Estimation of Recruitment and Natural Mortality Rate from Age-Composition and Catch Data in British Columbia Herring Populations

1955 ◽  
Vol 12 (5) ◽  
pp. 649-681 ◽  
Author(s):  
Albert L. Tester
Keyword(s):  
Mortality Rate ◽  
Age Groups ◽  
Total Mortality ◽  
Vancouver Island ◽  
Island Population ◽  
Natural Mortality ◽  
Age Composition ◽  
Catch Data ◽  
Population Average ◽  
Stable Conditions

If absolute recruitment (R) and natural mortality rate (q) are both presumed constant in each of two or more periods of stabilized fishing, it is shown that i = q + (1/R)iC, where i is instantaneous total mortality rate and C is catch in numbers. The relationship yields approximate estimates of R and q under semi-stable conditions if "average referable C" is related to apparent i, the former derived from catch data and the latter from age-composition data for post-recruited age-groups. In the herring population, in which recruitment takes place mostly at age III but is spread from ages I to IV, the average of the catch of years x and x + 1 is referable to apparent i at ages IV to V in year x + 2, at ages V to VI in year x + 3, etc. When q increases with advancing age, it is shown that R is most accurately estimated from data for ages IV to V; q is slightly overestimated at ages IV to V and underestimated at ages VI to VII and VII to VIII. From data for periods of approximate stability in the lower east coast of Vancouver Island population, average R is estimated at about 500 million fish per year; average q appears to increase with age, ranging from about 0.4 at ages IV to V to about 0.85 at ages VII to VIII. For a recent period of stabilized intensive fishing, a rough estimate of the average initial size of the fishable stock, based on age-composition and catch data, agrees well with that estimated by another method. For populations along the west coast of Vancouver Island, q also appears to increase with advancing age; R is estimated at about 400 million fish. In an appendix it is shown that a method of estimating q from age-composition and effort data gives unsatisfactory results because effort expended in herring fishing is not proportional to rate of fishing of the stock.

Less known aspects of Penaeus kerathurus (Forskål, 1775) (Decapoda, Penaeidae) obtained from the fishermen in the Sea of Marmara: age, growth, and mortality rates

Crustaceana ◽  
2020 ◽  
Vol 93 (9-10) ◽  
pp. 1185-1195
Author(s):  
M. Arslan İhsanoğlu
Keyword(s):  
Growth Parameters ◽  
Economic Value ◽  
Age Groups ◽  
Length Distribution ◽  
Total Mortality ◽  
Mortality Rates ◽  
Natural Mortality ◽  
Sea Of Marmara ◽  
Age Composition ◽  
Important Species

Abstract Penaeus kerathurus is an important species for the fishery, thanks to its high nutritional and economic value. Therefore, this study attempts to determine the length distribution, length-weight relationship, age composition, growth parameters, and mortality rates of a population of P. kerathurus. The material was monthly collected from commercial fishermen in and around Karabiga and the Gulf of Erdek in the Sea of Marmara, between May 2018 and April 2019. The carapace length-weight relationships were calculated as W = 0.0023 × CL2.57, W = 0.0036 × CL2.46, and W = 0.0026 × CL2.56 for the females, males and both sexes combined, respectively. The population studied was distinguished into four age groups, and the tmax (= maximum theoretical age) was found to be reached at 11.9 year. The growth parameters were observed to be  = 60.9 mm; K = 0.24 year−1, and t0 = −0.58 year. The rates of total mortality (Z), natural mortality (M), fisheries mortality (F), and exploitation (E) were calculated to be 1.32, 0.43, 0.89, and 0.67, respectively. The results showed that P. kerathurus suffers from a heavy fishing pressure in the sampled area.

scholarly journals POPULATION DYNAMICS OF TUNA (EUTHYNNUS AFFINIS, CANTOR 1849) IN WESTERN WATERS OF SOUTH SULAWESI

2020 ◽  
Vol 8 (8) ◽  
pp. 164-172
Author(s):  
Budiman Yunus ◽  
Suwarni ◽  
Basse Siang Parawansa
Keyword(s):  
Population Dynamics ◽  
Mortality Rate ◽  
Age Groups ◽  
Total Mortality ◽  
Assessment Tools ◽  
Natural Mortality ◽  
Age Group ◽  
Fishing Mortality ◽  
Growth Coefficient ◽  
South Sulawesi

