Estimation of fishing and natural mortality from tagging studies on fisheries with two user groups

1998 ◽  
Vol 55 (9) ◽  
pp. 2001-2010 ◽  
Author(s):  
Elizabeth N Brooks ◽  
Kenneth H Pollock ◽  
John M Hoenig ◽  
William S Hearn
Keyword(s):  
Fishing Effort ◽  
Standard Errors ◽  
Natural Mortality ◽  
Good Precision ◽  
User Group ◽  
Fishing Mortality ◽  
Factors Affecting ◽  
Multiple User ◽  
Potential Gain ◽  
User Groups

We present generalizations of fishery models that allow for the separate estimation of fishing mortality when more than one user group is present (e.g., a commercial and a recreational fishery). This model also allows for the fisheries to be in operation for any length of time whereas previously fisheries were generally considered to be pulse or continuous. Three cases are considered: (i) fisheries operate consecutively, (ii) fisheries overlap for a part of their seasons, and (iii) fisheries are in operation for the whole year. The results of a simulation study are included, which provide estimates of fishing and natural mortality along with their proportional standard errors (CVs). All scenarios had good precision, with most CVs < 25% and usually very little difference between the three cases. Coefficients of interaction, the potential gain by one fishery if another is closed down, are also given along with a method for calculating them. Factors affecting these coefficients of interaction were the order in which fisheries operated, amount of overlap in fishing seasons, and intensity of fishing effort by each fishery. We believe that these models could provide useful information for the management of fisheries with multiple user groups where allocation conflicts may arise.

scholarly journals Estimating natural and fishing mortality and tag reporting rate of southern rock lobster (Jasus edwardsii) from a multiyear tagging model

2001 ◽  
Vol 58 (12) ◽  
pp. 2490-2501 ◽  
Author(s):  
S D Frusher ◽  
J M Hoenig
Keyword(s):  
Mortality Rates ◽  
Fishing Effort ◽  
Reporting Rate ◽  
Standard Errors ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Rock Lobster ◽  
Relative Standard ◽  
Jasus Edwardsii ◽  
Mortality Estimates

Fishing and natural mortality rates and tag reporting rate for rock lobsters (Jasus edwardsii) in northwest Tasmania, Australia, were estimated using multiyear tagging models. These estimates are necessary for assessment of the resource. Several models were examined that had either two or three tagging events each year, and either combined sexes or kept sexes separate. The model that best described the dynamics of the fishery utilized three tagging events within a year. The year was divided into discrete periods and, within each year, fishing effort and duration of period were used to apportion fishing and natural mortalities, respectively, to the periods. The separation of fishing mortalities by sex was not found to improve the models. Although high (1.0–1.2·year–1), the instantaneous fishing mortality estimates were comparable to estimates obtained from other methods and the relative standard errors were low. Reporting rate estimates were also precise and indicated a lack of participation by the fishing industry. Estimates of natural mortality were low (0.00–0.02·year–1) but imprecise.

The Effect of Reduction of Fishing Effort on Yield

1962 ◽  
Vol 19 (4) ◽  
pp. 521-529 ◽  
Author(s):  
Syoiti Tanaka
Keyword(s):  
Mortality Rate ◽  
Sudden Change ◽  
Japan Sea ◽  
Fish Population ◽  
Fishing Effort ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Yield Curves ◽  
Before And After ◽  
Steady Level

When a fish population has been depleted by heavy exploitation, with the yield from the population maintaining an unfavourable level, it is usual to expect that the situation will be improved by reduction of fishing effort. Following a sudden reduction of fishing mortality, p, from p1 to p2 at time τ = 0, the yield at once decreases and then increases gradually until it reaches another steady level higher than the former level.The present paper deals, using Baranov's model, with the transition stage of the population following a sudden change in p, as well as with the steady state before and after the change. Relations between equilibrium yield and fishing mortality rate (effort-yield curves) are calculated for various values of the parameters, λ0 (= l0/u, where l0 is the length of a recruit and u is the yearly increase in length), q (natural mortality rate), and b (remaining life span of a fish at the time of recruitment) (Fig. 2). It is noteworthy that for species that grow slowly after recruitment, i.e. when λ0 is large, reduction of fishing would have scarcely any effect on the yield (Fig. 4).Yield curves for the period of transition from the present to various lower levels of fishing are calculated for the case in which λ0 = 4, q = 0.15, b = 10 and p1 = 1.35. These represent parameters for the present state of the stock of sohachi flounders Cleisthenes herzensteini (Schmidt), in the southwestern area of the Japan Sea (Fig. 5).Possible density effects on growth rate and natural mortality rate, which are briefly discussed, appear to diminish considerably the effectiveness of any reduction in fishing effort (Fig. 6).

