Species composition and diel variation of fish caught by traditional longline fishing

International Journal of Agricultural Technology 2022Vol. 18(5):2135-2146
Available online http://www.ijat-aatsea.com
ISSN 2630-0192 (Online)

Abstract The study of fish species composition and diel variation of fish caught by traditional
longline fishing was conducted during December 2020 to January 2022. Many sizes of circle
hooks ranging from No. 9/0 – No. 18/0 attached with branch lines, main lines and baits
(earthworm and small live fish) were used to collect fish samples from 3 stations along the
middle Chi River, Maha Sarakham, Thailand. In the current study, a total 414 fish belonging to
9 families with 21 species were found. Pangasius larnaudii was the most dominant species in
terms of number (15.2%) whereas Chitala ornate was the most dominant species in terms of
weight (35.6%). The most dominant species in terms of %IRI was Hemibagrus wyckioides
(16.7%). Total cacth per Unit effort of longline fishing ranged from 0.01 – 15.6 kg•day-1 with
an average by 2.8 ±0.31 kg•day-1
. Investigation of diel variation of caught fish during
December 2021 to January 2022 found that Hemibagrus wyckioides, Hemibagrus filamentus,
Pangasius larnaudii and Mastacembelus armatus were caught during both day and night. Four
and 14 fish species were found during the day and night, respectively. Catch per unit effort
during the night with an average of 1,845.5 ±409.1 g. •12 hours-1 was significantly greater than
the catch per unit effort during the day with an average of 264.4 ±132.7 g. •12 hours-1
(p<
0.05). These results suggested that longline fishing should be operated during the night to gain
more catch compared to fishing during the day.
Keywords: Longline fishing, Hook, bait, Species composition, Diel variation, CpUE