scholarly journals Reproductive Biology of Ovigerous Female Emerita emeritus (Crustacea, Decapoda) in Bengkulu Coastal Waters, Indonesia: Egg Production and Reproductive Output

2016 ◽  
Vol 74 (3) ◽  
pp. 103-109 ◽  
Author(s):  
Ouratul Edritanti ◽  
Achmad Farajallah ◽  
Yusli Wardiatno

Abstract Emerita emeritus is an abundant species in Bengkulu coastal waters, but the knowledge of its reproductive biology is poor. The present study was conducted to elucidate the reproductive aspects of ovigerous female E. emeritus, including fecundity, egg volume and reproductive output. This study was conducted between January 2015 and January 2016 in Bengkulu coastal waters, Indonesia. Samples were collected manually using shovels and hands. The results showed that ovigerous females occurred every month. Fecundity increased significantly in ovigerous females proportional to the size. No correlation was shown between sea surface temperature and egg production. Fecundity and reproductive output decreased throughout the embryonic development.

2018 ◽  
Vol 11 (1) ◽  
pp. 5 ◽  
Author(s):  
R. Susanto ◽  
Jiayi Pan ◽  
Adam Devlin

Tidal mixing in the coastal waters of Hong Kong was investigated using a combination of in situ observations and high-resolution satellite-derived sea surface temperature (SST) data. An indicator of tide-induced mixing is a fortnightly (spring-neap cycle) signature in SST due to nonlinear interactions between the two principal diurnal and the two principal semi-diurnal tides. Both semi-diurnal and diurnal tides have strong tidal amplitudes and currents near Hong Kong. As a result, both the near-fortnightly (Mf) and fortnightly (MSf) tides are enhanced due to nonlinear tidal signal interactions. In addition, these fortnightly tidal signals are modulated by seasonal variability, with the maximum seasonal modulation of fortnightly tides occurring during the monsoon transition periods in May and October. The largest fortnightly signals are found in the southwestern part of the Pearl River estuary. Tidal constituent properties vary by space and depth, and high-resolution SST plays a pivotal role in resolving the spatial characteristics of tidal mixing.


2015 ◽  
Vol 63 (3) ◽  
pp. 207-216 ◽  
Author(s):  
Uwe Zimmermann ◽  
Fabrício Lopes Carvalho ◽  
Fernando L. Mantelatto

AbstractDecapod species have evolved with a variety of reproductive strategies. In this study reproductive features of the palaemonid shrimp Leander paulensiswere investigated. Individuals were collected in the coastal region of Ubatuba, São Paulo, Brazil. In all, 46 ovigerous females were examined in terms of the following reproductive traits: fecundity, reproductive output, brood loss and egg volume. Leander paulensis produces a large number of small eggs with an average fecundity of 635 ± 246 eggs. Egg volume increased significantly from early (0.034 ± 0.008 mm3) to late development stage (0.05 ± 0.012 mm3). The reproductive output did not correlate with female size. The weight of females bearing stage 2 eggs was significantly higher than that of females carrying stage 1 eggs. We assume that the reason for this weight gain is the recovery of female reserves that have been depleted for egg production. Moreover, we emphasize that this weight gain must be considered when evaluating weight-dependent variables such as reproductive output or brood loss in relation to female weight. Otherwise, an overestimation of these variables might lead to inaccurate results.


2018 ◽  
Vol 23 (4) ◽  
pp. 275 ◽  
Author(s):  
Komang Iwan Suniada ◽  
Eko Susilo

