Title: Length - Weight Relationship of Octopus cyanea (Gray, 1849) in Zanzibar: Informing Sustainable Management Practices in Zanzibar Fisheries
Authors: Ali M. Ussi, Narriman S. Jiddawi and Salum S. Hamed
Volume: 9
Issue: 2
Pages: 305-315
Publication Date: 2025/02/28
Abstract:
This study explored the length-weight relationship in octopus populations at Unguja Ukuu and Uroa, Zanzibar, by analysing data from 8,127 octopuses collected throughout 2020. We aimed to understand growth patterns and their implications for sustainable fisheries management. The analysis involved quantifying weight frequency distributions, assessing the correlation between length and weight, identifying key weight classes, and observing seasonal growth fluctuations. Our findings reveal a robust positive correlation between length and weight, with Coefficient of determination values between 0.5831 and 0.8037, suggesting reliable growth models for these populations. Notably, male octopuses consistently recorded higher mean weights than females, with the highest weight peaks in June and October, highlighting significant seasonal and sex-specific growth variations that may be linked to reproductive and metabolic differences. The study also detected negative allometric growth at both sites, implying that environmental factors like food availability and habitat conditions may drive these octopuses to increase in length more than weight. These results emphasise the need for integrating biological and ecological data into management strategies, advocating for adaptive measures such as size-specific harvesting regulations and seasonal habitat protections. This approach is crucial for maintaining the sustainability of octopus populations in Zanzibar, thereby supporting the region's marine biodiversity and the economic stability of its fisheries.