Black Bass Diversity: Multidisciplinary Science for Conservation

2015 ◽  
Keyword(s):  
Mixed Model ◽  
Micropterus Salmoides ◽  
Underlying Mechanism ◽  
Treated Wastewater ◽  
Fish Length ◽  
Catch Per Unit Effort ◽  
Explanatory Factors ◽  
Black Bass ◽  
Intersex Condition ◽  
Catch Rates

<em>Abstract</em>.—Reports of testicular oocytes (intersex) in fish are increasing worldwide. Intersex is often associated with estrogens in treated wastewater effluents, but few studies have explored other potentially explanatory factors. Our recent survey of intersex Largemouth Bass <em>Micropterus salmoides</em> in 11 impoundments across Georgia, USA found high incidence (>80%) of intersex fish in some impoundments but none in others. To explore factors associated with intersex in the impoundments, which did not receive wastewater, we examined potential predictor variables that varied among the levels of individual fish, impoundment, or landscape in a binomial mixed-model regression approach. Our model indicated effects of fish length, catch per unit effort (an index of fish density), and impoundment, which was the strongest effect. The probability of intersex was highest in smaller fish from impoundments with the highest catch rates. The underlying mechanism(s) for the impoundment effect remain unclear, but we hypothesize that estrogens excreted by high densities of fish and cyanobacteria may influence intersex. Additional studies are needed to understand the long-term population implications of intersex and the role of other biological and environmental factors, particularly at the impoundment level, in development of the intersex condition.

Black Bass Diversity: Multidisciplinary Science for Conservation

2015 ◽  
Keyword(s):  
Largemouth Bass ◽  
Micropterus Salmoides ◽  
The United States ◽  
Environmental Drivers ◽  
Minimum Length ◽  
Catch And Release ◽  
Black Bass ◽  
Intensively Managed ◽  
Catch Rates ◽  
Sport Fish

<em>Abstract</em>.—Largemouth Bass (LMB) <em>Micropterus salmoides</em> is one of the most popular sport fish in the United States and is intensively managed across much of its range. Beginning in 1989, Wisconsin implemented more restrictive harvest regulations for LMB, including greater minimum length limits, reduced bag limits, and a catch-and-release-only season during the spawning period across much of northern Wisconsin. We tested for trends in LMB relative abundance, growth, and angler catch and harvest in relation to LMB management policies from 1990 to 2011. We also tested for potential sport fish community responses to changes in LMB abundances using Walleye (WAE) <em>Sander vitreus</em> as an example. Angler catch rates and electrofishing catch per unit effort of LMB greater than 8 and 14 in increased significantly statewide. Mean length of age-6 LMB decreased significantly statewide. Release rates of LMB increased from about 80% in 1991 and then plateaued at more than 96% from 2005 to 2011. Concurrent with increases in LMB, adult WAE densities declined in lakes containing LMB. Ongoing research is being conducted to test for interactions between LMB and WAE and to test for additional environmental drivers, such as climate warming, that may be associated with increased LMB abundances. Largemouth Bass abundances have increased in Wisconsin, possibly in response to changes in harvest regulations, angler behavior, and potentially other environmental drivers. These increases in LMB abundances have had negative intraspecific effects on growth and may be negatively affecting WAE stocks. We recommend that management goals for LMB consider intra- and interspecific consequences, particularly in water bodies where multispecies fisheries are desired.

Standardization of bluefin tuna, Thunnus thynnus, catch per unit effort in the baitboat fishery of the Bay of Biscay (Eastern Atlantic)

2003 ◽  
Vol 60 (6) ◽  
pp. 1216-1231 ◽  
Author(s):  
E. Rodríguez-Marín ◽  
H. Arrizabalaga ◽  
M. Ortiz ◽  
C. Rodríguez-Cabello ◽  
G. Moreno ◽  
...  
Keyword(s):  
Mixed Models ◽  
Juvenile Fish ◽  
Bluefin Tuna ◽  
Random Component ◽  
Catch Per Unit Effort ◽  
Age Class ◽  
Explanatory Factors ◽  
Technological Advances ◽  
Coefficients Of Variation ◽  
Catch Rates