scholarly journals Multiyear tagging studies incorporating fishing effort data

1998 ◽  
Vol 55 (6) ◽  
pp. 1466-1476 ◽  
Author(s):  
John M Hoenig ◽  
Nicholas J Barrowman ◽  
William S Hearn ◽  
Kenneth H Pollock
Keyword(s):  
Mortality Rate ◽  
Additional Data ◽  
Survival Rates ◽  
Fishing Effort ◽  
Reporting Rate ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Recovery Rates ◽  
Sampling Survey ◽  
Tag Shedding

The Brownie models for multiyear tagging studies can be used to estimate age- and year-specific annual survival rates and tag recovery rates. The latter are composites of the exploitation rates and rates of tag reporting, tag shedding, and tag-induced mortality. It is possible to estimate the exploitation rates if the other components of the tag recovery rates can be quantified. Instantaneous rates of fishing and natural mortality can be estimated if information is available on the seasonal distribution of fishing effort. The estimated rates are only moderately dependent on the timing of the fishing; consequently, the relative effort data can be crude. Information on the timing of the catch over the course of the year can be used as a substitute for the effort data. Fishing mortality can also be assumed to be proportional to fishing effort over years; consequently, if fishing effort is known then the tag reporting rate, natural mortality rate, and a single catchability coefficient can be estimated (instead of natural mortality and a series of fishing mortalities). Although it is possible in theory to estimate both the tag reporting rate and the natural mortality rate with all of these models, in practice it appears necessary to obtain some additional data relating to tag reporting rate to obtain acceptable results. The additional data can come from a variable reward tagging study, a creel or port sampling survey, or from tagged animals that are secretly added to the fishers' catches.

scholarly journals BEBERAPA PARAMETER POPULASI UDANG PUTIH (Penaeus merguiensis de Mann) DI PERAIRAN TARAKAN, KALIMANTAN UTARA

2017 ◽  
Vol 9 (2) ◽  
pp. 85
Author(s):  
Umi Chodrijah ◽  
Ali Suman
Keyword(s):  
Mortality Rate ◽  
Total Mortality ◽  
Fishing Effort ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Population Parameters ◽  
Spawning Period ◽  
Exploitation Rate ◽  
First Maturity ◽  
Penaeus Merguiensis

Tingkat eksploitasi udang putih (Penaeus merguiensis) sangat intensif. Hal ini terindikasi dengan hasil tangkapan udang di WPP-NRI 716 selama 9 tahun terakhir meningkat. Tujuan penelitian ini untuk mengkaji beberapa parameter populasi dan aspek biologi udang putih di perairan Tarakan. Data panjang karapas dan tingkat kematangan gonad udang putih dikumpulkan dari tempat pendaratan udang di Selumit Pantai, Tarakan, Kalimantan Utara pada Januari sampai dengan November 2016. Pendugaan parameter populasi dengan aplikasi model analisis menggunakan program ELEFAN 1. Hasil penelitian menunjukkan rata-rata ukuran udang putih pertama kali tertangkap (Lc) pada panjang karapas 32,51 mm dan rata-rata ukuran pertama kali matang gonad 33,58 mm. Puncak musim pemijahan terjadi pada Maret dan Agustus. Laju pertumbuhan (K) sebesar 1,33 per tahun (betina) dan 1,55 per tahun (jantan). Laju kematian total (Z) sebesar 7,5 per tahun (betina) dan 8,85 per tahun (jantan), laju kematian alamiah (M) sebesar 1,82 per tahun (betina) dan 2,16 per tahun (jantan) serta laju kematian akibat penangkapan (F) sebesar 5,68 per tahun (betina) dan 6,69 per tahun (jantan). Laju pengusahaan (E) udang putih di perairan Tarakan adalah sebesar 0,76 per tahun. Hal ini menunjukkan tingkat pemanfaatan udang putih telah mengalami lebih tangkap (overfishing). Kondisi ini menggambarkan perlunya dilakukan pengurangan upaya sekitar 52 %.  The banana prawn (Penaeus merguiensis) have been exploited intensively. For instance, within nine years the number of shrimp production in FMA 716 increased dramatically. This research aims to identify the some population parameters of banana prawn in the Tarakan waters. This research was carried out from January to November 2016. Data were analyzed using the analytical model application with ELEFAN I. The result showed that the length at first capture (Lc) of banana prawn was 32,51 mmCL and the length at first maturity (Lm) was 33,58 mm CL. The peak season of spawning period was indicated on March and August. The growth rate (K) was 1,33 /year (female) and 1.55/year (male). Total mortality rate (Z) was 7.5/year (female) and 8,85/year (male), natural mortality rate (M) rate was 1.82/year (female) and 2.16/year (male) and fishing mortality rate ( F) were 5.68/ year (female) and 6.69/year (male). The exploitation rate (E) of banana prawn in the Tarakan waters was 0.76 per year. Therefore, level of existing fishing effort of the banana prawn should reduced about 52 % in the next year.