This study aims to determine the population dynamics of tuna including age group, growth, mortality, exploitation rate and yield per recruitment. It was conducted from June to August in West Waters of South Sulawesi. By method of age group using Bhattacharya method with FAO-ICLARM Fish Stock Assessment Tools II (FISAT II) program, growth using Von Bertalanffy’s equation, natural mortality (M) using Pauly’s empirical equation, total mortality (Z) using Beverton and Holt’s equations, fishing mortality (F) by the formula Z = F + M, exploitation (E) using Baverton and Holt’s equations and yield per recruitment (Y/R’) using Baverton and Holt’s equations. The results of research of tuna observed were 737 includes 355 male tunas and 382 female tunas. The estimation of total length ranging from 215 mm to 429 mm. Male tunas are classified into 4 (four) of age groups with a length of 236.67, 272.8, 326.04 and 375.53 mm, respectively. Asymptote length (L∞) = 455.00 mm, growth coefficient (K) = 0.33 and theoretical age (t0) of -0.2377 per year. Total mortality rate (Z) = 1.12 per year. Natural mortality (M) = 0.41 per year, fishing mortality (F) = 0.71, exploitation (E) = 0.63 and yield per recruitment (Y/R’) = 0.0691, while male tunas are classified into 5 (five) of age groups with a length of 235.73, 272.86, 326.89, 360.89 and 408.89 mm, respectively. Asymptote length (L∞) = 453.50 mm, growth coefficient (K) = 0.42 and theoretical age (t0) of -0.1853 per year. Total mortality rate (Z) = 1.35 per year. Natural mortality (M) = 0.48 per year, fishing mortality (F) = 0.87, exploitation (E) = 0.64 and yield per recruitment (Y/R’) = 0.0784. Thus, it can be concluded that tuna in West Waters of South Sulawesi have declined and thought occur overfishing.

scholarly journals POPULATION DYNAMICS OF MALAYAN LEAF FISH (Pristolepisgrooti Blkr.) IN RANAU LAKE, SOUTH SUMATRA

2018 ◽  
Vol 24 (2) ◽  
pp. 125
Author(s):  
Sevi Sawetri ◽  
Subagdja Subagdja ◽  
Dina Muthmainnah
Keyword(s):  
Mortality Rate ◽  
Growth Parameters ◽  
Total Mortality ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Frequency Data ◽  
Length Frequency ◽  
Lake Ecosystems ◽  
Exploitation Rate ◽  
Length Frequency Data

The Malayan leaf fish or locally named as kepor (Pristolepis grooti) is one of important biotic components in Ranau Lake ecosystems. This study aimed to estimate population dynamic and exploitation rate of kepor in Ranau Lake, South Sumatera. The population parameters are estimated based on length frequency data which were collected in March to October 2013. Growth parameters and fishing mortality rates were calculated using FiSAT software package. The results showed that kepor’s growth was negative allometric, which tended to gain length faster than weight. Kepor population was dominated (42%) by individual length of 10.0 to 11.0 cm. Predicted length infinity (L) was 17.28 cm with high value of growth rates (K) of 1.4 year-1. The natural mortality rate (M) is 2.57 year-1, the fishing mortality rate (F) is 5.36 year-1 and total mortality rate (Z) is 7.93 year-1. The exploitation rate of Malayan leaf fish in Ranau Lake (E = 0.68 year-1) has passed the optimum score.  

Integrating catch-at-age and multiyear tagging data: a combined Brownie and Petersen estimation approach in a fishery context

2006 ◽  
Vol 63 (3) ◽  
pp. 534-548 ◽  
Author(s):  
Tom Polacheck ◽  
J Paige Eveson ◽  
Geoff M Laslett ◽  
Kenneth H Pollock ◽  
William S Hearn
Keyword(s):  
Mortality Rate ◽  
Population Size ◽  
Stock Assessment ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Catch Data ◽  
Coefficients Of Variation ◽  
Southern Bluefin Tuna ◽  
Catch Rates ◽  
Comprehensive Framework

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.

scholarly journals DINAMIKA POPULASI IKAN GABUS (Channa striata) DI RAWA DANAU PANGGANG, KALIMANTAN SELATAN

2018 ◽  
Vol 14 (1) ◽  
pp. 16
Author(s):  
Dini Sofarini ◽  
Mohammad Mahmudi ◽  
Asus Maizar S. Hertika ◽  
Endang Yuli Herawati
Keyword(s):  
Growth Rate ◽  
Mortality Rate ◽  
Population Dynamic ◽  
Growth Pattern ◽  
Total Mortality ◽  
Natural Mortality ◽  
Von Bertalanffy ◽  
Fishery Resource ◽  
Exploitation Rate ◽  
Channa Striata

