Management of evolving fish stocks

1998 ◽  
Vol 55 (8) ◽  
pp. 1971-1982 ◽  
Author(s):  
Mikko Heino
Keyword(s):  
Maximum Sustainable Yield ◽  
Evolutionary Change ◽  
Fish Stock ◽  
Sustainable Yield ◽  
Harvest Rate ◽  
Fish Stocks ◽  
Population Dynamics Model ◽  
Before And After ◽  
Age Structured ◽  
Delayed Maturation

Mortality caused by harvesting can select for life history changes in the harvested stock. Should this possibility be taken into account in the management of renewable resources? I compare the performance of different harvest strategies when evolutionary change is accounted for with the help of an age-structured population dynamics model. Assuming that age of first reproduction is the only evolving trait, harvesting of only mature individuals selects for delayed maturation and results in increased sustainable yields. Unselective harvesting of both mature and immature fish selects for earlier maturation which causes the sustainable yield to decrease. Constant stock size and constant harvest rate strategies perform equally well in terms of maximum sustainable yield, both before and after evolutionary change. The maximum sustainable yield for fixed-quota strategies is lower. All those strategies have similar evolutionary consequences given a similar average harvest rate. Coevolutionary dynamics between fish stock and the stock manager indicate that the evolutionary benefits of selective harvesting are attainable without incurring yield losses in the near future.

scholarly journals KETIDAKSTABILAN BESARAN STOK IKAN DARI MODEL PRODUKSI SURPLUS

2017 ◽  
Vol 13 (1) ◽  
pp. 1
Author(s):  
Suherman Banon Atmaja
Keyword(s):  
Maximum Sustainable Yield ◽  
Pelagic Fish ◽  
Purse Seine ◽  
Fish Stock ◽  
Sustainable Yield ◽  
Fish Stocks ◽  
Resources Management ◽  
Surplus Production ◽  
Fisheries Resources ◽  
Purse Seine Fishery

Selama ini, kerangka pengelolaan sumber daya ikan berdasarkan pada titik acuan nilai potensi dan kriteria maksimum (maximum sustainable yield), mengabaikan laju pertumbuhan stok ikan dan tanpa memperhatikan dinamika perikanan yang terjadi. Dari kombinasi data yang tersedia diperoleh hasil besaran nilai stok ikan yang bersifat dinamis, akibat perubahan yang terjadi pada parameter–parameter model produksi surplus. Tingkat maximum sustainable yield menunjukkan CMSY darimetode Gompertz lebih tinggi dibandingkan dengan metode logistik, sebaliknya tingkat EMSY lebih rendah dibandingkan dengan metode logistik. Konsekuensi perbedaan tersebut menghasilkan tingkat BMSY dan tercapai puncak titik jenuh dari perikanan pukat cincin berbeda, untuk metode Gompertz (37% dari biomassa awal) terjadi pada kurun waktu tahun 1978 sampai dengan 1981, sedangkan untuk metode logistik (50% dari biomassa awal) terjadi pada kurun waktu tahun 1990 sampai dengan 1992. Kondisi trend biomassa menunjukkan penurunan biomassa berkisar 92 sampai dengan 96,5% dari biomassa awal untuk metode Gompertz, sedangkan untuk metode logistik berkisar 70 sampai dengan 93%. Tampak perkembangan perikanan pukat cincin catch effort mengikuti fungsi pertumbuhan logistik daripada fungsi pertumbuhan Gompertz. Bagaimanapun, penyusutan stok ikan pelagis didukung oleh trend hasil tangkapan yang menurun, sedangkan hari operasi cenderung meningkat. During the time, framework of fisheries resources management was based on reference point of potency value and criteria (maximum sustainable yield), while net growth of fish stock and fisheries dynamics have been ignored. From data combination available obtaining result of size of fish stocks was dynamic due to change of parameters of surplus production. The Level maximum sustainable yield showes that CMSY method of Gompertz was higher than logistics method, on the contrary EMSY compared to lower than logistics method. Consequently, these results were obtained the level of BMSY (biomass at level maximum sustainable yield) and the peaks of exploitation from purse seine fishery were also diffrent, for Gompertz method revealed that the level of BMSY (37% from initially biomass) occurred in the period of 1978 to 1981, while logistics method (50% from initially biomass) occurred in the period of 1990 to 1992. Trend biomass in state of decline reached 92 to 96,5% from intially biomass for Gompertz method, while for the method of logistics reached 70 to 93% from intially biomass. Seems that the development of purse seine fisheries (catch effort) followed function growth logistics rather than the function growth Gompertz. However, the decrease of fish stock pelagic supported by the catch of pelagic fish showed a declining trend, while fishing days have tend to increase.