scholarly journals PARAMETER POPULASI IKAN KAKAP LAUT-DALAM (Etelis radiosus, Anderson 1981) DI PERAIRAN TELUK CENDERAWASIH, PAPUA

2017 ◽  
Vol 8 (2) ◽  
pp. 125
Author(s):  
Nurulludin Nurulludin ◽  
Suprapto Suprapto ◽  
Prihatiningsih Prihatiningsih
Keyword(s):  
Deep Sea ◽  
Scientific Information ◽  
Fork Length ◽  
Fishing Effort ◽  
Length Measurement ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Growth Coefficient ◽  
Exploitation Rate

Ikan kakap laut-dalam (Etelis radiosus) adalah salah satu sumberdaya demersal ekonomis penting di Indonesia. Informasi ilmiah tentang ikan kakap laut-dalam ini masih sangat jarang, terutama dari kawasan Teluk Cenderawasih bagian Utara Papua. Penelitian ini dilaksanakan bulan Februari – November 2013 di Teluk Cenderawasih. Aanalisis panjang cagak ikan terhadap 3.255 ekor menggunakan software FISAT II, diperoleh beberapa nilai parameter populasi sebagai berikut: laju pertumbuhan (K) sebesar 0,17 per tahun, panjang asimtotik (L ) 108,68 cm FL, laju kematian alami (M) 0,4 pertahun, dan laju kematian karena penangkapan (F) 0,17 per tahun. Estimasi tingkat ekploitasi (E) sebesar 0,30 memiliki pengertian bahwa tingkat pemanfaatan ikan kakap laut dalam masih di rendah dan dapat ditingkatkan. Deep-sea snapper (Etelis radiosus) is one of high economic valued of demersal resources in Indonesia. Scientific information on deep-sea snapper is limited, especially from the northern part of Cenderawasih Gulf, Papua. This paper aims to determine some parameters populations of deepsea snapper (Etelis radiosus) in the gulf of Cenderawasih, Papua. The research conducted in February - November 2013 in the Gulf of Cenderawasih. Deepsea snapper fork length measurement randomly taken from 3.255 fishes in Nabire. The result obtained that the growth coefficient (K), asymptotic length (Linf)), natural mortality (M), fishing mortality (F) and exploitation rate (E) were 0.17/ year, 108.68 cmFL, 0.4/year, 0.17/year and 0.30/year. That implied the deepsea snapper fishing exploitation is under exploitation and there possibility of precountionary increasing of fishing effort.

scholarly journals GROWTH AND EXPLOITATION STATUS (Channa striata Bloch, 1793) IN LUBUK LAMPAM FLOODPLAINS, SOUTH SUMATERA

2013 ◽  
Vol 19 (1) ◽  
pp. 1
Author(s):  
Zulkarnaen Fahmi ◽  
Syarifah Nurdawati ◽  
Freddy Supriyadi
Keyword(s):  
Relative Yield ◽  
Total Mortality ◽  
Fishing Effort ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Population Parameters ◽  
Future Plan ◽  
Channa Striata ◽  
Exploitation Status ◽  
Yield Per Recruit

