Morfometric study of Seagrass Thalassia hemprichii, in Pasir Panjang Beach, Paputungan Village, West Likupang, Minahasa Utara

This study was aimed at knowing seagrass species in the study site and comparing the morphometry of seagrass Thalassia hemprichii with sampling station. Sample collection employed haphazard survey, and samples and substrate were taken using a big knife, washed in seawater, an in seawater, and put into a seawater-containing bucket. Sampling points were determined by GPS, and 30 individuals of T. hemprichii were taken. Results showed that T. hemprichii in Pasir Panjang coastal waters has bigger size in mangrove and seagrass areas than that in the coral reefs. It could result from that mangrove and seagrass areas grew in muddy substrate that contained higher nutrients and calmer water condition than those in coral reefs with coral debris substrate.Keywords : Morfometrics, Thalassia hemprichii, Pasir Panjang BeachABSTRAKTujuan penelitian adalah untuk mengetahui jenis lamun apa saja yang ada di lokasi penelitian ini dan membandingkan ukuran morfometrik lamun Thalassia hemprichii berdasarkan stasiun pengambilan sampel. Pengambilan data dilakukan dengan mengunakan metode survei jelajah, sampel diambil dengan parang bersamaan dengan substrat, dicuci dengan air laut dan dimasukan kedalam ember yang berisi air laut. Saat pengambilan sampel dilakukan, posisi diplot dengan mengunakan GPS dan dilanjutkan dengan pengambilan sample lamun Thalassia hemprichii sebanyak 30 individu setiap stasiun, Pada hasil yang diperoleh terlihat bahwa spesies Thalassia hemprichii di Perairan Pantai Pasir Panjang yang lebih besar di daerah mangrove dan daerah lamun dan yang lebih kecil adalah daerah terumbu karang.  Hal ini disebabkan, karena daerah mangrove dan lamun tersebut tumbuh pada subsrat lumpur yang memiliki kandungan nutrien lebih tinggi dibandingkan dengan daerah terumbu karang dengan subsrat pecahan karang, dan keadaan perairan pada subsrat lumpur lebih tenang sehingga banyak mengendapkan sedimen.Kata Kunci : Morfometrik. Thalassia hemprichii. Pantai Pasir Panjan

Types and Size Distribution of Parrotfish (Family Scaridae) Caught with Gillnets in the Waters off Taduna Village, Kabaruan Island.

The objective of this research is to identify the types and size distribution of parrotfish in the waters of Taduna Village. The research was conducted using sampling methods. Samples were collected over a period of two months from the catches landed in Taduna Village by local fishermen. The fishermen used gillnets for their catches. The length of each fish was measured from the tip of the mouth to the end of the tail using a millimeter-scale ruler with a precision of 0.1 cm. The weight of the fish was measured using a digital scale with a resolution of one gram. The length of each species was analyzed using frequency distribution and presented in length and weight histograms. Based on the data obtained from the measurements of Family Scaridae fish, a total of 53 individuals were collected, consisting of 8 species: Chorurus bleekeri (11 individuals), Calotomus carolinus (4 individuals), Chorurus japanensis (6 individuals), Chlorurus microrhinos (2 individuals), Scarus frenatus (16 individuals), Scarus russell (4 individuals), Scarus spinus (5 individuals), and Scarus tricolor (5 individuals). The distribution of Family Scaridae fish in the waters off Taduna Village shows varying lengths and weights for each species. For example, Chorurus bleekeri ranged from 18.9 to 26.5 cm in length and weighed between 150 and 394 grams, Chorurus japanensis had a length distribution between 17.5 and 27.4 cm and weighed from 119 to 465 grams, and Scarus frenatus ranged from 18.3 to 24.5 cm in length and weighed between 117 and 308 grams." Keywords: Parrotfish, Scaridae, Types, Size, Kabaruan. Abstrak Tujuan penelitian ini yaitu untuk mengetahui jenis dan distribusi ukuran ikan kakatua di perairan Desa Taduna. Penelitian ini menggunakan metode sampling. Pengambilan sampel dilakukan dalam waktu dua bulan dari hasil tangkapan nelayan yang didaratkan di Desa Taduna. Alat yang digunakan nelayan adalah jaring insang mono filamen.  Seluruh panjang ikan diukur dari ujung mulut hingga ujung ekor dengan penggaris skala milimeter dengan ketelitian 0,1 cm. Berat ikan diukur dengan timbangan digital dengan resolusi satu gram. Panjang setiap spesies dianalisis menggunakan distribusi frekuensi dan ditampilkan dalam histogram panjang dan berat. Berdasarkan data hasil pengukuran ikan Famili Scaridae diperoleh sebanyak 53 individu yang terdiri dari 8 spesies yaitu Chorurus bleekeri (11 individu), Calotomus carolinus (4 individu), Chorurus japanensis (6 individu), Chlorurus microrhinos (2 individu), Scarus frenatus (16 individu), Scarus russellii (4 individu), Scarus spinus (5 individu) dan Scarus tricolor (5 individu). Distribusi ikan Famili Scaridae di perairan depan Desa Taduna memiliki ukuran panjang  dan berat yang bervariasi yaitu spesies Chorurus bleekeri berkisar 18,9-26,5 cm dan berat 150-394 gram, Chorurus japanensis memiliki distribusi ukuran panjang berkisar 17,5-27,4 cm dan berat 119-465 gram dan Scarus frenatus memiliki distribusi ukuran panjang berkisar 18,3-24,5 cm dan berat 117-308 gram. Kata kunci : Ikan kakatua, Scaridae, Jenis, Ukuran, Kabarua