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 Towards an integrated forecasting system for fisheries on habitat-bound stocks

Ocean Science ◽  
2013 ◽  
Vol 9 (2) ◽  
pp. 261-279 ◽  
Author(s):  
A. Christensen ◽  
M. Butenschön ◽  
Z. Gürkan ◽  
I. J. Allen
Keyword(s):  
Climatic Variability ◽  
Maximum Sustainable Yield ◽  
Ecosystem Dynamics ◽  
Fish Stock ◽  
Generic Model ◽  
Sustainable Yield ◽  
Model Framework ◽  
The North ◽  
Basin Scale ◽  
Forecasting System

Abstract. First results of a coupled modelling and forecasting system for fisheries on habitat-bound stocks are being presented. The system consists currently of three mathematically, fundamentally different model subsystems coupled offline: POLCOMS providing the physical environment implemented in the domain of the north-west European shelf, the SPAM model which describes sandeel stocks in the North Sea, and the third component, the SLAM model, which connects POLCOMS and SPAM by computing the physical–biological interaction. Our major experience by the coupling model subsystems is that well-defined and generic model interfaces are very important for a successful and extendable coupled model framework. The integrated approach, simulating ecosystem dynamics from physics to fish, allows for analysis of the pathways in the ecosystem to investigate the propagation of changes in the ocean climate and to quantify the impacts on the higher trophic level, in this case the sandeel population, demonstrated here on the basis of hindcast data. The coupled forecasting system is tested for some typical scientific questions appearing in spatial fish stock management and marine spatial planning, including determination of local and basin-scale maximum sustainable yield, stock connectivity and source/sink structure. Our presented simulations indicate that sandeel stocks are currently exploited close to the maximum sustainable yield, even though periodic overfishing seems to have occurred, but large uncertainty is associated with determining stock maximum sustainable yield due to stock inherent dynamics and climatic variability. Our statistical ensemble simulations indicates that the predictive horizon set by climate interannual variability is 2–6 yr, after which only an asymptotic probability distribution of stock properties, like biomass, are predictable.

scholarly journals Comment on “Impacts of historical warming on marine fisheries production”

Science ◽  
2019 ◽  
Vol 365 (6454) ◽  
pp. eaax5721 ◽  
Author(s):  
Cody Szuwalski
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Maximum Sustainable Yield ◽  
Structured Data ◽  
Sea Surface ◽  
Sustainable Yield ◽  
Surplus Production ◽  
Production Models ◽  
Fitting Production ◽  
Age Structured

Free et al. (Reports, 1 March 2019, p. 979) linked sea surface temperature (SST) to surplus production and estimated a 4% decline in maximum sustainable yield (MSY) since 1930. Changes in MSY are expected when fitting production models to age-structured data, so attributing observed changes to SST is problematic. Analyses of recruitment (a metric of productivity in the same database) showed increases in global productivity.

Age-structured bioeconomic model for strategic interaction: an application to pomfret stock in the Arabian/Persian Gulf

2020 ◽  
Vol 77 (5) ◽  
pp. 1787-1795 ◽  
Author(s):  
A Ben-Hasan ◽  
C Walters ◽  
V Christensen ◽  
G Munro ◽  
U R Sumaila ◽  
...  
Keyword(s):  
Persian Gulf ◽  
Strategic Interaction ◽  
Maximum Sustainable Yield ◽  
Fish Stock ◽  
Bioeconomic Model ◽  
Fishing Activity ◽  
Commercial Fish ◽  
Trade Offs ◽  
Age Structured ◽  
Silver Pomfret

Abstract When fish stocks migrate across multiple exclusive economic zones (EEZs), they compel managers to examine management at both national and international levels. A strategic interaction emerges when the fishing activity of one country impacts fishing opportunities available for other countries sharing the stock. Left unaddressed, strategic interaction could lead to overexploitation and suboptimal payoffs. Here, we develop and apply a bioeconomic model to address the competitive fishing for silver pomfret in the Arabian/Persian Gulf—a highly commercial fish stock shared between Kuwait and Iran—and evaluate biological–economic trade-offs under competition, cooperation, and country-independent management using maximum sustainable yield (MSY) and fishing mortality that maintain MSY (Fmsy) policies. When cooperation involves an equal share of the overall Fmsy or a share based on the proportion of the stock available in each EEZ, countries are expected to cooperate given the substantially higher catch, biomass, and relative profits compared to other management regimes. However, other than these two arrangements, countries would favour different regimes. Besides providing policy insights to improve the perilous status of silver pomfret, our approach could be useful in exploring alternative fishing arrangements to sustainably harvest a transboundary fish stock while maximizing average yields.

