Why do fish reach first maturity when they do?

2021 ◽  
Author(s):  
Daniel Pauly
Keyword(s):  
First Maturity

Correlation Studies of Some Agronomic Characters in Sesame

1970 ◽  
Vol 6 (1) ◽  
pp. 27-31 ◽  
Author(s):  
M. Osman Khidir ◽  
H. El Gizouli Osman
Keyword(s):  
Seed Size ◽  
Seed Coat ◽  
Coat Colour ◽  
Stem Height ◽  
Agronomic Characters ◽  
Seed Coat Colour ◽  
Correlation Studies ◽  
First Maturity ◽  
Criteria For Selection ◽  
Number Of Branches

SummaryIn 90 local sesame types there was some association between seed coat colour and seed size, stem height, number of branches, number of pods, yield per plant and earliness. Forty-five coefficients show the degree of correlation between ten agronomic characters. Yield was significantly and positively correlated with all characters except the number of days to first flowering and to first maturity. Stem height, number of pods per plant and seed size seem to be the best criteria for selection in sesame.

Biology of four species of Whiting (Pisces: Sillaginidae) in Botany Bay, NSW

1988 ◽  
Vol 39 (6) ◽  
pp. 709 ◽  
Author(s):  
JJ Burchmore ◽  
DA Pollard ◽  
MJ Middleton ◽  
JD Bell ◽  
BC Pease
Keyword(s):  
New South ◽  
Abundant Species ◽  
Male And Female ◽  
Fish Size ◽  
South Wales ◽  
Gonadal Maturity ◽  
Habitat Differences ◽  
Temporal And Spatial ◽  
First Maturity ◽  
Spatial Habitat

Four species of whiting (Family Sillaginidae) were collected from Botany Bay, New South Wales, between 1977 and 1979: Sillago ciliata (sand whiting), S. maculata maculata (trumpeter whiting), S. robusta (stout whiting) and S. bassensis flindersi (eastern school whiting). Sillago ciliata was the most abundant species over-all. Sillago ciliata was caught in greatest numbers in Zostera seagrass and shallow sandy habitats, whereas S. m. maculata, S. robusta and S. b. flindersi were most abundant over deeper muddy and sandy habitats. Sillago ciliata and S. b. flindersi were present mainly as juveniles. Gonosomatic indices and gonadal maturity stages of S. ciliata and S. m. maculata peaked around February. These species probably spawn within the Bay. Length to caudal fork at first maturity was 24 cm for male and female S. ciliata, 19 cm for male and female S. m. maculata, 17 cm for male and 18 cm for female S. robusta, and 14 cm for male and female S. b. flindersi. Although all species fed mainly on polychaetes and crustaceans, there was little overlap in specific dietary items between species. Variations observed in diet were due to fish size and temporal and spatial habitat differences within and among species.

Aspects of the fishery, maturation and net selectivity of the wedge sole (Dicologoglossa cuneata) off south-western Iberia: implications for fishery management

2009 ◽  
Vol 90 (7) ◽  
pp. 1465-1474 ◽  
Author(s):  
Miguel Neves Santos ◽  
Pedro Gil Lino
Keyword(s):  
Fishery Management ◽  
River Mouth ◽  
Mesh Size ◽  
Scientific Basis ◽  
Catch Per Unit Effort ◽  
Important Species ◽  
Gill Net ◽  
Catch Rates ◽  
Log Normal ◽  
First Maturity

The wedge sole (Dicologoglossa cuneata, Moreau 1881) is a commercially important species for the artisanal fleet operating off the south-western Iberian Peninsula. During 2004 and 2005 a study was undertaken aiming to provide a scientific basis for management. Data collection included information on aspects of the fishery, spawning season, size at first maturity, tangle and gill-net selectivity. Seven nominal mesh sizes were used (40, 45 and 50 mm tangle nets and 40, 50, 60 and 70 mm gill-nets). Spawning lasts from December to June, with peaks in March and May. Length at first maturity for females was estimated at 18.5 cm. Catch rates decreased sharply with increasing mesh size, with tangle nets providing the highest yields. The log-normal selectivity model provided the best fit for specimens that were wedged. The higher catch-per-unit-effort of the smaller mesh sizes and the modal length of the fitted selectivity curve being below the size-at-maturity for wedge sole, suggests that the 50 mm nominal mesh size tangle net is the most appropriate for ensuring the fishery sustainability. Nevertheless, the minimum legal size should increase to at least 18 cm and a time–area closure should be implemented off the Guadiana River mouth.

scholarly journals Reproductive biology of Haemulon plumieri (Teleostei: Haemulidae) in Ceará state, Northeastern Brazil

2013 ◽  
Vol 73 (2) ◽  
pp. 391-396 ◽  
Author(s):  
RA Shinozaki-Mendes ◽  
J Santander-Neto ◽  
JRF Silva ◽  
FHV Hazin
Keyword(s):  
Reproductive Biology ◽  
Fishing Effort ◽  
Northeastern Brazil ◽  
Tropical Species ◽  
Stock Management ◽  
Western Atlantic ◽  
Total Fecundity ◽  
Maturation Stages ◽  
First Maturity ◽  
Management And Conservation

