Latin American Journal of Aquatic Research

ABSTRACT The aim of this study was a detection of different populations of Pacific white shrimp (Penaeus vannamei Boone, 1931) farmed broodstocks and to determine their genetic indexes in hatchery centers of Bushehr province. DNA was extracted from the muscle tissue of 30 broodstocks of 11 stocks using a commercial kit. The repeated sequences were amplified using ten specific primers by PCR in the Iranian Shrimp Center. The results showed that the number of alleles was 4.5-5.5 in the studied stocks. The most allele frequency was observed in the farmed broad stocks of the third stock in the H2 hatchery center, 5.2 ± 0/359. Also, the average of observed heterozygosity in the farmed broad stocks of the second stock in the H5 hatchery center obtained 0.669 ± 0.152, more than other stocks in all centers. Genetics indexes of the farmed broad stocks of the third stock in the H2 hatchery center were increased compared with other stocks in Bucher province. The inbreeding coefficients of the first stocks in the H1 and H3 hatchery centers were significantly more than others, respectively, 0.595 ± 0.105 and 0.547 ± 0.145. The increased inbreeding coefficients of the farmed broad stocks in these stocks can be referred to due to the small size of the founder population and biased selection programs. However, this amount is acceptable according to the information of the other hatchery centers in Bushehr province and other countries. Moreover, it was concluded that broodstock with higher diversity should be used to increase the genetic indicators in the hatchery centers.

ABSTRACT Callao Bay is strategically important for the industrial and tourist sector, serving as a recreational space for a large part of the population of Chalaca. However, even so, it permanently receives discharges of effluents, chemical products, and residues from oil refineries, hydrocarbons, and domestic and agricultural residues. The objective of this research is to evaluate biochemical indicators in fish against contaminants in the coastal area of Callao, Peru. The seasonal criterion (collections in autumn, spring, summer, and winter) and the spatial criterion (collections at four points along the coastal zone of Callao) were considered. Isacia conceptionis and Odontesthes regia showed relatively high concentration values of the enzyme alanine aminotransferase (ALT). Specifically, ALT is an enzyme used to assess liver function. Sciaena deliciosa showed high levels of alkaline phosphatase (ALP) in the liver but low values of aspartate aminotransferase (AST) and ALT. In addition, ALP is an indicator of renal impairment; in saltwater fish, its increase may be related to the increase in water salinity. The fish with the highest trophic level among the marine fish analyzed was O. regia. This fish presented the lowest values of ALP in the liver and muscle ALP and AChE (acetylcholinesterase) in the liver and the highest values for AST. S. deliciosa and O. regia are species that can be used in environmental biomonitoring, showing variation to the biomarkers studied because they have shown changes in the values of biochemical markers, mainly AChE of the brain and muscle, and in the protein concentrations of muscle, brain, and liver between seasons and sampling points in Callao Bay. It is concluded that the marine fish models evaluated are very useful in assessing contamination in Callao Bay.

ABSTRACT Escaped salmonids are considered among the most serious threats to the aquatic environment. One hundred and nine escape incidents were reported in Chile from 2004-2021, representing some 8.53 million escaped salmonids. Of this total, 5.73 million were Atlantic salmon Salmo salar (67.2%), 0.83 million coho salmon Oncorhynchus kisutch (9.8%), and 1.96 million were rainbow trout O. mykiss (23.0%). It is estimated that 70.1% of the escaped salmonids were recorded in the Los Lagos Region, 23% in the Aysén Region, and 4.6% in the Magallanes Region. In total, 80.5% of the escapes were recorded from seawater facilities, while freshwater units accounted for 19.5%. The highest percentage of escaped salmon recorded in seawater over 2004-2021 was 1.71% of harvested salmonids in 2013. Some 39.5% of the escapes in 2015-2021 were attributed to rupturing of net cages, mainly due to adverse climatic conditions. The additional regulations introduced in 2020 by the Chilean authority, has helped to minimize the escape of farmed salmonids. As a consequence, just one escape event was reported in 2021, corresponding to 3.85% of the total number of escapees recorded from 2004-2021.

ABSTRACT The biological importance of rhizosphere sediment-associated fungi in mangroves is poorly understood, especially when they are affected by high salinity and anaerobiosis in disturbed areas. This study evaluated the fungal diversity in the rhizosphere sediments of three mangrove species associated with three conservation conditions of mangrove forests in preserved, semi-preserved, and deteriorated areas. In addition, fungal bioactivity was correlated to the fungal diversity found in mangrove species from each area. We isolated 50 fungal strains belonging to three phyla, seven classes, and 10 orders. The fungal diversity was higher in the preserved area (H’ = 2.22) than in the semi-preserved (H’ = 1.73) and deteriorated areas (H’ = 1.68); the redundancy analysis showed a tendency of fungal accumulation towards the rhizosphere of Rhizophora mangle and Avicennia germinans in the preserved and semi-preserved areas. In addition, the redundancy analysis showed that 10 bioactive fungi genera tended to accumulate on the rhizosphere of R. mangle and A. germinans in the preserved and semi-preserved areas. The preserved area is related to the semi-preserved area, with a 28% Jaccard similarity coefficient. The diversity and bioactivity of the isolated fungi encourage the need to conserve and restore mangrove ecosystems considering their current and potential services, such as bioprospecting new pharmacological compounds.

ABSTRACT The Northeastern Pacific (NEP) population of white sharks (Carcharodon carcharias) is genetically distinct from the rest of the world. This uniqueness results from adult fidelity to central California and Guadalupe Island aggregations sites. The strong mitochondrial genetic structure between the white sharks of central California and Guadalupe Island is also present, which indicates female philopatry. To date, few studies using nuclear DNA have found evidence of genetic patterns in the NEP white shark population, which could indicate that these sharks exhibit sex-biased dispersal. In this study, we evaluated the genetic structure, connectivity, and genetic diversity of NEP white sharks using samples from the southern California Bight (SCB), Baja California (including Sebastian Vizcaino Bay), the Gulf of California, and Guadalupe Island (GI) using nDNA (i.e. microsatellite loci). A total of five loci were successfully genotyped in 54 individuals. The patterns found in this study indicated low levels of genetic diversity among all localities (observed heterozygosity: Ho = 0.47), likely due to a founder effect. A slight genetic structure was present for NEP localities in this study (FST = 0.045, P = 0.0001), mainly identified between the SCB and GI locations. A sibship assignment analysis indicated low and moderate probabilities of full- and half-siblings between white shark juveniles from coastal areas, suggesting a high degree of connectivity between nursery areas in the NEP. Our results suggest that juveniles can mask the genetic structure in coastal zones.