1 Tracking threatened seabirds in the Namibian Islands’ Marine Protected Area (and beyond)Jessica Kemper1, Katrin Ludynia2, Jean-Paul Roux3, Rian Jones3, Richard B Sherley2 1African Penguin Conservation Project, Namibia 2Dept. of Biological Sciences/Marine Research Institute, UCT, South Africa 3Ministry of Fisheries and Marine Resources, Namibia
2 Eleven coastal seabird species regularly breed on Namibia’s coastEight of these species are listed as locally and/or globally THREATENED, including…
3 African Penguin Globally and locally “ENDANGERED”~25000 pairs, of which ~5800 pairs in Namibia (23% of global population) Breeds at nine islands and two mainland sites in Namibia Main threats: Lack of quality food Lack of quality breeding habitat Disturbance Oil pollution Predation (seals, gulls)
4 Cape Gannet Locally “CRITICALLY ENDANGERED” Globally “VULNERABLE”~13000 pairs in Namibia (11% of global population) Breeds at only six islands; three in SA, three in Namibia Main threats: Lack of (quality) food Disturbance (guano harvest) Oil pollution Accidental bycatch in fisheries Predation (seals) The latest IUCN assessment (two months ago) indicates that the species will probably be reclassified globally endangered in the next assessment (current global decrease is 49% over three generations).
5 Bank Cormorant Globally and locally “ENDANGERED”Global population ~2500 pairs, of which ~2000 pairs on 3 ha Mercury Island Main threats: Disturbance Limited breeding habitat Oil pollution Poor quality food Displacement (Cape Cormorants, seals) An oil spill at Mercury Island could be catastrophic for the survival of the species
6 1. Tracking breeding coastal seabirds:Where and how far away from the colony do they forage? How hard to they have to work to feed their chick(s)? Are there any specific foraging “hotspots” we should protect? TD refers to temperature-depth
7 African Penguins: Using GPS Tdlog data loggers:Devices made by earth&OCEAN technologies (expensive but reliable) Records position at sea every 2-15 minutes, accuracy m Temperature and pressure sensors allow analysis of dive profiles, i.e. how often, how long, how deep birds dive during foraging trips Device design evolving, getting smaller, lighter, more reliable and efficient TD refers to temperature-depth
8 Data loggers need to survive dives to 100 m water depth (sturdy, waterproof housing)Battery life limited (~2-3 days, depending on settings); one or two foraging trips recorded per deployment Bird needs to be re-caught to retrieve data
9 New design (since 2016) Old design (2005 to 2015)
10 Catching a penguin by hand:Unsuspecting candidate
11 Affixing the data logger by weaving a lattice of waterproof Tesa® tape into the feathers (no feather damage):
12 Penguin is returned to its nest (whole procedure takes about 10 minutes) Device is (ideally) collected after two to three days
13 Between 2005 and 2016: Mercury Halifax Possession No. successful deployments 99 109 3 No. foraging tracks recorded 101 165 4 No. field seasons 8 10 1 Diet sampling studies done in conjunction with tracking during some field seasons Only two devices have been lost
14 Cape Gannets: Same devices, attached to tail feathers and lower back of breeding individuals Different settings used to account for longer foraging trips and plunge dives Number of GPS data logger deployments by three separate teams: Mercury Island: 35 (2003, 2005, 2006) Ichaboe Island: 226 (2003 to 2007) Possession Island: 25 (2003)
15 Bank Cormorants: Tracking done at Mercury Island during 2006, 2008 and 2010, using either: MiniGPS loggers, giving positions at 1 sec intervals (5 individuals, 34 tracks), OR Precis TD loggers to record diving data (21 individuals, 112 tracks) Done only in colonies where birds are used to human presence, to minimise disturbance Tracking was done in conjunction with diet sampling and nest observations
16 Some key findings: African Penguins:Some foraging hotspots identified (eg NW of Mercury Island) Foraging effort differs between localities and between years / seasons Foraging distance from the breeding colony is about 20 km Mercury Island tracks ( )
17 Some key findings: Cape Gannets:Birds from Mercury forage mostly inshore and to the north; those from Ichaboe further offshore and to the west Birds travel up to 500 km during a single foraging trip, with an average trip duration of 24 hours Birds travel up to ~120 km from a breeding locality
18 Some key findings: Bank Cormorants:Birds travel up to 8 km during a single foraging trip, and up to 4 km from the island Foraging trips last less than one hour Maximum recorded dive depth was 47.6 m Individuals tend to revisit specific areas to forage Example of an activity profile (Precis TD logger)
19 Designing the Namibian Islands’ Marine Protected Area (NIMPA)Principal aim of the NIMPA is to protect: breeding sites key foraging areas/ranges of Nambia’s threatened coastal seabirds
20 2005-2006 tracking data was crucial in the NIMPA’s designGannet tracks left top, penguin tracks from Mercury right top and Halifax/Possession left bottom, Bank Cormorants right bottom. Instead of having an MPA around each island, this was merged into one MPA. Perhaps mention that the NIMPA is 400 km by 30 km, giving about 1 million ha. It runs from Meob Bay to Chamais Bay and includes all natural seabird breeding islands and islets. Final MPA design (proclaimed 2009) Tracking data Initial MPA design
21 Subsequent GPS logger data of African Penguins, Cape Gannets and Bank Cormorants…forms part of a long-term programme to monitor the efficacy of the NIMPA (see Ludynia et al. 2010, 2012) provides baseline data to assess risks posed by current and/or future activities, e.g. inshore diamond mining in southern Namibia
22 2. Tracking non-breeding coastal seabirds
23 African Penguins The first months after fledging are spent at sea before returning to land to moult First year survival is a crucial factor in population dynamics Monitoring post-fledging movement is vital Satellite technology allows long-term tracking Collaborative project with South African researchers
24 Tracking five newly fledged penguins from Cape Town in 2011:Feeding “hotspots” near Hondeklip Bay and south of Swakopmund From: Sherley et al. 2013
25 Expanding the study in 2013 to include ten fledglings from Halifax and Mercury islandsKiwiSat® (Sirtrack) PTTs Attached to the back with Tesa tape, some glue and cable ties Only top condition (> 3 kg) fledglings chosen
26 A key foraging area south of Swakopmund confirmedJuveniles target areas of high primary productivity Before the near-collapse of sardine stocks, these areas would have held high densities of sardine Suggests that poor juvenile survival/recruitment may be due to them ending up in the wrong spot From: Sherley et al. in review
27 Cape Gannets Post-breeding gannets leave the island in April and return in September/October Relatively little is known about their winter distribution
28 Using geolocator data loggersCheap, small and easy to attach to a gannet’s leg Position data is calculated from light levels (only gives broad-scale indication of position) Bird needs to be caught again to retrieve the device
29 Pilot project (2013) 20 chick-rearing gannets from Mercury Island and 8 birds from Ichaboe Island were equipped 16 devices from Mercury Island and none from Ichaboe Island were retrieved after winter Analysis of collected data is ongoing (watch this space…)
30 Conclusions Extremely valuable insights have been gained so far from tracking some of our threatened coastal seabirds Tracking, particularly of African Penguins, continues The growing time series can (and should) be used for Marine spatial management planning Conservation management Fisheries management (EAF )
31 A big thank you to: For further information or publication reprintsShell Namibia Upstream BV British Ornithologists’ Union Percy Fitzpatrick Institute, UCT Department of Environmental Affairs, SA Seacode Research Group MFMR NACOMA Namdeb University of Kiel CNRS NNF For further information or publication reprints contact me on