INTRODUCTION
Octopuses are marine mollusks belonging to Phylum Mollusca, Family Octopodidae. They inhabit shallow tropical, subtropical, and temperate waters worldwide.
In the Western Indian Ocean region, two common species (Octopus cyanea and Octopus vulgaris) are recorded in Kenyan fisheries. This study aims to provide updated information on fishery dynamics, stock status, and biological aspects of octopus.
POPULATION STRUCTURE OF Octopus cyanea
Preliminary results indicate that 99% of octopus caught were Octopus cyanea, with a total landed catch of 1,724 kg.
STUDY AREA
Shimoni, located on Kenya’s south coast. Representative samples were taken for length and weight measurements, with dorsal mantle length (DML, cm) measured from the midpoint between the eyes to the posterior tip of the body. Sex was recorded for each specimen.
SEX RATIO & MANTLE DISTRIBUTION
Mantle length distribution (N = 1,319) was analyzed using 5 cm length intervals.
A t-test showed significant variation (p<0.05, t = 1.9832, tc = 1.9618). The sex ratio among 1,319 specimens was 1 female: 0.8 males.
DISCUSSION
Findings suggest Octopus cyanea is abundant in this region. Catches vary across fishing grounds in terms of size and quantity. Seasonal variations indicate octopus is caught throughout the year. Effort and catch rates are higher during the Northern Monsoon season.
CONCLUSION
Regular assessments are necessary to ensure responsible fisheries management. Findings suggest Octopus cyanea is the most abundant species in Kenya’s south coast.
ACKNOWLEDGMENTS
Special thanks to Kenya Marine & Fisheries Research Institute and The Technical University of Mombasa for their support and mentorship.