Abstract Relative indices of abundance by age class for bluefin tuna from 1975 to 2000 were estimated using generalized linear mixed models. Age class was included as a fixed factor within the model specifications, with the Year×Age interaction as a fixed factor component in order to obtain annual indices by age. Catch and effort data on bluefin tuna were available from two sources, catches by trip, and daily catches from logbooks. Catches were modelled using the delta-lognormal model. The model finally selected included the following explanatory factors: Year, Age, Year×Age, Month, number of Crew, number of Bait Tanks, and with the Year×Month interaction as a random component. Overall, year trends and coefficients of variation were similar from both datasets by age class. In general, the standardization procedure showed that vessel characteristics and technological advances related to fishing have a relatively minor explanatory effect on the observed catch rates of bluefin tuna in the fishery. Neither geographical distribution nor type of bait had an explanatory effect on the observed catch rates. The 1994 cohort stands out as an exceptionally large year class; it can be followed through the standardized series. This standardized catch rate index at age of bluefin tuna is the most complete yet available and is the only one currently used for juvenile fish in calibrating population models to evaluate the Eastern Atlantic and Mediterranean stock. It is particularly valuable because, apart from improvements in electronic technology, there are no changes in the method of exploitation during the entire series.

Fish and invertebrate by-catch in the crab pot fishery in the Isle of Man, Irish Sea

2017 ◽  
Vol 98 (8) ◽  
pp. 2099-2111
Author(s):  
Fikret Öndes ◽  
Michel J. Kaiser ◽  
Lee G. Murray
Keyword(s):  
Irish Sea ◽  
Target Species ◽  
Catch Per Unit Effort ◽  
Isle Of Man ◽  
Ecosystem Effects ◽  
By Catch ◽  
Catch Rates ◽  
Taxonomic Groups ◽  
Catch Composition ◽  
Autumn And Winter

Baited trap or pot fisheries are considered to have relatively few wider ecosystem effects on the marine environment, particularly when compared with towed mobile fishing gear. However, this assumption is rarely tested in the field. This study aimed to determine the composition of non-target species that occur in crustacean pots and to assess spatial and temporal differences in catches in the waters around the Isle of Man, Irish Sea. The data were collected using fishery independent surveys and a questionnaire study. Based on fishery independent surveys, a total of five taxonomic groups and 43 species occurred as by-catch. The dominant by-catch species was velvet crab Necora puber. The by-catch per unit effort (BPUE) for all of the non-target species was low particularly in comparison to towed bottom gear fisheries around the Isle of Man. BPUE of species composition varied considerably between different locations around the Isle of Man. The results of both the fishery independent and questionnaire data suggested that the by-catch rates varied with season with peak BPUE occurring in spring which then declined into autumn and winter. By-catch composition did not decrease significantly with an increasing target species catch. Overall, by-catch was low relative to target species catch which may be partially attributable to the use of escape panels in pot fisheries in the Isle of Man.

scholarly journals Occurrence of parasites of the genus Eustrongylides spp. (Nematoda: Dioctophymatidae) in fish caught in Trasimeno lake, Italy

2016 ◽  
Vol 5 (4) ◽  
Author(s):  
Raffaella Branciari ◽  
David Ranucci ◽  
Dino Miraglia ◽  
Andrea Valiani ◽  
Fabrizia Veronesi ◽  
...  
Keyword(s):  
Cyprinus Carpio ◽  
Carassius Auratus ◽  
Micropterus Salmoides ◽  
Abdominal Cavity ◽  
Perca Fluviatilis ◽  
Tinca Tinca ◽  
European Perch ◽  
Black Bass ◽  
Zoonotic Parasites ◽  
Edible Fish

<em>Eustrongylides</em> spp. is considered a freshwater fish zoonotic nematode. In the present study, the prevalence of <em>Eustrongylides</em> spp. in six edible fish (European perch - <em>Perca fluviatilis</em>, goldfish - <em>Carassius auratus</em>, largemouth black bass - <em>Micropterus salmoides</em>, tench- <em>Tinca tinca</em>, carp - <em>Cyprinus carpio</em> and sand smelt - Atherina boyeri) of Trasimeno lake was surveyed. The investigations were conducted from October 2014 to September 2015 and 384 specimens per species for each season were caught in Trasimeno lake and examined for the presence of larvae in the abdominal cavity and muscle. The presence of nematodes in the abdominal cavity and musculature was revealed in three fish species. The prevalence of Eustrongylides spp. infection was 6.84, 1.89 and 0.13% in perch, largemouth black bass and sand smelt, respectively. The number of parasites per fish was only one in largemouth black bass and sand smelt and ranged from one up to three in perch. This study states that the European perch, largemouth black bass and sand smelt of Trasimeno lake are infected with zoonotic parasites; therefore, food business operators have to take appropriate measures to guarantee the health of consumers.