The Haemulon plumieri is a typical reef-associated and tropical species found in warm and temperate waters of the Western Atlantic. Due to the large fishing effort directed to H. plumieri, the knowledge about its reproductive biology is essential for correct stock management and conservation. The aim of this study was to characterise reproductive biology with a focus on its seasonal variation of gonadal maturation stages, first maturation size and fecundity. Specimens were monthly collected and a total of 119 females and 136 males were analysed. The reproductive cycle of Haemulon plumieri is seasonal, with higher activity between March and May. Size at first maturity (L50) was estimated at 16.86 and 18.55 cm for females and males, respectively. The total fecundity ranged between 17,816 and 120,333 mature oocytes per female and relative fecundity was 235 ± 63 oocyte.g−1 whereas batch fecundity varied between 20 and 25% from total fecundity. Since the species is widely caught, we suggest a closed season from March to May and to establish a minimum catch size of 18.5 cm for both sexes, since there is no evident sexual dimorphism.

scholarly journals Polyphasic growth in fish: a case study with Corydoras paleatus (Siluriformes, Callichthyidae)

2016 ◽  
Vol 106 (0) ◽  
Author(s):  
José R. S. Barradas ◽  
Isabel S. Lermen ◽  
Gabriel G. Larré ◽  
Thaís P. Martins ◽  
Nelson F. Fontoura
Keyword(s):  
Growth Pattern ◽  
Rio Grande ◽  
Allometric Growth ◽  
Rio Grande Do Sul ◽  
Power Equation ◽  
Length Relationship ◽  
First Maturity ◽  
Changing Rate ◽  
Specific Length

ABSTRACT A weight-length relationship was established for Corydoras paleatus (Jenyns, 1842) (Siluriformes, Callichthyidae) (n=596) from samples taken in November-December 2009 and March-April 2010, in Pinguela Lagoon (29°46'57"S; 50°11'16"W), Rio Grande do Sul, Brazil. The species showed a polyphasic allometric growth pattern, each stanza described by an independent power equation controlled by a switch function: W = a1Lb1 ∙ (1 + eRsc ∙ (L-SCP))-1 + a2Lb2 ∙ [1 - (1 + eRsc ∙ (L-SCP))-1] ; where W is the expected weight for a specific length L, a1 and a2 are the proportionality coefficients for stanzas 1 and 2, b1 and b2 are the allometric coefficients for stanzas 1 and 2, Rsc is the stanza changing rate for the switch function and SCP is the stanza changing point for the switch function. The stanza changing point was estimated as 5.28 cm, corresponding with the length at first maturity for this species Lmat (5.29 cm). Our data suggest that a complex growth pattern can be in nature, and perhaps not often identified because trends are obscured by natural variability.

scholarly journals STATUS PERIKANAN HUHATE (POLE AND LINE) DI BITUNG, SULAWESI UTARA

2017 ◽  
Vol 14 (3) ◽  
pp. 313 ◽  
Author(s):  
Budi Nugraha ◽  
Enjah Rahmat
Keyword(s):  
Yellowfin Tuna ◽  
Fishing Ground ◽  
Thunnus Albacares ◽  
Skipjack Tuna ◽  
Katsuwonus Pelamis ◽  
Coryphaena Hippurus ◽  
North Sulawesi ◽  
The Status ◽  
Catch Composition ◽  
First Maturity

Tulisan ini menyajikan tentang status perikanan huhate di Bitung meliputi deskripsi unit penangkapan, daerah penangkapan, komposisi hasil tangkapan, catch per unit of effort, dan ukuran ikan pertama kali tertangkap. Data dikumpulkan selama tahun 2004 sampai dengan 2005. Hasil penelitian menunjukkan bahwa huhate yang terdapat di Bitung dioperasikan dengan kapal penangkapan yang terbuat dari kayu berukuran 50 sampai dengan 80 GT. Daerah penangkapan di sekitar lokasi rumpon di Laut Sulawesi dan Laut Maluku. Hasil tangkapan yang diperoleh terdiri atas cakalang (Katsuwonus pelamis), madidihang (Thunnus albacares), baby tuna (Thunnus spp.), dan tongkol (Auxis spp.) serta hasil tangkapan sampingan yaitu lemadang (Coryphaena hippurus) dan sunglir (Elagatis bipinnulatus). Hasil analisis catch per unit of effort diperoleh bahwa nilai catch per unit of effort baby tuna (Thunnus spp.) mengalami kenaikan pada bulan Agustus 2004, dan cakalang (Katsuwonus pelamis) mengalami kenaikan pada bulan September 2004. Hasil analisis terhadap ukuran pertama kali cakalang (Katsuwonus pelamis) tertangkap oleh huhate 49,3 FLcm. Ukuran ini lebih panjang dibandingkan ukuran pertama kali cakalang (Katsuwonus pelamis) matang gonad. Sedangkan hasil analisis terhadap ukuran pertama kali madidihang (Thunnus albacares) tertangkap oleh huhate 51,6 FLcm. Ukuran ini lebih pendek dibandingkan ukuran pertama kali madidihang (Thunnus albacares) matang gonad. This paper presents the status of pole and line fishery in Bitung of North Sulawesi, consisting of description of fishing gear, fishing ground, catch composition, catch per unit of effort, and length at first capture. Data were collected during the period of 2004 until 2005. Results show that the pole and line in Bitung operated by wooden vessels of 50 until 80 GT. The fishing grounds were the waters around FADs location in Sulawesi Sea and Maluku Sea. Catch composition consists of skipjack tuna (Katsuwonus pelamis), yellow fin tuna (Thunnus albacares), baby tuna (Thunnus spp.), and frigate tuna (Auxis spp.), while the bycatch consisted of dolphinfish (Coryphaena hippurus) and rainbow runner (Elagatis bipinnulatus). Catch per unit of effort analysis shows that catch per unit of effort value of baby tuna (Thunnus spp.) increased on August 2004, whereas catch per unit of effort value of skipjack tuna (Katsuwonus pelamis) increased on September 2004. The length at first capture of skipjack tuna (Katsuwonus pelamis) was 49,3 FLcm. The catch size was bigger than the length at first maturity for skipjack tuna (Katsuwonus pelamis). The length at first capture of yellowfin tuna (Thunnus albacares) was 51,6 FLcm. This catch size was smaller than the length at first maturity for yellowfin tuna (Thunnus albacares).