The province of South Kalimantan has the largest peat swamp that is named Danau Panggang Swamp with an area of 5,390.7 Ha. This swamp has ecological, economic and potential functions of a large fishery resource. The purposes of this study are to evaluate the exploitation rate of Snake Head Fish (Channa striata) in Danau Panggang Swamp, by population dynamic analysis using FISAT program of Von Bertalanffy method.  The results showed that the growth pattern of Snake Head Fish (Channa striata) has the tendency to grow negative allometric with 63.4 cm of long infifer (L¥), growth rate (k) 0.15 per year, theoretical age at the time of the fish is equal to 0 (t0) is -1.48257 years. While the natural mortality rate (M) was 0.43, the mortality rate due to catch (F) of 0.69/year and the total mortality rate  (Z) of 1.12/year, and the rate of exploitation value E = 0.62.  These results indicated that the exploitation rate of Head Snake Fish (Channa striata) in Danau Panggang swamp has a tendency to overfishing.

scholarly journals Analisis dinamika populasi ikan selar kuning (Selaroides leptolepis) dalam upaya pengelolaan sumberdaya ikan pelagis kecil di perairan Bintan, Provinsi Kepulauan Riau

DEPIK ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 428-434
Author(s):  
Septiyawati Septiyawati ◽  
Muhammad Fauzi ◽  
Deni Efizon
Keyword(s):  
Mortality Rate ◽  
Total Mortality ◽  
Natural Mortality ◽  
Salted Fish ◽  
Fisheries Resources ◽  
Exploitation Rate ◽  
Raw Fish ◽  
Pelagic Fisheries

This raw fish is used as fisheries products such as salted fish, grilled fish, fishmeal and surimi. This study aims to analyze mortality and recruitment of yellowstipe scad (Selaroides leptolepis) and the information about management of small pelagic fisheries resources in Bintan Waters. This research was carried out in February-June 2019 at the Barek Motor Fish Landing Area (TPI) with fishing areas in Bintan waters. The number of fish studied was 2.550 with a length of 102-215 mm and a weight of 15-102 gr. The highest recruitment peak occurred in Mei of 18.11% and June of 19.48%. The highest and lowest condition factors are 0.83 and 1.09. The total mortality rate (Z) of yellow strait fish is 4.61 per year with a natural mortality rate (M) of 1.66 per year and the capture mortality rate of 2.95 per year so that the exploitation rate is 0.63. The death of yellowstipe scade in the Bintan Sea most of the caused by fishing activities (F) of 2.95 per year.Keywords:Yellowstipe scad Bintan WatersRecrutmentCondition factorsMortalityABSTRAKIkan selar kuning merupakan salah satu jenis ikan ekonomis penting. Ikan ini banyak dimanfaatkan sebagai bahan baku produk olahan perikanan seperti ikan asin, ikan bakar, pindang, tepung ikan dan surimi. Penelitian ini bertujuan untuk menganalisis, mortalitas dan rekrutmen ikan selar kuning (Selaroides leptolepis) dan informasi tentang pengelolaan sumberdaya ikan pelagis kecil di Perairan Bintan. Penelitian ini telah dilaksanakan bulan Februari-Juni 2019 di Tempat Pendaratan Ikan (TPI) Barek Motor dengan wilayah penangkapan di perairan Bintan. Jumlah ikan yang diteliti 2.550 ekor dengan panjang 102-215 mm dan berat 15-102 gr. Puncak rekrutmen tertinggi terjadi bulan Mei sebesar 18,11% dan Juni sebesar 19,48%,. Nilai tertinggi dan terendah faktor kondisi yaitu 0,82 dan 1,09. Laju mortalitas total (Z) ikan selar kuning 4,61 per tahun dengan laju mortalitas alami (M) 1,66 per tahun dan laju mortalitas penangkapan 2,95 per tahun sehingga diperoleh laju eksploitasi 0,63. Kematian ikan selar kuning di laut Bintan sebagian besar diakibatkan oleh aktivitas penangkapan (F) sebesar 2,95 per tahun.Kata kunci:Ikan selar kuning Perairan Bintan Rekrutmen Faktor kondisi Mortalitas

scholarly journals Mortality of the population of the Komi Region at the end of the – XIX beginning of the XX century: age composition

2021 ◽  
Vol 1 ◽  
pp. 11-14
Author(s):  
D.V. Vishnyakova ◽  
Keyword(s):  
Mortality Rate ◽  
Age Groups ◽  
Mortality Rates ◽  
Age Composition ◽  
Younger Age ◽  
Significant Concentration

The article describes some mortality rates of the population of the Komi Region in the late XIX-early XX century. The age composition of the deceased is revealed, with a distribution by gender. During the studied time, mortality was characterized by a significant concentration in younger age groups. The mortality rate of children under the age of five years averaged 55–70 % of the total number of deaths in the region.

scholarly journals Growth, maturation, and longevity of maturation cohorts of Norwegian spring-spawning herring