Aspects of the fishery, maturation and net selectivity of the wedge sole (Dicologoglossa cuneata) off south-western Iberia: implications for fishery management

2009 ◽  
Vol 90 (7) ◽  
pp. 1465-1474 ◽  
Author(s):  
Miguel Neves Santos ◽  
Pedro Gil Lino
Keyword(s):  
Fishery Management ◽  
River Mouth ◽  
Mesh Size ◽  
Scientific Basis ◽  
Catch Per Unit Effort ◽  
Important Species ◽  
Gill Net ◽  
Catch Rates ◽  
Log Normal ◽  
First Maturity

The wedge sole (Dicologoglossa cuneata, Moreau 1881) is a commercially important species for the artisanal fleet operating off the south-western Iberian Peninsula. During 2004 and 2005 a study was undertaken aiming to provide a scientific basis for management. Data collection included information on aspects of the fishery, spawning season, size at first maturity, tangle and gill-net selectivity. Seven nominal mesh sizes were used (40, 45 and 50 mm tangle nets and 40, 50, 60 and 70 mm gill-nets). Spawning lasts from December to June, with peaks in March and May. Length at first maturity for females was estimated at 18.5 cm. Catch rates decreased sharply with increasing mesh size, with tangle nets providing the highest yields. The log-normal selectivity model provided the best fit for specimens that were wedged. The higher catch-per-unit-effort of the smaller mesh sizes and the modal length of the fitted selectivity curve being below the size-at-maturity for wedge sole, suggests that the 50 mm nominal mesh size tangle net is the most appropriate for ensuring the fishery sustainability. Nevertheless, the minimum legal size should increase to at least 18 cm and a time–area closure should be implemented off the Guadiana River mouth.

scholarly journals Standardizing catch rates: is logbook information by itself enough?

2008 ◽  
Vol 65 (2) ◽  
pp. 255-266 ◽  
Author(s):  
J. Bishop ◽  
W. N. Venables ◽  
C. M. Dichmont ◽  
D. J. Sterling
Keyword(s):  
Relative Abundance ◽  
Prediction Models ◽  
Expert Knowledge ◽  
External Information ◽  
Linear Regression Models ◽  
Catch Per Unit Effort ◽  
Estimation Model ◽  
Catch Rates ◽  
Logbook Data ◽  
Estimation Models

Abstract Bishop, J., Venables, W. N., Dichmont, C. M., and Sterling, D. J. 2008. Standardizing catch rates: is logbook information by itself enough? – ICES Journal of Marine Science, 65: 255–266. The goal of the work was to maximize the accuracy of standardized catch per unit effort as an index of relative abundance. Linear regression models were fitted to daily logbook data from a multispecies penaeid trawl fishery in which within-vessel changes in efficiency are common. Two model-fitting strategies were compared. The predictive strategy focused on maximizing the explained variance, and the estimation strategy on finding realistic coefficients for important components of changing catchability. Realistic values could not always be obtained, because the regression factors were not orthogonal, and data on the presence of technology were sometimes unreliable or systematically incomplete. It was not possible to separate fishing power from abundance by analysing logbook data alone; it was necessary to incorporate external information within the standardization model. Therefore, the resultant estimation models incorporated external information and expert knowledge by offsets. There was no single best estimation model. Instead, a series of models provided an envelope of possible changes in relative fishing power and prawn abundance since 1970. Compared with the prediction models, the estimation models revealed different trends in relative fishing power and relative abundance.

scholarly journals Spatiotemporal variation in size-structured populations using fishery data: an application to shortfin mako (Isurus oxyrinchus) in the Pacific Ocean

2017 ◽  
Vol 74 (11) ◽  
pp. 1765-1780 ◽  
Author(s):  
Mikihiko Kai ◽  
James T. Thorson ◽  
Kevin R. Piner ◽  
Mark N. Maunder
Keyword(s):  
Coastal Waters ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Marine Species ◽  
Structured Populations ◽  
Spatiotemporal Model ◽  
The North ◽  
Isurus Oxyrinchus ◽  
Shortfin Mako ◽  
Catch Rates

