Effects of season and mesh size on the selection of narrow-barred Spanish mackerel, Scomberomorus commerson in the Persian Gulf artisanal gillnet fishery

In response to perceived, but unknown variation among the size selection of narrow-barred Spanish mackerel (Scomberomorus commerson) by artisanal gillnetters off Iran, and the need for such data to control exploitation as a precursor to balanced harvesting, the effects of two common mesh sizes (130...

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Bibliographic Details
Published in:Journal of the Marine Biological Association of the United Kingdom 2020-12, Vol.100 (8), p.1321-1325
Main Authors: Pouladi, Mojtaba, Paighambari, Seyed Yousef, Broadhurst, Matt K., Millar, Russell B., Eighani, Morteza
Format: Article
Language:English
Subjects:
Artisanal fisheries
Autumn
Condition factor
Environmental factors
Exploitation
Fish
Fisheries
Fishing
Fishing nets
Gillnets
Gillnetters
Mackerel
Marine fishes
Migratory species
Pelagic fisheries
Scomberomorus commerson
Seasonal variation
Seasonal variations
Seasons
Spawning
Spring
Spring (season)
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Summary:In response to perceived, but unknown variation among the size selection of narrow-barred Spanish mackerel (Scomberomorus commerson) by artisanal gillnetters off Iran, and the need for such data to control exploitation as a precursor to balanced harvesting, the effects of two common mesh sizes (130 and 140 mm stretched mesh opening made from multifilament twine) on catches were investigated over one fishing year (nine months encompassing autumn to spring). Both mesh sizes mostly caught S. commerson at fork lengths (FL) larger than mean sizes at maturity (>67 cm), with the mean size selection incrementally increasing in the 130-mm mesh gillnet from autumn, and especially during spring. The greater selection occurred concurrent with an increasing condition factor (CF) among S. commerson, which typically spawn in late spring/early summer. Conversely, the relative size-selection of the 140-mm mesh gillnet decreased in spring, attributed to increasing CF precluding the capture of larger fish. Such seasonal variation in size selection might be countered by increasing mesh size to ~145 or 150 mm in spring. However, the existing 140-mm mesh might positively affect stock biomass by allowing larger, more fecund fish to avoid capture during spawning. The data support the strong influence of biological and environmental factors on gillnet size selection, which might also extend to other migratory, pelagic species.
ISSN:0025-3154
1469-7769
DOI:10.1017/S002531542000123X