Due to the economic importance of C. striata in Lubuk Lampam floodplains (Indonesia), this study is aimed to estimate the biological and population parameters required for proposing a future plan to sustain and manage this valuable fish resource. The growth, mortality and explotation ratio of <em>Channa striata</em> estimated by employing FiSATProgramme are reported. The parameters of Von Bertalanffy growth model of 1,529 sample fishes were estimated as K= 0.36/ year, L” = 72.98 cm and to = -0.52 year. The coefficients of total mortality (Z), natural mortality (M) and fishing mortality (F) were 1.72, 0.73 and 0.99 year-1 respectively. Relative yield per recruit analysis shows that the presentexploitation rate (E) was 0.58. Yield per recruit can be maximized at the exploitation ratio of 0.5 and Lc/Linf values of 0.3. The Yield per recruit and biomass per recruit models indicated that, the fisheries status of <em>C. striata</em> in Lubuk Lampam floodplains exceed the limit reference point (Fmax), thus stock of this species in Lubuk Lampam floodplains is indicated being driving down.Reduction in fishing effort and increase number of selective fishing gears are suggested to sustain the fishery of <em>Channa striata</em> in Lubuk Lampam floodplains.

scholarly journals Yield per recruit of the peacock bass Cichla monoculus (Spix and Agassiz, 1831) caught in Lago Grande at Manacapuru (Amazonas – Brazil)

2014 ◽  
Vol 74 (1) ◽  
pp. 226-230 ◽  
Author(s):  
CP Campos ◽  
CEC Freitas
Keyword(s):  
Growth Parameters ◽  
Fishing Effort ◽  
Maximum Sustainable Yield ◽  
Minimum Size ◽  
Small Scale ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Yield Per Recruit ◽  
Peacock Bass ◽  
Actual Size

We evaluated the stock of peacock bass Cichla monoculus caught by a small-scale fishing fleet in Lago Grande at Manacapuru. The database was constructed by monthly samplings of 200 fish between February 2007 and January 2008. We measured the total length (cm) and total weight (gr) of each fish. We employed previously estimated growth parameters to run a yield per recruit model and analyse scenarios changing the values of the age of the first catch (Tc), natural mortality (M), and fishing mortality (F). Our model indicated an occurrence of overfishing because the fishing effort applied to catch peacock in Lago Grande at Manacapuru is greater than that associated with the maximum sustainable yield. In addition, the actual size of the first catch is almost half of the estimated value. Although there are difficulties in enforcing a minimum size of the catch, our results show that an increase in the size of the first catch to at least 25 cm would be a good strategy for management of this fishery.

Managing Conflicting Water Resource Goals and Uncertainties in a Dam-Network by Exploring the Solution Space

2018 ◽  
Author(s):  
Lin Guo ◽  
Hamed Zamanisabzi ◽  
Thomas M. Neeson ◽  
Janet K. Allen ◽  
Farrokh Mistree
Keyword(s):  
Water Resource ◽  
Optimal Solution ◽  
Solution Space ◽  
User Group ◽  
Multiple User ◽  
Social Ecological ◽  
The Social ◽  
User Groups ◽  
Design Preferences ◽  
Conflicting Goals

In a multi-reservoir system, ensuring adequate water availability across reservoirs while managing conflicting goals under uncertainties are critical to making the social-ecological system sustainable. The priorities of multiple user-groups and availability of the water resource may vary with time, weather and other factors. Uncertainties such as variation in precipitation bring more complexity, which intensifies the discrepancies between water supply and water demand for each user-group. To reduce such discrepancies, we should satisfice conflicting goals, considering typical uncertainties. We observed that models are incomplete and inaccurate, which challenge the use of the single optimal solution to be robust to uncertainties. So, we explore satisficing solutions that are relatively insensitive to uncertainties, by incorporating different design preferences, identifying sensitive segments and improving the design accordingly. This work is an example of exploring the solution space to enhance sustainability in multidisciplinary systems, when goals conflict, preferences are evolving, and uncertainties add complexity.

scholarly journals Effects of spatial heterogeneity in growth and fishing effort on yield-per-recruit models: an application to the US Atlantic sea scallop fishery

