Biomass Dynamics of Lake Superior Lake Herring (Coregonus artedii): Application of Schnute's Difference Model

1987 ◽  
Vol 44 (S2) ◽  
pp. s275-s288 ◽  
Author(s):  
Lawrence D. Jacobson ◽  
Wayne R. MacCallum ◽  
George R. Spangler
Keyword(s):  
General Trend ◽  
Lake Superior ◽  
Fishing Effort ◽  
Natural Mortality ◽  
Difference Model ◽  
Gill Nets ◽  
Thunder Bay ◽  
Biomass Dynamics ◽  
Coregonus Artedii ◽  
Lake Herring

Schnute's (1985. Can. J. Fish. Aquat. Sci. 42: 414–429) difference model was used to study the biomass dynamics of lake herring (Coregonus artedii) in Thunder Bay and Black Bay, Lake Superior, during 1948–79. Recruitment to both fisheries appeared to be independent of escapement during previous years. Abundance of lake herring in Black Bay varied without trend during the study period despite a strong peak in effective fishing effort during 1968–70 and a general trend of increasing effort throughout the study period. Abundance of Thunder Bay lake herring declined during 1948–50 and 1959–67 and increased when fishing effort declined. The estimated catchability coefficient for small-mesh gill nets (54–83 mm stretched measure) set in Black Bay for lake herring during November was 0.467/102 km net. The estimated catchability coefficient for small mesh gill nets set in Thunder Bay for lake herring during December was 0.132/102 km net. Estimates of natural mortality rates and recruitment levels for both fisheries were confounded and unreliable. This analysis demonstrates the utility of Schnute's model for management of Great Lakes herring stocks and some difficulties with its application.

Decline of Lake Herring (Coregonus artedii) In Lake Superior: An Analysis of the Wisconsin Herring Fishery, 1936–78

1982 ◽  
Vol 39 (4) ◽  
pp. 554-563 ◽  
Author(s):  
James H. Selgeby
Keyword(s):  
Lake Superior ◽  
Commercial Fishing ◽  
Productive Capacity ◽  
Spawning Areas ◽  
Spawning Stock ◽  
Coregonus Artedii ◽  
The 1960S ◽  
Lake Herring

Annual harvests of lake herring (Coregonus artedii) in American waters of Lake Superior declined from an average of 2 million kg in 1936–62 to less than 25 000 kg in 1978. Analysis of commercial fishing records revealed that the sequential overexploitation of discrete unit stocks caused the collapse of the herring population in Wisconsin waters. In each of six major spawning areas, catch exceeded the productive capacity of the stock and the stock failed. Because stocks in the six areas were exploited sequentially, mostly in groups of two or three simultaneously, the demise of the stocks was not readily apparent until the last two failed in the early 1960s. After the collapse of the last major spawning stock, the fishery dwindled but may have continued to overexploit the remaining small stocks. The residual populations were apparently able only to replace themselves. Some form of density-independent mortality was apparently operating to prevent their recovery during the 1960s and 1970s.Key words: lake herring, overfishing, Lake Superior

Predation by Rainbow Smelt (Osmerus mordax) on Lake Herring (Coregonus artedii) in Western Lake Superior

1978 ◽  
Vol 35 (11) ◽  
pp. 1457-1463 ◽  
Author(s):  
James H. Selgeby ◽  
Wayne R. MacCallum ◽  
Donald V. Swedberg
Keyword(s):  
Lake Superior ◽  
Commercial Production ◽  
Osmerus Mordax ◽  
Rainbow Smelt ◽  
Predator Prey ◽  
Western Lake ◽  
Large Numbers ◽  
Coregonus Artedii ◽  
Historical Levels ◽  
Lake Herring

The stock of lake herring (Coregonus artedii) in the Apostle Islands (Wisconsin) region of western Lake Superior has diminished severely during the past 30 yr, and predation by rainbow smelt (Osmerus mordax) on herring larvae has been considered a possible cause of this decline. In contrast, the herring stock in Black Bay, 160 km to the northeast, has remained nearly stable despite the presence of large numbers of smelt and high commercial production of herring. Predator–prey interactions were studied in both areas during 1974. Herring larvae and smelt were about 120 and 3 times as dense, respectively, in Black Bay as in the Apostle Islands region. Substantial predation by smelt on young herring was evident in Black Bay, where 17% of 1195 smelt stomachs examined contained herring larvae. From calculations of the relative densities of the two species, and of the daily ration of the predators, we estimated that smelt consumed 3.3–11% of the herring larvae. Nevertheless, the herring stocks have sustained average historical levels of commercial production. In contrast, no herring larvae were found in the stomachs of 1711 smelt collected in the Apostle Islands region. We conclude that predation by smelt on herring larvae is not the major factor controlling or suppressing herring stocks in either region. Key words: lake herring, rainbow smelt, predation, Lake Superior

