scholarly journals Population structure and reproductive biology of the scalloped hammerhead Sphyrna lewini (Carcharhiniformes: Sphyrnidae) caught in artisanal fisheries of Oaxaca, Mexico

2018 ◽  
Vol 28 (3) ◽  
pp. 265-275 ◽  
Author(s):  
María Del Carmen Alejo Plata ◽  
Keyword(s):  
Population Structure ◽  
Reproductive Biology ◽  
Artisanal Fisheries ◽  
Sphyrna Lewini ◽  
Scalloped Hammerhead

Reproductive biology of the scalloped hammerhead (Sphyrna lewini) in the central-eastern Pacific Ocean

2021 ◽  
pp. 1-6
Author(s):  
Colombo Estupiñán-Montaño ◽  
Maribel Carrera-Fernández ◽  
Felipe Galván-Magaña
Keyword(s):  
Pacific Ocean ◽  
Reproductive Biology ◽  
Eastern Pacific ◽  
Eastern Pacific Ocean ◽  
Fishing Activity ◽  
Sphyrna Lewini ◽  
Additional Information ◽  
Scalloped Hammerhead ◽  
Central Eastern ◽  
June July

Abstract There are limited data regarding the reproductive biology of the scalloped hammerhead (Sphyrna lewini) in Ecuadorian waters, which limits the development of appropriate management measures of its populations. A total of 1664 S. lewini specimens were recorded in Manta, Ecuador in 2003–2009. Specimens were caught by local commercial fisheries and measured between 50–310 cm total length (TL). Females were more frequently caught, with a sex ratio of 1M:1.8F. The median size at maturity was 178.1 cm TL for males and 219.4 cm TL for females, which was larger compared with other localities. Gravid females, which measured 246–298 cm TL, contained 16–22 embryos. Embryos, which were observed from October–July, measured between 11.1–54.6 cm TL and the available data agreed with a gestation period of 10–11 months that starts in September and ends in June/July. Size at birth was 47–55 cm TL. Sampling data indicated that most fishing activity occurred in nearshore and around seamounts in the central-eastern Pacific Ocean, with much of the landed catch comprising immature individuals. This study documents the reproductive biology of S. lewini in the central-eastern Pacific Ocean and provides additional information to improve management and conservation measures for this species.

scholarly journals Demographic Processes Underlying Subtle Patterns of Population Structure in the Scalloped Hammerhead Shark, Sphyrna lewini

PLoS ONE ◽  
2011 ◽  
Vol 6 (7) ◽  
pp. e21459 ◽  
Author(s):  
Holly A. Nance ◽  
Peter Klimley ◽  
Felipe Galván-Magaña ◽  
Jimmy Martínez-Ortíz ◽  
Peter B. Marko
Keyword(s):  
Population Structure ◽  
Sphyrna Lewini ◽  
Hammerhead Shark ◽  
Scalloped Hammerhead ◽  
Demographic Processes

scholarly journals Genetic connectivity and diversity of endangered species the scalloped hammerhead shark Sphyrna lewini (Griffith & Smith 1834) population in Indonesia and Western Indian Ocean

2020 ◽  
Author(s):  
Sutanto Hadi ◽  
Noviar Andayani ◽  
Effin Muttaqin ◽  
Benaya M Simeon ◽  
Muhammad Ichsan ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Indian Ocean ◽  
Endangered Species ◽  
Western Indian Ocean ◽  
Sphyrna Lewini ◽  
Hammerhead Shark ◽  
Scalloped Hammerhead ◽  
Indonesian Population ◽  
West Papua

AbstractThe scalloped hammerhead shark Sphyrna lewini is an endangered species which expected to population declined worldwide including in Indonesia due to overexploited. However, there is a lack of information regarding recent population structure to promote proper management and conservation status in Indonesia. This study aimed to investigate the genetic diversity, population structure and connectivity of S. lewini population in Indonesia from three major sharks landing sites in Aceh (n= 41), Balikpapan (n= 30), Lombok (n= 29), and additional sequences retrieved from West Papua (n= 14) and Western Indian Ocean population (n= 65). Analyses of mitochondrial CO1 gene successfully identified a total of 179 sequences of S. lewini with an average 594 bp nucleotide with 40 polymorphic loci in 4 haplotypes for Indonesian population and 8 haplotypes for Western Indian Ocean. The overall values of genetic diversity in Indonesia was high (Hd= 0.7171; π= 0.0126), with the highest was in Aceh (Hd= 0.6683; π= 0.0198), and the lowest was in Papua (Hd= 0.1429; π= 0.0005), while in Western Indian Ocean the overall value was fairly low (Hd= 0.2322; π= 0.0010). The AMOVA and FST revealed three significant population subdivisions in Indonesia (FST= 0.4415; p < 0.001) with separated population for Aceh and West Papua, and a mixing population between Balikpapan and Lombok (FST= 0.044; p = 0.089), whereas relatively no significant differentiation within population in Western Indian Ocean (FST= −0.0131; p = 0.6011), and significant different level showed by Indonesian population compared with Western Indian Ocean population (FST= 0.7403; p < 0.001). The construction of haplotype network exhibited evidence of gene flow and haplotype sharing between populations. This result indicated a complex and limited connectivity population of S. lewini in Indonesia, and between Western Indian Ocean in regional scale which need co-management action across region.

scholarly journals Population structure and reproductive biology of Metamysidopsis neritica (Crustacea: Mysidacea) in a sand beach in south Brazil

2008 ◽  
Vol 25 (3) ◽  
pp. 403-412 ◽  
Author(s):  
Patrícia Calil ◽  
Carlos A. Borzone
Keyword(s):  
Population Structure ◽  
Reproductive Biology ◽  
Direct Relationship ◽  
Surf Zone ◽  
Population Characteristics ◽  
Egg Volume ◽  
Sand Beach ◽  
The World ◽  
Egg Number ◽  
South Brazil

Mysidacea are common sublittoral crustaceans that inhabit all coasts in the world. In this study, the population characteristics and the reproductive biology of Metamysidopsis neritica Bond-Buckup & Tavares, 1992 were studied in the surf zone of a south Brazilian beach (Atami). Mysids were sampled at monthly intervals from August, 1999 to July, 2000 (total of 29,490 individuals). Individuals were classified into six population categories. The highest abundance occurred in May (8,665) and August (6,415), and lowest in September (336) and December (368). Three main generations were identified, namely the summer, fall and winter generations. The winter generation was the longest (four to five months). The fall generation lasted four months, and the summer one extended from three to four months. Ovigerous females occurred throughout the year, with a greater proportion in July. The number of eggs or larvae varied from one to 16. Weak associations were found between female length and egg number, egg volume, and the number of larvae with and without eyes. Egg volume increased during the coldest season, whereas the smallest values were recorded during summer. These results suggest a possible direct relationship between egg volume and generation longevity.

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