2004 ◽  
Vol 61 (2) ◽  
pp. 165-175 ◽  
Author(s):  
Raymond J.H. Beverton ◽  
Arvid Hylen ◽  
Ole-Johan Østvedt ◽  
John Alvsvaag ◽  
Terence C. Iles
Keyword(s):  
Mortality Rate ◽  
Small Proportion ◽  
Stock Assessment ◽  
Adult Life ◽  
Total Mortality ◽  
Mortality Rates ◽  
Natural Mortality ◽  
Marine Research ◽  
First Time ◽  
Age At Maturation

Abstract In 1907, the Bergen Institute of Marine Research started regular sampling of scales and lengths from landings of mature Norwegian spring-spawning herring. The actual age of each fish when caught was recorded, and from the early 1920s also the age at which it spawned for the first time. The present analyses concern biological samples secured during the fishing seasons 1940–1964. Herring in this stock do not all reach maturity at the same age. A small proportion of any one year class matures at 3 years. The majority matures from the age of 4–7 years, and a small proportion of some year classes at 8 and even 9 years of age. Subsequent age composition and growth of each maturation cohort were followed throughout mature life after spawning for the first time. The maximum age was found to increase with age at maturation, rising to an asymptote of about 22 years. The von Bertalanffy parameter L∞ shows an increasing trend with age at maturation, while K decreases. There is no strict length threshold at maturation and the curve joining the length at which each maturation cohort reaches maturity is less steep than the growth curve itself over the range of maturation ages. The data suggest that fish in this stock spawn, on average, eight times during a period of their life history in which the mortality rate is independent of age. After these eight spawnings, at an age referred to in this paper as the hinge age, the mortality rate increases sharply. Thus, the adult life is divided into two phases, called here pre-senescent and senescent. The total mortality rates in the pre-senescent phase are relatively stable for all maturation cohorts 3–9, but there is some evidence of a trend towards higher mortality rates during the senescent phase for the youngest maturing fish. This trend is caused mainly by a reduced natural mortality in the fish that mature when older. These findings have interesting demographic implications. Additional mortality due to fishing will change the relative contribution of young and old maturation cohorts in the senescent phase, thus making it appear that natural mortality is dependent on the intensity of fishing. Consequently, for stock assessment, analysis on a cohort basis seems advisable.

Determination of Natural and Fishing Mortalities of Cod and Haddock from Analysis of Tag Records off Western Nova Scotia

1958 ◽  
Vol 15 (6) ◽  
pp. 1371-1381 ◽  
Author(s):  
J. E. Paloheimo
Keyword(s):  
Nova Scotia ◽  
Mortality Rate ◽  
Total Mortality ◽  
Marine Species ◽  
First Year ◽  
Natural Mortality ◽  
Independent Estimate

With marine species the population of tagged fish is unlikely to be a closed one, and previously described methods of determining natural and fishing mortalities are then hardly applicable. It is shown that when no data on effort or catch, related to tag returns, are available, a relationship between fishing and natural mortalities can be calculated, subject to some restrictive assumptions. An independent estimate of total mortality is then necessary to arrive at values of natural and fishing mortality.The method is applied to taggings of cod and haddock off Nova Scotia (McCracken, 1956). For cod the calculations show wide variations in effort. We obtain a rather low value of the natural mortality in the first year of recoveries. In subsequent years the numbers of returns are so low that heavy losses of tags are suspected. For haddock the calculations show that the effort may be constant and that already developed methods (Leslie and Davies, Ketchen, DeLury, Beverton and Holt) may be applied. Results leave several alternative explanations possible, giving a range from 0 to.36 for the instantaneous natural mortality rate, depending on the unknown initial loss of tags.

Yield-per-recruit and egg-per-recruit analyses of the Omani abalone, Haliotis mariae

1995 ◽  
Vol 46 (3) ◽  
pp. 663 ◽  
Author(s):  
SA Shepherd ◽  
JL Baker ◽  
DW Johnson
Keyword(s):  
Mortality Rate ◽  
Sexual Maturity ◽  
Egg Production ◽  
Arabian Sea ◽  
Total Mortality ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Northern Arabian Sea ◽  
Size At Sexual Maturity ◽  
Yield Per Recruit

The fecundity, size at sexual maturity, sex ratios and total mortality of Haliotis mariae on the Dhofar coast of the northern Arabian Sea were measured. These data, and estimates of the growth rate, were used for yield-per-recruit and egg-per-recruit analyses. Maximum yields occur at 3+ to 4+ years of age, depending on the natural mortality rate chosen. At the present age at first capture egg production levels are 2-29% of the unfished stock, depending on estimates of the fishing mortality rate and the natural mortality rate, and are considered to be far too low to maintain recruitment. At 40% egg production, of the maximum possible the age at first capture is 4 to 4.5 years, i.e. 105-115 mm shell length, depending on site.

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