Zanzibar Humpback Research: Fishing Nets and Bycatch Threats

Seeing the amount of nets actually out on the water every day brings home just how much of a threat these pose to both target and non-target coastal marine species.

Seeing the amount of nets actually out on the water every day brings home just how much of a threat these pose to both target and non-target coastal marine species. Khamis with net broken from whale entanglement. This week, news of two broken net close to shore here at Kizimkazi Dimbani filters through from our fisherman network turning our focus back to the imminent bycatch issue in net fisheries whereby accidental drowning in fishing gear is an all too common problem, especially for coastal species throughout the whole East African region and elsewhere in the world. The drift and bottom set gillnet fisheries around Zanzibar (Unguja Island) pose a daily threat to the local population of Indo-Pacific bottlenose and humpback dolphins (pomboro) in addition to causing seasonal bycatch of humpback whales (nyangumi). To date dolphin meat from dead by-caught dolphins is still used as bait in longline fisheries for shark and blubber from dead whales is turned to oil and used e.g. to waterproof boats. Seeing the amount of nets actually out on the water every day brings home just how much of a threat these pose to both target and non-target coastal marine species. During many a survey out in the field our efforts of collecting vital behavioural data and photo ID’s for future conservational efforts often becomes fraught with worry and concern when our focus animal, more often than we would like to see, swims too close for comfort to nets. At times it’s even difficult to navigate our boat safely through the maze of nets that fill the shallow waters. Whale with net marks from previous entanglement. On several occasions we have observed mother and calf navigating dangerously close to and through areas thwart with nets. We sigh with relief with each safe passing of mother and calf, who just about avoid becoming caught up in and entangled in the gear. This again re-enforces the need for action and mitigations efforts as soon as possible. We are making progress towards redistributing ‘pingers’ (acoustic alarms) which act as deterrents to the dolphin population by alerting them to the presence of these nets. However, further research into this area is required and funding needs to be secured in order to achieve substantial mitigation efforts. New batteries purchased as each the life expectancy of about 2 years. Additional pingers are also necessary to purchase as each fisherman requiring six pingers per (500m) net. However, this solution can’t be applied to the whale because they do not respond to the pinger sound and an alternative solution to reduce incidental bycatch is required. We are currently continuing in our efforts to develop ‘weak links’ that can be incorporated into the nets, in theory allowing the net to break if a whale swims into it preventing a whale from becoming entangled completely, however this potential solution still requires further developments, time and money! One economic and conservational solution could also be to incorporate sustainable whale-watching activities into the area, replace fishing efforts when the whales are present. Fisherman could out take paying tourist to watch them as oppose to setting their nets. Such solutions again fall dependent upon requiring money to initialise and maintain and thus require continued support and funding. Our project friend Mwalimo is also one of the local long-line fisherman and one evening decided he’d like to tell us a little bit about himself, keen to talk to the outside world he writes;

Mwalimo and Kristin writing blogs ‘’My name is Mwalim I was born in 1960 at Kizimkazi Dimbani. I studied in a school at Kizimkazi Mkunguni also I finished at school in 1985 and married in 1990. Me, I was a fisherman for a line net basket traps and I have more than 200 chickens in my special house near the junction road at Mkunguni. Also I was a captain of the tourist boat in our harbour at Dimbani and  I’m farming many crops like cassava, yams,  papayas, aubergine, chillies and bananas as well as many others things which grow  in our villages.  I get a many friends from European countries including England, America, Sweden, Belgium and South Africa. Those they come to Zanzibar to make the project of dolphin, whales, turtles, sharks and many sea creatures. The first best friend is Mr Per and the second friend is Fredrik and the third is Kristin. From 2010 up to 2011, including this year’s group, all students were very bright and they were no problems to me myself and were lovely and very kind to all children in our village. God bless Rachael, Lucy, Kyla and Kristin too.  I can say that thanks for your help and we shall see you again another time in 2012!  Bye bye, yours sincerely, Mwalim’’

Meal of the week: after agreeing to do Ramadhan (fasting for the day) we got to enjoy a tasty Futari (evening meal during Ramadhan), sharing the hospitality with the staff at Karamba resort. Porridge (uji) for starters, coconut tambi (local noodles), fish (samaki) with cassava (muhogo) and dates (tende). Tutaonana badaye (see you later), -- The Zanzibar Humpback Whale Team To read the previous post in the team in Zanzibar, click here. For more information on the International Fund for Animal Welfare effort to save animals in crisis around the world visit              

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Brian Sharp, Emergency Relief Officer, Stranding Coordinator
Manager, Marine Mammal Rescue and Research
Dr. Maria (Masha) N. Vorontsova, Senior Advisor to the IFAW Marine Conservation
Senior Advisor to the IFAW Marine Conservation Program
Matt Collis, Director, International Policy
Director, International Policy
Patrick Ramage, Program Director, Whales
Program Director, Marine Conservation