Optimal F0.1 Criteria and Their Relationship to Maximum Sustainable Yield

1987 ◽  
Vol 44 (S2) ◽  
pp. s339-s348 ◽  
Author(s):  
R. B. Deriso
Keyword(s):  
Quantitative Relationship ◽  
Maximum Sustainable Yield ◽  
Sustainable Yield ◽  
Fish Stocks ◽  
Pacific Halibut ◽  
Western Lake ◽  
Gadus Macrocephalus ◽  
Hippoglossus Stenolepis ◽  
Stock Recruitment ◽  
Yield Per Recruit

There is a unique size of entry into the fishable population that maximizes yield per recruit when an F0.1 fishing criterion is applied to the simple theory of fishing developed by Beverton and Holt in 1957. I define such a pair of parameters (size of entry, F0.1 value) to be the optimal F0.1 criteria and show that they are characterized by the single quantity M/K. A quantitative relationship is established between maximum sustainable yield and the optimal F0.1 criteria for a model population where recruitment is governed by a Ricker stock–recruitment function. This new theory is applied to three fish stocks: Pacific halibut (Hippoglossus stenolepis), western Lake Erie walleye (Stizostedion vitreum vitreum), and Bering Sea Pacific cod (Gadus macrocephalus).

Experimental Harvest Policies for a Mixed-Stock Fishery: Fraser River Sockeye Salmon, Oncorhynchus nerka

1990 ◽  
Vol 47 (1) ◽  
pp. 145-155 ◽  
Author(s):  
Jeremy S. Collie ◽  
Randall M. Peterman ◽  
Carl J. Walters
Keyword(s):  
Regression Model ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Maximum Sustainable Yield ◽  
Sustainable Yield ◽  
Fraser River ◽  
Harvest Rate ◽  
Ricker Model ◽  
Exploitation Rate ◽  
Mixed Stock

We investigated harvest strategies aimed at rebuilding the less abundant stocks of Fraser River sockeye salmon, Oncorhynchus nerka. Monte Carlo simulations were run to estimate catch under four different harvest policy designs and three alternative parameterizations of the Ricker model. A pooled regression model was fit to 34 yr of spawner–recruit data from the 10 major stocks of Fraser sockeye. Compared with estimating separate parameters for each stock, the pooled regression model resulted in a more precise estimate of the Ricker a parameter (productivity at low stock sizes). Exploitation rate for maximum sustainable yield depends only on the a parameter and is thus well defined by the pooled regression even though the corresponding optimal escapement levels remain uncertain. A reduction in harvest rates to 70% from the current average 80% increased the simulated 40-yr catch by 31%. More extreme harvest-rate reductions, involving 50% exploitation rates on some stocks for four generations, allowed faster rebuilding and further increases in catch. Extreme harvest-rate reductions were necessary to obtain a 0.5 or greater probability of correctly detecting increased escapements, should the less-abundant runs increase as expected.

scholarly journals POTENTIAL PRODUCTION OF DEMERSAL FISH STOCK IN THE MALACCA STRAIT OF INDONESIA

2015 ◽  
Vol 21 (1) ◽  
pp. 45 ◽  
Author(s):  
Purwanto Purwanto
Keyword(s):  
Demersal Fish ◽  
Fishing Effort ◽  
Maximum Sustainable Yield ◽  
Fish Stock ◽  
Sustainable Yield ◽  
Optimum Level ◽  
Fish Production ◽  
Potential Production ◽  
Malacca Strait

Malacca Strait is one of the main fishing areas for demersal fishery in Indonesia. To support the management of that fishery, an assessment of the demersal fish stock was conducted. This study estimated that the maximum sustainable yield and the optimal catch per unit effortof demersal fishery in the Malacca Strait were about 106.8 thousand tons/year and 28.5 tons per unit of Danish seine, respectively, resulting from the operation of 3,752 Danish seines. Unfortunately, fishing effort was higher than its optimum level and the fish stock was over-exploited since 2003. To recover the demersal fish stock to its optimum level and to ensure the optimal fish production from demersal fishery in the Malacca Strait, it was necessary to reduce fishing effort at about 67% from its level in 2011.

Sign in / Sign up

Export Citation Format

Share Document