Gillnet selectivity of the Indian oil sardine Sardinella longiceps fished in the Sea of Oman

Anesh Govender, Hamed Al-Oufi

Abstract


The size selectivity of drift gill-nets for Sardinella longiceps was investigated in the Sea of Oman using a range of nets between 3.3 and 5.7 cm stretched mesh size. All nets had a hanging ratio of 0.5. A total of 1 211 Indian oil sardines were caught in 5 experimental nets, the majority of which were retained by the 3.3, 3.8 and 4.5 cm mesh nets. Peak selectivity was reached at 14.9 cm FL for the 3.3 cm mesh size increasing to 16.9 cm for the 3.8 cm mesh size. The estimated and observed length frequency distributions were unimodal. A log-normal selection function indicated that the highest selectivity was obtained when the length class to mesh size (l:m ) ratio was 4.4. Sardinella longiceps's relative abundance was estimated to be the highest at 16.4 cm FL, with numbers decreasing beyond this peak. This would indicate that selectivity by gilling is optimal with a mesh size of 3.8 cm with nets having a hanging ratio of 0.5. This mesh size appears to satisfy two criteria:  high catch efficiency and protection of juveniles.

Keywords


Sardine; gill net; selectivity; mesh-size; Arabian Sea

Full Text:

PDF

References


Al-Al-Abdessalaam, T.Z.S., 1995. Marine Species of the Sultanate of Oman. Muscat: Marine Science and Fisheries Centre, Ministry of Agriculture and Fisheries. 412 p.

Al-Barwani M, Prabhakar A, Dorr J, Al-Manthery M., 1989. Studies on the biology of Sardinella longiceps (Valenciennes) in the Sultanate of Oman, 1985-1986. Kuwait Bulletin of Marine Science 10,201-209.

Anonymous, 2013. Annual Fisheries Statistical Year Book for 2013. Muscat: Ministry of Agriculture and Fisheries Resources.

Carlson, J.K., Cortés E. 2003. Gillnet selectivity of small coastal sharks off the southeastern United States. Fish Res 6,:405-414.

Dorr, J.A., 1991. Small pelagics final report for the contract for technical services for staffing the Marine Science and Fisheries Center. Project No 272-01011-1.

Gray, C.A., Broadhurst, M.K., Johnson, D.D., Young, D.J., 2005. Influences of hanging ratio, fishing height, twine diameter and material of bottom-set gillnets on catches of dusky flathead Platycephalus fuscus and non-target species in New South Wales, Australia. Fish Sci 71,1217-1228.

Hamley, J., 1975. Review of gillnet selectivity. J Fish Res Board Can 32,1943-1969.

Hovgård. H., 1996. A two-step approach to estimating selectivity and fishing power of research gill nets used in Greenland waters. Can J Fish Aquat Sci 53,1007-1013.

Hovgård, H, Lassen, H. 2000. Manual on estimation of selectivity for gillnet and longline gears in abundance surveys. Rome: FAO.

Kawasaki, T. 1991. Long-term variability in the pelagic fish population. In: Kawasaki, T., Tanaka, S., Tola, Y., Taniquiche, A., editors. The long-term varaiability of pelagic fish populations and their environment. New York: Pergamon Press.

Kirkwood, G.P., Walker, T.I. 1987. Gill net mesh selectivities for gummy shark, Mustelus antarcticus Günther, taken in south-eastern Australian waters. Aust J Mar Freshw Res 37,689-697.

Klust, G. 1982. Netting materials for fishing gear. Rome: FAO. 175 p.

Lebreton, J.D., Burnham, K.P., Clobert, J, Anderson, D.R., 1992. Modeling survival and testing biological hypotheses using marked animals: A unified approach with case studies Ecol Monogr 62,67-118.

Madsen, N., Holst, R., Wileman, D., Moth-Poulsen, T., 1999. Size selectivity of sole gill nets fished in the North Sea. Fish Res 44,59-73.

Márquez-Farias, J.F., Corro–Espinosa, D., Castillo–Géniz, J.L., 2005. Observations on the biology of the Pacific sharpnose shark (Rhizoprionodon longurio, Jordan and Gilbert, 1882), captured in southern Sinaloa, México. Journal of Northwest Fishery Science 35,107-114.

Millar, R.B., 2000. Untangling the confusion surrounding the estimation of gillnet selectivity. Can J Fish Aquat Sci 55,1328-1337.

Millar, R.B., Fryer, R.J., 1999. Estimating the size-selection curves of towed gears, traps, nets and hooks. Rev Fish Biol Fish 9, 89-116.

Reis, E.G, Pawson, M.G., 1999. Fish morphology and estimating selectivity by gillnets. Fish Res 39,263-273.

Salvanes, A.G.V., 1991. The selectivity for cod (Gadus morhua) in two experimental trammel-nets and one gillnet. Fish Res 10,265-285.

Santos, M.N., Monteiro, C.C., Erzini, K., Gerard, L., 1998. Maturation and gill-net selectivity of two small sea breams (genus diplodus) from the Algarve coast (South Portugal). Fish Res 36,185-194.

Siddeek, M.M., Al-Habsi, H.N., Al-Jufaily, S.M., Al-Ghafry, I.N., 1994. Spawning cycle, recruitment patterns and maturity length of Indian Oil sardine at Al-Aziba, the Sea of Oman. In: Chou, L.M., Munro, A.D., Lam, T.J., Chen, T.W., Cheong, L.K.K., Ding, J.K., Hooi, K.K., Khoo, H.W., Phang, V.P.E., Shim, K.F., Tan, C.H., editors. The Third Asian Forum. Manila, Philippines: Asian Fisheries Society.

Stengel, H., Al Harthy, A., 2002. The traditional fishery of the Sultanate of Oman (fishing gear and methods). Muscat: Ministry of Agriculture and Fisheries, Directorate General of Fisheries Resources, Marine Science and Fisheries Center. 147 p.




DOI: http://dx.doi.org/10.24200/jams.vol24iss0pp19-23

Refbacks

  • There are currently no refbacks.




Copyright (c) 2018 Anesh Govender, Hamed Al-Oufi

Creative Commons License
This work is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International License.

JAMS 2017-CC BY-ND

This journal and its content is licensed under a Attribution-NoDerivatives 4.0 International.

Flag Counter