Density-Dependent Maturation, Growth, and Female Dominance in Lake Superior Lake Herring (Coregonus artedii)

1991 ◽  
Vol 48 (4) ◽  
pp. 569-576 ◽  
Author(s):  
Stephen H. Bowen ◽  
Donna J. D'angelo ◽  
Stephen H. Arnold ◽  
Michael J. Keniry ◽  
Ronald J. Albrecht
Keyword(s):  
Sex Ratio ◽  
Egg Production ◽  
Lake Superior ◽  
Adult Mortality ◽  
Female Dominance ◽  
Low Density ◽  
Young Males ◽  
Recruitment Failure ◽  
Coregonus Artedii ◽  
Lake Herring

Density-related changes in age at maturation, sex ratio of recruits, growth, and fecundity at very low density result in spawning populations which comprise many older females and few young males and in which egg production per lake herring (Coregonus artedii) is increased by a factor of five. Age of maturation is delayed at low density for females, but not for males. Thus, males dominate the youngest age classes but females become increasingly more abundant from age 2 + through age 6 +. A model of lake herring population structure showed that although delayed maturation accounts for many characteristics of depressed populations, it does not explain overall population femaleness. The model was used to evaluate effects of differential adult mortality, recruitment failure, and changes in the sex ratio of recruits, and only the latter provided an adequate explanation for overall femaleness. Despite the apparently compensatory nature of these responses, the slow and unsteady recovery of depressed Lake Superior populations during the last two decades indicates that one or more additional factors play important roles in determination of year class strength.

Dynamics and Exploitation of Lake Whitefish in Southern Georgian Bay

1966 ◽  
Vol 23 (2) ◽  
pp. 221-274 ◽  
Author(s):  
Daniel Cucin ◽  
Henry A. Regier
Keyword(s):  
Mortality Rates ◽  
Exponential Model ◽  
Fishing Effort ◽  
Natural Mortality ◽  
Coregonus Clupeaformis ◽  
Commercial Catch ◽  
Georgian Bay ◽  
Gill Nets ◽  
Size At Age ◽  
Mean Risk

Instability of the population of Coregonus clupeaformis (Mitchill) in southern Georgian Bay from 1948 to 1964 was evidently partly due to intensive fishing.The population was discrete at least from 1956 to 1964 as determined by extensive tagging. From 1948 to 1964, estimated effective fishing effort varied 10-fold and annual yields almost 20-fold, with two cycles of abundance and scarcity. Strength of 1951–59 year-classes, defined as population size at age III, varied 40-fold. In spite of the marked instability, the population was in recent years more stable than any other whitefish population in Georgian Bay or Lake Huron.Almost all the commercial catch was made with gill nets of [Formula: see text] mesh. In 1957, fishing depended largely on age VII–IX fish; by 1964, on those of age V and VI. Apparent growth rate increased during this period: in 1957 age XII fish weighed 3.4 lb; in 1964 age VI weighed 3.7 lb. From 1959 to 1964, reproduction depended largely on males age IV+ and older and longer than 17 inches, and on females age V+ and older and longer than 18 inches.Natural mortality coefficients (exponential model) averaged 0.41 for fish of the 1948–58 year-classes beyond age III. Gillnetting was largely restricted to 2 months in late spring and two in fall. In each fishing season these gill nets took about 40% of the survivors of a year-class after it became fully vulnerable, at ages V, VI, and VII during the early 1960s.Combining growth and natural mortality rates in a biomass curve indicated that individual year-classes would provide highest yields when fished intensively at age IV, or slightly earlier than they were fished in the early 1960s. Yet the only hypothesis that might explain the continued existence of a fishable population was that relatively large parts of the habitat were either legally closed or unsuitable for fishing. Evidently the fishing was intense and increasing the effort would mean risk of a population collapse.

Fishery simulation model for sharks applied to the Gummy Shark, Mustelus antarcticus Gunther, from Southern Australian waters

1992 ◽  
Vol 43 (1) ◽  
pp. 195 ◽  
Author(s):  
TI Walker
Keyword(s):  
Sex Ratio ◽  
Simulation Model ◽  
Mesh Size ◽  
Fishing Effort ◽  
Probability Density Distribution ◽  
Natural Mortality ◽  
Sex Ratio At Birth ◽  
Gill Nets ◽  
Gill Net ◽  
Number Of Births

