Set net is a fishing gear to set permanently in the fishing ground. Set net othosiami was developed by Center for Fisheries Development Department of Marine and Fisheries (BPPI) Semarang; it had been operated in 2010 at the Gulf Mallasoro, Jeneponto. The data information was collected regarding productivity, compositioning and catching diversity was taken from the catching data in 2011-2013. The study aims were to analyze catching trend, catching composition types and catching diversity. This study was conducted on January and February 2014 at the Gulf Mallasoro, Jeneponto. The method was used descriptive method. Based on the data from 2011-2013 on September-October showed a decline catching trend while the amount of cacthing trend consisted to 91 species. The pelagic fish has been identified for 31 species and 26 species belongs to demersal fish out of 57 species were found. The most dominant fish was Peperek (Leiognathus splendens) with 27% of catched fishes. The diversity index (H') catching fish period 2011-2013 ranged from 2.61-2.74 which regard to moderate category diversity. Furthermore, the value of evenness index (E) was more evenly 0.63-0.70 categorical. The dominance index value (D) showed within 0.12 to 0.15 there was no dominant species.

Indian mackerel (Rastellinger kanagurta) is one of the fish that can be caught by fishermen in North Gorontalo waters. Excessive fishing without regard to the condition of the fish will cause a decrease in the quality and quantity of fish resources. Estimation of size at first maturity is one way to determine population development in water. This study aims to determine the relationship between the level of gonad maturity and the fecundity of Indian mackerel in North Gorontalo waters. This research was conducted in October-December 2021 at the Kwandang Archipelago Fishing Port. The level of maturity of the gonads was observed morphologically and the determination of fecundity was observed using volumetric and gravimetric methods. The maturity level of Indian Mackerel fish in North Gorontalo waters is dominated at level 1. The highest fecundity is 14,800 eggs and the lowest is 5,000 eggs. The relationship between the level of gonad maturity and fecundity is directly proportional, if the gonadal maturity value is high, the fecundity value will also be higher. The spawning season for Indian mackerel in North Gorontalo waters does not take place in October-December, this is characterized by low fecundity. Based on the gonadal maturity values every month, the peak spawning of Indian mackerel (Rastellinger kanagurta) allegedly occurred shortly after the highest GSI values.

No abstract

Tujuan penelitian ini adalah untuk mengetahui karakteristik biologi ikan layang dan laju eksploitasi ikan Layang yang ada di perairan Gorontalo Utara. Pengambilan sampel ikan dilakukan dari bulan Mei-Agustus 2021 dengan mengukur panjang total dan pengamatan kematangan gonad yang dilakukan Pengamatan TKG akan dilakukan menggunakan mikroskop. Hasil penelitian menunjukkan bahwa sebaran panjang total berkisar antara 15,5 – 22,5 cm, nilai eksponen b < 3 sehingga memiliki pola pertumbuhan bersifat allometrik negatif yang berarti pertambahan berat lebih lambat dari pertambahan panjang. Nisbah kelamin ikan Layang jantan dan betina tidak berimbang yaitu 2,277 : 1. Ikan yang tertangkap didominasi tingkat kematangan gonad tingkat III - IV. Estimasi nilai parameter pertumbuhan dimana panjang asimtotik adalah 23,6 cm; Nilai koefisien pertumbuhan per tahun adalah 0,67 cm. Nilai panjang pertama kali matang gonad lebih kecil dibandingkan dengan ukuran panjang rata-rata tertangkap serta laju eksploitasi ikan layang yang didapatkan melebihi rasio eksploitasi seimbang diindikasikan dapat mengganggu stok ikan layang di perairan. A B S T R A C T The purpose of the study was to determine the biological characteristics and rate exploitation of scad in the waters of North Gorontalo. Fish sampling was carried out by measuring the total length and observing the maturity of the gonads from May – August 2021. The results showed that the total length distribution ranged from 15.5 – 22.5 cm, growth pattern of Decapterus russelli was negative allometric, which means the weight gain is slower than the length gain. The sex ratio of male and female fish was 2,277 : 1. The fish caught are dominated by the level of maturity level of the gonads III - IV. The estimated value of growth parameters where the asymptotic length is 23.6 cm; The value of the growth coefficient per year is 0.67 cm. The value of the length at first maturity of the gonads is smaller than the average length caught and the exploitation rate of scad that is obtained that exceeds the balanced exploitation ratio is indicated does not support the balance stock of scad in the waters.