scholarly journals ASPEKBIOLOGI IKANKURISI (Nemipterus japonicus) DI PERAIRANTELUKBANTEN

2016 ◽  
Vol 8 (1) ◽  
pp. 21
Author(s):  
Selvi Oktaviyani ◽  
Mennofatria Boer ◽  
Yonvitner Yonvitner
Keyword(s):  
Fisheries Management ◽  
Average Length ◽  
Maturity Stage ◽  
Allometric Growth ◽  
Fishing Activity ◽  
Fish Resources ◽  
Nemipterus Japonicus ◽  
Males And Females ◽  
Biological Aspects ◽  
First Maturity

<p>Ikan kurisi (<em>Nemipterus japonicus</em>) merupakan salah satu sumber daya ikan ekonomis penting di Perairan Teluk Banten dan banyak didaratkan di Pelabuhan Perikanan Nusantara (PPN) Karangantu, Banten. Intensitas penangkapan yang tinggi akan menyebabkan tangkap lebih (<em>overfishing</em>), sehingga mengancam kelestarian ikan kurisi. Penelitian ini bertujuan untuk mengetahui beberapa aspek biologi ikan kurisi di Perairan Teluk Banten, seperti struktur ukuran panjang, rasio kelamin, hubungan panjang berat, tingkat kematangan gonad, ukuran panjang rata-rata tertangkap (Lc) dan ukuran pertama kali matang gonad (Lm). Informasi yang diperoleh dapat menjadi bahan pertimbangan dalam kegiatan pengelolaan perikanan. Lokasi pengambilan contoh dilakukan di Pelabuhan Perikanan Nusantara (PPN) Karangantu, Banten dari bulan Mei hingga Agustus 2012. Hasil penelitian menunjukkan bahwa ukuran panjang total ikan kurisi<em> </em>berkisar antara 98 dan 211 mm. Perbandingan kelamin jantan dan betina dalam keadaan seimbang dan memiliki pola pertumbuhan allometrik negatif yang menunjukkan pertumbuhan panjang lebih cepat dibandingkan pertumbuhan beratnya. Lebih dari 50% ikan-ikan yang diamati baik jantan maupun betina selama bulan pengamatan belum matang gonad (<em>immature</em>).  Ukuran pertama kali matang gonad adalah 196 mm sedangkan ukuran panjang rata-rata tertangkap adalah 146 mm. Banyaknya ikan yang tertangkap dalam ukuran kecil (kurang dari panjang pertama kali matang gonad) akan mengganggu kelestarian ikan kurisi.</p><p><em><br /></em></p><p><em>Japanese threadfin bream </em>(Nemipterus japonicus<span style="text-decoration: underline;">)</span><em> is one of the most important economical fish resources in the Gulf of Banten and many landed at Archipelago Fishing Port (PPN) of Karangantu. High intensity of fishing activity can cause an overfihing, and threat sustainability of japanese threadfin bream. The research was aimed to determine some biological aspects of japanese threadfin bream in the Gulf of Banten, such as structure of the length, sex ratio, length-weight relationship, gonad maturity stage, the average length of captured (Lc) and the length of first maturity (Lm). It is believed that the collected information can be taken into consideration in the fisheries management activities. The sample was collected at PPN Karangantu, Banten from May to August 2012. The result showed that the length of </em><em>this fish </em><em>ranged between 98 and 211 mm. Ratio of male and female is balance and have negative allometric growth pattern show that the length of growth is more faster than the weight of growth. More than 50% of fish sample both males and females were immature gonads. During observation, length of  first maturity was 196 mm and the average length of captured was 146 mm. </em><em>Many fishes caught was smaller than Lm, It will interfere the sustainability of japanese threadfin bream.</em></p>

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