scholarly journals A method to predict the reproductive cycle of the striped venus clam Chamelea gallina based on the influence of environmental factors: Application in its fishery management

2022 ◽  
Vol 245 ◽  
pp. 106133
Author(s):  
Inés Martínez-Pita ◽  
Oscar Moreno
2016 ◽  
Vol 73 (4) ◽  
pp. 1033-1041 ◽  
Author(s):  
Margarita María Rincón ◽  
John D. Mumford ◽  
Polina Levontin ◽  
Adrian W. Leach ◽  
Javier Ruiz

Abstract Anchovy population dynamics in the Gulf of Cádiz are governed by environmental processes. Sea surface temperature, intense easterly winds, and discharges from the Guadalquivir River have been identified as key factors determining early life stage mortality in this anchovy stock. We have constructed an environment-based recruitment model that simulates the abundance of juveniles under alternative parameters representing plausible biological hypotheses. We are able to evaluate how modelling environment-based recruitment can affect stock assessment and how responding to environmental information can benefit fishery management to allow greater average catch levels through the application of harvest control rules (HCRs) based on environmental conditions. While the environment-based rules generally increase allowable catch levels the variance in catch levels also increases, detracting from the improved value based only on average yield. In addition to changes in revenue, the probability of stock collapse is also reduced by using environmental factors in HCRs. To assess the value of these management systems we simulate a notional insurance scheme, which applies a value to both average yields and uncertainty. The value of the information-driven rules can be determined by comparing the relevant premiums payable for equal levels of insurance cover on revenue within each specific management regime. We demonstrate the net value of incorporating environmental factors in the management of anchovies in the Gulf of Cádiz despite the increased variability in revenue. This could be an effective method to describe outcomes for both commercial fisheries and ecosystem management policies, and as a guide to management of other species whose dynamics are predictable based on in-season observations.


2017 ◽  
Vol 80 (9) ◽  
pp. 1429-1435 ◽  
Author(s):  
Giulia Tabanelli ◽  
Chiara Montanari ◽  
Aldo Gardini ◽  
Mirko Maffei ◽  
Chiara Prioli ◽  
...  

ABSTRACT The aim of this work was to evaluate the microbiological quality of striped venus clams (Chamelea gallina L.) harvested in the north Adriatic Sea during an 8-year monitoring period. A total of 387 samples were analyzed to assess the presence of Escherichia coli. Environmental parameters (salinity, pH, dissolved oxygen, seawater temperature, and freshwater outflow) were collected to find out a possible relationship between the E. coli counts and environmental factors. The results evidenced that the microbiological quality of the clams was good, with only about 5% of the samples not complying with European and Italian regulations for this product, that is, with E. coli counts higher than 230 most probable number (MPN) per 100 g of flesh and intravalvar liquid. Statistical analyses revealed a relationship between microbial contamination and the season and water temperature, probably due to the difference in the filtering activity of the mollusks. However, the main factor affecting the E. coli concentration in the clams turned out to be the flow rate of Marecchia, the major river that reaches the sea in the area of harvesting. In fact, a model fitted to evaluate the probability of finding a higher E. coli count in relation to the environmental parameters evidenced that it was an increase of the level of the Marecchia led to a higher probability of elevated E. coli contamination. This result could be explained by the higher supply of both nutrients and coliforms (including E. coli) when the river is higher and by the anthropogenic characteristics of the lands crossed by the river.


Author(s):  
Norma Berenice Cruz-Cano ◽  
Uriel Ángel Sánchez-Rivera ◽  
Carmen Álvarez-Rodríguez ◽  
Rodrigo Dávila-Govantes ◽  
Mario Cárdenas-León ◽  
...  

2011 ◽  
Vol 68 (6) ◽  
pp. 1155-1164 ◽  
Author(s):  
Phillip R. Mundy ◽  
Danielle F. Evenson

Abstract Mundy, P. R., and Evenson, D. F. 2011. Environmental controls of phenology of high-latitude Chinook salmon populations of the Yukon River, North America, with application to fishery management. – ICES Journal of Marine Science, 68: 1155–1164. Phenologies of a number of anadromous fish species have been demonstrated to vary in concert with environmental factors that change with global warming, such as water and air temperatures. Anadromous fishery managers will need advice from models of phenology, or migratory timing, as functions of environmental factors in those harvest areas where annual migratory timing can vary sharply. Such models are also necessary to advise fishery managers on how and when global warming projections of the IPCC model ensemble should be factored into regulatory decisions. Specifically, we demonstrate that the annual timing of marine exit of Yukon River Chinook salmon (Oncorhynchus tshawytscha) at 63°N 165°W for 1961–2009 varied in close concert with modelled sea surface temperature, air temperature, and sea ice cover. The best linear model for 1961–2009 combines sea surface and air temperatures to explain 59% of the annual variability in migratory timing (ice cover is available only for 1970–2009). Changes in phenology of high-latitude Chinook salmon are expected in response to global warming. As average temperatures increase, the frequency of earlier migrations is expected to increase, making management of the fishery more challenging.