A dynamic pool simulation model is derived and applied to the gummy shark stock of the southern shark fishery. Inputs to the model are fishing effort reported by fishers for hooks and for gill-nets with mesh sizes of 6 inches (152 mm), 7 inches (178 mm) and 8 inches (203 mm) along with estimates for growth, natural mortality, catchability, hook and gill-net mesh selectivity, size at maturity and fecundity of females, sex ratio at birth, and length-weight relationships. Growth is described by the von Bertalanffy equation; hook selectivity is constant with length for sharks recruited to the fishery; gill-net selectivity is based on the probability density distribution of the gamma function where selectivity varies with the mesh size of the gill-nets and the length of the sharks; number of births is related to the proportion of females mature at each length, and the relationship between number of births and maternal weight is linear; parturition is annual and time is standardized so that parturition occurs at the beginning of each year; sex ratio at birth is based on observations of a 1: 1 sex ratio of embryos; and allometric weight-length is based on the power curve. Natural mortality of recruits, catchability, reproduction and growth parameters are held constant, but density-dependent natural mortality of prerecruits is varied in proportion to stock abundance. The model is used to simulate effects of historical longline fishing effort and gill-net fishing effort for each mesh size on stock biomass, numbers of sharks in the stock, and numbers of births. The performance of the model is evaluated by comparing simulated annual catches and the simulated mean weight of sharks captured with annual catches reported by the fishers and the mean weight of sharks sampled in commercial landings. Uncertainties surrounding estimates of some of the parameters are discussed. Notwithstanding its shortcomings, the model indicates that the stock of gummy shark has been severely reduced and is in danger of further depletion unless immediate action is taken to reduce the commercial catch.

scholarly journals Numerical Model of Fish Exploitation – structure and application

2019 ◽  
Vol 27 (2) ◽  
pp. 86-101
Author(s):  
Paweł Buras ◽  
Wiesław Wiśniewolski
Keyword(s):  
Numerical Model ◽  
Simulation Models ◽  
Fishing Effort ◽  
Natural Mortality ◽  
Recreational Fisheries ◽  
Fisheries Resources ◽  
Fish Exploitation ◽  
The Common ◽  
Common Bream ◽  
The Impact

Abstract Fisheries simulation models are tools used for forecasting the effects of exploitation and determining the directions of managing fisheries resources. The Numerical Model of Fish Exploitation (NMFE) and its capabilities were tested on a population of common bream, Abramis brama (L.) in a dam reservoir that is exploited by commercial and recreational fisheries. Based on the designated population parameters of N0, Fij, Mi, and ei and the size and structure of the common bream population in the reservoir, the model was used to examine hypothetical simulation variants of changes in fishing intensity E1 with nets and rods, changes in fishing intensity based on actual fishing effort with nets, changes in natural mortality, changes in the size of fish caught, and the impact of this on the size of the resources. Initial catches with nets and rods were calculated. Increasing fishing effort did not translate proportionally to increased catches, and the function was curvilinear. The results of simulations that reduced the intensity of fishing with nets and decreased catch sizes concurred with data from actual catches. Simulations of changes in natural mortality had various effects on the size of catches. Reducing parameter M did not impact the level of catches, while increasing parameter M reduced the size of catches significantly.

Interpretation of the Sedimentology and Morphology of Perched Glaciolacustrine Deltas on the Flanks of the Lake Superior Basin, Thunder Bay, Ontario

1994 ◽  
Vol 20 (2) ◽  
pp. 390-406 ◽  
Author(s):  
Brian A.M. Phillips ◽  
Phillip W. Fralick
Keyword(s):  
Lake Superior ◽  
Thunder Bay

Parameters for a Roll On-Roll Off Marine Intermodal Service on Lake Superior

2003 ◽  
Vol 1820 (1) ◽  
pp. 46-54
Author(s):  
Richard D. Stewart ◽  
Terry LaVoie ◽  
Nathan Shutes
Keyword(s):  
Lake Superior ◽  
The United States ◽  
Future Application ◽  
Spreadsheet Model ◽  
Thunder Bay ◽  
Application Potential ◽  
Terminal Design ◽  
The Baltic ◽  
Terminal Operations ◽  
Cost Factors

The feasibility of reestablishing roll on–roll off (RO–RO) service linking Thunder Bay, Ontario, and the Twin Ports of Duluth, Minnesota, and Superior, Wisconsin, was examined. An analysis of similar services both on the Great Lakes and overseas was undertaken. Previous operations on the same route on Lake Superior and short sea service in the Baltic region were analyzed, and the attributes of an appropriate vessel type, such as ice strengthened scantlings and adequate speeds, were determined. A route schedule for a typical vessel was developed. A profile of a suitable vessel was prepared, and the market availability of the vessels was assessed. Issues in terminal design and operation were applied to potential docks in the ports of call to determine the adequacy of shoreside facilities. Cost factors for vessel operations and terminal operations were determined, and a spreadsheet model was developed for future application. Potential revenue streams from vessel and terminal operations were also explored. Revenue generators included day passengers as well as trailers and containers. The feasibility of linking the RO–RO service to a larger intermodal system serving Canada and the United States was also assessed.

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