Non‐native Pike Killifish do not exert Predatory Pressure on Juvenile Common Snook

Author(s):  
Geoffrey H. Smith ◽  
Debra J. Murie
Diversity ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 347
Author(s):  
Jazmín Terán-Martínez ◽  
Rocío Rodiles-Hernández ◽  
Marco A. A. Garduño-Sánchez ◽  
Claudia Patricia Ornelas-García

The common snook is one of the most abundant and economically important species in the Usumacinta basin in the Gulf of Mexico, which has led to overfishing, threatening their populations. The main goal of the present study was to assess the genetic diversity and structure of the common snook along the Usumacinta River in order to understand the population dynamics and conservation status of the species. We characterized two mitochondrial markers (mtCox1 and mtCytb) and 11 microsatellites in the Usumacinta basin, which was divided into three zones: rainforest, floodplain and river delta. The mitochondrial data showed very low diversity, showing some haplotypic diversity differences between the rainforest and delta zones. In contrast, we consistently recovered two genetic clusters in the Usumacinta River basin with the nuclear data in both the DAPC and STRUCTURE analyses. These results were consistent with the AMOVA analyses, which showed significant differences among the genetic clusters previously recovered by DAPC and STRUCTURE. In terms of diversity distribution, the floodplain zone corresponded to the most diverse zone according to the mitochondrial and nuclear data, suggesting that this is a transition zone in the basin. Our results support the relevance of the molecular characterization and monitoring of the fishery resources at the Usumacinta River to better understand their connectivity, which could help in their conservation and management.


2019 ◽  
Vol 79 (3) ◽  
pp. 505-509 ◽  
Author(s):  
L. A. Herrera ◽  
V. V. Kuhnen ◽  
E. G. Sanches

Abstract Salt water recirculation systems using automatic feeders are a new frontier for marine aquaculture. It is possible to decrease the vulnerability of the traditional fish farming in open systems and reduce wasteful feeding and discharge of effluents, as well as increase the economic returns. An experiment with common snook fingerings (4.31 ± 1.42 g and 8.4 ± 1.0 cm) was performed. Three feeding treatments were evaluated: six, twelve and eighteen feeding times per day. Each treatment had three replications. Among the three tested frequencies (fed 6, 12 and 18 times a day), the feeding frequency of 12 times per day (every two hours) showed the best values of the parameters evaluated for production performance. The final weight values, condition factor, specific growth rate and daily weight gain of the treatment 12 feeding times per day were all significantly higher than the lower and higher frequencies. Our results demonstrate that high feeding frequency is not synonymous of higher performance, but is extremely necessary to find out the best range for the target species. Besides, this relationship between feeding frequency and growth performance might change over weight range. Therefore, future studies should address higher weight ranges for comparison to our results.


2019 ◽  
Vol 48 ◽  
Author(s):  
Ricardo Luís Mendes de Oliveira ◽  
Leilane Bruna Gomes dos Santos ◽  
Nelson Gomes da Silva Neto ◽  
Scarlatt Paloma Alves da Silva ◽  
Felipe dos Santos Silva ◽  
...  

<i>Abstract</i>.—In designing research programs, scientists may constrain development of sequential hypotheses because of perceptions about logistical constraints to using new technologies in monitoring or experimental design. Using trusted, familiar methods can supersede asking which hypotheses would have the greatest impact and what method(s) are required to test them. To help maintain a ‘problem-oriented’ approach, rather than a ‘methods oriented’ one, we could strive to remain aware of new innovations and applications in research; this is particularly so for tagging technology, when new methods emerge. Research enabled by recent innovations can be incorporated through collaborations with other scientists or by working directly with vendors to implement and refine new tag technologies and applications. Some tagging studies can be improved by using multiple marking methods (e.g. see recent applications of various tag technologies with common snook <i>Centropomus undecimalis </i>and red drum <i>Sciaenops ocellatus </i>in Florida to evaluate recruitment, mortality, and habitat use of different life stages; Adams et al. 2006; Bennett 2006; Marcinkiewicz, 2007; Brennan et al. 2008; Tringali et al. 2008). Here we consider a few case studies that have implemented a variety of tagging methods to explore poorly understood factors that mediate growth and survival and the effectiveness of hatchery releases to help replenish depleted marine fish stocks.


2019 ◽  
Vol 51 (2) ◽  
pp. 844-847
Author(s):  
Ron Hans ◽  
Ryan Schloesser ◽  
Nathan Brennan ◽  
Flavio Ribeiro ◽  
Kevan L. Main

2004 ◽  
Vol 35 (3) ◽  
pp. 278-288 ◽  
Author(s):  
T R Tiersch ◽  
W R Wayman ◽  
D P Skapura ◽  
C L Neidig ◽  
H J Grier

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Lennart M. van Maldegem ◽  
Pierre Sansjofre ◽  
Johan W. H. Weijers ◽  
Klaus Wolkenstein ◽  
Paul K. Strother ◽  
...  

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