Relationship of Fishing Mortality to Natural Mortality at the Level of Maximum Sustainable Yield Under the Logistic Stock Production Model

1974 ◽  
Vol 31 (9) ◽  
pp. 1539-1542 ◽  
Author(s):  
Robert C. Francis
Keyword(s):  
Mortality Rate ◽  
Maximum Sustainable Yield ◽  
Production Model ◽  
Sustainable Yield ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Practical Utility ◽  
Relationship Of

The often-used approximation that, for a stock of fish under exploitation, the instantaneous fishing mortality rate equals the instantaneous natural mortality rate at the point of the maximum sustainable yield is examined with respect to its mathematical roots and practical utility. Examples from two diverse fisheries are utilized.

Relationship of Fishing Mortality to Natural Mortality and Growth at the Level of Maximum Sustainable Yield

1982 ◽  
Vol 39 (7) ◽  
pp. 1054-1058 ◽  
Author(s):  
R. B. Deriso
Keyword(s):  
Logistic Model ◽  
Mortality Rates ◽  
Maximum Sustainable Yield ◽  
Sustainable Yield ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Difference Model ◽  
Relationship Of ◽  
Yield Per Recruit ◽  
Delay Difference

Fishing mortality constraints are derived for fishes harvested at the maximum sustainable yield (MSY) determined by a delay-difference population model. Those constraints depend upon rates of natural mortality and growth as well as a simple constraint placed on abundance of the exploited population. The results are generalized for a wider class of population models where it is shown that MSY fishing mortality is constrained often to be less than the fishing mortality which maximizes yield per recruit. Fishing mortality rates are lower in the delay difference model in comparison to MSY fishing rates in the logistic model, when a quadratic spawner–recruit curve is applied.Key words: delay-difference model, logistic model, fishing mortality, maximum sustainable yield, yield per recruit

scholarly journals Can stock–recruitment points determine which spawning potential ratio is the best proxy for maximum sustainable yield reference points?

2013 ◽  
Vol 70 (6) ◽  
pp. 1075-1080 ◽  
Author(s):  
Christopher M. Legault ◽  
Elizabeth N. Brooks
Keyword(s):  
Life History ◽  
Mortality Rate ◽  
Maximum Sustainable Yield ◽  
Reference Points ◽  
Sustainable Yield ◽  
Marine Science ◽  
Fishing Mortality ◽  
Scatter Plots ◽  
Stock Recruitment ◽  
Spawning Potential Ratio

Abstract Legault, C. M., and Brooks, E. N. 2013. Can stock–recruitment points determine which spawning potential ratio is the best proxy for maximum sustainable yield reference points? – ICES Journal of Marine Science, 70: 1075–1080. The approach of examining scatter plots of stock–recruitment (S–R) estimates to determine appropriate spawning potential ratio (SPR)-based proxies for FMSY was investigated through simulation. As originally proposed, the approach assumed that points above a replacement line indicate year classes that produced a surplus of spawners, while points below that line failed to achieve replacement. In practice, this has been implemented by determining Fmed, the fishing mortality rate that produces a replacement line with 50% of the points above and 50% below the line. A new variation on this approach suggests FMSY proxies can be determined by examining the distribution of S–R points that are above or below replacement lines associated with specific SPRs. Through both analytical calculations and stochastic results, we demonstrate that this approach is fundamentally flawed and that in some cases the inference is diametrically opposed to the method's intended purpose. We reject this approach as a tool for determining FMSY proxies. We recommend that the current proxy of F40% be maintained as appropriate for a typical groundfish life history.

Production, Mortality, And Sustainable Yield Of Northwest Atlantic Harp Seals (Pagophilus groenlandicus)

1978 ◽  
Vol 35 (9) ◽  
pp. 1249-1261 ◽  
Author(s):  
G. H. Winters
Keyword(s):  
Population Size ◽  
Total Population ◽  
Historical Data ◽  
Maximum Sustainable Yield ◽  
Sustainable Yield ◽  
Natural Mortality ◽  
Northwest Atlantic ◽  
The Past ◽  
Relative Contribution ◽  
Pagophilus Groenlandicus

From recent and historical data the natural mortality rate of adult harp seals (Pagophilus groenlandicus) is estimated to be 0.10 which is within the range of previous estimates (0.08–0.11). New estimates of bedlamer and 0-group natural mortality rates were not significantly different from those of adult seals. Pup production estimates from survival indices agreed well with those from sequential population analyses and indicated a decline from about 350 000 animals in the early 1950s to about 310 000 animals in the early 1970s. Over the same period the 1+ population size declined from 2.5 to 1.1 million animals but has been increasing at the rate of 3%/yr since the introduction of quotas in 1972. The relative contribution of the "Front" production to total ("Front" plus Gulf) production during the past decade has fluctuated from 49 to 87%, the average of 64% being very similar to the 61% obtained previously. These fluctuations suggest some interchange between "Front" and Gulf adults and it is concluded that homing in the breeding areas is a facultative rather than obligatory aspect of seal behavior. Thus the heavier exploitation of the "Front" production is probably sufficiently diffused into the total population to avoid serious effects on "Front" production. The maximum sustainable yield of Northwest Atlantic seals harvested according to recent patterns is estimated to be 290 000 animals (80% pups) from a 1+ population size of 1.8 million animals producing 460 000 pups annually. The sustainable yield at present levels of pup production (335 000 animals) is calculated to be 220 000 animals which is substantially above the present TAC of 180 000 animals and coincides with present harvesting strategies designed to enable the seal hunt to increase slowly towards the MSY level. Key words: mortality, production, sustainable yield, population dynamics, marine mammal

