scholarly journals SOME BIOLOGICAL ASPECTS OF SCALLOPED HAMMERHEAD SHARKS (Sphyrna lewini Griffith & Smith, 1834) CAUGHT FROM COASTAL FISHERIES IN THE EASTERN INDIAN OCEAN

2015 ◽  
Vol 21 (2) ◽  
pp. 91
Author(s):  
Umi Chodrijah ◽  
Bram Setyadji
Keyword(s):  
Indian Ocean ◽  
Size Composition ◽  
Biological Data ◽  
Biological Information ◽  
Eastern Indian Ocean ◽  
Coastal Fisheries ◽  
Hammerhead Shark ◽  
Total Length ◽  
Scalloped Hammerhead ◽  
The World

Indonesia has the largest chondrichthyan fishery in the world, with a reported of 105,000 and 118,000 tonnes landed in 2002 and 2003 respectively. Scalloped hammerhead shark was either targeted or by-catch from this fishery, mostly for its fins. Despite of the growing concern around the world, the availability of biological data of this species, especially in the Eastern Indian Ocean is still lacking. The objectives of this paper are to present some biological information (size composition and sex ratio) of the scalloped hammerhead, from coastal fisheries in Eastern Indian Ocean. The data used for the analysis comprised of two components, i.e. survey data in 2010 (February, March, June, August, October and December) and data from daily monitoring shark landing in 2013 (January to December). Substantially lower mean size, more immature sharks and more frequent of female caught over years showed that scalloped hammerhead shark in the Eastern Indian Ocean are facing intensive fishing pressure which could lead to overfishing. This could harm the sustainability of scalloped hammerhead shark resource in the long run. The relationship between clasper length and total length was positively correlated where every 5 cmTL increment on clasper length adding 51 cmTL on total length.

scholarly journals CARACTERIZACIÓN DE LA PESCA DEL TIBURÓN MARTILLO SPHYRNA LEWINI , EN LA PARTE EXTERNA DEL GOLFO DE NICOYA, COSTA RICA

2009 ◽  
Vol 1 ◽  
pp. 175 ◽  
Author(s):  
Ilena Zanella ◽  
Andrés López ◽  
Rándall Arauz
Keyword(s):  
Costa Rica ◽  
Outer Part ◽  
Shark Species ◽  
Central Pacific ◽  
Sphyrna Lewini ◽  
Hammerhead Shark ◽  
Total Length ◽  
Management Actions ◽  
Scalloped Hammerhead ◽  
Gulf Of Nicoya

En el ámbito nivel mundial, el tiburón martillo (Sphyrna lewini) es una de las especies más afectadas por la sobrepesca y el aleteo. Recientemente se incorporó a la Lista Roja de la UICN como especie en peligro de extinción. El presente estudio pretendió caracterizar la pesca y la distribución de S. lewini en la parte externa del Golfo de Nicoya. Para lograr este propósito, se realizaron muestreos entre marzo del 2006 y mayo del 2007 y se analizaron los tiburones martillo capturados por pescadores artesanales afiliados a la Cooperativa artesanales de Pescadores de Tárcoles (CoopeTárcoles R. L.), que faenan en la parte externa del Golfo de Nicoya. Para cada tiburón, se determinó la longitud total, la zona de pesca donde se capturó y el arte utilizado. En total se analizaron 273 tiburones. Se identificó un área de crianza primaria en el Peñón y se determinó que existe una relación lineal positiva entre la longitud total y la profundidad de la zona de pesca (R2 = 0.4296; p ‹ 0.0001), y la longitud total y la distancia de la zona de pesca de la desembocadura del río Grande de Tárcoles (R2 = 0.4052; p ‹ 0.0001). Los tiburones de menor tamaño (crías) se encontraron en la zona del Peñón, donde las aguas son poco profundas, turbias y productivas, ofreciendo a las crías alimento y protección de los depredadores. Por lo cual, se recomienda proteger esta zona, en particular en marzo, abril y mayo, época de nacimiento de las crías.The scalloped hammerhead shark (Sphyrna lewini) is one of the shark species most impacted by overfishing, and is currently listed by the IUCN Red List as an Endangered.  This research sought to characterize the distribution of S. lewini in the external area of Gulf of Nicoya, central Pacific coast of Costa Rica, based on observations from a coastal artisanal fishery. From March 2006 to May 2007, we analyzed scalloped hammerhead shark landings by members of the Tarcoles Artisanal Fishermen's Cooperative (CoopeTárcoles R. L.), who operate in the outer part of the Gulf of Nicoya. We measured the total length of each shark, recorded the reported location of capture, and the gear used. In total, we recorded data for 273 sharks landed. We determined that total length holds a positive linear relationship with the depth of the fishing area (R2 = 0.4296, *** p <.0001) as well as with the distance from the mouth of the Tárcoles River (R2 = 0.4052, *** p <.0001). The smaller sharks (pups) were caught in a fishing site known as Peñon, slightly north of the mouth of the Tarcoles River, where the waters are shallow, turbid and highly productive, providing food and shelter for the pups.  As pups mature and attain larger sizes, they move towards deeper waters away from the Tarcoles River, out of the Gulf of Nicoya. We identify Peñon as a primary nursery for scalloped hammerhead sharks, and recommend management actions that seek to reduce fishing effort between March and May, when pups are born.

scholarly journals Spatial Variation in Primary Production in the Eastern Indian Ocean

2021 ◽  
Vol 8 ◽  
Author(s):  
Haijiao Liu ◽  
Yuyao Song ◽  
Xiaodong Zhang ◽  
Guicheng Zhang ◽  
Chao Wu ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Primary Production ◽  
Carbon Fixation ◽  
Monsoon Season ◽  
Biological Data ◽  
Eastern Indian Ocean ◽  
Light Limitation ◽  
Photic Zone ◽  
Production Rates ◽  
Study Region