2015 ◽  
Vol 73 (4) ◽  
pp. 1062-1073 ◽  
Author(s):  
Samuel B. Truesdell ◽  
Deborah R. Hart ◽  
Yong Chen
Keyword(s):  
Spatial Heterogeneity ◽  
Spatial Data ◽  
Egg Production ◽  
Fishing Effort ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Sea Scallop ◽  
The Us ◽  
The Impact ◽  
Yield Per Recruit

Abstract Conventional yield-per-recruit (Y/R) and spawning-stock biomass-per-recruit (SSB/R) models make no allowance for spatial heterogeneity in fishing mortality, natural mortality, or growth across the stock area, although variability in these processes can affect model results. For example, areas with higher growth and/or lower natural mortality rates should be fished at a lower rate to maximize Y/R; however, these areas may be especially attractive to fishers and are often fished harder. Here, Y/R and SSB/R models are developed that simultaneously account for spatial heterogeneity in growth and fishing effort. These models are applied to the US Atlantic sea scallop (Placopecten magellanicus) fishery. The spatial variability in growth uses depth-integrated models from the literature and variability in effort is based on, alternatively, uniform, observed, and relative-optimal spatial harvesting distributions. The observed effort patterns are derived from vessel monitoring system positions, and illustrate one application for these widely collected but underutilized spatial data. In this example, the distribution of observed fishing effort reduces Y/R compared with the relative-optimal, or the uniform effort distribution implicitly assumed by conventional Y/R analysis. SSB/R was in some cases considerably higher under the relative-optimal distribution of effort than when calculated using observed or uniform effort patterns. Such more realistic spatially integrated Y/R and SSB/R models can help to evaluate the impact of effort patterns on fishery yield and stock egg production. These models demonstrate that the spatial distribution of effort can be as important as the overall average fishing mortality when managing fisheries to optimize Y/R, SSB/R, and yield.

scholarly journals DINAMIKA POPULASI DAN TINGKAT PEMANFAATAN RAJUNGAN (Portunus pelagicus Linnaeus,1758) DI PERAIRAN TELUK JAKARTA

2018 ◽  
Vol 1 (1) ◽  
pp. 73
Author(s):  
Anthony Sisco Panggabean ◽  
Andina Ramadhani Putri Pane ◽  
Ap’idatul Hasanah
Keyword(s):  
Carapace Width ◽  
Fishing Effort ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Portunus Pelagicus ◽  
Relationship Analysis ◽  
Marine Crustaceans ◽  
Exploitation Rate ◽  
Main Target ◽  
First Maturity

Rajungan (Portunus pelagicus) merupakan salah satu jenis krustasea laut yang bernilai ekonomis penting yang menjadi target utama tangkapan di perairan Teluk Jakarta. Penelitian ini bertujuan untuk mengkaji dinamika populasi rajungan yang berguna sebagai dasar pengelolaannya. Penelitian dilakukan pada periode Januari sampai dengan November 2015. Hasil penelitian menunjukkan bahwa hubungan panjang berat rajungan bersifat allometrik positif dan rata-rata ukuran pertama kali matang gonad (Lm) sebesar 106,81 mm (lebar karapas), laju pertumbuhan (K) sebesar 1,0 per tahun dan lebar karapas infinitif (CW)  sebesar 157 mm. Laju kematian akibat penangkapan (F) sebesar 1,12 per tahun dan laju mortalitas alami (M) sebesar 1,14 per tahun. Laju eksploitasi (E) sudah berada pada tahapan penuh atau fully exploited, dengan demikian perlu adanya pengendalian upaya penangkapan.Blue swimming crabs (Portunus pelagicus) is one of the important marine crustaceans species forming the main target of fishing in the Jakarta Bay. This study aims to assess the population dynamics of crab for the basis e for their management. The study was conducted from January to November 2015. The result showed that carapace width and weigth relationship analysis was isometric and the estimated length at first maturity (Lm) was 106.81 mm (in carapace width), growth rate (K) was 1 mm per year, carapace width infinit (CW) was 157 mm, fishing mortality (F) was 1.12 per year and natural mortality rate (M) at about 1.14 per year. The exploitation rate (E) was predicted at fully exploited level, so that control of fishing effort are needed.

Sign in / Sign up

Export Citation Format

Share Document