Movement, Growth and natural mortality rate of the Red Spot King Prawn, Penaeus longistylus Kubo, from the Great Barrier Reef Lagoon

1990 ◽  
Vol 41 (3) ◽  
pp. 399 ◽  
Author(s):  
MCL Dredge
Keyword(s):  
Growth Rate ◽  
Mortality Rate ◽  
Great Barrier Reef ◽  
Annual Variation ◽  
Growth Parameters ◽  
Natural Mortality ◽  
Barrier Reef ◽  
Fishing Mortality ◽  
Nursery Areas ◽  
Reef Lagoon

Movement, growth and natural mortality rate of the red spot king prawn, Penaeus longistylus, occurring in waters of the Great Barrier Reef off Townsville, Queensland, were investigated in a series of tagging experiments. Adult P. longistylus did not migrate after leaving nursery areas. Their growth rate was slower than that of the conspecific species P. plebejus, and significant inter-annual variation in growth parameters was observed. The natural mortality rate, assessed by sequential tagging experiments that eliminated the possibility of confounding with the rate of fishing mortality, was estimated to be 0.072 (week-1).

Influence of errors in natural mortality estimates in cohort analysis

1997 ◽  
Vol 54 (7) ◽  
pp. 1608-1612 ◽  
Author(s):  
G Mertz ◽  
R A Myers
Keyword(s):  
Mortality Rate ◽  
Similar Pattern ◽  
Cohort Analysis ◽  
Transient Behavior ◽  
Natural Mortality ◽  
Exact Formulation ◽  
Fishing Mortality ◽  
Bias Factor ◽  
Special Case ◽  
Mortality Estimates

The accuracy of the estimation of cohort strength from catch data may be greatly degraded if a poor estimate of the natural mortality rate is entered into the calculation. A straightforward, exact formulation for the error in cohort reconstruction due to a misspecified natural mortality rate is presented. The special case of constant fishing mortality is particularly transparent, allowing the error to be segmented into easily interpreted terms. A change in the fishing mortality may result in a distinct hump in the transient behavior of the bias factor, rather than a simple monotonic adjustment. This implies a similar pattern in estimated cohort strength.

Spatial variation in fishing intensity and its effect on yield

2008 ◽  
Vol 65 (4) ◽  
pp. 588-599 ◽  
Author(s):  
Stephen Ralston ◽  
Michael R O’Farrell
Keyword(s):  
Spatial Variation ◽  
Local Density ◽  
Life Stage ◽  
Maximum Sustainable Yield ◽  
Recruitment Rate ◽  
Sustainable Yield ◽  
Fishing Mortality ◽  
Density Dependent ◽  
Age Structured ◽  
Effect On Yield

Fishing mortality is rarely, if ever, evenly distributed over space, yet this is a common assumption of many fisheries models. To evaluate the effect of spatial heterogeneity in fishing mortality on yield, we constructed age-structured models that allowed for differing levels of fishing in three regions within the boundaries of a stock and explored alternative assumptions about the life stage in which density-dependent compensation operates. If the fishing mortality rate (F) is not excessive (i.e., F ≤ FMSY defined for the spatially homogeneous case; MSY, maximum sustainable yield), simulations demonstrated that minor to moderate spatial variation in fishing intensity does not impact sustainable yield. However, if fishing mortality is excessive (F > FMSY), spatial variation in fishing intensity often improves yield and can actually produce yields in excess of MSY when compensation occurs after dispersal, and the density-dependent recruitment rate is a function of the local density of adults. The yield premium generated in these simulations by postdispersal density dependence is due to a low level of compensatory mortality in heavily fished areas coupled with dispersal of propagules into these areas from lightly fished adjacent regions.

scholarly journals INTER-SPECIFIC COMPETITION AND FISHING EFFECT TO POPULATION DYNAMIC OF BALI SARDINE (SARDINELLA LEMURU)

2017 ◽  
Vol 22 (2) ◽  
pp. 85
Author(s):  
Andhika Prima Prasetyo ◽  
Rudy Masuswo Purwoko
Keyword(s):  
Mortality Rate ◽  
Population Dynamic ◽  
Positive Response ◽  
Fishing Pressure ◽  
Fishing Mortality ◽  
Precautionary Approach ◽  
Dramatic Decline ◽  
Stock Recruitment ◽  
Juvenile Population ◽  
Relationship Of

Stock-recruitment relationship of Bali sardine was investigated based on Beverton-Holt model by assuming inter-specific competition. Model is modified to incorporate the effect of fishing pressure that is density-independent to population dynamic by developing scenario fishing on adult and/or juvenile population. The results show that harvested adult the dramatic decline of recruitment supply. However, harvested juvenile is led to the positive response to population size, as an increase in fishing mortality rate will reduce competition mortality rate. Precautionary approach required by considering bipartite life cycle. 