To examine the spatial pattern and controlling factors of the primary productivity (PP) of phytoplankton in the eastern Indian Ocean (EIO), deck-incubation carbon fixation (a 14C tracer technique) and the related hydrographic properties were measured at 15 locations during the pre-summer monsoon season (February–April 2017). There are knowledge gaps in the field observations of PP in the EIO. The estimated daily carbon production rates integrated over the photic zone ranged from 113 to 817 mgC m–2 d–1, with a mean of 522 mgC m–2 d–1. The mixed-layer integrated primary production (MLD-PP) ranged from 29.0 to 303.7 mgC m–2 d–1 (mean: 177.2 mgC m–2 d–1). The contribution of MLD-PP to the photic zone-integrated PP (PZI-PP) varied between 19 and 51% (mean: 36%). Strong spatial variability in the carbon fixation rates was found in the study region. Specifically, the surface primary production rates were relatively higher in the Bay of Bengal domain affected by riverine flux and lower in the equatorial domain owing to the presence of intermonsoonal Wyrtki jets, which were characterized by a depression of thermocline and nitracline. The PZI-PP exhibited a linear (positive) relationship with nutrient values, but with no significance, indicating a partial control of macronutrients and a light limitation of carbon fixation. As evident from the vertical profiles, the primary production process mainly occurred above the nitracline depth and at high photosynthetic efficiency. Phytoplankton (&gt;5 μm), including dinoflagellates, Trichodesmium, coccolithophores, and dissolved nutrients, are thought to have been correlated with primary production during the study period. The measured on-deck biological data of our study allow for a general understanding of the trends in PP in the survey area of the EIO and can be incorporated into global primary production models.

scholarly journals Genetic connectivity of the scalloped hammerhead shark Sphyrna lewini across Indonesia and the Western Indian Ocean

PLoS ONE ◽  
2020 ◽  
Vol 15 (10) ◽  
pp. e0230763
Author(s):  
Sutanto Hadi ◽  
Noviar Andayani ◽  
Efin Muttaqin ◽  
Benaya M. Simeon ◽  
Muhammad Ichsan ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Western Indian Ocean ◽  
Genetic Connectivity ◽  
Sphyrna Lewini ◽  
Hammerhead Shark ◽  
Scalloped Hammerhead

scholarly journals The conservation of Madagascar’s orchids . A model for an integrated conservation project

Lankesteriana ◽  
2015 ◽  
Vol 7 (1-2) ◽  
Author(s):  
Phillip Cribb ◽  
Johan Hermans
Keyword(s):  
Indian Ocean ◽  
East Africa ◽  
Eastern Indian Ocean ◽  
Conservation Project ◽  
Large Island ◽  
The World ◽  
Integrated Conservation

The fauna and flora of the large island of Madagascar, situated in the eastern Indian Ocean off the coast of East Africa, has been recognised for many years as one of the most peculiar anywhere in the world, and as one of the most endangered. It has a rich orchid flora of about 1000 species.  

scholarly journals First record of scalloped hammerhead shark Sphyrna lewini (Carcharhiniformes: Sphyrnidae) in freshwater habitat

2020 ◽  
Vol 30 ◽  
pp. 113-118
Author(s):  
Muhammad Iqbal ◽  
Doni Setiawan ◽  
Arum Setiawan ◽  
Indra Yustian
Keyword(s):  
First Record ◽  
Unexpected Finding ◽  
Sphyrna Lewini ◽  
Freshwater Habitat ◽  
Hammerhead Shark ◽  
Total Length ◽  
Scalloped Hammerhead ◽  
East Kalimantan

A scalloped hammerhead shark Spyraena lewini (Griffith & Smith, 1834)  with c. 40 cm of total length was stranded and photographed on 6 April 2020 in Mahakam river, East Kalimantan province, Indonesia. This unexpected finding is represent a first ever know inland record of S. lewini in freshwater habitat.

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 Impact of the Strong Downwelling (Upwelling) on Small Pelagic Fish Production during the 2016 (2019) Negative (Positive) Indian Ocean Dipole Events in the Eastern Indian Ocean off Java

Climate ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 29
Author(s):  
Jonson Lumban-Gaol ◽  
Eko Siswanto ◽  
Kedarnath Mahapatra ◽  
Nyoman Metta Nyanakumara Natih ◽  
I Wayan Nurjaya ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Indian Ocean Dipole ◽  
Pelagic Fish ◽  
Eastern Indian Ocean ◽  
Fish Production ◽  
Small Pelagic Fish ◽  
Field Surveys ◽  
Chl A ◽  
Positive Indian Ocean Dipole ◽  
The Impact

Although researchers have investigated the impact of Indian Ocean Dipole (IOD) phases on human lives, only a few have examined such impacts on fisheries. In this study, we analyzed the influence of negative (positive) IOD phases on chlorophyll a (Chl-a) concentrations as an indicator of phytoplankton biomass and small pelagic fish production in the eastern Indian Ocean (EIO) off Java. We also conducted field surveys in the EIO off Palabuhanratu Bay at the peak (October) and the end (December) of the 2019 positive IOD phase. Our findings show that the Chl-a concentration had a strong and robust association with the 2016 (2019) negative (positive) IOD phases. The negative (positive) anomalous Chl-a concentration in the EIO off Java associated with the negative (positive) IOD phase induced strong downwelling (upwelling), leading to the preponderant decrease (increase) in small pelagic fish production in the EIO off Java.

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