A Morphological and Histological Examination of the Pan-tropical Spotted Dolphin (Stenella attenuata) and the Spinner Dolphin (Stenella longirostris) Adrenal Gland

There are at least two races of spotted dolphin, Stenella attenuata, in the eastern Pacific, based on length, color pattern, and skeletal differences. The coastal form is provisionally called S. attenuata graffmani. The offshore form is distinct from a third, Hawaiian race. Likewise, at least three unnamed races of spinner dolphin, S. longirostris, occur in the eastern Pacific. Length, shape of adult male, color pattern, and cranial differences are used to distinguish a Costa Rican, an eastern, and a whitebelly race. An Hawaiian race is distinct from these. A distributional break may indicate two stocks of the striped dolphin, S. coeruleoalba.

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FREKUENSI PEMUNCULAN, TINGKAH LAKU, DAN DISTRIBUSI MAMALIA LAUT DI LAUT SAWU, NUSA TENGGARA TIMUR

BAWAL Widya Riset Perikanan Tangkap ◽

10.15578/bawal.3.3.2010.209-216 ◽

2017 ◽

Vol 3 (3) ◽

pp. 209

Author(s):

Dharmadi Dharmadi ◽

Ria Faizah ◽

Ngurah Nyoman Wiadnyana

Keyword(s):

Marine Mammals ◽

Killer Whale ◽

Sperm Whale ◽

Distribution Patterns ◽

Line Transect ◽

Pilot Whale ◽

Stenella Longirostris ◽

Spinner Dolphin ◽

Stenella Attenuata ◽

Lagenodelphis Hosei

Penelitian mamalia laut dilakukan pada bulan Juli dan Desember tahun 2005 di perairan Laut Sawu, Nusa Tenggara Timur. Tujuan penelitian ini untuk mengetahui tingkah laku, frekuensi pemunculan, dan pola penyebaran mamalia laut. Metode survei menggunakan garis transek dengan pola zig-zag dan dilengkapi dua pengamat (double observer). Delapan spesies mamalia laut yang terdiri atas paus dan lumba-lumba berhasil diidentifikasi, yaitu ikan paus sperma (Physetermacrocephalus), paus pilot (Globicephala macrorhynchus), paus pembunuh kerdil (Feresa attenuata), paus pembunuh (Pseudorca crasidens), lumba-lumba paruh panjang (Stenella longirostris), lumbalumba botol (Stenella attenuata), lumba-lumba fraser (Lagenodelphis hosei), dan lumba-lumba hidung botol (Tursiop truncatus). Tingkah laku mamalia laut yang teridentifikasi selama pengamatan adalah berburu mangsa, melompat ke atas permukaan air, dan berenang menuju arah tertentu. Frekuensi pemunculan tertinggi dilakukan oleh Stenella longirostris yaitu 245 kali atau 84,1% kehadiran pada bulan Juli dan 994 kali atau 60,8% kehadiran pada bulan Desember 2005. Distribusi mamalia laut di Laut Sawu sebagian besar terkonsentrasi di sekitar perairan Lembata, Pantar, danAlor, Nusa Tenggara Timur yang juga didominansi oleh Stenella longirostris. Study on mamals was conducted in the Sawu Sea, East Nusa Tenggara on July and December 2005. The objectives of these research are to study the sighting frequency and the distribution patterns of marine mammals. Survey was conducted using line transect with zig-zag patern that equiped by two observer. Eight species of cetacean, namely sperm whale (Physetermacrocephalus), short fin pilot whale (Globicephala macrorhynchus), false killer whale (Pseudorca crasidens), pigmy killer whale (Feresa attenuata), spinner dolphin (Stenella longirostris), spotted dolphin (Stenella attenuata), fraser’s dolphin (Lagenodelphis hosei), and bottlenose dolphin (Tursiops truncatus). The cetacean behavior during observation are hunting, forfeed jumping in the air, and travelling to certain direction. Stenella longirostris is the frequent observed species compared to the others, where 245 sightings (84,1%) on July and 994 sightings (60,8%) on December 2005. The cetacean distributed in the Lembata, Pantar, and Alor waters, East Nusa Tenggara was dominated by spinner dolphin (Stenella longirostris).

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