Watamu-Malindi and Watamu Banks IMMA

Size in Square Kilometres

951 km2

Qualifying Species and Criteria

Indo-pacific bottlenose dolphin – Tursiops aduncus

Criterion B (1)

Humpback whale – Megaptera novaeangliae

Criterion C (3)

Marine Mammal Diversity 

Tursiops aduncus, Megaptera novaeangliae, Sousa plumbea, Stenella longirostris, Globicephala macrorhynchus, Balaenoptera edeni, Orcinus orca, Physeter macrocephalus, Pseudorca crassidens

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Watamu – Malindi is located in the rich, shallow coastal waters off north-central Kenya and includes the Watamu Banks, a large nearshore banks system known for its world class sport-fishing.  A long-term       photo-identification study shows that Indo Pacific bottlenose dolphins (Tursiops aduncus) are resident in the area,  with mothers and calves frequently observed in the nearshore waters of the Watamu Marine National Park.  Endangered Indian Ocean humpback dolphins (Sousa plumbea) are also present in the area, although they are less well-studied. The Watamu Banks also host humpback whales (Megaptera novaeangliae) belonging to the Southern Hemisphere population labelled ‘Breeding Stock C’ by the International Whaling Commission.   Whales migrate through the IMMA between July and October each year, and observations between 2014 and 2016 included mothers and calves.

Description of Qualifying Criteria

Criterion B: Distribution and Abundance

Sub-criterion B1: Small and Resident Populations 

A resident population of Indo-Pacific bottlenose dolphins has been observed to use the area and this is evident from photo-ID data based on surveys conducted from 2010 to date (Mwang’ombe et al. 2015). Studies were conducted from 2011-2014, including 101 dedicated boat-based surveys between November and April, in 71 km2 of the Watamu area during the northeast monsoon season from 2011-2014. Search effort covered 951 km resulted in 92 sighting records of Indo-Pacific bottlenose dolphins. From 2010 to 2019, 141 individual Indo Pacific bottlenose dolphins have been photo-identified in this area with a high re-sighting rate suggesting residency.  The encounter rate for the 2011 – 14 period for this species was 0.156 sightings/km2. The distribution of Indo-Pacific bottlenose dolphins that occur inside the Watamu-Malindi and Watamu Banks area shows a strong preference for the reefs inside the MPA, where they feed on inshore reef fish. This long-term photo-identification program has been conducted in Watamu since 2010 and this demonstrates that the population of Indo-pacific bottlenose dolphins is resident in Watamu where mother-calf pairs are frequently sighted in the coastal zone. The Watamu Banks are a very well-known sport fishing area and has many record-breaking catches of game fish.

Criterion C: Key Life Cycle Activities

Sub-criterion C3: Migration Routes

The Watamu banks is an important area for breeding and migrating humpback whales, and the Kenya Marine Mammal Network, which logs all citizen science whale sightings, has more records from the Watamu Banks than from any other location.  Although this is biased by effort, it is clear that the Watamu Banks is an important area for migrating and breeding humpback whales. Land-based observations of humpback whales have been made from a fixed land position on a headland near Watamu from an elevation of 29m with a 180-degree view of the sea. Surveys were conducted 4 days a week for a 5-hour period per day (Mwang’ombe et al. 2015).  In 2014 land-based surveys recorded 54 sightings of humpback whale (Megaptera novaeangliae), which was the highest encounter rate (ER =0.51/hour) compared to 2015 and 2016 (ER = 0.17/hour). Calves were sighted in 2014, 2015 and 2016.

Supporting Information

Mwang’ombe, M.G., Pérez-Jorge, S., Charo, K.K., Yaa, J.K., Njuguna, L.N., Trott, S.J. & Spilsbury, J.H. (2015) Cetacean species distribution and encounter rates in the Malindi – Watamu National Marine Reserve 2011 – 2014.  Poster presented at the. In Western Indian Ocean Marine Science Association, Durban, South Africa.

Mwang’ombe, M.G., Pérez-Jorge, S., Charo, K.K., Yaa, J.K., Njuguna, L.N., Trott, S.J. & Spilsbury, J.H. (2017) Improving understanding of whales migration through the Kenyan Inshore waters.  Poster presented at the. In Western Indian Ocean Marine Science Association, Dar-es-salaam, Tanzania.


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