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.  

scholarly journals Sustainable Potential of Tuna Fishery Around the Waters of North Sulawesi Province Based on Data from the Bitung Ocean Fisheries Port (PPS)

2019 ◽  
Vol 10 (1) ◽  
pp. 18
Author(s):  
Donald H. Simanjuntak ◽  
Lawrence J. L. Lumingas ◽  
Joudy R. R. Sangari
Keyword(s):  
Secondary Data ◽  
Fishing Effort ◽  
Maximum Sustainable Yield ◽  
Production Model ◽  
Utilization Rate ◽  
Sustainable Yield ◽  
North Sulawesi ◽  
Surplus Production Model ◽  
Tuna Fishing ◽  
Tuna Fisheries

This research was conducted in the city of Bitung, North Sulawesi Province with activities centered on the Bitung Ocean Fisheries Port (PPS), which began from mid March to April 2019. The fishing activities studied are using the fishing areas around the waters of  North Sulawesi Province namely the Sulawesi Sea and The Maluku Sea which are included in WPP 715 and 716 based on tuna catch landed data on PPS Bitung. The purpose of this study was to analyze the value of sustainable potential by looking at the level of utilization and Maximum Sustainable Yield (MSY) of tuna in the waters around North Sulawesi Province based on a surplus production model approach (Schaefer Model). This research is expected to be used as a consideration in the management of tuna stocks around the waters of North Sulawesi Province, and can be used as a basis for further research. This study uses a secondary data collection method in the form of fishery statistics documents. The data used are data from tuna fishing and fishing (effort), from 2014 to 2018 (5 years). The results showed that the sustainable potential of tuna fisheries around the waters of North Sulawesi Province based on North Sulawesi PPS data indicated that, the sustainable potential value of tuna that could be caught was 14,173.51 tons / year which is counted as 80% of the value of tuna resources around the waters of North Sulawesi Province. PPS Bitung data which amounted to 17,716.15 tons / year for Hmsy, 1,200.15 trips / year for Emsy, with an average CPUE value of 2014-2018 of 19 tons / trip. The level of tuna utilization around the waters of North Sulawesi Province is based on data from PPS Bitung in 2014, 2017 and 2018 which indicate that there were indications of overfishing with the largest utilization rate in 2014 which reached a value of 155.09%.Keywords: tuna, Bitung, Bitung PPS, sustainable potential, MSY. ABSTRAKKegiatan penelitian ini berlangsung di Kota Bitung, Provinsi Sulawesi Utara dengan kegiatan berpusat di Pelabuhan Perikanan Samudera (PPS) Bitung, yang dimulai  dari pertengahan bulan Maret hingga bulan April 2019. Aktivitas perikanan tangkap yang ditelaah berlangsung di sekitar perairan Provinsi Sulawesi Utara yaitu Laut Sulawesi dan Laut Maluku yang masuk ke dalam WPP 715 dan 716 berdasarkan data tangkapan tuna yang didaratkan di PPS Bitung. Tujuan dari penelitian ini adalah untuk menganalisis nilai potensi lestari dengan melihat tingkat pemanfaatan dan maximum sustainable yield (MSY) ikan tuna di sekitar perairan Provinsi Sulawesi Utara berdasarkan pendekatan model produksi surplus (Model Schaefer). Penelitan ini diharapkan dapat digunakan sebagai bahan pertimbangan dalam pengelolaan stok ikan tuna di sekitar perairan Provinsi Sulawesi Utara, serta dapat digunakan sebagai dasar untuk penelitian selanjutnya.  Penelitian ini menggunakan metode pengumpulan data sekunder berbentuk dokumen. Data yang diambil adalah data tangkapan ikan tuna dan upaya penangkapan ikan atau effort (trip), dari tahun 2014 sampai dengan 2018 (5 Tahun). Hasil penelitian menunjukkan potensi lestari perikanan tuna di sekitar perairan Provinsi Sulawesi Utara berdasarkan data PPS Bitung Sulawesi Utara nilai potensi lestari tuna yang bisa ditangkap adalah 14.173,51 ton/tahun 80% dari nilai pemanfaatan sumber daya perikanan tangkap tuna di sekitar perairan Provinsi Sulawesi Utara berdasarkan data PPS Bitung yang sebesar 17.716,15 ton/tahun untuk Hmsy, 1.200,15 trip/tahun untuk Emsy, dengan nilai CPUE rata-rata tahun 2014-2018 sebesar 19 ton/trip. Tingkat pemanfaatan tuna di sekitar perairan Provinsi Sulawesi Utara berdasarkan data PPS Bitung Sulawesi Utara di tahun 2014,2017 dan 2018 sudah yang menandakan adanya indikasi overfishing dengan tingkat pemanfaatan terbesar di tahun 2014 yang mencapai nilai 155,09%.Kata Kunci: ikan tuna, Bitung, PPS Bitung, potensi lestari, MSY.

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.

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