1982 ◽  
Vol 33 (4) ◽  
pp. 649 ◽  
Author(s):  
RL Dunstone

The environmental factors which control the reproductive cycle of jojoba (Simmondsia chinensis [Link] Schneider), were studied under controlled conditions. Plants were placed under a warm pretreatment temperature which resulted in the growth of new shoots bearing dormant flower buds. The plants were later moved to lower treatment temperatures which have been shown to break flower bud dormancy. Pretreatment temperature affected the percentage of nodes which produced flower buds. Both the pretreatment and the treatment temperature affected flowering percentage, there being an optimum pretreatment effect at 30/25�C day/night temperatures. Flowering percentage responded to absolute treatment temperature rather than to the drop in temperature from pretreatment to treatment. Flowering percentage increased with decrease in treatment temperature down to 15/10�C (male clone) and 12/7�C (female clone). The lowest pretreatment-treatment temperature combination was associated with the production of female flower parts on the male inflorescences.


2010 ◽  
Vol 31 (1) ◽  
pp. 117-126 ◽  
Author(s):  
Sandra Martelotte ◽  
Carlos Rocha ◽  
Mara Cíntia Kiefer ◽  
Monique Van Sluys

AbstractLizards exhibit a wide array of reproductive strategies. For tropical lizards, a single reproductive pattern is not evident, and the actual determinants of seasonality in reproduction remain unclear. Tropidurus torquatus is the most widely distributed species of the genus in Brazil and occurs in coastal and inland areas, and in islands off the Brazilian shore. In this study, we examine the reproductive cycle of T. torquatus at a coastal area in Rio de Janeiro State, southeastern Brazil. We analysed the reproductive cycle of T. torquatus from one coastal population to evaluate how reproduction is affected by local environmental factors (rainfall), and we also compared reproductive parameters of T. torquatus between two time periods (15 years apart) at the same locality. Tropidurus torquatus reproduces from the beginning of the dry season to the middle of the rainy season, even considering the two time periods. Reproductive season was similar between the coastal and inland populations suggesting that local environmental factors play a less important role in regulating the duration of the reproductive cycle of these lizards.


2000 ◽  
Vol 60 (3) ◽  
pp. 483-491 ◽  
Author(s):  
A. L. D. REIGADA ◽  
M. L. NEGREIROS-FRANSOZO

This study aimed to analyze the reproductive cycle of the crab Hepatus pudibundus (Herbst, 1785). The crabs were collected in Ubatuba, SP (23°26'S and 45°02'W) monthly from the July, 1992 to June, 1993. Samplings were performed with an "otter trawl". In the laboratory the crabs were numbered, sexed and measured for their maximum carapace width. The gonad developmental stage and the moult stage were also macroscopically registered. In all sampled months ovigerous females and crabs in both sexes with developed gonad were observed. Moult activity in all size classes was verified. Such fact indicates that this species can suffer moult process after their maturity. In despite of temperature being pointed a one of the most important ecological factor in the reproductive biology of aquatic animals, it was verified any relation between water temperature and ovigerous ratio. The oscillations of the environmental factors in the Ubatuba region sea probably were not enough to alter the continuity of the physiological processes related to H. pudibundus reproduction.


2017 ◽  
Vol 6 (3) ◽  
Author(s):  
Cesare Ciccarelli ◽  
Angela Marisa Semeraro ◽  
Melina Leinoudi ◽  
Vittoria Di Trani ◽  
Sandra Murru ◽  
...  

Consumption of bivalve shellfish harvested from water contaminated with sewage pollution presents a risk of human infections and targeting control measures require a good understanding of environmental factors influencing the transport and the fate of faecal contaminants within the hydrological catchments. Although there has been extensive development of regression models, the point of this paper, focused on the relationship between rainfall events and concentrations of <em>Escherichia coli</em> monitored in clams, was the use of a Bayesian approach, by the Bayes Factor. The study was conducted on clams harvested from the south coast of Marche Region (Italy), a coastal area impacted by continuous treated effluents, intermittent rainfalldependent untreated sewage spillage - as a consequence of stormwater overflowing - and rivers with an ephemeral flow regime. The work compared the different interpretation criteria of Bayes Factor, confirmed that <em>E. coli</em> concentrations in clams from the studied area varied in correlation with rainfall events, and demonstrated the effectiveness of Bayes Factor in the assessment of shellfish quality in coastal marine waters. However, it suggested that further investigations would be warranted to determine which environmental factors provide the better basis for accurate and timely predictions. Furthermore the gathered data could be useful, to the local authorities of Marche Region, in the definition of flexible monitoring programmes, taking into account the atmospheric events that could affect the correct functioning of sewage managing systems and the flow of tributary rivers.


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