Gastropod community structure on seagrass beds in Bahoi Village, North Minahasa

The village of Bahoi has a vast expanse of seagrass meadows of approximately 16.50 Ha, located between mangrove and coral reef ecosystems. This study aims to inventory the gastropod species in the seagrass meadow of Bahoi village waters and to determine the gastropod community structure through analysis of species density, relative density, species diversity index, and dominance index. The method used was a transect line method along 50 meters and a 1x1m quadrat pulled towards the sea, repeated three times during low tide. A total of 117 individuals were found, belonging to 26 species (11 families and 17 genera) of gastropods in the seagrass meadow of Bahoi village coastal waters. Based on the results, the highest density value was 1.10 ind/m2 with a relative density of 28.20%. Based on the analysis, the dominance index (D) of gastropods in the seagrass meadow of Bahoi village coastal waters was low, with values of D = 0.019 to 0.041, indicating that there was no specific species dominance in the seagrass meadow of Bahoi village coastal waters. This has an effect on the diversity index with a value of H' = 2.51, which is categorized as moderate. These results show that the diversity of gastropod species in the seagrass meadow of Bahoi village waters is quite diverse due to the absence of specific gastropod species dominance. Keywords: Bahoi, Seagrass Meadow, Gastropods, Community Structure. Abstrak   Desa Bahoi memiliki luas hamparan padang lamun ± 16.50 Ha yang berada di antara ekosistem mangrove dan ekosistem terumbu karang. Penelitian ini bertujuan untuk melakukan inventarisasi jenis-jenis gastropoda di hamparan lamun perairan Desa Bahoi, dan mengetahui struktur komunitas gastropoda melalui analisis kepadatan spesies, kepadatan relatif, indeks keanekaragaman spesies, dan indeks dominasi. Metode yang digunakan adalah metode transek garis sepanjang 50 meter dan kuadrat berukuran 1×1m yang ditarik ke arah laut, dan dilakukan ulangan sebanyak 3 kali pada saat air surut.Ditemukan 117 individu yang termasuk ke dalam 26 spesies (11 famili dan 17 genera) gastropoda di hamparan padang lamun perairan pantai desa Bahoi. Berdasarkan hasil penelitian, nilai kepadatan tertinggi sebesar 1,10 ind/m2 dengan kepadatan relatif 28,20%. Berdasarkan hasil analisis, Indeks Dominansi (D) gastropoda di hamparan lamun perairan pantai desa Bahoi tergolong rendah, dengan nilai D=0,019 sampai dengan 0,041 menunjukkan bahwa tidak terdapat dominasi spesies tertentu di hamparan padang lamun perairan pantai desa Bahoi. Hal ini berpengaruh terhadap Indeks Keanekaragaman dengan nilai H’=2,51 sehingga berada pada kategori sedang. Hasil tersebut menunjukkan bahwa keanekaragaman jenis gastropoda di hamparan lamun perairan pantai desa Bahoi cukup beragam dikarenakan tidak adanya dominasi spesies gastropoda tertentu. Kata kunci: Bahoi, Padang Lamun, Gastropoda, Struktur Komunita

Anatomical Characteristics of Macroalgal Species From Bombuyanoi Island, East Bolaang Mongondow Regency, North Sulawesi

This research aims to study the anatomical structure of macroalgae. Sample of macroalga was collected by using Line Intercept Transect (LIT) method with sampling quadrat. Macroalgae samples were dried and separated from the roots, stems, leaves and receptacles (if present). Samples were cut transversely and longitudinally at each section and observed under binoculared microscope of Olympus CX with monitor. Based on the histology, anatomical structure of macroalgae species can be divided into two tissues from outside to inside, namely cortex and medullary cells. The cortex is composed of one layer or more. The cortex is the area between the epidermis and the central column. The medulla cells only have one layer which is the largest layer. Based on the observation result of cells type from observed spesies Eucheuma denticilatum, Gracilaria arcuata, Hydropuntia edulis, G. salicornia, Hypnea valentiae, Turbinaria deccurens, and T. ornata, it shows that cells of medulla become small toward cortex.Indonesian title: Karakteristik anatomi jenis makroalga dari Pulau Bombuyanoi, Kabupaten Bolaang Mongondow Timur, Sulawesi Utar