular senescent changes were delayed, compared with controls. This delayed senescence included a delayed decline in longitudinal growth rate, resulting in catch-up growth. The findings demonstrate that growth inhibition due to hypothyroidism slows the developmental program of growth plate senescence, including the normal decline in the rate of longitudinal bone growth, thus accounting for catch-up growth.
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49

Maxwell, Michael R., Larry D. Jacobson, and Ramon J. Conser. "Eggs-per-recruit model for management of the California market squid (Loligo opalescens) fishery." Canadian Journal of Fisheries and Aquatic Sciences 62, no. 7 (July 1, 2005): 1640–50. http://dx.doi.org/10.1139/f05-037.

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We develop a per-recruit model for the management of the California market squid (Loligo opalescens) fishery. Based on recent confirmation of determinate fecundity in this species, we describe how catch fecundity (i.e., eggs remaining in the reproductive tracts of harvested females) can be used to simultaneously infer fishing mortality rate along with management reference points such as yield-per-recruit, spawned eggs-per-recruit, and proportional egg escapement. Rates of mortality and egg laying have important effects on these reference points. Somewhat surprisingly, increasing the rate of natural mortality decreased spawned eggs-per-recruit while increasing proportional egg escapement. Increasing the rate of egg laying increased both spawned eggs-per-recruit and egg escapement. Other parameters, such as the maturation rate and gear vulnerability of immature females, affected the reference points. In actual practice, the influence of these parameters for immature squid may go undetected if immature squid are excluded from analysis of the catch. Application of this model to routine management is feasible but requires refinement of sampling procedures, biological assumptions, and model parameters. This model is useful because it is grounded on empirical data collected relatively inexpensively from catch samples (catch fecundity) while allowing for the simultaneous calculation of instantaneous fishing mortality rate and egg escapement.
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50

Zhiqiang, Pei, Lu Shuchang, Wang Xi, Hou Kun, Ya Zongjie, Zhang Yu, Wang Dafeng, and Li Xiawen. "Study on greenhouse soil nitrogen absorption and soil layer transport of different summer catch crops with different planting density in North China." E3S Web of Conferences 143 (2020): 02023. http://dx.doi.org/10.1051/e3sconf/202014302023.

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In order to improve the utilization rate of nitrogen fertilizer and reduce the environmental pollution risk of the nitrogen accumulation in the vegetable field, this study was carried out in the summer leisure period of the greenhouse vegetable production. This experiment designed different planting density treatments in 2017 and 2018, i.e. for catch waxy corn, 3300 plants/667m2 (WCD1), 5000 plants/667m2 (WCD2), 6600 plants/667m2 (WCD3), for forage sweet sorghum, 4500 plants /667m2 (FSS4), 7000 plants/667m2 (FSS5), 9000 plants/667m2 (FSS6) in 2017; and for catch waxy corn, 4500 plants/667m2 (WCDI), 7000 plants/667m2 (WCDII), 9000 plants/667m2(WCDIII), for forage sweet sorghum, 7000 plants/667m2 (FSSIV), 10000 plants/667m2 (FSSV), 14000 plants/667m2 (FSSVI) in 2018. The results showed that the biomass and nitrogen absorption of the two catch crops began to improve and then decreased with the increase of planting density. The nitrogen absorption amount of the catch waxy corn and forage sweet sorghum was 22.36~28.68 kg/667m2,21.67~24.39 kg/667m2, respectively. Different planting density of catch waxy corn and forage sweet sorghum could significantly reduce the total nitrogen content of 0~30cm soil layer and the nitrate nitrogen content of 0~90cm soil layer, for catch waxy corn and forage sweet sorghum, the reduction rate of total nitrogen content in 0~30cm soil layer was 9.6%~27.0%, 5.7%~23.5%, the reduction rate of nitrate nitrogen content reached 50.0%~90.8%, 80.1%~96.4%, respectively, which effectively controlled the nitrate nitrogen leaching to soil deep layer. Planting catch crops could increase soil urease activity, regulate soil nitrogen transformation. Compared with other treatments, WCDII and FSSV treatment can reduce the initial urease activity and soil nitrate nitrogen content of next crops, which is consistent with the nutrient requirements of broccoli in the early stage of growth. These catch crops planting could reduce the nitrogen environmental risk in the greenhouse soil. Finally, the study proposed that the suitable planting density of catch waxy corn and forage sweet sorghum planted was 6600~7000 plants/667m2, and 9000~10000 plants/667m2, respectively, in the greenhouse summer leisure period. It is more advantageous to improve soil nitrogen absorption and reduce soil nitrogen environmental risks for catch waxy corn.
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