We develop a length-disaggregated, spatiotemporal, delta-generalized linear mixed model (GLMM) and apply the method to fishery-dependent catch rates of shortfin mako sharks (Isurus oxyrinchus) in the North Pacific. The spatiotemporal model may provide an improvement over conventional time-series and spatially stratified models by yielding more precise and biologically interpretable estimates of abundance. Including length data may provide additional information to better understand life history and habitat partitioning for marine species. Nominal catch rates were standardized using a GLMM framework with spatiotemporal and length composition data. The best-fitting model showed that most hotspots for “immature” shortfin mako occurred in the coastal waters of Japan, while hotspots for “subadult and adult” occurred in the offshore or coastal waters of Japan. We also found that size-specific catch rates provide an indication that there has been a recent increasing trend in stock abundance since 2008.

scholarly journals Growth and mortality of black bass, Micropterus salmoides (Pisces, Centrachidae; Lacapède, 1802) in a reservoir in southern Brazil

2005 ◽  
Vol 65 (2) ◽  
pp. 363-369 ◽  
Author(s):  
U. H. Schulz ◽  
M. E. Leal
Keyword(s):  
Micropterus Salmoides ◽  
Scientific Information ◽  
Fish Fauna ◽  
Fish Diversity ◽  
First Year ◽  
Southern Brazil ◽  
Small Reservoir ◽  
Long Time ◽  
Black Bass ◽  
Aquaculture Facilities

The black bass, Micropterus salmoides, was introduced to Brazil from North America in 1922. Since then the species has been reared in aquaculture facilities intended to stock reservoirs as additions to native stocks available for angling. At present no scientific information on the biology of black bass in Brazilian waters is available. Since black bass dispersion may cause severe impacts on native Brazilian fish fauna, information on the basic biological parameters of this species is necessary. The objective of the present study is to provide information on the growth, age structure, and mortality of the species in a small reservoir in southern Brazil, where the species reproduces regularly. Based on scale readings, the von Bertalanffy growth curve was calculated and compared to the length-frequency distribution of the population. Both methods showed similar results. Maximum length was about 44 cm. The mean length at the end of the first year was 23.1 cm (s.d. = 13.88); at that of the second, 37.3 cm (s.d. = 12.52); and 41.4 cm (s.d. = 9.92) at the third. Oldest fish were three years old. The growth performance index ø' was 3.28 cm year-1. Mortality increased from 0.16 year-1 between the first and the second cohort, to 0.8 year-1 between the second and third. The results show that black bass in Brazil grows faster than in its area of origin, but longevity is shorter and body shape, stouter. The cause of high mortality at a relatively early age may be connected with the loss of genetic diversity due to inbreeding of the Brazilian stocks, which originated from few introduced individuals a long time ago. The fact that black bass reproduces in reservoirs and grows rapidly may be considered a threat to conserving fish diversity in Brazilian ecosystems.

scholarly journals Walleye recruitment success is less resilient to warming water temperatures in lakes with abundant largemouth bass populations

2018 ◽  
Vol 75 (1) ◽  
pp. 106-115 ◽  
Author(s):  
Gretchen J.A. Hansen ◽  
Stephen R. Midway ◽  
Tyler Wagner
Keyword(s):  
Largemouth Bass ◽  
Micropterus Salmoides ◽  
Degree Days ◽  
Large Lakes ◽  
Recruitment Success ◽  
Annual Water ◽  
Catch Rates ◽  
The Relationship ◽  
Annual Water Temperature ◽  
Specific Food

Lakes respond heterogeneously to climate, with implications for fisheries management. We analyzed walleye (Sander vitreus) recruitment to age-0 in 359 lakes in Wisconsin, USA, to (i) quantify the relationship between annual water temperature degree days (DD) and walleye recruitment success and (ii) identify the influence of lake characteristics — area, conductivity, largemouth bass (Micropterus salmoides) catch rates, and mean DD — on this relationship. The relationship between walleye recruitment and annual DD varied among lakes and was not distinguishable from zero overall (posterior mean = −0.11, 90% CI = −0.34, 0.15). DD effects on recruitment were negative in 198 lakes (55%) and positive in 161 (45%). The effect of annual DD was most negative in lakes with high largemouth bass densities, and, on average, the probability of recruitment was highest in large lakes with low largemouth bass densities. Conductivity and mean DD influenced neither recruitment nor the effect of annual DD. Walleye recruitment was most resilient to warming in lakes with few largemouth bass, suggesting that the effects of climate change depend on lake-specific food-web and habitat contexts.

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