Perikanan pelagis di perairan Selat Bali telah diusahakan sejak lama. Data runtut tahun hasil tangkapan yang didaratkan cenderung berfluktuasi. Kajian ini bertujuan untuk mengetahui kondisi spasial dan temporal karakteristik oseanografi, terkait dengan dengan dinamika perikanan pelagis di Selat Bali. Data parameter oseanografi meliputi suhu permukaan laut (SPL) dan klorofill-a (chl-a) yang diperoleh dari citra satelit penginderaan jauh Aqua/Terra MODIS, sedangkan data sumberdaya perikanan pelagis berupa hasil tangkapan/satuan upaya (Catch per Unit Effort, CPUE) ikan pelagis diperoleh dari Tempat Pendaratan Ikan (TPI) Pengambengan, Jembrana - Bali pada periode Januari 2007 hingga Desember 2015. Uji statistik regresi linear berganda digunakan untuk mengetahui pengaruh parameter oseanografi terhadap kondisi perubahan sumberdaya perikanan pelagis. Sebaran spasial SPL menunjukkan bahwa pada Mei hingga November suhu permukaan laut cenderung rendah serta tidak ada perbedaan yang signifikan antara suhu di perairan pantai dan di laut lepas. Secara temporal terlihat bahwa suhu terendah terjadi pada musim timur yaitu pada Agustus 2007. Sebaran spasial chl-a menunjukkan bahwa peningkatan konsentrasi chl-a dimulai dari Mei hingga Oktober serta terdapat perbedaan yang signifikan antara chl-a perairan pantai dan laut lepas. Secara temporal terlihat bahwa konsentrasi chl-a tertinggi terjadi pada Oktober 2015. Faktor iklim yang merupakan faktor eksternal memberikan pengaruh terhadap perubahan konsentrasi chl-a pada lokasi penelitian. Faktor iklim tersebut adalah kecepatan angin dan kejadian El-Nino. Hasil analisis statistik menunjukkan bahwa perubahan parameter SPL dan chl-a secara bersama-sama berpengaruh signifikan terhadap perubahan CPUE ikan pelagis, namun secara parsial parameter chl-a memberikan pengaruh yang lebih signifikan dibandingkan dengan parameter SPL.Pelagic fisheries around Bali Strait have been exploited since decades. Based on monthly and annual landing data, fish production around Bali strait are very fluctuated. This study aims to determine the spatial and temporal conditions of oceanographic characteristics and how they relate to the dynamics of pelagic fisheries in the Bali Strait. The oceanographic parameter data consist of sea surface temperature (SST) and chlorophyll-a (chl-a) that obtained from Aqua / Terra MODIS remote sensing satellite imagery, while the dynamics of pelagic fish resource data indicated by Catch per Unit Effort (CPUE) derrived from landing place (TPI) Pengambengan, Jembrana - Bali in the period January 2007 to December 2015. Multiple linear regression analysis were applied to determine the effect of oceanographic parameters on the changing conditions of pelagic fishery resources. Spatial distribution of SPL indicates that in May to November sea surface temperature tends to be low and there is no significant difference between the temperature in coastal waters and on high seas. The temporal distribution shows that the lowest temperature occurred during the southeast monsoon in August 2007. The spatial distribution of chl-a showed that the chl-a concentration starts to increase from May to October and there were significant differences between chl-a coastal waters and high seas. The temporal distribution shows that the highest chl-a concentration occurred in October 2015. Climate factor which is an external factor has an effect on the change of chl-a concentration at the research location. Climatic factors are wind speed and El-Nino events. The result of the statistical analysis shows that the change of SPL and chl-a parameters together significantly influence on the CPUE of pelagic fish, but partially chl-a parameter gives highly significant effect than SST parameter.


Author(s):  
Hasan Sitorus ◽  
Zulham Apandy Harahap ◽  
Tifani Zianida

The east coast of North Sumatra is part of the Malacca Strait, a highly utilized fishing area. One of the commodities that can be harvested is the Yellowstripe Scad (Selaroides leptolepis). Through oceanography parameters, specifically temperature and chlorophyll-aconcentrations, it is possible to determine optimal fishing grounds which can be used as guidelines. One of the satellites that can detect sea surface temperature (SST) and chlorophyll-a concentrations is Aqua (EOS PM),which is equipped with a Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Data on the Yellowstripe Scad (Selaroide sleptolepis) were obtained from the Belawan Ocean Fishing Port (OFP). Based on the analysis of MODIS images from the Aqua satellite, the sea surface temperature of theeast coastal waters of North Sumatra in 2012 - 2016 ranged from 29oC – 32oC with chlorophyll-a concentrations ranging from 0.19 - 5.26 mg/m³. The largest harvest occurred during the west monsoon with a value of 143.46 tons and the lowest was during the east monsoon with a value of 139.87 tons. Yellowstripe Scad harvest has a negative correlation with the sea surface temperature with a correlation value of -0.365. Chlorophyll-a concentrations and harvest amount have a positive correlation value of 0.660. Yellowstripe Scad is predicted to yield the largest harvest during the west monsoon (December-February) between the Asahan and Labuhanbatu Regencies at coordinates 2.68oN - 2.74oN and 100.37oE - 100.44oE.


2019 ◽  
Vol 99 (06) ◽  
pp. 1435-1441 ◽  
Author(s):  
Kouassi Yves Narcisse Kouamé ◽  
Kouadio Justin Konan ◽  
Nahoua Issa Ouattara ◽  
Tidiani Koné

AbstractThe blue shark Prionace glauca is the most abundant species in the artisanal driftnet fishery off the coastal waters of Ivory Coast. The reproductive parameters were investigated with the aim of providing basic information on the reproductive biology for fisheries management. A total of 424 specimens (256 males and 168 females) ranging from 170–330 cm in total length (TL) were sampled between August 2014 and November 2016. Sample for embryonic sex ratio was obtained from 18 litters of 503 individuals (255 males and 248 females). The embryonic sex ratio was not significantly different from 1:1 (χ2 = 0.10, P > 0.05, N = 503). The size at 50% maturity (L50) was 218.1 cm TL for males and 223.3 cm TL for females. The litter size based on the number of embryos varied from 6 to 62, with an average of 30 embryos. Mating started in July whereas ovulation, fertilization and uterine eggs occurred in late October–November. Smallest embryos of 3–5 cm in stretch total length (STL) appeared in uterus from November to January. The embryo size varied widely among months, and well-pigmented embryos were already present in April–May samples, although most of them occurred in August–September, suggesting a gestation period of around 11 months. The absence of neonates in catches, as well as parturition females, does not support a hypothesis that parturition takes place in the Gulf of Guinea.


Sign in / Sign up

Export Citation Format

Share Document